15 results on '"cyclical"'
Search Results
2. Myron Gordon Award Lecture 2023: Painting the neural crest: How studying pigment cells illuminates neural crest cell biology.
- Author
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Kelsh, Robert N.
- Subjects
- *
NEURAL crest , *CHROMATOPHORES , *CYTOLOGY , *CELL aggregation , *BIOLOGICAL models - Abstract
It has been 30 (!!) years since I began working on zebrafish pigment cells, as a postdoc in the laboratory of Prof. Christiane Nüsslein‐Volhard. There, I participated in the first large‐scale mutagenesis screen in zebrafish, focusing on pigment cell mutant phenotypes. The isolation of colourless, shady, parade and choker mutants allowed us (as a postdoc in Prof. Judith Eisen's laboratory, and then in my own laboratory at the University of Bath since 1997) to pursue my ambition to address long‐standing problems in the neural crest field. Thus, we have studied how neural crest cells choose individual fates, resulting in our recent proposal of a new, and potentially unifying, model which we call Cyclical Fate Restriction, as well as addressing how pigment cell patterns are generated. A key feature of our work in the last 10 years has been the use of mathematical modelling approaches to clarify our biological models and to refine our interpretations. None of this would have been possible without a hugely talented group of laboratory members and other collaborators from around the world—it has been, and I am sure will continue to be, a pleasure and privilege to work with you all! [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Analysis of GDP of the United States (1981-2021)
- Author
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Kuang, Jincheng, Appolloni, Andrea, Series Editor, Caracciolo, Francesco, Series Editor, Ding, Zhuoqi, Series Editor, Gogas, Periklis, Series Editor, Huang, Gordon, Series Editor, Nartea, Gilbert, Series Editor, Ngo, Thanh, Series Editor, Striełkowski, Wadim, Series Editor, Cao, Feng-xia, editor, Singh, Satya Narayan, editor, Jusoh, Ahmad, editor, and Mishra, Deepanjali, editor
- Published
- 2024
- Full Text
- View/download PDF
4. Historical perspectives on time and temporality.
- Author
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Baker, Charles Richard
- Abstract
Copyright of Recherches en Sciences de Gestion is the property of ISEOR and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
5. U.S. GDP Detrended Analysis
- Author
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Hu, Pan, Ji, Peiyao, Xu, Huishan, Shi, Xingyu, Wu, Yi, Appolloni, Andrea, Series Editor, Caracciolo, Francesco, Series Editor, Ding, Zhuoqi, Series Editor, Gogas, Periklis, Series Editor, Huang, Gordon, Series Editor, Nartea, Gilbert, Series Editor, Ngo, Thanh, Series Editor, Striełkowski, Wadim, Series Editor, Kadry, Seifedine, editor, Yan, Yingchen, editor, and Xia, Junjie, editor
- Published
- 2023
- Full Text
- View/download PDF
6. 中国牛肉价格波动特征及其影响因素分析.
- Author
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森巴提窑叶尔兰, 袁 朱增勇, and 袁 杨春
- Subjects
PRICE regulation ,PRICE fluctuations ,PRICES ,BEEF industry ,MARKET prices - Abstract
Copyright of Agricultural Outlook (1673-3908) is the property of Institute of Agricultural Information, Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2023
7. Empirical assessment of alternative methods for identifying seasonality in observational healthcare data
- Author
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Anthony Molinaro and Frank DeFalco
- Subjects
ACHILLES ,ARIMA ,CASTOR ,Classification ,Common data model ,Cyclical ,Medicine (General) ,R5-920 - Abstract
Abstract Background Seasonality classification is a well-known and important part of time series analysis. Understanding the seasonality of a biological event can contribute to an improved understanding of its causes and help guide appropriate responses. Observational data, however, are not comprised of biological events, but timestamped diagnosis codes the combination of which (along with additional requirements) are used as proxies for biological events. As there exist different methods for determining the seasonality of a time series, it is necessary to know if these methods exhibit concordance. In this study we seek to determine the concordance of these methods by applying them to time series derived from diagnosis codes in observational data residing in databases that vary in size, type, and provenance. Methods We compared 8 methods for determining the seasonality of a time series at three levels of significance (0.01, 0.05, and 0.1), against 10 observational health databases. We evaluated 61,467 time series at each level of significance, totaling 184,401 evaluations. Results Across all databases and levels of significance, concordance ranged from 20.2 to 40.2%. Across all databases and levels of significance, the proportion of time series classified seasonal ranged from 4.9 to 88.3%. For each database and level of significance, we computed the difference between the maximum and minimum proportion of time series classified seasonal by all methods. The median within-database difference was 54.8, 34.7, and 39.8%, for p
- Published
- 2022
- Full Text
- View/download PDF
8. Empirical assessment of alternative methods for identifying seasonality in observational healthcare data.
- Author
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Molinaro, Anthony and DeFalco, Frank
- Subjects
- *
TIME series analysis - Abstract
Background: Seasonality classification is a well-known and important part of time series analysis. Understanding the seasonality of a biological event can contribute to an improved understanding of its causes and help guide appropriate responses. Observational data, however, are not comprised of biological events, but timestamped diagnosis codes the combination of which (along with additional requirements) are used as proxies for biological events. As there exist different methods for determining the seasonality of a time series, it is necessary to know if these methods exhibit concordance. In this study we seek to determine the concordance of these methods by applying them to time series derived from diagnosis codes in observational data residing in databases that vary in size, type, and provenance.Methods: We compared 8 methods for determining the seasonality of a time series at three levels of significance (0.01, 0.05, and 0.1), against 10 observational health databases. We evaluated 61,467 time series at each level of significance, totaling 184,401 evaluations.Results: Across all databases and levels of significance, concordance ranged from 20.2 to 40.2%. Across all databases and levels of significance, the proportion of time series classified seasonal ranged from 4.9 to 88.3%. For each database and level of significance, we computed the difference between the maximum and minimum proportion of time series classified seasonal by all methods. The median within-database difference was 54.8, 34.7, and 39.8%, for p < 0.01, 0.05, and 0.1, respectively.Conclusion: Methods of binary seasonality classification when applied to time series derived from diagnosis codes in observational health data produce inconsistent results. The methods exhibit considerable discord within all databases, implying that the discord is a result of the difference between the methods themselves and not due to the choice of database. The results indicate that researchers relying on automated methods to assess the seasonality of time series derived from diagnosis codes in observational data should be aware that the methods are not interchangeable and thus the choice of method can affect the generalizability of their work. Seasonality determination is highly dependent on the method chosen. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
9. Global Climate Change -- What is Happening and What to Expect.
- Author
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Maslov, Lev A.
- Subjects
CLIMATE change ,MILANKOVITCH cycles ,DROUGHTS ,GLOBAL warming ,ATMOSPHERE ,SOLAR activity ,GLACIATION - Abstract
Different mechanisms of glacial-interglacial cycles and of the current global warming are considered and discussed: Milankovitch astronomical cycles, self-organization processes in Earth's geospheres, variation of Solar activity, increased concentration of greenhouse gases. It is pointed out that the current global warming cycle has started, according to data presented in J.R. Petit, at al., (1999, 2001), thousands of years before the first machines, even very primitive, were made by people. It is pointed out also that release of CH4 gas into atmosphere is an irreversible, uncontrolled process triggered by global warming. It is hypothesized that the planetary overheated atmosphere is in a state similar to "boiling". This explains the increased number and severity of different natural catastrophes -- hurricanes, floods, droughts. It is also shown that in each cycle the cooling down of atmosphere follows the Newton's Law of cooling suggesting a clear conceptual view of the Physics of this process. Finally, a mechanism explaining sharp the rise of temperature of atmosphere at the end of each glacial period is suggested and evaluated. [ABSTRACT FROM AUTHOR]
- Published
- 2022
10. Forecasting Traffic Accidents in Developing Countries Using Time Series Analysis.
- Author
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Khasawneh, Mohammad Ali, Al-Omari, Aslam Ali, and Ganam, Bader
- Subjects
- *
TIME series analysis , *TRAFFIC estimation , *TIME management , *TRAFFIC safety , *TRAFFIC accidents , *SAFETY ,DEVELOPING countries - Abstract
The main objective of this study is to develop models that can forecast traffic accidents, injuries and fatalities in developing countries. Consequently, this could set the first step in enhancing traffic safety measures as well as to help planning for the future. Moreover, results of this investigation may assist decision and law makers at transportation and traffic agencies to come up with resolutions for the increasing traffic crashes and consequently loss of lives, properties and the high cost involved. The forecasting models were developed using the well-known time series analysis. Each time series model was decomposed into its components (trend, cyclical, seasonal and irregular components). In conclusion, the forecasting by time series analysis explained a significant proportion of the variability in the dependent variables (accidents, injuries and fatalities) as shown by the relatively acceptable coefficients of determination (R²). [ABSTRACT FROM AUTHOR]
- Published
- 2022
11. Drift-Free 3D Orientation and Displacement Estimation for Quasi-Cyclical Movements Using One Inertial Measurement Unit: Application to Running
- Author
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Marit A. Zandbergen, Jasper Reenalda, Robbert P. van Middelaar, Romano I. Ferla, Jaap H. Buurke, and Peter H. Veltink
- Subjects
inertial measurement unit ,drift-free ,orientation ,displacement ,cyclical ,running ,Chemical technology ,TP1-1185 - Abstract
A Drift-Free 3D Orientation and Displacement estimation method (DFOD) based on a single inertial measurement unit (IMU) is proposed and validated. Typically, body segment orientation and displacement methods rely on a constant- or zero-velocity point to correct for drift. Therefore, they are not easily applicable to more proximal segments than the foot. DFOD uses an alternative single sensor drift reduction strategy based on the quasi-cyclical nature of many human movements. DFOD assumes that the quasi-cyclical movement occurs in a quasi-2D plane and with an approximately constant cycle average velocity. DFOD is independent of a constant- or zero-velocity point, a biomechanical model, Kalman filtering or a magnetometer. DFOD reduces orientation drift by assuming a cyclical movement, and by defining a functional coordinate system with two functional axes. These axes are based on the mean acceleration and rotation axes over multiple complete gait cycles. Using this drift-free orientation estimate, the displacement of the sensor is computed by again assuming a cyclical movement. Drift in displacement is reduced by subtracting the mean value over five gait cycle from the free acceleration, velocity, and displacement. Estimated 3D sensor orientation and displacement for an IMU on the lower leg were validated with an optical motion capture system (OMCS) in four runners during constant velocity treadmill running. Root mean square errors for sensor orientation differences between DFOD and OMCS were 3.1 ± 0.4° (sagittal plane), 5.3 ± 1.1° (frontal plane), and 5.0 ± 2.1° (transversal plane). Sensor displacement differences had a root mean square error of 1.6 ± 0.2 cm (forward axis), 1.7 ± 0.6 cm (mediolateral axis), and 1.6 ± 0.2 cm (vertical axis). Hence, DFOD is a promising 3D drift-free orientation and displacement estimation method based on a single IMU in quasi-cyclical movements with many advantages over current methods.
- Published
- 2022
- Full Text
- View/download PDF
12. La demanda d'habitatge. Quo vadis?
- Author
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Módenes Cabrerizo, Juan Antonio
- Subjects
Demanda demogràfica cíclica ,Catalonia ,Mercado de la vivienda ,Mercat de l'habitatge ,Inmigración ,Catalunya ,Cyclical ,Immigration ,Housing market ,Polítiques d'habitatge ,Housing policies ,Demographic demand ,Immigració ,Políticas de vivienda - Abstract
This work has been funded by the project PID2020-113665RB-I00, Ministry of Science and Innovation (Spain). My thanks to Tere Menacho (CED) for her great help in data handling. Un dels temes més importants de debat polític i social a Catalunya i Espanya dels últims anys ha estat el mal funcionament del mercat de l'habitatge. A partir del cas de Catalunya, proposem diverses explicacions d'origen demogràfic per a aquest fet. Primer, hi ha un problema creixent de desajust entre la demanda demogràfica d'habitatges i la nova oferta disponible. Segons les nostres estimacions, en el període expansiu 2014-2020 l'estoc de llars catalanes es va incrementar en 222.000 unitats fins als 3,1 milions, mentre que només es van finalitzar 50.000 habitatges. El 2019, el dèficit de nou habitatge, mesurat com la diferència entre saldo net de llars i habitatges finalitzats, va ser de 35 mil. Segon, la demanda demogràfica ja no és estable sinó cíclica i incerta. El 2013 es van afegir unes 9 mil llars a l'estoc, el 2019 45 mil. Disparitats similars estan succeint al conjunt d'Espanya. En aquest Perspectives Demogràfiques, mostrem com ha canviat la distribució dels components demogràfics de la demanda cap a un pes més gran dels factors menys estables com ara la immigració, que va explicar el 93% del creixement net de llars el 2019, i l'evolució de l'estructura de les llars, que explicava més de 10 mil llars addicionals anuals en els primers anys 2000. A continuació, analitzem l'existència d'una desconnexió entre l'oferta i la demanda d'habitatges. Per últim, suggerim que un dels principals desafiaments de la demografia aplicada és ser útil per al disseny de noves polítiques d'habitatge, que tinguin en compte l'impacte cíclic de les conjuntures, la no-linealitat de les tendències i la incertesa. Uno de los mayores temas de debate político y social en Cataluña y España de los últimos años ha sido el mal funcionamiento del mercado de la vivienda. A partir del caso de Cataluña, proponemos varias explicaciones de origen demográfico para esta cuestión. Primero, existe un problema creciente de desajuste entre la demanda demográfica de viviendas y la nueva oferta disponible. Según nuestras estimaciones, en el periodo expansivo 2014-2020 el stock de hogares catalanes se incrementó en 222 mil unidades hasta los 3,1 millones, mientras que solo se finalizaron 50 mil viviendas. En 2019, el déficit de nueva vivienda, medido como la diferencia entre saldo neto de hogares y viviendas finalizadas, fue de 35 mil. Segundo, la demanda demográfica ya no es estable sino cíclica e incierta. En 2013 se añadieron unos 9 mil hogares al stock, en 2019 45 mil. Desajustes similares están sucediendo en el conjunto de España. En este Perspectives Demogràfiques, mostramos cómo ha cambiado la distribución de los componentes demográficos de la demanda hacia un mayor peso de los factores menos estables como la inmigración, que explicó el 93% del crecimiento neto de hogares en 2019, y la evolución de la estructura de los hogares, que explicaba más de 10 mil hogares adicionales anuales en los primeros años 2000. A continuación, analizamos la existencia de una desconexión entre la oferta y la demanda de viviendas. Por último, sugerimos que uno de los principales desafíos de la demografía aplicada es ser útil para el diseño de nuevas políticas de vivienda, que tengan en cuenta el impacto cíclico de las coyunturas, la no linealidad de las tendencias y la incertidumbre. One of the major issues of political and social discussion in Catalonia and Spain in recent years has been the malfunctioning of the housing market. Using the case of Catalonia, I suggest that there are several explanations of demographic origin for this. First, there is a growing mismatch between the demographic demand for housing and the new supply available. I estimate that in the period 2014-2020 the Catalan household stock increased by 222 thousand units to 3.1 million, while only 50 thousand dwellings were completed. In 2019, the deficit of new housing, measured as the difference between net household growth and completed dwellings, was 35 thousand. Second, demographic demand is no longer stable but cyclical and uncertain. In 2013 some 9 thousand households were added to the stock and, in 2019, 45 thousand. Similar mismatches are happening in Spain as a whole. In this issue of Perspectives Demogràfiques, I show how the distribution of the demographic components of demand has changed, tending to a greater weight of less stable factors like immigration, which accounted for 93% of net household growth in 2019, or the evolution of household structure, which explained more than 10 thousand additional households per year in the early 2000s. Next, I draw attention to the growing housing supply-demand mismatch. Finally, I suggest that one of the main challenges of applied demography is how to contribute towards new housing policies that consider the cyclical impact of conjunctures, non-linearity of trends, and uncertainty.
- Published
- 2023
13. Clinicopathological profile of mastalgia in females: incidence, types, and pathological correlations. a cross-Sectional study.
- Author
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Ali AA and Faraj FH
- Abstract
Introduction: Mastalgia was the most common symptom in patients attending a breast clinic. The two most common types of mastalgia were (cyclical and non-cyclical). The common cause of cyclical was Physiological changes due to premenstrual tension syndrome fibrocystic changes or fibroadenosis and (Aberrations in the Normal Development and Involution of the breast ). Non-cyclical diseases are mainly benign rather than malignant. Solid masses (fibroadenomas), cysts, infections, abscesses, trauma, and nipple discharge (hormones) are rare diseases associated with breast cancer. The aim of this study is to study the incidence of mastalgia, types (cyclical and non-cyclical) and pathological types of mastalgia (benign and malignant pathologies)., Material and Methods: A cross-sectional descriptive study of mastalgia was carried out at the Breast Center Department of Maternity Teaching Hospital located in Erbil, from January 2014 to September 2015. A total of 150 breast pain cases (available clinical data) were studied in detail., Results: There are two types of mastalgia based on triple assessments, these are as follows, cyclical 90 cases (60%) and non-cyclical 60 cases (40%). Fibrocystic breast changes or fibroadenosis 35 cases (23.3%) and thirdly nipple discharges as part of fibrocystic (fibroadenosis) five cases (3.3%). Non-cyclical mastalgia was subdivided into benign breast pathologies, fibroadenoma 30 cases (20%), breast cyst 10 cases (6.7%), nipple discharge (hormonal) five cases (3.3%), mastitis three cases (2%) abscess two cases (1.3%), fat necrosis one case (0.7%), and malignant breast pathologies, cancer three cases (2%). Clinicopathological correlations in the current study were highly significant ( P <0.005)., Conclusion: Not all discomfort or pain can be diagnosed as mastalgia; occasionally, chest wall, referral pain, and systemic causes can mimic mastalgia. These results highlight the importance of differentiating between cyclical and non-cyclical mastalgia using clinical assessment, sonography, mammography, and blood investigations. Most mastalgia cases are benign, with cyclical mastalgia primarily related to hormonal changes during the menstrual cycle., Competing Interests: The authors declare that they have no conflicts of interest.Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)
- Published
- 2023
- Full Text
- View/download PDF
14. Global climate change -- What is happening and what to expect
- Author
-
Maslov, Lev
- Subjects
climate change ,cyclical ,Catastrophes - Abstract
Different mechanisms of glacial-interglacial cycles and of the current global warming are considered and discussed: Milankovitch astronomical cycles, self-organization processes in Earth's geospheres, variation of Solar activity, increased concentration of greenhouse gases. It is pointed out that the current global warming cycle has started, according to data presented in J.R. Petit, at al., (1999, 2001), thousands of years before the first machines, even very primitive, were made by people. It is pointed out also that release of CH4 gas into atmosphere is an irreversible, uncontrolled process triggered by global warming. It is hypothesized that the planetary overheated atmosphere is in a state similar to "boiling". This explains the increased number and severity of different natural catastrophes -- hurricanes, floods, droughts. It is also shown that in each cycle the cooling down of atmosphere follows the Newton's Law of cooling suggesting a clear conceptual view of the Physics of this process. Finally, a mechanism explaining sharp the rise of temperature of atmosphere at the end of each glacial period is suggested and evaluated.
- Published
- 2022
15. Drift-Free 3D Orientation and Displacement Estimation for Quasi-Cyclical Movements Using One Inertial Measurement Unit: Application to Running.
- Author
-
Zandbergen, Marit A., Reenalda, Jasper, van Middelaar, Robbert P., Ferla, Romano I., Buurke, Jaap H., and Veltink, Peter H.
- Subjects
- *
UNITS of measurement , *STANDARD deviations , *RUNNING speed , *MOTION capture (Human mechanics) , *HUMAN mechanics , *PHYSIOLOGICAL effects of acceleration , *KALMAN filtering - Abstract
A Drift-Free 3D Orientation and Displacement estimation method (DFOD) based on a single inertial measurement unit (IMU) is proposed and validated. Typically, body segment orientation and displacement methods rely on a constant- or zero-velocity point to correct for drift. Therefore, they are not easily applicable to more proximal segments than the foot. DFOD uses an alternative single sensor drift reduction strategy based on the quasi-cyclical nature of many human movements. DFOD assumes that the quasi-cyclical movement occurs in a quasi-2D plane and with an approximately constant cycle average velocity. DFOD is independent of a constant- or zero-velocity point, a biomechanical model, Kalman filtering or a magnetometer. DFOD reduces orientation drift by assuming a cyclical movement, and by defining a functional coordinate system with two functional axes. These axes are based on the mean acceleration and rotation axes over multiple complete gait cycles. Using this drift-free orientation estimate, the displacement of the sensor is computed by again assuming a cyclical movement. Drift in displacement is reduced by subtracting the mean value over five gait cycle from the free acceleration, velocity, and displacement. Estimated 3D sensor orientation and displacement for an IMU on the lower leg were validated with an optical motion capture system (OMCS) in four runners during constant velocity treadmill running. Root mean square errors for sensor orientation differences between DFOD and OMCS were 3.1 ± 0.4° (sagittal plane), 5.3 ± 1.1° (frontal plane), and 5.0 ± 2.1° (transversal plane). Sensor displacement differences had a root mean square error of 1.6 ± 0.2 cm (forward axis), 1.7 ± 0.6 cm (mediolateral axis), and 1.6 ± 0.2 cm (vertical axis). Hence, DFOD is a promising 3D drift-free orientation and displacement estimation method based on a single IMU in quasi-cyclical movements with many advantages over current methods. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
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