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The main objectives of this paper are to (a) explain the extent of vertical and horizontal intra-industry trade in the United State's foreign trade with the North American Free Trade Area (NAFTA), and (b) identify the industry-specific determinants of vertical and horizontal intra-industry trade. One of the main findings is that the observed increase in intra-industry trade between the United States and NAFTA is almost entirely due to two-way trade in vertical differentiation. Another important finding is that the share of horizontal intra-industry trade has increased significantly during this period, although vertical intra-industry trade continued to be dominant in the U.S.-NAFTA IIT Trade. Among the industry-specific variables, product differentiation, vertical product differentiation, and product quality differences are found to have a positive effect on all three types of IIT shares. Industry concentration and industry size are found to have a negative and statistically significant effect on all three types of IIT share. [ABSTRACT FROM AUTHOR]

The paper is a conclusion of an earlier study investigating contrasting views on Africa's development strategies. In this concluding part, we disaggregated the regional model and investigated same problem at the country level. Current country-level investigation is based on data evidence from Nigeria. Generally, results of current country-level study portray characteristics and tendencies similar to those observed at regional level. The investigation leads us to conclude that while African countries may well approach both international aid and external trade as complementary development vehicles, they would be much better off mounting endeavor to strengthen their trading position with the rest of the world. In other words, a much better policy approach to development is for them to view international aid as no more than a supplementary development tool. The results portray that while trade strengthens a country's bargaining position with the rest of the world, dependence on external aid tend to do the exact opposite. Countries that depend on external aid-in view of growth-stifling complexities-portray an observable tendency of economic stagnancy or slow growth. [ABSTRACT FROM AUTHOR]

A conducting polymer [polypyrrole (PPy)]-based amperometric biosensor fabricated on a platinum-coated nanoporous alumina electrode has been described. This fabricating process introduced artificial porosity into the PPy film, and the template pore sizes were carefully chosen to match the size of the glucose oxidase (GOx) molecule. The PF6--doped PPy film was synthesized with 0.05 M pyrrole and 0.1 M NaPF6 at a current density of 0.3 mA/cm² for 90 s. Immobilization was done by physically adsorbing 5 µL of GOx on the nanoporous PPy film. Glutaraldehyde (0.1 wt.%, S µL) was used for cross-linking. The synthesized films were characterized by using an electrochemical technique and scanning electron microscopy (SEM). Amperometric responses were measured as a function of different concentrations of glucose at 0.4 V. Nanoporous electrodes lead to high enzyme loading, whereas the use of a cross-linking agent increased stability, sensitivity, reproducibility, repeatability, and shelf life. [ABSTRACT FROM AUTHOR]

In the current paper, we examine contrasting views in literature on Africa's development strategies. Unlike past studies, the current paper is an empirical investigation based on new facts and data compiled from the transformed environment of investigated problem. The results-viewed in context of new realities surrounding the problem: (1) the on-going realignment of international relationships among nations; (2) the increasing effectiveness of trade compared to the increasing "politicization" of aid; (3) and the growth-stifling eligibility requirements being demanded by international creditors and donors-lead us to conclude that while African countries may well approach both international aid and external trade as complementary, alternative development vehicles, they would be much better off mounting endeavor to strengthen their trading position with the rest of the world, while they view international aid as no more than a supplementary development tool. [ABSTRACT FROM AUTHOR]

This paper examines the relationship between export growth and economic growth. We use cointegration and error-correction models to analyze the causal relationship between export growth and economic growth using a regional annual dataset of twelve Latin American and Caribbean countries from 1960 to 2002. This paper builds on existing literature that suggests export growth contribute positively to economic growth, therefore, providing some evidence supporting the export-led growth hypothesis. The empirical results indicate causal relationship flows from growth in exports to the growth in GDP for ten of the twelve countries studied. Furthermore, our research finds one-way Granger causality running from GDP to export growth for ten of the twelve countries. [ABSTRACT FROM AUTHOR]

This paper investigates the long-run demand for money and short-run dynamics of the long-run money demand function for Sri Lanka during the post-1977 period. While M1 is cointegrated with real income, nominal interest rate, short-term foreign interest rate, and real effective exchange rate, M2 is not. This suggests that monetary authorities should emphasize the narrow definition of money for monetary control. The one year fixed deposits rate is cointegrated with M 1, indicating the opportunity cost of holding money. Although the inflation rate is not cointegrated with M1, it seems to be an important determinant of the demand for M1 in the short-run. Results also suggest that the short-term foreign interest rate and the exchange rate can have important implications for the effectiveness of monetary policy. Monetary authorities must consider the response of domestic money demand to these external factors when formulating future monetary policies. [ABSTRACT FROM AUTHOR]

The article discusses the results of a survey that was conducted in major tourist locations in Sri Lanka to examine the status of the country's tortoiseshell trade. It mentions a reduction in the killing of local sea turtles for scutes to be made into souvenirs. Proprietors of tourist ships in tourist cities such as Kandy and Tangalle were also questioned on topics such as knowledge of the punishment and penalties for selling or possessing tortoise shell products.

Agroforestry (AF), a traditional land management system in Pakistan that provides great potential both to boost agriculture and reduce wood shortages. Previous work has identified many complex factors of AF covering socio-economic, and environmental impacts. Comparatively few have addressed the perception of the impact of AF. This study investigates the farmer perception of ecological impact derived from AF and the factors that influence their perception. The questionnaire was completed by 200 farmers in Northern irrigated plain in Pakistan, and the resulting descriptive statistics and a probit regression analysis were used to analyze the data. The results show that majority of farmers were believed AF increases the greenery, understory regeneration, water retention, and soil fertility of the farmland. In addition, the analysis shows that farmers' perceptions of AF were positively correlated with the native trees selected for cultivation. However, farmers who practice agrosilvopastoral system had less knowledge and perception of the ecological benefits of AF. Moreover, the study found, even though farmers plant exotic species they perceived that it had a negative impact on the water level and soil fertility. On the other hand, lack of technical knowledge also affected their perceived status. Therefore, designing and implementing informal education programs that collaborate with AF farmers and officials is suggested. [ABSTRACT FROM AUTHOR]

Estimation of plant community composition, aboveground biomass and carbon stock is crucial for understanding forest ecology, strengthening environmental management, and developing effective tools and policies for forest restoration. This study was conducted in nine different forest reserves in Sri Lanka from 2012 to 2018 to examine the impact of community-based forest restoration (CBFR) on stand structural attributes, aboveground biomass, and carbon stock compared to state-managed forests. In total, 180 plots (90 plots in community-managed restoration blocks (CMRBs) and 90 plots assigned to state-managed restoration blocks (SMRBs)) were sampled at the study site. To conduct an inventory of standing trees, circular plots with a radius of 12.6 m (equivalent to an area of 500 square meters) were established. The Shannon diversity index, Allometric equations and Difference in Differences (DID) estimation were used to assess the data. Our study provides evidence of the positive impact of the CBFR program on enriching trees diversity. Considering stand structural attributes of both blocks showed higher trees density in the smaller diameter at breast height (DBH) category, indicating growth in both CMRBs and SMRBs. The results showed that tree biomass and carbon density were disproportionally distributed across the nine different forest reserves. On average, tree biomass and carbon density were higher in SMRBs (79.97 Mg ha -1 , 37.58 Mg C ha -1 ) compared to CMRBs (33.51 Mg ha -1 , 15.74 Mg C ha -1 ). However, CMRBs in Madigala reserve represent the highest biomass (56.53 and 59.92 Mg ha -1 ) and carbon density (26.57 and 28.16 Mg C ha -1 ). The results of biomass and carbon estimates were higher in all SMRBs in the nine different forest reserves compared to CMRBs. The findings suggest that future forest restoration programs in Sri Lanka should enhance participatory approaches to optimize tree species diversity, density and carbon storage, particularly in community-controlled forests. Our findings could assist developing tropical nations in understanding how CBFR impacts forest restoration objectives and improves the provision of ecological services within forests., Competing Interests: The authors declare that they have no competing interests., (© 2024 Ahmad et al.)

Models of populations in habitat networks are vital for understanding and linking processes and patterns across individuals, environments, ecological interactions, and population structures. River ecosystem models combine the physical structure of the networks with the biological processes of the organisms using structural and functional models, respectively. Previous studies on dendritic river networks have employed different functional (population) models and either directly claimed or implied that the results illustrate general properties of actual river systems. However, these studies have used different approaches and assumptions when modeling population characteristics and behavior, and it is possible that inferences regarding a system may vary based on the combination of functional model and the spatial structure of a network. This study aims to understand if different functional models in river systems produce substantially different model results and, therefore, whether conclusions are model-dependent. We compare variation in extinction time and occupancy proportion of river networks with linear, trellis, dendritic and ring-lattice topologies, using three population models (uniform, age-class and individual based) and one metapopulation-based (patch-occupancy) model. Dendritic, linear, and trellis structures did not show notable differences among extinction times for any of the four models. The difference between topologies was higher for the patch-occupancy model compared to the three population models. There were significant differences in the variations of patch-occupancy between the metapopulation and the population models, but the three population models of differing complexity produced broadly similar results. Therefore, if the occupancy data is obtained based on local subpopulations, spatial arrangement and connectivity does not appear to be the sole predictor of single-species metapopulation responses. We conclude that the outputs from functional models are robust to assumptions and varying levels of detail as long as they contain at least some detail at the level of individuals within habitat nodes. Also, if we are modeling network-scale populations, models that include at least some detailed information on individuals are a far better choice than considering populations implicitly., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Extensive use of herbicides is common among rural agricultural workers in Sri Lanka. Recent studies have postulated their role in the development of chronic kidney disease of unknown etiology (CKDu). Paraquat and glyphosate are leading herbicides used by sugarcane farmers (SF), hence occupational exposure is inevitable. This study examined the expression of urinary paraquat, glyphosate and biomarkers among residential SF in CKDu emerging regions, Warunagama (WA) and Rahathangama (RH), in the Uva Province with non-endemic Matara (MA) in the Southern Province of Sri Lanka. Urinary glyphosate, Paraquat, kidney injury molecule -1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL) and β2-microglobulin (B2M) were determined using enzyme-linked immunosorbent assays (ELISA). Urinary creatinine, microalbumin, serum creatinine (SCr), serum cystatin C, estimated glomerular filtration rate (eGFR), and albumin creatinine ratio (ACR) were also assessed. Generally, herbicide residues and kidney injury biomarkers were higher in SF compared to the non-endemic MA. Creatinine-adjusted urinary glyphosate and paraquat levels were significantly higher in WA compared to MA. ACR in RH (median 14.9; IQR 5.4-393.1 mg/g) and WA (23.7; 11.5-64.6) was significantly higher than MA (4.3; 2.2-6.7). This study reports 39 individuals with impaired kidney function among SF in Sri Lanka for the first time. Urinary NGAL levels were significantly higher in both WA (median 2.14; IQR 1.28-6.15 ng/mg Cr) and RH (3.09; 1.15-9.09) compared to MA (1.28; 0.56-2.81). However, urinary KIM-1 levels in RH (3.2; 1.29-106.1 ng/g Cr) and WA (3.6; 1.94-115.1) were not significantly higher in MA (1.74; 0.76-116.9). Urinary NGAL (r = 0.493), eGFR (r = -0.147) and ACR (r = 0.171) significantly correlated with urinary glyphosate, but not with urinary paraquat levels. Urinary KIM-1 levels did not correlate with either urinary glyphosate or paraquat, while urinary B2M and serum cystatin C levels showed significant correlation with urinary glyphosate levels. The current study reports higher urinary herbicide levels among sugarcane farmers in WA and RH, and that is potentially linked to the subsequent decline in kidney function, as indicated by ACR, eGFR, and NGAL. We posit that these indicators may serve as markers to detect renal injury among herbicide-exposed SF in Rural Sri Lanka.

Chronic kidney disease of unknown etiology (CKDu) is an emerging global concern affecting several agricultural communities in the Americas and South Asia. Environmental contaminants such as heavy metals (e.g., Cd, As, Pb, and V) and organic pesticides (e.g., glyphosate) in the drinking water have been hypothesized to play a role in childhood onset and progression of this disease. However, a comprehensive analysis of chemical contaminants in the drinking water and effects of these compounds and their mixtures on kidney development and function remains unknown. Here, we conducted targeted and non-targeted chemical analyses of sediment and drinking water in CKDu affected regions in Sri Lanka, one of the most affected countries. Using zebrafish Danio rerio, a toxicology and kidney disease model, we then examined kidney developmental effects of exposure to (i) environmentally derived samples from CKDu endemic and non-endemic regions and (ii) Cd, As, V, Pb, and glyphosate as individual compounds and in mixtures. We found that drinking water is contaminated with various organic chemicals including nephrotoxic compounds as well as heavy metals, but at levels considered safe for drinking. Histological studies and gene expression analyses examining markers of kidney development (pax2a) and kidney injury (kim1) showed novel metal and glyphosate-metal mixture specific effects on kidney development. Mitochondrial dysfunction is directly linked to kidney failure, and examination of mixture specific mitochondrial toxicity showed altered mitochondrial function following treatment with environmental samples from endemic regions. Collectively, we show that metals in drinking water, even at safe levels, can impede kidney development at an early age, potentiating increased susceptibility to other agrochemicals such as glyphosate. Drinking water contaminant effects on mitochondria can further contribute to progression of kidney dysfunction and our mitochondrial assay may help identify regions at risk of CKDu., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

A novel amperometric biosensor based on polypyrrole (PPy) nanotube array deposited on a Pt plated nano-porous alumina substrate and its performances are described. Glucose oxidase (GOx) enzyme was selected as the model enzyme in this study. Commercially available nano-porous alumina discs were used to fabricate electrodes in order to study the feasibility of enzyme entrapment by physical adsorption. A PPy/PF6- film comprising of nanotube array was synthesized using a solution containing 0.05 M Pyrrole and 0.1 M NaPF6 at a current density of 0.3 mA/cm2 for 90 s. The immobilization was done by physical adsorption of 5 microL of GOx (from a stock solution of 2 mg/mL of 210 U/mg) on each electrode. A sensitivity of 7.4 mA cm(-2) M(-1) was observed with PPy nanotube array where the maximum tube diameter was 100 nm. A linear range of 500 microM-13 mM and a response time of about 3 s were observed with a nanotube array where the maximum tube diameter was 200 nm. The synthesized nanotube arrays were characterized by galvanostatic electrochemical technique. Calculated value of apparent Michaelis-Menten constant (Km) was 7.01 mM. The use of nano-porous template electrodes leads to an efficient enzyme loading and provides an increased surface area for sensing the reaction. These factors contribute to increase the characteristic performances of the novel biosensor.

Twigs of Calophyllum cordato-oblongum have been shown to contain a new pyranocoumarin, the methyl ether of cordatolide B, three reported pyranocoumarins, cordato-oblongic acid, friedelin, canophyllol and taraxerol. Buds of this species contained large quantities of pyranocoumarins and a small amount of sitosterol. This observation indicates that the coumarin-synthesising tissues are mainly located at the non woody young plant parts of C. cordato-oblongum.

In a cross-sectional survey, we estimated the prevalence of coronary heart disease in a sample of 975 middle-aged males (35-59 years), from a defined population in the Central province of Sri Lanka using the London School of Hygiene cardiovascular questionnaire and a 12-lead electrocardiogram. The estimated prevalence rates were: (a) Definitive evidence of ischemic heart disease (positive symptoms and ECG changes of ischemia), 16/1000 (95% C.L., 9-27). (b) Evidence of coronary heart disease based on history alone 54/1000 (95% C.L., 40-71). (c) Estimate based on ECG changes of ischemia without symptoms 32/1000 (95% C.L., 21-46). Median values for major risk factors were: systolic blood pressure 120 mmHg, diastolic blood pressure 88 mmHg, serum cholesterol 4.99 mmol/l, high density lipoproteins 0.99 mmol/l and body-mass index 20.4 kg/m2. About half (57.9%) the subjects were current smokers, 17% had actual hypertension (systolic blood pressure > 159 mmHg and/or diastolic blood pressure > 94 mmHg and/or been treated for hypertension), 12.6% had hypercholesterolemia (serum cholesterol levels > 6.5 mmol/l), 18.4% had a body-mass index > 24 kg/m2 and 5.8% were diabetic. Hypercholesterolemia (> 6.5 mmol/l), a higher body-mass index (> 24 kg/m2) and diabetes were more prevalent among subjects living in an urban rather than a rural environment.