71 results on '"Andrew M. McKenzie"'
Search Results
2. Gender differences in job satisfaction among gig workers in Bangladesh
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Mou Rani Sarker, Tanjum Afrin Taj, Md Abdur Rouf Sarkar, Md. Fuad Hassan, Andrew M. McKenzie, Md. Abdullah Al Mamun, Dweep Sarker, and Humnath Bhandari
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Digitalization ,Employment ,Gender ,Gig economy ,Job satisfaction ,Online job ,Medicine ,Science - Abstract
Abstract The gig economy (temporary, contract, and freelance online jobs rather than permanent positions) is a component of the fourth industrial revolution and preview of future work. The rise of digital platforms has increased career opportunities and income potential, particularly for women. Yet, the sex-disaggregated evidence regarding platform usage, employment characteristics, and working motivations and satisfaction remains untapped. Using data from a quantitative survey of Bangladeshi gig workers (242 men and 201 women) conducted in 2022, this paper addresses these gaps between male and female workers. The gig economy appears to be gender-segregated across digital platform usages and working categories. Women tend to prioritize digital work options for managing multiple responsibilities, while men are often driven by the potential for higher income. This study conceptually utilized the two-factor theory and empirically ordered a probit model to identify gender differences in job satisfaction. Job satisfaction was significantly increased by work-life balance, monthly income, and social-media connection, while an increase in working hours, complexity in payment systems, and unstable networks all led to a decrease in job satisfaction. The findings have implications for the future growth of the gig economy, provide new insights into gender differences in job satisfaction, and underscore the need for gender-sensitive policies in the online labor market.
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- 2024
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3. Demand for milk and milk products in the rural household of Bangladesh: A panel data analysis
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Eshrat Jahan Mahfuza, Mohammad Jahangir Alam, and Andrew M. McKenzie
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Balance panel data ,AIDS model ,Fixed effects model ,Milk and milk products ,Rural Bangladesh ,Agriculture (General) ,S1-972 ,Nutrition. Foods and food supply ,TX341-641 - Abstract
Milk is considered an essential source of protein for people of all ages. However, Bangladeshi people, particularly those living in rural areas, tend to consume less milk and milk products than necessary. Therefore, this study aims to investigate the demand for milk and milk products among rural consumers and the factors affecting their consumption habits. The study utilizes balanced panel data from three waves of the Bangladesh Integrated Household Survey: 2011–12, 2015, and 2018–19, collected by the International Food Policy Research Institute. Both the Almost Ideal Demand System (AIDS) and Fixed Effects Model were employed. The expenditure elasticity for liquid milk, powdered milk, and condensed milk was found to be 1.013, 1.856, and 1.060, respectively, indicating that these products are considered luxury goods in rural Bangladesh. Additionally, powdered milk is more price-sensitive than liquid or condensed milk in these areas. Milk and milk products exhibit a substitutable relationship based on the Slutsky and Cournot cross-price elasticities matrix. Consumption of liquid milk is significantly influenced, either positively or negatively, by several factors, including age, education, family size, ownership of dairy animals, income, expense of food, and year. Furthermore, while the consumption of powdered milk is increasing over time, factors such as family size and livestock ownership negatively impact its consumption. Similarly, the consumption of condensed milk is negatively affected by education and ownership of dairy animals. Based on our study results, we recommend increasing household income through on and off-farm job creation, promoting educational campaigns on the benefits of milk, and supporting livestock ownership to reduce reliance on processed milk products.
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- 2024
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4. Agricultural extension service, technology adoption, and production risk nexus: Evidence from Bangladesh
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Mohammad Jahangir Alam, Paresh Kumar Sarma, Ismat Ara Begum, Jeff Connor, Lin Crase, Sheikh Mohammad Sayem, and Andrew M. McKenzie
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Agricultural risk ,Risk management strategies ,Technology adoption ,Extension services ,Stochastic modelling ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
Rice production is inherently risky and volatile, and farmers in Bangladesh face a wide range of risks, including weather, pest and disease attacks, interruptions to input supply, and market-associated risks. Moreover, poor farm households often perceive risks in adopting new technology, even though it could improve productivity and food security. Such households are thus caught in a “risk-induced trap” that precludes them from realizing the benefits of technological innovation. Extension service is one way to help farmers improve risk management skills and escape risk-induced traps, but there is limited empirical analysis of its impact in Bangladesh. The objective of the study is to measure the nexus between agricultural extension services, technology adoption, and production risks as well as women empowerment in agriculture index. IFPRI utilized stratified random sampling to determine the 5603 households in 2018 (which is nationally called the BIHS-2018 dataset) from rural and pre-urban areas of Bangladesh. Out of these 5603 households, 2663 households were specifically selected for the study related to rice farming to achieve the main objective of the study. Focusing on rice farming, a moment-based Poisson regression model is estimated with 2SLS and identifies risks associated with key technologies and potential productivity and risk-reducing effects. The results revealed that wealthier households are more likely to adopt technology for minimizing production risk and women's empowerment which can positively affect productivity by mitigating risk. The result revealed a positive and significant difference in WEAI between the AES participant and non-participant group. We find that engagement in agricultural extension services was associated with technology adoption and production risk reduction. The agricultural extension services increased, technology adoption by 4.2 % and decreased production risk by 2.4 %. Based on the findings, it is concluded that more comprehensive extension services can enhance rice production and ameliorate farmers' risk in rice production to some extent.
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- 2024
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5. Identification of influential weather parameters and seasonal drought prediction in Bangladesh using machine learning algorithm
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Md. Abdullah Al Mamun, Mou Rani Sarker, Md Abdur Rouf Sarkar, Sujit Kumar Roy, Sheikh Arafat Islam Nihad, Andrew M. McKenzie, Md. Ismail Hossain, and Md. Shahjahan Kabir
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Medicine ,Science - Abstract
Abstract Droughts pose a severe environmental risk in countries that rely heavily on agriculture, resulting in heightened levels of concern regarding food security and livelihood enhancement. Bangladesh is highly susceptible to environmental hazards, with droughts further exacerbating the precarious situation for its 170 million inhabitants. Therefore, we are endeavouring to highlight the identification of the relative importance of climatic attributes and the estimation of the seasonal intensity and frequency of droughts in Bangladesh. With a period of forty years (1981–2020) of weather data, sophisticated machine learning (ML) methods were employed to classify 35 agroclimatic regions into dry or wet conditions using nine weather parameters, as determined by the Standardized Precipitation Evapotranspiration Index (SPEI). Out of 24 ML algorithms, the four best ML methods, ranger, bagEarth, support vector machine, and random forest (RF) have been identified for the prediction of multi-scale drought indices. The RF classifier and the Boruta algorithms shows that water balance, precipitation, maximum and minimum temperature have a higher influence on drought intensity and occurrence across Bangladesh. The trend of spatio-temporal analysis indicates, drought intensity has decreased over time, but return time has increased. There was significant variation in changing the spatial nature of drought intensity. Spatially, the drought intensity shifted from the northern to central and southern zones of Bangladesh, which had an adverse impact on crop production and the livelihood of rural and urban households. So, this precise study has important implications for the understanding of drought prediction and how to best mitigate its impacts. Additionally, the study emphasizes the need for better collaboration between relevant stakeholders, such as policymakers, researchers, communities, and local actors, to develop effective adaptation strategies and increase monitoring of weather conditions for the meticulous management of droughts in Bangladesh.
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- 2024
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6. The effect of total factor productivity on the food security and livelihood vulnerability of farm households in Bangladesh
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Paresh Kumar Sarma, Mohammad Jahangir Alam, Ismat Ara Begum, and Andrew M. McKenzie
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climate vulnerability ,dietary diversity ,farm efficiency ,total factor productivity ,Bangladesh ,Nutrition. Foods and food supply ,TX341-641 ,Food processing and manufacture ,TP368-456 - Abstract
Food security and livelihood vulnerability are important issues for the economic sustainability of developing countries like Bangladesh. This study examines the influence of total factor productivity (TFP) on the livelihood vulnerability and food security of rice farming households in Bangladesh. Data from 1,841 rice farming households were extracted from the Bangladesh Integrated Household Survey (2015 and 2018) conducted by the International Food Policy Research Institute. Various statistical methods, such as the stochastic frontier model, principal component analysis, path analysis using structural equation modeling, and multivariate regression, were employed to analyze the data. The study utilizes a multivariate modeling approach that combines the stochastic frontier model to determine TFP and sophisticated methodologies to estimate the livelihood vulnerability index (LVI) and women’s empowerment in agriculture index (WEAI). The LVI, household dietary diversity Score (HDDS), TFP, and WEAI scores were 0.454, 10.72, 0.703, and 0.717, respectively. The results indicate a significant relationship between TFP and both LVI and HDDS. Higher TFP is associated with lower LVI and higher HDDS among rice farming households, suggesting that improving TFP can enhance food security and reduce vulnerability. The multivariate regression analysis reveals that TFP, household wealth index, women’s empowerment in agriculture index, per capita food expenditure, household level welfare, and household size have a positive significant impact on HDDS, while TFP is negatively associated with LVI, per capita food expenditure and household size. The findings underscore the importance of increasing TFP to improve food security, reduce livelihood vulnerability, and achieve sustainable development goals in countries like Bangladesh. Higher TFP yields positive outcomes regarding household dietary diversity and livelihood vulnerability, highlighting the need for agricultural policies that prioritize TFP enhancement. Policymakers and professionals can use these findings as a roadmap to implement advanced agricultural policies to achieve food security and reduce livelihood vulnerability. Improving household dietary diversity and reducing livelihood vulnerability can be achieved by focusing on increasing TFP, enhancing household wealth, women’s empowerment, per capita food expenditure, household welfare, and household size. Therefore, increasing TFP should be considered in the design of policies aiming to achieve SDGs Goal 2.
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- 2024
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7. Does rural transformation affect rural income inequality? Insights from cross-district panel data analysis in Bangladesh
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Al Amin Al Abbasi, Subrata Saha, Ismat Ara Begum, Maria Fay Rola-Rubzen, Andrew M. McKenzie, and Mohammad Jahangir Alam
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Rural transformation ,Income inequality ,Gini coefficient ,Bangladesh ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
Rural transformation plays a crucial role in enhancing the income and employment prospects of the rural labor force. We investigate the effects of rural transformation on rural income inequality at the district level in Bangladesh using data from five years of nationally representative Household Income and Expenditure Surveys. The Gini coefficient is used to measure rural income inequality. In contrast, the share of high-value agricultural outputs and the share of rural non-farm employment are used as indicators of rural transformation. We find that rural income inequality is positively associated with the share of high-value agricultural outputs and the share of rural non-farm employment. The non-linear regression result shows an inverted U-shaped relationship between rural transformation and income inequality, which indicates that income inequality initially increases with rural transformation but decreases in the long run. Additionally, we find that rural income inequality is positively correlated with the proportion of household education expenditures, agricultural rental activity, and the share of remittances. This study also reveals that income inequality in rural areas of Bangladesh has a significant negative correlation with the government's social safety net program.
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- 2024
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8. Supply chain challenges and recommendations for international development agriculture projects: an application of the FGD-fuzzy Delphi approach
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Md. Raquibuzzaman Khan, Mohammad Jahangir Alam, Nazia Tabassum, Niaz Ahmed Khan, and Andrew M. McKenzie
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History of scholarship and learning. The humanities ,AZ20-999 ,Social Sciences - Abstract
Abstract International development (ID) agriculture projects play a crucial role in ensuring the long-term viability of agriculture-based economies in developing countries. While, unlike other development projects, these projects face unique supply chain challenges that agriculture development projects focus primarily on increasing crop production to ensure food security in a country, which is affected not only by social or national context issues but also by natural environments. Since no previous research has investigated the supply chain issues of ID agriculture projects, this study makes a significant contribution to the literature by identifying the key supply chain challenges of ID agriculture projects in a developing country context and proposing specific solutions to these challenges. Initially, the study conducted a literature review to generate a primary list of project supply chain challenges. To identify more significant and relevant challenges, the study conducted focus group discussions and consulted with an expert panel; it identified seventeen critical challenges and provided specific recommendations to address each challenge. The recommendations were then ranked using the fuzzy Delphi method based on their importance. Certain critical challenges, such as political influence, are exacerbated by the unique project and context environments. While others are the result of donors’ incompatible strategies and influences (e.g., donor-incompatible regulations). Some of them are created by both the host nation and the donors (delayed project launch, for example). Moreover, the projects face specific challenges posed by natural environments (such as natural disasters). To ensure value for money within the project’s scope, it is recommended that the professionals adopt the most important strategies to address the challenges. Not only are the findings impressive for industry professionals, but also policymakers, development partners, academics, and future researchers.
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- 2023
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9. Value chain analysis of jute fiber in Bangladesh
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S.M. Moniruzzaman, Mohammad Jahangir Alam, Dabasis Sharma, Ismat Ara Begum, Marco Tulio Ospina Patino, and Andrew M. McKenzie
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Value chain ,Jute ,Marketing margin ,Marketing channel ,Value addition ,SWOT analysis ,History of scholarship and learning. The humanities ,AZ20-999 ,Social sciences (General) ,H1-99 - Abstract
Jute often referred to as Bangladesh's “golden fiber” offers numerous environmental advantages along with significant industrial and economic importance. It is a crucial source of export earnings for Bangladesh. Beyond its use in house decoration materials, jute is employed in the production of twine, mats, carpets, sacks, and hessian clothing, among other products. This study aimed to assess the value chain of jute fiber in Bangladesh. Primary data were collected from 90 jute farmers and 233 chain participants across different stages of the value chain selected through simple random and purposive sampling, respectively, in 2019. Mapping strategies and marketing margins were employed to analyse the value addition of each actor. The benefit-cost ratio of 1.44 demonstrates the profitability of jute cultivation. The study identified that the highest share of the total value addition by farmers was 52.80% through the ‘Farmer-Faria-Kutcha Baler-Mill’ channel in Faridpur district, 59.66% through the ‘Farmer-Faria-Aratdar-Mill’ channel in Rangpur district, 60.52% through the ‘Farmer-Faria-Aratdar-Mill’ channel in Dinajpur district, and 58.87% through the ‘Farmer-Faria-Aratdar-Mill’ channel in Kishoreganj district. Per quintal, gross and net marketing margins for farmers were Taka 569 and Taka 537, respectively. Pucca balers cum exporters accounted for the highest proportion of gross marketing margin (41.30%) and net marketing margin (44.34%), while Farias contributed the lowest share (6.77% and 3.63%). Finally, based on the research findings, several policy measures are recommended to revitalize this potential sector in Bangladesh.
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- 2024
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10. Consumers’ interest and willingness to pay for traceable vegetables- An empirical evidence from Bangladesh
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A.N.M. Faijul Kabir, Mohammad Jahangir Alam, Ismat Ara Begum, and Andrew M. McKenzie
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Traceability system ,Traceable vegetables ,Vegetable supply chain ,Contingent valuation method ,Willingness to pay ,Determinants ,Nutrition. Foods and food supply ,TX341-641 ,Food processing and manufacture ,TP368-456 - Abstract
Urban consumers’ concerns have focused attention on whether a food traceability system should be implemented in Bangladesh to minimize the production and distribution of unsafe and poor-quality food products. A cross-sectional survey was conducted among 220 consumers in two main cities Dhaka and Mymensingh of Bangladesh to examine the traceability system in the vegetable supply chain from an ex-ante perspective. The objective is to identify the preferences and willingness to pay (WTP) for the traceability attributes and examine the factors influencing their WTP for traceable vegetables. The results show that over 90% of the consumers put their emphasis on traceability attributes associated with: pesticides and last date of spraying information, fertilizer information, and harvest date. On the other hand, over 85% of consumers showed interest in GM information of vegetables. The mean WTP is found to be 5.84 Tk. (US$0.068) and 5.90 Tk. (US$0.069) per kg respectively for brinjal and tomatoes. This reflects a 19.5% and 19.7% additional monetary payment over and above the purchase price for conventional brinjal and tomatoes respectively. The empirical findings indicate that income and quality perception scores have positive and significant effects on consumer WTP for traceable brinjal and tomatoes.
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- 2023
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11. Spatial market integration of rice in Bangladesh in the presence of transaction cost
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Mohammad Jahangir Alam, Andrew M. McKenzie, Ismat Ara Begum, Jeroen Buysse, Eric J. Wailes, Md. Abdur Rouf Sarkar, Abdullah Al Mamun, and Guido Van Huylenbroeck
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Market integration ,Rice markets ,Transaction cost ,Bangladesh ,Nutrition. Foods and food supply ,TX341-641 ,Agricultural industries ,HD9000-9495 - Abstract
Abstract Modeling transaction costs is of particular importance when analyzing price integration in developing countries. Spatial price integration among five major Bangladesh rice markets are examined over the post-liberalization period that covered a long time span from January 1999 to December 2021, the longest period covered ever. We account for nonlinear price adjustments induced by transaction costs using a threshold cointegration approach to account for the impact of transaction costs in the price adjustment process. Our results show that large price deviations from long-run equilibrium are corrected within 2–3 months. Our results provide strong supporting evidence of the presence of threshold effects, which means that large transaction costs contribute to slow equilibrium price adjustments. Thus, our results provide important policy implications for Bangladesh rice markets, namely that polices aimed at reducing transaction costs are needed to engender greater pricing efficiency in Bangladesh rice markets.
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- 2022
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12. Consumers’ preference for purchasing vegetables in Bangladesh: What matters?
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A.N.M. Faijul Kabir, Mohammad Jahangir Alam, Ismat Ara Begum, and Andrew M. McKenzie
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Vegetable consumer preferences ,Price consciousness ,Bangladesh ,History of scholarship and learning. The humanities ,AZ20-999 ,Social sciences (General) ,H1-99 - Abstract
This study assesses Bangladeshi consumer-preferred traits while purchasing vegetables, considering four attributes -freshness, price, quality, and safety together with the socio-demographic variables of consumers. In addition, this study also aims to find the factors influencing consumers' price consciousness while purchasing vegetables. A total of 220 consumers were surveyed in person across Bangladesh's two main cities- Dhaka and Mymensingh. We find that age, education, income, and food expenditure are the discriminating factors influencing consumer preferences for vegetable attributes. Additionally, we show that income, food spending, shopping patterns, and the purchase site impact consumers' price consciousness while buying vegetables. Our results indicate that higher-income and well-educated Bangladeshi buyers are ready to shell out extra for fresh vegetables compared to their lower-income and less-educated counterparts who are more price-conscious. Importantly, our results show that consumers in a developing country, accounting for socio-demographic characteristics, share many of the same preference traits and price consciousness as those in developed countries when purchasing vegetables.
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- 2023
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13. Consumer concern about food safety hazards along the vegetables value chain in Bangladesh
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Moumita Deb, Mohammad Jahangir Alam, Md Salauddin Palash, Ismat Ara Begum, and Andrew M. McKenzie
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Food safety ,Consumer concern ,Vegetables ,Consumers’ trust ,History of scholarship and learning. The humanities ,AZ20-999 ,Social sciences (General) ,H1-99 - Abstract
The study analyzes consumer concerns regarding food safety hazards along Bangladesh's major vegetable value chain. By collecting data from a consumer survey of 140 samples, the study investigated the worries about chemical, biological, and lifestyle hazards of major vegetables. The findings reveal that consumers' concerns about chemical, biological, and lifestyle hazards varied significantly depending on their education level, marital status, occupation, and income. Consumers are most concerned about chemical hazards, while they are least concerned about lifestyle hazards. More precisely, consumer concerns about chemical hazards are significantly and positively associated with education, income, marital status, and sources of information; biological hazards are significantly and positively affected by education, marital status, family size, sources of information, and presence of a child in the family; and lifestyle hazards are significantly and positively affected by education, income, marital status, and sources of information. We found that consumer trust in vegetable value chain actors about safe food practices is significantly and negatively related to food safety concerns. The government should provide customers with additional data to assist them in identifying the inherent food safety and quality attributes.
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- 2023
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14. The Effect of E. coli O157:H7 on Beef Prices
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Andrew M. McKenzie and Michael R. Thomsen
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beef prices ,escherichia coli o157 : h7 ,event studies ,food safety ,product recalls ,Agriculture - Abstract
Using an event study, we examine the impact of recalls for E. Coli O157:H7 on wholesale and farm-level beef prices. Prices for boneless beef, a high-volume product primarily used for processing into ground beef, react negatively to recalls, suggesting incentives exist for packing firms to adopt measures that reduce the risk of contamination. However, there is no reaction in live cattle prices and very little reaction in boxed beef prices to recall events. This suggests short-run price responses found at the wholesale level for boneless beef do not transmit back to the farm level.
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- 2001
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15. The impact of financial institutions on exchanges in the agricultural commodity supply chain: An information economics perspective
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Jessica L. Darby, Jason W. Miller, Brent D. Williams, and Andrew M. McKenzie
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Business, Management and Accounting (miscellaneous) ,Management Science and Operations Research - Published
- 2022
16. Characterizing implied volatility functions from agricultural options markets
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Andrew M. McKenzie, Michael R. Thomsen, and Michael K. Adjemian
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Economics and Econometrics ,Agricultural and Biological Sciences (miscellaneous) - Published
- 2022
17. Factor Model Index for Commodity Investment
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Olivier Bautheac, Daniel Broby, and Andrew M. McKenzie
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Market capitalization ,Index (economics) ,Investment strategy ,Management of Technology and Innovation ,Strategy and Management ,Institutional investor ,Commodity ,Business ,Asset (economics) ,Investment (macroeconomics) ,Futures contract ,Finance ,Industrial organization - Abstract
In this article the authors propose an appropriate commodities benchmark for pension funds. Commodity investment, like traditional investment, requires suitable benchmarks for performance measurement and attribution. Investing in commodities as an asset class has increased dramatically as a result of financialization. It is typically conducted by pension funds through the futures market. The tools to implement and benchmark the success or failure of such an investment strategy are still in their infancy. The authors argue that factor model indexes (FMIs) are a viable alternative to existing production-based indexes that make use of futures contracts. Using principal component analysis, they identify five factors related to grains, meats, industrial metals, energy, and precious metals. They suggest that FMI benchmarks constructed using such an approach would allow commodity investors to better measure their investment objectives. Key Findings ▪ Proposed commodity factor model index (FMI) derived from principal components for use by institutional investors. ▪ The FMI addresses the issue that the market capitalization concept does not make sense when applied to commodities. ▪ The FMI is a viable alternative to existing production-based indexes that make use of futures contracts.
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- 2021
18. Author Correction: Brain Cell Type Specific Gene Expression and Co-expression Network Architectures
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Alexey Kozlenkov, Alexandra B Keenan, Patrizia Casaccia, Mads E. Hauberg, Bin Zhang, John F. Fullard, Andrew M. McKenzie, Stella Dracheva, Minghui Wang, Yasmin L. Hurd, and Panos Roussos
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Genetic Markers ,Male ,Science ,Datasets as Topic ,Brain Cell ,Mice ,Gene expression ,Animals ,Humans ,Gene Regulatory Networks ,Author Correction ,Neurons ,Network architecture ,Multidisciplinary ,Gene Expression Profiling ,Type specific ,Endothelial Cells ,Temporal Lobe ,Cell biology ,Mice, Inbred C57BL ,Expression (architecture) ,Medicine ,Female ,Single-Cell Analysis ,Databases, Nucleic Acid ,Transcriptome ,Neuroglia ,Geology - Abstract
Elucidating brain cell type specific gene expression patterns is critical towards a better understanding of how cell-cell communications may influence brain functions and dysfunctions. We set out to compare and contrast five human and murine cell type-specific transcriptome-wide RNA expression data sets that were generated within the past several years. We defined three measures of brain cell type-relative expression including specificity, enrichment, and absolute expression and identified corresponding consensus brain cell "signatures," which were well conserved across data sets. We validated that the relative expression of top cell type markers are associated with proxies for cell type proportions in bulk RNA expression data from postmortem human brain samples. We further validated novel marker genes using an orthogonal ATAC-seq dataset. We performed multiscale coexpression network analysis of the single cell data sets and identified robust cell-specific gene modules. To facilitate the use of the cell type-specific genes for cell type proportion estimation and deconvolution from bulk brain gene expression data, we developed an R package, BRETIGEA. In summary, we identified a set of novel brain cell consensus signatures and robust networks from the integration of multiple datasets and therefore transcend limitations related to technical issues characteristic of each individual study.
- Published
- 2021
19. Factors affecting the choice of governance structure along the vegetable value chain in Bangladesh
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Dabasis Sharma, Mohammad Jahangir Alam, Ismat Ara Begum, and Andrew M. McKenzie
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governance ,value chain ,General Medicine ,Public Economics ,multinomial logit model - Abstract
Analyzing governance structure is considered important when designing development interventions in the value chain. The objective of this paper was to explore the governance structure (GS) in cauliflower and tomato value chain, specifically the types of GS followed by the farmers and factors behind these choices. The two-stage random sampling procedure was used to collect data from 100 farmers whereas 60 traders were surveyed purposively for this study. Multinomial logit model was used to analyze the factors affecting farmer’s choice of GS. Trader’s perceptions regarding internal and external governance as well as good governance indicators were assessed by utilizing non-parametric test. Cauliflower and tomato farmers were involved in practicing spot market, relational, farmer’s association and outgrowing scheme-based GS. The results showed that the probability to choose relational, outgrowing scheme and farmer’s association-based GS were significantly affected by education of farmers, distance to the nearest market, access to extension services, access to price information, trust commitment, transaction specific investment, preferences of diversification, farm size, transactional uncertainty, and access to producer’s cooperative. Wilcoxon-Mann-Whitney-U test established trader’s dissimilation towards governance indicators. The study suggests that smallholder farmers need to be well organized and coordination mechanisms among all stakeholders should be increased.
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- 2022
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20. How do USDA announcements affect international commodity prices?
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Andrew M. McKenzie and Yangmin Ke
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Economics and Econometrics ,Finance - Published
- 2022
21. The landscape of multiscale transcriptomic networks and key regulators in Parkinson’s disease
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Qi Shen, Yuanxi Zhang, Zhenyu Yue, Won-Min Song, Insup Choi, Ping-Yue Pan, Minghui Wang, Xianxiao Zhou, Bin Zhang, Andrew M. McKenzie, and Qian Wang
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0301 basic medicine ,Parkinson's disease ,Science ,Regulator ,General Physics and Astronomy ,Substantia nigra ,Stathmin ,Biology ,General Biochemistry, Genetics and Molecular Biology ,Article ,Transcriptome ,03 medical and health sciences ,Mice ,0302 clinical medicine ,medicine ,Animals ,Humans ,Gene Regulatory Networks ,Synaptic transmission ,Phosphorylation ,Transcriptomics ,lcsh:Science ,Multidisciplinary ,Dopaminergic Neurons ,Gene Expression Profiling ,Dopaminergic ,Parkinson Disease ,General Chemistry ,medicine.disease ,Regulatory networks ,Gene expression profiling ,Substantia Nigra ,030104 developmental biology ,Gene Knockdown Techniques ,biology.protein ,alpha-Synuclein ,lcsh:Q ,Neuroscience ,030217 neurology & neurosurgery ,Biological network ,Locomotion - Abstract
Genetic and genomic studies have advanced our knowledge of inherited Parkinson’s disease (PD), however, the etiology and pathophysiology of idiopathic PD remain unclear. Herein, we perform a meta-analysis of 8 PD postmortem brain transcriptome studies by employing a multiscale network biology approach to delineate the gene-gene regulatory structures in the substantia nigra and determine key regulators of the PD transcriptomic networks. We identify STMN2, which encodes a stathmin family protein and is down-regulated in PD brains, as a key regulator functionally connected to known PD risk genes. Our network analysis predicts a function of human STMN2 in synaptic trafficking, which is validated in Stmn2-knockdown mouse dopaminergic neurons. Stmn2 reduction in the mouse midbrain causes dopaminergic neuron degeneration, phosphorylated α-synuclein elevation, and locomotor deficits. Our integrative analysis not only begins to elucidate the global landscape of PD transcriptomic networks but also pinpoints potential key regulators of PD pathogenic pathways., Parkinson’s disease (PD) is characterized by neurodegeneration associated with loss of dopaminergic (DA) neurons and deposition of Lewy bodies. Here, Wang et al. use co-expression network analysis to pinpoint disease pathways and propose reduced expression of STMN2 as a cause of presynaptic function loss in PD.
- Published
- 2019
22. Stress resilience is promoted by a Zfp189-driven transcriptional network in prefrontal cortex
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Hope Kronman, Zachary S. Lorsch, Marine Salery, Lyonna F. Parise, Ian Maze, Li Shen, Andrew Conkey, Gustavo Turecki, Yong-Hwee E. Loh, Orna Issler, Ann E. Symonds, Eric J. Nestler, Ashley E. Lepack, Benoit Labonté, Rosemary C. Bagot, Peter J. Hamilton, Stephen T. Pirpinias, Yan Dong, Idelisse Ortiz Torres, Rachael L. Neve, Sarah E. Montgomery, Xianxiao Zhou, Philipp Mews, Eric M. Parise, Aarthi Ramakrishnan, Andrew M. McKenzie, William J. Wright, and Bin Zhang
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0301 basic medicine ,Transcription, Genetic ,Regulator ,Prefrontal Cortex ,Biology ,CREB ,Article ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Transcription (biology) ,Adaptation, Psychological ,Animals ,Gene Regulatory Networks ,Prefrontal cortex ,Gene ,Transcription factor ,Zinc finger ,General Neuroscience ,Zinc Fingers ,Mice, Inbred C57BL ,030104 developmental biology ,Histone methyltransferase ,biology.protein ,Neuroscience ,Stress, Psychological ,030217 neurology & neurosurgery - Abstract
Understanding the transcriptional changes that are engaged in stress resilience may reveal novel antidepressant targets. Here we use gene co-expression analysis of RNA-sequencing data from brains of resilient mice to identify a gene network that is unique to resilience. Zfp189, which encodes a previously unstudied zinc finger protein, is the highest-ranked key driver gene in the network, and overexpression of Zfp189 in prefrontal cortical neurons preferentially activates this network and promotes behavioral resilience. The transcription factor CREB is a predicted upstream regulator of this network and binds to the Zfp189 promoter. To probe CREB-Zfp189 interactions, we employ CRISPR-mediated locus-specific transcriptional reprogramming to direct CREB or G9a (a repressive histone methyltransferase) to the Zfp189 promoter in prefrontal cortex neurons. Induction of Zfp189 with site-specific CREB is pro-resilient, whereas suppressing Zfp189 expression with G9a increases susceptibility. These findings reveal an essential role for Zfp189 and CREB-Zfp189 interactions in mediating a central transcriptional network of resilience.
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- 2019
23. The cost of forward contracting in the Mississippi barge freight river market
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B. Wade Brorsen, Andrew M. McKenzie, and Bradley J. Isbell
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Finance ,Economics and Econometrics ,business.industry ,Risk premium ,Geography, Planning and Development ,BARGE ,Summer season ,Forward contract ,Rest (finance) ,Forward market ,Animal Science and Zoology ,Business ,Agronomy and Crop Science ,Food Science - Abstract
Barges on the Mississippi River system are traded via a forward market. We find that risk premiums to use this market vary by season and in terms of which party bares the cost of forward contracting. During the summer season barge operators pay a risk premium. Yet during the rest of the year, elevator operators pay a premium to lock in rates.
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- 2019
24. THE COST OF FORWARD CONTRACTING IN THE CIF NOLA EXPORT BID MARKET
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Andrew M. McKenzie, Bradley J. Isbell, and B. Wade Brorsen
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Economics and Econometrics ,Risk premium ,05 social sciences ,Futures market ,Monetary economics ,Agricultural and Biological Sciences (miscellaneous) ,Market liquidity ,Forward contract ,Balance (accounting) ,0502 economics and business ,Forward market ,050202 agricultural economics & policy ,Business ,050207 economics - Abstract
The CIF NOLA “river market” represents an important but opaque forward market that serves Gulf exporters and elevators. CIF NOLA bids function similarly to traditional forward contracts; however, like a futures market, firms can offset their forward contractual obligations by offsetting positions in a liquid off-exchange paper market. Analysis shows grain sellers pay a risk premium for fall harvest delivery contracts. However, outside of fall harvest, contract liquidity, coupled with a good institutional balance of long and short market participants, mostly removes the pricing bias commonly found in farmer forward contracting in corn and soybeans.
- Published
- 2019
25. BIN1 Genetic Risk Factor for Alzheimer is Sufficient to Induce Early Structural Tract Alterations in Entorhinal-Hippocampal Area and Memory-Related Hippocampal Multi-Scale Impairments
- Author
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TomoKazu Tsurugizawa, Damien Marechal, Aude-Marie Lepagnol-Bestel, Jean-Christophe Rain, Michel Simonneau, Martina Reiss, Nicolas Bourg, Helin Atas-Ozcan, Alexandra Winkeler, Valerie Hindie, Jocelyn Laporte, Patrick Dutar, Jorge Diaz, Doulaye Dembélé, Guillaume Dupuis, Yoshifumi Abe, Harald Kranz, Maxime Sartori, Denis Le Bihan, Claire Chevalier, Chiara Guerrera, Guillaume Pavlovic, Bernard Malissen, Roxane Golgolab, Luisa Ciobanu, Andrew M. McKenzie, Sandrine Lévêque-Fort, Brigitte Potier, Bin Zhang, Loic Lindner, Joanna Lipecka, Christelle Thibault-Carpentier, Julia Viard, Elisabeth Davenas, Cyril Poupon, Yann Herault, Ivy Uszynski, Marie-Christine Birling, Qing Jun Wang, Rachel Daudin, and Yann Loe-Mie
- Subjects
Genetically modified mouse ,medicine.anatomical_structure ,Dendritic spine ,Gyrus ,Resting state fMRI ,medicine ,Long-term potentiation ,Biology ,Hippocampal formation ,Entorhinal cortex ,Episodic memory ,Neuroscience - Abstract
Genetic factors are known to contribute to Late Onset Alzheimer’s disease (LOAD) but their contribution to pathophysiology, specially to prodomic phases accessible to therapeutic approaches are far to be understood. To translate genetic risk of Alzheimer's disease (AD) into mechanistic insight, we generated transgenic mouse lines that express a ~195 kbp human BAC that includes only BIN1, a gene associated to LOAD. This model gives a modest BIN1 overexpression, dependent of the number of BAC copies. At 6 months of age, we detected impaired entorhinal cortex (EC)-hippocampal pathways with specific impairments in EC-dentate gyrus synaptic long-term potentiation, dendritic spines of granular cells and recognition episodic memory. Structural changes were quantified using MRI. Their whole-brain functional impact were analyzed using resting state fMRI with a hypoconnectivity centered on entorhinal cortex. These early phenotype defects independent of any changes in A-beta can be instrumental in the search for new AD drug targets.
- Published
- 2021
26. Was the Missing 2013 WASDE Missed?
- Author
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Michael K. Adjemian, Michael R. Thomsen, Robert Johansson, and Andrew M. McKenzie
- Subjects
Economics and Econometrics ,0502 economics and business ,05 social sciences ,050202 agricultural economics & policy ,Business ,050207 economics ,Development - Published
- 2017
27. A common haplotype lowers PU.1 expression in myeloid cells and delays onset of Alzheimer's disease
- Author
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Towfique Raj, Sven J. van der Lee, Julie Williams, Anna A. Pimenova, Benjamin Grenier-Boley, Laura Ibanez, Annette L. Fitzpatrick, Jorge L. Del-Aguila, Benjamin P. Fairfax, Gerard D. Schellenberg, Edoardo Marcora, Anita L. DeStefano, Sarah Bertelsen, Hieab H.H. Adams, Manav Kapoor, Valentina Escott-Price, Carlos Cruchaga, Cornelia M. van Duijn, Alan E. Renton, Richard Mayeux, Céline Bellenguez, Jean-Charles Lambert, Lindsay A. Farrer, Vincent Chouraki, Rebecca Sims, Kuan-lin Huang, Margaret A. Pericak-Vance, Bin Zhang, M. Arfan Ikram, Antonio Fabio Di Narzo, Maria Victoria Fernandez, Philippe Amouyel, Alison Goate, Ingrid B. Borecki, Sheng Chih Jin, Albert V. Smith, Yuetiva Deming, Joshua C. Bis, Jonathan L. Haines, Andrew M. McKenzie, Sudha Seshadri, Lenore J. Launer, John S. K. Kauwe, Oscar Harari, Jake Czajkowski, Ke Hao, John P. Budde, and Epidemiology
- Subjects
0301 basic medicine ,Male ,Linkage disequilibrium ,Myeloid ,Locus (genetics) ,Biology ,Polymorphism, Single Nucleotide ,Linkage Disequilibrium ,Article ,03 medical and health sciences ,Mice ,Alzheimer Disease ,Risk Factors ,Proto-Oncogene Proteins ,Gene expression ,medicine ,Animals ,Humans ,Genetic Predisposition to Disease ,Allele ,Gene ,Alleles ,SPI1 ,General Neuroscience ,030104 developmental biology ,medicine.anatomical_structure ,Cistrome ,Haplotypes ,Immunology ,Cancer research ,Trans-Activators ,Female ,Genome-Wide Association Study ,Transcription Factors - Abstract
A genome-wide survival analysis of 14,406 Alzheimer's disease (AD) cases and 25,849 controls identified eight previously reported AD risk loci and 14 novel loci associated with age at onset. Linkage disequilibrium score regression of 220 cell types implicated the regulation of myeloid gene expression in AD risk. The minor allele of rs1057233 (G), within the previously reported CELF1 AD risk locus, showed association with delayed AD onset and lower expression of SPI1 in monocytes and macrophages. SPI1 encodes PU.1, a transcription factor critical for myeloid cell development and function. AD heritability was enriched within the PU.1 cistrome, implicating a myeloid PU.1 target gene network in AD. Finally, experimentally altered PU.1 levels affected the expression of mouse orthologs of many AD risk genes and the phagocytic activity of mouse microglial cells. Our results suggest that lower SPI1 expression reduces AD risk by regulating myeloid gene expression and cell function.
- Published
- 2017
28. Perfusion fixation in brain banking: a systematic review
- Author
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John F. Crary, Clare Bryce, Mary Fowkes, Felix Richter, Hadley Walsh, Andrew M. McKenzie, Patrick R. Hof, Celine Soudant, and Whitney C. McFadden
- Subjects
0301 basic medicine ,Connectomics ,Tissue Fixation ,Perfusion fixation ,Moderate confidence ,Perfusion scanning ,Tissue Banks ,Review ,lcsh:RC346-429 ,Pathology and Forensic Medicine ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,Brain perfusion ,medicine ,Humans ,lcsh:Neurology. Diseases of the nervous system ,Fixation (histology) ,business.industry ,Brain ,Tissue Processing ,Human brain ,Brain banking ,3. Good health ,Perfusion ,Immersion fixation ,030104 developmental biology ,medicine.anatomical_structure ,Histology quality ,Neurology (clinical) ,Nuclear medicine ,business ,030217 neurology & neurosurgery ,Large animal - Abstract
Background Perfusing fixatives through the cerebrovascular system is the gold standard approach in animals to prepare brain tissue for spatial biomolecular profiling, circuit tracing, and ultrastructural studies such as connectomics. Translating these discoveries to humans requires examination of postmortem autopsy brain tissue. Yet banked brain tissue is routinely prepared using immersion fixation, which is a significant barrier to optimal preservation of tissue architecture. The challenges involved in adopting perfusion fixation in brain banks and the extent to which it improves histology quality are not well defined. Methodology We searched four databases to identify studies that have performed perfusion fixation in human brain tissue and screened the references of the eligible studies to identify further studies. From the included studies, we extracted data about the methods that they used, as well as any data comparing perfusion fixation to immersion fixation. The protocol was preregistered at the Open Science Framework: https://osf.io/cv3ys/. Results We screened 4489 abstracts, 214 full-text publications, and identified 35 studies that met our inclusion criteria, which collectively reported on the perfusion fixation of 558 human brains. We identified a wide variety of approaches to perfusion fixation, including perfusion fixation of the brain in situ and ex situ, perfusion fixation through different sets of blood vessels, and perfusion fixation with different washout solutions, fixatives, perfusion pressures, and postfixation tissue processing methods. Through a qualitative synthesis of data comparing the outcomes of perfusion and immersion fixation, we found moderate confidence evidence showing that perfusion fixation results in equal or greater subjective histology quality compared to immersion fixation of relatively large volumes of brain tissue, in an equal or shorter amount of time. Conclusions This manuscript serves as a resource for investigators interested in building upon the methods and results of previous research in designing their own perfusion fixation studies in human brains or other large animal brains. We also suggest several future research directions, such as comparing the in situ and ex situ approaches to perfusion fixation, studying the efficacy of different washout solutions, and elucidating the types of brain donors in which perfusion fixation is likely to result in higher fixation quality than immersion fixation. Electronic supplementary material The online version of this article (10.1186/s40478-019-0799-y) contains supplementary material, which is available to authorized users.
- Published
- 2019
29. The innate immunity protein IFITM3 modulates γ-secretase in Alzheimer's disease
- Author
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Pengju Nie, Katherine R. Sadleir, Yujia Zhai, Bianca T. Esposito, Andrew M. McKenzie, Christina J. Crump, Eitan Wong, Douglas S. Johnson, Julia Tcw, Eliezer Masliah, Ji-Yeun Hur, Paul Greengard, Yotam Sagi, Chen Ming, Yong Kim, Jen Chyong Wang, Si Jia Pan, Marília A. S. Barros, Bin Zhang, Xianzhong Wu, Robert A. Rissman, Lei Guo, Thomas Li, Georgia R. Frost, Yue-Ming Li, Alison Goate, Minghui Wang, Robert Vassar, Xianxiao Zhou, Ivy Trinh, and Alan E. Renton
- Subjects
0301 basic medicine ,Male ,Aging ,Amyloid plaques ,Amyloid beta-Protein Precursor ,Mice ,0302 clinical medicine ,Catalytic Domain ,Γ-secretase ,Age of Onset ,Aged, 80 and over ,Innate immunity ,Multidisciplinary ,RNA-Binding Proteins ,Transmembrane protein ,Cell biology ,Up-Regulation ,IFITM3 ,Female ,medicine.symptom ,Alzheimer’s disease ,Genetically modified mouse ,Risk ,Inflammation ,Mice, Transgenic ,Biology ,Photo-crosslinking ,Interferon-induced transmembrane protein ,Article ,Presenilin ,Proinflammatory cytokine ,03 medical and health sciences ,Immunity ,Alzheimer Disease ,Nicastrin ,medicine ,Presenilin-1 ,Animals ,Humans ,Neuroinflammation ,Innate immune system ,Membrane Proteins ,Immunity, Innate ,Mice, Inbred C57BL ,Disease Models, Animal ,030104 developmental biology ,HEK293 Cells ,Astrocytes ,Commentary ,Interferons ,Amyloid Precursor Protein Secretases ,030217 neurology & neurosurgery - Abstract
Innate immunity is associated with Alzheimer’s disease1, but the influence of immune activation on the production of amyloid-β is unknown2,3. Here we identify interferon-induced transmembrane protein 3 (IFITM3) as a γ-secretase modulatory protein, and establish a mechanism by which inflammation affects the generation of amyloid-β. Inflammatory cytokines induce the expression of IFITM3 in neurons and astrocytes, which binds to γ-secretase and upregulates its activity, thereby increasing the production of amyloid-β. The expression of IFITM3 is increased with ageing and in mouse models that express familial Alzheimer’s disease genes. Furthermore, knockout of IFITM3 reduces γ-secretase activity and the formation of amyloid plaques in a transgenic mouse model (5xFAD) of early amyloid deposition. IFITM3 protein is upregulated in tissue samples from a subset of patients with late-onset Alzheimer’s disease that exhibit higher γ-secretase activity. The amount of IFITM3 in the γ-secretase complex has a strong and positive correlation with γ-secretase activity in samples from patients with late-onset Alzheimer’s disease. These findings reveal a mechanism in which γ-secretase is modulated by neuroinflammation via IFITM3 and the risk of Alzheimer’s disease is thereby increased. The IFITM3 innate immunity protein directly binds presenilin near the active site and upregulates γ-secretase activity and the production of amyloid-β, and IFITM3 is upregulated in patients with late-onset Alzheimer’s disease.
- Published
- 2019
30. Risk Transmission between Chinese and U.S. Agricultural Commodity Futures Markets—A CoVaR Approach
- Author
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Yangmin Ke, Ping Liu, Chongguang Li, and Andrew M. McKenzie
- Subjects
China ,Financial economics ,media_common.quotation_subject ,Geography, Planning and Development ,lcsh:TJ807-830 ,Downside risk ,lcsh:Renewable energy sources ,Public policy ,Management, Monitoring, Policy and Law ,Price discovery ,0502 economics and business ,agricultural commodity futures markets ,050207 economics ,Risk management ,health care economics and organizations ,lcsh:Environmental sciences ,media_common ,CoVaR ,lcsh:GE1-350 ,050208 finance ,Renewable Energy, Sustainability and the Environment ,business.industry ,lcsh:Environmental effects of industries and plants ,05 social sciences ,risk transmission ,Expected shortfall ,lcsh:TD194-195 ,Cash ,business ,Futures contract - Abstract
Commodity futures markets play an important role, through risk management and price discovery, in helping firms make sustainable production and marketing decisions. An important related issue is how pricing signals between futures exchanges impact traders&rsquo, risk. We address this issue by shedding light on risk transmission between the most mature (U.S.) and the fastest growing (Chinese) commodity futures markets. Gaining greater insight of risk transmission between these key markets is vitally important to firms engaged in the efficient and sustainable trade of commodities needed to feed the world. We examine the risk transmission between Chinese and U.S. agricultural futures markets for soybean, corn, and sugar with a Copula based conditional value at risk (CoVaR) approach. We find significant upside, and to a lesser extent downside risk transmission, between Chinese and U.S. markets. We confirm the dominant pricing role of U.S. agricultural futures markets while acknowledging the increasing price discovery role performed by Chinese markets. Our results highlight that soybean markets exhibit greater risk transmission than sugar and corn markets. We argue that our findings may be explained by Chinese government policy intervention, and by the large role played by U.S. firms in the underlying cash commodity markets&ndash, both in terms of production and trade.
- Published
- 2019
31. Asymmetry Price Transmission in the Deregulated Rice Markets in Bangladesh: Asymmetric Error Correction Model
- Author
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Mohammad Jahangir Alam, Guido Van Huylenbroeck, Jeroen Buysse, Ismat Ara Begum, Eric J. Wailes, and Andrew M. McKenzie
- Subjects
Wholesale price index ,Economics and Econometrics ,Producer Price Index (India) ,05 social sciences ,Geography, Planning and Development ,Mid price ,Price discovery ,Asymmetric price transmission ,Microeconomics ,Reservation price ,0502 economics and business ,Econometrics ,Economics ,Animal Science and Zoology ,Price level ,050202 agricultural economics & policy ,050207 economics ,Agronomy and Crop Science ,Limit price ,Food Science - Abstract
There is a widely held belief among public consumers that rice prices are manipulated in Bangladesh. This manipulation may have led to price asymmetry in the vertical chain of Bangladesh rice markets. This paper is an attempt to investigate the existence of asymmetry between wholesale and retail rice prices in Bangladesh. Maximum likelihood estimation (MLE) based cointegration test was applied to determine long-run equilibrium relationship. We examine whether the wholesale market dominates the retail market—in terms of price discovery and price leadership—or vice versa. Finally, we analyze whether the wholesale-retail price relationship is asymmetric with respect to price increases and price decreases. To test the asymmetric price transmission we used the asymmetric error correction-EG approach. Our results show that wholesale and retail prices are cointegrated, and wholesale market plays a leadership role in determining retail prices, which is in line with industrial organization theory. Our results confirm the fear and concerns of consumers about the existence of price asymmetry. [JEL Classification: Q110; Q113].
- Published
- 2016
32. BIN1 genetic risk factor for Alzheimer is sufficient to induce early structural tract alterations in entorhinal-hippocampal area and memory-related hippocampal multi-scale impairments
- Author
-
Marie-Christine Birling, Y Abe, Jean-Christophe Rain, Martina Reiss, Maxime Sartori, I. Uszynski, Christelle Thibault-Carpentier, Alexandra Winkeler, Julia Viard, Andrew M. McKenzie, D Le Bihan, Bernard Malissen, Harald Kranz, Damien Marechal, Guillaume Dupuis, Cyril Poupon, Aude-Marie Lepagnol-Bestel, R Golgolab, Yann Loe-Mie, Chiara Guerrera, Helin Atas-Ozcan, B Potier, Valerie Hindie, Jocelyn Laporte, Luisa Ciobanu, Jorge Diaz, Guillaume Pavlovic, R Daudin, Yann Herault, Loic Lindner, Joanna Lipecka, Tomokazu Tsurugizawa, Sandrine Lévêque-Fort, Qing Jun Wang, Elisabeth Davenas, Doulaye Dembélé, Claire Chevalier, P. Dutar, Michel Simonneau, Bin Zhang, and Nathalie Bourg
- Subjects
Apolipoprotein E ,0303 health sciences ,Neurodegeneration ,Long-term potentiation ,Hippocampal formation ,Biology ,medicine.disease ,Somatosensory system ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Gyrus ,medicine ,Dementia ,Neuroscience ,Episodic memory ,030217 neurology & neurosurgery ,030304 developmental biology - Abstract
Late Onset Alzheimer Disease (LOAD) is the most common form of dementia and one of the most challenging diseases of modern society. Understanding the preclinical stages of AD that begins in the brain at least 2 to 3 decades before evidence of episodic memory defects in patients is pivotal for the design of successful approaches to delay or reverse the transition from normal brain function to cognitive impairments. Our working hypothesis is that LOAD genetic risk factors can be sufficient to generate early phenotypical changes before any changes in either Abeta or Tau. To test this hypothesis, we generated an hBIN1 mouse model based on the human BIN1 gene overexpression that we found in post-mortem brain samples from LOAD patients. BIN1 is the second important risk factor for AD, following the APOE gene. We identified co-deregulated gene repertoires common to both 7-week mouse hippocampus sub-regions and post-mortem brain samples from LOAD patients, demonstrating the validity of this hBIN1 model. We evidenced an early phenotype of neurodegeneration starting at 3 months with structural impairment fiber pathways quantified by high resolution (17.2T) (MRI DTI) and related functional impacts. We found structural changes in entorhinal cortex-dentate gyrus (EC-DG) pathway known to be the earliest brain region impacted in LOAD. Similarly, the function of this pathway was impaired both in vitro and in vivo, with the changes in spine density and dendritic simplification of DG neurons, impaired EC-DG long-term potentiation (LTP) and behavioral deficits linked to object recognition episodic memory. As expected for a neurodegenerative model, we evidenced the progression of dysfunction at the morphological, functional and behavioral levels with age. Structural spreading involved impairment of fibers in somatosensory and temporal associative cortexes at month 15. Functional and behavioral spreading was characterized by impact on pattern separation of spatial episodic memory. Moreover, this neurodegeneration occurred without any detectable changes in Abeta 1-42 and tau. Overall, these data show the possibility to identify a repertoire of molecular changes occurring both in patients and in hBIN1 mice and whose further manipulation can be instrumental to rescue or delay episodic memory defects.
- Published
- 2018
33. Zfp189 Mediates Stress Resilience Through a CREB-Regulated Transcriptional Network in Prefrontal Cortex
- Author
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Xianxiao Zhou, Peter J. Hamilton, Rosemary C. Bagot, Benoit Labonté, Idelisse Ortiz Torres, Eric J. Nestler, Andrew M. McKenzie, Zachary S. Lorsch, Ian Maze, Conkey A, Lyonna F. Parise, Rachel L. Neve, Sarah E. Montgomery, Marine Salery, Orna Issler, Bin Zhang, Eric M. Parise, Aarthi Ramakrishnan, Philipp Mews, William J. Wright, Gustavo Turecki, Ann E. Symonds, Stephen T. Pirpinias, Yan Dong, Li Shen, Ashley E. Lepack, and Yong-Hwee E. Loh
- Subjects
Zinc finger ,Transcriptome ,biology ,Gene regulatory network ,biology.protein ,Regulator ,Premovement neuronal activity ,Resilience (network) ,CREB ,Prefrontal cortex ,Neuroscience - Abstract
SummaryStress resilience involves numerous brain-wide transcriptional changes. Determining the organization and orchestration of these transcriptional events may reveal novel antidepressant targets, but this remains unexplored. Here, we characterize the resilient transcriptome with co-expression analysis and identify a single transcriptionally-active uniquely-resilient gene network. Zfp189, a previously unstudied zinc finger protein, is the top network key driver and its overexpression in prefrontal cortical (PFC) neurons preferentially activates this network, alters neuronal activity and promotes behavioral resilience. CREB, which binds Zfp189, is the top upstream regulator of this network. To probe CREB-Zfp189 interactions as a network regulatory mechanism, we employ CRISPR-mediated locus-specific transcriptional reprogramming to direct CREB selectively to the Zfp189 promoter. This single molecular interaction in PFC neurons recapitulates the pro-resilient Zfp189-dependent downstream effects on gene network activity, electrophysiology and behavior. These findings reveal an essential role for Zfp189 and a CREB-Zfp189 regulatory axis in mediating a central transcriptional network of resilience.
- Published
- 2018
34. Brain Cell Type Specific Gene Expression and Co-expression Network Architectures
- Author
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Mads E. Hauberg, Panos Roussos, Patrizia Casaccia, Alexey Kozlenkov, Yasmin L. Hurd, John F. Fullard, Minghui Wang, Andrew M. McKenzie, Stella Dracheva, Alexandra B Keenan, and Bin Zhang
- Subjects
0301 basic medicine ,Cell type ,Science ,Cell ,DIVERSITY ,Gene regulatory network ,Computational biology ,Biology ,ASTROCYTES ,MICROGLIA ,Transcriptome ,03 medical and health sciences ,Single-cell analysis ,Gene expression ,medicine ,RNA-SEQ ,TRANSCRIPTOME ,DNA METHYLATION ,Gene ,Multidisciplinary ,CENTRAL-NERVOUS-SYSTEM ,ALZHEIMERS-DISEASE ,Gene expression profiling ,030104 developmental biology ,medicine.anatomical_structure ,Medicine ,STEM-CELLS ,RESPONSES - Abstract
Elucidating brain cell type specific gene expression patterns is critical towards a better understanding of how cell-cell communications may influence brain functions and dysfunctions. We set out to compare and contrast five human and murine cell type-specific transcriptome-wide RNA expression data sets that were generated within the past several years. We defined three measures of brain cell type-relative expression including specificity, enrichment, and absolute expression and identified corresponding consensus brain cell “signatures,” which were well conserved across data sets. We validated that the relative expression of top cell type markers are associated with proxies for cell type proportions in bulk RNA expression data from postmortem human brain samples. We further validated novel marker genes using an orthogonal ATAC-seq dataset. We performed multiscale coexpression network analysis of the single cell data sets and identified robust cell-specific gene modules. To facilitate the use of the cell type-specific genes for cell type proportion estimation and deconvolution from bulk brain gene expression data, we developed an R package, BRETIGEA. In summary, we identified a set of novel brain cell consensus signatures and robust networks from the integration of multiple datasets and therefore transcend limitations related to technical issues characteristic of each individual study.
- Published
- 2018
35. Multiscale network modeling of oligodendrocytes reveals molecular components of myelin dysregulation in Alzheimer’s disease
- Author
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Joshua D. Aaker, Patrizia Casaccia, Brian Popko, Eric E. Schadt, Sarah Moyon, Noam D. Beckmann, James J. Lah, Pei Wang, Eric B. Dammer, Pavel Katsel, Yongzhong Zhao, Duc M. Duong, Bin Zhang, Allan I. Levey, Andrew M. McKenzie, Vahram Haroutunian, Won-Min Song, Minghui Wang, Igor Katsyv, Nicholas T. Seyfried, Xianxiao Zhou, Jun Zhu, and Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, 1470 Madison Avenue, New York, NY 10029, USA
- Subjects
0301 basic medicine ,Proteomics ,BIN1 ,[SDV]Life Sciences [q-bio] ,Models, Neurological ,Gene regulatory network ,lcsh:Geriatrics ,Biology ,lcsh:RC346-429 ,Mice ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,Myelin ,UGT8 ,Differential expression ,Alzheimer Disease ,Gene expression ,medicine ,Animals ,Humans ,Gene Regulatory Networks ,Molecular Biology ,Gene ,lcsh:Neurology. Diseases of the nervous system ,Myelin Sheath ,co-expression network ,Gene Expression Profiling ,Neurodegeneration ,RNA sequencing ,Alzheimer's disease ,medicine.disease ,Major gene ,Oligodendrocyte ,lcsh:RC952-954.6 ,Oligodendroglia ,030104 developmental biology ,medicine.anatomical_structure ,Causal network ,CNP ,Neurology (clinical) ,Alzheimer’s disease ,Neuroscience ,Research Article - Abstract
Background Oligodendrocytes (OLs) and myelin are critical for normal brain function and have been implicated in neurodegeneration. Several lines of evidence including neuroimaging and neuropathological data suggest that Alzheimer’s disease (AD) may be associated with dysmyelination and a breakdown of OL-axon communication. Methods In order to understand this phenomenon on a molecular level, we systematically interrogated OL-enriched gene networks constructed from large-scale genomic, transcriptomic and proteomic data obtained from human AD postmortem brain samples. We then validated these networks using gene expression datasets generated from mice with ablation of major gene expression nodes identified in our AD-dysregulated networks. Results The robust OL gene coexpression networks that we identified were highly enriched for genes associated with AD risk variants, such as BIN1 and demonstrated strong dysregulation in AD. We further corroborated the structure of the corresponding gene causal networks using datasets generated from the brain of mice with ablation of key network drivers, such as UGT8, CNP and PLP1, which were identified from human AD brain data. Further, we found that mice with genetic ablations of Cnp mimicked aspects of myelin and mitochondrial gene expression dysregulation seen in brain samples from patients with AD, including decreased protein expression of BIN1 and GOT2. Conclusions This study provides a molecular blueprint of the dysregulation of gene expression networks of OL in AD and identifies key OL- and myelination-related genes and networks that are highly associated with AD. Electronic supplementary material The online version of this article (10.1186/s13024-017-0219-3) contains supplementary material, which is available to authorized users.
- Published
- 2017
36. Low-Frequency Volatility in China’s Gold Futures Market and Its Macroeconomic Determinants
- Author
-
Tingfei Tang, Yibin Liu, Andrew M. McKenzie, and Song Liu
- Subjects
Article Subject ,lcsh:Mathematics ,General Mathematics ,General Engineering ,Futures market ,Monetary economics ,Implied volatility ,lcsh:QA1-939 ,Volatility risk premium ,lcsh:TA1-2040 ,Volatility swap ,Volatility smile ,Forward volatility ,Economics ,Volatility (finance) ,lcsh:Engineering (General). Civil engineering (General) ,China - Abstract
We extract low- and high-frequency volatility from China’s Shanghai gold futures market using an asymmetric Spline-GARCH (ASP-GARCH) model. We then regress monthly low-frequency volatility on selected monthly macroeconomic indicators to study the impact of macroeconomy on gold futures market and to test for excess volatility. Our main result is volatility in China’s Shanghai gold futures market resulting from both macroeconomic fluctuations and investor behaviour. Chinese Consumer Price Index Volatility and US dollar volatility are the two main determinants of low-frequency gold volatility. We also find significant evidence of excess volatility, which can in part be explained in terms of loss-aversive investor behaviour.
- Published
- 2015
37. A common haplotype lowers PU.1 expression in myeloid cells and delays onset of Alzheimer’s disease
- Author
-
Julie Williams, Jonathan L. Haines, Jean-Charles Lambert, Anna A. Pimenova, M. Arfan Ikram, Antonio Fabio Di Narzo, Kuan-lin Huang, Laura Ibanez, Alison Goate, Anita L. DeStefano, Ingrid B. Borecki, Hieab H.H. Adams, Alan E. Renton, Jake Czajkowski, Cornelia M. van Duijn, Vincent Chouraki, Ke Hao, Yuetiva Deming, Philippe Amouyel, Lindsay A. Farrer, Towfique Raj, John P. Budde, Richard Mayeux, Céline Bellenguez, Lenore J. Launer, Benjamin Grenier-Boley, Sven J. van der Lee, Joshua C. Bis, Jorge L. Del-Aguila, Andrew M. McKenzie, Albert V. Smith, Manav Kapoor, Sheng Chih Jin, Edoardo Marcora, Rebecca Sims, Oscar Harari, Gerard D. Schellenberg, Bin Zhang, Carlos Cruchaga, John S. K. Kauwe, Maria Victoria Fernandez, Margaret A. Pericak-Vance, Benjamin P. Fairfax, Annette L. Fitzpatrick, Sudha Seshadri, Sarah Bertelsen, and Valentina Escott-Price
- Subjects
0303 health sciences ,Cell type ,SPI1 ,Myeloid ,Locus (genetics) ,Biology ,Minor allele frequency ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Cistrome ,Gene expression ,Immunology ,medicine ,Gene ,030217 neurology & neurosurgery ,030304 developmental biology - Abstract
A genome-wide survival analysis of 14,406 Alzheimer’s disease (AD) cases and 25,849 controls identified eight previously reported AD risk loci and fourteen novel loci associated with age at onset. LD score regression of 220 cell types implicated regulation of myeloid gene expression in AD risk. In particular, the minor allele of rs1057233 (G), within the previously reported CELF1 AD risk locus, showed association with delayed AD onset and lower expression of SPI1 in monocytes and macrophages. SPI1 encodes PU.1, a transcription factor critical for myeloid cell development and function. AD heritability is enriched within the PU.1 cistrome, implicating a myeloid PU.1 target gene network in AD. Finally, experimentally altered PU.1 levels affect the expression of mouse orthologs of many AD risk genes and the phagocytic activity of mouse microglial cells. Our results suggest that lower SPI1 expression reduces AD risk by regulating myeloid gene expression and cell function.
- Published
- 2017
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38. Crude oil–corn–ethanol – nexus: A contextual approach
- Author
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Guido Van Huylenbroeck, Andrew M. McKenzie, and Valeri Natanelov
- Subjects
Corn ethanol ,business.industry ,Financial market ,food and beverages ,Context (language use) ,Management, Monitoring, Policy and Law ,Agricultural economics ,Renewable energy ,Microeconomics ,General Energy ,Biofuel ,Bioenergy ,Economics ,Ethanol fuel ,Volatility (finance) ,business ,health care economics and organizations - Abstract
This paper offers a holistic study on the complex relationships between crude oil, corn and ethanol during a turbulent period between 2006 and end of 2011. Through a holistic mapping of the current market situation and a contextual analytical design we show that there exists a strong relationship between crude oil and corn markets on one side, and crude oil and ethanol on the other. However, the price relationship between corn and ethanol was revealed to be less straightforward, and is driven by the US government fuel policy. Furthermore the study indicates that corn markets have became more prone to volatility due to ethanol production, especially when the demand for corn is high and/or the crude oil prices are high enough to create a competitive market for ethanol.
- Published
- 2013
39. Was there a peso problem in cattle options?
- Author
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Gabriel J. Power, Michael R. Thomsen, and Andrew M. McKenzie
- Subjects
Actuarial science ,Financial economics ,Bovine spongiform encephalopathy ,Economics, Econometrics and Finance (miscellaneous) ,Market data ,Economics ,medicine ,Volatility (finance) ,medicine.disease ,Agricultural and Biological Sciences (miscellaneous) ,Futures contract - Abstract
Purpose – Pricing densities implied from options on live cattle futures show a persistent and negative skew. The purpose is to examine whether the skew can be explained, in part, by peso-type problems. Design/methodology/approach – Two announcements of bovine spongiform encephalopathy (BSE) provide a natural setting within which to examine the validity of the peso-problem explanation. These announcements represent the first documented cases of BSE in North America. Prior to the announcements, the potential for BSE would have been known by market participants as the disease had been found among cattle in the British Isles, Europe and Asia. The paper uses options market data to compute implied moments of the pricing distribution for live cattle futures. The paper then analyzes these moments around BSE announcements. Findings – The first Canadian BSE announcement impacted the mean and volatility but not the implied skew. Later in the year, BSE was found in a US cow and the paper finds a statistically significant change in the implied skew. The distribution showed a pronounced leftward skew prior to the US announcement but was nearly symmetric during the days afterwards. This finding is consistent with the market having priced the possibility of a BSE discovery into deep out-of-the-money put options. Originality/value – Peso problems have been documented in other financial markets. The results are important because they suggest that they may also be important to agricultural markets and that agricultural options markets do account for low probability but highly important events.
- Published
- 2013
40. Leveraging Social Networks for Toxicovigilance
- Author
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Michael Chary, Nicholas Genes, Andrew M. McKenzie, and Alex F. Manini
- Subjects
Substance-Related Disorders ,Health, Toxicology and Mutagenesis ,Drug-Seeking Behavior ,Models, Psychological ,Toxicology ,Social Networking ,Drug Users ,Pharmacovigilance ,Social support ,Artificial Intelligence ,medicine ,Humans ,Social media ,Structure (mathematical logic) ,Illicit Drugs ,business.industry ,Preliminary Research ,Social Support ,Bayes Theorem ,Linguistics ,medicine.disease ,Data science ,United States ,Substance Abuse Detection ,Substance abuse ,The Internet ,Computational linguistics ,Psychology ,business ,Social Media ,Social psychology - Abstract
The landscape of drug abuse is shifting. Traditional means of characterizing these changes, such as national surveys or voluntary reporting by frontline clinicians, can miss changes in usage the emergence of novel drugs. Delays in detecting novel drug usage patterns make it difficult to evaluate public policy aimed at altering drug abuse. Increasingly, newer methods to inform frontline providers to recognize symptoms associated with novel drugs or methods of administration are needed. The growth of social networks may address this need. The objective of this manuscript is to introduce tools for using data from social networks to characterize drug abuse. We outline a structured approach to analyze social media in order to capture emerging trends in drug abuse by applying powerful methods from artificial intelligence, computational linguistics, graph theory, and agent-based modeling. First, we describe how to obtain data from social networks such as Twitter using publicly available automated programmatic interfaces. Then, we discuss how to use artificial intelligence techniques to extract content useful for purposes of toxicovigilance. This filtered content can be employed to generate real-time maps of drug usage across geographical regions. Beyond describing the real-time epidemiology of drug abuse, techniques from computational linguistics can uncover ways that drug discussions differ from other online conversations. Next, graph theory can elucidate the structure of networks discussing drug abuse, helping us learn what online interactions promote drug abuse and whether these interactions differ among drugs. Finally, agent-based modeling relates online interactions to psychological archetypes, providing a link between epidemiology and behavior. An analysis of social media discussions about drug abuse patterns with computational linguistics, graph theory, and agent-based modeling permits the real-time monitoring and characterization of trends of drugs of abuse. These tools provide a powerful complement to existing methods of toxicovigilance.
- Published
- 2013
41. DGCA: A comprehensive R package for Differential Gene Correlation Analysis
- Author
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Won-Min Song, Minghui Wang, Andrew M. McKenzie, Igor Katsyv, and Bin Zhang
- Subjects
0301 basic medicine ,Theoretical computer science ,Computer science ,Systems biology ,Triple Negative Breast Neoplasms ,RNA-Seq ,Computational biology ,Multiscale clustering analysis ,Correlation ,Differential correlation ,Differential coexpression ,03 medical and health sciences ,Breast cancer ,Structural Biology ,Modelling and Simulation ,Humans ,Triple negative breast cancer ,TP53 ,Cluster analysis ,Molecular Biology ,Parametric statistics ,Gene Expression Profiling ,Applied Mathematics ,R package ,PTEN Phosphohydrolase ,Computational Biology ,3. Good health ,Computer Science Applications ,Gene expression profiling ,Identification (information) ,030104 developmental biology ,Receptors, Estrogen ,Modeling and Simulation ,Mutation ,Tumor Suppressor Protein p53 ,Software ,Differential (mathematics) ,Research Article - Abstract
Background Dissecting the regulatory relationships between genes is a critical step towards building accurate predictive models of biological systems. A powerful approach towards this end is to systematically study the differences in correlation between gene pairs in more than one distinct condition. Results In this study we develop an R package, DGCA (for Differential Gene Correlation Analysis), which offers a suite of tools for computing and analyzing differential correlations between gene pairs across multiple conditions. To minimize parametric assumptions, DGCA computes empirical p-values via permutation testing. To understand differential correlations at a systems level, DGCA performs higher-order analyses such as measuring the average difference in correlation and multiscale clustering analysis of differential correlation networks. Through a simulation study, we show that the straightforward z-score based method that DGCA employs significantly outperforms the existing alternative methods for calculating differential correlation. Application of DGCA to the TCGA RNA-seq data in breast cancer not only identifies key changes in the regulatory relationships between TP53 and PTEN and their target genes in the presence of inactivating mutations, but also reveals an immune-related differential correlation module that is specific to triple negative breast cancer (TNBC). Conclusions DGCA is an R package for systematically assessing the difference in gene-gene regulatory relationships under different conditions. This user-friendly, effective, and comprehensive software tool will greatly facilitate the application of differential correlation analysis in many biological studies and thus will help identification of novel signaling pathways, biomarkers, and targets in complex biological systems and diseases. Electronic supplementary material The online version of this article (doi:10.1186/s12918-016-0349-1) contains supplementary material, which is available to authorized users.
- Published
- 2016
42. Integrative network analysis of nineteen brain regions identifies molecular signatures and networks underlying selective regional vulnerability to Alzheimer’s disease
- Author
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Eric E. Schadt, Patrizia Casaccia, Yuji Kajiwara, Alison Goate, John F. Crary, Joseph D. Buxbaum, Sam Gandy, Michelle E. Ehrlich, Xianxiao Zhou, Pavel Katsel, Kristen J. Brennand, Gabriele C. De Luca, Bin Zhang, Minghui Wang, Andrew M. McKenzie, Panos Roussos, and Vahram Haroutunian
- Subjects
0301 basic medicine ,Genetic Markers ,Gene co-expression network ,lcsh:QH426-470 ,Transcription, Genetic ,lcsh:Medicine ,Neuropathology ,Selective vulnerability ,Biology ,Bioinformatics ,Severity of Illness Index ,Cohort Studies ,03 medical and health sciences ,Differential expression ,Alzheimer Disease ,Genetics ,medicine ,Dementia ,Brain cell types ,Humans ,Genetics(clinical) ,Gene Regulatory Networks ,Genetic Predisposition to Disease ,Molecular Biology ,Genetics (clinical) ,Regulation of gene expression ,Gene module ,Research ,Gene Expression Profiling ,lcsh:R ,Brain ,Human brain ,medicine.disease ,Actin cytoskeleton ,Gene expression profiling ,lcsh:Genetics ,030104 developmental biology ,medicine.anatomical_structure ,Gene Expression Regulation ,Molecular Medicine ,Alzheimer's disease ,Demyelination ,Systems biology ,Neuroscience ,Alzheimer’s disease - Abstract
Background Alzheimer’s disease (AD) is the most common form of dementia, characterized by progressive cognitive impairment and neurodegeneration. However, despite extensive clinical and genomic studies, the molecular basis of AD development and progression remains elusive. Methods To elucidate molecular systems associated with AD, we developed a large scale gene expression dataset from 1053 postmortem brain samples across 19 cortical regions of 125 individuals with a severity spectrum of dementia and neuropathology of AD. We excluded brain specimens that evidenced neuropathology other than that characteristic of AD. For the first time, we performed a pan-cortical brain region genomic analysis, characterizing the gene expression changes associated with a measure of dementia severity and multiple measures of the severity of neuropathological lesions associated with AD (neuritic plaques and neurofibrillary tangles) and constructing region-specific co-expression networks. We rank-ordered 44,692 gene probesets, 1558 co-expressed gene modules and 19 brain regions based upon their association with the disease traits. Results The neurobiological pathways identified through these analyses included actin cytoskeleton, axon guidance, and nervous system development. Using public human brain single-cell RNA-sequencing data, we computed brain cell type-specific marker genes for human and determined that many of the abnormally expressed gene signatures and network modules were specific to oligodendrocytes, astrocytes, and neurons. Analysis based on disease severity suggested that: many of the gene expression changes, including those of oligodendrocytes, occurred early in the progression of disease, making them potential translational/treatment development targets and unlikely to be mere bystander result of degeneration; several modules were closely linked to cognitive compromise with lesser association with traditional measures of neuropathology. The brain regional analyses identified temporal lobe gyri as sites associated with the greatest and earliest gene expression abnormalities. Conclusions This transcriptomic network analysis of 19 brain regions provides a comprehensive assessment of the critical molecular pathways associated with AD pathology and offers new insights into molecular mechanisms underlying selective regional vulnerability to AD at different stages of the progression of cognitive compromise and development of the canonical neuropathological lesions of AD. Electronic supplementary material The online version of this article (doi:10.1186/s13073-016-0355-3) contains supplementary material, which is available to authorized users.
- Published
- 2016
43. F2‐01‐01: Oligodendrocyte‐Enriched Gene Networks Reveal Novel Pathways and Key Targets in the Pathogenesis of Alzheimer’s Disease
- Author
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Igor Katsyv, Eric E. Schadt, Joshua D. Aaker, Patrizia Casaccia, Brian Popko, Bin Zhang, Minghui Wang, Klaus-Armin Nave, Xianxiao Zhou, Jun Zhu, Won-Min Song, Kelly Del Tredici, and Andrew M. McKenzie
- Subjects
Epidemiology ,Health Policy ,05 social sciences ,Gene regulatory network ,Disease ,Oligodendrocyte ,Pathogenesis ,Psychiatry and Mental health ,Cellular and Molecular Neuroscience ,medicine.anatomical_structure ,Developmental Neuroscience ,050501 criminology ,Key (cryptography) ,medicine ,0501 psychology and cognitive sciences ,Neurology (clinical) ,Geriatrics and Gerontology ,Psychology ,Neuroscience ,050104 developmental & child psychology ,0505 law - Published
- 2016
44. S4‐02‐03: Accelerating Medicines Partnership: Co‐Expression Networks
- Author
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Patrizia Casaccia, Andrew M. McKenzie, Pavel Katsel, Bin Zhang, Panos Roussos, Vahram Haroutunian, Eric E. Schadt, and Minghui Wang
- Subjects
Psychiatry and Mental health ,Cellular and Molecular Neuroscience ,Developmental Neuroscience ,Expression (architecture) ,Epidemiology ,Health Policy ,General partnership ,Neurology (clinical) ,Business ,Geriatrics and Gerontology ,Cell biology - Published
- 2016
45. O2‐10‐06: A Common Allele in SPI1 Lowers Risk and Delays Age at Onset for Alzheimer's Disease
- Author
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Julie Williams, Jonathan L. Haines, Philippe Amouyel, Oscar Harari, Ingrid B. Borecki, John S. K. Kauwe, Laura Ibanez, Gerard D. Schellenberg, Kuan-lin Huang, Manav Kapoor, John P. Budde, Richard Mayeux, Yuetiva Deming, Jean-Charles Lambert, Denise Harold, Alan E. Renton, Sheng Chih Jin, Benjamin Grenier-Boley, Jorge L. Del-Aguila, Céline Bellenguez, Eduardo Marcora, Sarah Bertelsen, Alison Goate, Paul Hollingworth, Carlos Cruchaga, Vincent Chouraki, Lindsay A. Farrer, Andrew M. McKenzie, Bin Zhang, Jake Czajkowski, Sudha Seshadri, Maria Victoria Fernandez, and Margaret A. Pericak-Vance
- Subjects
Epidemiology ,business.industry ,Health Policy ,Disease ,03 medical and health sciences ,Psychiatry and Mental health ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,Developmental Neuroscience ,Immunology ,Medicine ,030212 general & internal medicine ,Neurology (clinical) ,Geriatrics and Gerontology ,Allele ,business ,030217 neurology & neurosurgery - Published
- 2016
46. The human-specific CASP4 gene product contributes to Alzheimer-related synaptic and behavioural deficits
- Author
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Gregory A. Elder, Dara L. Dickstein, Miguel A. Gama Sosa, Bin Zhang, Andrew M. McKenzie, James Schmeidler, Nate P. Dorr, Yuji Kajiwara, Joseph D. Buxbaum, and Ozlem Bozdagi
- Subjects
0301 basic medicine ,Amyloid beta ,Hippocampus ,Mice, Transgenic ,Plaque, Amyloid ,Presenilin ,03 medical and health sciences ,Amyloid beta-Protein Precursor ,Mice ,Immune system ,Alzheimer Disease ,Genetics ,PSEN1 ,medicine ,Presenilin-1 ,Animals ,Humans ,Cognitive Dysfunction ,Molecular Biology ,Genetics (clinical) ,Innate immune system ,Neuronal Plasticity ,biology ,General Medicine ,Articles ,medicine.disease ,Caspases, Initiator ,Barnes maze ,Disease Models, Animal ,030104 developmental biology ,Gene Expression Regulation ,biology.protein ,Microglia ,Alzheimer's disease ,Neuroscience - Abstract
Recent studies have indicated that innate immune signalling molecules are involved in late-onset Alzheimer's disease (LOAD) risk. Amyloid beta (Aβ) accumulates in AD brain, and has been proposed to act as a trigger of innate immune responses. Caspase-4 is an important part of the innate immune response. We recently characterized transgenic mice carrying human CASP4, and observed that the mice manifested profound innate immune responses to lipopolysaccharide (LPS). Since these inflammatory processes are important in the aetiology of AD, we have now analysed the correlation of expression of caspase-4 in human brain with AD risk genes, and studied caspase-4 effects on AD-related phenotypes in APPswe/PS1deltaE9 (APP/PS1) mice. We observed that the expression of caspase-4 was strongly correlated with AD risk genes including TYROBP, TREM2, CR1, PSEN1, MS4A4A and MS4A6A in LOAD brains. Caspase-4 expression was upregulated in CASP4/APP/PS1 mice in a region-specific manner, including hippocampus and prefrontal cortex. In APP/PS1 mice, caspase-4 expression led to impairments in the reversal phase of a Barnes maze task and in hippocampal synaptic plasticity, without affecting soluble or aggregated Aβ levels. Caspase-4 was expressed predominantly in microglial cells, and in the presence of CASP4, more microglia were clustered around amyloid plaques. Furthermore, our data indicated that caspase-4 modulates microglial cells in a manner that increases proinflammatory processes. We propose that microglial caspase-4 expression contributes to the cognitive impairments in AD, and that further study of caspase-4 will enhance our understanding of AD pathogenesis and may lead to novel therapeutic targets in AD.
- Published
- 2016
47. Tumor therapy with a urokinase plasminogen activator-activated anthrax lethal toxin alone and in combination with paclitaxel
- Author
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Stephen H. Leppla, Andrew M. McKenzie, Yi Zhang, Shihui Liu, and Alexander N. Wein
- Subjects
Skin Neoplasms ,Paclitaxel ,Cell Survival ,Anthrax toxin ,Bacterial Toxins ,Melanoma, Experimental ,Pharmacology ,Biology ,Article ,Mice ,chemistry.chemical_compound ,Stroma ,In vivo ,Cell Line, Tumor ,medicine ,Animals ,Humans ,Pharmacology (medical) ,Urokinase ,Antigens, Bacterial ,Sunitinib ,Antineoplastic Agents, Phytogenic ,Urokinase-Type Plasminogen Activator ,In vitro ,Tumor Burden ,Mice, Inbred C57BL ,Oncology ,chemistry ,Tumor progression ,medicine.drug - Abstract
PA-U2, an engineered anthrax protective antigen that is activated by urokinase was combined with wild-type lethal factor in the treatment of Colo205 colon adenocarcinoma in vitro and B16-BL6 mouse melanoma in vitro and in vivo. This therapy was also tested in combination with the small molecule paclitaxel, based on prior reports suggesting synergy between ERK1/2 inhibition and chemotherapeutics. Colo205 was sensitive to PA-U2/LF while B16-BL6 was not. For the combination treatment of B16-BL6, paclitaxel showed a dose response in vitro, but cells remained resistant to PA-U2/LF even in the presence of paclitaxel. In vivo, each therapy slowed tumor progression, and an additive effect between the two was observed. Since LF targets tumor vasculature while paclitaxel is an anti-mitotic, it is possible the agents were acting against different cells in the stroma, precluding a synergistic effect. The engineered anthrax toxin PA-U2/LF warrants further development and testing, possibly in combination with an anti-angiogenesis therapy such as sunitinib or sorafinib.
- Published
- 2012
48. The dynamic relationships between world and domestic prices of rice under the regime of agricultural trade liberalization in Bangladesh
- Author
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Mohammad Jahangir Alam, Eric J. Wailes, Ismat Ara Begum, Guido Van Huylenbroeck, Jeroen Buysse, and Andrew M. McKenzie
- Subjects
Market integration ,Food security ,Cointegration ,business.industry ,Geography, Planning and Development ,International economics ,Development ,Domestic market ,Error correction model ,Agriculture ,Political Science and International Relations ,Economics ,Volatility (finance) ,business ,Free trade - Abstract
The article examines the dynamic relationship between the world and the domestic market price of rice for Bangladesh given agricultural trade liberalization. A Johansen multivariate cointegration test was used, followed by an error correction model. Results show that there exists a long-run unidirectional equilibrium relationship, meaning that the domestic prices adjust to the world prices but not vice versa. Our results highlight the dependence of the Bangladeshi rice market on the world rice market and underline the need for adequate policies which specifically address the issue of food security when world prices are very high. The goal of such policies should be to dampen or reduce domestic price volatility induced by the world market.
- Published
- 2012
49. How Much is That Exam Grade Really Worth? An Estimation of Student Risk Aversion to Their Unknown Final College Course Grades
- Author
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Lanier Nalley and Andrew M. McKenzie
- Subjects
Estimation ,Economics and Econometrics ,Actuarial science ,education ,Economics education ,Risk behavior ,Risk aversion (psychology) ,Laboratory experiment ,Psychology ,Expected utility hypothesis ,Education - Abstract
This study created an experimental design with which students can empirically assess their risk behavior with respect to exam grades within an expected utility framework. Specifically, the authors analyzed students’ risk preferences associated with taking exams and earning a “risky” unknown grade versus not taking exams and instead obtaining a “sure” grade. Students have grade-choice decisions in nonhypothetical situations that impact their actual exam grades. Estimates indicate that the more risk-averse a student is, the more willing he or she is to accept a lower certain grade and not take an exam than to run the risk of actually taking it. We believe that this experimental setup and its binding results make it an easy but effective way of teaching the obtuse concept of risk aversion.
- Published
- 2011
50. Is there co-movement of agricultural commodities futures prices and crude oil?
- Author
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Mohammad Jahangir Alam, Andrew M. McKenzie, Guido Van Huylenbroeck, and Valeri Natanelov
- Subjects
Consumption (economics) ,General Energy ,Cointegration ,Biofuel ,Financial economics ,Financial market ,Commodity ,Economics ,Monetary economics ,Oil-storage trade ,Management, Monitoring, Policy and Law ,Futures contract ,Energy policy - Abstract
Even though significant attempts have appeared in literature, the current perception of co-movement of commodity prices appear inadequate and static. In particular we focus on price movements between crude oil futures and a series of agricultural commodities and gold futures. A comparative framework is applied to identify changes in relationships through time and various cointegration methodologies and causality tests are employed. Our results indicate that co-movement is a dynamic concept and that some economic and policy development may change the relationship between commodities. Furthermore we show that biofuel policy buffers the co-movement of crude oil and corn futures until the crude oil prices surpass a certain threshold.
- Published
- 2011
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