WorldWideScience

Sample records for epidemiological transition hypothesis

  1. Evaluating the Liquid Liquid Phase Transition Hypothesis of Supercoooled Water

    Science.gov (United States)

    Limmer, David; Chandler, David

    2011-03-01

    To explain the anomalous behavior of supercooled water it has been conjectured that buried within an experimentally inaccessible region of liquid water's phase diagram there exists a second critical point, which is the terminus of a first order transition line between two distinct liquid phases. The so-called liquid-liquid phase transition (LLPT) has since generated much study, though to date there is no consensus on its existence. In this talk, we will discuss our efforts to systematically study the metastable phase diagram of supercooled water through computer simulation. By employing importance-sampling techniques, we have calculated free energies as a function of the density and long-range order to determine unambiguously if two distinct liquid phases exist. We will argue that, contrary to the LLPT hypothesis, the observed phenomenology can be understood as a consequence of the limit of stability of the liquid far away from coexistence. Our results suggest that homogeneous nucleation is the cause of the increased fluctuations present upon supercooling. Further we will show how this understanding can be extended to explain experimental observations of hysteresis in confined supercooled water systems.

  2. Climate change, human health, and epidemiological transition.

    Science.gov (United States)

    Barrett, Bruce; Charles, Joel W; Temte, Jonathan L

    2015-01-01

    The health of populations depends on the availability of clean air, water, food, and sanitation, exposure to pathogens, toxins and environmental hazards, and numerous genetic, behavioral and social factors. For many thousands of years, human life expectancy was low, and population growth was slow. The development of technology-based civilizations facilitated what Abdel Omran called "epidemiological transition," with increasing life expectancy and rapid population growth. To a large extent, the spectacular growth of human populations during the past two centuries was made possible by the energy extracted from fossil fuels. We have now learned, however, that greenhouse gases from fossil fuel combustion are warming the planet's surface, causing changes in oceanic and atmospheric systems, and disrupting weather and hydrological patterns. Climate change poses unprecedented threats to human health by impacts on food and water security, heat waves and droughts, violent storms, infectious disease, and rising sea levels. Whether or not humanity can reduce greenhouse gas emissions quickly enough to slow climate change to a rate that will allow societies to successfully adapt is not yet known. This essay reviews the current state of relevant knowledge, and points in a few directions that those interested in human health may wish to consider. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. The Epidemiological Transition: Policy and Planning Implications for ...

    African Journals Online (AJOL)

    Relevant literatures were reviewed from medical journals, library search and internet source using Google search engine as well as international, national and local journals. The key words employed were: Epidemiological Transition with particular emphasis on policy and planning implications in developing countries.

  4. [Epidemiological transition in Latin America: a comparison of four countries].

    Science.gov (United States)

    Albala, C; Vio, F; Yáñez, M

    1997-06-01

    In the last decade, Latin America has experienced important transformations in its health conditions, due to demographic changes and a rapid urbanization process. To analyze socioeconomic, demographic and epidemiological changes in Chile, Guatemala, Mexico and Uruguay and relate them to the different stages in the demographic and epidemiological transition of these countries. Data was obtained from official information of local and international organizations such as Pan-American Health Organization, United Nations, Latin American Center for Demography (CELADE) and World Bank. Guatemala is in a pre-transition stage with a high proportion of communicable diseases as causes of death (61%) as compared with Mexico (22%), Chile (13%) and Uruguay (7%). Mexico is in a prolonged transition situation and Chile is close to Uruguay in a post-transitional stage. Despite decreasing rates of mortality, the proportion of deaths represented by chronic diseases and injuries has increased to over 30% in all countries, except Uruguay. Adjusted mortality rates for cardiovascular diseases are lower in Latin American countries, as compared to Canada. However, excepting Guatemala, there are differences in the pattern of cardiovascular disease, with a higher mortality due to cerebrovascular and a lower mortality due to coronary artery diseases. An increment in non communicable diseases is expected for the next decades in Latin America. Analysis of demographic and epidemiological transition is crucial to define health policies and to adequate health systems to the new situations.

  5. Molecular biology, epidemiology, and the demise of the linear no-threshold hypothesis

    International Nuclear Information System (INIS)

    Pollycove, M.

    1998-01-01

    The LNT hypothesis is the basic principle of all radiation protection policy. This theory assumes that all radiation doses, even those close to zero, are harmful in linear proportion to dose and that all doses produce a proportionate number of harmful mutations, i.e., mis- or unrepaired DNA alterations. The LNT theory is used to generate collective dose calculations of the number of deaths produced by minute fractions of background radiation. Current molecular biology reveals an enormous amount of relentless metabolic oxidative free radical damage with mis/unrepaired alterations of DNA. The corresponding mis/unrepaired DNA alterations produced by background radiation are negligible. These DNA alterations are effectively disposed of by the DNA damage-control biosystem of antioxidant prevention, enzymatic repair, and mutation removal. High-dose radiation injures this biosystem with associated risk increments of mortality and cancer mortality. Low-dose radiation stimulates DNA damage-control with associated epidemiologic observations of risk decrements of mortality and cancer mortality, i.e., hormesis. How can this 40-year-old LNT paradigm continue to be the operative principle of radiation protection policy despite the contradictory scientific observations of both molecular biology and epidemiology and the lack of any supportive human data? The increase of public fear through repeated statements of deaths caused by 'deadly' radiation has engendered an enormous increase in expenditures now required to 'protect' the public from all applications of nuclear technology: medical, research, energy, disposal, and cleanup remediation. Government funds are allocated to appointed committees, the research they support, and to multiple environmental and regulatory agencies. The LNT theory and multibillion dollar radiation activities have now become a symbiotic self-sustaining powerful political and economic force. (author)

  6. Modeling the hepatitis A epidemiological transition in Brazil and Mexico.

    Science.gov (United States)

    Van Effelterre, Thierry; Guignard, Adrienne; Marano, Cinzia; Rojas, Rosalba; Jacobsen, Kathryn H

    2017-08-03

    Many low- to middle-income countries have completed or are in the process of transitioning from high or intermediate to low endemicity for hepatitis A virus (HAV). Because the risk of severe hepatitis A disease increases with age at infection, decreased incidence that leaves older children and adults susceptible to HAV infection may actually increase the population-level burden of disease from HAV. Mathematical models can be helpful for projecting future epidemiological profiles for HAV. An age-specific deterministic, dynamic compartmental transmission model with stratification by setting (rural versus urban) was calibrated with country-specific data on demography, urbanization, and seroprevalence of anti-HAV antibodies. HAV transmission was modeled as a function of setting-specific access to safe water. The model was then used to project various HAV-related epidemiological outcomes in Brazil and in Mexico from 1950 to 2050. The projected epidemiological outcomes were qualitatively similar in the 2 countries. The age at the midpoint of population immunity (AMPI) increased considerably and the mean age of symptomatic HAV cases shifted from childhood to early adulthood. The projected overall incidence rate of HAV infections decreased by about two thirds as safe water access improved. However, the incidence rate of symptomatic HAV infections remained roughly the same over the projection period. The incidence rates of HAV infections (all and symptomatic alone) were projected to become similar in rural and urban settings in the next decades. This model featuring population age structure, urbanization and access to safe water as key contributors to the epidemiological transition for HAV was previously validated with data from Thailand and fits equally well with data from Latin American countries. Assuming no introduction of a vaccination program over the projection period, both Brazil and Mexico were projected to experience a continued decrease in HAV incidence rates

  7. Turkey’s Epidemiological and Demographic Transitions: 1931-2013

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    Coşkun Bakar

    2017-08-01

    Full Text Available Background: The causes of death have changed with regard to the epidemiological and demographic events in society. There is no evidence of prior research into the epidemiological transition in Turkey. This transition in Turkey should be observed starting with the Ottoman Empire period (19th to early 20th century. However, information about the Ottoman Empire is quite limited. Aims: To discuss the epidemiological and demographic transitions in Turkey, using demographic, educational and urbanization data in our present study. Study Design: A descriptive archive study. Methods: Mortality statistics dating from 1931 and published by the Turkish Statistical Institute were analysed, and the causes of death were coded and classified according to ICD-10. Other data were obtained from the published reports and studies regarding the issue. Results: In the 1930s, Turkey’s life expectancy was low (aged 40 years, fertility and mortality rates were high (respectively 45% and 31%, and the main causes of death were infectious diseases. Nowadays, life expectancy is close to 80 years, the total fertility rate has dropped to 2.1 per woman, and the main causes of death are chronic diseases and cancer. The population rate in the urban areas has increased steadily from 24.2% in 1927 to 77.3% in 2012. level of education has also increased during this period. In 1935, less than 10% of women were literate, and in 2013 90% were literate. Qualitative and quantitative increase have been observed in the presentation and access of healthcare services compared to the early years of the Republic. Conclusion: Turkey has been undergoing a modernization period in the last 200 years, and it is believed that the epidemiological and demographic transitions result from this period. This process has led to urbanization and an increase in the level of education, as well as a decrease in premature deaths, lower fertility rates, and an increase in the elderly population and chronic

  8. Does the recent evolution of Canadian mortality agree with the epidemiologic transition theory?

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    Robert Choinière

    2008-06-01

    Full Text Available After studying the epidemiologic transition's situation in Canada, it is determined that the delimitation of temporal stages within the epidemiologic transition as put forward by Omran (1971, 1998, Olshansky and Ault (1986, Rogers and Hackenberg (1987 and Olshansky et al. (1998 does not suit the Canadian evolution. Many of the researchers' postulates on the epidemiologic transition were not confirmed, which leads us to assert that, since 1958, the epidemiologic transition is best described as an evolution process rather than specific stages confined within time limits.

  9. Transitional geomagnetic impulse hypothesis: Geomagnetic fact or rock-magnetic artifact?

    Science.gov (United States)

    Camps, Pierre; Coe, Robert S.; PréVot, Michel

    1999-08-01

    A striking feature of the Steens Mountain (Oregon) geomagnetic polarity reversal is the two (maybe three) extremely rapid field directional changes (6 degrees per day) proposed to account for unusual behavior in direction of remanent magnetization in a single lava flow. Each of these very fast field changes, or impulses, is associated with a large directional gap (some 90°) in the record. In order to check the spatial reproducibility of the paleomagnetic signal over distances up to several kilometers, we have carried out a paleomagnetic investigation of two new sections (B and F) in the Steens summit region which cover the second and the third directional gap. The main result is the description of two new directions, which are located between the pre second and post second impulse directions. These findings weigh against the hypothesis that the geomagnetic field cause the unusual intraflow fluctuations, which now appears to be more ad hoc as an explanation of the paleomagnetic data. However, the alternative baking hypothesis remains also ad hoc since we have to assume variable rock magnetic properties that we have not yet been able to detect within the flows at the original section Steens A and D 1.5 km to the north. In addition, new results for 22 transitional and normal lava flows in section B are presented that correlate well with earlier results from section A.

  10. Ethnography of epidemiologic transition: Avian flu, global health politics and agro-industrial capitalism in Thailand.

    Science.gov (United States)

    Chuengsatiansup, Komatra

    2008-04-01

    This paper situates the ethnography of avian flu within the geo-political context of a new epidemiologic transition. Drawing on anthropological experience and insight, this paper examines areas of enquiry in which an ethnographic approach could contribute to a better implementation of prevention and control measures. Within the context of newly emerging diseases and accelerated globalization, the task of ethnography needs to extend far beyond the local. This paper reveals two major global issues that the ethnography of epidemiologic transition must take into consideration: (1) Global agro-industrial capitalism, and (2) global politics in the context of international health organizations and multi-national drug companies. The case of Thailand poses a question of how the strength of ethnographic practice could be deployed to account for the reality of the global-local interface of the new epidemiologic transition.

  11. The Trade-Off between Female Fertility and Longevity during the Epidemiological Transition in the Netherlands

    DEFF Research Database (Denmark)

    Kaptijn, Ralf; Thomese, Fleur; Liefbroer, Aart C

    2015-01-01

    as an evolutionary trade-off between reproduction and survival. We examine the relationship between fertility and longevity during the epidemiological transition in the Netherlands. This period of rapid decline in mortality from infectious diseases offers a good opportunity to study the relationship between...... fertility and longevity, using registry data from 6,359 women born in The Netherlands between 1850 and 1910. We hypothesize that an initially negative relationship between women's fertility and their longevity gradually turns less negative during the epidemiological transition, because of decreasing costs...

  12. Determinants of epidemiologic transition in rural Africa: the role of socioeconomic status and drinking water source.

    Science.gov (United States)

    Engelaer, Frouke M; Koopman, Jacob J E; van Bodegom, David; Eriksson, Ulrika K; Westendorp, Rudi G J

    2014-06-01

    Many African countries experience a protracted epidemiologic transition, different from the classical transition in western societies. The factors driving this protracted transition are largely unknown. In northeast Ghana, we studied an ongoing epidemiologic transition and investigated the effects of socioeconomic status and drinking water source on the transition. During a 9-year period, we followed a cohort of almost 30 000 individuals and collected information on mortality and fertility rates. In addition, using the standards set out by the WHO, we obtained the causes of death by verbal autopsy. Individuals were stratified according to their socioeconomic status and the households' use of an improved or unimproved drinking water source. Mortality rates decreased by -5.0% annually (pwater source. Factors other than socioeconomic status and drinking water source are responsible for the observed declines in mortality and fertility observed during the protracted epidemiologic transition. Identifying the specific determinants of the ongoing transition is of importance, as they could be targeted in order to further improve public health in rural African countries. © The Author 2014. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. The obese gut microbiome across the epidemiologic transition

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    Lara R. Dugas

    2016-01-01

    Full Text Available Abstract The obesity epidemic has emerged over the past few decades and is thought to be a result of both genetic and environmental factors. A newly identified factor, the gut microbiota, which is a bacterial ecosystem residing within the gastrointestinal tract of humans, has now been implicated in the obesity epidemic. Importantly, this bacterial community is impacted by external environmental factors through a variety of undefined mechanisms. We focus this review on how the external environment may impact the gut microbiota by considering, the host’s geographic location ‘human geography’, and behavioral factors (diet and physical activity. Moreover, we explore the relationship between the gut microbiota and obesity with these external factors. And finally, we highlight here how an epidemiologic model can be utilized to elucidate causal relationships between the gut microbiota and external environment independently and collectively, and how this will help further define this important new factor in the obesity epidemic.

  14. Biomarkers in Czech workers exposed to 1,3-butadiene: a transitional epidemiologic study

    NARCIS (Netherlands)

    Albertini, Richard J.; Srám, Radim J.; Vacek, Pamela M.; Lynch, Jeremiah; Nicklas, Janice A.; van Sittert, Nico J.; Boogaard, Peter J.; Henderson, Rogene F.; Swenberg, James A.; Tates, Ad D.; Ward, Jonathan B.; Wright, Michael; Ammenheuser, Marinel M.; Binkova, Blanka; Blackwell, Walter; de Zwart, Franz A.; Krako, Dean; Krone, Jennifer; Megens, Hendricus; Musilová, Petra; Rajská, Gabriela; Ranasinghe, Asoka; Rosenblatt, Judah I.; Rössner, Pavel; Rubes, Jiri; Sullivan, Linda; Upton, Patricia; Zwinderman, Ailko H.

    2003-01-01

    A multiinstitutional, transitional epidemiologic study was conducted with a worker population in the Czech Republic to evaluate the utility of a continuum of non-disease biological responses as biomarkers of exposure to 1,3-butadiene (BD)* in an industrial setting. The study site included two BD

  15. The Global Epidemiologic Transition: Noncommunicable Diseases and Emerging Health Risk of Allergic Disease in Sub-Saharan Africa

    Science.gov (United States)

    Atiim, George A.; Elliott, Susan J.

    2016-01-01

    Globally, there has been a shift in the causes of illness and death from infectious diseases to noncommunicable diseases. This changing pattern has been attributed to the effects of an (ongoing) epidemiologic transition. Although researchers have applied epidemiologic transition theory to questions of global health, there have been relatively few…

  16. Epidemiology of Suicide Attempts among Youth Transitioning to Adulthood.

    Science.gov (United States)

    Thompson, Martie P; Swartout, Kevin

    2018-04-01

    Suicide is the second leading cause of death for older adolescents and young adults. Although empirical literature has identified important risk factors of suicidal behavior, it is less understood if changes in risk factors correspond with changes in suicide risk. To address this knowledge gap, we assessed if there were different trajectories of suicidal behavior as youth transition into young adulthood and determined what time-varying risk factors predicted these trajectories. This study used four waves of data spanning approximately 13 years from the National Longitudinal Study of Adolescent Health. The sample included 9027 respondents who were 12-18 years old (M = 15.26; SD = 1.76) at Wave 1, 50% male, 17% Hispanic, and 58% White. The results indicated that 93.6% of the sample had a low likelihood for suicide attempts across time, 5.1% had an elevated likelihood of attempting suicide in adolescence but not young adulthood, and 1.3% had an elevated likelihood of attempting suicide during adolescence and adulthood. The likelihood of a suicide attempt corresponded with changes on depression, impulsivity, delinquency, alcohol problems, family and friend suicide history, and experience with partner violence. Determining how suicide risk changes as youth transition into young adulthood and what factors predict these changes can help prevent suicide. Interventions targeting these risk factors could lead to reductions in suicide attempts.

  17. The urban health transition hypothesis: empirical evidence of an avian influenza Kuznets curve in Vietnam?

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    Spencer, James Herbert

    2013-04-01

    The literature on development has focused on the concept of transition in understanding the emergent challenges facing poor but rapidly developing countries. Scholars have focused extensively on the health and urban transitions associated with this change and, in particular, its use for understanding emerging infectious diseases. However, few have developed explicit empirical measures to quantify the extent to which a transitions focus is useful for theory, policy, and practice. Using open source data on avian influenza in 2004 and 2005 and the Vietnam Census of Population and Housing, this paper introduces the Kuznets curve as a tool for empirically estimating transition and disease. Findings suggest that the Kuznets curve is a viable tool for empirically assessing the role of transitional dynamics in the emergence of new infectious diseases.

  18. Demographic, epidemiological, and health transitions: are they relevant to population health patterns in Africa?

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    Barthélémy Kuate Defo

    2014-05-01

    Full Text Available Background: Studies of trends in population changes and epidemiological profiles in the developing world have overwhelmingly relied upon the concepts of demographic, epidemiological, and health transitions, even though their usefulness in describing and understanding population and health trends in developing countries has been repeatedly called into question. The issue is particularly relevant for the study of population health patterns in Africa and sub-Saharan Africa, as the history and experience there differs substantially from that of Western Europe and North America, for which these concepts were originally developed. Objective: The aim of this study is two-fold: to review and clarify any distinction between the concepts of demographic transition, epidemiological transition and health transition and to identify summary indicators of population health to test how well these concepts apply in Africa. Results: Notwithstanding the characteristically diverse African context, Africa is a continent of uncertainties and emergencies where discontinuities and interruptions of health, disease, and mortality trends reflect the enduring fragility and instability of countries and the vulnerabilities of individuals and populations in the continent. Africa as a whole remains the furthest behind the world's regions in terms of health improvements and longevity, as do its sub-Saharan African regions and societies specifically. This study documents: 1 theoretically and empirically the similarities and differences between the demographic transition, epidemiological transition, and health transition; 2 simple summary indicators that can be used to evaluate their descriptive and predictive features; 3 marked disparities in the onset and pace of variations and divergent trends in health, disease, and mortality patterns as well as fertility and life expectancy trajectories among African countries and regions over the past 60 years; 4 the rapid decline in infant

  19. Demographic, epidemiological, and health transitions: are they relevant to population health patterns in Africa?

    Science.gov (United States)

    Kuate Defo, Barthélémy

    2014-01-01

    Background Studies of trends in population changes and epidemiological profiles in the developing world have overwhelmingly relied upon the concepts of demographic, epidemiological, and health transitions, even though their usefulness in describing and understanding population and health trends in developing countries has been repeatedly called into question. The issue is particularly relevant for the study of population health patterns in Africa and sub-Saharan Africa, as the history and experience there differs substantially from that of Western Europe and North America, for which these concepts were originally developed. Objective The aim of this study is two-fold: to review and clarify any distinction between the concepts of demographic transition, epidemiological transition and health transition and to identify summary indicators of population health to test how well these concepts apply in Africa. Results Notwithstanding the characteristically diverse African context, Africa is a continent of uncertainties and emergencies where discontinuities and interruptions of health, disease, and mortality trends reflect the enduring fragility and instability of countries and the vulnerabilities of individuals and populations in the continent. Africa as a whole remains the furthest behind the world's regions in terms of health improvements and longevity, as do its sub-Saharan African regions and societies specifically. This study documents: 1) theoretically and empirically the similarities and differences between the demographic transition, epidemiological transition, and health transition; 2) simple summary indicators that can be used to evaluate their descriptive and predictive features; 3) marked disparities in the onset and pace of variations and divergent trends in health, disease, and mortality patterns as well as fertility and life expectancy trajectories among African countries and regions over the past 60 years; 4) the rapid decline in infant mortality and gains

  20. Demographic, epidemiological, and health transitions: are they relevant to population health patterns in Africa?

    Science.gov (United States)

    Kuate Defo, Barthélémy

    2014-01-01

    Studies of trends in population changes and epidemiological profiles in the developing world have overwhelmingly relied upon the concepts of demographic, epidemiological, and health transitions, even though their usefulness in describing and understanding population and health trends in developing countries has been repeatedly called into question. The issue is particularly relevant for the study of population health patterns in Africa and sub-Saharan Africa, as the history and experience there differs substantially from that of Western Europe and North America, for which these concepts were originally developed. The aim of this study is two-fold: to review and clarify any distinction between the concepts of demographic transition, epidemiological transition and health transition and to identify summary indicators of population health to test how well these concepts apply in Africa. Notwithstanding the characteristically diverse African context, Africa is a continent of uncertainties and emergencies where discontinuities and interruptions of health, disease, and mortality trends reflect the enduring fragility and instability of countries and the vulnerabilities of individuals and populations in the continent. Africa as a whole remains the furthest behind the world's regions in terms of health improvements and longevity, as do its sub-Saharan African regions and societies specifically. This study documents: 1) theoretically and empirically the similarities and differences between the demographic transition, epidemiological transition, and health transition; 2) simple summary indicators that can be used to evaluate their descriptive and predictive features; 3) marked disparities in the onset and pace of variations and divergent trends in health, disease, and mortality patterns as well as fertility and life expectancy trajectories among African countries and regions over the past 60 years; 4) the rapid decline in infant mortality and gains in life expectancy from the

  1. Stressful life transitions and wellbeing: A comparison of the stress buffering hypothesis and the social identity model of identity change.

    Science.gov (United States)

    Praharso, Nurul F; Tear, Morgan J; Cruwys, Tegan

    2017-01-01

    The relationship between stressful life transitions and wellbeing is well established, however, the protective role of social connectedness has received mixed support. We test two theoretical models, the Stress Buffering Hypothesis and the Social Identity Model of Identity Change, to determine which best explains the relationship between social connectedness, stress, and wellbeing. Study 1 (N=165) was an experiment in which participants considered the impact of moving cities versus receiving a serious health diagnosis. Study 2 (N=79) was a longitudinal study that examined the adjustment of international students to university over the course of their first semester. Both studies found limited evidence for the buffering role of social support as predicted by the Stress Buffering Hypothesis; instead people who experienced a loss of social identities as a result of a stressor had a subsequent decline in wellbeing, consistent with the Social Identity Model of Identity Change. We conclude that stressful life events are best conceptualised as identity transitions. Such events are more likely to be perceived as stressful and compromise wellbeing when they entail identity loss. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  2. Does rapid urbanization aggravate health disparities? Reflections on the epidemiological transition in Pune, India

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    Mareike Kroll

    2014-09-01

    Full Text Available Background: Rapid urbanization in low- and middle-income countries reinforces risk and epidemiological transition in urban societies, which are characterized by high socioeconomic gradients. Limited availability of disaggregated morbidity data in these settings impedes research on epidemiological profiles of different population subgroups. Objective: The study aimed to analyze the epidemiological transition in the emerging megacity of Pune with respect to changing morbidity and mortality patterns, also taking into consideration health disparities among different socioeconomic groups. Design: A mixed-methods approach was used, comprising secondary analysis of mortality data, a survey among 900 households in six neighborhoods with different socioeconomic profiles, 46 in-depth interviews with laypeople, and expert interviews with 37 health care providers and 22 other health care workers. Results: The mortality data account for an epidemiological transition with an increasing number of deaths due to non-communicable diseases (NCDs in Pune. The share of deaths due to infectious and parasitic diseases remained nearly constant, though the cause of deaths changed considerably within this group. The survey data and expert interviews indicated a slightly higher prevalence of diabetes and hypertension among higher socioeconomic groups, but a higher incidence and more frequent complications and comorbidities in lower socioeconomic groups. Although the self-reported morbidity for malaria, gastroenteritis, and tuberculosis did not show a socioeconomic pattern, experts estimated the prevalence in lower socioeconomic groups to be higher, though all groups in Pune would be affected. Conclusions: The rising burden of NCDs among all socioeconomic groups and the concurrent persistence of communicable diseases pose a major challenge for public health. Improvement of urban health requires a stronger focus on health promotion and disease prevention for all

  3. The Association of Dietary Fiber Intake with Cardiometabolic Risk in Four Countries across the Epidemiologic Transition

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    Louise Lie

    2018-05-01

    Full Text Available The greatest burden of cardiovascular disease is now carried by developing countries with cardiometabolic conditions such as metabolic syndrome, obesity and inflammation believed to be the driving force behind this epidemic. Dietary fiber is known to have protective effects against obesity, type 2 diabetes, cardiovascular disease and the metabolic syndrome. Considering the emerging prevalence of these cardiometabolic disease states across the epidemiologic transition, the objective of this study is to explore these associations of dietary fiber with cardiometabolic risk factors in four countries across the epidemiologic transition. We examined population-based samples of men and women, aged 25–45 of African origin from Ghana, Jamaica, the Seychelles and the USA. Ghanaians had the lowest prevalence of obesity (10%, while Jamaicans had the lowest prevalence of metabolic syndrome (5% across all the sites. Participants from the US presented with the highest prevalence of obesity (52%, and metabolic syndrome (22%. Overall, the Ghanaians consumed the highest dietary fiber (24.9 ± 9.7 g, followed by Jamaica (16.0 ± 8.3 g, the Seychelles (13.6 ± 7.2 g and the lowest in the USA (14.2 ± 7.1 g. Consequently, 43% of Ghanaians met the fiber dietary guidelines (14 g/1000 kcal/day, 9% of Jamaicans, 6% of Seychellois, and only 3% of US adults. Across all sites, cardiometabolic risk (metabolic syndrome, inflammation and obesity was inversely associated with dietary fiber intake, such that the prevalence of metabolic syndrome was 13% for those in the lowest quartile of fiber intake, compared to 9% those in the highest quartile of fiber intake. Notably, twice as many of participants (38% in the lowest quartile were obese compared to those in the highest quartile of fiber intake (18%. These findings further support the need to incorporate strategies and policies to promote increased dietary fiber intake as one component for the prevention of cardiometabolic

  4. Epidemiological transitions in maternal and child health in Peru: 1990–2013

    OpenAIRE

    C Watson, BS; G Kang, MPH; K Redican, PhD; K Abbas, PhD

    2015-01-01

    Background: Millennium Development Goal (MDG) 4 set the target of reducing the under-5 mortality rate by two-thirds between 1990 and 2015. MDG 5 set the target of reducing the maternal mortality ratio (MMR) by three-quarters over the same time period, and also achieve universal access to reproductive health. The objective of this study is to analyse the epidemiological transitions in maternal and child health in Peru from 1990 to 2013. Methods: We analysed the risk of child mortality by ag...

  5. Cardiovascular epidemiological transition in a rural habitat of Nigeria: the case of mangu local government area.

    Science.gov (United States)

    Okeahialam, B N; Ogbonna, C; Otokwula, A E; Joseph, D E; Chuhwak, E K; Isiguzoro, I O

    2012-01-01

    Epidemiological transition is at various stages in different places. The true situation in sub-Saharan Africa (SSA) is largely unknown. Having studied this rural habitat 17 years ago, we returned there to study several cardiovascular disease (CVD) risk factors to see if any change had occurred. The communities studied in 1991 as part of the national CVD survey were returned to in 2008 and re-studied descriptively in a cross-sectional manner. All adults 15 years and above, apart from demographic and personal data had blood pressure (BP) and some blood indices determined. Over the period, some changes occurred. The mean (SD) age increased from 34.1(16.9) to 45.5(18.2) years suggesting an ageing population. More people in 2008 than 1991 lived most of their last 5 years in the urban areas suggesting some influence of urbanisation. Significantly fewer people smoked and drank after 17 years. However mean (SD) of Body Mass Index rose [20.7(2.8) to 23.7(4.5) kg/m²], as well as SBP and DBP. Prevalence of hypertension rose from 7.4% to 20.9%. Both total and HDL cholesterol rose, although atherogenic index dropped. Mean (SD) blood sugar interestingly dropped from 5.0(2.9) to 4.6(1.0) mmol/l. Epidemiological transition is evident in this rural SSA habitat, and proactive steps to stem the tide and curb the consequences of CVD should be instituted.

  6. Mesenchymal-to-endothelial transition in Kaposi sarcoma: a histogenetic hypothesis based on a case series and literature review.

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    Simona Gurzu

    Full Text Available OBJECTIVES: Although several studies have been conducted regarding Kaposi sarcoma (KS, its histogenesis still remains to be elucidated. The aim of our study was to analyze the immunophenotype of Kaposi sarcoma and to present a hypothesis about the histogenesis of this tumor, based on a case series and a review of relevant literature. METHODS: In 15 cases of KSs diagnosed during 2000-2011, the clinicopathological features were correlated with the immunoexpression of c-Kit, SMA, CD34, CD31, vascular endothelial growth factor (VEGF, COX-2, c-KIT, smooth muscle antigen (SMA, and stem cell surface marker CD105. RESULTS: Both CD105 and c-KIT rate of the spindle-shaped tumor cell positivity increased in parallel to the pathological stage. All cases displayed CD105 and weak c-KIT positivity in the endothelial cells. SMA, VEGF, and COX-2 were focally expressed in all cases. CD34 marked both endothelium and spindle-shaped tumor cells. No c-KIT expression was noticed in KS of the internal organs. CONCLUSIONS: KS seems to be a variant of myofibroblastic tumors that originates from the viral modified pluripotent mesenchymal cells of the connective tissue transformed in spindle-shaped KS cells, followed by a mesenchymal-endothelial transition and a myofibroblastic-like differentiation. This paper mailnly showed that KS cannot be considered a pure vascular tumor.

  7. Essential evidence for guiding health system priorities and policies: anticipating epidemiological transition in Africa.

    Science.gov (United States)

    Byass, Peter; de Savigny, Don; Lopez, Alan D

    2014-01-01

    Despite indications that infection-related mortality in sub-Saharan Africa may be decreasing and the burden of non-communicable diseases increasing, the overwhelming reality is that health information systems across most of sub-Saharan Africa remain too weak to track epidemiological transition in a meaningful and effective way. We propose a minimum dataset as the basis of a functional health information system in countries where health information is lacking. This would involve continuous monitoring of cause-specific mortality through routine civil registration, regular documentation of exposure to leading risk factors, and monitoring effective coverage of key preventive and curative interventions in the health sector. Consideration must be given as to how these minimum data requirements can be effectively integrated within national health information systems, what methods and tools are needed, and ensuring that ethical and political issues are addressed. A more strategic approach to health information systems in sub-Saharan African countries, along these lines, is essential if epidemiological changes are to be tracked effectively for the benefit of local health planners and policy makers. African countries have a unique opportunity to capitalize on modern information and communications technology in order to achieve this. Methodological standards need to be established and political momentum fostered so that the African continent's health status can be reliably tracked. This will greatly strengthen the evidence base for health policies and facilitate the effective delivery of services.

  8. Essential evidence for guiding health system priorities and policies: anticipating epidemiological transition in Africa

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    Peter Byass

    2014-05-01

    Full Text Available Background: Despite indications that infection-related mortality in sub-Saharan Africa may be decreasing and the burden of non-communicable diseases increasing, the overwhelming reality is that health information systems across most of sub-Saharan Africa remain too weak to track epidemiological transition in a meaningful and effective way. Proposals: We propose a minimum dataset as the basis of a functional health information system in countries where health information is lacking. This would involve continuous monitoring of cause-specific mortality through routine civil registration, regular documentation of exposure to leading risk factors, and monitoring effective coverage of key preventive and curative interventions in the health sector. Consideration must be given as to how these minimum data requirements can be effectively integrated within national health information systems, what methods and tools are needed, and ensuring that ethical and political issues are addressed. A more strategic approach to health information systems in sub-Saharan African countries, along these lines, is essential if epidemiological changes are to be tracked effectively for the benefit of local health planners and policy makers. Conclusion: African countries have a unique opportunity to capitalize on modern information and communications technology in order to achieve this. Methodological standards need to be established and political momentum fostered so that the African continent's health status can be reliably tracked. This will greatly strengthen the evidence base for health policies and facilitate the effective delivery of services.

  9. Progression of the epidemiological transition in a rural South African setting: findings from population surveillance in Agincourt, 1993–2013

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    Chodziwadziwa W. Kabudula

    2017-05-01

    Full Text Available Abstract Background Virtually all low- and middle-income countries are undergoing an epidemiological transition whose progression is more varied than experienced in high-income countries. Observed changes in mortality and disease patterns reveal that the transition in most low- and middle-income countries is characterized by reversals, partial changes and the simultaneous occurrence of different types of diseases of varying magnitude. Localized characterization of this shifting burden, frequently lacking, is essential to guide decentralised health and social systems on the effective targeting of limited resources. Based on a rigorous compilation of mortality data over two decades, this paper provides a comprehensive assessment of the epidemiological transition in a rural South African population. Methods We estimate overall and cause-specific hazards of death as functions of sex, age and time period from mortality data from the Agincourt Health and socio-Demographic Surveillance System and conduct statistical tests of changes and differentials to assess the progression of the epidemiological transition over the period 1993–2013. Results From the early 1990s until 2007 the population experienced a reversal in its epidemiological transition, driven mostly by increased HIV/AIDS and TB related mortality. In recent years, the transition is following a positive trajectory as a result of declining HIV/AIDS and TB related mortality. However, in most age groups the cause of death distribution is yet to reach the levels it occupied in the early 1990s. The transition is also characterized by persistent gender differences with more rapid positive progression in females than males. Conclusions This typical rural South African population is experiencing a protracted epidemiological transition. The intersection and interaction of HIV/AIDS and antiretroviral treatment, non-communicable disease risk factors and complex social and behavioral changes will impact

  10. Cause-specific mortality trends in The Netherlands, 1875-1992: a formal analysis of the epidemiologic transition

    NARCIS (Netherlands)

    J.H. Wolleswinkel-van den Bosch (Judith); C.W.N. Looman (Caspar); F.W.A. van Poppel (Frans); J.P. Mackenbach (Johan)

    1997-01-01

    textabstractBACKGROUND: The objective of this study is to produce a detailed yet robust description of the epidemiologic transition in The Netherlands. METHODS: National mortality data on sex, age, cause of death and calendar year (1875-1992) were extracted from

  11. The epidemiologic transition of thalassemia and associated hemoglobinopathies in southern Taiwan.

    Science.gov (United States)

    Wang, Hui-Ching; Hsieh, Li-Ling; Liu, Yi-Chang; Hsiao, Hui-Hua; Lin, Shu-Kai; Tsai, Wen-Chan; Liu, Ta-Chih

    2017-02-01

    Since 1993, following the National Thalassemia Major Prevention Program and an increase in immigration and interracial marriages, especially in southern Taiwan, the distribution of hemoglobinopathies may have changed. This study investigates the epidemiologic transition of hemoglobinopathies. We analyzed 1870 specimens collected between 2003 and 2012 in southern Taiwan, used gap-polymerase chain reaction and PCR-restriction fragment length polymorphism-based methods, and confirmed genotypes of hemoglobinopathies by DNA sequencing. We found a 91% reduction in the incidence of thalassemia major compared with samples from between 1986 and 1995. The most common genotypes of α-thalassemia and α Hb variants were the SEA type (69.4%) and Hb Quong Sze (1.54%). The most common genotypes of β-thalassemia and β Hb variants were IVS-II-654 (46.2%) and Hb E (2.2%), respectively. Compared with studies performed in different areas of and time intervals in Taiwan, a higher prevalence of -α 3.7 , Hb Quong Sze, and Hb E and a lower prevalence of the SEA type were found in this study. However, the SEA type remained the most common genotype observed. In addition, an increasing number of cases with an -α 3.7 type carrier, Hb Quong Sze carrier, and G γ (A γ δβ)° were identified following a peak of interracial marriages between 2003 and 2005, reflecting a regional difference and the impact of interracial marriage. In conclusion, global migration and international marriage have changed the distribution of hemoglobinopathies in Taiwan. A more comprehensive prenatal screening for new immigrants with a longer follow-up is warranted.

  12. The epidemiological transition in Antananarivo, Madagascar: an assessment based on death registers (1900–2012

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    Bruno Masquelier

    2014-05-01

    Full Text Available Background: Madagascar today has one of the highest life expectancies in sub-Saharan Africa, despite being among the poorest countries in the continent. There are relatively few detailed accounts of the epidemiological transition in this country due to the lack of a comprehensive death registration system at the national level. However, in Madagascar's capital city, death registration was established around the start of the 20th century and is now considered virtually complete. Objective: We provide an overview of trends in all-cause and cause-specific mortality in Antananarivo to document the timing and pace of the mortality decline and the changes in the cause-of-death structure. Design: Death registers covering the period 1976–2012 were digitized and the population at risk of dying was estimated from available censuses and surveys. Trends for the period 1900–1976 were partly reconstructed from published sources. Results: The crude death rate stagnated around 30‰ until the 1940s in Antananarivo. Mortality declined rapidly after the World War II and then resurged again in the 1980s as a result of the re-emergence of malaria and the collapse of Madagascar's economy. Over the past 30 years, impressive gains in life expectancy have been registered thanks to the unabated decline in child mortality, despite political instability, a lasting economic crisis and the persistence of high rates of chronic malnutrition. Progress in adult survival has been more modest because reductions in infectious diseases and diseases of the respiratory system have been partly offset by increases in cardiovascular diseases, neoplasms, and other diseases, particularly at age 50 years and over. Conclusions: The transition in Antananarivo has been protracted and largely dependent on anti-microbial and anti-parasitic medicine. The capital city now faces a double burden of communicable and non-communicable diseases. The ongoing registration of deaths in the capital

  13. [Epidemiological transition of mycosis diseases in sub-Saharan Africa: from surface to depth].

    Science.gov (United States)

    Chandenier, J; Desoubeaux, G

    2015-02-01

    Fungi are schematically responsible for three distinct kinds of infections: superficial mycoses, subcutaneous and deep ones. The current socio-epidemiological transition observed in sub-Saharan Africa does not actually lead to similar consequences regarding these three categories of fungal entities. For instance, it has long been known that superficial mycoses are very prevalent in tropical areas, since they are partly due to the warm climate and the promiscuity. They are mostly caused by dermatophytic fungi or Malassezia sp. (Pityriasis versicolor). Subcutaneous mycoses are rarer, and usually due to dimorphic fungi which are accidentally inoculated into the body after a skin injury or a trauma. Sometimes very spectacular, the clinical outcome is then described as chronic. Thus, chromoblastomycosis, rhinoentomophtoromycosis or mycetoma are some examples of subcutaneous mycoses which remain well-known by practitioners of endemic countries. Deep mycoses (or invasive / systemic mycoses) are defined by fungal infections of deep anatomical sites that should be normally sterile. By contrast with the other entities mentioned above, the outcome may be rapidly fatal for the patient. One of the most outstanding examples was the great increasing of cryptococcal meningitis during the HIV outbreak in the 80'. A few other similar mycoses may be feared in a near future, since they usually occur in contexts of important immunosuppression which are about to be definitely experienced in Africa: overall increase of chronic diseases like diabetes, lengthening life expectancy and its associated diseases, widespread medical practices which were only seen in advanced intensive care units, onco-haematology departments or graft centers so far. Thus, the deep mycoses will inevitably increase in Africa, as they did in all developed countries over the last two decades. The consequences will not only be limited to the clinical management as described above: the diagnostic approach is also

  14. Child and Adolescent Mortality Across Malaysia's Epidemiological Transition: A Systematic Analysis of Global Burden of Disease Data.

    Science.gov (United States)

    Abdul-Razak, Suraya; Azzopardi, Peter S; Patton, George C; Mokdad, Ali H; Sawyer, Susan M

    2017-10-01

    A rapid epidemiological transition in developing countries in Southeast Asia has been accompanied by major shifts in the health status of children and adolescents. In this article, mortality estimates in Malaysian children and adolescents from 1990 to 2013 are used to illustrate these changes. All-cause and cause-specific mortality estimates were obtained from the 2013 Global Burden of Disease Study. Data were extracted from 1990 to 2013 for the developmental age range from 1 to 24 years, for both sexes. Trends in all-cause and cause-specific mortality for the major epidemiological causes were estimated. From 1990 to 2013, all-cause mortality decreased in all age groups. Reduction of all-cause mortality was greatest in 1- to 4-year-olds (2.4% per year reduction) and least in 20- to 24-year-olds (.9% per year reduction). Accordingly, in 2013, all-cause mortality was highest in 20- to 24-year-old males (129 per 100,000 per year). In 1990, the principal cause of death for 1- to 9-year boys and girls was vaccine preventable diseases. By 2013, neoplasms had become the major cause of death in 1-9 year olds of both sexes. The major cause of death in 10- to 24-year-old females was typhoid in 1990 and neoplasms in 2013, whereas the major cause of death in 10- to 24-year-old males remained road traffic injuries. The reduction in mortality across the epidemiological transition in Malaysia has been much less pronounced for adolescents than younger children. The contribution of injuries and noncommunicable diseases to adolescent mortality suggests where public health strategies should focus. Copyright © 2017 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  15. Transitions between central and peripheral vision create spatial/temporal distortions: a hypothesis concerning the perceived break of the curveball.

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    Arthur Shapiro

    2010-10-01

    Full Text Available The human visual system does not treat all parts of an image equally: the central segments of an image, which fall on the fovea, are processed with a higher resolution than the segments that fall in the visual periphery. Even though the differences between foveal and peripheral resolution are large, these differences do not usually disrupt our perception of seamless visual space. Here we examine a motion stimulus in which the shift from foveal to peripheral viewing creates a dramatic spatial/temporal discontinuity.The stimulus consists of a descending disk (global motion with an internal moving grating (local motion. When observers view the disk centrally, they perceive both global and local motion (i.e., observers see the disk's vertical descent and the internal spinning. When observers view the disk peripherally, the internal portion appears stationary, and the disk appears to descend at an angle. The angle of perceived descent increases as the observer views the stimulus from further in the periphery. We examine the first- and second-order information content in the display with the use of a three-dimensional Fourier analysis and show how our results can be used to describe perceived spatial/temporal discontinuities in real-world situations.The perceived shift of the disk's direction in the periphery is consistent with a model in which foveal processing separates first- and second-order motion information while peripheral processing integrates first- and second-order motion information. We argue that the perceived distortion may influence real-world visual observations. To this end, we present a hypothesis and analysis of the perception of the curveball and rising fastball in the sport of baseball. The curveball is a physically measurable phenomenon: the imbalance of forces created by the ball's spin causes the ball to deviate from a straight line and to follow a smooth parabolic path. However, the curveball is also a perceptual puzzle

  16. Transitions between central and peripheral vision create spatial/temporal distortions: a hypothesis concerning the perceived break of the curveball.

    Science.gov (United States)

    Shapiro, Arthur; Lu, Zhong-Lin; Huang, Chang-Bing; Knight, Emily; Ennis, Robert

    2010-10-13

    The human visual system does not treat all parts of an image equally: the central segments of an image, which fall on the fovea, are processed with a higher resolution than the segments that fall in the visual periphery. Even though the differences between foveal and peripheral resolution are large, these differences do not usually disrupt our perception of seamless visual space. Here we examine a motion stimulus in which the shift from foveal to peripheral viewing creates a dramatic spatial/temporal discontinuity. The stimulus consists of a descending disk (global motion) with an internal moving grating (local motion). When observers view the disk centrally, they perceive both global and local motion (i.e., observers see the disk's vertical descent and the internal spinning). When observers view the disk peripherally, the internal portion appears stationary, and the disk appears to descend at an angle. The angle of perceived descent increases as the observer views the stimulus from further in the periphery. We examine the first- and second-order information content in the display with the use of a three-dimensional Fourier analysis and show how our results can be used to describe perceived spatial/temporal discontinuities in real-world situations. The perceived shift of the disk's direction in the periphery is consistent with a model in which foveal processing separates first- and second-order motion information while peripheral processing integrates first- and second-order motion information. We argue that the perceived distortion may influence real-world visual observations. To this end, we present a hypothesis and analysis of the perception of the curveball and rising fastball in the sport of baseball. The curveball is a physically measurable phenomenon: the imbalance of forces created by the ball's spin causes the ball to deviate from a straight line and to follow a smooth parabolic path. However, the curveball is also a perceptual puzzle because batters often

  17. Epidemiology of malaria in the forest-savanna transitional zone of Ghana

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    Newton Sam

    2009-09-01

    Full Text Available Abstract Background Information on the epidemiology of malaria is essential for designing and interpreting results of clinical trials of drugs, vaccines and other interventions. As a background to the establishment of a site for anti-malarial drugs and vaccine trials, the epidemiology of malaria in a rural site in central Ghana was investigated. Methods Active surveillance of clinical malaria was carried out in a cohort of children below five years of age (n = 335 and the prevalence of malaria was estimated in a cohort of subjects of all ages (n = 1484 over a 12-month period. Participants were sampled from clusters drawn around sixteen index houses randomly selected from a total of about 22,000 houses within the study area. The child cohort was visited thrice weekly to screen for any illness and a blood slide was taken if a child had a history of fever or a temperature greater than or equal to 37.5 degree Celsius. The all-age cohort was screened for malaria once every eight weeks over a 12-month period. Estimation of Entomological Inoculation Rate (EIR and characterization of Anopheline malaria vectors in the study area were also carried out. Results The average parasite prevalence in the all age cohort was 58% (95% CI: 56.9, 59.4. In children below five years of age, the average prevalence was 64% (95% CI: 61.9, 66.0. Geometric mean parasite densities decreased significantly with increasing age. More than 50% of all children less than 10 years of age were anaemic. Children less than 5 years of age had as many as seven malaria attacks per child per year. The attack rates decreased significantly with increasing cut-offs of parasite density. The average Multiplicity of Infection (MOI was of 6.1. All three pyrimethamine resistance mutant alleles of the Plasmodium falciparum dhfr gene were prevalent in this population and 25% of infections had a fourth mutant of pfdhps-A437G. The main vectors were Anopheles funestus and Anopheles gambiae and the EIR

  18. DEMOGRAPHIC POLICY AND THE ANALYSIS OF IRRETRIEVABLE LOSSES OF PUBLIC HEALTH BASED ON THE CONCEPT OF THE EPIDEMIOLOGICAL TRANSITION

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    Юрий Аркадьевич Григорьев

    2017-09-01

    Full Text Available From the general positions of population dynamics, the demographic policy is considered, its regional features in the East of Russia are designated. It is necessary to consolidate the positive traditions of the moral and legal norms of the society and the harmonious personality development. It takes their long-term translation for the improvement of the person himself, his family-marriage relations to support the forms of demographic behavior aimed at the expanded population reproduction. The solution of the numerous tasks of the demographic policy presupposes further scientific (theoretical and applied studies of the features of the socio-demographic and medico-demographic development of the Russian regions. Particular attention should be paid to the analysis of the main characteristics of the epidemiological transition, where mortality, as well as birth rate, is one of the main characteristics of the population reproduction. This will make it possible to define more precisely the prediction of the value of irretrievable losses with endogenous and exogenous determination, to estimate on this basis the reserves of increasing life expectancy through the measures of demographic policy.

  19. Mortality in Catalonia in the context of the third, fourth and future phases of the epidemiological transition theory

    Directory of Open Access Journals (Sweden)

    2009-02-01

    Full Text Available In the period 1960-2000, male and female life expectancy increased by 8,2 and 10,5 years, respectively, in Catalonia, one of Spain's Autonomous Regions, to one of the highest in the world. Initially, most gains were due to lower infant mortality, but as cardiovascular diseases declined this later shifted to advanced ages. Between the mid-1980s and early 1990s life expectancy improvements stagnated as the mortality risk from traffic accidents and HIV/AIDS in young adults increased. Both the age-delay in old-age mortality and the simultaneous influence of behaviour and life style reflect distinct aspects of the fourth stage of the epidemiological transition. This analysis quantifies the age and cause of death contributions to changes and sex-differences in life expectancy in Catalonia. It subsequently compares the most recent life table for women with the Duchene-Wunsch limited life table to estimate the potential gain in life expectancy when all deaths would be ageing-related and on which ages these improvements would fall.

  20. La hipótesis de la compresión de la morbilidad: un ejemplo de desarrollo teórico en epidemiología The hypothesis of the compression of morbidity: an example of theoretical development in epidemiology

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    Sergio López-Moreno

    1998-09-01

    Full Text Available En este documento se revisa la hipótesis de la compresión de la morbilidad, propuesta por James Fries en 1980, como un ejemplo de elaboración teórica en el campo de la epidemiología. Se presentan inicialmente algunos rasgos fundamentales de las teorías científicas y se hace un recuento histórico de los modelos causales más importantes que ha utilizado la epidemiología. Posteriormente, se presentan los fundamentos de la hipótesis de la compresión de la morbilidad, y se examinan sus posibilidades y limitaciones actuales, así como sus implicaciones epistemológicas con base en la teoría estructuralista. Se concluye que si el modelo de la compresión de la morbilidad fuera correcto, tendría una enorme capacidad para describir, explicar y predecir la salud y la enfermedad en las poblaciones humanas; por lo tanto, el desarrollo sistemático de este tipo de propuestas tiene una extraordinaria importancia para la salud pública.In this paper we review a hypothesis put forth in 1980 by James Fries under the name of the compression of morbidity, as an example of theoretical development in the field of epidemiology. Initially we discuss some of the essential features of scientific theories and make a historical account of the most important causal models that epidemiology has embraced. Then, the basis for proposing that a compression of the morbidity is taking place are described focusing on its advantages and limitations when it is analyzed from the point of view of structuralism. Finally, we conclude that, to the extent that they are correct, models of this kind have the potential of describing and predicting the evolution of human health; hence, their systematic development entails an extraordinary importance for public health.

  1. The social patterning of risk factors for noncommunicable diseases in five countries: evidence from the modeling the epidemiologic transition study (METS

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    Silvia Stringhini

    2016-09-01

    Full Text Available Abstract Background Associations between socioeconomic status (SES and risk factors for noncommunicable diseases (NCD-RFs may differ in populations at different stages of the epidemiological transition. We assessed the social patterning of NCD-RFs in a study including populations with different levels of socioeconomic development. Methods Data on SES, smoking, physical activity, body mass index, blood pressure, cholesterol and glucose were available from the Modeling the Epidemiologic Transition Study (METS, with about 500 participants aged 25–45 in each of five sites (Ghana, South Africa, Jamaica, Seychelles, United States. Results The prevalence of NCD-RFs differed between these populations from five countries (e.g., lower prevalence of smoking, obesity and hypertension in rural Ghana and by sex (e.g., higher prevalence of smoking and physical activity in men and of obesity in women in most populations. Smoking and physical activity were associated with low SES in most populations. The associations of SES with obesity, hypertension, cholesterol and elevated blood glucose differed by population, sex, and SES indicator. For example, the prevalence of elevated blood glucose tended to be associated with low education, but not with wealth, in Seychelles and USA. The association of SES with obesity and cholesterol was direct in some populations but inverse in others. Conclusions In conclusion, the distribution of NCD-RFs was socially patterned in these populations at different stages of the epidemiological transition, but associations between SES and NCD-RFs differed substantially according to risk factor, population, sex, and SES indicator. These findings emphasize the need to assess and integrate the social patterning of NCD-RFs in NCD prevention and control programs in LMICs.

  2. The evolutionary transition from subsocial to eusocial behaviour in Dictyoptera: phylogenetic evidence for modification of the "shift-in-dependent-care" hypothesis with a new subsocial cockroach.

    Science.gov (United States)

    Pellens, Roseli; D'Haese, Cyrille A; Bellés, Xavier; Piulachs, Maria-Dolors; Legendre, Frédéric; Wheeler, Ward C; Grandcolas, Philippe

    2007-05-01

    Cockroaches have always been used to understand the first steps of social evolution in termites because they are close relatives with less complex and integrated social behaviour. Termites are all eusocial and ingroup comparative analysis would be useless to infer the origin of their social behaviour. The cockroach genus Cryptocercus was used as a so-called "prototermite" model because it shows key-attributes similar to the termites (except Termitidae): wood-feeding, intestinal flagellates and subsocial behaviour. In spite of these comparisons between this subsocial cockroach and eusocial termites, the early and remote origin of eusocial behaviour in termites is not well understood yet and the study of other relevant "prototermite" models is however needed. A molecular phylogenetic analysis was carried out to validate a new "prototermite" model, Parasphaeria boleiriana which shows a peculiar combination of these key-attributes. It shows that these attributes of Parasphaeria boleiriana have an independent origin from those of other wood-eating cockroaches and termites. The case of P. boleiriana suggests that a short brood care was selected for with life on an ephemeral wood resource, even with the need for transmission of flagellates. These new phylogenetic insights modify evolutionary hypotheses, contradicting the assumption made with Cryptocercus model that a long brood care is necessary for cooperation between broods in the "shift-in-dependent-care" hypothesis. An ephemeral wood resource is suggested to prompt generation overlap and the evolution of cooperation, even if brood care is shortened.

  3. TRANSIT

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. TRANSIT. SYSTEM: DETERMINE 2D-POSITION GLOBALLY BUT INTERMITTENT (POST-FACTO). IMPROVED ACCURACY. PRINCIPLE: POLAR SATELLITES WITH INNOVATIONS OF: GRAVITY-GRADIENT ATTITUDE CONTROL; DRAG COMPENSATION. WORKS ...

  4. La transición epidemiológica de las y los adolescentes en México The epidemiologic transition among adolescents in Mexico

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    José Ignacio Santos-Preciado

    2003-01-01

    performed in order to asses the impact of the epidemiologic transition on the availability and priority of health services for adolescents. The Omran epidemiologic model was used to classify the demographic, social and economic characteristics of Mexican adolescents in efforts to define their impact on the epidemiologic transition of this age group. RESULTS: Demographic data are presented in the perspective of the epidemiologic transition which permit us to make inferences on the social conditions , growth patterns and health needs of this age group in Mexico. Data are presented regarding the demand and availability of health services, the impact of education and employment opportunities and the role of family and the economy on their well being. Other important aspects presented include the role of education on the sexual and reproductive health of adolescents and the threat of the AIDS pandemic in this age group. CONCLUSIONS: These findings reveal a sequence of variables that can no longer be addressed in the traditional problem oriented approach and strongly suggest a need to profile the health needs of adolescents in an integrated, holistic fashion with emphasis in health promotion and healthy life styles to favor their integral, just and equitable development, and also help focus the societal response in an integrated manner.

  5. Geriatric teaching in Brazilian medical schools in 2013 and considerations regarding adjustment to demographic and epidemiological transition

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    Ana Conceição Norbim Prado Cunha

    2016-04-01

    Full Text Available Summary Objective: This study aims to describe the profile of medical schools that introduced courses on Geriatrics and Elderly Health or Aging in their curriculum, and compare such information with the age distribution and health epidemiological data of the Brazilian population, using data until the year of 2013. Methods: 180 universities offering medical undergraduate courses and registered with the Ministry of Education and Culture of Brazil (MEC were found, as seen on the MEC website (www.emec.mec.gov.br in February 2013. Based on the list of institutions, the authors created a database. Results: Brazil's Southeast region is the one presenting most of the courses, both offered as core or elective subjects, in the area of Geriatrics. The Midwest region had the least offer of Geriatrics and Elderly Health and Care courses. The Southeast region presents the greater absolute number of institutions with elective subjects, followed by the South and Northeast regions, each with a single institution. The Southeast region was at the same time the one that presented the biggest absolute number of institutions offering core subjects in the area of Geriatrics, being followed by the Northeast, South, North, and Midwest regions. Conclusion: By analyzing the availability of courses that emphasize aging and Geriatrics in brazilian medical schools, the present study reveals that specialized training should be encouraged with respect to the specificities of health care given to the elderly population, which has a higher frequency of chronic and degenerative diseases.

  6. THE FRACTAL MARKET HYPOTHESIS

    OpenAIRE

    FELICIA RAMONA BIRAU

    2012-01-01

    In this article, the concept of capital market is analysed using Fractal Market Hypothesis which is a modern, complex and unconventional alternative to classical finance methods. Fractal Market Hypothesis is in sharp opposition to Efficient Market Hypothesis and it explores the application of chaos theory and fractal geometry to finance. Fractal Market Hypothesis is based on certain assumption. Thus, it is emphasized that investors did not react immediately to the information they receive and...

  7. Variability: A Pernicious Hypothesis.

    Science.gov (United States)

    Noddings, Nel

    1992-01-01

    The hypothesis of greater male variability in test results is discussed in its historical context, and reasons feminists have objected to the hypothesis are considered. The hypothesis acquires political importance if it is considered that variability results from biological, rather than cultural, differences. (SLD)

  8. THE FRACTAL MARKET HYPOTHESIS

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    FELICIA RAMONA BIRAU

    2012-05-01

    Full Text Available In this article, the concept of capital market is analysed using Fractal Market Hypothesis which is a modern, complex and unconventional alternative to classical finance methods. Fractal Market Hypothesis is in sharp opposition to Efficient Market Hypothesis and it explores the application of chaos theory and fractal geometry to finance. Fractal Market Hypothesis is based on certain assumption. Thus, it is emphasized that investors did not react immediately to the information they receive and of course, the manner in which they interpret that information may be different. Also, Fractal Market Hypothesis refers to the way that liquidity and investment horizons influence the behaviour of financial investors.

  9. Association of car ownership and physical activity across the spectrum of human development: Modeling the Epidemiologic Transition Study (METS).

    Science.gov (United States)

    Shoham, David A; Dugas, Lara R; Bovet, Pascal; Forrester, Terrence E; Lambert, Estelle V; Plange-Rhule, Jacob; Schoeller, Dale A; Brage, Soren; Ekelund, Ulf; Durazo-Arvizu, Ramon A; Cooper, Richard S; Luke, Amy

    2015-02-21

    Variations in physical activity (PA) across nations may be driven by socioeconomic position. As national incomes increase, car ownership becomes within reach of more individuals. This report characterizes associations between car ownership and PA in African-origin populations across 5 sites at different levels of economic development and with different transportation infrastructures: US, Seychelles, Jamaica, South Africa, and Ghana. Twenty-five hundred adults, ages 25-45, were enrolled in the study. A total of 2,101 subjects had valid accelerometer-based PA measures (reported as average daily duration of moderate to vigorous PA, MVPA) and complete socioeconomic information. Our primary exposure of interest was whether the household owned a car. We adjusted for socioeconomic position using household income and ownership of common goods. Overall, PA levels did not vary largely between sites, with highest levels in South Africa, lowest in the US. Across all sites, greater PA was consistently associated with male gender, fewer years of education, manual occupations, lower income, and owning fewer material goods. We found heterogeneity across sites in car ownership: after adjustment for confounders, car owners in the US had 24.3 fewer minutes of MVPA compared to non-car owners in the US (20.7 vs. 45.1 minutes/day of MVPA); in the non-US sites, car-owners had an average of 9.7 fewer minutes of MVPA than non-car owners (24.9 vs. 34.6 minutes/day of MVPA). PA levels are similar across all study sites except Jamaica, despite very different levels of socioeconomic development. Not owning a car in the US is associated with especially high levels of MVPA. As car ownership becomes prevalent in the developing world, strategies to promote alternative forms of active transit may become important.

  10. Profesi Epidemiologi

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    Buchari Lapau

    2011-01-01

    Full Text Available Makalah ini pertama kali menjelaskan perlu adanya profesi kesehatan masyarakat dalam rangka pembangunan kesehatan. Lalu dijelaskan apa profesi itu dan standar keberadaan profesi, atas dasar mana dapat ditetapkan bahwa pelayanan epidemiologi merupakan salah satu profesi. Dalam rangka pembinaan profesi kesehatan masyarakat, IAKMI dan APTKMI telah membentuk Majelis Kolegium Kesehatan Masyarakat Indonesia (MKKMI yang terdiri atas 8 kolegium antara lain Kolegium Epidemiologi, yang telah menyusun Standar Profesi Epidemiologi yang terdiri atas beberapa standar. Masing-masing standar dijelaskan mulai dari kurikulum, standar pelayanan epidmiologi, profil epidemiolog kesehatan, peran epidemiolog kesehatan, fungsi epidemiolog kesehatan, standar kompetensi epidemiologi, dan standar pendidikan profesi epidemiologi.

  11. Physiopathological Hypothesis of Cellulite

    Science.gov (United States)

    de Godoy, José Maria Pereira; de Godoy, Maria de Fátima Guerreiro

    2009-01-01

    A series of questions are asked concerning this condition including as regards to its name, the consensus about the histopathological findings, physiological hypothesis and treatment of the disease. We established a hypothesis for cellulite and confirmed that the clinical response is compatible with this hypothesis. Hence this novel approach brings a modern physiological concept with physiopathologic basis and clinical proof of the hypothesis. We emphasize that the choice of patient, correct diagnosis of cellulite and the technique employed are fundamental to success. PMID:19756187

  12. Life Origination Hydrate Hypothesis (LOH-Hypothesis

    Directory of Open Access Journals (Sweden)

    Victor Ostrovskii

    2012-01-01

    Full Text Available The paper develops the Life Origination Hydrate Hypothesis (LOH-hypothesis, according to which living-matter simplest elements (LMSEs, which are N-bases, riboses, nucleosides, nucleotides, DNA- and RNA-like molecules, amino-acids, and proto-cells repeatedly originated on the basis of thermodynamically controlled, natural, and inevitable processes governed by universal physical and chemical laws from CH4, niters, and phosphates under the Earth's surface or seabed within the crystal cavities of the honeycomb methane-hydrate structure at low temperatures; the chemical processes passed slowly through all successive chemical steps in the direction that is determined by a gradual decrease in the Gibbs free energy of reacting systems. The hypothesis formulation method is based on the thermodynamic directedness of natural movement and consists ofan attempt to mentally backtrack on the progression of nature and thus reveal principal milestones alongits route. The changes in Gibbs free energy are estimated for different steps of the living-matter origination process; special attention is paid to the processes of proto-cell formation. Just the occurrence of the gas-hydrate periodic honeycomb matrix filled with LMSEs almost completely in its final state accounts for size limitation in the DNA functional groups and the nonrandom location of N-bases in the DNA chains. The slowness of the low-temperature chemical transformations and their “thermodynamic front” guide the gross process of living matter origination and its successive steps. It is shown that the hypothesis is thermodynamically justified and testable and that many observed natural phenomena count in its favor.

  13. Protocol for the modeling the epidemiologic transition study: a longitudinal observational study of energy balance and change in body weight, diabetes and cardiovascular disease risk

    Directory of Open Access Journals (Sweden)

    Luke Amy

    2011-12-01

    Full Text Available Abstract Background The prevalence of obesity has increased in societies of all socio-cultural backgrounds. To date, guidelines set forward to prevent obesity have universally emphasized optimal levels of physical activity. However there are few empirical data to support the assertion that low levels of energy expenditure in activity is a causal factor in the current obesity epidemic are very limited. Methods/Design The Modeling the Epidemiologic Transition Study (METS is a cohort study designed to assess the association between physical activity levels and relative weight, weight gain and diabetes and cardiovascular disease risk in five population-based samples at different stages of economic development. Twenty-five hundred young adults, ages 25-45, were enrolled in the study; 500 from sites in Ghana, South Africa, Seychelles, Jamaica and the United States. At baseline, physical activity levels were assessed using accelerometry and a questionnaire in all participants and by doubly labeled water in a subsample of 75 per site. We assessed dietary intake using two separate 24-hour recalls, body composition using bioelectrical impedance analysis, and health history, social and economic indicators by questionnaire. Blood pressure was measured and blood samples collected for measurement of lipids, glucose, insulin and adipokines. Full examination including physical activity using accelerometry, anthropometric data and fasting glucose will take place at 12 and 24 months. The distribution of the main variables and the associations between physical activity, independent of energy intake, glucose metabolism and anthropometric measures will be assessed using cross-section and longitudinal analysis within and between sites. Discussion METS will provide insight on the relative contribution of physical activity and diet to excess weight, age-related weight gain and incident glucose impairment in five populations' samples of young adults at different stages

  14. Cardiovascular risk status of Afro-origin populations across the spectrum of economic development: findings from the Modeling the Epidemiologic Transition Study.

    Science.gov (United States)

    Dugas, Lara R; Forrester, Terrence E; Plange-Rhule, Jacob; Bovet, Pascal; Lambert, Estelle V; Durazo-Arvizu, Ramon A; Cao, Guichan; Cooper, Richard S; Khatib, Rasha; Tonino, Laura; Riesen, Walter; Korte, Wolfgang; Kliethermes, Stephanie; Luke, Amy

    2017-05-12

    Cardiovascular risk factors are increasing in most developing countries. To date, however, very little standardized data has been collected on the primary risk factors across the spectrum of economic development. Data are particularly sparse from Africa. In the Modeling the Epidemiologic Transition Study (METS) we examined population-based samples of men and women, ages 25-45 of African ancestry in metropolitan Chicago, Kingston, Jamaica, rural Ghana, Cape Town, South Africa, and the Seychelles. Key measures of cardiovascular disease risk are described. The risk factor profile varied widely in both total summary estimates of cardiovascular risk and in the magnitude of component factors. Hypertension ranged from 7% in women from Ghana to 35% in US men. Total cholesterol was well under 200 mg/dl for all groups, with a mean of 155 mg/dl among men in Ghana, South Africa and Jamaica. Among women total cholesterol values varied relatively little by country, following between 160 and 178 mg/dl for all 5 groups. Levels of HDL-C were virtually identical in men and women from all study sites. Obesity ranged from 64% among women in the US to 2% among Ghanaian men, with a roughly corresponding trend in diabetes. Based on the Framingham risk score a clear trend toward higher total risk in association with socioeconomic development was observed among men, while among women there was considerable overlap, with the US participants having only a modestly higher risk score. These data provide a comprehensive estimate of cardiovascular risk across a range of countries at differing stages of social and economic development and demonstrate the heterogeneity in the character and degree of emerging cardiovascular risk. Severe hypercholesterolemia, as characteristic in the US and much of Western Europe at the onset of the coronary epidemic, is unlikely to be a feature of the cardiovascular risk profile in these countries in the foreseeable future, suggesting that stroke may remain the

  15. Hypothesis analysis methods, hypothesis analysis devices, and articles of manufacture

    Science.gov (United States)

    Sanfilippo, Antonio P [Richland, WA; Cowell, Andrew J [Kennewick, WA; Gregory, Michelle L [Richland, WA; Baddeley, Robert L [Richland, WA; Paulson, Patrick R [Pasco, WA; Tratz, Stephen C [Richland, WA; Hohimer, Ryan E [West Richland, WA

    2012-03-20

    Hypothesis analysis methods, hypothesis analysis devices, and articles of manufacture are described according to some aspects. In one aspect, a hypothesis analysis method includes providing a hypothesis, providing an indicator which at least one of supports and refutes the hypothesis, using the indicator, associating evidence with the hypothesis, weighting the association of the evidence with the hypothesis, and using the weighting, providing information regarding the accuracy of the hypothesis.

  16. On the Keyhole Hypothesis

    DEFF Research Database (Denmark)

    Mikkelsen, Kaare B.; Kidmose, Preben; Hansen, Lars Kai

    2017-01-01

    simultaneously recorded scalp EEG. A cross-validation procedure was employed to ensure unbiased estimates. We present several pieces of evidence in support of the keyhole hypothesis: There is a high mutual information between data acquired at scalp electrodes and through the ear-EEG "keyhole," furthermore we......We propose and test the keyhole hypothesis that measurements from low dimensional EEG, such as ear-EEG reflect a broadly distributed set of neural processes. We formulate the keyhole hypothesis in information theoretical terms. The experimental investigation is based on legacy data consisting of 10...

  17. Cardiovascular risk status of Afro-origin populations across the spectrum of economic development: findings from the Modeling the Epidemiologic Transition Study

    Directory of Open Access Journals (Sweden)

    Lara R. Dugas

    2017-05-01

    Full Text Available Abstract Background Cardiovascular risk factors are increasing in most developing countries. To date, however, very little standardized data has been collected on the primary risk factors across the spectrum of economic development. Data are particularly sparse from Africa. Methods In the Modeling the Epidemiologic Transition Study (METS we examined population-based samples of men and women, ages 25–45 of African ancestry in metropolitan Chicago, Kingston, Jamaica, rural Ghana, Cape Town, South Africa, and the Seychelles. Key measures of cardiovascular disease risk are described. Results The risk factor profile varied widely in both total summary estimates of cardiovascular risk and in the magnitude of component factors. Hypertension ranged from 7% in women from Ghana to 35% in US men. Total cholesterol was well under 200 mg/dl for all groups, with a mean of 155 mg/dl among men in Ghana, South Africa and Jamaica. Among women total cholesterol values varied relatively little by country, following between 160 and 178 mg/dl for all 5 groups. Levels of HDL-C were virtually identical in men and women from all study sites. Obesity ranged from 64% among women in the US to 2% among Ghanaian men, with a roughly corresponding trend in diabetes. Based on the Framingham risk score a clear trend toward higher total risk in association with socioeconomic development was observed among men, while among women there was considerable overlap, with the US participants having only a modestly higher risk score. Conclusions These data provide a comprehensive estimate of cardiovascular risk across a range of countries at differing stages of social and economic development and demonstrate the heterogeneity in the character and degree of emerging cardiovascular risk. Severe hypercholesterolemia, as characteristic in the US and much of Western Europe at the onset of the coronary epidemic, is unlikely to be a feature of the cardiovascular risk profile in these

  18. The Qualitative Expectations Hypothesis

    DEFF Research Database (Denmark)

    Frydman, Roman; Johansen, Søren; Rahbek, Anders

    2017-01-01

    We introduce the Qualitative Expectations Hypothesis (QEH) as a new approach to modeling macroeconomic and financial outcomes. Building on John Muth's seminal insight underpinning the Rational Expectations Hypothesis (REH), QEH represents the market's forecasts to be consistent with the predictions...... of an economistís model. However, by assuming that outcomes lie within stochastic intervals, QEH, unlike REH, recognizes the ambiguity faced by an economist and market participants alike. Moreover, QEH leaves the model open to ambiguity by not specifying a mechanism determining specific values that outcomes take...

  19. The Qualitative Expectations Hypothesis

    DEFF Research Database (Denmark)

    Frydman, Roman; Johansen, Søren; Rahbek, Anders

    We introduce the Qualitative Expectations Hypothesis (QEH) as a new approach to modeling macroeconomic and financial outcomes. Building on John Muth's seminal insight underpinning the Rational Expectations Hypothesis (REH), QEH represents the market's forecasts to be consistent with the predictions...... of an economist's model. However, by assuming that outcomes lie within stochastic intervals, QEH, unlike REH, recognizes the ambiguity faced by an economist and market participants alike. Moreover, QEH leaves the model open to ambiguity by not specifying a mechanism determining specific values that outcomes take...

  20. Revisiting the Dutch hypothesis

    NARCIS (Netherlands)

    Postma, Dirkje S.; Weiss, Scott T.; van den Berge, Maarten; Kerstjens, Huib A. M.; Koppelman, Gerard H.

    The Dutch hypothesis was first articulated in 1961, when many novel and advanced scientific techniques were not available, such as genomics techniques for pinpointing genes, gene expression, lipid and protein profiles, and the microbiome. In addition, computed tomographic scans and advanced analysis

  1. The Lehman Sisters Hypothesis

    NARCIS (Netherlands)

    I.P. van Staveren (Irene)

    2014-01-01

    markdownabstract__Abstract__ This article explores the Lehman Sisters Hypothesis. It reviews empirical literature about gender differences in behavioral, experimental, and neuro-economics as well as in other fields of behavioral research. It discusses gender differences along three dimensions of

  2. Hypothesis: does ochratoxin A cause testicular cancer?

    Science.gov (United States)

    Schwartz, Gary G

    2002-02-01

    Little is known about the etiology of testicular cancer, which is the most common cancer among young men. Epidemiologic data point to a carcinogenic exposure in early life or in utero, but the nature of the exposure is unknown. We hypothesize that the mycotoxin, ochratoxin A, is a cause of testicular cancer. Ochratoxin A is a naturally occurring contaminant of cereals, pigmeat, and other foods and is a known genotoxic carcinogen in animals. The major features of the descriptive epidemiology of testicular cancer (a high incidence in northern Europe, increasing incidence over time, and associations with high socioeconomic status, and with poor semen quality) are all associated with exposure to ochratoxin A. Exposure of animals to ochratoxin A via the diet or via in utero transfer induces adducts in testicular DNA. We hypothesize that consumption of foods contaminated with ochratoxin A during pregnancy and/or childhood induces lesions in testicular DNA and that puberty promotes these lesions to testicular cancer. We tested the ochratoxin A hypothesis using ecologic data on the per-capita consumption of cereals, coffee, and pigmeat, the principal dietary sources of ochratoxin A. Incidence rates for testicular cancer in 20 countries were significantly correlated with the per-capita consumption of coffee and pigmeat (r = 0.49 and 0.54, p = 0.03 and 0.01). The ochratoxin A hypothesis offers a coherent explanation for much of the descriptive epidemiology of testicular cancer and suggests new avenues for analytic research.

  3. Bayesian Hypothesis Testing

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, Stephen A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sigeti, David E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-15

    These are a set of slides about Bayesian hypothesis testing, where many hypotheses are tested. The conclusions are the following: The value of the Bayes factor obtained when using the median of the posterior marginal is almost the minimum value of the Bayes factor. The value of τ2 which minimizes the Bayes factor is a reasonable choice for this parameter. This allows a likelihood ratio to be computed with is the least favorable to H0.

  4. The Drift Burst Hypothesis

    OpenAIRE

    Christensen, Kim; Oomen, Roel; Renò, Roberto

    2016-01-01

    The Drift Burst Hypothesis postulates the existence of short-lived locally explosive trends in the price paths of financial assets. The recent US equity and Treasury flash crashes can be viewed as two high profile manifestations of such dynamics, but we argue that drift bursts of varying magnitude are an expected and regular occurrence in financial markets that can arise through established mechanisms such as feedback trading. At a theoretical level, we show how to build drift bursts into the...

  5. Hypothesis in research

    Directory of Open Access Journals (Sweden)

    Eudaldo Enrique Espinoza Freire

    2018-01-01

    Full Text Available It is intended with this work to have a material with the fundamental contents, which enable the university professor to formulate the hypothesis, for the development of an investigation, taking into account the problem to be solved. For its elaboration, the search of information in primary documents was carried out, such as thesis of degree and reports of research results, selected on the basis of its relevance with the analyzed subject, current and reliability, secondary documents, as scientific articles published in journals of recognized prestige, the selection was made with the same terms as in the previous documents. It presents a conceptualization of the updated hypothesis, its characterization and an analysis of the structure of the hypothesis in which the determination of the variables is deepened. The involvement of the university professor in the teaching-research process currently faces some difficulties, which are manifested, among other aspects, in an unstable balance between teaching and research, which leads to a separation between them.

  6. Nations within a nation: variations in epidemiological transition across the states of India, 1990-2016 in the Global Burden of Disease Study.

    Science.gov (United States)

    2017-12-02

    18% of the world's population lives in India, and many states of India have populations similar to those of large countries. Action to effectively improve population health in India requires availability of reliable and comprehensive state-level estimates of disease burden and risk factors over time. Such comprehensive estimates have not been available so far for all major diseases and risk factors. Thus, we aimed to estimate the disease burden and risk factors in every state of India as part of the Global Burden of Disease (GBD) Study 2016. Using all available data sources, the India State-Level Disease Burden Initiative estimated burden (metrics were deaths, disability-adjusted life-years [DALYs], prevalence, incidence, and life expectancy) from 333 disease conditions and injuries and 84 risk factors for each state of India from 1990 to 2016 as part of GBD 2016. We divided the states of India into four epidemiological transition level (ETL) groups on the basis of the ratio of DALYs from communicable, maternal, neonatal, and nutritional diseases (CMNNDs) to those from non-communicable diseases (NCDs) and injuries combined in 2016. We assessed variations in the burden of diseases and risk factors between ETL state groups and between states to inform a more specific health-system response in the states and for India as a whole. DALYs due to NCDs and injuries exceeded those due to CMNNDs in 2003 for India, but this transition had a range of 24 years for the four ETL state groups. The age-standardised DALY rate dropped by 36·2% in India from 1990 to 2016. The numbers of DALYs and DALY rates dropped substantially for most CMNNDs between 1990 and 2016 across all ETL groups, but rates of reduction for CMNNDs were slowest in the low ETL state group. By contrast, numbers of DALYs increased substantially for NCDs in all ETL state groups, and increased significantly for injuries in all ETL state groups except the highest. The all-age prevalence of most leading NCDs

  7. [Dilemma of null hypothesis in ecological hypothesis's experiment test.

    Science.gov (United States)

    Li, Ji

    2016-06-01

    Experimental test is one of the major test methods of ecological hypothesis, though there are many arguments due to null hypothesis. Quinn and Dunham (1983) analyzed the hypothesis deduction model from Platt (1964) and thus stated that there is no null hypothesis in ecology that can be strictly tested by experiments. Fisher's falsificationism and Neyman-Pearson (N-P)'s non-decisivity inhibit statistical null hypothesis from being strictly tested. Moreover, since the null hypothesis H 0 (α=1, β=0) and alternative hypothesis H 1 '(α'=1, β'=0) in ecological progresses are diffe-rent from classic physics, the ecological null hypothesis can neither be strictly tested experimentally. These dilemmas of null hypothesis could be relieved via the reduction of P value, careful selection of null hypothesis, non-centralization of non-null hypothesis, and two-tailed test. However, the statistical null hypothesis significance testing (NHST) should not to be equivalent to the causality logistical test in ecological hypothesis. Hence, the findings and conclusions about methodological studies and experimental tests based on NHST are not always logically reliable.

  8. The Bergschrund Hypothesis Revisited

    Science.gov (United States)

    Sanders, J. W.; Cuffey, K. M.; MacGregor, K. R.

    2009-12-01

    After Willard Johnson descended into the Lyell Glacier bergschrund nearly 140 years ago, he proposed that the presence of the bergschrund modulated daily air temperature fluctuations and enhanced freeze-thaw processes. He posited that glaciers, through their ability to birth bergschrunds, are thus able to induce rapid cirque headwall retreat. In subsequent years, many researchers challenged the bergschrund hypothesis on grounds that freeze-thaw events did not occur at depth in bergschrunds. We propose a modified version of Johnson’s original hypothesis: that bergschrunds maintain subfreezing temperatures at values that encourage rock fracture via ice lensing because they act as a cold air trap in areas that would otherwise be held near zero by temperate glacial ice. In support of this claim we investigated three sections of the bergschrund at the West Washmawapta Glacier, British Columbia, Canada, which sits in an east-facing cirque. During our bergschrund reconnaissance we installed temperature sensors at multiple elevations, light sensors at depth in 2 of the 3 locations and painted two 1 m2 sections of the headwall. We first emphasize bergschrunds are not wanting for ice: verglas covers significant fractions of the headwall and icicles dangle from the base of bödens or overhanging rocks. If temperature, rather than water availability, is the limiting factor governing ice-lensing rates, our temperature records demonstrate that the bergschrund provides a suitable environment for considerable rock fracture. At the three sites (north, west, and south walls), the average temperature at depth from 9/3/2006 to 8/6/2007 was -3.6, -3.6, and -2.0 °C, respectively. During spring, when we observed vast amounts of snow melt trickle in to the bergschrund, temperatures averaged -3.7, -3.8, and -2.2 °C, respectively. Winter temperatures are even lower: -8.5, -7.3, and -2.4 °C, respectively. Values during the following year were similar. During the fall, diurnal

  9. Surveillance and Epidemiology of Drug Resistant Infections Consortium (SEDRIC: Supporting the transition from strategy to action [version 1; referees: 2 approved, 1 approved with reservations

    Directory of Open Access Journals (Sweden)

    Keiji Fukuda

    2018-05-01

    Full Text Available In recognition of the central importance of surveillance and epidemiology in the control of antimicrobial resistance and the need to strengthen surveillance at all levels, Wellcome has brought together a new international expert group SEDRIC (Surveillance and Epidemiology of Drug Resistant Infections Consortium. SEDRIC aims to advance and transform the ways of tracking, sharing and analysing rates of infection and drug resistance, burden of disease, information on antibiotic use, opportunities for preventative measures such as vaccines, and contamination of the environment. SEDRIC will strengthen the availability of information needed to monitor and track risks, including an evaluation of access to, and utility of data generated by pharma and research activities, and will support the translation of surveillance data into interventions, changes in policy and more effective practices. Ways of working will include the provision of independent scientific analysis, advocacy and expert advice to groups, such as the Wellcome Drug Resistant Infection Priority Programme. A priority for SEDRIC’s first Working Group is to review mechanisms to strengthen the generation, collection, collation and dissemination of high quality data, together with the need for creativity in the use of existing data and proxy measures, and linking to existing in-country networking infrastructure. SEDRIC will also promote the translation of technological innovations into public health solutions.

  10. Epidemiological causality.

    Science.gov (United States)

    Morabia, Alfredo

    2005-01-01

    Epidemiological methods, which combine population thinking and group comparisons, can primarily identify causes of disease in populations. There is therefore a tension between our intuitive notion of a cause, which we want to be deterministic and invariant at the individual level, and the epidemiological notion of causes, which are invariant only at the population level. Epidemiologists have given heretofore a pragmatic solution to this tension. Causal inference in epidemiology consists in checking the logical coherence of a causality statement and determining whether what has been found grossly contradicts what we think we already know: how strong is the association? Is there a dose-response relationship? Does the cause precede the effect? Is the effect biologically plausible? Etc. This approach to causal inference can be traced back to the English philosophers David Hume and John Stuart Mill. On the other hand, the mode of establishing causality, devised by Jakob Henle and Robert Koch, which has been fruitful in bacteriology, requires that in every instance the effect invariably follows the cause (e.g., inoculation of Koch bacillus and tuberculosis). This is incompatible with epidemiological causality which has to deal with probabilistic effects (e.g., smoking and lung cancer), and is therefore invariant only for the population.

  11. Problems and prospects for maintaining the register of sanitary and epidemiological objects of surveillance for the tasks of the transition to risk-oriented model of activity

    Directory of Open Access Journals (Sweden)

    N.V. Zaitseva

    2015-03-01

    Full Text Available The article describes the approaches to the formation of regional databases of the objects of sanitary-epidemiological surveillance for the tasks of sequential evaluation of each object having the potential risk to the citizens of the affected areas of these objects, e.g. workers, consumers of products or services. The basic structure of the information system is demonstrated. The system is oriented to be used together with the DBMS MS Access. The system performs the manual quiding function for the register and implements the calculation algorithm of the health risk indicators and classification of the objects of surveillance. Approaches to the formation of the system have been tested in Perm, Lipetsk, Kaluga, Omsk regions as part of a pilot project of the Federal Service on Surveillance for Consumer rights protection and human well-being. The problems of the registers’ formation are in the fact of scares operational entering of the significant amount of information, that has been accumulated in Administration offices of Rospotrebnadzor, but do not exist in the form of electronic databases. The relevant issue is the development of guidance documents to ensure unified approaches to the registers’ formation and risk calculation in relation to population census under the influence of various activities.

  12. A hypothesis and a case-study projection of an influence of MJO modulation on boreal-summer tropical cyclogenesis in a warmer climate with a global non-hydrostatic model: a transition toward the central Pacific?

    Directory of Open Access Journals (Sweden)

    KAZUYOSHI eOOUCHI

    2014-02-01

    Full Text Available The eastward shift of the enhanced activity of tropical cyclone to the central Pacific is a robust projection result for a future warmer climate, and is shared by most of the state-of-the-art climate models. The shift has been argued to originate from the underlying El-Ñino like sea-surface temperature (SST forcing. This study explores the possibility that the change of the activity of the Madden-Julian Oscillation (MJO can be an additional, if not alternative, contributor to the shift, using the dataset of Yamada et al. (2010 from a global non-hydrostatic 14-km grid mesh time-slice experiment for a boreal-summer case. Within the case-study framework, we develop the hypothesis that an eastward shift of the high-activity area of the MJO, as manifested itself as the significant intra-seasonal modulation of the enhanced precipitation, is associated with the increased tropical cyclogenesis potential over the North central Pacific by regulating cyclonic relative vorticity and vertical shear. In contrast, the North Indian Ocean and maritime continent undergo relatively diminished genesis potential. An implication is that uncertainty in the future tropical cyclogenesis in some part of the Pacific and other ocean basins could be reduced if projection of the MJO and its connection with the underlying SST environment can be better understood and constrained by the improvement of climate models.

  13. Is the Aluminum Hypothesis Dead?

    Science.gov (United States)

    2014-01-01

    The Aluminum Hypothesis, the idea that aluminum exposure is involved in the etiology of Alzheimer disease, dates back to a 1965 demonstration that aluminum causes neurofibrillary tangles in the brains of rabbits. Initially the focus of intensive research, the Aluminum Hypothesis has gradually been abandoned by most researchers. Yet, despite this current indifference, the Aluminum Hypothesis continues to attract the attention of a small group of scientists and aluminum continues to be viewed with concern by some of the public. This review article discusses reasons that mainstream science has largely abandoned the Aluminum Hypothesis and explores a possible reason for some in the general public continuing to view aluminum with mistrust. PMID:24806729

  14. Alzheimer's disease: the amyloid hypothesis and the Inverse Warburg effect

    KAUST Repository

    Demetrius, Lloyd A.; Magistretti, Pierre J.; Pellerin, Luc

    2015-01-01

    Epidemiological and biochemical studies show that the sporadic forms of Alzheimer's disease (AD) are characterized by the following hallmarks: (a) An exponential increase with age; (b) Selective neuronal vulnerability; (c) Inverse cancer comorbidity. The present article appeals to these hallmarks to evaluate and contrast two competing models of AD: the amyloid hypothesis (a neuron-centric mechanism) and the Inverse Warburg hypothesis (a neuron-astrocytic mechanism). We show that these three hallmarks of AD conflict with the amyloid hypothesis, but are consistent with the Inverse Warburg hypothesis, a bioenergetic model which postulates that AD is the result of a cascade of three events—mitochondrial dysregulation, metabolic reprogramming (the Inverse Warburg effect), and natural selection. We also provide an explanation for the failures of the clinical trials based on amyloid immunization, and we propose a new class of therapeutic strategies consistent with the neuroenergetic selection model.

  15. Alzheimer's disease: the amyloid hypothesis and the Inverse Warburg effect

    KAUST Repository

    Demetrius, Lloyd A.

    2015-01-14

    Epidemiological and biochemical studies show that the sporadic forms of Alzheimer\\'s disease (AD) are characterized by the following hallmarks: (a) An exponential increase with age; (b) Selective neuronal vulnerability; (c) Inverse cancer comorbidity. The present article appeals to these hallmarks to evaluate and contrast two competing models of AD: the amyloid hypothesis (a neuron-centric mechanism) and the Inverse Warburg hypothesis (a neuron-astrocytic mechanism). We show that these three hallmarks of AD conflict with the amyloid hypothesis, but are consistent with the Inverse Warburg hypothesis, a bioenergetic model which postulates that AD is the result of a cascade of three events—mitochondrial dysregulation, metabolic reprogramming (the Inverse Warburg effect), and natural selection. We also provide an explanation for the failures of the clinical trials based on amyloid immunization, and we propose a new class of therapeutic strategies consistent with the neuroenergetic selection model.

  16. Eat dirt and avoid atopy: the hygiene hypothesis revisited.

    Science.gov (United States)

    Patki, Anil

    2007-01-01

    The explosive rise in the incidence of atopic diseases in the Western developed countries can be explained on the basis of the so-called "hygiene hypothesis". In short, it attributes the rising incidence of atopic dermatitis to reduced exposure to various childhood infections and bacterial endotoxins. Reduced exposure to dirt in the clean environment results in a skewed development of the immune system which results in an abnormal allergic response to various environmental allergens which are otherwise innocuous. This article reviews the historical aspects, epidemiological and immunological basis of the hygiene hypothesis and implications for Indian conditions.

  17. Epidemiologic evidence of health effects from long-distance transit of chemical weapons fallout from bombing early in the 1991 Persian Gulf War.

    Science.gov (United States)

    Haley, Robert W; Tuite, James J

    2013-01-01

    Military intelligence data published in a companion paper explain how chemical fallout from US and Coalition bombing of Iraqi chemical weapons facilities early in the air campaign transited long distance, triggering nerve agent alarms and exposing US troops. We report the findings of a population-based survey designed to test competing hypotheses on the impact on chronic Gulf War illness of nerve agent from early-war bombing versus post-war demolition. The US Military Health Survey performed computer-assisted telephone interviews of a stratified random sample of Gulf War-era veterans (n = 8,020). Early-war exposure was measured by having heard nerve agent alarms and post-war exposure, by the computer-generated plume from the Khamisiyah demolition. Gulf War illness was measured by two widely published case definitions. The OR (95% CI) for the association of alarms with the Factor case definition was 4.13 (95% CI 2.51-6.80) compared with 1.21 (95% CI 0.86-1.69) for the Khamisiyah plume. There was a dose-related trend for the number of alarms (p(trend) war demolition. Copyright © 2012 S. Karger AG, Basel.

  18. Epidemiology, hunger and development

    Directory of Open Access Journals (Sweden)

    Paulo H. Battaglin Machado

    2008-06-01

    Full Text Available Understanding the relationship between epidemiology and food security implies in disclosing famine causes, the way it is distributed in the society and to which extent it affects the populations. Building up from that perspective, this paper attempts to understand the famine logic throughout the various transitions accomplished in the past decades: epidemiologic, demographic, risk, nutritional and development. The reflexes of the demographic transition that took place in Brazil in the XXth century are related to the population nutritional status standard changes, that is, they shifted from malnutrition high prevalence to a significant increase in obesity. However, the paradox of this situation is due to the fact that most risk factors that bring about diseases of the modern world come from the “excess”, while millions die around the globe because of “deprivation”. The food production alone does not ensure its equitable distribution among the various groups of the society. The access alone does not lead to quality. The choices are made individually, but life style options imply in a set of correlations that go from economy to culture. It means that this field has a collective basis and encompasses environment and development.

  19. Hypothesis Designs for Three-Hypothesis Test Problems

    OpenAIRE

    Yan Li; Xiaolong Pu

    2010-01-01

    As a helpful guide for applications, the alternative hypotheses of the three-hypothesis test problems are designed under the required error probabilities and average sample number in this paper. The asymptotic formulas and the proposed numerical quadrature formulas are adopted, respectively, to obtain the hypothesis designs and the corresponding sequential test schemes under the Koopman-Darmois distributions. The example of the normal mean test shows that our methods are qu...

  20. Tests of the lunar hypothesis

    Science.gov (United States)

    Taylor, S. R.

    1984-01-01

    The concept that the Moon was fissioned from the Earth after core separation is the most readily testable hypothesis of lunar origin, since direct comparisons of lunar and terrestrial compositions can be made. Differences found in such comparisons introduce so many ad hoc adjustments to the fission hypothesis that it becomes untestable. Further constraints may be obtained from attempting to date the volatile-refractory element fractionation. The combination of chemical and isotopic problems suggests that the fission hypothesis is no longer viable, and separate terrestrial and lunar accretion from a population of fractionated precursor planetesimals provides a more reasonable explanation.

  1. Evaluating the Stage Learning Hypothesis.

    Science.gov (United States)

    Thomas, Hoben

    1980-01-01

    A procedure for evaluating the Genevan stage learning hypothesis is illustrated by analyzing Inhelder, Sinclair, and Bovet's guided learning experiments (in "Learning and the Development of Cognition." Cambridge: Harvard University Press, 1974). (Author/MP)

  2. The Purchasing Power Parity Hypothesis:

    African Journals Online (AJOL)

    2011-10-02

    Oct 2, 2011 ... reject the unit root hypothesis in real exchange rates may simply be due to the shortness ..... Violations of Purchasing Power Parity and Their Implications for Efficient ... Official Intervention in the Foreign Exchange Market:.

  3. Mathematical epidemiology

    CERN Document Server

    Driessche, Pauline; Wu, Jianhong

    2008-01-01

    Based on lecture notes of two summer schools with a mixed audience from mathematical sciences, epidemiology and public health, this volume offers a comprehensive introduction to basic ideas and techniques in modeling infectious diseases, for the comparison of strategies to plan for an anticipated epidemic or pandemic, and to deal with a disease outbreak in real time. It covers detailed case studies for diseases including pandemic influenza, West Nile virus, and childhood diseases. Models for other diseases including Severe Acute Respiratory Syndrome, fox rabies, and sexually transmitted infections are included as applications. Its chapters are coherent and complementary independent units. In order to accustom students to look at the current literature and to experience different perspectives, no attempt has been made to achieve united writing style or unified notation. Notes on some mathematical background (calculus, matrix algebra, differential equations, and probability) have been prepared and may be downlo...

  4. EPRI epidemiology

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    A fight is brewing within the electric power community over the fate of a proposed $5 to $8 million epidemiological study of the effects of radiation on US nuclear plant workers. Several industry experts, claiming the project would merely lead to confusion by producing no clear results, are trying to prevent the Electric Power Research Institute (EPRI) from funding what would be the largest ever occupational study of this kind, covering perhaps as many as 500,000 workers. Ralph Lapp, a well-known radiation physicist, says that EPRI is facing unprecedented technical dissent from within. He claims there is already plenty of evidence that nuclear utilities are among the safest places to work, at least in terms of cancer risk, and that the proposed EPRI study would raise new concerns without yielding any answers

  5. The atomic hypothesis: physical consequences

    International Nuclear Information System (INIS)

    Rivas, Martin

    2008-01-01

    The hypothesis that matter is made of some ultimate and indivisible objects, together with the restricted relativity principle, establishes a constraint on the kind of variables we are allowed to use for the variational description of elementary particles. We consider that the atomic hypothesis not only states the indivisibility of elementary particles, but also that these ultimate objects, if not annihilated, cannot be modified by any interaction so that all allowed states of an elementary particle are only kinematical modifications of any one of them. Therefore, an elementary particle cannot have excited states. In this way, the kinematical group of spacetime symmetries not only defines the symmetries of the system, but also the variables in terms of which the mathematical description of the elementary particles can be expressed in either the classical or the quantum mechanical description. When considering the interaction of two Dirac particles, the atomic hypothesis restricts the interaction Lagrangian to a kind of minimal coupling interaction

  6. Multiple sclerosis: a geographical hypothesis.

    Science.gov (United States)

    Carlyle, I P

    1997-12-01

    Multiple sclerosis remains a rare neurological disease of unknown aetiology, with a unique distribution, both geographically and historically. Rare in equatorial regions, it becomes increasingly common in higher latitudes; historically, it was first clinically recognized in the early nineteenth century. A hypothesis, based on geographical reasoning, is here proposed: that the disease is the result of a specific vitamin deficiency. Different individuals suffer the deficiency in separate and often unique ways. Evidence to support the hypothesis exists in cultural considerations, in the global distribution of the disease, and in its historical prevalence.

  7. Discussion of the Porter hypothesis

    International Nuclear Information System (INIS)

    1999-11-01

    In the reaction to the long-range vision of RMNO, published in 1996, The Dutch government posed the question whether a far-going and progressive modernization policy will lead to competitive advantages of high-quality products on partly new markets. Such a question is connected to the so-called Porter hypothesis: 'By stimulating innovation, strict environmental regulations can actually enhance competitiveness', from which statement it can be concluded that environment and economy can work together quite well. A literature study has been carried out in order to determine under which conditions that hypothesis is endorsed in the scientific literature and policy documents. Recommendations are given for further studies. refs

  8. The thrifty phenotype hypothesis revisited

    DEFF Research Database (Denmark)

    Vaag, A A; Grunnet, L G; Arora, G P

    2012-01-01

    Twenty years ago, Hales and Barker along with their co-workers published some of their pioneering papers proposing the 'thrifty phenotype hypothesis' in Diabetologia (4;35:595-601 and 3;36:62-67). Their postulate that fetal programming could represent an important player in the origin of type 2...... of the underlying molecular mechanisms. Type 2 diabetes is a multiple-organ disease, and developmental programming, with its idea of organ plasticity, is a plausible hypothesis for a common basis for the widespread organ dysfunctions in type 2 diabetes and the metabolic syndrome. Only two among the 45 known type 2...

  9. Coccidioidomycosis: epidemiology

    Directory of Open Access Journals (Sweden)

    Brown J

    2013-06-01

    Full Text Available Jennifer Brown,1 Kaitlin Benedict,2 Benjamin J Park,2 George R Thompson III1,31Department of Internal Medicine, Division of Infectious Diseases, University of California, Davis Medical Center, Sacramento, CA, USA; 2Mycotic Diseases Branch, Division of Foodborne, Waterborne, and Environmental Diseases, US Centers for Disease Control and Prevention, Atlanta, GA, USA; 3Department of Medical Microbiology and Immunology, One Shields Avenue, Tupper Hall, Coccidioidomycosis Serology Laboratory, University of California, Davis, CA, USAAbstract: Coccidioidomycosis consists of a spectrum of disease, ranging from a mild, self-limited, febrile illness to severe, life-threatening infection. It is caused by the soil-dwelling fungi, Coccidioides immitis and C. posadasii, which are present in diverse endemic areas. Climate changes and environmental factors affect the Coccidioides lifecycle and influence infection rates. The incidence of coccidioidomycosis has risen substantially over the past two decades. The vast majority of Coccidioides infections occur in the endemic zones, such as California, Arizona, Mexico, and Central America. Infections occurring outside those zones appear to be increasingly common, and pose unique clinical and public health challenges. It has long been known that elderly persons, pregnant women, and members of certain ethnic groups are at risk for severe or disseminated coccidioidomycosis. In recent years, it has become evident that persons with immunodeficiency diseases, diabetics, transplant recipients, and prisoners are also particularly vulnerable.Keywords: coccidioidomycosis, Coccidioides, epidemiology, incidence, risk factors, geography

  10. [Heart failure patterns in Djibouti: epidemiologic transition].

    Science.gov (United States)

    Massoure, P L; Roche, N C; Lamblin, G; Topin, F; Dehan, C; Kaiser, E; Fourcade, L

    2013-05-01

    The features of heart failure (HF) in Djibouti have not been well described. We sought to document the current patterns of HF here. We prospectively included Djiboutian adults hospitalized for HF in the French Military Hospital (Djibouti) from August 2008 through December 2010. Of 1688 adults hospitalized in the medical department, 45 (2.7%) had symptomatic HF: 38 (84%) men, mean age 55.8 years (range 27-75). Twenty-five (56%) patients were initially hospitalized for acute pulmonary edema. The underlying diseases included coronary artery disease (CAD) (62%), hypertensive heart disease (18%), rheumatic valvular disease (13%), and primary dilated cardiomyopathy (7%). Their cardiovascular risk factors included tobacco use (53%), hypertension (69%), diabetes (47%), and hypercholesterolemia (51%). Patients in the CAD group were older, and had diabetes more often (p<0.01). All khat chewers (53%) were males and smokers. Mean left ventricular ejection fraction (LVEF) was 39 ± 14%. During follow-up (14.4 ± 9 months), 8 (18%) patients died, 9 (20%) were again hospitalized for HF, and 3 (7%) had ischemic strokes. One month after discharge, the New York Heart Association (NYHA) class was II for 40%, III for 44%, and IV for 16%. Higher NYHA classes and dilated cardiomyopathy were both associated with poorer outcomes (p<0.03). In hospitalized Djiboutians, most HF patterns are similar to those in industrialized countries. CAD is more prevalent than previously reported in African patients with HF.

  11. [Eco-epidemiology: towards epidemiology of complexity].

    Science.gov (United States)

    Bizouarn, Philippe

    2016-05-01

    In order to solve public health problems posed by the epidemiology of risk factors centered on the individual and neglecting the causal processes linking the risk factors with the health outcomes, Mervyn Susser proposed a multilevel epidemiology called eco-epidemiology, addressing the interdependence of individuals and their connection with molecular, individual, societal, environmental levels of organization participating in the causal disease processes. The aim of this epidemiology is to integrate more than a level of organization in design, analysis and interpretation of health problems. After presenting the main criticisms of risk-factor epidemiology focused on the individual, we will try to show how eco-epidemiology and its development could help to understand the need for a broader and integrative epidemiology, in which studies designed to identify risk factors would be balanced by studies designed to answer other questions equally vital to public health. © 2016 médecine/sciences – Inserm.

  12. Clinical epidemiology.

    Science.gov (United States)

    Martin, S W; Bonnett, B

    1987-06-01

    Rational clinical practice requires deductive particularization of diagnostic findings, prognoses, and therapeutic responses from groups of animals (herds) to the individual animal (herd) under consideration This process utilizes concepts, skills, and methods of epidemiology, as they relate to the study of the distribution and determinants of health and disease in populations, and casts them in a clinical perspective.We briefly outline diagnostic strategies and introduce a measure of agreement, called kappa, between clinical diagnoses. This statistic is useful not only as a measure of diagnostic accuracy, but also as a means of quantifying and understanding disagreement between diagnosticians. It is disconcerting to many, clinicians included, that given a general deficit of data on sensitivity and specificity, the level of agreement between many clinical diagnoses is only moderate at best with kappa values of 0.3 to 0.6.Sensitivity, specificity, pretest odds, and posttest probability of disease are defined and related to the interpretation of clinical findings and ancillary diagnostic test results. An understanding of these features and how they relate to ruling-in or ruling-out a diagnosis, or minimizzing diagnostic errors will greatly enhance the diagnostic accuracy of the practitioner, and reduce the frequency of clinical disagreement. The approach of running multiple tests on every patient is not only wasteful and expensive, it is unlikely to improve the ability of the clinician to establish the correct diagnosis.We conclude with a discussion of how to decide on the best therapy, a discussion which centers on, and outlines the key features of, the well designed clinical trial. Like a diagnosis, the results from a clinical trial may not always be definitive, nonetheless it is the best available method of gleaning information about treatment efficacy.

  13. Salmonella epidemiology: A whirlwind of change.

    Science.gov (United States)

    Besser, John M

    2018-05-01

    The field of infectious disease epidemiology for Salmonella and other enteric pathogens is undergoing some of the most profound changes since the time of Kauffman and White. Rapid advances in "big data" technologies such as genomics and metagenomics are making it possible to monitor and control salmonellosis in new and exciting ways. Epidemiological methods are becoming increasingly robust through the routine use of standardized hypothesis-generating questionnaires, iterative open-ended interviewing, informational trace-backs and new modeling techniques for describing the attribution of disease to food sources. In addition, Salmonella epidemiology is facing important challenges and new opportunities due to the rapid adoption of culture independent diagnostic test panels by clinical laboratories. Where is this unprecedented wave of change taking us? This chapter will examine emerging trends in Salmonella epidemiology, and take a peek into the not-so-distant future. Published by Elsevier Ltd.

  14. Questioning the social intelligence hypothesis.

    Science.gov (United States)

    Holekamp, Kay E

    2007-02-01

    The social intelligence hypothesis posits that complex cognition and enlarged "executive brains" evolved in response to challenges that are associated with social complexity. This hypothesis has been well supported, but some recent data are inconsistent with its predictions. It is becoming increasingly clear that multiple selective agents, and non-selective constraints, must have acted to shape cognitive abilities in humans and other animals. The task now is to develop a larger theoretical framework that takes into account both inter-specific differences and similarities in cognition. This new framework should facilitate consideration of how selection pressures that are associated with sociality interact with those that are imposed by non-social forms of environmental complexity, and how both types of functional demands interact with phylogenetic and developmental constraints.

  15. Whiplash and the compensation hypothesis.

    Science.gov (United States)

    Spearing, Natalie M; Connelly, Luke B

    2011-12-01

    Review article. To explain why the evidence that compensation-related factors lead to worse health outcomes is not compelling, either in general, or in the specific case of whiplash. There is a common view that compensation-related factors lead to worse health outcomes ("the compensation hypothesis"), despite the presence of important, and unresolved sources of bias. The empirical evidence on this question has ramifications for the design of compensation schemes. Using studies on whiplash, this article outlines the methodological problems that impede attempts to confirm or refute the compensation hypothesis. Compensation studies are prone to measurement bias, reverse causation bias, and selection bias. Errors in measurement are largely due to the latent nature of whiplash injuries and health itself, a lack of clarity over the unit of measurement (specific factors, or "compensation"), and a lack of appreciation for the heterogeneous qualities of compensation-related factors and schemes. There has been a failure to acknowledge and empirically address reverse causation bias, or the likelihood that poor health influences the decision to pursue compensation: it is unclear if compensation is a cause or a consequence of poor health, or both. Finally, unresolved selection bias (and hence, confounding) is evident in longitudinal studies and natural experiments. In both cases, between-group differences have not been addressed convincingly. The nature of the relationship between compensation-related factors and health is unclear. Current approaches to testing the compensation hypothesis are prone to several important sources of bias, which compromise the validity of their results. Methods that explicitly test the hypothesis and establish whether or not a causal relationship exists between compensation factors and prolonged whiplash symptoms are needed in future studies.

  16. A Molecular–Structure Hypothesis

    Directory of Open Access Journals (Sweden)

    Jan C. A. Boeyens

    2010-11-01

    Full Text Available The self-similar symmetry that occurs between atomic nuclei, biological growth structures, the solar system, globular clusters and spiral galaxies suggests that a similar pattern should characterize atomic and molecular structures. This possibility is explored in terms of the current molecular structure-hypothesis and its extension into four-dimensional space-time. It is concluded that a quantum molecule only has structure in four dimensions and that classical (Newtonian structure, which occurs in three dimensions, cannot be simulated by quantum-chemical computation.

  17. Antiaging therapy: a prospective hypothesis

    Directory of Open Access Journals (Sweden)

    Shahidi Bonjar MR

    2015-01-01

    Full Text Available Mohammad Rashid Shahidi Bonjar,1 Leyla Shahidi Bonjar2 1School of Dentistry, Kerman University of Medical Sciences, Kerman Iran; 2Department of Pharmacology, College of Pharmacy, Kerman University of Medical Sciences, Kerman, Iran Abstract: This hypothesis proposes a new prospective approach to slow the aging process in older humans. The hypothesis could lead to developing new treatments for age-related illnesses and help humans to live longer. This hypothesis has no previous documentation in scientific media and has no protocol. Scientists have presented evidence that systemic aging is influenced by peculiar molecules in the blood. Researchers at Albert Einstein College of Medicine, New York, and Harvard University in Cambridge discovered elevated titer of aging-related molecules (ARMs in blood, which trigger cascade of aging process in mice; they also indicated that the process can be reduced or even reversed. By inhibiting the production of ARMs, they could reduce age-related cognitive and physical declines. The present hypothesis offers a new approach to translate these findings into medical treatment: extracorporeal adjustment of ARMs would lead to slower rates of aging. A prospective “antiaging blood filtration column” (AABFC is a nanotechnological device that would fulfill the central role in this approach. An AABFC would set a near-youth homeostatic titer of ARMs in the blood. In this regard, the AABFC immobilizes ARMs from the blood while blood passes through the column. The AABFC harbors antibodies against ARMs. ARM antibodies would be conjugated irreversibly to ARMs on contact surfaces of the reaction platforms inside the AABFC till near-youth homeostasis is attained. The treatment is performed with the aid of a blood-circulating pump. Similar to a renal dialysis machine, blood would circulate from the body to the AABFC and from there back to the body in a closed circuit until ARMs were sufficiently depleted from the blood. The

  18. Is PMI the Hypothesis or the Null Hypothesis?

    Science.gov (United States)

    Tarone, Aaron M; Sanford, Michelle R

    2017-09-01

    Over the past several decades, there have been several strident exchanges regarding whether forensic entomologists estimate the postmortem interval (PMI), minimum PMI, or something else. During that time, there has been a proliferation of terminology reflecting this concern regarding "what we do." This has been a frustrating conversation for some in the community because much of this debate appears to be centered on what assumptions are acknowledged directly and which are embedded within a list of assumptions (or ignored altogether) in the literature and in case reports. An additional component of the conversation centers on a concern that moving away from the use of certain terminology like PMI acknowledges limitations and problems that would make the application of entomology appear less useful in court-a problem for lawyers, but one that should not be problematic for scientists in the forensic entomology community, as uncertainty is part of science that should and can be presented effectively in the courtroom (e.g., population genetic concepts in forensics). Unfortunately, a consequence of the way this conversation is conducted is that even as all involved in the debate acknowledge the concerns of their colleagues, parties continue to talk past one another advocating their preferred terminology. Progress will not be made until the community recognizes that all of the terms under consideration take the form of null hypothesis statements and that thinking about "what we do" as a null hypothesis has useful legal and scientific ramifications that transcend arguments over the usage of preferred terminology. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. The Stoichiometric Divisome: A Hypothesis

    Directory of Open Access Journals (Sweden)

    Waldemar eVollmer

    2015-05-01

    Full Text Available Dividing Escherichia coli cells simultaneously constrict the inner membrane, peptidoglycan layer and outer membrane to synthesize the new poles of the daughter cells. For this, more than 30 proteins localize to mid-cell where they form a large, ring-like assembly, the divisome, facilitating division. Although the precise function of most divisome proteins is unknown, it became apparent in recent years that dynamic protein-protein interactions are essential for divisome assembly and function. However, little is known about the nature of the interactions involved and the stoichiometry of the proteins within the divisome. A recent study (Li et al., 2014 used ribosome profiling to measure the absolute protein synthesis rates in E. coli. Interestingly, they observed that most proteins which participate in known multiprotein complexes are synthesized proportional to their stoichiometry. Based on this principle we present a hypothesis for the stoichiometry of the core of the divisome, taking into account known protein-protein interactions. From this hypothesis we infer a possible mechanism for PG synthesis during division.

  20. Pinocchio: Geppetto's transitional object

    Directory of Open Access Journals (Sweden)

    Gabriele Zeloni

    2015-01-01

    Full Text Available The literature has been considered by Freud and others after him, a form of unaware exploration of mind that can leads to discoveries similar to psychoanalysis’s discoveries. From this perspective, the author puts forward the following hypothesis: Pinocchio is a puppet who comes to life and is therefore, from a child's perception, a transitional object according to Winnicott. Consequently Geppetto is nothing more than the involuntary representation of any child interacting with the transitional object. The author explains the results of the analysis of the text in support of the hypothesis and reflects on the impact of The adventure of Pinocchio on the reader.

  1. Epidemiology of IBD

    Science.gov (United States)

    ... IBD? Projects and Partners Data and Statistics Resources Epidemiology of the IBD Recommend on Facebook Tweet Share ... 5:1424-9. 2 Loftus EV, Jr. Clinical epidemiology of inflammatory bowel disease: Incidence, prevalence, and environmental ...

  2. International Lymphoma Epidemiology Consortium

    Science.gov (United States)

    The InterLymph Consortium, or formally the International Consortium of Investigators Working on Non-Hodgkin's Lymphoma Epidemiologic Studies, is an open scientific forum for epidemiologic research in non-Hodgkin's lymphoma.

  3. Evaluation of epidemiological studies

    International Nuclear Information System (INIS)

    Breckow, J.

    1995-01-01

    The publication is intended for readers with a professional background in radiation protection who are not experts in the field of epidemiology. The potentials and the limits of epidemiology are shown and concepts and terminology of radioepidemilogic studies as well as epidemiology in general are explained, in order to provide the necessary basis for understanding or performing evaluations of epidemiologic studies. (orig./VHE) [de

  4. Memory in astrocytes: a hypothesis

    Directory of Open Access Journals (Sweden)

    Caudle Robert M

    2006-01-01

    Full Text Available Abstract Background Recent work has indicated an increasingly complex role for astrocytes in the central nervous system. Astrocytes are now known to exchange information with neurons at synaptic junctions and to alter the information processing capabilities of the neurons. As an extension of this trend a hypothesis was proposed that astrocytes function to store information. To explore this idea the ion channels in biological membranes were compared to models known as cellular automata. These comparisons were made to test the hypothesis that ion channels in the membranes of astrocytes form a dynamic information storage device. Results Two dimensional cellular automata were found to behave similarly to ion channels in a membrane when they function at the boundary between order and chaos. The length of time information is stored in this class of cellular automata is exponentially related to the number of units. Therefore the length of time biological ion channels store information was plotted versus the estimated number of ion channels in the tissue. This analysis indicates that there is an exponential relationship between memory and the number of ion channels. Extrapolation of this relationship to the estimated number of ion channels in the astrocytes of a human brain indicates that memory can be stored in this system for an entire life span. Interestingly, this information is not affixed to any physical structure, but is stored as an organization of the activity of the ion channels. Further analysis of two dimensional cellular automata also demonstrates that these systems have both associative and temporal memory capabilities. Conclusion It is concluded that astrocytes may serve as a dynamic information sink for neurons. The memory in the astrocytes is stored by organizing the activity of ion channels and is not associated with a physical location such as a synapse. In order for this form of memory to be of significant duration it is necessary

  5. Genesis of Preeclampsia: An Epidemiological Approach

    Science.gov (United States)

    Salvador-Moysén, Jaime; Martínez-López, Yolanda; Ramírez-Aranda, José M.; Aguilar-Durán, Marisela; Terrones-González, Alberto

    2012-01-01

    There are analyzed some of the main aspects related to the causality of preeclampsia, privileging two types of models: the clinic model and the epidemiologic model, first one represented by the hypothesis of the reduced placental perfusion and the second one considering the epidemiologic findings related to the high levels of psychosocial stress and its association with preeclampsia. It is reasoned out the relevance of raising the causality of the disease from an interdisciplinary perspective, integrating the valuable information generated from both types, clinical and epidemiologic, and finally a tentative explanatory model of preeclampsia is proposed, the subclinical and sociocultural aspects that predispose and trigger the disease are emphasized making aspects to stand out: the importance of reduced placental perfusion as an indicator of individual risk, and the high levels of physiological stress, as a result of the unfavorable conditions of the psychosocial surroundings (indicator of population risk) of the pregnant women. PMID:22462008

  6. Robust and distributed hypothesis testing

    CERN Document Server

    Gül, Gökhan

    2017-01-01

    This book generalizes and extends the available theory in robust and decentralized hypothesis testing. In particular, it presents a robust test for modeling errors which is independent from the assumptions that a sufficiently large number of samples is available, and that the distance is the KL-divergence. Here, the distance can be chosen from a much general model, which includes the KL-divergence as a very special case. This is then extended by various means. A minimax robust test that is robust against both outliers as well as modeling errors is presented. Minimax robustness properties of the given tests are also explicitly proven for fixed sample size and sequential probability ratio tests. The theory of robust detection is extended to robust estimation and the theory of robust distributed detection is extended to classes of distributions, which are not necessarily stochastically bounded. It is shown that the quantization functions for the decision rules can also be chosen as non-monotone. Finally, the boo...

  7. The venom optimization hypothesis revisited.

    Science.gov (United States)

    Morgenstern, David; King, Glenn F

    2013-03-01

    Animal venoms are complex chemical mixtures that typically contain hundreds of proteins and non-proteinaceous compounds, resulting in a potent weapon for prey immobilization and predator deterrence. However, because venoms are protein-rich, they come with a high metabolic price tag. The metabolic cost of venom is sufficiently high to result in secondary loss of venom whenever its use becomes non-essential to survival of the animal. The high metabolic cost of venom leads to the prediction that venomous animals may have evolved strategies for minimizing venom expenditure. Indeed, various behaviors have been identified that appear consistent with frugality of venom use. This has led to formulation of the "venom optimization hypothesis" (Wigger et al. (2002) Toxicon 40, 749-752), also known as "venom metering", which postulates that venom is metabolically expensive and therefore used frugally through behavioral control. Here, we review the available data concerning economy of venom use by animals with either ancient or more recently evolved venom systems. We conclude that the convergent nature of the evidence in multiple taxa strongly suggests the existence of evolutionary pressures favoring frugal use of venom. However, there remains an unresolved dichotomy between this economy of venom use and the lavish biochemical complexity of venom, which includes a high degree of functional redundancy. We discuss the evidence for biochemical optimization of venom as a means of resolving this conundrum. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Alien abduction: a medical hypothesis.

    Science.gov (United States)

    Forrest, David V

    2008-01-01

    In response to a new psychological study of persons who believe they have been abducted by space aliens that found that sleep paralysis, a history of being hypnotized, and preoccupation with the paranormal and extraterrestrial were predisposing experiences, I noted that many of the frequently reported particulars of the abduction experience bear more than a passing resemblance to medical-surgical procedures and propose that experience with these may also be contributory. There is the altered state of consciousness, uniformly colored figures with prominent eyes, in a high-tech room under a round bright saucerlike object; there is nakedness, pain and a loss of control while the body's boundaries are being probed; and yet the figures are thought benevolent. No medical-surgical history was apparently taken in the above mentioned study, but psychological laboratory work evaluated false memory formation. I discuss problems in assessing intraoperative awareness and ways in which the medical hypothesis could be elaborated and tested. If physicians are causing this syndrome in a percentage of patients, we should know about it; and persons who feel they have been abducted should be encouraged to inform their surgeons and anesthesiologists without challenging their beliefs.

  9. The oxidative hypothesis of senescence

    Directory of Open Access Journals (Sweden)

    Gilca M

    2007-01-01

    Full Text Available The oxidative hypothesis of senescence, since its origin in 1956, has garnered significant evidence and growing support among scientists for the notion that free radicals play an important role in ageing, either as "damaging" molecules or as signaling molecules. Age-increasing oxidative injuries induced by free radicals, higher susceptibility to oxidative stress in short-lived organisms, genetic manipulations that alter both oxidative resistance and longevity and the anti-ageing effect of caloric restriction and intermittent fasting are a few examples of accepted scientific facts that support the oxidative theory of senescence. Though not completely understood due to the complex "network" of redox regulatory systems, the implication of oxidative stress in the ageing process is now well documented. Moreover, it is compatible with other current ageing theories (e.g., those implicating the mitochondrial damage/mitochondrial-lysosomal axis, stress-induced premature senescence, biological "garbage" accumulation, etc. This review is intended to summarize and critically discuss the redox mechanisms involved during the ageing process: sources of oxidant agents in ageing (mitochondrial -electron transport chain, nitric oxide synthase reaction- and non-mitochondrial- Fenton reaction, microsomal cytochrome P450 enzymes, peroxisomal β -oxidation and respiratory burst of phagocytic cells, antioxidant changes in ageing (enzymatic- superoxide dismutase, glutathione-reductase, glutathion peroxidase, catalase- and non-enzymatic glutathione, ascorbate, urate, bilirubine, melatonin, tocopherols, carotenoids, ubiquinol, alteration of oxidative damage repairing mechanisms and the role of free radicals as signaling molecules in ageing.

  10. Global, regional, and national disability-adjusted life years (DALYs) for 306 diseases and injuries and healthy life expectancy (HALE) for 188 countries, 1990-2013 : quantifying the epidemiological transition

    NARCIS (Netherlands)

    Murray, Christopher J. L.; Barber, Ryan M.; Foreman, Kyle J.; Ozgoren, Ayse Abbasoglu; Abd-Allah, Foad; Abera, Semaw F.; Aboyans, Victor; Abraham, Jerry P.; Abubakar, Ibrahim; Abu-Raddad, Laith J.; Abu-Rmeileh, Niveen M.; Achoki, Tom; Ackerman, Ilana N.; Ademi, Zanfina; Adou, Arsene K.; Adsuar, Jose C.; Afshin, Ashkan; Agardh, Emilie E.; Alam, Sayed Saidul; Alasfoor, Deena; Albittar, Mohammed I.; Alegretti, Miguel A.; Alemu, Zewdie A.; Alfonso-Cristancho, Rafael; Alhabib, Samia; Ali, Raghib; Alla, Francois; Allebeck, Peter; Almazroa, Mohammad A.; Alsharif, Ubai; Alvarez, Elena; Alvis-Guzman, Nelson; Amare, Azmeraw T.; Ameh, Emmanuel A.; Amini, Heresh; Ammar, Walid; Anderson, H. Ross; Anderson, Benjamin O.; Antonio, Carl Abelardo T.; Anwari, Palwasha; Arnlov, Johan; Arsenijevic, Valentina S. Arsic; Artaman, Al; Asghar, Rana J.; Assadi, Reza; Atkins, Lydia S.; Avila, Marco A.; Awuah, Baffour; Hoek, Hans W.; Singh, Abhishek

    2015-01-01

    Background The Global Burden of Disease Study 2013 (GBD 2013) aims to bring together all available epidemiological data using a coherent measurement framework, standardised estimation methods, and transparent data sources to enable comparisons of health loss over time and across causes, age-sex

  11. Global, regional, and national disability-adjusted life years (DALYs) for 306 diseases and injuries and healthy life expectancy (HALE) for 188 countries, 1990–2013: quantifying the epidemiological transition

    NARCIS (Netherlands)

    Murray, C.J.; Barber, R.M.; Foreman, K.J.; Geleijnse, J.M.

    2015-01-01

    Background The Global Burden of Disease Study 2013 (GBD 2013) aims to bring together all available epidemiological data using a coherent measurement framework, standardised estimation methods, and transparent data sources to enable comparisons of health loss over time and across causes, age–sex

  12. The Carnivore Connection Hypothesis: Revisited

    Directory of Open Access Journals (Sweden)

    Jennie C. Brand-Miller

    2012-01-01

    Full Text Available The “Carnivore Connection” hypothesizes that, during human evolution, a scarcity of dietary carbohydrate in diets with low plant : animal subsistence ratios led to insulin resistance providing a survival and reproductive advantage with selection of genes for insulin resistance. The selection pressure was relaxed at the beginning of the Agricultural Revolution when large quantities of cereals first entered human diets. The “Carnivore Connection” explains the high prevalence of intrinsic insulin resistance and type 2 diabetes in populations that transition rapidly from traditional diets with a low-glycemic load, to high-carbohydrate, high-glycemic index diets that characterize modern diets. Selection pressure has been relaxed longest in European populations, explaining a lower prevalence of insulin resistance and type 2 diabetes, despite recent exposure to famine and food scarcity. Increasing obesity and habitual consumption of high-glycemic-load diets worsens insulin resistance and increases the risk of type 2 diabetes in all populations.

  13. Eigenstate Phase Transitions

    Science.gov (United States)

    Zhao, Bo

    Phase transitions are one of the most exciting physical phenomena ever discovered. The understanding of phase transitions has long been of interest. Recently eigenstate phase transitions have been discovered and studied; they are drastically different from traditional thermal phase transitions. In eigenstate phase transitions, a sharp change is exhibited in properties of the many-body eigenstates of the Hamiltonian of a quantum system, but not the thermal equilibrium properties of the same system. In this thesis, we study two different types of eigenstate phase transitions. The first is the eigenstate phase transition within the ferromagnetic phase of an infinite-range spin model. By studying the interplay of the eigenstate thermalization hypothesis and Ising symmetry breaking, we find two eigenstate phase transitions within the ferromagnetic phase: In the lowest-temperature phase the magnetization can macroscopically oscillate by quantum tunneling between up and down. The relaxation of the magnetization is always overdamped in the remainder of the ferromagnetic phase, which is further divided into phases where the system thermally activates itself over the barrier between the up and down states, and where it quantum tunnels. The second is the many-body localization phase transition. The eigenstates on one side of the transition obey the eigenstate thermalization hypothesis; the eigenstates on the other side are many-body localized, and thus thermal equilibrium need not be achieved for an initial state even after evolving for an arbitrary long time. We study this many-body localization phase transition in the strong disorder renormalization group framework. After setting up a set of coarse-graining rules for a general one dimensional chain, we get a simple "toy model'' and obtain an almost purely analytical solution to the infinite-randomness critical fixed point renormalization group equation. We also get an estimate of the correlation length critical exponent nu

  14. Epidemiological studies in mucus hypersecretion

    DEFF Research Database (Denmark)

    Vestbo, Jørgen

    2002-01-01

    Respiratory mucus in epidemiology has mainly been studied using standardized questionnaires including questions on cough and phlegm. In chronic obstructive pulmonary disease (COPD) much controversy exists regarding the importance of mucus hypersecretion. From being the key element in the 'British...... hypothesis' it was reduced to being an innocent disorder in the 1980s but is now again recognized as a potential risk factor for an accelerated loss of lung function. Whereas early studies in mainly occupational cohorts showed no effect of chronic mucus hypersecretion on decline in lung function......, such an effect has been shown in subsequent studies on general population samples. Chronic mucus hypersecretion also increases risk of hospital admission which may be due to an increased risk of lower respiratory tract infection. In severe COPD this may explain the increased mortality associated...

  15. Low dose epidemiology

    International Nuclear Information System (INIS)

    Tirmarche, M.; Hubert, P.

    1992-01-01

    Actually, epidemiological studies have to establish if the assessment of cancer risk can be verified at low chronic radiation doses. The population surveillance must be very long, the side effects and cancers of such radiation appearing much later. In France, this epidemiological study on nuclear workers have been decided recently. Before describing the experiment and french projects in epidemiology of nuclear workers, the authors present the main english and american studies

  16. Updating the mild encephalitis hypothesis of schizophrenia.

    Science.gov (United States)

    Bechter, K

    2013-04-05

    Schizophrenia seems to be a heterogeneous disorder. Emerging evidence indicates that low level neuroinflammation (LLNI) may not occur infrequently. Many infectious agents with low overall pathogenicity are risk factors for psychoses including schizophrenia and for autoimmune disorders. According to the mild encephalitis (ME) hypothesis, LLNI represents the core pathogenetic mechanism in a schizophrenia subgroup that has syndromal overlap with other psychiatric disorders. ME may be triggered by infections, autoimmunity, toxicity, or trauma. A 'late hit' and gene-environment interaction are required to explain major findings about schizophrenia, and both aspects would be consistent with the ME hypothesis. Schizophrenia risk genes stay rather constant within populations despite a resulting low number of progeny; this may result from advantages associated with risk genes, e.g., an improved immune response, which may act protectively within changing environments, although they are associated with the disadvantage of increased susceptibility to psychotic disorders. Specific schizophrenic symptoms may arise with instances of LLNI when certain brain functional systems are involved, in addition to being shaped by pre-existing liability factors. Prodrome phase and the transition to a diseased status may be related to LLNI processes emerging and varying over time. The variability in the course of schizophrenia resembles the varying courses of autoimmune disorders, which result from three required factors: genes, the environment, and the immune system. Preliminary criteria for subgrouping neurodevelopmental, genetic, ME, and other types of schizophrenias are provided. A rare example of ME schizophrenia may be observed in Borna disease virus infection. Neurodevelopmental schizophrenia due to early infections has been estimated by others to explain approximately 30% of cases, but the underlying pathomechanisms of transition to disease remain in question. LLNI (e.g. from

  17. Validity of Linder Hypothesis in Bric Countries

    Directory of Open Access Journals (Sweden)

    Rana Atabay

    2016-03-01

    Full Text Available In this study, the theory of similarity in preferences (Linder hypothesis has been introduced and trade in BRIC countries has been examined whether the trade between these countries was valid for this hypothesis. Using the data for the period 1996 – 2010, the study applies to panel data analysis in order to provide evidence regarding the empirical validity of the Linder hypothesis for BRIC countries’ international trade. Empirical findings show that the trade between BRIC countries is in support of Linder hypothesis.

  18. The contribution of epidemiology

    NARCIS (Netherlands)

    Brandt, P. van den; Voorrips, L.; Hertz-Picciotto, I.; Shuker, D.; Boeing, H.; Speijers, G.; Guittard, C.; Kleiner, J.; Knowles, M.; Wolk, A.; Goldbohm, A.

    2002-01-01

    Epidemiologic studies directly contribute data on risk (or benefit) in humans as the investigated species, and in the full food intake range normally encountered by humans. This paper starts with introducing the epidemiologic approach, followed by a discussion of perceived differences between

  19. Inflammation and the Two-Hit Hypothesis of Schizophrenia

    Science.gov (United States)

    Feigenson, Keith A.; Kusnecov, Alex W.; Silverstein, Steven M.

    2014-01-01

    The high societal and individual cost of schizophrenia necessitates finding better, more effective treatment, diagnosis, and prevention strategies. One of the obstacles in this endeavor is the diverse set of etiologies that comprises schizophrenia. A substantial body of evidence has grown over the last few decades to suggest that schizophrenia is a heterogeneous syndrome with overlapping symptoms and etiologies. At the same time, an increasing number of clinical, epidemiological, and experimental studies have shown links between schizophrenia and inflammatory conditions. In this review, we analyze the literature on inflammation and schizophrenia, with a particular focus on comorbidity, biomarkers, and environmental insults. We then identify several mechanisms by which inflammation could influence the development of schizophrenia via the two-hit hypothesis. Lastly, we note the relevance of these findings to clinical applications in the diagnosis, prevention, and treatment of schizophrenia. PMID:24247023

  20. Hypothesis Testing in the Real World

    Science.gov (United States)

    Miller, Jeff

    2017-01-01

    Critics of null hypothesis significance testing suggest that (a) its basic logic is invalid and (b) it addresses a question that is of no interest. In contrast to (a), I argue that the underlying logic of hypothesis testing is actually extremely straightforward and compelling. To substantiate that, I present examples showing that hypothesis…

  1. Error probabilities in default Bayesian hypothesis testing

    NARCIS (Netherlands)

    Gu, Xin; Hoijtink, Herbert; Mulder, J,

    2016-01-01

    This paper investigates the classical type I and type II error probabilities of default Bayes factors for a Bayesian t test. Default Bayes factors quantify the relative evidence between the null hypothesis and the unrestricted alternative hypothesis without needing to specify prior distributions for

  2. Reassessing the Trade-off Hypothesis

    DEFF Research Database (Denmark)

    Rosas, Guillermo; Manzetti, Luigi

    2015-01-01

    Do economic conditions drive voters to punish politicians that tolerate corruption? Previous scholarly work contends that citizens in young democracies support corrupt governments that are capable of promoting good economic outcomes, the so-called trade-off hypothesis. We test this hypothesis based...

  3. Mastery Learning and the Decreasing Variability Hypothesis.

    Science.gov (United States)

    Livingston, Jennifer A.; Gentile, J. Ronald

    1996-01-01

    This report results from studies that tested two variations of Bloom's decreasing variability hypothesis using performance on successive units of achievement in four graduate classrooms that used mastery learning procedures. Data do not support the decreasing variability hypothesis; rather, they show no change over time. (SM)

  4. Convergence of the epidemiology and pathology of COPD

    DEFF Research Database (Denmark)

    Vestbo, Jørgen; Hogg, J C

    2006-01-01

    The epidemiology of chronic obstructive pulmonary disease (COPD) has been dominated by one hypothesis stating that cigarette smoking and chronic bronchitis were the key to pathogenesis and another that asthma, chronic bronchitis, and even emphysema are related to different expressions of a primary...

  5. WHO - IPHECA: Epidemiological aspects

    International Nuclear Information System (INIS)

    Souchkevitch, G.

    1996-01-01

    In May 1991 the World Health Assembly endorsed the establishment of the International Programme on the Health Effects of the Chernobyl Accident (IPHECA) under the auspices of WHO. Five pilot projects have been carried out within IPHECA in the study territories of Belarus, Russian Federation and Ukraine in a period from 1991 to 1994. This pilot projects dealt with the detection and treatment of leukaemia and related diseases (Haematology Project), thyroid disorders (Thyroid project), brain damage during exposure 'in-utero' (Brain Damage 'in-Utero' project) and with the development of the Chernobyl registries (Epidemiological Registry Project). A fifth pilot project on oral health was performed only in Belarus. Epidemiological investigations have been an important component of all IPHECA pilot projects. Within 'Epidemiological Registry' Project such investigations have been the principal activity. But with respect to other IPHECA projects it was carried out in addition to main objectives relating to medical monitoring, early diagnosis and treatment of specific diseases included in project protocols. To support the epidemiological investigations within IPHECA, WHO supplied 41 computers in Belarus, Russian Federation and Ukraine and provided training for specialists from these countries in internationally recognized centres. The training programmes and host countries were as follows: standardization of epidemiological investigations (United Kingdom), radiation epidemiology (Russia), development of software (United Kingdom), principles of epidemiological investigations (The Czech Republic), cohort investigations (Japan)

  6. WHO - IPHECA: Epidemiological aspects

    Energy Technology Data Exchange (ETDEWEB)

    Souchkevitch, G [World Health Organization, Geneva (Swaziland)

    1996-07-01

    In May 1991 the World Health Assembly endorsed the establishment of the International Programme on the Health Effects of the Chernobyl Accident (IPHECA) under the auspices of WHO. Five pilot projects have been carried out within IPHECA in the study territories of Belarus, Russian Federation and Ukraine in a period from 1991 to 1994. This pilot projects dealt with the detection and treatment of leukaemia and related diseases (Haematology Project), thyroid disorders (Thyroid project), brain damage during exposure 'in-utero' (Brain Damage 'in-Utero' project) and with the development of the Chernobyl registries (Epidemiological Registry Project). A fifth pilot project on oral health was performed only in Belarus. Epidemiological investigations have been an important component of all IPHECA pilot projects. Within 'Epidemiological Registry' Project such investigations have been the principal activity. But with respect to other IPHECA projects it was carried out in addition to main objectives relating to medical monitoring, early diagnosis and treatment of specific diseases included in project protocols. To support the epidemiological investigations within IPHECA, WHO supplied 41 computers in Belarus, Russian Federation and Ukraine and provided training for specialists from these countries in internationally recognized centres. The training programmes and host countries were as follows: standardization of epidemiological investigations (United Kingdom), radiation epidemiology (Russia), development of software (United Kingdom), principles of epidemiological investigations (The Czech Republic), cohort investigations (Japan)

  7. Basic concepts of epidemiology

    International Nuclear Information System (INIS)

    Savitz, D.A.

    1984-01-01

    Epidemiology can be defined simply as the science of the distribution and determinants of disease in human populations. As a descriptive tool, epidemiology can aid health care service providers, for example, in allocation of resources. In its analytic capacity, the epidemiologic approach can help identify determinants of disease through the study of human populations. Epidemiology is primarily an observational rather than experimental methodology, with corresponding strengths and limitations. Relative to other approaches for assessing disease etiology and impacts of potential health hazards, epidemiology has a rather unique role that is complementary to, but independent of, both basic biologic sciences and clinical medicine. Experimental biologic sciences such as toxicology and physiology provide critical information on biologic mechanisms of disease required for causal inference. Clinical medicine often serves as the warning system that provides etiologic clues to be pursued through systematic investigation. The advantage of the epidemiologic approach is its reliance on human field experience, that is, the real world. While laboratory experimentation is uniquely well suited to defining potential hazards, it can neither determine whether human populations have actually been affected nor quantify that effect. Building all the complexities of human behavior and external factors into a laboratory study or mathematical model is impossible. By studying the world as it exists, epidemiology examines the integrated, summarized product of the myriad factors influencing health

  8. Epidemiology: Then and Now.

    Science.gov (United States)

    Kuller, Lewis H

    2016-03-01

    Twenty-five years ago, on the 75th anniversary of the Johns Hopkins Bloomberg School of Public Health, I noted that epidemiologic research was moving away from the traditional approaches used to investigate "epidemics" and their close relationship with preventive medicine. Twenty-five years later, the role of epidemiology as an important contribution to human population research, preventive medicine, and public health is under substantial pressure because of the emphasis on "big data," phenomenology, and personalized medical therapies. Epidemiology is the study of epidemics. The primary role of epidemiology is to identify the epidemics and parameters of interest of host, agent, and environment and to generate and test hypotheses in search of causal pathways. Almost all diseases have a specific distribution in relation to time, place, and person and specific "causes" with high effect sizes. Epidemiology then uses such information to develop interventions and test (through clinical trials and natural experiments) their efficacy and effectiveness. Epidemiology is dependent on new technologies to evaluate improved measurements of host (genomics), epigenetics, identification of agents (metabolomics, proteomics), new technology to evaluate both physical and social environment, and modern methods of data collection. Epidemiology does poorly in studying anything other than epidemics and collections of numerators and denominators without specific hypotheses even with improved statistical methodologies. © The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Epidemiology and Radiation Protection

    International Nuclear Information System (INIS)

    1987-01-01

    Epidemiology aims at providing direct evidence of the long term health effects in humans due to potentially dangerous exposures to various nuisance agents, including ionising radiation. Inappropriate interpretation and use of the results of epidemiological studies may result in inaccurate assessments of the risks associated with radiation exposure. This report presents the proceedings of a Workshop organised by the NEA to create an opportunity for epidemiologists and radiation protection specialists to exchange their experiences and views on the problems of methodology in epidemiological research and on the application of its results to the assessment of radiation risks

  10. A hypothesis to explain childhood cancers near nuclear power plants

    International Nuclear Information System (INIS)

    Fairlie, Ian

    2014-01-01

    Over 60 epidemiological studies world-wide have examined cancer incidences in children near nuclear power plants (NPPs): most of them indicate leukemia increases. These include the 2008 KiKK study commissioned by the German Government which found relative risks (RR) of 1.6 in total cancers and 2.2 in leukemias among infants living within 5 km of all German NPPs. The KiKK study has retriggered the debate as to the cause(s) of these increased cancers. A suggested hypothesis is that the increased cancers arise from radiation exposures to pregnant women near NPPs. However any theory has to account for the >10,000 fold discrepancy between official dose estimates from NPP emissions and observed increased risks. An explanation may be that doses from spikes in NPP radionuclide emissions are significantly larger than those estimated by official models which are diluted through the use of annual averages. In addition, risks to embryos/fetuses are greater than those to adults and haematopoietic tissues appear more radiosensitive in embryos/fetuses than in newborn babies. The product of possible increased doses and possible increased risks per dose may provide an explanation. - Highlights: • Over 60 studies worldwide on increased cancers near nuclear power plants (NPPs). • German government KiKK study provides very strong evidence. • Hypothesis proposes cancers arise in pregnant women near NPPs. • Nuclide spikes during refuelling could result in increased exposures. • Explanation offered for discrepancy between small dose estimates and large risks

  11. More than genes: the advanced fetal programming hypothesis.

    Science.gov (United States)

    Hocher, Berthold

    2014-10-01

    Many lines of data, initial epidemiologic studies as well as subsequent extensive experimental studies, indicate that early-life events play a powerful role in influencing later suceptibility to certain chronic diseases. Such events might be over- or undernutrition, exposure to environmental toxins, but also changes in hormones, in particular stress hormones. Typically, those events are triggered by the environmental challenges of the mother. However, recent studies have shown that paternal environmental or nutritional factors affect the phenotype of the offspring as well. The maternal and paternal environmental factors act on the phenotype of the offspring via epigenetic modification of its genome. The advanced fetal programming hypothesis proposes an additional non-environmentally driven mechanism: maternal and also paternal genes may influence the maturating sperm, the oocyte, and later the embryo/fetus, leading to their epigenetic alteration. Thus, the observed phenotype of the offspring may be altered by maternal/paternal genes independent of the fetal genome. Meanwhile, several independent association studies in humans dealing with metabolic and neurological traits also suggest that maternal genes might affect the offspring phenotype independent of the transmission of that particular gene to the offspring. Considering the implications of this hypothesis, some conclusions drawn from transgenic or knockout animal models and based on the causality between a genetic alteration and a phenotype, need to be challenged. Possible implications for the development, diagnostic and therapy of human genetic diseases have to be investigated. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  12. Epidemiology and risk assessment for radiation

    International Nuclear Information System (INIS)

    Badwe, R.A.

    2014-01-01

    The hazard and exposures from radiation are known with reasonable accuracy. However, at 'low levels' uncertainty persists as to whether the dose response relationship is linear and whether there is a dose threshold, below which there is no risk. Some have proposed that 'low' exposures to radiation may be beneficial, a hypothesis referred to as 'hormesis'. Over recent decades, various expert groups have adopted linear no-threshold dose-response models for radiation and cancer, based on review of epidemiological and biological evidence. The unexpected epidemic of thyroid cancer among children following the Chernobyl disaster was noticed. The research with epidemiological data and knowledge of the radionuclides to which the children were exposed is needed. Currently a debate concerning potential risks of high frequency electromagnetic radiation from mobile phones illustrates another need for further research

  13. Cancer Epidemiology Cohorts

    Science.gov (United States)

    Cohort studies are fundamental for epidemiological research by helping researchers better understand the etiology of cancer and provide insights into the key determinants of this disease and its outcomes.

  14. Epidemiology & Genomics Research Program

    Science.gov (United States)

    The Epidemiology and Genomics Research Program, in the National Cancer Institute's Division of Cancer Control and Population Sciences, funds research in human populations to understand the determinants of cancer occurrence and outcomes.

  15. Transit value capture coordination : case studies, best practices, and recommendations.

    Science.gov (United States)

    2015-02-17

    This study is based on the hypothesis that coordination between transit capital planners, municipal taxation authorities, and private developers and stakeholders can be a benefit to transit capital projects that choose to use value capture as a fundi...

  16. Beyond the hypothesis: Theory's role in the genesis, opposition, and pursuit of the Higgs boson

    Science.gov (United States)

    Wells, James D.

    2018-05-01

    The centrally recognized theoretical achievement that enabled the Higgs boson discovery in 2012 was the hypothesis of its existence, made by Peter Higgs in 1964. Nevertheless, there is a significant body of comparably important theoretical work prior to and after the Higgs boson hypothesis. In this article we present an additional perspective of how crucial theory work was to the genesis of the Higgs boson hypothesis, especially emphasizing its roots in Landau's theory of phase transitions and subsequent theoretical work on superconductivity. A detailed description is then given of the opposition to the Higgs boson hypothesis by many researchers, giving evidence to its speculative nature. And finally, it is discussed the importance of theory work in the decades after the hypothesis in order to make possible the experimental discovery of the Higgs boson.

  17. Implications of the Bohm-Aharonov hypothesis

    International Nuclear Information System (INIS)

    Ghirardi, G.C.; Rimini, A.; Weber, T.

    1976-01-01

    It is proved that the Bohm-Aharonov hypothesis concerning largerly separated subsystems of composite quantum systems implies that it is impossible to express the dynamical evolution in terms of the density operator

  18. Multi-agent sequential hypothesis testing

    KAUST Repository

    Kim, Kwang-Ki K.; Shamma, Jeff S.

    2014-01-01

    incorporate costs of taking private/public measurements, costs of time-difference and disagreement in actions of agents, and costs of false declaration/choices in the sequential hypothesis testing. The corresponding sequential decision processes have well

  19. Methodologic frontiers in environmental epidemiology.

    OpenAIRE

    Rothman, K J

    1993-01-01

    Environmental epidemiology comprises the epidemiologic study of those environmental factors that are outside the immediate control of the individual. Exposures of interest to environmental epidemiologists include air pollution, water pollution, occupational exposure to physical and chemical agents, as well as psychosocial elements of environmental concern. The main methodologic problem in environmental epidemiology is exposure assessment, a problem that extends through all of epidemiologic re...

  20. The (not so) Immortal Strand Hypothesis

    OpenAIRE

    Tomasetti, Cristian; Bozic, Ivana

    2015-01-01

    Background: Non-random segregation of DNA strands during stem cell replication has been proposed as a mechanism to minimize accumulated genetic errors in stem cells of rapidly dividing tissues. According to this hypothesis, an “immortal” DNA strand is passed to the stem cell daughter and not the more differentiated cell, keeping the stem cell lineage replication error-free. After it was introduced, experimental evidence both in favor and against the hypothesis has been presented. Principal...

  1. A reformulation of the hygiene hypothesis

    DEFF Research Database (Denmark)

    Hersoug, Lars-Georg

    2006-01-01

    Epidemiological studies have shown an inverse relationship between allergic respiratory diseases and the number of siblings. It was hypothesized that the lower prevalence of allergic respiratory diseases in large sibships was due to cross-infections between siblings. According to this hygiene...

  2. Epidemiology and costs of diabetes.

    Science.gov (United States)

    Bruno, G; Landi, A

    2011-01-01

    The prevalence of diabetes is increasing worldwide, particularly in developing countries. In the next decades, India and China are expected to provide the greatest numbers of affected people, mainly owing to the increasing incidence of this disease in those countries. Regarding developed countries, such as in Europe and the United States, the increasing trend is mainly due to the prolonged survival of both the general and the diabetic populations. From an epidemiologic point of view, the first relevant point is that almost 80% of diabetes cases could be prevented just by avoiding overweight and obesity. The estimated attributable risk of excess body weight is extremely high; no other modifiable effect has such an impact on the health of the general population. The second relevant point is that the global trend of the disease shows a tendency to onset at a younger age. The third point is that in developed countries the prevalence of diabetes is increasing mainly among the elderly, who are responsible for the highest consumption of health care resources in absolute terms. Regarding type 1 diabetes, which represents one-tenth of affected individuals, both large geographic and temporal variations in disease incidence have been found, supporting the hypothesis of as yet unknown environmental determinants. The incidence is increasing in linear fashion, not supporting the hypothesis of younger age at onset as the main explanation for this trend. Because the prevalences of both type 1 and type 2 diabetes are increasing worldwide, they will produce a profound impact on overall health care costs. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Multiple hypothesis tracking for the cyber domain

    Science.gov (United States)

    Schwoegler, Stefan; Blackman, Sam; Holsopple, Jared; Hirsch, Michael J.

    2011-09-01

    This paper discusses how methods used for conventional multiple hypothesis tracking (MHT) can be extended to domain-agnostic tracking of entities from non-kinematic constraints such as those imposed by cyber attacks in a potentially dense false alarm background. MHT is widely recognized as the premier method to avoid corrupting tracks with spurious data in the kinematic domain but it has not been extensively applied to other problem domains. The traditional approach is to tightly couple track maintenance (prediction, gating, filtering, probabilistic pruning, and target confirmation) with hypothesis management (clustering, incompatibility maintenance, hypothesis formation, and Nassociation pruning). However, by separating the domain specific track maintenance portion from the domain agnostic hypothesis management piece, we can begin to apply the wealth of knowledge gained from ground and air tracking solutions to the cyber (and other) domains. These realizations led to the creation of Raytheon's Multiple Hypothesis Extensible Tracking Architecture (MHETA). In this paper, we showcase MHETA for the cyber domain, plugging in a well established method, CUBRC's INFormation Engine for Real-time Decision making, (INFERD), for the association portion of the MHT. The result is a CyberMHT. We demonstrate the power of MHETA-INFERD using simulated data. Using metrics from both the tracking and cyber domains, we show that while no tracker is perfect, by applying MHETA-INFERD, advanced nonkinematic tracks can be captured in an automated way, perform better than non-MHT approaches, and decrease analyst response time to cyber threats.

  4. Aminoglycoside antibiotics and autism: a speculative hypothesis

    Directory of Open Access Journals (Sweden)

    Manev Hari

    2001-10-01

    Full Text Available Abstract Background Recently, it has been suspected that there is a relationship between therapy with some antibiotics and the onset of autism; but even more curious, some children benefited transiently from a subsequent treatment with a different antibiotic. Here, we speculate how aminoglycoside antibiotics might be associated with autism. Presentation We hypothesize that aminoglycoside antibiotics could a trigger the autism syndrome in susceptible infants by causing the stop codon readthrough, i.e., a misreading of the genetic code of a hypothetical critical gene, and/or b improve autism symptoms by correcting the premature stop codon mutation in a hypothetical polymorphic gene linked to autism. Testing Investigate, retrospectively, whether a link exists between aminoglycoside use (which is not extensive in children and the onset of autism symptoms (hypothesis "a", or between amino glycoside use and improvement of these symptoms (hypothesis "b". Whereas a prospective study to test hypothesis "a" is not ethically justifiable, a study could be designed to test hypothesis "b". Implications It should be stressed that at this stage no direct evidence supports our speculative hypothesis and that its main purpose is to initiate development of new ideas that, eventually, would improve our understanding of the pathobiology of autism.

  5. Against Popperized epidemiology.

    Science.gov (United States)

    Jacobsen, M

    1976-03-01

    The recommendation of Popper's philosophy of science should be adopted by epidemiologists is disputed. Reference is made to other authors who have shown that the most constructive elements in Popper's ideas have been advocated by earlier philosophers and have been used in epidemiology without abandoning inductive reasoning. It is argued that Popper's denigration of inductive methods is particularly harmful to epidemiology. Inductive reasoning and statistical inference play a key role in the science; it is suggested that unfamiliarity with these ideas contributes to widespread misunderstanding of the function of epidemiology. Attention is drawn to a common fallacy involving correlations between three random variables. The prevalence of the fallacy may be related to confusion between deductive and inductive logic.

  6. Ophthalmic epidemiology in Europe

    DEFF Research Database (Denmark)

    Delcourt, Cécile; Korobelnik, Jean-François; Buitendijk, Gabriëlle H S

    2016-01-01

    The European Eye Epidemiology (E3) consortium is a recently formed consortium of 29 groups from 12 European countries. It already comprises 21 population-based studies and 20 other studies (case-control, cases only, randomized trials), providing ophthalmological data on approximately 170,000 Euro......The European Eye Epidemiology (E3) consortium is a recently formed consortium of 29 groups from 12 European countries. It already comprises 21 population-based studies and 20 other studies (case-control, cases only, randomized trials), providing ophthalmological data on approximately 170......,000 European participants. The aim of the consortium is to promote and sustain collaboration and sharing of data and knowledge in the field of ophthalmic epidemiology in Europe, with particular focus on the harmonization of methods for future research, estimation and projection of frequency and impact...

  7. Testing competing forms of the Milankovitch hypothesis

    DEFF Research Database (Denmark)

    Kaufmann, Robert K.; Juselius, Katarina

    2016-01-01

    We test competing forms of the Milankovitch hypothesis by estimating the coefficients and diagnostic statistics for a cointegrated vector autoregressive model that includes 10 climate variables and four exogenous variables for solar insolation. The estimates are consistent with the physical...... ice volume and solar insolation. The estimated adjustment dynamics show that solar insolation affects an array of climate variables other than ice volume, each at a unique rate. This implies that previous efforts to test the strong form of the Milankovitch hypothesis by examining the relationship...... that the latter is consistent with a weak form of the Milankovitch hypothesis and that it should be restated as follows: Internal climate dynamics impose perturbations on glacial cycles that are driven by solar insolation. Our results show that these perturbations are likely caused by slow adjustment between land...

  8. Rejecting the equilibrium-point hypothesis.

    Science.gov (United States)

    Gottlieb, G L

    1998-01-01

    The lambda version of the equilibrium-point (EP) hypothesis as developed by Feldman and colleagues has been widely used and cited with insufficient critical understanding. This article offers a small antidote to that lack. First, the hypothesis implicitly, unrealistically assumes identical transformations of lambda into muscle tension for antagonist muscles. Without that assumption, its definitions of command variables R, C, and lambda are incompatible and an EP is not defined exclusively by R nor is it unaffected by C. Second, the model assumes unrealistic and unphysiological parameters for the damping properties of the muscles and reflexes. Finally, the theory lacks rules for two of its three command variables. A theory of movement should offer insight into why we make movements the way we do and why we activate muscles in particular patterns. The EP hypothesis offers no unique ideas that are helpful in addressing either of these questions.

  9. The linear hypothesis and radiation carcinogenesis

    International Nuclear Information System (INIS)

    Roberts, P.B.

    1981-10-01

    An assumption central to most estimations of the carcinogenic potential of low levels of ionising radiation is that the risk always increases in direct proportion to the dose received. This assumption (the linear hypothesis) has been both strongly defended and attacked on several counts. It appears unlikely that conclusive, direct evidence on the validity of the hypothesis will be forthcoming. We review the major indirect arguments used in the debate. All of them are subject to objections that can seriously weaken their case. In the present situation, retention of the linear hypothesis as the basis of extrapolations from high to low dose levels can lead to excessive fears, over-regulation and unnecessarily expensive protection measures. To offset these possibilities, support is given to suggestions urging a cut-off dose, probably some fraction of natural background, below which risks can be deemed acceptable

  10. Rayleigh's hypothesis and the geometrical optics limit.

    Science.gov (United States)

    Elfouhaily, Tanos; Hahn, Thomas

    2006-09-22

    The Rayleigh hypothesis (RH) is often invoked in the theoretical and numerical treatment of rough surface scattering in order to decouple the analytical form of the scattered field. The hypothesis stipulates that the scattered field away from the surface can be extended down onto the rough surface even though it is formed by solely up-going waves. Traditionally this hypothesis is systematically used to derive the Volterra series under the small perturbation method which is equivalent to the low-frequency limit. In this Letter we demonstrate that the RH also carries the high-frequency or the geometrical optics limit, at least to first order. This finding has never been explicitly derived in the literature. Our result comforts the idea that the RH might be an exact solution under some constraints in the general case of random rough surfaces and not only in the case of small-slope deterministic periodic gratings.

  11. Transitional Justice

    DEFF Research Database (Denmark)

    Gissel, Line Engbo

    This presentation builds on an earlier published article, 'Contemporary Transitional Justice: Normalising a Politics of Exception'. It argues that the field of transitional justice has undergone a shift in conceptualisation and hence practice. Transitional justice is presently understood to be th...... to be the provision of ordinary criminal justice in contexts of exceptional political transition.......This presentation builds on an earlier published article, 'Contemporary Transitional Justice: Normalising a Politics of Exception'. It argues that the field of transitional justice has undergone a shift in conceptualisation and hence practice. Transitional justice is presently understood...

  12. Nuclear accidents and epidemiology

    International Nuclear Information System (INIS)

    1987-01-01

    A consultation on epidemiology related to the Chernobyl accident was held in Copenhagen in May 1987 as a basis for concerted action. This was followed by a joint IAEA/WHO workshop in Vienna, which reviewed appropriate methodologies for possible long-term effects of radiation following nuclear accidents. The reports of these two meetings are included in this volume, and cover the subjects: 1) Epidemiology related to the Chernobyl nuclear accident. 2) Appropriate methodologies for studying possible long-term effects of radiation on individuals exposed in a nuclear accident. Figs and tabs

  13. Advances in radiation epidemiology

    International Nuclear Information System (INIS)

    Boice, J.

    1997-01-01

    The 1994 UNSCEAR report provides an informative review of radiation epidemiology. During the past 2 years there have been several major advances in our understanding of radiation effects based on new studies of atomic bomb survivors in Japan, of patients given diagnostic and therapeutic radiation (including iodine-131), of workers occupationally exposed, and of general populations exposed to residential radon. Laboratory approaches are also being incorporated into epidemiological investigations to learn more about the biological mechanism by which radiation causes cancer in man. (author)

  14. Global transition i sundhed

    DEFF Research Database (Denmark)

    Bygbjerg, Ib Christian; Meyrowitsch, Dan W

    2006-01-01

    , and by degenerative, and man-made diseases in ageing populations. Omran could not foresee the HIV/AIDS pandemic or the dramatic fall in longevity and fertility in, for example, Russia. But his model remains of value for health planners and politicians. We advocate for research in the interplay between diseases......Global epidemiological transition reflected in changed patterns of death and diseases was first described by Omran; decreasing death and disease rates from infectious diseases, particularly in children and the young, are followed by decreased fertility rate and increased longevity...

  15. On the generalized gravi-magnetic hypothesis

    International Nuclear Information System (INIS)

    Massa, C.

    1989-01-01

    According to a generalization of the gravi-magnetic hypothesis (GMH) any neutral mass moving in a curvilinear path with respect to an inertial frame creates a magnetic field, dependent on the curvature radius of the path. A simple astrophysical consequence of the generalized GMH is suggested considering the special cases of binary pulsars and binary neutron stars

  16. Remarks about the hypothesis of limiting fragmentation

    International Nuclear Information System (INIS)

    Chou, T.T.; Yang, C.N.

    1987-01-01

    Remarks are made about the hypothesis of limiting fragmentation. In particular, the concept of favored and disfavored fragment distribution is introduced. Also, a sum rule is proved leading to a useful quantity called energy-fragmentation fraction. (author). 11 refs, 1 fig., 2 tabs

  17. Multiple hypothesis clustering in radar plot extraction

    NARCIS (Netherlands)

    Huizing, A.G.; Theil, A.; Dorp, Ph. van; Ligthart, L.P.

    1995-01-01

    False plots and plots with inaccurate range and Doppler estimates may severely degrade the performance of tracking algorithms in radar systems. This paper describes how a multiple hypothesis clustering technique can be applied to mitigate the problems involved in plot extraction. The measures of

  18. The (not so immortal strand hypothesis

    Directory of Open Access Journals (Sweden)

    Cristian Tomasetti

    2015-03-01

    Significance: Utilizing an approach that is fundamentally different from previous efforts to confirm or refute the immortal strand hypothesis, we provide evidence against non-random segregation of DNA during stem cell replication. Our results strongly suggest that parental DNA is passed randomly to stem cell daughters and provides new insight into the mechanism of DNA replication in stem cells.

  19. A Developmental Study of the Infrahumanization Hypothesis

    Science.gov (United States)

    Martin, John; Bennett, Mark; Murray, Wayne S.

    2008-01-01

    Intergroup attitudes in children were examined based on Leyen's "infrahumanization hypothesis". This suggests that some uniquely human emotions, such as shame and guilt (secondary emotions), are reserved for the in-group, whilst other emotions that are not uniquely human and shared with animals, such as anger and pleasure (primary…

  20. Morbidity and Infant Development: A Hypothesis.

    Science.gov (United States)

    Pollitt, Ernesto

    1983-01-01

    Results of a study conducted in 14 villages of Sui Lin Township, Taiwan, suggest the hypothesis that, under conditions of extreme economic impoverishment and among children within populations where energy protein malnutrition is endemic, there is an inverse relationship between incidence of morbidity in infancy and measures of motor and mental…

  1. Diagnostic Hypothesis Generation and Human Judgment

    Science.gov (United States)

    Thomas, Rick P.; Dougherty, Michael R.; Sprenger, Amber M.; Harbison, J. Isaiah

    2008-01-01

    Diagnostic hypothesis-generation processes are ubiquitous in human reasoning. For example, clinicians generate disease hypotheses to explain symptoms and help guide treatment, auditors generate hypotheses for identifying sources of accounting errors, and laypeople generate hypotheses to explain patterns of information (i.e., data) in the…

  2. Multi-hypothesis distributed stereo video coding

    DEFF Research Database (Denmark)

    Salmistraro, Matteo; Zamarin, Marco; Forchhammer, Søren

    2013-01-01

    for stereo sequences, exploiting an interpolated intra-view SI and two inter-view SIs. The quality of the SI has a major impact on the DVC Rate-Distortion (RD) performance. As the inter-view SIs individually present lower RD performance compared with the intra-view SI, we propose multi-hypothesis decoding...

  3. [Resonance hypothesis of heart rate variability origin].

    Science.gov (United States)

    Sheĭkh-Zade, Iu R; Mukhambetaliev, G Kh; Cherednik, I L

    2009-09-01

    A hypothesis is advanced of the heart rate variability being subjected to beat-to-beat regulation of cardiac cycle duration in order to ensure the resonance interaction between respiratory and own fluctuation of the arterial system volume for minimization of power expenses of cardiorespiratory system. Myogenic, parasympathetic and sympathetic machanisms of heart rate variability are described.

  4. In Defense of Chi's Ontological Incompatibility Hypothesis

    Science.gov (United States)

    Slotta, James D.

    2011-01-01

    This article responds to an article by A. Gupta, D. Hammer, and E. F. Redish (2010) that asserts that M. T. H. Chi's (1992, 2005) hypothesis of an "ontological commitment" in conceptual development is fundamentally flawed. In this article, I argue that Chi's theoretical perspective is still very much intact and that the critique offered by Gupta…

  5. Vacuum counterexamples to the cosmic censorship hypothesis

    International Nuclear Information System (INIS)

    Miller, B.D.

    1981-01-01

    In cylindrically symmetric vacuum spacetimes it is possible to specify nonsingular initial conditions such that timelike singularities will (necessarily) evolve from these conditions. Examples are given; the spacetimes are somewhat analogous to one of the spherically symmetric counterexamples to the cosmic censorship hypothesis

  6. Epidemiology of burns

    NARCIS (Netherlands)

    Dokter, Jan

    2016-01-01

    The aim of this thesis is to understand the epidemiology, treatment and outcomes of specialized burn care in The Netherlands. This thesis is mainly based on historical data of the burn centre in Rotterdam from 1986, combined with historical data from the burn centres in Groningen and Beverwijk from

  7. Translational Epidemiology in Psychiatry

    Science.gov (United States)

    Weissman, Myrna M.; Brown, Alan S.; Talati, Ardesheer

    2012-01-01

    Translational research generally refers to the application of knowledge generated by advances in basic sciences research translated into new approaches for diagnosis, prevention, and treatment of disease. This direction is called bench-to-bedside. Psychiatry has similarly emphasized the basic sciences as the starting point of translational research. This article introduces the term translational epidemiology for psychiatry research as a bidirectional concept in which the knowledge generated from the bedside or the population can also be translated to the benches of laboratory science. Epidemiologic studies are primarily observational but can generate representative samples, novel designs, and hypotheses that can be translated into more tractable experimental approaches in the clinical and basic sciences. This bedside-to-bench concept has not been explicated in psychiatry, although there are an increasing number of examples in the research literature. This article describes selected epidemiologic designs, providing examples and opportunities for translational research from community surveys and prospective, birth cohort, and family-based designs. Rapid developments in informatics, emphases on large sample collection for genetic and biomarker studies, and interest in personalized medicine—which requires information on relative and absolute risk factors—make this topic timely. The approach described has implications for providing fresh metaphors to communicate complex issues in interdisciplinary collaborations and for training in epidemiology and other sciences in psychiatry. PMID:21646577

  8. The Epidemiology of Pheochromocytoma

    DEFF Research Database (Denmark)

    Ladefoged Ebbehøj, Andreas

    2017-01-01

    Pheochromocytoma and catecholamine secreting paraganglioma (PPGL) are exceedingly rare endocrine tumours, but remain a frequent diagnostic dilemma due to their potential life-threatening nature. Reliable data on the epidemiology of PPGL is lacking and no time trends in incidence rates (IR) have...

  9. A novel hypothesis splitting method implementation for multi-hypothesis filters

    DEFF Research Database (Denmark)

    Bayramoglu, Enis; Ravn, Ole; Andersen, Nils Axel

    2013-01-01

    The paper presents a multi-hypothesis filter library featuring a novel method for splitting Gaussians into ones with smaller variances. The library is written in C++ for high performance and the source code is open and free1. The multi-hypothesis filters commonly approximate the distribution tran...

  10. The Income Inequality Hypothesis Revisited : Assessing the Hypothesis Using Four Methodological Approaches

    NARCIS (Netherlands)

    Kragten, N.; Rözer, J.

    The income inequality hypothesis states that income inequality has a negative effect on individual’s health, partially because it reduces social trust. This article aims to critically assess the income inequality hypothesis by comparing several analytical strategies, namely OLS regression,

  11. Einstein's Revolutionary Light-Quantum Hypothesis

    Science.gov (United States)

    Stuewer, Roger H.

    2005-05-01

    The paper in which Albert Einstein proposed his light-quantum hypothesis was the only one of his great papers of 1905 that he himself termed ``revolutionary.'' Contrary to widespread belief, Einstein did not propose his light-quantum hypothesis ``to explain the photoelectric effect.'' Instead, he based his argument for light quanta on the statistical interpretation of the second law of thermodynamics, with the photoelectric effect being only one of three phenomena that he offered as possible experimental support for it. I will discuss Einstein's light-quantum hypothesis of 1905 and his introduction of the wave-particle duality in 1909 and then turn to the reception of his work on light quanta by his contemporaries. We will examine the reasons that prominent physicists advanced to reject Einstein's light-quantum hypothesis in succeeding years. Those physicists included Robert A. Millikan, even though he provided convincing experimental proof of the validity of Einstein's equation of the photoelectric effect in 1915. The turning point came after Arthur Holly Compton discovered the Compton effect in late 1922, but even then Compton's discovery was contested both on experimental and on theoretical grounds. Niels Bohr, in particular, had never accepted the reality of light quanta and now, in 1924, proposed a theory, the Bohr-Kramers-Slater theory, which assumed that energy and momentum were conserved only statistically in microscopic interactions. Only after that theory was disproved experimentally in 1925 was Einstein's revolutionary light-quantum hypothesis generally accepted by physicists---a full two decades after Einstein had proposed it.

  12. A Dopamine Hypothesis of Autism Spectrum Disorder.

    Science.gov (United States)

    Pavăl, Denis

    2017-01-01

    Autism spectrum disorder (ASD) comprises a group of neurodevelopmental disorders characterized by social deficits and stereotyped behaviors. While several theories have emerged, the pathogenesis of ASD remains unknown. Although studies report dopamine signaling abnormalities in autistic patients, a coherent dopamine hypothesis which could link neurobiology to behavior in ASD is currently lacking. In this paper, we present such a hypothesis by proposing that autistic behavior arises from dysfunctions in the midbrain dopaminergic system. We hypothesize that a dysfunction of the mesocorticolimbic circuit leads to social deficits, while a dysfunction of the nigrostriatal circuit leads to stereotyped behaviors. Furthermore, we discuss 2 key predictions of our hypothesis, with emphasis on clinical and therapeutic aspects. First, we argue that dopaminergic dysfunctions in the same circuits should associate with autistic-like behavior in nonautistic subjects. Concerning this, we discuss the case of PANDAS (pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections) which displays behaviors similar to those of ASD, presumed to arise from dopaminergic dysfunctions. Second, we argue that providing dopamine modulators to autistic subjects should lead to a behavioral improvement. Regarding this, we present clinical studies of dopamine antagonists which seem to have improving effects on autistic behavior. Furthermore, we explore the means of testing our hypothesis by using neuroreceptor imaging, which could provide comprehensive evidence for dopamine signaling dysfunctions in autistic subjects. Lastly, we discuss the limitations of our hypothesis. Along these lines, we aim to provide a dopaminergic model of ASD which might lead to a better understanding of the ASD pathogenesis. © 2017 S. Karger AG, Basel.

  13. Perspective: Structural fluctuation of protein and Anfinsen's thermodynamic hypothesis

    Science.gov (United States)

    Hirata, Fumio; Sugita, Masatake; Yoshida, Masasuke; Akasaka, Kazuyuki

    2018-01-01

    The thermodynamics hypothesis, casually referred to as "Anfinsen's dogma," is described theoretically in terms of a concept of the structural fluctuation of protein or the first moment (average structure) and the second moment (variance and covariance) of the structural distribution. The new theoretical concept views the unfolding and refolding processes of protein as a shift of the structural distribution induced by a thermodynamic perturbation, with the variance-covariance matrix varying. Based on the theoretical concept, a method to characterize the mechanism of folding (or unfolding) is proposed. The transition state, if any, between two stable states is interpreted as a gap in the distribution, which is created due to an extensive reorganization of hydrogen bonds among back-bone atoms of protein and with water molecules in the course of conformational change. Further perspective to applying the theory to the computer-aided drug design, and to the material science, is briefly discussed.

  14. Implications of infectious diseases and the adrenal hypothesis for the etiology of childhood acute lymphoblastic leukemia

    Directory of Open Access Journals (Sweden)

    F. Azevedo-Silva

    2010-03-01

    Full Text Available Acute leukemia is the most frequent cancer in children. Recently, a new hypothesis was proposed for the pathogenesis of childhood acute lymphoblastic leukemia (ALL. The so-called "adrenal hypothesis" emphasized the role of endogenous cortisol in the etiology of B-cell precursor ALL. The incidence peak of ALL in children between 3 to 5 years of age has been well documented and is consistent with this view. The adrenal hypothesis proposes that the risk of childhood B-cell precursor ALL is reduced when early childhood infections induce qualitative and quantitative changes in the hypothalamus-pituitary-adrenal axis. It suggests that the increased plasma cortisol levels would be sufficient to eliminate all clonal leukemic cells originating during fetal life. Because Brazil is a continental and tropical country, the exposure to infections is diversified with endemic viral and regionally non-viral infections, with some characteristics that support the recent adrenal hypothesis. Here we discuss this new hypothesis in terms of data from epidemiological studies and the possible implications of the diversity of infections occurring in Brazilian children.

  15. Tests of the Giant Impact Hypothesis

    Science.gov (United States)

    Jones, J. H.

    1998-01-01

    The giant impact hypothesis has gained popularity as a means of explaining a volatile-depleted Moon that still has a chemical affinity to the Earth. As Taylor's Axiom decrees, the best models of lunar origin are testable, but this is difficult with the giant impact model. The energy associated with the impact would be sufficient to totally melt and partially vaporize the Earth. And this means that there should he no geological vestige of Barber times. Accordingly, it is important to devise tests that may be used to evaluate the giant impact hypothesis. Three such tests are discussed here. None of these is supportive of the giant impact model, but neither do they disprove it.

  16. The discovered preference hypothesis - an empirical test

    DEFF Research Database (Denmark)

    Lundhede, Thomas; Ladenburg, Jacob; Olsen, Søren Bøye

    Using stated preference methods for valuation of non-market goods is known to be vulnerable to a range of biases. Some authors claim that these so-called anomalies in effect render the methods useless for the purpose. However, the Discovered Preference Hypothesis, as put forth by Plott [31], offers...... an nterpretation and explanation of biases which entails that the stated preference methods need not to be completely written off. In this paper we conduct a test for the validity and relevance of the DPH interpretation of biases. In a choice experiment concerning preferences for protection of Danish nature areas...... as respondents evaluate more and more choice sets. This finding supports the Discovered Preference Hypothesis interpretation and explanation of starting point bias....

  17. The Hypothesis-Driven Physical Examination.

    Science.gov (United States)

    Garibaldi, Brian T; Olson, Andrew P J

    2018-05-01

    The physical examination remains a vital part of the clinical encounter. However, physical examination skills have declined in recent years, in part because of decreased time at the bedside. Many clinicians question the relevance of physical examinations in the age of technology. A hypothesis-driven approach to teaching and practicing the physical examination emphasizes the performance of maneuvers that can alter the likelihood of disease. Likelihood ratios are diagnostic weights that allow clinicians to estimate the post-probability of disease. This hypothesis-driven approach to the physical examination increases its value and efficiency, while preserving its cultural role in the patient-physician relationship. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. MOLIERE: Automatic Biomedical Hypothesis Generation System.

    Science.gov (United States)

    Sybrandt, Justin; Shtutman, Michael; Safro, Ilya

    2017-08-01

    Hypothesis generation is becoming a crucial time-saving technique which allows biomedical researchers to quickly discover implicit connections between important concepts. Typically, these systems operate on domain-specific fractions of public medical data. MOLIERE, in contrast, utilizes information from over 24.5 million documents. At the heart of our approach lies a multi-modal and multi-relational network of biomedical objects extracted from several heterogeneous datasets from the National Center for Biotechnology Information (NCBI). These objects include but are not limited to scientific papers, keywords, genes, proteins, diseases, and diagnoses. We model hypotheses using Latent Dirichlet Allocation applied on abstracts found near shortest paths discovered within this network, and demonstrate the effectiveness of MOLIERE by performing hypothesis generation on historical data. Our network, implementation, and resulting data are all publicly available for the broad scientific community.

  19. The Method of Hypothesis in Plato's Philosophy

    Directory of Open Access Journals (Sweden)

    Malihe Aboie Mehrizi

    2016-09-01

    Full Text Available The article deals with the examination of method of hypothesis in Plato's philosophy. This method, respectively, will be examined in three dialogues of Meno, Phaedon and Republic in which it is explicitly indicated. It will be shown the process of change of Plato’s attitude towards the position and usage of the method of hypothesis in his realm of philosophy. In Meno, considering the geometry, Plato attempts to introduce a method that can be used in the realm of philosophy. But, ultimately in Republic, Plato’s special attention to the method and its importance in the philosophical investigations, leads him to revise it. Here, finally Plato introduces the particular method of philosophy, i.e., the dialectic

  20. Debates—Hypothesis testing in hydrology: Introduction

    Science.gov (United States)

    Blöschl, Günter

    2017-03-01

    This paper introduces the papers in the "Debates—Hypothesis testing in hydrology" series. The four articles in the series discuss whether and how the process of testing hypotheses leads to progress in hydrology. Repeated experiments with controlled boundary conditions are rarely feasible in hydrology. Research is therefore not easily aligned with the classical scientific method of testing hypotheses. Hypotheses in hydrology are often enshrined in computer models which are tested against observed data. Testability may be limited due to model complexity and data uncertainty. All four articles suggest that hypothesis testing has contributed to progress in hydrology and is needed in the future. However, the procedure is usually not as systematic as the philosophy of science suggests. A greater emphasis on a creative reasoning process on the basis of clues and explorative analyses is therefore needed.

  1. Multi-agent sequential hypothesis testing

    KAUST Repository

    Kim, Kwang-Ki K.

    2014-12-15

    This paper considers multi-agent sequential hypothesis testing and presents a framework for strategic learning in sequential games with explicit consideration of both temporal and spatial coordination. The associated Bayes risk functions explicitly incorporate costs of taking private/public measurements, costs of time-difference and disagreement in actions of agents, and costs of false declaration/choices in the sequential hypothesis testing. The corresponding sequential decision processes have well-defined value functions with respect to (a) the belief states for the case of conditional independent private noisy measurements that are also assumed to be independent identically distributed over time, and (b) the information states for the case of correlated private noisy measurements. A sequential investment game of strategic coordination and delay is also discussed as an application of the proposed strategic learning rules.

  2. Hypothesis testing of scientific Monte Carlo calculations

    Science.gov (United States)

    Wallerberger, Markus; Gull, Emanuel

    2017-11-01

    The steadily increasing size of scientific Monte Carlo simulations and the desire for robust, correct, and reproducible results necessitates rigorous testing procedures for scientific simulations in order to detect numerical problems and programming bugs. However, the testing paradigms developed for deterministic algorithms have proven to be ill suited for stochastic algorithms. In this paper we demonstrate explicitly how the technique of statistical hypothesis testing, which is in wide use in other fields of science, can be used to devise automatic and reliable tests for Monte Carlo methods, and we show that these tests are able to detect some of the common problems encountered in stochastic scientific simulations. We argue that hypothesis testing should become part of the standard testing toolkit for scientific simulations.

  3. Reverse hypothesis machine learning a practitioner's perspective

    CERN Document Server

    Kulkarni, Parag

    2017-01-01

    This book introduces a paradigm of reverse hypothesis machines (RHM), focusing on knowledge innovation and machine learning. Knowledge- acquisition -based learning is constrained by large volumes of data and is time consuming. Hence Knowledge innovation based learning is the need of time. Since under-learning results in cognitive inabilities and over-learning compromises freedom, there is need for optimal machine learning. All existing learning techniques rely on mapping input and output and establishing mathematical relationships between them. Though methods change the paradigm remains the same—the forward hypothesis machine paradigm, which tries to minimize uncertainty. The RHM, on the other hand, makes use of uncertainty for creative learning. The approach uses limited data to help identify new and surprising solutions. It focuses on improving learnability, unlike traditional approaches, which focus on accuracy. The book is useful as a reference book for machine learning researchers and professionals as ...

  4. Exploring heterogeneous market hypothesis using realized volatility

    Science.gov (United States)

    Chin, Wen Cheong; Isa, Zaidi; Mohd Nor, Abu Hassan Shaari

    2013-04-01

    This study investigates the heterogeneous market hypothesis using high frequency data. The cascaded heterogeneous trading activities with different time durations are modelled by the heterogeneous autoregressive framework. The empirical study indicated the presence of long memory behaviour and predictability elements in the financial time series which supported heterogeneous market hypothesis. Besides the common sum-of-square intraday realized volatility, we also advocated two power variation realized volatilities in forecast evaluation and risk measurement in order to overcome the possible abrupt jumps during the credit crisis. Finally, the empirical results are used in determining the market risk using the value-at-risk approach. The findings of this study have implications for informationally market efficiency analysis, portfolio strategies and risk managements.

  5. Water Taxation and the Double Dividend Hypothesis

    OpenAIRE

    Nicholas Kilimani

    2014-01-01

    The double dividend hypothesis contends that environmental taxes have the potential to yield multiple benefits for the economy. However, empirical evidence of the potential impacts of environmental taxation in developing countries is still limited. This paper seeks to contribute to the literature by exploring the impact of a water tax in a developing country context, with Uganda as a case study. Policy makers in Uganda are exploring ways of raising revenue by taxing environmental goods such a...

  6. [Working memory, phonological awareness and spelling hypothesis].

    Science.gov (United States)

    Gindri, Gigiane; Keske-Soares, Márcia; Mota, Helena Bolli

    2007-01-01

    Working memory, phonological awareness and spelling hypothesis. To verify the relationship between working memory, phonological awareness and spelling hypothesis in pre-school children and first graders. Participants of this study were 90 students, belonging to state schools, who presented typical linguistic development. Forty students were preschoolers, with the average age of six and 50 students were first graders, with the average age of seven. Participants were submitted to an evaluation of the working memory abilities based on the Working Memory Model (Baddeley, 2000), involving phonological loop. Phonological loop was evaluated using the Auditory Sequential Test, subtest 5 of Illinois Test of Psycholinguistic Abilities (ITPA), Brazilian version (Bogossian & Santos, 1977), and the Meaningless Words Memory Test (Kessler, 1997). Phonological awareness abilities were investigated using the Phonological Awareness: Instrument of Sequential Assessment (CONFIAS - Moojen et al., 2003), involving syllabic and phonemic awareness tasks. Writing was characterized according to Ferreiro & Teberosky (1999). Preschoolers presented the ability of repeating sequences of 4.80 digits and 4.30 syllables. Regarding phonological awareness, the performance in the syllabic level was of 19.68 and in the phonemic level was of 8.58. Most of the preschoolers demonstrated to have a pre-syllabic writing hypothesis. First graders repeated, in average, sequences of 5.06 digits and 4.56 syllables. These children presented a phonological awareness of 31.12 in the syllabic level and of 16.18 in the phonemic level, and demonstrated to have an alphabetic writing hypothesis. The performance of working memory, phonological awareness and spelling level are inter-related, as well as being related to chronological age, development and scholarity.

  7. Privacy on Hypothesis Testing in Smart Grids

    OpenAIRE

    Li, Zuxing; Oechtering, Tobias

    2015-01-01

    In this paper, we study the problem of privacy information leakage in a smart grid. The privacy risk is assumed to be caused by an unauthorized binary hypothesis testing of the consumer's behaviour based on the smart meter readings of energy supplies from the energy provider. Another energy supplies are produced by an alternative energy source. A controller equipped with an energy storage device manages the energy inflows to satisfy the energy demand of the consumer. We study the optimal ener...

  8. Box-particle probability hypothesis density filtering

    OpenAIRE

    Schikora, M.; Gning, A.; Mihaylova, L.; Cremers, D.; Koch, W.

    2014-01-01

    This paper develops a novel approach for multitarget tracking, called box-particle probability hypothesis density filter (box-PHD filter). The approach is able to track multiple targets and estimates the unknown number of targets. Furthermore, it is capable of dealing with three sources of uncertainty: stochastic, set-theoretic, and data association uncertainty. The box-PHD filter reduces the number of particles significantly, which improves the runtime considerably. The small number of box-p...

  9. Quantum effects and hypothesis of cosmic censorship

    International Nuclear Information System (INIS)

    Parnovskij, S.L.

    1989-01-01

    It is shown that filamentary characteristics with linear mass of less than 10 25 g/cm distort slightly the space-time at distances, exceeding Planck ones. Their formation doesn't change vacuum energy and doesn't lead to strong quantum radiation. Therefore, the problem of their occurrence can be considered within the framework of classical collapse. Quantum effects can be ignored when considering the problem of validity of cosmic censorship hypothesis

  10. Supporting Transition

    Science.gov (United States)

    Qureshi, Asima; Petrucco, James

    2018-01-01

    Meadowbrook Primary School has explored the use of The Teacher Assessment in Primary Science (TAPS) to support transition, initially for transfer to secondary school and now for transition from Early Years Foundation Stage (EYFS) into Key Stage 1 (ages 5-7). This article will consider an example of a secondary transition project and discuss the…

  11. The (not so) immortal strand hypothesis.

    Science.gov (United States)

    Tomasetti, Cristian; Bozic, Ivana

    2015-03-01

    Non-random segregation of DNA strands during stem cell replication has been proposed as a mechanism to minimize accumulated genetic errors in stem cells of rapidly dividing tissues. According to this hypothesis, an "immortal" DNA strand is passed to the stem cell daughter and not the more differentiated cell, keeping the stem cell lineage replication error-free. After it was introduced, experimental evidence both in favor and against the hypothesis has been presented. Using a novel methodology that utilizes cancer sequencing data we are able to estimate the rate of accumulation of mutations in healthy stem cells of the colon, blood and head and neck tissues. We find that in these tissues mutations in stem cells accumulate at rates strikingly similar to those expected without the protection from the immortal strand mechanism. Utilizing an approach that is fundamentally different from previous efforts to confirm or refute the immortal strand hypothesis, we provide evidence against non-random segregation of DNA during stem cell replication. Our results strongly suggest that parental DNA is passed randomly to stem cell daughters and provides new insight into the mechanism of DNA replication in stem cells. Copyright © 2015. Published by Elsevier B.V.

  12. A test of the orthographic recoding hypothesis

    Science.gov (United States)

    Gaygen, Daniel E.

    2003-04-01

    The Orthographic Recoding Hypothesis [D. E. Gaygen and P. A. Luce, Percept. Psychophys. 60, 465-483 (1998)] was tested. According to this hypothesis, listeners recognize spoken words heard for the first time by mapping them onto stored representations of the orthographic forms of the words. Listeners have a stable orthographic representation of words, but no phonological representation, when those words have been read frequently but never heard or spoken. Such may be the case for low frequency words such as jargon. Three experiments using visually and auditorily presented nonword stimuli tested this hypothesis. The first two experiments were explicit tests of memory (old-new tests) for words presented visually. In the first experiment, the recognition of auditorily presented nonwords was facilitated when they previously appeared on a visually presented list. The second experiment was similar, but included a concurrent articulation task during a visual word list presentation, thus preventing covert rehearsal of the nonwords. The results were similar to the first experiment. The third experiment was an indirect test of memory (auditory lexical decision task) for visually presented nonwords. Auditorily presented nonwords were identified as nonwords significantly more slowly if they had previously appeared on the visually presented list accompanied by a concurrent articulation task.

  13. Consumer health information seeking as hypothesis testing.

    Science.gov (United States)

    Keselman, Alla; Browne, Allen C; Kaufman, David R

    2008-01-01

    Despite the proliferation of consumer health sites, lay individuals often experience difficulty finding health information online. The present study attempts to understand users' information seeking difficulties by drawing on a hypothesis testing explanatory framework. It also addresses the role of user competencies and their interaction with internet resources. Twenty participants were interviewed about their understanding of a hypothetical scenario about a family member suffering from stable angina and then searched MedlinePlus consumer health information portal for information on the problem presented in the scenario. Participants' understanding of heart disease was analyzed via semantic analysis. Thematic coding was used to describe information seeking trajectories in terms of three key strategies: verification of the primary hypothesis, narrowing search within the general hypothesis area and bottom-up search. Compared to an expert model, participants' understanding of heart disease involved different key concepts, which were also differently grouped and defined. This understanding provided the framework for search-guiding hypotheses and results interpretation. Incorrect or imprecise domain knowledge led individuals to search for information on irrelevant sites, often seeking out data to confirm their incorrect initial hypotheses. Online search skills enhanced search efficiency, but did not eliminate these difficulties. Regardless of their web experience and general search skills, lay individuals may experience difficulty with health information searches. These difficulties may be related to formulating and evaluating hypotheses that are rooted in their domain knowledge. Informatics can provide support at the levels of health information portals, individual websites, and consumer education tools.

  14. Epidemiology applied to health physics

    International Nuclear Information System (INIS)

    1983-01-01

    The technical program of the mid-year meeting of the Health Physics Society, entitled Epidemiology Applied to Health physics, was developed to meet three objectives: (1) give health physicists a deeper understanding of the basics of epidemiological methods and their use in developing standards, regulations, and criteria and in risk assessment; (2) present current reports on recently completed or on-going epidemiology studies; and (3) encourage greater interaction between the health physics and epidemiology disciplines. Included are studies relating methods in epidemiology to radiation protection standards, risk assessment from exposure to bone-seekers, from occupational exposures in mines, mills and nuclear facilities, and from radioactivity in building materials

  15. Early hominins in Europe: The Galerian migration hypothesis

    Science.gov (United States)

    Muttoni, Giovanni; Scardia, Giancarlo; Kent, Dennis V.

    2018-01-01

    Our updated review of sites bearing hominin remains and/or tools from Europe, including new findings from the Balkans, still indicates that the only compelling evidence of main hominin presence in these regions was only since ∼0.9 million years ago (Ma), bracketed by the end of the Jaramillo geomagnetic polarity subchron (0.99 Ma) and the Brunhes-Matuyama polarity chron boundary (0.78 Ma). This time window straddled the late Early Pleistocene climate transition (EPT) at the onset of enhanced glacial/interglacial activity that reverberated worldwide. Europe may have become initially populated during the EPT when, possibly for the first time in the Pleistocene, vast and exploitable ecosystems were generated along the eustatically emergent Po-Danube terrestrial conduit. These newly formed settings, characterized by stable terrestrial lowlands with open grasslands and reduced woody cover especially during glacial/interglacial transitions, are regarded as optimal ecosystems for several large Galerian immigrant mammals such as African and Asian megaherbivores, possibly linked with hominins in a common food web, to expand into en route to Europe. The question of when hominins first arrived in Europe thus places the issue in the context of changes in climate, paleogeography and faunal associations as potential environmental drivers and controlling agents in a specific time frame, a key feature of the Galerian migration hypothesis.

  16. Epidemiology and ionizing radiations

    International Nuclear Information System (INIS)

    Bourguignon, M.; Masse, R.; Slama, R.; Spira, A.; Timarche, M.; Laurier, D.; Billon, S.; Rogel, A.; Telle Lamberton, M.; Catelinois, O.; Thierry, I.; Grosche, B.; Ron, E.; Vathaire, F. de; Cherie Challine, L.; Donadieu, J.; Pirard, Ph.; Bloch, J.; Setbon, M.

    2004-01-01

    The ionizing radiations have effects on living being. The determinist effects appear since a threshold of absorbed dose of radiation is reached. In return, the stochastic effects of ionizing radiations are these ones whom apparition cannot be described except in terms of probabilities. They are in one hand, cancers and leukemia, on the other hand, lesions of the genome potentially transmissible to the descendants. That is why epidemiology, defined by specialists as the science that studies the frequency and distribution of illness in time and space, the contribution of factors that determine this frequency and this distribution among human populations. This issue gathers and synthesizes the knowledge and examines the difficulties of methodologies. It allows to give its true place to epidemiology. (N.C.)

  17. Epidemiology of Gout

    Science.gov (United States)

    Choi, Hyon

    2014-01-01

    Synopsis Gout is the most prevalent inflammatory arthritis in men. The findings of several epidemiological studies from a diverse range of countries suggest that the prevalence of gout has risen over the last few decades. Whilst incidence data are scarce, data from the US suggests that the incidence of gout is also rising. Evidence from prospective epidemiological studies has confirmed dietary factors (animal purines, alcohol and fructose), obesity, the metabolic syndrome, hypertension, diuretic use, and chronic kidney disease as clinically relevant risk factors for hyperuricemia and gout. Low-fat dairy products, coffee, and vitamin C appear to have a protective effect. Further prospective studies are required to examine other proposed risk factors for hyperuricaemia and gout such as the use of β-blockers and angiotension-II receptor antagonists (other than losartan), obstructive sleep apnoea, and osteoarthritis, and putative protective factors such as calcium-channel blockers and losartan. PMID:24703341

  18. Epidemiological studies on syncope

    DEFF Research Database (Denmark)

    Ruwald, Martin Huth

    2013-01-01

    of the patients play an essential role. In epidemiology these factors have major impact on the outcome of the patients. Until recently, even the definition of syncope differed from one study to another which has made literature reviews difficult. Traditionally the data on epidemiology of syncope has been taken...... from smaller studies from different clinical settings with wide differences in patient morbidity. Through the extensive Danish registries we examined the characteristics and prognosis of the patients hospitalized due to syncope in a nationwide study. The aims of the present thesis were to investigate......, prevalence and cardiovascular factors associated with the risk of syncope, 4) the prognosis in healthy individuals discharged after syncope, and 5) the prognosis of patients after syncope and evaluation of the CHADS2 score as a tool for short- and long-term risk prediction. The first studies of the present...

  19. The leukemias: Epidemiologic aspects

    International Nuclear Information System (INIS)

    Linet, M.S.

    1984-01-01

    Particularly geared to physicians and cancer researchers, this study of the epidemiology and etiology of leukemia analyzes the four major leukemia subtypes in terms of genetic and familial determinant factors and examines the incidence, distribution and frequency of reported leukemia clusters. Linet discusses the connection between other types of malignancies, their treatments, and the subsequent development of leukemia and evaluates the impact on leukemia onset of such environmental factors as radiation therapy, drugs, and occupational hazards

  20. Worldwide Report, Epidemiology

    Science.gov (United States)

    1985-11-22

    caused by ingesting eggs of the pork tapeworm, Taenia solium . It has been described as the most com- mon parasitic disease of the central nervous...rather difficult to detect in stool specimens and at this stage it is impossible to distinguish between T. solium and T. saginata eggs either by...Knowledge and Perspectives, pp. 25-38. Academic Press, New York. 12. Pawlowskz S. (1982). Epidemiology and prevention of Taenia saginata infec- tion. In

  1. Epidemiology and moral philosophy.

    OpenAIRE

    Westrin, C G; Nilstun, T; Smedby, B; Haglund, B

    1992-01-01

    To an increasing extent ethical controversies affect and sometimes obstruct public health work and epidemiological research. In order to improve communication between the concerned parties a model for identification and analysis of ethical conflicts in individual-based research has been worked out in co-operation between epidemiologists and moral philosophers. The model has two dimensions. One dimension specifies relevant ethical principles (as beneficence, non-maleficence, autonomy and justi...

  2. Tests of the planetary hypothesis for PTFO 8-8695b

    DEFF Research Database (Denmark)

    Yu, Liang; Winn, Joshua N.; Gillon, Michaël

    2015-01-01

    The T Tauri star PTFO 8-8695 exhibits periodic fading events that have been interpreted as the transits of a giant planet on a precessing orbit. Here we present three tests of the planet hypothesis. First, we sought evidence for the secular changes in light-curve morphology that are predicted...... planetary orbit. Our spectroscopy also revealed strong, time-variable, high-velocity H{\\alpha} and Ca H & K emission features. All these observations cast doubt on the planetary hypothesis, and suggest instead that the fading events represent starspots, eclipses by circumstellar dust, or occultations...

  3. Updating the lamellar hypothesis of hippocampal organization

    Directory of Open Access Journals (Sweden)

    Robert S Sloviter

    2012-12-01

    Full Text Available In 1971, Andersen and colleagues proposed that excitatory activity in the entorhinal cortex propagates topographically to the dentate gyrus, and on through a trisynaptic circuit lying within transverse hippocampal slices or lamellae [Andersen, Bliss, and Skrede. 1971. Lamellar organization of hippocampal pathways. Exp Brain Res 13, 222-238]. In this way, a relatively simple structure might mediate complex functions in a manner analogous to the way independent piano keys can produce a nearly infinite variety of unique outputs. The lamellar hypothesis derives primary support from the lamellar distribution of dentate granule cell axons (the mossy fibers, which innervate dentate hilar neurons and area CA3 pyramidal cells and interneurons within the confines of a thin transverse hippocampal segment. Following the initial formulation of the lamellar hypothesis, anatomical studies revealed that unlike granule cells, hilar mossy cells, CA3 pyramidal cells, and Layer II entorhinal cells all form axonal projections that are more divergent along the longitudinal axis than the clearly lamellar mossy fiber pathway. The existence of pathways with translamellar distribution patterns has been interpreted, incorrectly in our view, as justifying outright rejection of the lamellar hypothesis [Amaral and Witter. 1989. The three-dimensional organization of the hippocampal formation: a review of anatomical data. Neuroscience 31, 571-591]. We suggest that the functional implications of longitudinally-projecting axons depend not on whether they exist, but on what they do. The observation that focal granule cell layer discharges normally inhibit, rather than excite, distant granule cells suggests that longitudinal axons in the dentate gyrus may mediate "lateral" inhibition and define lamellar function, rather than undermine it. In this review, we attempt a reconsideration of the evidence that most directly impacts the physiological concept of hippocampal lamellar

  4. Hypothesis Testing as an Act of Rationality

    Science.gov (United States)

    Nearing, Grey

    2017-04-01

    Statistical hypothesis testing is ad hoc in two ways. First, setting probabilistic rejection criteria is, as Neyman (1957) put it, an act of will rather than an act of rationality. Second, physical theories like conservation laws do not inherently admit probabilistic predictions, and so we must use what are called epistemic bridge principles to connect model predictions with the actual methods of hypothesis testing. In practice, these bridge principles are likelihood functions, error functions, or performance metrics. I propose that the reason we are faced with these problems is because we have historically failed to account for a fundamental component of basic logic - namely the portion of logic that explains how epistemic states evolve in the presence of empirical data. This component of Cox' (1946) calculitic logic is called information theory (Knuth, 2005), and adding information theory our hypothetico-deductive account of science yields straightforward solutions to both of the above problems. This also yields a straightforward method for dealing with Popper's (1963) problem of verisimilitude by facilitating a quantitative approach to measuring process isomorphism. In practice, this involves data assimilation. Finally, information theory allows us to reliably bound measures of epistemic uncertainty, thereby avoiding the problem of Bayesian incoherency under misspecified priors (Grünwald, 2006). I therefore propose solutions to four of the fundamental problems inherent in both hypothetico-deductive and/or Bayesian hypothesis testing. - Neyman (1957) Inductive Behavior as a Basic Concept of Philosophy of Science. - Cox (1946) Probability, Frequency and Reasonable Expectation. - Knuth (2005) Lattice Duality: The Origin of Probability and Entropy. - Grünwald (2006). Bayesian Inconsistency under Misspecification. - Popper (1963) Conjectures and Refutations: The Growth of Scientific Knowledge.

  5. The conscious access hypothesis: Explaining the consciousness.

    Science.gov (United States)

    Prakash, Ravi

    2008-01-01

    The phenomenon of conscious awareness or consciousness is complicated but fascinating. Although this concept has intrigued the mankind since antiquity, exploration of consciousness from scientific perspectives is not very old. Among myriad of theories regarding nature, functions and mechanism of consciousness, off late, cognitive theories have received wider acceptance. One of the most exciting hypotheses in recent times has been the "conscious access hypotheses" based on the "global workspace model of consciousness". It underscores an important property of consciousness, the global access of information in cerebral cortex. Present article reviews the "conscious access hypothesis" in terms of its theoretical underpinnings as well as experimental supports it has received.

  6. Interstellar colonization and the zoo hypothesis

    International Nuclear Information System (INIS)

    Jones, E.M.

    1978-01-01

    Michael Hart and others have pointed out that current estimates of the number of technological civilizations arisen in the Galaxy since its formation is in fundamental conflict with the expectation that such a civilization could colonize and utilize the entire Galaxy in 10 to 20 million years. This dilemma can be called Hart's paradox. Resolution of the paradox requires that one or more of the following are true: we are the Galaxy's first technical civilization; interstellar travel is immensely impractical or simply impossible; technological civilizations are very short-lived; or we inhabit a wildnerness preserve. The latter is the zoo hypothesis

  7. RANDOM WALK HYPOTHESIS IN FINANCIAL MARKETS

    Directory of Open Access Journals (Sweden)

    Nicolae-Marius JULA

    2017-05-01

    Full Text Available Random walk hypothesis states that the stock market prices do not follow a predictable trajectory, but are simply random. If you are trying to predict a random set of data, one should test for randomness, because, despite the power and complexity of the used models, the results cannot be trustworthy. There are several methods for testing these hypotheses and the use of computational power provided by the R environment makes the work of the researcher easier and with a cost-effective approach. The increasing power of computing and the continuous development of econometric tests should give the potential investors new tools in selecting commodities and investing in efficient markets.

  8. Confluence Model or Resource Dilution Hypothesis?

    DEFF Research Database (Denmark)

    Jæger, Mads

    have a negative effect on educational attainment most studies cannot distinguish empirically between the CM and the RDH. In this paper, I use the different theoretical predictions in the CM and the RDH on the role of cognitive ability as a partial or complete mediator of the sibship size effect......Studies on family background often explain the negative effect of sibship size on educational attainment by one of two theories: the Confluence Model (CM) or the Resource Dilution Hypothesis (RDH). However, as both theories – for substantively different reasons – predict that sibship size should...

  9. Set theory and the continuum hypothesis

    CERN Document Server

    Cohen, Paul J

    2008-01-01

    This exploration of a notorious mathematical problem is the work of the man who discovered the solution. The independence of the continuum hypothesis is the focus of this study by Paul J. Cohen. It presents not only an accessible technical explanation of the author's landmark proof but also a fine introduction to mathematical logic. An emeritus professor of mathematics at Stanford University, Dr. Cohen won two of the most prestigious awards in mathematics: in 1964, he was awarded the American Mathematical Society's Bôcher Prize for analysis; and in 1966, he received the Fields Medal for Logic.

  10. Statistical hypothesis testing with SAS and R

    CERN Document Server

    Taeger, Dirk

    2014-01-01

    A comprehensive guide to statistical hypothesis testing with examples in SAS and R When analyzing datasets the following questions often arise:Is there a short hand procedure for a statistical test available in SAS or R?If so, how do I use it?If not, how do I program the test myself? This book answers these questions and provides an overview of the most commonstatistical test problems in a comprehensive way, making it easy to find and performan appropriate statistical test. A general summary of statistical test theory is presented, along with a basicdescription for each test, including the

  11. Transition radiation and transition scattering

    International Nuclear Information System (INIS)

    Ginzburg, V.L.

    1982-01-01

    Transition radiation is a process of a rather general character. It occurs when some source, which does not have a proper frequency (for example, a charge) moves at a constant velocity in an inhomogeneous and (or) nonstationary medium or near such a medium. The simplest type of transition radiation takes place when a charge crosses a boundary between two media (the role of one of the media may be played by vacuum). In the case of periodic variation of the medium, transition radiation possesses some specific features (resonance transition radiation or transition scattering). Transition scattering occurs, in particular, when a permittivity wave falls onto an nonmoving (fixed) charge. Transition scattering is closely connected with transition bremsstrahlung radiation. All these transition processes are essential for plasma physics. Transition radiation and transition scattering have analogues outside the framework of electrodynamics (like in the case of Vavilov-Cherenkov radiation). In the present report the corresponding range of phenomena is elucidated, as far as possible, in a generally physical aspect. (Auth.)

  12. The Sit-and-Wait Hypothesis in Bacterial Pathogens: A Theoretical Study of Durability and Virulence

    Directory of Open Access Journals (Sweden)

    Liang Wang

    2017-11-01

    Full Text Available The intriguing sit-and-wait hypothesis predicts that bacterial durability in the external environment is positively correlated with their virulence. Since its first proposal in 1987, the hypothesis has been spurring debates in terms of its validity in the field of bacterial virulence. As a special case of the vector-borne transmission versus virulence tradeoff, where vector is now replaced by environmental longevity, there are only sporadic studies over the last three decades showing that environmental durability is possibly linked with virulence. However, no systematic study of these works is currently available and epidemiological analysis has not been updated for the sit-and-wait hypothesis since the publication of Walther and Ewald’s (2004 review. In this article, we put experimental evidence, epidemiological data and theoretical analysis together to support the sit-and-wait hypothesis. According to the epidemiological data in terms of gain and loss of virulence (+/- and durability (+/- phenotypes, we classify bacteria into four groups, which are: sit-and-wait pathogens (++, vector-borne pathogens (+-, obligate-intracellular bacteria (--, and free-living bacteria (-+. After that, we dive into the abundant bacterial proteomic data with the assistance of bioinformatics techniques in order to investigate the two factors at molecular level thanks to the fast development of high-throughput sequencing technology. Sequences of durability-related genes sourced from Gene Ontology and UniProt databases and virulence factors collected from Virulence Factor Database are used to search 20 corresponding bacterial proteomes in batch mode for homologous sequences via the HMMER software package. Statistical analysis only identified a modest, and not statistically significant correlation between mortality and survival time for eight non-vector-borne bacteria with sit-and-wait potentials. Meanwhile, through between-group comparisons, bacteria with higher

  13. The hygiene hypothesis in autoimmunity: the role of pathogens and commensals.

    Science.gov (United States)

    Bach, Jean-François

    2018-02-01

    The incidence of autoimmune diseases has been steadily rising. Concomitantly, the incidence of most infectious diseases has declined. This observation gave rise to the hygiene hypothesis, which postulates that a reduction in the frequency of infections contributes directly to the increase in the frequency of autoimmune and allergic diseases. This hypothesis is supported by robust epidemiological data, but the underlying mechanisms are unclear. Pathogens are known to be important, as autoimmune disease is prevented in various experimental models by infection with different bacteria, viruses and parasites. Gut commensal bacteria also play an important role: dysbiosis of the gut flora is observed in patients with autoimmune diseases, although the causal relationship with the occurrence of autoimmune diseases has not been established. Both pathogens and commensals act by stimulating immunoregulatory pathways. Here, I discuss the importance of innate immune receptors, in particular Toll-like receptors, in mediating the protective effect of pathogens and commensals on autoimmunity.

  14. Hypothesis-driven physical examination curriculum.

    Science.gov (United States)

    Allen, Sharon; Olson, Andrew; Menk, Jeremiah; Nixon, James

    2017-12-01

    Medical students traditionally learn physical examination skills as a rote list of manoeuvres. Alternatives like hypothesis-driven physical examination (HDPE) may promote students' understanding of the contribution of physical examination to diagnostic reasoning. We sought to determine whether first-year medical students can effectively learn to perform a physical examination using an HDPE approach, and then tailor the examination to specific clinical scenarios. Medical students traditionally learn physical examination skills as a rote list of manoeuvres CONTEXT: First-year medical students at the University of Minnesota were taught both traditional and HDPE approaches during a required 17-week clinical skills course in their first semester. The end-of-course evaluation assessed HDPE skills: students were assigned one of two cardiopulmonary cases. Each case included two diagnostic hypotheses. During an interaction with a standardised patient, students were asked to select physical examination manoeuvres in order to make a final diagnosis. Items were weighted and selection order was recorded. First-year students with minimal pathophysiology performed well. All students selected the correct diagnosis. Importantly, students varied the order when selecting examination manoeuvres depending on the diagnoses under consideration, demonstrating early clinical decision-making skills. An early introduction to HDPE may reinforce physical examination skills for hypothesis generation and testing, and can foster early clinical decision-making skills. This has important implications for further research in physical examination instruction. © 2016 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

  15. A default Bayesian hypothesis test for mediation.

    Science.gov (United States)

    Nuijten, Michèle B; Wetzels, Ruud; Matzke, Dora; Dolan, Conor V; Wagenmakers, Eric-Jan

    2015-03-01

    In order to quantify the relationship between multiple variables, researchers often carry out a mediation analysis. In such an analysis, a mediator (e.g., knowledge of a healthy diet) transmits the effect from an independent variable (e.g., classroom instruction on a healthy diet) to a dependent variable (e.g., consumption of fruits and vegetables). Almost all mediation analyses in psychology use frequentist estimation and hypothesis-testing techniques. A recent exception is Yuan and MacKinnon (Psychological Methods, 14, 301-322, 2009), who outlined a Bayesian parameter estimation procedure for mediation analysis. Here we complete the Bayesian alternative to frequentist mediation analysis by specifying a default Bayesian hypothesis test based on the Jeffreys-Zellner-Siow approach. We further extend this default Bayesian test by allowing a comparison to directional or one-sided alternatives, using Markov chain Monte Carlo techniques implemented in JAGS. All Bayesian tests are implemented in the R package BayesMed (Nuijten, Wetzels, Matzke, Dolan, & Wagenmakers, 2014).

  16. Gaussian Hypothesis Testing and Quantum Illumination.

    Science.gov (United States)

    Wilde, Mark M; Tomamichel, Marco; Lloyd, Seth; Berta, Mario

    2017-09-22

    Quantum hypothesis testing is one of the most basic tasks in quantum information theory and has fundamental links with quantum communication and estimation theory. In this paper, we establish a formula that characterizes the decay rate of the minimal type-II error probability in a quantum hypothesis test of two Gaussian states given a fixed constraint on the type-I error probability. This formula is a direct function of the mean vectors and covariance matrices of the quantum Gaussian states in question. We give an application to quantum illumination, which is the task of determining whether there is a low-reflectivity object embedded in a target region with a bright thermal-noise bath. For the asymmetric-error setting, we find that a quantum illumination transmitter can achieve an error probability exponent stronger than a coherent-state transmitter of the same mean photon number, and furthermore, that it requires far fewer trials to do so. This occurs when the background thermal noise is either low or bright, which means that a quantum advantage is even easier to witness than in the symmetric-error setting because it occurs for a larger range of parameters. Going forward from here, we expect our formula to have applications in settings well beyond those considered in this paper, especially to quantum communication tasks involving quantum Gaussian channels.

  17. Inoculation stress hypothesis of environmental enrichment.

    Science.gov (United States)

    Crofton, Elizabeth J; Zhang, Yafang; Green, Thomas A

    2015-02-01

    One hallmark of psychiatric conditions is the vast continuum of individual differences in susceptibility vs. resilience resulting from the interaction of genetic and environmental factors. The environmental enrichment paradigm is an animal model that is useful for studying a range of psychiatric conditions, including protective phenotypes in addiction and depression models. The major question is how environmental enrichment, a non-drug and non-surgical manipulation, can produce such robust individual differences in such a wide range of behaviors. This paper draws from a variety of published sources to outline a coherent hypothesis of inoculation stress as a factor producing the protective enrichment phenotypes. The basic tenet suggests that chronic mild stress from living in a complex environment and interacting non-aggressively with conspecifics can inoculate enriched rats against subsequent stressors and/or drugs of abuse. This paper reviews the enrichment phenotypes, mulls the fundamental nature of environmental enrichment vs. isolation, discusses the most appropriate control for environmental enrichment, and challenges the idea that cortisol/corticosterone equals stress. The intent of the inoculation stress hypothesis of environmental enrichment is to provide a scaffold with which to build testable hypotheses for the elucidation of the molecular mechanisms underlying these protective phenotypes and thus provide new therapeutic targets to treat psychiatric/neurological conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Athlete's Heart: Is the Morganroth Hypothesis Obsolete?

    Science.gov (United States)

    Haykowsky, Mark J; Samuel, T Jake; Nelson, Michael D; La Gerche, Andre

    2018-05-01

    In 1975, Morganroth and colleagues reported that the increased left ventricular (LV) mass in highly trained endurance athletes versus nonathletes was primarily due to increased end-diastolic volume while the increased LV mass in resistance trained athletes was solely due to an increased LV wall thickness. Based on the divergent remodelling patterns observed, Morganroth and colleagues hypothesised that the increased "volume" load during endurance exercise may be similar to that which occurs in patients with mitral or aortic regurgitation while the "pressure" load associated with performing a Valsalva manoeuvre (VM) during resistance exercise may mimic the stress imposed on the heart by systemic hypertension or aortic stenosis. Despite widespread acceptance of the four-decade old Morganroth hypothesis in sports cardiology, some investigators have questioned whether such a divergent "athlete's heart" phenotype exists. Given this uncertainty, the purpose of this brief review is to re-evaluate the Morganroth hypothesis regarding: i) the acute effects of resistance exercise performed with a brief VM on LV wall stress, and the patterns of LV remodelling in resistance-trained athletes; ii) the acute effects of endurance exercise on biventricular wall stress, and the time course and pattern of LV and right ventricular (RV) remodelling with endurance training; and iii) the value of comparing "loading" conditions between athletes and patients with cardiac pathology. Copyright © 2018. Published by Elsevier B.V.

  19. The Debt Overhang Hypothesis: Evidence from Pakistan

    Directory of Open Access Journals (Sweden)

    Shah Muhammad Imran

    2016-04-01

    Full Text Available This study investigates the debt overhang hypothesis for Pakistan in the period 1960-2007. The study examines empirically the dynamic behaviour of GDP, debt services, the employed labour force and investment using the time series concepts of unit roots, cointegration, error correlation and causality. Our findings suggest that debt-servicing has a negative impact on the productivity of both labour and capital, and that in turn has adversely affected economic growth. By severely constraining the ability of the country to service debt, this lends support to the debt-overhang hypothesis in Pakistan. The long run relation between debt services and economic growth implies that future increases in output will drain away in form of high debt service payments to lender country as external debt acts like a tax on output. More specifically, foreign creditors will benefit more from the rise in productivity than will domestic producers and labour. This suggests that domestic labour and capital are the ultimate losers from this heavy debt burden.

  20. Roots and Route of the Artification Hypothesis

    Directory of Open Access Journals (Sweden)

    Ellen Dissanayake

    2017-08-01

    Full Text Available Over four decades, my ideas about the arts in human evolution have themselves evolved, from an original notion of art as a human behaviour of “making special” to a full-fledged hypothesis of artification. A summary of the gradual developmental path (or route of the hypothesis, based on ethological principles and concepts, is given, and an argument presented in which artification is described as an exaptation whose roots lie in adaptive features of ancestral mother–infant interaction that contributed to infant survival and maternal reproductive success. I show how the interaction displays features of a ritualised behavior whose operations (formalization, repetition, exaggeration, and elaboration can be regarded as characteristic elements of human ritual ceremonies as well as of art (including song, dance, performance, literary language, altered surroundings, and other examples of making ordinary sounds, movement, language, environments, objects, and bodies extraordinary. Participation in these behaviours in ritual practices served adaptive ends in early Homo by coordinating brain and body states, and thereby emotionally bonding members of a group in common cause as well as reducing existential anxiety in individuals. A final section situates artification within contemporary philosophical and popular ideas of art, claiming that artifying is not a synonym for or definition of art but foundational to any evolutionary discussion of artistic/aesthetic behaviour.

  1. Urbanization and the more-individuals hypothesis.

    Science.gov (United States)

    Chiari, Claudia; Dinetti, Marco; Licciardello, Cinzia; Licitra, Gaetano; Pautasso, Marco

    2010-03-01

    1. Urbanization is a landscape process affecting biodiversity world-wide. Despite many urban-rural studies of bird assemblages, it is still unclear whether more species-rich communities have more individuals, regardless of the level of urbanization. The more-individuals hypothesis assumes that species-rich communities have larger populations, thus reducing the chance of local extinctions. 2. Using newly collated avian distribution data for 1 km(2) grid cells across Florence, Italy, we show a significantly positive relationship between species richness and assemblage abundance for the whole urban area. This richness-abundance relationship persists for the 1 km(2) grid cells with less than 50% of urbanized territory, as well as for the remaining grid cells, with no significant difference in the slope of the relationship. These results support the more-individuals hypothesis as an explanation of patterns in species richness, also in human modified and fragmented habitats. 3. However, the intercept of the species richness-abundance relationship is significantly lower for highly urbanized grid cells. Our study confirms that urban communities have lower species richness but counters the common notion that assemblages in densely urbanized ecosystems have more individuals. In Florence, highly inhabited areas show fewer species and lower assemblage abundance. 4. Urbanized ecosystems are an ongoing large-scale natural experiment which can be used to test ecological theories empirically.

  2. Worldwide epidemiology of fibromyalgia.

    Science.gov (United States)

    Queiroz, Luiz Paulo

    2013-08-01

    Studying the epidemiology of fibromyalgia (FM) is very important to understand the impact of this disorder on persons, families and society. The recent modified 2010 classification criteria of the American College of Rheumatology (ACR), without the need of tender points palpation, allows that larger and nationwide surveys may be done, worldwide. This article reviews the prevalence and incidence studies done in the general population, in several countries/continents, the prevalence of FM in special groups/settings, the association of FM with some sociodemographic characteristics of the population, and the comorbidity of FM with others disorders, especially with headaches.

  3. Epidemiology of Posttraumatic Osteoarthritis.

    Science.gov (United States)

    Thomas, Abbey C; Hubbard-Turner, Tricia; Wikstrom, Erik A; Palmieri-Smith, Riann M

    2017-06-02

    Osteoarthritis is a leading cause of disability whose prevalence and incidence continue to increase. History of joint injury represents an important risk factor for posttraumatic osteoarthritis and is a significant contributor to the rapidly growing percentage of the population with osteoarthritis. This review will present the epidemiology associated with posttraumatic osteoarthritis, with particular emphasis on the knee and ankle joints. It is important to understand the effect of posttraumatic osteoarthritis on the population so that sufficient resources can be devoted to countering the disease and promoting optimal long-term health for patients after joint injury.

  4. Molecular epidemiology of ascariasis

    DEFF Research Database (Denmark)

    Betson, Martha; Halstead, Fennella; Nejsum, Peter

      We are using molecular epidemiology techniques to study the population structure of Ascaris obtained from humans and pigs. Worms were obtained from human hosts on Zanzibar and in Uganda, Bangladesh, Guatemala and Nepal and Ascaris from pigs were collected from in Uganda, Tanzania, Denmark......, Guatemala and the Philippines. Genomic DNA was extracted from each worm and a 450 base pair fragment of the mitochondrial cytochrome oxidase gene subunit 1 (COI) was PCR amplified. The products were sequenced from both strands and sequences were manually edited. Fifty different Ascaris CO1 haplotypes were...

  5. The Younger Dryas impact hypothesis: A requiem

    Science.gov (United States)

    Pinter, Nicholas; Scott, Andrew C.; Daulton, Tyrone L.; Podoll, Andrew; Koeberl, Christian; Anderson, R. Scott; Ishman, Scott E.

    2011-06-01

    The Younger Dryas (YD) impact hypothesis is a recent theory that suggests that a cometary or meteoritic body or bodies hit and/or exploded over North America 12,900 years ago, causing the YD climate episode, extinction of Pleistocene megafauna, demise of the Clovis archeological culture, and a range of other effects. Since gaining widespread attention in 2007, substantial research has focused on testing the 12 main signatures presented as evidence of a catastrophic extraterrestrial event 12,900 years ago. Here we present a review of the impact hypothesis, including its evolution and current variants, and of efforts to test and corroborate the hypothesis. The physical evidence interpreted as signatures of an impact event can be separated into two groups. The first group consists of evidence that has been largely rejected by the scientific community and is no longer in widespread discussion, including: particle tracks in archeological chert; magnetic nodules in Pleistocene bones; impact origin of the Carolina Bays; and elevated concentrations of radioactivity, iridium, and fullerenes enriched in 3He. The second group consists of evidence that has been active in recent research and discussions: carbon spheres and elongates, magnetic grains and magnetic spherules, byproducts of catastrophic wildfire, and nanodiamonds. Over time, however, these signatures have also seen contrary evidence rather than support. Recent studies have shown that carbon spheres and elongates do not represent extraterrestrial carbon nor impact-induced megafires, but are indistinguishable from fungal sclerotia and arthropod fecal material that are a small but common component of many terrestrial deposits. Magnetic grains and spherules are heterogeneously distributed in sediments, but reported measurements of unique peaks in concentrations at the YD onset have yet to be reproduced. The magnetic grains are certainly just iron-rich detrital grains, whereas reported YD magnetic spherules are

  6. Cosmological Constant and the Final Anthropic Hypothesis

    OpenAIRE

    Cirkovic, Milan M.; Bostrom, Nick

    1999-01-01

    The influence of recent detections of a finite vacuum energy ("cosmological constant") on our formulation of anthropic conjectures, particularly the so-called Final Anthropic Principle is investigated. It is shown that non-zero vacuum energy implies the onset of a quasi-exponential expansion of our causally connected domain ("the universe") at some point in the future, a stage similar to the inflationary expansion at the very beginning of time. The transition to this future inflationary phase...

  7. Approaches to informed consent for hypothesis-testing and hypothesis-generating clinical genomics research.

    Science.gov (United States)

    Facio, Flavia M; Sapp, Julie C; Linn, Amy; Biesecker, Leslie G

    2012-10-10

    Massively-parallel sequencing (MPS) technologies create challenges for informed consent of research participants given the enormous scale of the data and the wide range of potential results. We propose that the consent process in these studies be based on whether they use MPS to test a hypothesis or to generate hypotheses. To demonstrate the differences in these approaches to informed consent, we describe the consent processes for two MPS studies. The purpose of our hypothesis-testing study is to elucidate the etiology of rare phenotypes using MPS. The purpose of our hypothesis-generating study is to test the feasibility of using MPS to generate clinical hypotheses, and to approach the return of results as an experimental manipulation. Issues to consider in both designs include: volume and nature of the potential results, primary versus secondary results, return of individual results, duty to warn, length of interaction, target population, and privacy and confidentiality. The categorization of MPS studies as hypothesis-testing versus hypothesis-generating can help to clarify the issue of so-called incidental or secondary results for the consent process, and aid the communication of the research goals to study participants.

  8. Learning-Related Changes in Adolescents' Neural Networks during Hypothesis-Generating and Hypothesis-Understanding Training

    Science.gov (United States)

    Lee, Jun-Ki; Kwon, Yongju

    2012-01-01

    Fourteen science high school students participated in this study, which investigated neural-network plasticity associated with hypothesis-generating and hypothesis-understanding in learning. The students were divided into two groups and participated in either hypothesis-generating or hypothesis-understanding type learning programs, which were…

  9. A double-integration hypothesis to explain ocean ecosystem response to climate forcing

    Science.gov (United States)

    Di Lorenzo, Emanuele; Ohman, Mark D.

    2013-01-01

    Long-term time series of marine ecological indicators often are characterized by large-amplitude state transitions that can persist for decades. Understanding the significance of these variations depends critically on the underlying hypotheses characterizing expected natural variability. Using a linear autoregressive model in combination with long-term zooplankton observations off the California coast, we show that cumulative integrations of white-noise atmospheric forcing can generate marine population responses that are characterized by strong transitions and prolonged apparent state changes. This model provides a baseline hypothesis for explaining ecosystem variability and for interpreting the significance of abrupt responses and climate change signatures in marine ecosystems. PMID:23341628

  10. Worldwide Report, Epidemiology, No. 327

    National Research Council Canada - National Science Library

    1983-01-01

    Partial Contents: Epidemiology, Human Diseases, Health, Malaria, AIDS, Homosexual Male, Medical Administration, Rabies, Tuberculosis, Encephalitis Statistics, Gastroenteritie, Mystery Diseases, Children, Epidemics...

  11. Global epidemiology of sporotrichosis.

    Science.gov (United States)

    Chakrabarti, Arunaloke; Bonifaz, Alexandro; Gutierrez-Galhardo, Maria Clara; Mochizuki, Takashi; Li, Shanshan

    2015-01-01

    Sporotrichosis is an endemic mycosis caused by the dimorphic fungus Sporothrix schenckii sensu lato. It has gained importance in recent years due to its worldwide prevalence, recognition of multiple cryptic species within the originally described species, and its distinctive ecology, distribution, and epidemiology across the globe. In this review, we describe the current knowledge of the taxonomy, ecology, prevalence, molecular epidemiology, and outbreaks due to S. schenckii sensu lato. Despite its omnipresence in the environment, this fungus has remarkably diverse modes of infection and distribution patterns across the world. We have delved into the nuances of how sporotrichosis is intimately linked to different forms of human activities, habitats, lifestyles, and environmental and zoonotic interactions. The purpose of this review is to stimulate discussion about the peculiarities of this unique fungal pathogen and increase the awareness of clinicians and microbiologists, especially in regions of high endemicity, to its emergence and evolving presentations and to kindle further research into understanding the unorthodox mechanisms by which this fungus afflicts different human populations. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  12. Clinical Epidemiology Of Stroke

    Directory of Open Access Journals (Sweden)

    Nagaraja D

    2005-01-01

    Full Text Available Stroke is a huge public health problem because of its high morbidity and disability. The epidemiology of stroke is of relevance to construct practical paradigms to tackle this major health issue in the community. Recent data have shown that about 72-86% of strokes are ischemic, 9-18% are due to hemorrhage (intracerebral of subarachnoid and the rest are undefined. The risk factors for stroke are multiple and combined. At present, stroke is no more considered as unavoidable and untreatable. It is an emergency and specialized units and teams improve outcome and lower costs. Death related to stroke is declining in many countries and in both sexes. This decrease in multifactorial. The detection and more effective treatment of hypertension may play an important factor, as well as the improved medical care and improvement in diagnostic procedures. While stroke incidence appears stable and stroke mortality is slowly declining, the absolute magnitude of stroke is likely to grow over the next 30 years. as the population ages, the absolute number of stroke victims and demands on healthcare and other support systems is likely to increase substantially in the future. Keeping this in perspective, this chapter shall focus on the epidemiology of stroke in the world and in Indian, in particular.

  13. Radiation epidemiology: concept, methodology and statistical resources

    International Nuclear Information System (INIS)

    Vasques, Monica H. Braga; Carneiro, Janete C. Gaburo; Sordi, Gian M.A.

    2008-01-01

    As radiation exposure is the main point of interest in radiation epidemiology, epidemiologists try to relate the risk of diseases (mainly the risk of cancer) to the different levels and patterns of humankind exposure to radiation. Statistics as a branch of mathematics is able to prove associations and infer causality. As many researches are object of methodological limits, mainly those related to both the insufficient size of the sample and descriptive analysis as well as the choice of methods and variables, this paper aims at describing firstly the main kinds of epidemiological studies. Secondly, it relates distributions and summary measures (central tendency measures, measures of dispersion and normal distributions) and hypothesis tests as well necessary for each study. It also discusses the most appropriate statistical resource to the epidemiological evaluation. Finally, the main aim of this study is both to elaborate a systematic review of the researches that have been already done in Brazil since 2000, focusing on the effects caused by the occupational exposures to ionizing radiation in order to establish positive associations between them and to analyze the risk related to the workers health. This paper has as its basis the Reports in Public Health (Public Health Books-CSP) from which several studies about the exposure effects to ionizing radiation and referred kinds of cancer (e.g.: leukemia, skin cancer, thyroid gland cancer and bone cancer) have been taken as object of analysis. The relevance of this study lies in the most applied methods of risk to establish positive associations in ionizing radiation, in the relation between workers' workplace and his health. (author)

  14. Alternatives to the linear risk hypothesis

    International Nuclear Information System (INIS)

    Craig, A.G.

    1976-01-01

    A theoretical argument is presented which suggests that in using the linear hypothesis for all values of LET the low dose risk is overestimated for low LET but that it is underestimated for very high LET. The argument is based upon the idea that cell lesions which do not lead to cell death may in fact lead to a malignant cell. Expressions for the Surviving Fraction and the Cancer Risk based on this argument are given. An advantage of this very general approach is that is expresses cell survival and cancer risk entirely in terms of the cell lesions and avoids the rather contentious argument as to how the average number of lesions should be related to the dose. (U.K.)

  15. Large numbers hypothesis. II - Electromagnetic radiation

    Science.gov (United States)

    Adams, P. J.

    1983-01-01

    This paper develops the theory of electromagnetic radiation in the units covariant formalism incorporating Dirac's large numbers hypothesis (LNH). A direct field-to-particle technique is used to obtain the photon propagation equation which explicitly involves the photon replication rate. This replication rate is fixed uniquely by requiring that the form of a free-photon distribution function be preserved, as required by the 2.7 K cosmic radiation. One finds that with this particular photon replication rate the units covariant formalism developed in Paper I actually predicts that the ratio of photon number to proton number in the universe varies as t to the 1/4, precisely in accord with LNH. The cosmological red-shift law is also derived and it is shown to differ considerably from the standard form of (nu)(R) - const.

  16. Artistic talent in dyslexia--a hypothesis.

    Science.gov (United States)

    Chakravarty, Ambar

    2009-10-01

    The present article hints at a curious neurocognitive phenomenon of development of artistic talents in some children with dyslexia. The article also takes note of the phenomenon of creating in the midst of language disability as observed in the lives of such creative people like Leonardo da Vinci and Albert Einstein who were most probably affected with developmental learning disorders. It has been hypothesised that a developmental delay in the dominant hemisphere most likely 'disinhibits' the non-dominant parietal lobe to unmask talents, artistic or otherwise, in some such individuals. The present hypothesis follows the phenomenon of paradoxical functional facilitation described earlier. It has been suggested that children with learning disorders be encouraged to develop such hidden talents to full capacity, rather than be subjected to overemphasising on the correction of the disturbed coded symbol operations, in remedial training.

  17. Tissue misrepair hypothesis for radiation carcinogenesis

    International Nuclear Information System (INIS)

    Kondo, Sohei

    1991-01-01

    Dose-response curves for chronic leukemia in A-bomb survivors and liver tumors in patients given Thorotrast (colloidal thorium dioxide) show large threshold effects. The existence of these threshold effects can be explained by the following hypothesis. A high dose of radiation causes a persistent wound in a cellrenewable tissue. Disorder of the injured cell society partly frees the component cells from territorial restraints on their proliferation, enabling them to continue development of their cellular functions toward advanced autonomy. This progression might be achieved by continued epigenetic and genetic changes as a result of occasional errors in the otherwise concerted healing action of various endogeneous factors recruited for tissue repair. Carcinogenesis is not simply a single-cell problem but a cell-society problem. Therefore, it is not warranted to estimate risk at low doses by linear extrapolation from cancer data at high doses without knowledge of the mechanism of radiation carcinogenesis. (author) 57 refs

  18. Statistical hypothesis tests of some micrometeorological observations

    International Nuclear Information System (INIS)

    SethuRaman, S.; Tichler, J.

    1977-01-01

    Chi-square goodness-of-fit is used to test the hypothesis that the medium scale of turbulence in the atmospheric surface layer is normally distributed. Coefficients of skewness and excess are computed from the data. If the data are not normal, these coefficients are used in Edgeworth's asymptotic expansion of Gram-Charlier series to determine an altrnate probability density function. The observed data are then compared with the modified probability densities and the new chi-square values computed.Seventy percent of the data analyzed was either normal or approximatley normal. The coefficient of skewness g 1 has a good correlation with the chi-square values. Events with vertical-barg 1 vertical-bar 1 vertical-bar<0.43 were approximately normal. Intermittency associated with the formation and breaking of internal gravity waves in surface-based inversions over water is thought to be the reason for the non-normality

  19. The hexagon hypothesis: Six disruptive scenarios.

    Science.gov (United States)

    Burtles, Jim

    2015-01-01

    This paper aims to bring a simple but effective and comprehensive approach to the development, delivery and monitoring of business continuity solutions. To ensure that the arguments and principles apply across the board, the paper sticks to basic underlying concepts rather than sophisticated interpretations. First, the paper explores what exactly people are defending themselves against. Secondly, the paper looks at how defences should be set up. Disruptive events tend to unfold in phases, each of which invites a particular style of protection, ranging from risk management through to business continuity to insurance cover. Their impact upon any business operation will fall into one of six basic scenarios. The hexagon hypothesis suggests that everyone should be prepared to deal with each of these six disruptive scenarios and it provides them with a useful benchmark for business continuity.

  20. Novae, supernovae, and the island universe hypothesis

    International Nuclear Information System (INIS)

    Van Den Bergh, S.

    1988-01-01

    Arguments in Curtis's (1917) paper related to the island universe hypothesis and the existence of novae in spiral nebulae are considered. It is noted that the maximum magnitude versus rate-of-decline relation for novae may be the best tool presently available for the calibration of the extragalactic distance scale. Light curve observations of six novae are used to determine a distance of 18.6 + or - 3.5 MPc to the Virgo cluster. Results suggest that Type Ia supernovae cannot easily be used as standard candles, and that Type II supernovae are unsuitable as distance indicators. Factors other than precursor mass are probably responsible for determining the ultimate fate of evolving stars. 83 references

  1. Extra dimensions hypothesis in high energy physics

    Directory of Open Access Journals (Sweden)

    Volobuev Igor

    2017-01-01

    Full Text Available We discuss the history of the extra dimensions hypothesis and the physics and phenomenology of models with large extra dimensions with an emphasis on the Randall- Sundrum (RS model with two branes. We argue that the Standard Model extension based on the RS model with two branes is phenomenologically acceptable only if the inter-brane distance is stabilized. Within such an extension of the Standard Model, we study the influence of the infinite Kaluza-Klein (KK towers of the bulk fields on collider processes. In particular, we discuss the modification of the scalar sector of the theory, the Higgs-radion mixing due to the coupling of the Higgs boson to the radion and its KK tower, and the experimental restrictions on the mass of the radion-dominated states.

  2. Multiple model cardinalized probability hypothesis density filter

    Science.gov (United States)

    Georgescu, Ramona; Willett, Peter

    2011-09-01

    The Probability Hypothesis Density (PHD) filter propagates the first-moment approximation to the multi-target Bayesian posterior distribution while the Cardinalized PHD (CPHD) filter propagates both the posterior likelihood of (an unlabeled) target state and the posterior probability mass function of the number of targets. Extensions of the PHD filter to the multiple model (MM) framework have been published and were implemented either with a Sequential Monte Carlo or a Gaussian Mixture approach. In this work, we introduce the multiple model version of the more elaborate CPHD filter. We present the derivation of the prediction and update steps of the MMCPHD particularized for the case of two target motion models and proceed to show that in the case of a single model, the new MMCPHD equations reduce to the original CPHD equations.

  3. On the immunostimulatory hypothesis of cancer

    Directory of Open Access Journals (Sweden)

    Juan Bruzzo

    2011-12-01

    Full Text Available There is a rather generalized belief that the worst possible outcome for the application of immunological therapies against cancer is a null effect on tumor growth. However, a significant body of evidence summarized in the immunostimulatory hypothesis of cancer suggests that, upon certain circumstances, the growth of incipient and established tumors can be accelerated rather than inhibited by the immune response supposedly mounted to limit tumor growth. In order to provide more compelling evidence of this proposition, we have explored the growth behavior characteristics of twelve murine tumors -most of them of spontaneous origin- arisen in the colony of our laboratory, in putatively immunized and control mice. Using classical immunization procedures, 8 out of 12 tumors were actually stimulated in "immunized" mice while the remaining 4 were neither inhibited nor stimulated. Further, even these apparently non-antigenic tumors could reveal some antigenicity if more stringent than classical immunization procedures were used. This possibility was suggested by the results obtained with one of these four apparently non-antigenic tumors: the LB lymphoma. In effect, upon these stringent immunization pretreatments, LB was slightly inhibited or stimulated, depending on the titer of the immune reaction mounted against the tumor, with higher titers rendering inhibition and lower titers rendering tumor stimulation. All the above results are consistent with the immunostimulatory hypothesis that entails the important therapeutic implications -contrary to the orthodoxy- that, anti-tumor vaccines may run a real risk of doing harm if the vaccine-induced immunity is too weak to move the reaction into the inhibitory part of the immune response curve and that, a slight and prolonged immunodepression -rather than an immunostimulation- might interfere with the progression of some tumors and thus be an aid to cytotoxic therapies.

  4. The Stress Acceleration Hypothesis of Nightmares

    Directory of Open Access Journals (Sweden)

    Tore Nielsen

    2017-06-01

    Full Text Available Adverse childhood experiences can deleteriously affect future physical and mental health, increasing risk for many illnesses, including psychiatric problems, sleep disorders, and, according to the present hypothesis, idiopathic nightmares. Much like post-traumatic nightmares, which are triggered by trauma and lead to recurrent emotional dreaming about the trauma, idiopathic nightmares are hypothesized to originate in early adverse experiences that lead in later life to the expression of early memories and emotions in dream content. Accordingly, the objectives of this paper are to (1 review existing literature on sleep, dreaming and nightmares in relation to early adverse experiences, drawing upon both empirical studies of dreaming and nightmares and books and chapters by recognized nightmare experts and (2 propose a new approach to explaining nightmares that is based upon the Stress Acceleration Hypothesis of mental illness. The latter stipulates that susceptibility to mental illness is increased by adversity occurring during a developmentally sensitive window for emotional maturation—the infantile amnesia period—that ends around age 3½. Early adversity accelerates the neural and behavioral maturation of emotional systems governing the expression, learning, and extinction of fear memories and may afford short-term adaptive value. But it also engenders long-term dysfunctional consequences including an increased risk for nightmares. Two mechanisms are proposed: (1 disruption of infantile amnesia allows normally forgotten early childhood memories to influence later emotions, cognitions and behavior, including the common expression of threats in nightmares; (2 alterations of normal emotion regulation processes of both waking and sleep lead to increased fear sensitivity and less effective fear extinction. These changes influence an affect network previously hypothesized to regulate fear extinction during REM sleep, disruption of which leads to

  5. Relación biogeográfica entre cangrejos dulceacuícolas y acociles a lo largo de la zona mexicana de transición: revaluación de la hipótesis de Rodríguez (1986 Biogeographic relationship of freshwater crabs and crayfish along the Mexican transition zone: reevaluating Rodríguez (1986 hypothesis

    Directory of Open Access Journals (Sweden)

    Fernando Álvarez

    2012-12-01

    Full Text Available A partir de la hipótesis planteada por Rodríguez (1986 sobre una posible exclusión biogeográfica entre acociles de la familia Cambaridae y cangrejos de agua dulce de la familia Pseudothelphusidae a lo largo del centro y sur de México, se han hecho varios estudios que toman en cuenta este patrón. Sin embargo, no se han examinado los patrones de distribución de estos grupos ni cuáles son las zonas ni a qué grado se da el traslape o contacto de las 2 distribuciones. Se construyeron 2 bases de datos, una con más de 1 400 registros de las especies de la familia Cambaridae y otra con más de 400 registros de cangrejos de la familia Pseudothelphusidae. Se construyeron mapas de distribución y se identificaron 3 regiones donde el contacto es evidente: el eje neovolcánico, la región de Los Tuxtlas, Veracruz y el estado de Chiapas. Los resultados muestran grandes zonas de contacto en las cuales tanto acociles como cangrejos pueden estar en la misma localidad y en el mismo cuerpo de agua o pueden estar en 2 localidades muy cercanas pero con una diferencia altitudinal. En general, los acociles tienden a distribuirse a mayores altitudes que los cangrejos. Aunado a los patrones de distribución, se discute que aunque los 2 grupos estén presentes en la misma localidad y en el mismo cuerpo de agua, el microhábitat que ocupa cada uno es distinto, por lo que se sugiere que la interferencia entre ellos será poca o nula.After Rodríguez (1986 hypothesis on the possible biogeographic exclusion between crayfish of the family Cambaridae and freshwater crabs of the family Pseudothelphusidae throughout central and southern Mexico, several studies have considered it as a real pattern. However, the distribution patterns of both groups have not been examined, nor in what areas and to what extent the overlap of the 2 distributions occurs. Two data bases were compiled, one with more than 1 400 records of the species of the family Cambaridae and a second one

  6. Phase transitions

    CERN Document Server

    Sole, Ricard V; Solé, Ricard V; Solé, Ricard V; Sol, Ricard V; Solé, Ricard V

    2011-01-01

    Phase transitions--changes between different states of organization in a complex system--have long helped to explain physics concepts, such as why water freezes into a solid or boils to become a gas. How might phase transitions shed light on important problems in biological and ecological complex systems? Exploring the origins and implications of sudden changes in nature and society, Phase Transitions examines different dynamical behaviors in a broad range of complex systems. Using a compelling set of examples, from gene networks and ant colonies to human language and the degradation of diverse ecosystems, the book illustrates the power of simple models to reveal how phase transitions occur. Introductory chapters provide the critical concepts and the simplest mathematical techniques required to study phase transitions. In a series of example-driven chapters, Ricard Solé shows how such concepts and techniques can be applied to the analysis and prediction of complex system behavior, including the origins of ...

  7. Epidemiological Transition of End-Stage Kidney Disease in Oman.

    Science.gov (United States)

    Al Ismaili, Faisal; Al Salmi, Issa; Al Maimani, Yaqoub; Metry, Abdul Massiah; Al Marhoobi, Humood; Hola, Alan; Pisoni, Ronald L

    2017-01-01

    The number of persons receiving renal replacement therapy (RRT) is estimated at more than 2.5 million worldwide, and is growing by 8% annually. Registries in the developing world are not up to standards compared to the United States Renal Data System (USRDS). Herein we examine the causes, progression, and magnitude of end-stage kidney disease (ESKD) over 3 decades in Oman. We examined ESKD data from 1983 to 2013. Data from 1998 to 2013 were obtained through an Information Management System. Data before 2008 were collected from patients' files. A questionnaire based on USRDS form 2728 was completed by nephrologists once a citizen reached ESKD. A total of 4066 forms were completed, with a response rate of 90% (52% male). The mean (SD) age was 50.1 (14.0) years. By 31 December 2013, there were 2386 patients alive on RRT, of whom 1206 were on hemodialysis (50.5%), 1080 were living with a functioning kidney transplant (45.3%), and 100 were receiving peritoneal dialysis (4.2%). The incidence of ESKD on RRT was 21, 75, and 120 per million population in 1983, 2001, and 2013, respectively. Similarly, the prevalence of ESKD was 49, 916, and 2386 in 1983, 2001, and 2013 respectively. Among patients with ESKD on RRT, a progressive rise was seen in diabetic nephropathy, with 5.8%, 32.1%, and 46% in 1983, 2001, and 2013 respectively. The incidence and prevalence of ESKD has increased progressively over last 30 years. This is anticipated to continue at an even higher rate in view of the progressive rise in noncommunicable diseases. Continuous improvement in registries is required to improve capturing of ESKD patients for providing accurate data to health authorities, and enhancing public awareness of the magnitude, future trends, treatments, and outcomes regarding ESKD.

  8. Epidemiological Transition of End-Stage Kidney Disease in Oman

    Directory of Open Access Journals (Sweden)

    Faisal Al Ismaili

    2017-01-01

    Discussion: The incidence and prevalence of ESKD has increased progressively over last 30 years. This is anticipated to continue at an even higher rate in view of the progressive rise in noncommunicable diseases. Continuous improvement in registries is required to improve capturing of ESKD patients for providing accurate data to health authorities, and enhancing public awareness of the magnitude, future trends, treatments, and outcomes regarding ESKD.

  9. Cancer Epidemiology Data Repository (CEDR)

    Science.gov (United States)

    In an effort to broaden access and facilitate efficient data sharing, the Epidemiology and Genomics Research Program (EGRP) has created the Cancer Epidemiology Data Repository (CEDR), a centralized, controlled-access database, where Investigators can deposit individual-level de-identified observational cancer datasets.

  10. CEDR: Comprehensive Epidemiologic Data Resource

    Energy Technology Data Exchange (ETDEWEB)

    1993-08-01

    The Department of Energy (DOE) and its predecessor agencies have a long history of epidemiologic research programs. The main focus of these programs has been the Health and Mortality Study of the DOE work force. This epidemiologic study began in 1964 with a feasibility study of workers at the Hanford facility. Studies of other populations exposed to radiation have also been supported, including the classic epidemiologic study of radium dial painters and studies of atomic bomb survivors. From a scientific perspective, these epidemiologic research program have been productive, highly credible, and formed the bases for many radiological protection standards. Recently, there has been concern that, although research results were available, the data on which these results were based were not easily obtained by interested investigators outside DOE. Therefore, as part of an effort to integrate and broaden access to its epidemiologic information, the DOE has developed the Comprehensive Epidemiologic Data Resource (CEDR) Program. Included in this effort is the development of a computer information system for accessing the collection of CEDR data and its related descriptive information. The epidemiologic data currently available through the CEDAR Program consist of analytic data sets, working data sets, and their associated documentation files. In general, data sets are the result of epidemiologic studies that have been conducted on various groups of workers at different DOE facilities during the past 30 years.

  11. Epidemiology of fibromyalgia.

    Science.gov (United States)

    Neumann, Lily; Buskila, Dan

    2003-10-01

    Chronic widespread pain, the cardinal symptom of fibromyalgia (FM), is common in the general population, with comparable prevalence rates of 7.3% to 12.9% across different countries. The prevalence of FM in the general population was reported to range from 0.5% to 5% and up to 15.7% in the clinic. The common association of FM with other rheumatic disorders, chronic viral infections, and systemic illnesses has been well documented in several studies. Up to 65% of patients with systemic lupus erythematosus meet the criteria for FM. FM is considered a member of the family of functional somatic syndromes. These syndromes are very common and share a similar phenomenology, epidemiologic characteristics, high rates of occurrence, a common pathogenesis, and similar management strategies. A high prevalence of FM was demonstrated among relatives of patients with FM and it may be attributed to genetic and environmental factors.

  12. [Epidemiology of osteoporosis].

    Science.gov (United States)

    Grazio, Simeon

    2006-01-01

    Osteoporosis represents a major and increasing public health problem with the aging of population. Major clinical consequences and economic burden of the disease are fractures. Many risk factors are associated with the fractures including low bone mass, hormonal disorders, personal and family history of fractures, low body weight, use of certain drugs (e.g. glucocorticoids), cigarette smoking, elevated intake of alchohol, low physical activity, insufficient level of vitamin D and low intake of calcium. This epidemiological review describes frequency, importance of risk factors and impact of osteoporosis and osteoporotic fractures. Objective measures of bone mineral density along with clinical assessment of risk factors can help identify patients who will benefit from prevention and intervention efforts and eventually reduce the morbidity and mortality associated with osteoporosis-related fractures.

  13. Temporal network epidemiology

    CERN Document Server

    Holme, Petter

    2017-01-01

    This book covers recent developments in epidemic process models and related data on temporally varying networks. It is widely recognized that contact networks are indispensable for describing, understanding, and intervening to stop the spread of infectious diseases in human and animal populations; “network epidemiology” is an umbrella term to describe this research field. More recently, contact networks have been recognized as being highly dynamic. This observation, also supported by an increasing amount of new data, has led to research on temporal networks, a rapidly growing area. Changes in network structure are often informed by epidemic (or other) dynamics, in which case they are referred to as adaptive networks. This volume gathers contributions by prominent authors working in temporal and adaptive network epidemiology, a field essential to understanding infectious diseases in real society.

  14. [Ethics and epidemiology].

    Science.gov (United States)

    Barata, Rita Barradas

    2005-01-01

    Human actions take place at the confluence of circumstances that require us to discern the proper way to act. Ethics falls within the terrain of practical knowledge, of knowledge about what is contingent. It belongs to the domain of moral judgments or value judgments. The counterpart of disenchantment with our contemporary world lies in an effort to re-establish an interest in ethics. There are basically three orders of relations between public health and human rights: the quest for balance between the collective good and individual rights; methods and techniques for identifying human rights violations and assessing their negative impact; and the tie between protecting individual rights and promoting health. The relationship between ethics and epidemiology goes beyond the ethical aspects involving research on human beings to encompass political commitments, practices within health services, and the production of knowledge.

  15. The Epidemiology of Sarcoma

    Directory of Open Access Journals (Sweden)

    Burningham Zachary

    2012-10-01

    Full Text Available Abstract Sarcomas account for over 20% of all pediatric solid malignant cancers and less than 1% of all adult solid malignant cancers. The vast majority of diagnosed sarcomas will be soft tissue sarcomas, while malignant bone tumors make up just over 10% of sarcomas. The risks for sarcoma are not well-understood. We evaluated the existing literature on the epidemiology and etiology of sarcoma. Risks for sarcoma development can be divided into environmental exposures, genetic susceptibility, and an interaction between the two. HIV-positive individuals are at an increased risk for Kaposi’s sarcoma, even though HHV8 is the causative virus. Radiation exposure from radiotherapy has been strongly associated with secondary sarcoma development in certain cancer patients. In fact, the risk of malignant bone tumors increases as the cumulative dose of radiation to the bone increases (p for trend

  16. Epidemiology of Lyme Disease

    Directory of Open Access Journals (Sweden)

    Dennis J White

    1991-01-01

    Full Text Available Investigation of the epidemiology of Lyme disease depends upon information generated from several sources. Human disease surveillance can be conducted by both passive and active means involving physicians, public health agencies and laboratories. Passive and active tick surveillance programs can document the extent of tick-borne activity, identify the geographic range of potential vector species, and determine the relative risk of exposure to Lyme disease in specific areas. Standardized laboratory services can play an important role in providing data. Epidemiologists can gain a better understanding of Lyme disease through the collection of data from such programs. The interpretation of data and provision of information to the medical and general communities are important functions of public health agencies.

  17. Cation dyshomeostasis and cardiomyocyte necrosis: the Fleckenstein hypothesis revisited

    Science.gov (United States)

    Borkowski, Brian J.; Cheema, Yaser; Shahbaz, Atta U.; Bhattacharya, Syamal K.; Weber, Karl T.

    2011-01-01

    An ongoing loss of cardiomyocytes to apoptotic and necrotic cell death pathways contributes to the progressive nature of heart failure. The pathophysiological origins of necrotic cell loss relate to the neurohormonal activation that accompanies acute and chronic stressor states and which includes effector hormones of the adrenergic nervous system. Fifty years ago, Albrecht Fleckenstein and coworkers hypothesized the hyperadrenergic state, which accompanies such stressors, causes cardiomyocyte necrosis based on catecholamine-initiated excessive intracellular Ca2+ accumulation (EICA), and mitochondrial Ca2+ overloading in particular, in which the ensuing dysfunction and structural degeneration of these organelles leads to necrosis. In recent years, two downstream factors have been identified which, together with EICA, constitute a signal–transducer–effector pathway: (i) mitochondria-based induction of oxidative stress, in which the rate of reactive oxygen metabolite generation exceeds their rate of detoxification by endogenous antioxidant defences; and (ii) the opening of the mitochondrial inner membrane permeability transition pore (mPTP) followed by organellar swelling and degeneration. The pathogenesis of stress-related cardiomyopathy syndromes is likely related to this pathway. Other factors which can account for cytotoxicity in stressor states include: hypokalaemia; ionized hypocalcaemia and hypomagnesaemia with resultant elevations in parathyroid hormone serving as a potent mediator of EICA; and hypozincaemia with hyposelenaemia, which compromise antioxidant defences. Herein, we revisit the Fleckenstein hypothesis of EICA in leading to cardiomyocyte necrosis and the central role played by mitochondria. PMID:21398641

  18. Muon capture on Ni isotopes, projected QRPA, and CVC hypothesis

    International Nuclear Information System (INIS)

    Samana, Arturo R.; Sande, Danilo; Krmpotic, Francisco; Universidad Nacional de La Plata

    2011-01-01

    In recent years we have developed a novel formalism for the weak interaction processes, obtaining new expressions for the transition rates, which greatly facilitate numerical calculations, for both neutrino-nucleus reactions and muon capture, allowing us to use very large configuration spaces and to evaluate the quasielastic 12 C (ν, μ - ) 12 N cross section at energies of the order of 1 GeV, which are measured in the MiniBooNE experiment. Our formulation includes for the first time the consequences of the explicit violation of the conserved vector current (CVC) hypothesis by the Coulomb field. We have also shown that the particle number projection procedure within the quasiparticle random phase approximation (QRPA) is important in describing the exclusive (ground-state) properties of 12 B and 12 N as well as the muon capture rate and the neutrino nucleus cross section in 56 Fe. In this work, we analyze in a quantitative way the consequences of the CVC violation on the muon capture rates in Ni isotopes (for which are available the experimental data) using both the standard QRPA and the projected QRPA (PQRPA). The last one is the only RPA model that treats the Pauli Principle correctly, and we demonstrate that the number projection procedure is important not only for light nuclei but also for medium heavy ones that were studied here. (author)

  19. The Matter-Gravity Entanglement Hypothesis

    Science.gov (United States)

    Kay, Bernard S.

    2018-03-01

    I outline some of my work and results (some dating back to 1998, some more recent) on my matter-gravity entanglement hypothesis, according to which the entropy of a closed quantum gravitational system is equal to the system's matter-gravity entanglement entropy. The main arguments presented are: (1) that this hypothesis is capable of resolving what I call the second-law puzzle, i.e. the puzzle as to how the entropy increase of a closed system can be reconciled with the asssumption of unitary time-evolution; (2) that the black hole information loss puzzle may be regarded as a special case of this second law puzzle and that therefore the same resolution applies to it; (3) that the black hole thermal atmosphere puzzle (which I recall) can be resolved by adopting a radically different-from-usual description of quantum black hole equilibrium states, according to which they are total pure states, entangled between matter and gravity in such a way that the partial states of matter and gravity are each approximately thermal equilibrium states (at the Hawking temperature); (4) that the Susskind-Horowitz-Polchinski string-theoretic understanding of black hole entropy as the logarithm of the degeneracy of a long string (which is the weak string coupling limit of a black hole) cannot be quite correct but should be replaced by a modified understanding according to which it is the entanglement entropy between a long string and its stringy atmosphere, when in a total pure equilibrium state in a suitable box, which (in line with (3)) goes over, at strong-coupling, to a black hole in equilibrium with its thermal atmosphere. The modified understanding in (4) is based on a general result, which I also describe, which concerns the likely state of a quantum system when it is weakly coupled to an energy-bath and the total state is a random pure state with a given energy. This result generalizes Goldstein et al.'s `canonical typicality' result to systems which are not necessarily small.

  20. The Matter-Gravity Entanglement Hypothesis

    Science.gov (United States)

    Kay, Bernard S.

    2018-05-01

    I outline some of my work and results (some dating back to 1998, some more recent) on my matter-gravity entanglement hypothesis, according to which the entropy of a closed quantum gravitational system is equal to the system's matter-gravity entanglement entropy. The main arguments presented are: (1) that this hypothesis is capable of resolving what I call the second-law puzzle, i.e. the puzzle as to how the entropy increase of a closed system can be reconciled with the asssumption of unitary time-evolution; (2) that the black hole information loss puzzle may be regarded as a special case of this second law puzzle and that therefore the same resolution applies to it; (3) that the black hole thermal atmosphere puzzle (which I recall) can be resolved by adopting a radically different-from-usual description of quantum black hole equilibrium states, according to which they are total pure states, entangled between matter and gravity in such a way that the partial states of matter and gravity are each approximately thermal equilibrium states (at the Hawking temperature); (4) that the Susskind-Horowitz-Polchinski string-theoretic understanding of black hole entropy as the logarithm of the degeneracy of a long string (which is the weak string coupling limit of a black hole) cannot be quite correct but should be replaced by a modified understanding according to which it is the entanglement entropy between a long string and its stringy atmosphere, when in a total pure equilibrium state in a suitable box, which (in line with (3)) goes over, at strong-coupling, to a black hole in equilibrium with its thermal atmosphere. The modified understanding in (4) is based on a general result, which I also describe, which concerns the likely state of a quantum system when it is weakly coupled to an energy-bath and the total state is a random pure state with a given energy. This result generalizes Goldstein et al.'s `canonical typicality' result to systems which are not necessarily small.

  1. Participatory epidemiology: the contribution of participatory research to epidemiology

    Directory of Open Access Journals (Sweden)

    Mario Bach

    2017-02-01

    Full Text Available Abstract Background Epidemiology has contributed in many ways to identifying various risk factors for disease and to promoting population health. However, there is a continuing debate about the ability of epidemiology not only to describe, but also to provide results which can be better translated into public health practice. It has been proposed that participatory research approaches be applied to epidemiology as a way to bridge this gap between description and action. A systematic account of what constitutes participatory epidemiology practice has, however, been lacking. Methods A scoping review was carried out focused on the question of what constitutes participatory approaches to epidemiology for the purpose of demonstrating their potential for advancing epidemiologic research. Relevant databases were searched, including both the published and non-published (grey literature. The 102 identified sources were analyzed in terms of comparing common epidemiologic approaches to participatory counterparts regarding central aspects of the research process. Exemplary studies applying participatory approaches were examined more closely. Results A highly diverse, interdisciplinary body of literature was synthesized, resulting in a framework comprised of seven aspects of the research process: research goal, research question, population, context, data synthesis, research management, and dissemination of findings. The framework specifies how participatory approaches not only differ from, but also how they can enhance common approaches in epidemiology. Finally, recommendations for the further development of participatory approaches are given. These include: enhancing data collection, data analysis, and data validation; advancing capacity building for research at the local level; and developing data synthesis. Conclusion The proposed framework provides a basis for systematically developing the emergent science of participatory epidemiology.

  2. Hypothesis test for synchronization: twin surrogates revisited.

    Science.gov (United States)

    Romano, M Carmen; Thiel, Marco; Kurths, Jürgen; Mergenthaler, Konstantin; Engbert, Ralf

    2009-03-01

    The method of twin surrogates has been introduced to test for phase synchronization of complex systems in the case of passive experiments. In this paper we derive new analytical expressions for the number of twins depending on the size of the neighborhood, as well as on the length of the trajectory. This allows us to determine the optimal parameters for the generation of twin surrogates. Furthermore, we determine the quality of the twin surrogates with respect to several linear and nonlinear statistics depending on the parameters of the method. In the second part of the paper we perform a hypothesis test for phase synchronization in the case of experimental data from fixational eye movements. These miniature eye movements have been shown to play a central role in neural information processing underlying the perception of static visual scenes. The high number of data sets (21 subjects and 30 trials per person) allows us to compare the generated twin surrogates with the "natural" surrogates that correspond to the different trials. We show that the generated twin surrogates reproduce very well all linear and nonlinear characteristics of the underlying experimental system. The synchronization analysis of fixational eye movements by means of twin surrogates reveals that the synchronization between the left and right eye is significant, indicating that either the centers in the brain stem generating fixational eye movements are closely linked, or, alternatively that there is only one center controlling both eyes.

  3. Marginal contrasts and the Contrastivist Hypothesis

    Directory of Open Access Journals (Sweden)

    Daniel Currie Hall

    2016-12-01

    Full Text Available The Contrastivist Hypothesis (CH; Hall 2007; Dresher 2009 holds that the only features that can be phonologically active in any language are those that serve to distinguish phonemes, which presupposes that phonemic status is categorical. Many researchers, however, demonstrate the existence of gradient relations. For instance, Hall (2009 quantifies these using the information-theoretic measure of entropy (unpredictability of distribution and shows that a pair of sounds may have an entropy between 0 (totally predictable and 1 (totally unpredictable. We argue that the existence of such intermediate degrees of contrastiveness does not make the CH untenable, but rather offers insight into contrastive hierarchies. The existence of a continuum does not preclude categorical distinctions: a categorical line can be drawn between zero entropy (entirely predictable, and thus by the CH phonologically inactive and non-zero entropy (at least partially contrastive, and thus potentially phonologically active. But this does not mean that intermediate degrees of surface contrastiveness are entirely irrelevant to the CH; rather, we argue, they can shed light on how deeply ingrained a phonemic distinction is in the phonological system. As an example, we provide a case study from Pulaar [ATR] harmony, which has previously been claimed to be problematic for the CH.

  4. The Stem Cell Hypothesis of Aging

    Directory of Open Access Journals (Sweden)

    Anna Meiliana

    2010-04-01

    Full Text Available BACKGROUND: There is probably no single way to age. Indeed, so far there is no single accepted explanation or mechanisms of aging (although more than 300 theories have been proposed. There is an overall decline in tissue regenerative potential with age, and the question arises as to whether this is due to the intrinsic aging of stem cells or rather to the impairment of stem cell function in the aged tissue environment. CONTENT: Recent data suggest that we age, in part, because our self-renewing stem cells grow old as a result of heritable intrinsic events, such as DNA damage, as well as extrinsic forces, such as changes in their supporting niches. Mechanisms that suppress the development of cancer, such as senescence and apoptosis, which rely on telomere shortening and the activities of p53 and p16INK4a may also induce an unwanted consequence: a decline in the replicative function of certain stem cells types with advancing age. This decrease regenerative capacity appears to pointing to the stem cell hypothesis of aging. SUMMARY: Recent evidence suggested that we grow old partly because of our stem cells grow old as a result of mechanisms that suppress the development of cancer over a lifetime. We believe that a further, more precise mechanistic understanding of this process will be required before this knowledge can be translated into human anti-aging therapies. KEYWORDS: stem cells, senescence, telomere, DNA damage, epigenetic, aging.

  5. Confabulation: Developing the 'emotion dysregulation' hypothesis.

    Science.gov (United States)

    Turnbull, Oliver H; Salas, Christian E

    2017-02-01

    Confabulations offer unique opportunities for establishing the neurobiological basis of delusional thinking. As regards causal factors, a review of the confabulation literature suggests that neither amnesia nor executive impairment can be the sole (or perhaps even the primary) cause of all delusional beliefs - though they may act in concert with other factors. A key perspective in the modern literature is that many delusions have an emotionally positive or 'wishful' element, that may serve to modulate or manage emotional experience. Some authors have referred to this perspective as the 'emotion dysregulation' hypothesis. In this article we review the theoretical underpinnings of this approach, and develop the idea by suggesting that the positive aspects of confabulatory states may have a role in perpetuating the imbalance between cognitive control and emotion. We draw on existing evidence from fields outside neuropsychology, to argue for three main causal factors: that positive emotions are related to more global or schematic forms of cognitive processing; that positive emotions influence the accuracy of memory recollection; and that positive emotions make people more susceptible to false memories. These findings suggest that the emotions that we want to feel (or do not want to feel) can influence the way we reconstruct past experiences and generate a sense of self - a proposition that bears on a unified theory of delusional belief states. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  6. Evolutionary hypothesis for Chiari type I malformation.

    Science.gov (United States)

    Fernandes, Yvens Barbosa; Ramina, Ricardo; Campos-Herrera, Cynthia Resende; Borges, Guilherme

    2013-10-01

    Chiari I malformation (CM-I) is classically defined as a cerebellar tonsillar herniation (≥5 mm) through the foramen magnum. A decreased posterior fossa volume, mainly due to basioccipital hypoplasia and sometimes platybasia, leads to posterior fossa overcrowding and consequently cerebellar herniation. Regardless of radiological findings, embryological genetic hypothesis or any other postulations, the real cause behind this malformation is yet not well-elucidated and remains largely unknown. The aim of this paper is to approach CM-I under a broader and new perspective, conjoining anthropology, genetics and neurosurgery, with special focus on the substantial changes that have occurred in the posterior cranial base through human evolution. Important evolutionary allometric changes occurred during brain expansion and genetics studies of human evolution demonstrated an unexpected high rate of gene flow interchange and possibly interbreeding during this process. Based upon this review we hypothesize that CM-I may be the result of an evolutionary anthropological imprint, caused by evolving species populations that eventually met each other and mingled in the last 1.7 million years. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Environmental Kuznets Curve Hypothesis. A Survey

    International Nuclear Information System (INIS)

    Dinda, Soumyananda

    2004-01-01

    The Environmental Kuznets Curve (EKC) hypothesis postulates an inverted-U-shaped relationship between different pollutants and per capita income, i.e., environmental pressure increases up to a certain level as income goes up; after that, it decreases. An EKC actually reveals how a technically specified measurement of environmental quality changes as the fortunes of a country change. A sizeable literature on EKC has grown in recent period. The common point of all the studies is the assertion that the environmental quality deteriorates at the early stages of economic development/growth and subsequently improves at the later stages. In other words, environmental pressure increases faster than income at early stages of development and slows down relative to GDP growth at higher income levels. This paper reviews some theoretical developments and empirical studies dealing with EKC phenomenon. Possible explanations for this EKC are seen in (1) the progress of economic development, from clean agrarian economy to polluting industrial economy to clean service economy; (2) tendency of people with higher income having higher preference for environmental quality, etc. Evidence of the existence of the EKC has been questioned from several corners. Only some air quality indicators, especially local pollutants, show the evidence of an EKC. However, an EKC is empirically observed, till there is no agreement in the literature on the income level at which environmental degradation starts declining. This paper provides an overview of the EKC literature, background history, conceptual insights, policy and the conceptual and methodological critique

  8. DAMPs, ageing, and cancer: The 'DAMP Hypothesis'.

    Science.gov (United States)

    Huang, Jin; Xie, Yangchun; Sun, Xiaofang; Zeh, Herbert J; Kang, Rui; Lotze, Michael T; Tang, Daolin

    2015-11-01

    Ageing is a complex and multifactorial process characterized by the accumulation of many forms of damage at the molecular, cellular, and tissue level with advancing age. Ageing increases the risk of the onset of chronic inflammation-associated diseases such as cancer, diabetes, stroke, and neurodegenerative disease. In particular, ageing and cancer share some common origins and hallmarks such as genomic instability, epigenetic alteration, aberrant telomeres, inflammation and immune injury, reprogrammed metabolism, and degradation system impairment (including within the ubiquitin-proteasome system and the autophagic machinery). Recent advances indicate that damage-associated molecular pattern molecules (DAMPs) such as high mobility group box 1, histones, S100, and heat shock proteins play location-dependent roles inside and outside the cell. These provide interaction platforms at molecular levels linked to common hallmarks of ageing and cancer. They can act as inducers, sensors, and mediators of stress through individual plasma membrane receptors, intracellular recognition receptors (e.g., advanced glycosylation end product-specific receptors, AIM2-like receptors, RIG-I-like receptors, and NOD1-like receptors, and toll-like receptors), or following endocytic uptake. Thus, the DAMP Hypothesis is novel and complements other theories that explain the features of ageing. DAMPs represent ideal biomarkers of ageing and provide an attractive target for interventions in ageing and age-associated diseases. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Identity of Particles and Continuum Hypothesis

    Science.gov (United States)

    Berezin, Alexander A.

    2001-04-01

    Why all electrons are the same? Unlike other objects, particles and atoms (same isotopes) are forbidden to have individuality or personal history (or reveal their hidden variables, even if they do have them). Or at least, what we commonly call physics so far was unable to disprove particle's sameness (Berezin and Nakhmanson, Physics Essays, 1990). Consider two opposing hypotheses: (A) particles are indeed absolutely same, or (B) they do have individuality, but it is beyond our capacity to demonstrate. This dilemma sounds akin to undecidability of Continuum Hypothesis of existence (or not) of intermediate cardinalities between integers and reals (P.Cohen). Both yes and no of it are true. Thus, (alleged) sameness of electrons and atoms may be a physical translation (embodiment) of this fundamental Goedelian undecidability. Experiments unlikely to help: even if we find that all electrons are same within 30 decimal digits, could their masses (or charges) still differ in100-th digit? Within (B) personalized informationally rich (infinitely rich?) digital tails (starting at, say, 100-th decimal) may carry individual record of each particle history. Within (A) parameters (m, q) are indeed exactly same in all digits and their sameness is based on some inherent (meta)physical principle akin to Platonism or Eddington-type numerology.

  10. Environmental Kuznets Curve Hypothesis. A Survey

    Energy Technology Data Exchange (ETDEWEB)

    Dinda, Soumyananda [Economic Research Unit, Indian Statistical Institute, 203, B.T. Road, Kolkata-108 (India)

    2004-08-01

    The Environmental Kuznets Curve (EKC) hypothesis postulates an inverted-U-shaped relationship between different pollutants and per capita income, i.e., environmental pressure increases up to a certain level as income goes up; after that, it decreases. An EKC actually reveals how a technically specified measurement of environmental quality changes as the fortunes of a country change. A sizeable literature on EKC has grown in recent period. The common point of all the studies is the assertion that the environmental quality deteriorates at the early stages of economic development/growth and subsequently improves at the later stages. In other words, environmental pressure increases faster than income at early stages of development and slows down relative to GDP growth at higher income levels. This paper reviews some theoretical developments and empirical studies dealing with EKC phenomenon. Possible explanations for this EKC are seen in (1) the progress of economic development, from clean agrarian economy to polluting industrial economy to clean service economy; (2) tendency of people with higher income having higher preference for environmental quality, etc. Evidence of the existence of the EKC has been questioned from several corners. Only some air quality indicators, especially local pollutants, show the evidence of an EKC. However, an EKC is empirically observed, till there is no agreement in the literature on the income level at which environmental degradation starts declining. This paper provides an overview of the EKC literature, background history, conceptual insights, policy and the conceptual and methodological critique.

  11. Transit transparency.

    Science.gov (United States)

    2012-07-01

    Public transit agencies have employed intelligent systems for determining : schedules and routes and for monitoring the real-time location and status of their : vehicle fleets for nearly two decades. But until recently, the data generated by : daily ...

  12. Research on chronic noncommunicable diseases in Brazil: meeting the challenges of epidemiologic transition Investigación sobre las enfermedades crónicas no transmisibles en el Brasil: responder a los retos de la transición epidemiológica

    Directory of Open Access Journals (Sweden)

    Erly C. Moura

    2012-03-01

    Full Text Available In Brazil, chronic noncommunicable diseases (CNCDs are the leading cause of death and a major contributor to the national disease burden. This article describes CNCD research funded by the Ministry of Health Department of Science and Technology (DECIT to support the production and dissemination of scientific evidence for the national health system, in accordance with the National Agenda of Priorities in Health Research, and within the context of Brazil's epidemiologic transition. Data were obtained from Ministry of Health database management systems. CNCD-related projects financed by DECIT from 2002 to 2009 were analyzed by research theme (cancer, obesity, hypertension, diabetes, cardiovascular diseases, CNCDs in general, and CNCD risk factors and geographic region. In terms of funding and number of projects, the most-supported research theme was cancer, and the most-supported region was the Southeast. Project type varied widely, ranging from basic scientific studies to highly technological research and development. Results obtained included epidemiologic profiles and surveillance, cost, and quality-of-life data.En el Brasil, las enfermedades crónicas no transmisibles (ECNT son la principal causa de mortalidad y un factor contribuyente muy importante a la carga de morbilidad nacional. En este artículo se describe la investigación en ECNT financiada por el Departamento de Ciencia y Tecnología del Ministerio de Salud (DECIT para apoyar la producción y la difusión de información científica destinada al sistema nacional de salud, en conformidad con el Programa Nacional de Prioridades en Investigación de Salud y dentro del contexto de la transición epidemiológica del Brasil. Los datos se obtuvieron a partir de los sistemas de manejo de bases de datos del Ministerio de Salud. Los proyectos relacionados con las ECNT financiados por el DECIT entre el 2002 y el 2009 fueron analizados por tema de investigación (cáncer, obesidad, hipertensi

  13. A NONPARAMETRIC HYPOTHESIS TEST VIA THE BOOTSTRAP RESAMPLING

    OpenAIRE

    Temel, Tugrul T.

    2001-01-01

    This paper adapts an already existing nonparametric hypothesis test to the bootstrap framework. The test utilizes the nonparametric kernel regression method to estimate a measure of distance between the models stated under the null hypothesis. The bootstraped version of the test allows to approximate errors involved in the asymptotic hypothesis test. The paper also develops a Mathematica Code for the test algorithm.

  14. The epidemiology of endometriosis.

    Science.gov (United States)

    Cramer, Daniel W; Missmer, Stacey A

    2002-03-01

    Advances in understanding the epidemiology of endometriosis have lagged behind other diseases because of methodologic problems related to disease definition and control selection. Nevertheless, a better picture of the epidemiology of endometriosis has emerged over the past few decades. Prevalence estimates of the disease in clinic populations vary from about a 4% occurrence of largely asymptomatic endometriosis found in women undergoing tubal ligation to 50% of teenagers with intractable dysmenorrhea. General population incidence during the 1970s in this country has been suggested to be 1.6 per 1000 white females aged 15-49, while a more current study based upon hospital discharges finds endometriosis as a first listed diagnosis in 1.3 per 1000 discharges in women aged 15-44. There is a clinical impression that blacks have lower rates of endometriosis and Orientals have higher rates than whites. A variety of personal risk factors for endometriosis have also been described. Women with endometriosis may be taller and thinner. Menstrual factors reported to increase risk include dysmenorrhea, early menarche, and shorter cycle lengths. There is support for the idea that lifestyle exposures that might raise or lower estrogen levels could affect risk, including a decreased risk associated with smoking and exercise and an increased risk associated with caffeine or alcohol use. These risk factors appear to be compatible with the central importance of retrograde menstruation influenced by outflow obstruction that might affect its amount, immune factors that might affect its ability to be cleared, or hormonal stimuli that might affect its growth. In this model, dysmenorrhea could be either a disease symptom or a manifestation of outflow obstruction. Nulliparity could be either a consequence of disease or a cause since nulliparous women would not have the benefit of cervical dilation associated with labor and delivery. Since there is evidence that family history is a risk

  15. [Psychodynamic hypothesis about suicidality in elderly men].

    Science.gov (United States)

    Lindner, Reinhard

    2010-08-01

    Old men are overrepresented in the whole of all suicides. In contrast, only very few elderly men find their way to specialised treatment facilities. Elderly accept psychotherapy more rarely than younger persons. Therefore presentations on the psychodynamics of suicidality in old men are rare and mostly casuistical. By means of a stepwise reconstructable qualitative case comparison of five randomly chosen elderly suicidal men with ideal types of suicidal (younger) men concerning biography, suicidal symptoms and transference, psychodynamic hypothesis of suicidality in elderly men are developed. All patients came into psychotherapy in a specialised academic out-patient clinic for psychodynamic treatment of acute and chronic suicidality. The five elderly suicidal men predominantly were living in long-term, conflictuous sexual relationships and also had ambivalent relationships to their children. Suicidality in old age refers to lifelong existing intrapsychic conflicts, concerning (male) identity, self-esteem and a core conflict between fusion and separation wishes. The body gets a central role in suicidal experiences, being a defensive instance modified by age and/or physical illness, which brings up to consciousness aggressive and envious impulses, but also feelings of emptiness and insecurity, which have to be warded off again by projection into the body. In transference relationships there are on the one hand the regular transference, on the other hand an age specific turned around transference, with their counter transference reactions. The chosen methodological approach serves the systematic finding of hypotheses with a higher degree in evidence than hypotheses generated from single case studies. Georg Thieme Verlag KG Stuttgart - New York.

  16. Atopic dermatitis and the hygiene hypothesis revisited.

    Science.gov (United States)

    Flohr, Carsten; Yeo, Lindsey

    2011-01-01

    We published a systematic review on atopic dermatitis (AD) and the hygiene hypothesis in 2005. Since then, the body of literature has grown significantly. We therefore repeated our systematic review to examine the evidence from population-based studies for an association between AD risk and specific infections, childhood immunizations, the use of antibiotics and environmental exposures that lead to a change in microbial burden. Medline was searched from 1966 until June 2010 to identify relevant studies. We found an additional 49 papers suitable for inclusion. There is evidence to support an inverse relationship between AD and endotoxin, early day care, farm animal and dog exposure in early life. Cat exposure in the presence of skin barrier impairment is positively associated with AD. Helminth infection at least partially protects against AD. This is not the case for viral and bacterial infections, but consumption of unpasteurized farm milk seems protective. Routine childhood vaccinations have no effect on AD risk. The positive association between viral infections and AD found in some studies appears confounded by antibiotic prescription, which has been consistently associated with an increase in AD risk. There is convincing evidence for an inverse relationship between helminth infections and AD but no other pathogens. The protective effect seen with early day care, endotoxin, unpasteurized farm milk and animal exposure is likely to be due to a general increase in exposure to non-pathogenic microbes. This would also explain the risk increase associated with the use of broad-spectrum antibiotics. Future studies should assess skin barrier gene mutation carriage and phenotypic skin barrier impairment, as gene-environment interactions are likely to impact on AD risk. Copyright © 041_ S. Karger AG, Basel.

  17. The Epidemiology of Obesity: A Big Picture

    Science.gov (United States)

    Hruby, Adela; Hu, Frank B.

    2016-01-01

    The epidemic of overweight and obesity presents a major challenge to chronic disease prevention and health across the life course around the world. Fueled by economic growth, industrialization, mechanized transport, urbanization, an increasingly sedentary lifestyle, and a nutritional transition to processed foods and high calorie diets over the last 30 years, many countries have witnessed the prevalence of obesity in its citizens double, and even quadruple. Rising prevalence of childhood obesity, in particular, forebodes a staggering burden of disease in individuals and healthcare systems in the decades to come. A complex, multifactorial disease, with genetic, behavioral, socioeconomic, and environmental origins, obesity raises risk of debilitating morbidity and mortality. Relying primarily on epidemiologic evidence published within the last decade, this non-exhaustive review discusses the extent of the obesity epidemic, its risk factors—known and novel—, sequelae, and economic impact across the globe. PMID:25471927

  18. Difficulty in Assessing Quality of Life Outcomes in a Fluctuating Disease: A Hypothesis Based on Gastroparesis

    Directory of Open Access Journals (Sweden)

    Vic Velanovich

    2009-01-01

    Full Text Available An underlying assumption of quality of life outcome research is that after some intervention a “steady-state” of quality of life is reached which can be identified as an endpoint, and, hence, the “outcome.” However, in some disease processes, no so such steady-state is reached. The hypothesis presented is that a disease process with a waxing and waning course will make it difficult to determine a quality of life endpoint. After clinical observation, a pilot study of patients with either diabetic or idiopathic gastroparesis with gastric neurostimulation their records were reviewed to identify the number of clinic visits, the number of clinic visits in which the patients were asymptomatic, much improved, improved, no change, worse, or much worse. These changes were defined as “transitions.” A “transition ratio” was calculated by dividing the number of transitions by the number of clinic visits. Preliminary results showed that of 32 patients, the median number of clinic encounters was 8 (1–35, and the median number of transitions 4 (0–22. The average transition ration was 0.56±0.31. In the case of gastroparesis, over half of all clinical encounters were associated with a transition. The implication of the hypothesis and preliminary finding suggests a difficulty to identify when the symptomatic endpoint was reached. Other methods to assess the effects of treatment in such a disease process are required to fully understand the effects of treatment on quality of life.

  19. Epidemiology of prostatitis

    Science.gov (United States)

    Krieger, John N.; Lee, Shaun Wen Huey; Jeon, Jeonseong; Cheah, Phaik Yeong; Liong, Men Long; Riley, Donald E.

    2008-01-01

    Background Prostatitis describes a combination of infectious diseases (acute and chronic bacterial prostatitis), chronic pelvic pain syndrome, and asymptomatic inflammation. Materials and methods We employed evidence-based methods to review the epidemiology of prostatitis syndromes. Results The prevalence of prostatitis symptoms could be compared in five studies surveying 10 617 men. Overall, 873 participants met various criteria for prostatitis, representing an overall rate of 8.2%, with prevalence ranging from 2.2 to 9.7%. A history of sexually transmitted diseases was associated with an increased risk for prostatitis symptoms. Men reporting a history of prostatitis symptoms had a substantially increased rate of benign prostatic hyperplasia, lower urinary tract symptoms and prostate cancer. In one study, the incidence of physician-diagnosed prostatitis was 4.9 cases per 1000 person-years. Two studies suggest that about one-third of men reporting prostatitis symptoms had resolution after 1 year. Patients with previous episodes and more severe symptoms are at higher risk for chronic pelvic pain. Discussion The prevalence of prostatitis symptoms is high, comparable to rates of ischamic heart disease and diabetes. Clinical evaluation appears necessary to verify that prostatitis is responsible for patients’ symptoms. Prostatitis symptoms may increase a man’s risk for benign prostate hypertrophy, lower urinary tract symptoms and prostate cancer. We need to define natural history and consequences of prostatitis, develop better algorithms for diagnosis and treatment, and develop strategies for prevention. PMID:18164907

  20. Epidemiology of Lung Cancer

    Science.gov (United States)

    Brock, Malcolm V.; Ford, Jean G.; Samet, Jonathan M.; Spivack, Simon D.

    2013-01-01

    Background: Ever since a lung cancer epidemic emerged in the mid-1900s, the epidemiology of lung cancer has been intensively investigated to characterize its causes and patterns of occurrence. This report summarizes the key findings of this research. Methods: A detailed literature search provided the basis for a narrative review, identifying and summarizing key reports on population patterns and factors that affect lung cancer risk. Results: Established environmental risk factors for lung cancer include smoking cigarettes and other tobacco products and exposure to secondhand tobacco smoke, occupational lung carcinogens, radiation, and indoor and outdoor air pollution. Cigarette smoking is the predominant cause of lung cancer and the leading worldwide cause of cancer death. Smoking prevalence in developing nations has increased, starting new lung cancer epidemics in these nations. A positive family history and acquired lung disease are examples of host factors that are clinically useful risk indicators. Risk prediction models based on lung cancer risk factors have been developed, but further refinement is needed to provide clinically useful risk stratification. Promising biomarkers of lung cancer risk and early detection have been identified, but none are ready for broad clinical application. Conclusions: Almost all lung cancer deaths are caused by cigarette smoking, underscoring the need for ongoing efforts at tobacco control throughout the world. Further research is needed into the reasons underlying lung cancer disparities, the causes of lung cancer in never smokers, the potential role of HIV in lung carcinogenesis, and the development of biomarkers. PMID:23649439

  1. TUBERCULOSIS: EPIDEMIOLOGY AND CONTROL

    Directory of Open Access Journals (Sweden)

    Giorgia Sulis

    2014-10-01

    Full Text Available Tuberculosis (TB is a major public health concern worldwide: despite a regular, although slow, decline in incidence over the last decade, as many as 8.6 million new cases and 1.3 million deaths were estimated to have occurred in 2012. TB is by all means a poverty-related disease, mainly affecting the most vulnerable populations in the poorest countries. The presence of multidrug-resistant strains of M. tuberculosis in most countries, with some where prevalence is high, is among the major challenges for TB control, which may hinder recent achievements especially in some settings. Early TB case detection especially in resource-constrained settings and in marginalized groups remains a challenge, and about 3 million people are estimated to remain undiagnosed or not notified and untreated. The World Health Organization (WHO has recently launched the new global TB strategy for the “post-2015 era” aimed at “ending the global TB epidemic” by 2035, based on the three pillars that emphasize patient-centred TB care and prevention, bold policies and supportive systems, and intensified research and innovation. This paper aims to provide an overview of the global TB epidemiology as well as of the main challenges that must be faced to eliminate the disease as a public health problem everywhere.

  2. Epidemiology of severe trauma.

    Science.gov (United States)

    Alberdi, F; García, I; Atutxa, L; Zabarte, M

    2014-12-01

    Major injury is the sixth leading cause of death worldwide. Among those under 35 years of age, it is the leading cause of death and disability. Traffic accidents alone are the main cause, fundamentally in low- and middle-income countries. Patients over 65 years of age are an increasingly affected group. For similar levels of injury, these patients have twice the mortality rate of young individuals, due to the existence of important comorbidities and associated treatments, and are more likely to die of medical complications late during hospital admission. No worldwide, standardized definitions exist for documenting, reporting and comparing data on severely injured trauma patients. The most common trauma scores are the Abbreviated Injury Scale (AIS), the Injury Severity Score (ISS) and the Trauma and Injury severity Score (TRISS). Documenting the burden of injury also requires evaluation of the impact of post-trauma impairments, disabilities and handicaps. Trauma epidemiology helps define health service and research priorities, contributes to identify disadvantaged groups, and also facilitates the elaboration of comparable measures for outcome predictions. Copyright © 2014 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.

  3. Radiobiology and Epidemiology

    International Nuclear Information System (INIS)

    Desaintes, C; Holmstock, L.

    2001-01-01

    The main objectives of research in the field of radiobiology and epidemiology performed at the Belgian Nuclear Research Centre SCK-CEN are: (1) to study cancer mortality in nuclear workers in Belgium and to co-ordinate the Belgian contribution to the 'International Collaborative Study of Cancer Risk among Radiation Workers in the Nuclear Industry'; (2) to elucidate the molecular basis of individual susceptibility to ionizing radiation in mammalian embryo during the early phases of its development; (3) to assess the genetic risk of maternal exposure to ionizing radiation; (4) to elucidate the cellular mechanisms leading to brain damage after prenatal irradiation; (5) to monitor the early variations of gene expression induced by ionising radiation and cytokines; (6) to evaluate the use of cytokines and natural substances for improving radiotherapy protocols; (6) to advise authorities and to provide the general population with adequate information concerning the health risk arising from radiation exposure. Progress and major achievements in these topical areas in 2000 are reported

  4. Radiobiology and Epidemiology

    Energy Technology Data Exchange (ETDEWEB)

    Desaintes, C; Holmstock, L

    2001-04-01

    The main objectives of research in the field of radiobiology and epidemiology performed at the Belgian Nuclear Research Centre SCK-CEN are: (1) to study cancer mortality in nuclear workers in Belgium and to co-ordinate the Belgian contribution to the 'International Collaborative Study of Cancer Risk among Radiation Workers in the Nuclear Industry'; (2) to elucidate the molecular basis of individual susceptibility to ionizing radiation in mammalian embryo during the early phases of its development; (3) to assess the genetic risk of maternal exposure to ionizing radiation; (4) to elucidate the cellular mechanisms leading to brain damage after prenatal irradiation; (5) to monitor the early variations of gene expression induced by ionising radiation and cytokines; (6) to evaluate the use of cytokines and natural substances for improving radiotherapy protocols; (6) to advise authorities and to provide the general population with adequate information concerning the health risk arising from radiation exposure. Progress and major achievements in these topical areas in 2000 are reported.

  5. Indoor radon epidemiological study

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, E; Tomasek, L; Mueller, T [National Radiation Protection Institute, Prague (Czech Republic); Placek, V [Inst. for Expertises and Emergencies, Pribram-Kamenna (Czech Republic); Matzner, J; Heribanova, A [State Office for Nuclear Safety, Prague (Czech Republic)

    1996-12-31

    The study is a long-term prospective cohort study of lung cancer and possibility other causes of death. The study population includes inhabitants of the area, who had resided there for at three years and at least one of these between 1.1.1960 and 21.12.1989. A total of 11865 inhabitants satisfied these criteria. The cumulative exposure of each respondent is being assessed on the basis of measurements in dwellings, time spent there and estimation of previous exposure levels by a model accounting for constructional changes in buildings. One year lasting measurements of radon daughter products by integral dosimeters (Kodak film LR 115) were performed in practically all dwellings of the specified area. Radon measurements in houses in term of equilibrium concentration are compared with the results of a pilot study in Petrovice in 1990-91 which gave the stimulus for the epidemiological study. The distribution of death causes and ratio of observed (O) to expected (E) cases among collected death cases in the cohort, generally, somewhat lower ratios than one reflect the non-industrial character of the region, with the exception of lung cancer in man. The differences in the O/E ratios for lung cancer among the separate communities indicate that even in the situation of generally lower mortality, the dependence of lung cancer mortality on radon.

  6. Mozambique field epidemiology and laboratory training program: a pathway for strengthening human resources in applied epidemiology.

    Science.gov (United States)

    Baltazar, Cynthia Semá; Taibo, Cátia; Sacarlal, Jahit; Gujral, Lorna; Salomão, Cristolde; Doyle, Timothy

    2017-01-01

    In the last decades, Mozambique has been undergoing demographic, epidemiological, economic and social transitions, which have all had a notable impact on the National Health System. New challenges have emerged, causing a need to expand the preparation and response to emerging disease threats and public health emergencies. We describe the structure and function of the Mozambique Field Epidemiology Training Program (MZ-FELTP) and the main outputs achieved during the first 6 years of program implementation (consisting of 3 cohorts). We also outline the contribution of the program to the National Health System and assess the retention of the graduates. The MZ-FELTP is a post-graduate in-service training program, based on the acquisition of skills, within two tracks: applied epidemiology and laboratory management. The program was established in 2010, with the objective of strengthening capacity in applied epidemiology and laboratory management, so that events of public health importance can be detected and investigated in a timely and effective manner. The program is in its seventh year, having successfully trained 36 health professionals in the advanced course. During the first six years of the program, more than 40 outbreaks were investigated, 37 surveillance system evaluations were conducted and 39 descriptive data analyses were performed. Surveillance activities were implemented for mass events and emergency situations. In addition, more than 100 oral and poster presentations were given by trainees at national and international conferences. The MZ-FELTP has helped provide the Ministry of Health with the human and technical resources and operational capacity, to rapidly and effectively respond to major public health challenges in the country. The continuous involvement of key stakeholders is necessary for the continuation, expansion and ongoing sustainability of the program.

  7. Women, transition and strikes in Serbia

    OpenAIRE

    Novaković, Nada G.

    2014-01-01

    The author, in a sociological way, describes and analyzes the concepts of transition, privatization and strikes in Serbia, particularly the place of women in it. It examines the most important economic and social causes and consequences of these phenomena. The main hypothesis is: women's strikes in the Serbian transition are less efficient than strikes and public protests of women in the developed world and the second Yugoslavia. A strike is a class conflict, in which the workers are fighting...

  8. The zinc dyshomeostasis hypothesis of Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Travis J A Craddock

    Full Text Available Alzheimer's disease (AD is the most common form of dementia in the elderly. Hallmark AD neuropathology includes extracellular amyloid plaques composed largely of the amyloid-β protein (Aβ, intracellular neurofibrillary tangles (NFTs composed of hyper-phosphorylated microtubule-associated protein tau (MAP-tau, and microtubule destabilization. Early-onset autosomal dominant AD genes are associated with excessive Aβ accumulation, however cognitive impairment best correlates with NFTs and disrupted microtubules. The mechanisms linking Aβ and NFT pathologies in AD are unknown. Here, we propose that sequestration of zinc by Aβ-amyloid deposits (Aβ oligomers and plaques not only drives Aβ aggregation, but also disrupts zinc homeostasis in zinc-enriched brain regions important for memory and vulnerable to AD pathology, resulting in intra-neuronal zinc levels, which are either too low, or excessively high. To evaluate this hypothesis, we 1 used molecular modeling of zinc binding to the microtubule component protein tubulin, identifying specific, high-affinity zinc binding sites that influence side-to-side tubulin interaction, the sensitive link in microtubule polymerization and stability. We also 2 performed kinetic modeling showing zinc distribution in extra-neuronal Aβ deposits can reduce intra-neuronal zinc binding to microtubules, destabilizing microtubules. Finally, we 3 used metallomic imaging mass spectrometry (MIMS to show anatomically-localized and age-dependent zinc dyshomeostasis in specific brain regions of Tg2576 transgenic, mice, a model for AD. We found excess zinc in brain regions associated with memory processing and NFT pathology. Overall, we present a theoretical framework and support for a new theory of AD linking extra-neuronal Aβ amyloid to intra-neuronal NFTs and cognitive dysfunction. The connection, we propose, is based on β-amyloid-induced alterations in zinc ion concentration inside neurons affecting stability of

  9. The zinc dyshomeostasis hypothesis of Alzheimer's disease.

    Science.gov (United States)

    Craddock, Travis J A; Tuszynski, Jack A; Chopra, Deepak; Casey, Noel; Goldstein, Lee E; Hameroff, Stuart R; Tanzi, Rudolph E

    2012-01-01

    Alzheimer's disease (AD) is the most common form of dementia in the elderly. Hallmark AD neuropathology includes extracellular amyloid plaques composed largely of the amyloid-β protein (Aβ), intracellular neurofibrillary tangles (NFTs) composed of hyper-phosphorylated microtubule-associated protein tau (MAP-tau), and microtubule destabilization. Early-onset autosomal dominant AD genes are associated with excessive Aβ accumulation, however cognitive impairment best correlates with NFTs and disrupted microtubules. The mechanisms linking Aβ and NFT pathologies in AD are unknown. Here, we propose that sequestration of zinc by Aβ-amyloid deposits (Aβ oligomers and plaques) not only drives Aβ aggregation, but also disrupts zinc homeostasis in zinc-enriched brain regions important for memory and vulnerable to AD pathology, resulting in intra-neuronal zinc levels, which are either too low, or excessively high. To evaluate this hypothesis, we 1) used molecular modeling of zinc binding to the microtubule component protein tubulin, identifying specific, high-affinity zinc binding sites that influence side-to-side tubulin interaction, the sensitive link in microtubule polymerization and stability. We also 2) performed kinetic modeling showing zinc distribution in extra-neuronal Aβ deposits can reduce intra-neuronal zinc binding to microtubules, destabilizing microtubules. Finally, we 3) used metallomic imaging mass spectrometry (MIMS) to show anatomically-localized and age-dependent zinc dyshomeostasis in specific brain regions of Tg2576 transgenic, mice, a model for AD. We found excess zinc in brain regions associated with memory processing and NFT pathology. Overall, we present a theoretical framework and support for a new theory of AD linking extra-neuronal Aβ amyloid to intra-neuronal NFTs and cognitive dysfunction. The connection, we propose, is based on β-amyloid-induced alterations in zinc ion concentration inside neurons affecting stability of polymerized

  10. Metabolomics and Epidemiology Working Group

    Science.gov (United States)

    The Metabolomics and Epidemiology (MetEpi) Working Group promotes metabolomics analyses in population-based studies, as well as advancement in the field of metabolomics for broader biomedical and public health research.

  11. Genomic Resources for Cancer Epidemiology

    Science.gov (United States)

    This page provides links to research resources, complied by the Epidemiology and Genomics Research Program, that may be of interest to genetic epidemiologists conducting cancer research, but is not exhaustive.

  12. Occupational reproductive epidemiology: Pt. 1

    International Nuclear Information System (INIS)

    Roman, Eve; Doyle, Pat

    1993-01-01

    The authors review the current state of knowledge about possible adverse effects of hazardous paternal workplace exposures on human reproduction is scant. The methodology for studying possible association between occupational exposures and adverse reproductive events is not well developed. More detailed laboratory and epidemiological research is clearly required, and better collaboration between these two disciplines is needed. Associations suggested in the course of epidemiological research need to be tested in the laboratory, and vice versa. (author)

  13. Transitions from Military Rule in South America: The Obligational Legitimacy Hypothesis.

    Science.gov (United States)

    1987-12-01

    34will have to make use, [once in power] of some degree or some form of electoral legitimation."󈨅 Finer states, "They seek, in short, to exercise a...political jeito and casuismos (gerrymandering, electoral engineering, etc.) to establish a pro military party, the National Renovating Alliance (ARENA...and Co., 1906. Molineu, Harold. U.S. Policy Toward Latin America. Boulder: Westview Press, 1986. Moro, Comodoro D. Ruben. Historico Del Conflicto Del

  14. Transitioning to a Data Driven Mental Health Practice: Collaborative Expert Sessions for Knowledge and Hypothesis Finding

    Directory of Open Access Journals (Sweden)

    Vincent Menger

    2016-01-01

    Full Text Available The surge in the amount of available data in health care enables a novel, exploratory research approach that revolves around finding new knowledge and unexpected hypotheses from data instead of carrying out well-defined data analysis tasks. We propose a specification of the Cross Industry Standard Process for Data Mining (CRISP-DM, suitable for conducting expert sessions that focus on finding new knowledge and hypotheses in collaboration with local workforce. Our proposed specification that we name CRISP-IDM is evaluated in a case study at the psychiatry department of the University Medical Center Utrecht. Expert interviews were conducted to identify seven research themes in the psychiatry department, which were researched in cooperation with local health care professionals using data visualization as a modeling tool. During 19 expert sessions, two results that were directly implemented and 29 hypotheses for further research were found, of which 24 were not imagined during the initial expert interviews. Our work demonstrates the viability and benefits of involving work floor people in the analyses and the possibility to effectively find new knowledge and hypotheses using our CRISP-IDM method.

  15. Transitioning to a Data Driven Mental Health Practice: Collaborative Expert Sessions for Knowledge and Hypothesis Finding.

    Science.gov (United States)

    Menger, Vincent; Spruit, Marco; Hagoort, Karin; Scheepers, Floor

    2016-01-01

    The surge in the amount of available data in health care enables a novel, exploratory research approach that revolves around finding new knowledge and unexpected hypotheses from data instead of carrying out well-defined data analysis tasks. We propose a specification of the Cross Industry Standard Process for Data Mining (CRISP-DM), suitable for conducting expert sessions that focus on finding new knowledge and hypotheses in collaboration with local workforce. Our proposed specification that we name CRISP-IDM is evaluated in a case study at the psychiatry department of the University Medical Center Utrecht. Expert interviews were conducted to identify seven research themes in the psychiatry department, which were researched in cooperation with local health care professionals using data visualization as a modeling tool. During 19 expert sessions, two results that were directly implemented and 29 hypotheses for further research were found, of which 24 were not imagined during the initial expert interviews. Our work demonstrates the viability and benefits of involving work floor people in the analyses and the possibility to effectively find new knowledge and hypotheses using our CRISP-IDM method.

  16. Transitioning to a Data Driven Mental Health Practice : Collaborative Expert Sessions for Knowledge and Hypothesis Finding

    NARCIS (Netherlands)

    Menger, Vincent; Spruit, Marco; Hagoort, Karin; Scheepers, Floor

    2016-01-01

    The surge in the amount of available data in health care enables a novel, exploratory research approach that revolves around finding new knowledge and unexpected hypotheses from data instead of carrying out well-defined data analysis tasks. We propose a specification of the Cross Industry Standard

  17. Using Two Different Approaches to Assess Dietary Patterns: Hypothesis-Driven and Data-Driven Analysis

    Directory of Open Access Journals (Sweden)

    Ágatha Nogueira Previdelli

    2016-09-01

    Full Text Available The use of dietary patterns to assess dietary intake has become increasingly common in nutritional epidemiology studies due to the complexity and multidimensionality of the diet. Currently, two main approaches have been widely used to assess dietary patterns: data-driven and hypothesis-driven analysis. Since the methods explore different angles of dietary intake, using both approaches simultaneously might yield complementary and useful information; thus, we aimed to use both approaches to gain knowledge of adolescents’ dietary patterns. Food intake from a cross-sectional survey with 295 adolescents was assessed by 24 h dietary recall (24HR. In hypothesis-driven analysis, based on the American National Cancer Institute method, the usual intake of Brazilian Healthy Eating Index Revised components were estimated. In the data-driven approach, the usual intake of foods/food groups was estimated by the Multiple Source Method. In the results, hypothesis-driven analysis showed low scores for Whole grains, Total vegetables, Total fruit and Whole fruits, while, in data-driven analysis, fruits and whole grains were not presented in any pattern. High intakes of sodium, fats and sugars were observed in hypothesis-driven analysis with low total scores for Sodium, Saturated fat and SoFAA (calories from solid fat, alcohol and added sugar components in agreement, while the data-driven approach showed the intake of several foods/food groups rich in these nutrients, such as butter/margarine, cookies, chocolate powder, whole milk, cheese, processed meat/cold cuts and candies. In this study, using both approaches at the same time provided consistent and complementary information with regard to assessing the overall dietary habits that will be important in order to drive public health programs, and improve their efficiency to monitor and evaluate the dietary patterns of populations.

  18. Early life exposure to antibiotics and the risk of childhood allergic diseases: an update from the perspective of the hygiene hypothesis.

    Science.gov (United States)

    Kuo, Chang-Hung; Kuo, Hsuan-Fu; Huang, Ching-Hua; Yang, San-Nan; Lee, Min-Sheng; Hung, Chih-Hsing

    2013-10-01

    The prevalence of allergic diseases has been growing rapidly in industrial countries during recent decades. It is postulated that growing up with less microbial exposure may render the immune system susceptible to a T helper type 2 (Th2)-predominant allergic response-also known as the hygiene hypothesis. This review delineates recent epidemiological and experimental evidence for the hygiene hypothesis, and integrates this hypothesis into the association between early life exposure to antibiotics and the development of allergic diseases and asthma. Several retrospective or prospective epidemiological studies reveal that early exposure to antibiotics may be positively associated with the development of allergic diseases and asthma. However, the conclusion is inconsistent. Experimental studies show that antibiotics may induce the Th2-skewed response by suppressing the T helper type 1 (Th1) response through inhibition of Th1 cytokines and disruption of the natural course of infection, or by disturbing the microflora of the gastrointestinal (GI) tract and therefore jeopardizing the establishment of oral tolerance and regulatory T cell immune responses. The hygiene hypothesis may not be the only explanation for the rapid increase in the prevalence of allergic diseases and asthma. Further epidemiological and experimental studies addressing the issue of the impact of environmental factors on the development of allergic diseases and the underlying mechanisms may unveil novel strategies for the prevention and treatment of allergic diseases in the future. Copyright © 2013. Published by Elsevier B.V.

  19. Invited Commentary: Can Issues With Reproducibility in Science Be Blamed on Hypothesis Testing?

    Science.gov (United States)

    Weinberg, Clarice R

    2017-09-15

    In the accompanying article (Am J Epidemiol. 2017;186(6):646-647), Dr. Timothy Lash makes a forceful case that the problems with reproducibility in science stem from our "culture" of null hypothesis significance testing. He notes that when attention is selectively given to statistically significant findings, the estimated effects will be systematically biased away from the null. Here I revisit the recent history of genetic epidemiology and argue for retaining statistical testing as an important part of the tool kit. Particularly when many factors are considered in an agnostic way, in what Lash calls "innovative" research, investigators need a selection strategy to identify which findings are most likely to be genuine, and hence worthy of further study. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  20. Invited Commentary: Can Issues With Reproducibility in Science Be Blamed on Hypothesis Testing?

    Science.gov (United States)

    Weinberg, Clarice R.

    2017-01-01

    Abstract In the accompanying article (Am J Epidemiol. 2017;186(6):646–647), Dr. Timothy Lash makes a forceful case that the problems with reproducibility in science stem from our “culture” of null hypothesis significance testing. He notes that when attention is selectively given to statistically significant findings, the estimated effects will be systematically biased away from the null. Here I revisit the recent history of genetic epidemiology and argue for retaining statistical testing as an important part of the tool kit. Particularly when many factors are considered in an agnostic way, in what Lash calls “innovative” research, investigators need a selection strategy to identify which findings are most likely to be genuine, and hence worthy of further study. PMID:28938713

  1. Men’s Perception of Raped Women: Test of the Sexually Transmitted Disease Hypothesis and the Cuckoldry Hypothesis

    Directory of Open Access Journals (Sweden)

    Prokop Pavol

    2016-06-01

    Full Text Available Rape is a recurrent adaptive problem of female humans and females of a number of non-human animals. Rape has various physiological and reproductive costs to the victim. The costs of rape are furthermore exaggerated by social rejection and blaming of a victim, particularly by men. The negative perception of raped women by men has received little attention from an evolutionary perspective. Across two independent studies, we investigated whether the risk of sexually transmitted diseases (the STD hypothesis, Hypothesis 1 or paternity uncertainty (the cuckoldry hypothesis, Hypothesis 2 influence the negative perception of raped women by men. Raped women received lower attractiveness score than non-raped women, especially in long-term mate attractiveness score. The perceived attractiveness of raped women was not influenced by the presence of experimentally manipulated STD cues on faces of putative rapists. Women raped by three men received lower attractiveness score than women raped by one man. These results provide stronger support for the cuckoldry hypothesis (Hypothesis 2 than for the STD hypothesis (Hypothesis 1. Single men perceived raped women as more attractive than men in a committed relationship (Hypothesis 3, suggesting that the mating opportunities mediate men’s perception of victims of rape. Overall, our results suggest that the risk of cuckoldry underlie the negative perception of victims of rape by men rather than the fear of disease transmission.

  2. Epidemiology of idiopathic pulmonary fibrosis

    Directory of Open Access Journals (Sweden)

    Ley B

    2013-11-01

    Full Text Available Brett Ley, Harold R Collard Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, California, USA Abstract: Idiopathic pulmonary fibrosis is a chronic fibrotic lung disease of unknown cause that occurs in adults and has a poor prognosis. Its epidemiology has been difficult to study because of its rarity and evolution in diagnostic and coding practices. Though uncommon, it is likely underappreciated both in terms of its occurrence (ie, incidence, prevalence and public health impact (ie, health care costs and resource utilization. Incidence and mortality appear to be on the rise, and prevalence is expected to increase with the aging population. Potential risk factors include occupational and environmental exposures, tobacco smoking, gastroesophageal reflux, and genetic factors. An accurate understanding of its epidemiology is important, especially as novel therapies are emerging. Keywords: idiopathic pulmonary fibrosis, epidemiology, incidence, prevalence, mortality, risk factors

  3. Epidemiología de campo y epidemiología social Field epidemiology and social epidemiology

    Directory of Open Access Journals (Sweden)

    Javier Segura del Pozo

    2006-03-01

    Full Text Available Mediante la comparación de la epidemiología de campo y la epidemiología social, se pretende reflexionar sobre los imaginarios no explícitos que operan en ambos ámbitos, necesariamente convergentes, sobre los obstáculos de la práctica epidemiológica actual para alcanzar su función social y sobre la necesidad de cambiar las bases epistemológicas, metodológicas y prácticas que operan en la epidemiología, empezando por la formación del epidemiólogo de campo. La epidemiología de campo tiende a la acción sin marco teórico. La epidemiología social, por el contrario, tiende a los desarrollos teóricos (reflexión e investigación sobre los determinantes sociales alejados de la acción, debido a los limitantes para cambiar las políticas públicas. Otras diferencias se sitúan en el nivel de intervención (micro/macroespacios, el objeto de intervención (control del brote frente a control de las desigualdades y en la forma de articular la comunicación con la sociedad. Se asemejan en la preocupación por el método, la predominancia de una orientación positivista y condicionada por la estadística, aunque en proceso de cierta apertura epistemológica, la tensión experimentada entre relacionarse con un mundo virtual de bases de datos o con la sociedad real, su situación en la periferia del sistema político-social-institucional-profesional y por estar abocadas a la frustración profesional. Finalmente, se formulan 10 interrogantes a los epidemiólogos de campo sobre su práctica actual, a través de los cuales se podría evaluar si están realizando una epidemiología social, y se sugieren cambios para introducir en la formación y práctica del epidemiólogo.Comparing field epidemiology and social epidemiology, we pretend to think about the no explicit images and meanings operating in both necessary convergent fields, about the obstacles present in epidemiological practice to fulfil its social function and about the necessity of

  4. New Hypothesis for SOFC Ceramic Oxygen Electrode Mechanisms

    DEFF Research Database (Denmark)

    Mogensen, Mogens Bjerg; Chatzichristodoulou, Christodoulos; Graves, Christopher R.

    2016-01-01

    A new hypothesis for the electrochemical reaction mechanism in solid oxide cell ceramic oxygen electrodes is proposed based on literature including our own results. The hypothesis postulates that the observed thin layers of SrO-La2O3 on top of ceramic perovskite and other Ruddlesden-Popper...

  5. Assess the Critical Period Hypothesis in Second Language Acquisition

    Science.gov (United States)

    Du, Lihong

    2010-01-01

    The Critical Period Hypothesis aims to investigate the reason for significant difference between first language acquisition and second language acquisition. Over the past few decades, researchers carried out a series of studies to test the validity of the hypothesis. Although there were certain limitations in these studies, most of their results…

  6. Dynamical agents' strategies and the fractal market hypothesis

    Czech Academy of Sciences Publication Activity Database

    Vácha, Lukáš; Vošvrda, Miloslav

    2005-01-01

    Roč. 14, č. 2 (2005), s. 172-179 ISSN 1210-0455 Grant - others:GA UK(CZ) 454/2004/A EK/FSV Institutional research plan: CEZ:AV0Z10750506 Keywords : efficient market hypothesis * fractal market hypothesis * agent's investment horizons Subject RIV: AH - Economics

  7. An Exercise for Illustrating the Logic of Hypothesis Testing

    Science.gov (United States)

    Lawton, Leigh

    2009-01-01

    Hypothesis testing is one of the more difficult concepts for students to master in a basic, undergraduate statistics course. Students often are puzzled as to why statisticians simply don't calculate the probability that a hypothesis is true. This article presents an exercise that forces students to lay out on their own a procedure for testing a…

  8. A default Bayesian hypothesis test for ANOVA designs

    NARCIS (Netherlands)

    Wetzels, R.; Grasman, R.P.P.P.; Wagenmakers, E.J.

    2012-01-01

    This article presents a Bayesian hypothesis test for analysis of variance (ANOVA) designs. The test is an application of standard Bayesian methods for variable selection in regression models. We illustrate the effect of various g-priors on the ANOVA hypothesis test. The Bayesian test for ANOVA

  9. Adaptation hypothesis of biological efficiency of ionizing radiation

    International Nuclear Information System (INIS)

    Kudritskij, Yu.K.; Georgievskij, A.B.; Karpov, V.I.

    1992-01-01

    Adaptation hypothesis of biological efficiency of ionizing radiation is based on acknowledgement of invariance of fundamental laws and principles of biology related to unity of biota and media, evolution and adaptation for radiobiology. The basic arguments for adaptation hypothesis validity, its correspondence to the requirements imposed on scientific hypothes are presented

  10. New methods of testing nonlinear hypothesis using iterative NLLS estimator

    Science.gov (United States)

    Mahaboob, B.; Venkateswarlu, B.; Mokeshrayalu, G.; Balasiddamuni, P.

    2017-11-01

    This research paper discusses the method of testing nonlinear hypothesis using iterative Nonlinear Least Squares (NLLS) estimator. Takeshi Amemiya [1] explained this method. However in the present research paper, a modified Wald test statistic due to Engle, Robert [6] is proposed to test the nonlinear hypothesis using iterative NLLS estimator. An alternative method for testing nonlinear hypothesis using iterative NLLS estimator based on nonlinear hypothesis using iterative NLLS estimator based on nonlinear studentized residuals has been proposed. In this research article an innovative method of testing nonlinear hypothesis using iterative restricted NLLS estimator is derived. Pesaran and Deaton [10] explained the methods of testing nonlinear hypothesis. This paper uses asymptotic properties of nonlinear least squares estimator proposed by Jenrich [8]. The main purpose of this paper is to provide very innovative methods of testing nonlinear hypothesis using iterative NLLS estimator, iterative NLLS estimator based on nonlinear studentized residuals and iterative restricted NLLS estimator. Eakambaram et al. [12] discussed least absolute deviation estimations versus nonlinear regression model with heteroscedastic errors and also they studied the problem of heteroscedasticity with reference to nonlinear regression models with suitable illustration. William Grene [13] examined the interaction effect in nonlinear models disused by Ai and Norton [14] and suggested ways to examine the effects that do not involve statistical testing. Peter [15] provided guidelines for identifying composite hypothesis and addressing the probability of false rejection for multiple hypotheses.

  11. The Younger Dryas impact hypothesis: A critical review

    NARCIS (Netherlands)

    van Hoesel, A.; Hoek, W.Z.; Pennock, G.M.; Drury, Martyn

    2014-01-01

    The Younger Dryas impact hypothesis suggests that multiple extraterrestrial airbursts or impacts resulted in the Younger Dryas cooling, extensive wildfires, megafaunal extinctions and changes in human population. After the hypothesis was first published in 2007, it gained much criticism, as the

  12. Molecular epidemiology of human rhinoviruses

    OpenAIRE

    Savolainen-Kopra, Carita

    2006-01-01

    The first part of this work investigates the molecular epidemiology of a human enterovirus (HEV), echovirus 30 (E-30). This project is part of a series of studies performed in our research team analyzing the molecular epidemiology of HEV-B viruses. A total of 129 virus strains had been isolated in different parts of Europe. The sequence analysis was performed in three different genomic regions: 420 nucleotides (nt) in the VP4/VP2 capsid protein coding region, the entire VP1 capsid protein cod...

  13. Topological transitions in the theory of spacetime

    International Nuclear Information System (INIS)

    Konstantinov, M.Y.; Melnikov, V.N.

    1986-01-01

    Results of a realisation of the topological transitions hypothesis are presented. The basic difficulties in the construction of quantum topological transition theory are connected with a necessity to introduce a new non-local interaction defined on a space of topological states. So the general method of construction and study of topological transitions classical models is formulated as a necessary step towards a corresponding quantum description. Their local properties, including an asymptotic behaviour in the neighbourhood of the transition, are studied and applications to problems of gravitation and cosmology are given. The method used is shown to lead to a scalar-tensor theory of topological transitions. Different variants of this theory and its main features are discussed. (author)

  14. Establishing the link between Ostreopsis cf.ovata blooms and human health impacts using ecology and epidemiology

    Directory of Open Access Journals (Sweden)

    Magda Vila

    2016-09-01

    Full Text Available Blooms of the benthic dinoflagellate Ostreopsis have been related to sporadic acute respiratory symptoms and general malaise in people exposed to marine aerosols on some Mediterranean beaches. However, the direct link between recurrent Ostreopsis blooms and health problems has not been clearly established. In order to establish and elucidate the connection, we conducted a joint ecology and epidemiology study in an Ostreopsis hot spot. Throughout the bloom, which extended from the end of June until the end of October 2013, 81% of the human cohort that we studied experienced at least one Ostreopsis-related symptom. Paradoxically, the time when the effects were greatest was during a short time window in early August. This corresponded to the transition from the exponential growth to the stationary phase of the bloom. Negligible symptoms were reported from August to mid-October, during the stationary period of the proliferation, when O. cf. ovata maintained high concentrations of epiphytic cells. No clear patterns in the landward wind component were noted during the time when health effects were greatest. Our main hypothesis is that the irritants present in the aerosol are produced during a particular physiological phase of the Ostreopsis cells during the bloom.

  15. Transit space

    DEFF Research Database (Denmark)

    Raahauge, Kirsten Marie

    2008-01-01

    This article deals with representations of one specific city, Århus, Denmark, especially its central district. The analysis is based on anthropological fieldwork conducted in Skåde Bakker and Fedet, two well-off neighborhoods. The overall purpose of the project is to study perceptions of space...... and the interaction of cultural, social, and spatial organizations, as seen from the point of view of people living in Skåde Bakker and Fedet. The focus is on the city dwellers’ representations of the central district of Århus with specific reference to the concept of transit space. When applied to various Århusian...

  16. Transition region

    International Nuclear Information System (INIS)

    Jordan, C.

    1977-01-01

    The Glossary is designed to be a technical dictionary that will provide solar workers of various specialties, students, other astronomers and theoreticians with concise information on the nature and the properties of phenomena of solar and solar-terrestrial physics. Each term, or group of related terms, is given a concise phenomenological and quantitative description, including the relationship to other phenomena and an interpretation in terms of physical processes. The references are intended to lead the non-specialist reader into the literature. This section deals with: transition region; di-electronic recombination; intersystem or intercombination lines; satellite lines; grazing-incidence optics; and crystal spectrometers. (B.R.H.)

  17. The role of influenza in the epidemiology of pneumonia

    Science.gov (United States)

    Shrestha, Sourya; Foxman, Betsy; Berus, Joshua; van Panhuis, Willem G.; Steiner, Claudia; Viboud, Cécile; Rohani, Pejman

    2015-01-01

    Interactions arising from sequential viral and bacterial infections play important roles in the epidemiological outcome of many respiratory pathogens. Influenza virus has been implicated in the pathogenesis of several respiratory bacterial pathogens commonly associated with pneumonia. Though clinical evidence supporting this interaction is unambiguous, its population-level effects—magnitude, epidemiological impact and variation during pandemic and seasonal outbreaks—remain unclear. To address these unknowns, we used longitudinal influenza and pneumonia incidence data, at different spatial resolutions and across different epidemiological periods, to infer the nature, timing and the intensity of influenza-pneumonia interaction. We used a mechanistic transmission model within a likelihood-based inference framework to carry out formal hypothesis testing. Irrespective of the source of data examined, we found that influenza infection increases the risk of pneumonia by ~100-fold. We found no support for enhanced transmission or severity impact of the interaction. For model-validation, we challenged our fitted model to make out-of-sample pneumonia predictions during pandemic and non-pandemic periods. The consistency in our inference tests carried out on several distinct datasets, and the predictive skill of our model increase confidence in our overall conclusion that influenza infection substantially enhances the risk of pneumonia, though only for a short period. PMID:26486591

  18. Transition state structures in solution

    International Nuclear Information System (INIS)

    Bertran, J.; Lluch, J. M.; Gonzalez-Lafont, A.; Dillet, V.; Perez, V.

    1995-01-01

    In the present paper the location of transition state structures for reactions in solution has been studied. Continuum model calculations have been carried out on the Friedel-Crafts alkylation reaction and a proton transfer through a water molecule between two oxygen atoms in formic acid. In this model the separation between the chemical system and the solvent has been introduced. On the other hand, the discrete Monte Carlo methodology has also been used to simulate the solvent effect on dissociative electron transfer processes. In this model, the hypothesis of separability is not assumed. Finally, the validity of both approaches is discussed

  19. Epidemiological methods: a brief review

    International Nuclear Information System (INIS)

    Winkelstein, W. Jr.

    1983-01-01

    Epidemiology, the study of disease distributions in populations and the factors which influence these distributions, is an observational science, i.e., its data base consists of measurements made on free living individuals characterized by presence or absence of disease states and putative risk factors. Epidemiological studies are usually classified as descriptive or analytical. Descriptive studies are primarily used for planning and evaluating health programs or to generate etiological hypotheses. Analytical studies are primarily used for testing etiological hypotheses. Analytical studies are designed either as cohort investigations in which populations with and without a putative risk factor are followed through time to ascertain their differential incidence of disease, or case-control investigations in which the history of exposure to a putative risk factor is compared among persons with a disease and appropriate controls free of disease. Both descriptive and analytical epidemiological studies have been applied to health physics problems. Examples of such problems and the epidemiological methods used to explore them will be presented

  20. Glossary for econometrics and epidemiology.

    Science.gov (United States)

    Gunasekara, F Imlach; Carter, K; Blakely, T

    2008-10-01

    Epidemiologists and econometricians are often interested in similar topics-socioeconomic position and health outcomes-but the different languages that epidemiologists and economists use to interpret and discuss their results can create a barrier to mutual communication. This glossary defines key terms used in econometrics and epidemiology to assist in bridging this gap.

  1. Killing fields; The epidemiological evidence

    Energy Technology Data Exchange (ETDEWEB)

    Best, Simon

    1990-02-01

    The threat posed by low frequency fields emerged initially because a researcher, looking for environmental factors in childhood leukaemia, observed a link between low voltage, high current power lines and disease occurrence. Cellular evidence now supports the findings but epidemiology still leads the argument. (43 references). (author).

  2. Brain Tumor Epidemiology Consortium (BTEC)

    Science.gov (United States)

    The Brain Tumor Epidemiology Consortium is an open scientific forum organized to foster the development of multi-center, international and inter-disciplinary collaborations that will lead to a better understanding of the etiology, outcomes, and prevention of brain tumors.

  3. Candida infections : detection and epidemiology

    NARCIS (Netherlands)

    Borst, A. (Annemarie)

    2002-01-01

    Despite the fact that the yeast Candida is the number 4 cause of bloodstream infections in the United States and ranks number 8 in Europe, adequate detection methods are lacking. Furthermore, relatively little is known about the epidemiology of Candida. Our aim was to improve the detection and

  4. Panel 1 : Epidemiology and Diagnosis

    NARCIS (Netherlands)

    Homøe, Preben; Kværner, Kari; Casey, Janet R; Damoiseaux, Roger A M J; van Dongen, Thijs M A; Gunasekera, Hasantha; Jensen, Ramon G; Kvestad, Ellen; Morris, Peter S; Weinreich, Heather M

    Objective To create a literature review between 2011 and June 1, 2015, on advances in otitis media (OM) epidemiology and diagnosis (including relevant audiology studies). Data Sources Electronic search engines (PubMed, EMBASE, and Cochrane Library) with a predefined search strategy. Review Methods

  5. [Epidemiology of rabies in Algeria].

    Science.gov (United States)

    Benelmouffok, A; Belkaid, M; Benhassine, M

    An epidemiological study on rabies in Algeria has been carried out on data provided by the "Institut national de Santé publique" and the "Institut Pasteur d'Algérie". It showed that no region is unhurt. The animal reservoir is of the domestic type, essentially the dog. In 40% of cases, bites are due to stray dogs.

  6. TFOS DEWS II Epidemiology Report

    NARCIS (Netherlands)

    Stapleton, Fiona; Alves, Monica; Bunya, Vatinee Y.; Jalbert, Isabelle; Lekhanont, Kaevalin; Malet, Florence; Na, Kyung-Sun; Schaumberg, Debra; Uchino, Miki; Vehof, Jelle; Viso, Eloy; Vitale, Susan; Jones, Lyndon

    The subcommittee reviewed the prevalence, incidence, risk factors, natural history, morbidity and questionnaires reported in epidemiological studies of dry eye disease (DED). A meta-analysis of published prevalence data estimated the impact of age and sex. Global mapping of prevalence was

  7. Radiation epidemiology: Past and present

    International Nuclear Information System (INIS)

    Boice, J.D. Jr.

    1997-01-01

    Major advancements in radiation epidemiology have occurred during the last several years in studies of atomic bomb survivors, patients given medical radiation, and radiation workers, including underground miners. Risks associated with the Chernobyl accident, indoor radon and childhood exposure to I-131 have yet to be elucidated. Situations in the former Soviet Union around Chelyabinsk, a nuclear installation in the southern Urals, and in the Altai, which received radioactive fallout from weapons testing at Semipalatinsk, Kazakhstan, have the potential to provide information on the effects of chronic radiation exposure. Since Roentgen's discovery of x-rays just 100 years ago, a tremendous amount of knowledge has been accumulated about human health effects following irradiation. The 1994 UNSCEAR report contains the latest compilation and synthesis of radiation epidemiology. This overview will cover epidemiology from a radiation perspective. The different types of study methodologies will be described, followed by a kaleidoscope coverage of past and present studies; ending with some remaining questions in radiation epidemiology. This should set the stage for future chapters, and stimulate thinking about implications of the new data on radiation cancer risks

  8. [Occupational epidemiology: some methodological considerations].

    Science.gov (United States)

    Alvear-Galindo, María Guadalupe; del Pilar Paz-Román, María

    2006-01-01

    During the last decade, occupational epidemiology has gained a great importance, not only because of the increase of pollutants and their noxiousness, but also because it has gone from the descriptive to the analytic level. The purpose of this work is to present what has been reported on epidemiological studies, different ways of characterizing and measuring occupational exposure, by emphasizing slants of exposure and selection measurement. In the reviewed studies, an interest in improving the exposure evaluation has been shown. The mainly reported measurement slants are the ways of measuring and classifying the exposure. The main designs were transversal with the use of matrixes to improve the evaluation of exposure. Conditions of hygiene and security were considered in order to control the quality of the information. This information was analyzed with different criteria. Some of the elements that hinder the research on occupational epidemiology are a mixed exposure, small populations, lack of exposure data, low levels of exposure and long periods of illness latency. Some breakthroughs in the strategies of epidemiological analysis and some other areas of knowledge have made possible a better understanding of work and health conditions of workers.

  9. Renal damage mediated by oxidative stress: a hypothesis of protective effects of red wine.

    Science.gov (United States)

    Rodrigo, Ramón; Rivera, Gonzalo

    2002-08-01

    Over the last decade, oxidative stress has been implicated in the pathogenesis of a wide variety of seemingly unrelated renal diseases. Epidemiological studies have documented an association of moderate wine consumption with a decreased risk of cardiovascular and neurological diseases; however, similar studies in the kidney are still lacking. The kidney is an organ highly vulnerable to damage caused by reactive oxygen species (ROS), likely due to the abundance of polyunsaturated fatty acids in the composition of renal lipids. ROS are involved in the pathogenic mechanism of conditions such as glomerulosclerosis and tubulointerstitial fibrosis. The health benefits of moderate consumption of red wine can be partly attributed to its antioxidant properties. Indeed, the kidney antioxidant defense system is enhanced after chronic exposure to moderate amounts of wine, a response arising from the combined effects of ethanol and the nonalcoholic components, mainly polyphenols. Polyphenols behave as potent ROS scavengers and metal chelators; ethanol, in turn, modulates the activity of antioxidant enzymes. Therefore, a hypothesis that red wine causes a decreased vulnerability of the kidney to the oxidative challenges could be proposed. This view is partly supported by direct evidences indicating that wine and antioxidants isolated from red wine, as well as other antioxidants, significantly attenuate or prevent the oxidative damage to the kidney. The present hypothesis paper provides a collective body of evidence suggesting a protective role of moderate wine consumption against the production and progression of renal diseases, based on the existing concepts on the pathophysiology of kidney injury mediated by oxidative stress.

  10. Cholesterol as a Causative Factor in Alzheimer Disease: A Debatable Hypothesis

    Science.gov (United States)

    Wood, W. Gibson; Li, Ling; Müller, Walter E.; Eckert, Gunter P.

    2014-01-01

    High serum/plasma cholesterol levels have been suggested as a risk factor for Alzheimer disease (AD). Some reports, mostly retrospective epidemiological studies, have observed a decreased prevalence of AD in patients taking the cholesterol lowering drugs, statins. The strongest evidence causally linking cholesterol to AD is provided by experimental studies showing that adding/reducing cholesterol alters amyloid precursor protein (APP) and amyloid beta-protein (Aβ) levels. However, there are problems with the cholesterol-AD hypothesis. Cholesterol levels in serum/plasma and brain of AD patients do not support cholesterol as a causative factor in AD. Prospective studies on statins and AD have largely failed to show efficacy. Even the experimental data are open to interpretation given that it is well-established that modification of cholesterol levels has effects on multiple proteins, not only APP and Aβ. The purpose of this review, therefore, is to examine the above-mentioned issues and discuss the pros and cons of the cholesterol-AD hypothesis, and the involvement of other lipids in the mevalonate pathway, such as isoprenoids and oxysterols, in AD. PMID:24329875

  11. Food insecurity as a driver of obesity in humans: The insurance hypothesis.

    Science.gov (United States)

    Nettle, Daniel; Andrews, Clare; Bateson, Melissa

    2017-01-01

    Integrative explanations of why obesity is more prevalent in some sectors of the human population than others are lacking. Here, we outline and evaluate one candidate explanation, the insurance hypothesis (IH). The IH is rooted in adaptive evolutionary thinking: The function of storing fat is to provide a buffer against shortfall in the food supply. Thus, individuals should store more fat when they receive cues that access to food is uncertain. Applied to humans, this implies that an important proximate driver of obesity should be food insecurity rather than food abundance per se. We integrate several distinct lines of theory and evidence that bear on this hypothesis. We present a theoretical model that shows it is optimal to store more fat when food access is uncertain, and we review the experimental literature from non-human animals showing that fat reserves increase when access to food is restricted. We provide a meta-analysis of 125 epidemiological studies of the association between perceived food insecurity and high body weight in humans. There is a robust positive association, but it is restricted to adult women in high-income countries. We explore why this could be in light of the IH and our theoretical model. We conclude that although the IH alone cannot explain the distribution of obesity in the human population, it may represent a very important component of a pluralistic explanation. We also discuss insights it may offer into the developmental origins of obesity, dieting-induced weight gain, and anorexia nervosa.

  12. Environmental policy without costs? A review of the Porter hypothesis

    Energy Technology Data Exchange (ETDEWEB)

    Braennlund, Runar; Lundgren, Tommy. e-mail: runar.brannlund@econ.umu.se

    2009-03-15

    This paper reviews the theoretical and empirical literature connected to the so called Porter Hypothesis. That is, to review the literature connected to the discussion about the relation between environmental policy and competitiveness. According to the conventional wisdom environmental policy, aiming for improving the environment through for example emission reductions, do imply costs since scarce resources must be diverted from somewhere else. However, this conventional wisdom has been challenged and questioned recently through what has been denoted the 'Porter hypothesis'. Those in the forefront of the Porter hypothesis challenge the conventional wisdom basically on the ground that resources are used inefficiently in the absence of the right kind of environmental regulations, and that the conventional neo-classical view is too static to take inefficiencies into account. The conclusions that can be made from this review is (1) that the theoretical literature can identify the circumstances and mechanisms that must exist for a Porter effect to occur, (2) that these circumstances are rather non-general, hence rejecting the Porter hypothesis in general, (3) that the empirical literature give no general support for the Porter hypothesis. Furthermore, a closer look at the 'Swedish case' reveals no support for the Porter hypothesis in spite of the fact that Swedish environmental policy the last 15-20 years seems to be in line the prerequisites stated by the Porter hypothesis concerning environmental policy

  13. Transitional issues

    International Nuclear Information System (INIS)

    1998-01-01

    This discussion paper, the fifth in the series developed at the IPPSO Market Design Conference, addressed the issue of the need to prevent Ontario Hydro from taking unfair advantage of independent producers and other stakeholders through activities and investments in new power generating capacity in the transitional period leading up to deregulation. The need for controls is predicated on the assumption that the short-term actions and investments of Ontario Hydro could seriously compromise the position of independent generators, and that without such controls the level playing field essential to the operation of a competitive market, does not exist. Various actual and potential actions of Ontario Hydro were discussed, all of which point to the need for strict controls over Ontario Hydro exercising its dominant market power in an unfair way. It was recommended that as a minimum, the provincial government should no longer provide guarantees for Ontario Hydro capital projects, and that Ontario Hydro be instructed to defer any investment on new or returning generating capacity until the new market is in place. Limits could also be placed on Ontario Hydro's marketing efforts to enter into contracts during the transition period, and Ontario Hydro and municipal utilities should be required to keep separate accounts of their commercial preparation, and to settle such accounts separate from ratepayer revenue

  14. The linear hypothesis - an idea whose time has passed

    International Nuclear Information System (INIS)

    Tschaeche, A.N.

    1995-01-01

    The linear no-threshold hypothesis is the basis for radiation protection standards in the United States. In the words of the National Council on Radiation Protection and Measurements (NCRP), the hypothesis is: open-quotes In the interest of estimating effects in humans conservatively, it is not unreasonable to follow the assumption of a linear relationship between dose and effect in the low dose regions for which direct observational data are not available.close quotes The International Commission on Radiological Protection (ICRP) stated the hypothesis in a slightly different manner: open-quotes One such basic assumption ... is that ... there is ... a linear relationship without threshold between dose and the probability of an effect. The hypothesis was necessary 50 yr ago when it was first enunciated because the dose-effect curve for ionizing radiation for effects in humans was not known. The ICRP and NCRP needed a model to extrapolate high-dose effects to low-dose effects. So the linear no-threshold hypothesis was born. Certain details of the history of the development and use of the linear hypothesis are presented. In particular, use of the hypothesis by the U.S. regulatory agencies is examined. Over time, the sense of the hypothesis has been corrupted. The corruption of the hypothesis into the current paradigm of open-quote a little radiation, no matter how small, can and will harm youclose quotes is presented. The reasons the corruption occurred are proposed. The effects of the corruption are enumerated, specifically, the use of the corruption by the antinuclear forces in the United States and some of the huge costs to U.S. taxpayers due to the corruption. An alternative basis for radiation protection standards to assure public safety, based on the weight of scientific evidence on radiation health effects, is proposed

  15. Development and application of Human Genome Epidemiology

    Science.gov (United States)

    Xu, Jingwen

    2017-12-01

    Epidemiology is a science that studies distribution of diseases and health in population and its influencing factors, it also studies how to prevent and cure disease and promote health strategies and measures. Epidemiology has developed rapidly in recent years and it is an intercross subject with various other disciplines to form a series of branch disciplines such as Genetic epidemiology, molecular epidemiology, drug epidemiology and tumor epidemiology. With the implementation and completion of Human Genome Project (HGP), Human Genome Epidemiology (HuGE) has emerged at this historic moment. In this review, the development of Human Genome Epidemiology, research content, the construction and structure of relevant network, research standards, as well as the existing results and problems are briefly outlined.

  16. About the Epidemiology and Genomics Research Program

    Science.gov (United States)

    Epidemiology is the scientific study of the causes and distribution of disease in populations. NCI-funded epidemiology research is conducted through research at institutions in the United States and internationally.

  17. Mitochondrial DNA and Cancer Epidemiology Workshop

    Science.gov (United States)

    A workshop to review the state-of-the science in the mitochondrial DNA field and its use in cancer epidemiology, and to develop a concept for a research initiative on mitochondrial DNA and cancer epidemiology.

  18. Biostatistics series module 2: Overview of hypothesis testing

    Directory of Open Access Journals (Sweden)

    Avijit Hazra

    2016-01-01

    Full Text Available Hypothesis testing (or statistical inference is one of the major applications of biostatistics. Much of medical research begins with a research question that can be framed as a hypothesis. Inferential statistics begins with a null hypothesis that reflects the conservative position of no change or no difference in comparison to baseline or between groups. Usually, the researcher has reason to believe that there is some effect or some difference which is the alternative hypothesis. The researcher therefore proceeds to study samples and measure outcomes in the hope of generating evidence strong enough for the statistician to be able to reject the null hypothesis. The concept of the P value is almost universally used in hypothesis testing. It denotes the probability of obtaining by chance a result at least as extreme as that observed, even when the null hypothesis is true and no real difference exists. Usually, if P is < 0.05 the null hypothesis is rejected and sample results are deemed statistically significant. With the increasing availability of computers and access to specialized statistical software, the drudgery involved in statistical calculations is now a thing of the past, once the learning curve of the software has been traversed. The life sciences researcher is therefore free to devote oneself to optimally designing the study, carefully selecting the hypothesis tests to be applied, and taking care in conducting the study well. Unfortunately, selecting the right test seems difficult initially. Thinking of the research hypothesis as addressing one of five generic research questions helps in selection of the right hypothesis test. In addition, it is important to be clear about the nature of the variables (e.g., numerical vs. categorical; parametric vs. nonparametric and the number of groups or data sets being compared (e.g., two or more than two at a time. The same research question may be explored by more than one type of hypothesis test

  19. Corporate governance cycles during transition

    DEFF Research Database (Denmark)

    Mygind, Niels; Demina, Natalia; Gregoric, Aleksandra

    2004-01-01

    -ing or exit stage. During transition the cycle reflects: privatization often with a high proportion of employee ownership like in Russia and in Slovenia; strong pressures for restructuring and owner-ship changes; limited possibility for external finance because of embryonic development of the fi......-nancial system. To provide simple hypothesis tests, we use Russian enterprise data for 1995-2003 and Slovenian data covering 1998-2003. In spite of differences in institutional development, con-cerning privatization and development of corporate governance institutions, we find that govern-ance cycles are broadly...... of ownership on managers, external domestic and foreign owners. JEL-codes: G3, J5, P2, P3 - Keywords: corporate governance, life-cycle, privatization, ownership change, transition economies, Russia and Slovenia....

  20. The evolving epidemiology of inflammatory bowel disease.

    LENUS (Irish Health Repository)

    Shanahan, Fergus

    2009-07-01

    Epidemiologic studies in inflammatory bowel disease (IBD) include assessments of disease burden and evolving patterns of disease presentation. Although it is hoped that sound epidemiologic studies provide aetiological clues, traditional risk factor-based epidemiology has provided limited insights into either Crohn\\'s disease or ulcerative colitis etiopathogenesis. In this update, we will summarize how the changing epidemiology of IBD associated with modernization can be reconciled with current concepts of disease mechanisms and will discuss studies of clinically significant comorbidity in IBD.

  1. Wastewater-based epidemiology, an analytical chemical approach for the investigation of human consumption of lifestyle chemicals

    NARCIS (Netherlands)

    Causanilles Llanes, A.

    2018-01-01

    The research presented in this thesis supports the hypothesis that wastewater-based epidemiology (WBE) approach can be used as an alternative and non-intrusive technique that provides information about a population’s health and lifestyle habits. The focus is in the essential role of analytical

  2. An adaptive workspace hypothesis about the neural correlates of consciousness: insights from neuroscience and meditation studies.

    Science.gov (United States)

    Raffone, Antonino; Srinivasan, Narayanan

    2009-01-01

    While enormous progress has been made to identify neural correlates of consciousness (NCC), crucial NCC aspects are still very controversial. A major hurdle is the lack of an adequate definition and characterization of different aspects of conscious experience and also its relationship to attention and metacognitive processes like monitoring. In this paper, we therefore attempt to develop a unitary theoretical framework for NCC, with an interdependent characterization of endogenous attention, access consciousness, phenomenal awareness, metacognitive consciousness, and a non-referential form of unified consciousness. We advance an adaptive workspace hypothesis about the NCC based on the global workspace model emphasizing transient resonant neurodynamics and prefrontal cortex function, as well as meditation-related characterizations of conscious experiences. In this hypothesis, transient dynamic links within an adaptive coding net in prefrontal cortex, especially in anterior prefrontal cortex, and between it and the rest of the brain, in terms of ongoing intrinsic and long-range signal exchanges, flexibly regulate the interplay between endogenous attention, access consciousness, phenomenal awareness, and metacognitive consciousness processes. Such processes are established in terms of complementary aspects of an ongoing transition between context-sensitive global workspace assemblies, modulated moment-to-moment by body and environment states. Brain regions associated to momentary interoceptive and exteroceptive self-awareness, or first-person experiential perspective as emphasized in open monitoring meditation, play an important modulatory role in adaptive workspace transitions.

  3. History and philosophy of modern epidemiology

    DEFF Research Database (Denmark)

    Andersen, Hanne

    2012-01-01

    Epidemiological studies of chronic diseases began around the mid-20th century. Contrary to the infectious disease epidemiology which had prevailed at the beginning of the 20th century and which had focused on single agents causing individual diseases, the chronic disease epidemiology which emerge...

  4. Validity of the Generalized Brink-Axel Hypothesis in (238)Np.

    Science.gov (United States)

    Guttormsen, M; Larsen, A C; Görgen, A; Renstrøm, T; Siem, S; Tornyi, T G; Tveten, G M

    2016-01-08

    We analyze primary γ-ray spectra of the odd-odd (238)Np nucleus extracted from (237)Np(d,pγ)(238)Np coincidence data measured at the Oslo Cyclotron Laboratory. The primary γ spectra cover an excitation-energy region of 0≤E(I)≤5.4  MeV, and allow us to perform a detailed study of the γ-ray strength as a function of excitation energy. Hence, we can test the validity of the generalized Brink-Axel hypothesis, which, in its strictest form, claims no excitation-energy dependence on the γ strength. In this work, using the available high-quality (238)Np data, we show that the γ-ray strength function is to a very large extent independent of the initial and final states. Thus, for the first time, the generalized Brink-Axel hypothesis is experimentally verified for γ transitions between states in the quasicontinuum region, not only for specific collective resonances, but also for the full strength below the neutron separation energy. Based on our findings, the necessary criteria for the generalized Brink-Axel hypothesis to be fulfilled are outlined.

  5. Energy transition

    International Nuclear Information System (INIS)

    Anon.

    2013-01-01

    The yearly environmental conference will hold on September 2013 to evaluate the negotiations led at the national and local levels for december 2012. The government will have then to decide of an energy programming bill which will be submitted to the Parliament at the beginning of the year 2014. 30 main propositions have emerged of the decentralised debates. One of them is the ecological taxation which raise the question of the gas oil and petrol taxation. The current environmental taxes are for almost three quarters of them taxes on energy consumptions and mainly on fossil energies. The Economic, Social and Environmental Council, gives his opinion on the way to find resources to ensure the ecological and energy transition while reducing the public deficit of the State. (O.M.)

  6. Null but not void: considerations for hypothesis testing.

    Science.gov (United States)

    Shaw, Pamela A; Proschan, Michael A

    2013-01-30

    Standard statistical theory teaches us that once the null and alternative hypotheses have been defined for a parameter, the choice of the statistical test is clear. Standard theory does not teach us how to choose the null or alternative hypothesis appropriate to the scientific question of interest. Neither does it tell us that in some cases, depending on which alternatives are realistic, we may want to define our null hypothesis differently. Problems in statistical practice are frequently not as pristinely summarized as the classic theory in our textbooks. In this article, we present examples in statistical hypothesis testing in which seemingly simple choices are in fact rich with nuance that, when given full consideration, make the choice of the right hypothesis test much less straightforward. Published 2012. This article is a US Government work and is in the public domain in the USA.

  7. Cross-system log file analysis for hypothesis testing

    NARCIS (Netherlands)

    Glahn, Christian

    2008-01-01

    Glahn, C. (2008). Cross-system log file analysis for hypothesis testing. Presented at Empowering Learners for Lifelong Competence Development: pedagogical, organisational and technological issues. 4th TENCompetence Open Workshop. April, 10, 2008, Madrid, Spain.

  8. Hypothesis Testing Using the Films of the Three Stooges

    Science.gov (United States)

    Gardner, Robert; Davidson, Robert

    2010-01-01

    The use of The Three Stooges' films as a source of data in an introductory statistics class is described. The Stooges' films are separated into three populations. Using these populations, students may conduct hypothesis tests with data they collect.

  9. Incidence of allergy and atopic disorders and hygiene hypothesis.

    Czech Academy of Sciences Publication Activity Database

    Bencko, V.; Šíma, Petr

    2017-01-01

    Roč. 2, 6 March (2017), č. článku 1244. ISSN 2474-1663 Institutional support: RVO:61388971 Keywords : allergy disorders * atopic disorders * hygiene hypothesis Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology

  10. The Double-Deficit Hypothesis in Spanish Developmental Dyslexia

    Science.gov (United States)

    Jimenez, Juan E.; Hernandez-Valle, Isabel; Rodriguez, Cristina; Guzman, Remedios; Diaz, Alicia; Ortiz, Rosario

    2008-01-01

    The double-deficit hypothesis (DDH) of developmental dyslexia was investigated in seven to twelve year old Spanish children. It was observed that the double deficit (DD) group had the greatest difficulty with reading.

  11. The Random-Walk Hypothesis on the Indian Stock Market

    OpenAIRE

    Ankita Mishra; Vinod Mishra; Russell Smyth

    2014-01-01

    This study tests the random walk hypothesis for the Indian stock market. Using 19 years of monthly data on six indices from the National Stock Exchange (NSE) and the Bombay Stock Exchange (BSE), this study applies three different unit root tests with two structural breaks to analyse the random walk hypothesis. We find that unit root tests that allow for two structural breaks alone are not able to reject the unit root null; however, a recently developed unit root test that simultaneously accou...

  12. The Fractal Market Hypothesis: Applications to Financial Forecasting

    OpenAIRE

    Blackledge, Jonathan

    2010-01-01

    Most financial modelling systems rely on an underlying hypothesis known as the Efficient Market Hypothesis (EMH) including the famous Black-Scholes formula for placing an option. However, the EMH has a fundamental flaw: it is based on the assumption that economic processes are normally distributed and it has long been known that this is not the case. This fundamental assumption leads to a number of shortcomings associated with using the EMH to analyse financial data which includes failure to ...

  13. Dopamine and Reward: The Anhedonia Hypothesis 30 years on

    OpenAIRE

    Wise, Roy A.

    2008-01-01

    The anhedonia hypothesis – that brain dopamine plays a critical role in the subjective pleasure associated with positive rewards – was intended to draw the attention of psychiatrists to the growing evidence that dopamine plays a critical role in the objective reinforcement and incentive motivation associated with food and water, brain stimulation reward, and psychomotor stimulant and opiate reward. The hypothesis called to attention the apparent paradox that neuroleptics, drugs used to treat ...

  14. Testing the null hypothesis: the forgotten legacy of Karl Popper?

    Science.gov (United States)

    Wilkinson, Mick

    2013-01-01

    Testing of the null hypothesis is a fundamental aspect of the scientific method and has its basis in the falsification theory of Karl Popper. Null hypothesis testing makes use of deductive reasoning to ensure that the truth of conclusions is irrefutable. In contrast, attempting to demonstrate the new facts on the basis of testing the experimental or research hypothesis makes use of inductive reasoning and is prone to the problem of the Uniformity of Nature assumption described by David Hume in the eighteenth century. Despite this issue and the well documented solution provided by Popper's falsification theory, the majority of publications are still written such that they suggest the research hypothesis is being tested. This is contrary to accepted scientific convention and possibly highlights a poor understanding of the application of conventional significance-based data analysis approaches. Our work should remain driven by conjecture and attempted falsification such that it is always the null hypothesis that is tested. The write up of our studies should make it clear that we are indeed testing the null hypothesis and conforming to the established and accepted philosophical conventions of the scientific method.

  15. Local health department epidemiologic capacity: a stratified cross-sectional assessment describing the quantity, education, training, and perceived competencies of epidemiologic staff.

    Science.gov (United States)

    O'Keefe, Kaitlin A; Shafir, Shira C; Shoaf, Kimberley I

    2013-01-01

    Local health departments (LHDs) must have sufficient numbers of staff functioning in an epidemiologic role with proper education, training, and skills to protect the health of communities they serve. This pilot study was designed to describe the composition, training, and competency level of LHD staff and examine the hypothesis that potential disparities exist between LHDs serving different sized populations. Cross-sectional surveys were conducted with directors and epidemiologic staff from a sample of 100 LHDs serving jurisdictions of varied sizes. Questionnaires included inquiries regarding staff composition, education, training, and measures of competency modeled on previously conducted studies by the Council of State and Territorial Epidemiologists. Number of epidemiologic staff, academic degree distribution, epidemiologic training, and both director and staff confidence in task competencies were calculated for each LHD size strata. Disparities in measurements were observed in LHDs serving different sized populations. LHDs serving small populations reported a smaller average number of epidemiologic staff than those serving larger jurisdictions. As size of population served increased, percentages of staff and directors holding bachelors' and masters' degrees increased, while those holding RN degrees decreased. A higher degree of perceived competency of staff in most task categories was reported in LHDs serving larger populations. LHDs serving smaller populations reported fewer epidemiologic staff, therefore might benefit from additional resources. Differences observed in staff education, training, and competencies suggest that enhanced epidemiologic training might be particularly needed in LHDs serving smaller populations. RESULTS can be used as a baseline for future research aimed at identifying areas where training and personnel resources might be particularly needed to increase the capabilities of LHDs.

  16. Coronary heart disease mortality in China: age, gender, and urban-rural gaps during epidemiological transition Mortalidad por cardiopatía coronaria en China: edad, sexo y brechas entre la población urbana y la rural durante la transición epidemiológica

    Directory of Open Access Journals (Sweden)

    Guohong Jiang

    2012-04-01

    Full Text Available OBJECTIVE: To examine and describe coronary heart disease (CHD mortality and its pattern of change (trend by sex, age, and area of residence (urban versus rural in Tianjin, China, within the context of epidemiological transition, and compare it with current trends in the Americas and Europe. METHODS: A total of 104 393 cases of CHD death in Tianjin occurring between 1999 and 2008 were monitored. Death due to CHD was coded using International Classification of Diseases (ICD standards (ninth and tenth revisions. Standardized CHD mortality rates and their trends were analyzed by age, sex, and urban versus rural residence. RESULTS: During the 10-year study period, the proportion of total deaths due to CHD in Tianjin increased significantly (from 16% to 24% and age-standardized CHD mortality increased slightly (with no statistical differences, in contrast to CHD mortality trends in various countries in the Americas and Europe, which are declining. No difference was found in Tianjin's CHD mortality trend by sex. Overall CHD mortality was consistently higher among older age groups, males, and residents of urban areas. The proportion of CHD deaths occurring outside hospitals was 55.81%, with a declining trend over the study period. Rural areas had a higher proportion of outside-hospital CHD mortality than urban areas, but no difference was found across age groups. CONCLUSIONS: From 1999 to 2008, CHD mortality in Tianjin varied by sex, age, and urban versus rural area of residence. Future research to identify CHD risk factors and the populations most vulnerable to the disease is recommended to help strengthen CHD prevention. Strategies for CHD control similar to those used in various developed countries in the Americas and Europe should be developed to reduce the CHD burden in China.OBJETIVO: Examinar y describir la mortalidad por cardiopatía coronaria y su patrón de cambio (tendencia por sexo, edad y zona de residencia (urbana frente a rural en Tianj

  17. Epidemiology of subtypes of depression

    DEFF Research Database (Denmark)

    Kessing, L V

    2007-01-01

    depression, dysthymia, and subsyndromal states; the association between stressful life events and depression appears to diminish with the number of depressive episodes. Finally, recent genetic findings are congruent with a model indicating that the majority of depressions develop in the interplay between...... genes and stressful experiences, whereas 'reactive' depressions and 'endogenous' depressions apparently exist at a lower prevalence. CONCLUSION: Further longitudinal, analytical, and genetic epidemiologic studies are needed to reveal which conditions are mild and transient, and which may be precursors......OBJECTIVE: There is a general clinical impression that depression differs qualitatively from non-depressive conditions, and that it can be identified as a categorical entity. In contrast, epidemiological studies support the view that depression is dynamic in nature and develops on a continuous...

  18. "Epidemiological criminology": coming full circle.

    Science.gov (United States)

    Akers, Timothy A; Lanier, Mark M

    2009-03-01

    Members of the public health and criminal justice disciplines often work with marginalized populations: people at high risk of drug use, health problems, incarceration, and other difficulties. As these fields increasingly overlap, distinctions between them are blurred, as numerous research reports and funding trends document. However, explicit theoretical and methodological linkages between the 2 disciplines remain rare. A new paradigm that links methods and statistical models of public health with those of their criminal justice counterparts is needed, as are increased linkages between epidemiological analogies, theories, and models and the corresponding tools of criminology. We outline disciplinary commonalities and distinctions, present policy examples that integrate similarities, and propose "epidemiological criminology" as a bridging framework.

  19. Viral marketing as epidemiological model

    OpenAIRE

    Rodrigues, Helena Sofia; Fonseca, Manuel

    2015-01-01

    In epidemiology, an epidemic is defined as the spread of an infectious disease to a large number of people in a given population within a short period of time. In the marketing context, a message is viral when it is broadly sent and received by the target market through person-to-person transmission. This specific marketing communication strategy is commonly referred as viral marketing. Due to this similarity between an epidemic and the viral marketing process and because the understanding of...

  20. Epidemiologic perspectives in radiation carcinogenesis

    International Nuclear Information System (INIS)

    Jablon, S.

    1984-01-01

    Epidemiological studies can tell much about carcinogenic effects at large doses, but not at small. To embark on large, long-term, expensive follow-up studies to learn something of scientific value about the effects of low doses-an average of three rads, say - is to waste time, effort, and money. It would be a fruitless effort even if the only problem to overcome was sampling variability - but it is not

  1. EPIDEMIOLOGICAL EVALUATION OF COLORECTAL CANCER

    OpenAIRE

    B. Shafayan M. Keyhani

    2003-01-01

    This study was carried out to analyze certain epidemiological variations in Iranian patients with colorectal cancer. (CRC): From March 1981 up to March 1993, 103 patients were analyzed retrospectively for age, gender, marital state, job, nutritional habits, presenting symptoms and histopathological features. Most of the patients with colorectal cancer were male, age range 20-75 (mean 56), 25.4 percent were long-term smokers and bleeding was the most common symptom. The rectum was the most com...

  2. Causal diagrams in systems epidemiology

    Directory of Open Access Journals (Sweden)

    Joffe Michael

    2012-03-01

    Full Text Available Abstract Methods of diagrammatic modelling have been greatly developed in the past two decades. Outside the context of infectious diseases, systematic use of diagrams in epidemiology has been mainly confined to the analysis of a single link: that between a disease outcome and its proximal determinant(s. Transmitted causes ("causes of causes" tend not to be systematically analysed. The infectious disease epidemiology modelling tradition models the human population in its environment, typically with the exposure-health relationship and the determinants of exposure being considered at individual and group/ecological levels, respectively. Some properties of the resulting systems are quite general, and are seen in unrelated contexts such as biochemical pathways. Confining analysis to a single link misses the opportunity to discover such properties. The structure of a causal diagram is derived from knowledge about how the world works, as well as from statistical evidence. A single diagram can be used to characterise a whole research area, not just a single analysis - although this depends on the degree of consistency of the causal relationships between different populations - and can therefore be used to integrate multiple datasets. Additional advantages of system-wide models include: the use of instrumental variables - now emerging as an important technique in epidemiology in the context of mendelian randomisation, but under-used in the exploitation of "natural experiments"; the explicit use of change models, which have advantages with respect to inferring causation; and in the detection and elucidation of feedback.

  3. Causal diagrams in systems epidemiology.

    Science.gov (United States)

    Joffe, Michael; Gambhir, Manoj; Chadeau-Hyam, Marc; Vineis, Paolo

    2012-03-19

    Methods of diagrammatic modelling have been greatly developed in the past two decades. Outside the context of infectious diseases, systematic use of diagrams in epidemiology has been mainly confined to the analysis of a single link: that between a disease outcome and its proximal determinant(s). Transmitted causes ("causes of causes") tend not to be systematically analysed.The infectious disease epidemiology modelling tradition models the human population in its environment, typically with the exposure-health relationship and the determinants of exposure being considered at individual and group/ecological levels, respectively. Some properties of the resulting systems are quite general, and are seen in unrelated contexts such as biochemical pathways. Confining analysis to a single link misses the opportunity to discover such properties.The structure of a causal diagram is derived from knowledge about how the world works, as well as from statistical evidence. A single diagram can be used to characterise a whole research area, not just a single analysis - although this depends on the degree of consistency of the causal relationships between different populations - and can therefore be used to integrate multiple datasets.Additional advantages of system-wide models include: the use of instrumental variables - now emerging as an important technique in epidemiology in the context of mendelian randomisation, but under-used in the exploitation of "natural experiments"; the explicit use of change models, which have advantages with respect to inferring causation; and in the detection and elucidation of feedback.

  4. Biomarkers in Prostate Cancer Epidemiology

    Directory of Open Access Journals (Sweden)

    Mudit Verma

    2011-09-01

    Full Text Available Understanding the etiology of a disease such as prostate cancer may help in identifying populations at high risk, timely intervention of the disease, and proper treatment. Biomarkers, along with exposure history and clinical data, are useful tools to achieve these goals. Individual risk and population incidence of prostate cancer result from the intervention of genetic susceptibility and exposure. Biochemical, epigenetic, genetic, and imaging biomarkers are used to identify people at high risk for developing prostate cancer. In cancer epidemiology, epigenetic biomarkers offer advantages over other types of biomarkers because they are expressed against a person’s genetic background and environmental exposure, and because abnormal events occur early in cancer development, which includes several epigenetic alterations in cancer cells. This article describes different biomarkers that have potential use in studying the epidemiology of prostate cancer. We also discuss the characteristics of an ideal biomarker for prostate cancer, and technologies utilized for biomarker assays. Among epigenetic biomarkers, most reports indicate GSTP1 hypermethylation as the diagnostic marker for prostate cancer; however, NKX2-5, CLSTN1, SPOCK2, SLC16A12, DPYS, and NSE1 also have been reported to be regulated by methylation mechanisms in prostate cancer. Current challenges in utilization of biomarkers in prostate cancer diagnosis and epidemiologic studies and potential solutions also are discussed.

  5. Panel 1: Epidemiology and Diagnosis.

    Science.gov (United States)

    Homøe, Preben; Kværner, Kari; Casey, Janet R; Damoiseaux, Roger A M J; van Dongen, Thijs M A; Gunasekera, Hasantha; Jensen, Ramon G; Kvestad, Ellen; Morris, Peter S; Weinreich, Heather M

    2017-04-01

    Objective To create a literature review between 2011 and June 1, 2015, on advances in otitis media (OM) epidemiology and diagnosis (including relevant audiology studies). Data Sources Electronic search engines (PubMed, EMBASE, and Cochrane Library) with a predefined search strategy. Review Methods Articles with appropriate epidemiologic methodology for OM, including acute mastoiditis and eustachian tube dysfunction. Items included OM worldwide and in high-risk populations, OM-related hearing loss, news in OM diagnostics, prenatal risk factors and comorbidities, postnatal risk factors, genetics, microbiological epidemiology, guidelines, and quality of life. Conclusions Diagnostic evidence and genetic studies are increasing; guidelines are introduced worldwide; and there is evidence of benefit of pneumococcal conjugate vaccines. New risk factors and comordities are identified in the study period, and quality of life is affected in children and their families. Implications for Practice Chronic suppurative OM occurs worldwide and contributes to lifelong hearing loss. Uniform definitions are still lacking and should be provided. An association between HIV and chronic suppurative OM has been found. Tympanometry is recommended for diagnosis, with or without pneumatic otoscopy. Video otoscopy, algorithms, and validated questionnaires may assist clinicians. Childhood obesity is associated with OM. Heritability accounts for 20% to 50% of OM diagnoses. OM-prone children seem to produce weaker immunologic responses to pneumococcal conjugate vaccines. Clinicians tend to individualize treatment without adhering to guidelines.

  6. Which transition comes first? Urban and demographic transitions in Belgium and Sweden

    Directory of Open Access Journals (Sweden)

    Philippe Bocquier

    2015-12-01

    Full Text Available Background: Several theories compete to explain the main drivers of urbanisation, past and present, in relation to both demographic transition and economic development. One hypothesis is that rural-to-urban migration is the driver of urbanisation; another is that urban mortality decline actually triggered urban transition. Objective: This paper reconsiders the relationship between demographic (vital migration and urban transitions by analysing the long-term contribution of natural and migratory movements to urban transition. The respective contributions of birth, death, and migration and their timing will indicate whether economic development, through labour force migration, or vital transition mainly determines urban transition. Methods: After examining the spatial dimension of the demographic transition theory, we use 19th and 20th century series on Sweden and Belgium to better identify the migration component of urban transition through the computation of growth difference between urban and rural areas, accounting for the often neglected reclassification effect. Results: In both Sweden and Belgium, migration is the direct or indirect (through reclassification engine of urban transition and its contribution precedes the onset of vital transition, while the vital transition has a secondary, unstable, and negative role in the urban transition. Conclusions: Changes in the economic sphere are reinstated as the underlying cause of population change, acting through the shift of human capital in space. Methodological consequences are then drawn for analysing vital and urban transitions in an increasingly interdependent world. Contribution: The paper contributes to the theoretical literature on urban and demographic transitions in relation to economic development. The proposed method evaluates migration contribution without having to measure it.

  7. Epidemiological correlates of breast cancer in South India.

    Science.gov (United States)

    Babu, Giridhara Rathnaiah; Lakshmi, Srikanthi Bodapati; Thiyagarajan, Jotheeswaran Amuthavalli

    2013-01-01

    Breast cancer is the most frequent cancer in women globally and represents the second leading cause of cancer death among women (after lung cancer). India is going through epidemiologic transition. It is reported that the incidence of breast cancer is rising rapidly as a result of changes in reproductive risk factors, dietary habits and increasing life expectancy, acting in concert with genetic factors. In order to understand the existing epidemiological correlates of breast cancer in South India, a systematic review of evidence available on epidemiologic correlates of breast cancer addressing incidence, prevalence, and associated factors like age, reproductive factors, cultural and religious factors was performed with specific focus on screening procedures in southern India. An increase in breast cancer incidence due to various modifiable risk factors was noted, especially in women over 40 years of age, with late stage of presentation, lack of awareness about screening, costs, fear and stigma associated with the disease serving as major barriers for early presentation. Educational strategies should be aimed at modifying the life style, early planning of pregnancy, promoting breast feeding and physical activity. It is very important to obtain reliable data for planning policies, decision-making and setting up the priorities.

  8. Low-energy effective models for two-flavor quantum chromodynamics and the universality hypothesis

    International Nuclear Information System (INIS)

    Grahl, Mara

    2014-01-01

    Our thesis is centered around the question of which order the chiral phase transition of two-flavor QCD is. First of all we outline several general aspects of phase transitions which are of central importance for the understanding of the RG approach towards them. Our focus lies on reviewing the universality hypothesis, a crucial ingredient when it comes to the construction of effective theories for order parameters, the credibility of which often heavily depends on universality arguments. We finish the chapter with an attempt to formulate the latter more precisely than usually done. The next chapter discusses the chiral phase transition from a general point of view. We supplement well-known facts with a detailed discussion of the so-called O(4) conjecture. Thereafter we introduce the nonperturbative method we use, the FRG method. Furthermore, we discuss the relation between effective models for QCD and the underlying fundamental theory making use of the FRG perspective. The next chapter is concerned with a mathematical subject indispensable for our approach towards the study of phase transitions, namely the systematic construction of polynomial invariants characterizing a given symmetry. With this thesis we point out its relevance in the context of high-energy physics. We present a simple, but novel, brute-force algorithm to effectively construct invariants of a given polynomial order. The next chapter is devoted to RG studies of several dimensionally reduced theories which are capable to either predict or to rule out the possible existence of a second-order phase transition. Of main interest for us is the linear sigma model, particularly in presence of the axial anomaly. It turns out that the fixed-point structure of the latter is rather complicated, requiring a deeper understanding of the underlying method and its preconditions. This leads us to a careful analysis of the fixed-point structure of several models, which is of great benefit for our review of the

  9. A large scale test of the gaming-enhancement hypothesis

    Directory of Open Access Journals (Sweden)

    Andrew K. Przybylski

    2016-11-01

    Full Text Available A growing research literature suggests that regular electronic game play and game-based training programs may confer practically significant benefits to cognitive functioning. Most evidence supporting this idea, the gaming-enhancement hypothesis, has been collected in small-scale studies of university students and older adults. This research investigated the hypothesis in a general way with a large sample of 1,847 school-aged children. Our aim was to examine the relations between young people’s gaming experiences and an objective test of reasoning performance. Using a Bayesian hypothesis testing approach, evidence for the gaming-enhancement and null hypotheses were compared. Results provided no substantive evidence supporting the idea that having preference for or regularly playing commercially available games was positively associated with reasoning ability. Evidence ranged from equivocal to very strong in support for the null hypothesis over what was predicted. The discussion focuses on the value of Bayesian hypothesis testing for investigating electronic gaming effects, the importance of open science practices, and pre-registered designs to improve the quality of future work.

  10. A large scale test of the gaming-enhancement hypothesis.

    Science.gov (United States)

    Przybylski, Andrew K; Wang, John C

    2016-01-01

    A growing research literature suggests that regular electronic game play and game-based training programs may confer practically significant benefits to cognitive functioning. Most evidence supporting this idea, the gaming-enhancement hypothesis , has been collected in small-scale studies of university students and older adults. This research investigated the hypothesis in a general way with a large sample of 1,847 school-aged children. Our aim was to examine the relations between young people's gaming experiences and an objective test of reasoning performance. Using a Bayesian hypothesis testing approach, evidence for the gaming-enhancement and null hypotheses were compared. Results provided no substantive evidence supporting the idea that having preference for or regularly playing commercially available games was positively associated with reasoning ability. Evidence ranged from equivocal to very strong in support for the null hypothesis over what was predicted. The discussion focuses on the value of Bayesian hypothesis testing for investigating electronic gaming effects, the importance of open science practices, and pre-registered designs to improve the quality of future work.

  11. Investigating the environmental Kuznets curve hypothesis in Vietnam

    International Nuclear Information System (INIS)

    Al-Mulali, Usama; Saboori, Behnaz; Ozturk, Ilhan

    2015-01-01

    This study investigates the existence of the environmental Kuznets curve (EKC) hypothesis in Vietnam during the period 1981–2011. To realize the goals of this study, a pollution model was established applying the Autoregressive Distributed Lag (ARDL) methodology. The results revealed that the pollution haven hypothesis does exist in Vietnam because capital increases pollution. In addition, imports also increase pollution which indicates that most of Vietnam's imported products are energy intensive and highly polluted. However, exports have no effect on pollution which indicates that the level of exports is not significant enough to affect pollution. Moreover, fossil fuel energy consumption increases pollution while renewable energy consumption has no significant effect in reducing pollution. Furthermore, labor force reduces pollution since most of Vietnam's labor force is in the agricultural and services sectors which are less energy intensive than the industrial sector. Based on the obtained results, the EKC hypothesis does not exist because the relationship between GDP and pollution is positive in both the short and long run. - Highlights: • The environmental Kuznets curve (EKC) hypothesis in Vietnam is investigated. • The Autoregressive Distributed Lag (ARDL) methodology was utilized. • The EKC hypothesis does not exist

  12. Social learning and evolution: the cultural intelligence hypothesis

    Science.gov (United States)

    van Schaik, Carel P.; Burkart, Judith M.

    2011-01-01

    If social learning is more efficient than independent individual exploration, animals should learn vital cultural skills exclusively, and routine skills faster, through social learning, provided they actually use social learning preferentially. Animals with opportunities for social learning indeed do so. Moreover, more frequent opportunities for social learning should boost an individual's repertoire of learned skills. This prediction is confirmed by comparisons among wild great ape populations and by social deprivation and enculturation experiments. These findings shaped the cultural intelligence hypothesis, which complements the traditional benefit hypotheses for the evolution of intelligence by specifying the conditions in which these benefits can be reaped. The evolutionary version of the hypothesis argues that species with frequent opportunities for social learning should more readily respond to selection for a greater number of learned skills. Because improved social learning also improves asocial learning, the hypothesis predicts a positive interspecific correlation between social-learning performance and individual learning ability. Variation among primates supports this prediction. The hypothesis also predicts that more heavily cultural species should be more intelligent. Preliminary tests involving birds and mammals support this prediction too. The cultural intelligence hypothesis can also account for the unusual cognitive abilities of humans, as well as our unique mechanisms of skill transfer. PMID:21357223

  13. Dopamine and reward: the anhedonia hypothesis 30 years on.

    Science.gov (United States)

    Wise, Roy A

    2008-10-01

    The anhedonia hypothesis--that brain dopamine plays a critical role in the subjective pleasure associated with positive rewards--was intended to draw the attention of psychiatrists to the growing evidence that dopamine plays a critical role in the objective reinforcement and incentive motivation associated with food and water, brain stimulation reward, and psychomotor stimulant and opiate reward. The hypothesis called to attention the apparent paradox that neuroleptics, drugs used to treat a condition involving anhedonia (schizophrenia), attenuated in laboratory animals the positive reinforcement that we normally associate with pleasure. The hypothesis held only brief interest for psychiatrists, who pointed out that the animal studies reflected acute actions of neuroleptics whereas the treatment of schizophrenia appears to result from neuroadaptations to chronic neuroleptic administration, and that it is the positive symptoms of schizophrenia that neuroleptics alleviate, rather than the negative symptoms that include anhedonia. Perhaps for these reasons, the hypothesis has had minimal impact in the psychiatric literature. Despite its limited heuristic value for the understanding of schizophrenia, however, the anhedonia hypothesis has had major impact on biological theories of reinforcement, motivation, and addiction. Brain dopamine plays a very important role in reinforcement of response habits, conditioned preferences, and synaptic plasticity in cellular models of learning and memory. The notion that dopamine plays a dominant role in reinforcement is fundamental to the psychomotor stimulant theory of addiction, to most neuroadaptation theories of addiction, and to current theories of conditioned reinforcement and reward prediction. Properly understood, it is also fundamental to recent theories of incentive motivation.

  14. Social learning and evolution: the cultural intelligence hypothesis.

    Science.gov (United States)

    van Schaik, Carel P; Burkart, Judith M

    2011-04-12

    If social learning is more efficient than independent individual exploration, animals should learn vital cultural skills exclusively, and routine skills faster, through social learning, provided they actually use social learning preferentially. Animals with opportunities for social learning indeed do so. Moreover, more frequent opportunities for social learning should boost an individual's repertoire of learned skills. This prediction is confirmed by comparisons among wild great ape populations and by social deprivation and enculturation experiments. These findings shaped the cultural intelligence hypothesis, which complements the traditional benefit hypotheses for the evolution of intelligence by specifying the conditions in which these benefits can be reaped. The evolutionary version of the hypothesis argues that species with frequent opportunities for social learning should more readily respond to selection for a greater number of learned skills. Because improved social learning also improves asocial learning, the hypothesis predicts a positive interspecific correlation between social-learning performance and individual learning ability. Variation among primates supports this prediction. The hypothesis also predicts that more heavily cultural species should be more intelligent. Preliminary tests involving birds and mammals support this prediction too. The cultural intelligence hypothesis can also account for the unusual cognitive abilities of humans, as well as our unique mechanisms of skill transfer.

  15. A comparator-hypothesis account of biased contingency detection.

    Science.gov (United States)

    Vadillo, Miguel A; Barberia, Itxaso

    2018-02-12

    Our ability to detect statistical dependencies between different events in the environment is strongly biased by the number of coincidences between them. Even when there is no true covariation between a cue and an outcome, if the marginal probability of either of them is high, people tend to perceive some degree of statistical contingency between both events. The present paper explores the ability of the Comparator Hypothesis to explain the general pattern of results observed in this literature. Our simulations show that this model can account for the biasing effects of the marginal probabilities of cues and outcomes. Furthermore, the overall fit of the Comparator Hypothesis to a sample of experimental conditions from previous studies is comparable to that of the popular Rescorla-Wagner model. These results should encourage researchers to further explore and put to the test the predictions of the Comparator Hypothesis in the domain of biased contingency detection. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. The large numbers hypothesis and a relativistic theory of gravitation

    International Nuclear Information System (INIS)

    Lau, Y.K.; Prokhovnik, S.J.

    1986-01-01

    A way to reconcile Dirac's large numbers hypothesis and Einstein's theory of gravitation was recently suggested by Lau (1985). It is characterized by the conjecture of a time-dependent cosmological term and gravitational term in Einstein's field equations. Motivated by this conjecture and the large numbers hypothesis, we formulate here a scalar-tensor theory in terms of an action principle. The cosmological term is required to be spatially dependent as well as time dependent in general. The theory developed is appled to a cosmological model compatible with the large numbers hypothesis. The time-dependent form of the cosmological term and the scalar potential are then deduced. A possible explanation of the smallness of the cosmological term is also given and the possible significance of the scalar field is speculated

  17. Universality hypothesis breakdown at one-loop order

    Science.gov (United States)

    Carvalho, P. R. S.

    2018-05-01

    We probe the universality hypothesis by analytically computing the at least two-loop corrections to the critical exponents for q -deformed O (N ) self-interacting λ ϕ4 scalar field theories through six distinct and independent field-theoretic renormalization group methods and ɛ -expansion techniques. We show that the effect of q deformation on the one-loop corrections to the q -deformed critical exponents is null, so the universality hypothesis is broken down at this loop order. Such an effect emerges only at the two-loop and higher levels, and the validity of the universality hypothesis is restored. The q -deformed critical exponents obtained through the six methods are the same and, furthermore, reduce to their nondeformed values in the appropriated limit.

  18. Unicorns do exist: a tutorial on "proving" the null hypothesis.

    Science.gov (United States)

    Streiner, David L

    2003-12-01

    Introductory statistics classes teach us that we can never prove the null hypothesis; all we can do is reject or fail to reject it. However, there are times when it is necessary to try to prove the nonexistence of a difference between groups. This most often happens within the context of comparing a new treatment against an established one and showing that the new intervention is not inferior to the standard. This article first outlines the logic of "noninferiority" testing by differentiating between the null hypothesis (that which we are trying to nullify) and the "nill" hypothesis (there is no difference), reversing the role of the null and alternate hypotheses, and defining an interval within which groups are said to be equivalent. We then work through an example and show how to calculate sample sizes for noninferiority studies.

  19. Almost-Quantum Correlations Violate the No-Restriction Hypothesis.

    Science.gov (United States)

    Sainz, Ana Belén; Guryanova, Yelena; Acín, Antonio; Navascués, Miguel

    2018-05-18

    To identify which principles characterize quantum correlations, it is essential to understand in which sense this set of correlations differs from that of almost-quantum correlations. We solve this problem by invoking the so-called no-restriction hypothesis, an explicit and natural axiom in many reconstructions of quantum theory stating that the set of possible measurements is the dual of the set of states. We prove that, contrary to quantum correlations, no generalized probabilistic theory satisfying the no-restriction hypothesis is able to reproduce the set of almost-quantum correlations. Therefore, any theory whose correlations are exactly, or very close to, the almost-quantum correlations necessarily requires a rule limiting the possible measurements. Our results suggest that the no-restriction hypothesis may play a fundamental role in singling out the set of quantum correlations among other nonsignaling ones.

  20. Motor synergies and the equilibrium-point hypothesis.

    Science.gov (United States)

    Latash, Mark L

    2010-07-01

    The article offers a way to unite three recent developments in the field of motor control and coordination: (1) The notion of synergies is introduced based on the principle of motor abundance; (2) The uncontrolled manifold hypothesis is described as offering a computational framework to identify and quantify synergies; and (3) The equilibrium-point hypothesis is described for a single muscle, single joint, and multijoint systems. Merging these concepts into a single coherent scheme requires focusing on control variables rather than performance variables. The principle of minimal final action is formulated as the guiding principle within the referent configuration hypothesis. Motor actions are associated with setting two types of variables by a controller, those that ultimately define average performance patterns and those that define associated synergies. Predictions of the suggested scheme are reviewed, such as the phenomenon of anticipatory synergy adjustments, quick actions without changes in synergies, atypical synergies, and changes in synergies with practice. A few models are briefly reviewed.

  1. On Using Taylor's Hypothesis for Three-Dimensional Mixing Layers

    Science.gov (United States)

    LeBoeuf, Richard L.; Mehta, Rabindra D.

    1995-01-01

    In the present study, errors in using Taylor's hypothesis to transform measurements obtained in a temporal (or phase) frame onto a spatial one were evaluated. For the first time, phase-averaged ('real') spanwise and streamwise vorticity data measured on a three-dimensional grid were compared directly to those obtained using Taylor's hypothesis. The results show that even the qualitative features of the spanwise and streamwise vorticity distributions given by the two techniques can be very different. This is particularly true in the region of the spanwise roller pairing. The phase-averaged spanwise and streamwise peak vorticity levels given by Taylor's hypothesis are typically lower (by up to 40%) compared to the real measurements.

  2. Epidemiology

    International Nuclear Information System (INIS)

    Hubert, D.

    2009-01-01

    Because of the concern of people, a study of mortality has previously been conducted in two Pennsylvania counties located near manufacturing and reprocessing plants of nuclear materials over the period 1950-1995. No excessive mortality has been identified in the population exposed counties in comparison to control counties. The current study is the continuation of the previous study of mortality over a period of eight additional years (up to 2004) and the addition of a study of cancer incidence over the period 1990-2004 and mortality for causes out of cancer from 1996 to 2004. Method: The population of each county of the study was compared to the population of three control counties selected according to socioeconomic and demographic characteristics, the same way as in the previous study. The demographic, mortality and incidence data for the different counties have been earned at the state of Pennsylvania. Results: over the period 1996-2004, mortality from cancer (10 457 deaths) in the two counties studied was comparable to that of six control counties (relative risk .97 [95% CI .94 -. 99]) and previous results. Similarly, the incidence of cancer was similar in the counties studied (39350 cases of cancer) and the control counties (relative risk .99 [95% CI .97-1.00]). The number of deaths unrelated to cancer was 36 565, very close to the expected number (relative risk .99 [95% CI 1.01-1.01]). Conclusion: Overall, no increase in cancer or non-cancer disease could be attributed to living in counties that had manufacturing and reprocessing plants of nuclear materials. (N.C.)

  3. The frequentist implications of optional stopping on Bayesian hypothesis tests.

    Science.gov (United States)

    Sanborn, Adam N; Hills, Thomas T

    2014-04-01

    Null hypothesis significance testing (NHST) is the most commonly used statistical methodology in psychology. The probability of achieving a value as extreme or more extreme than the statistic obtained from the data is evaluated, and if it is low enough, the null hypothesis is rejected. However, because common experimental practice often clashes with the assumptions underlying NHST, these calculated probabilities are often incorrect. Most commonly, experimenters use tests that assume that sample sizes are fixed in advance of data collection but then use the data to determine when to stop; in the limit, experimenters can use data monitoring to guarantee that the null hypothesis will be rejected. Bayesian hypothesis testing (BHT) provides a solution to these ills because the stopping rule used is irrelevant to the calculation of a Bayes factor. In addition, there are strong mathematical guarantees on the frequentist properties of BHT that are comforting for researchers concerned that stopping rules could influence the Bayes factors produced. Here, we show that these guaranteed bounds have limited scope and often do not apply in psychological research. Specifically, we quantitatively demonstrate the impact of optional stopping on the resulting Bayes factors in two common situations: (1) when the truth is a combination of the hypotheses, such as in a heterogeneous population, and (2) when a hypothesis is composite-taking multiple parameter values-such as the alternative hypothesis in a t-test. We found that, for these situations, while the Bayesian interpretation remains correct regardless of the stopping rule used, the choice of stopping rule can, in some situations, greatly increase the chance of experimenters finding evidence in the direction they desire. We suggest ways to control these frequentist implications of stopping rules on BHT.

  4. Thermalization without eigenstate thermalization hypothesis after a quantum quench.

    Science.gov (United States)

    Mori, Takashi; Shiraishi, Naoto

    2017-08-01

    Nonequilibrium dynamics of a nonintegrable system without the eigenstate thermalization hypothesis is studied. It is shown that, in the thermodynamic limit, this model thermalizes after an arbitrary quantum quench at finite temperature, although it does not satisfy the eigenstate thermalization hypothesis. In contrast, when the system size is finite and the temperature is low enough, the system may not thermalize. In this case, the steady state is well described by the generalized Gibbs ensemble constructed by using highly nonlocal conserved quantities. We also show that this model exhibits prethermalization, in which the prethermalized state is characterized by nonthermal energy eigenstates.

  5. Tunguska, 1908: the gas pouch and soil fluidization hypothesis

    Science.gov (United States)

    Nistor, I.

    2012-01-01

    The Siberian taiga explosion of 30 June 1908 remains one of the great mysteries of the 20th century: millions of trees put down over an area of 2200 km2 without trace of a crater or meteorite fragments. Hundred years of failed searches have followed, resulting in as many flawed hypothesis which could not offer satisfactory explanations: meteorite, comet, UFO, etc. In the author's opinion, the cause is that the energy the explorers looked for was simply not there! The author's hypothesis is that a meteoroid encountered a gas pouch in the atmosphere, producing a devastating explosion, its effects being amplified by soil fluidization.

  6. The equilibrium-point hypothesis--past, present and future.

    Science.gov (United States)

    Feldman, Anatol G; Levin, Mindy F

    2009-01-01

    This chapter is a brief account of fundamentals of the equilibrium-point hypothesis or more adequately called the threshold control theory (TCT). It also compares the TCT with other approaches to motor control. The basic notions of the TCT are reviewed with a major focus on solutions to the problems of multi-muscle and multi-degrees of freedom redundancy. The TCT incorporates cognitive aspects by explaining how neurons recognize that internal (neural) and external (environmental) events match each other. These aspects as well as how motor learning occurs are subjects of further development of the TCT hypothesis.

  7. The cosmic censorship hypothesis and the positive energy conjecture

    International Nuclear Information System (INIS)

    Jang, P.S.; Wald, R.W.

    1979-01-01

    The position so far is summarized. Penrose derived an inequality; if a data set was found to violate this then the assumptions deriving the inequality must be false. In this case it could show a counter example to the cosmic censorship hypothesis. The authors have shown elsewhere that a positive energy argument of Geroch can be modified to rule out a violation of Penrose's inequality with any time-symmetric initial data set whose apparent horizon consists of a single component. This increases confidence in the hypothesis and also indicates there may be a close relationship between this conjecture and the positive energy conjecture. (UK)

  8. Epidemiology, molecular epidemiology, and risk factors for renal cell carcinoma

    Directory of Open Access Journals (Sweden)

    Chiara Paglino

    2011-12-01

    Full Text Available Despite only accounting for approximately 2% of all new primary cancer cases, renal cell carcinoma (RCC incidence has dramatically increased over time. Incidence rates vary greatly according to geographic areas, so that it is extremely likely that exogenous risk factors could play an important role in the development of this cancer. Several risk factors have been linked with RCC, including cigarette smoking, obesity, hypertension (and antihypertensive drugs, chronic kidney diseases (also dialysis and transplantation, as well as the use of certain analgesics. Furthermore, although RCC has not generally been considered an occupational cancer, several types of occupationally-derived exposures have been implicated in its pathogenesis. These include exposure to asbestos, chlorinated solvents, gasoline, diesel exhaust fumes, polycyclic aromatic hydrocarbons, printing inks and dyes, cadmium and lead. Finally, families with a predisposition to the development of renal neoplasms were identified and the genes involved discovered and characterized. Therefore, there are now four well-characterized, genetically determined syndromes associated with an increased incidence of kidney tumors, i.e., Von Hippel Lindau (VHL, Hereditary Papillary Renal Carcinoma (HPRC, Birt-Hogg-Dubé Syndrome (BHD, and Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC. This review will address present knowledge about the epidemiology, molecular epidemiology and risk factors of RCC.

  9. Statistical significance of epidemiological data. Seminar: Evaluation of epidemiological studies

    International Nuclear Information System (INIS)

    Weber, K.H.

    1993-01-01

    In stochastic damages, the numbers of events, e.g. the persons who are affected by or have died of cancer, and thus the relative frequencies (incidence or mortality) are binomially distributed random variables. Their statistical fluctuations can be characterized by confidence intervals. For epidemiologic questions, especially for the analysis of stochastic damages in the low dose range, the following issues are interesting: - Is a sample (a group of persons) with a definite observed damage frequency part of the whole population? - Is an observed frequency difference between two groups of persons random or statistically significant? - Is an observed increase or decrease of the frequencies with increasing dose random or statistically significant and how large is the regression coefficient (= risk coefficient) in this case? These problems can be solved by sttistical tests. So-called distribution-free tests and tests which are not bound to the supposition of normal distribution are of particular interest, such as: - χ 2 -independence test (test in contingency tables); - Fisher-Yates-test; - trend test according to Cochran; - rank correlation test given by Spearman. These tests are explained in terms of selected epidemiologic data, e.g. of leukaemia clusters, of the cancer mortality of the Japanese A-bomb survivors especially in the low dose range as well as on the sample of the cancer mortality in the high background area in Yangjiang (China). (orig.) [de

  10. Molecular Epidemiology of Heart Failure

    Directory of Open Access Journals (Sweden)

    J. Gustav Smith, MD, PhD

    2017-12-01

    Full Text Available Heart failure (HF is the end-stage of all heart disease and arguably constitutes the greatest unmet therapeutic need in cardiovascular medicine today. Classic epidemiological studies have established clinical risk factors for HF, but the cause remains poorly understood in many cases. Biochemical analyses of small case-control series and animal models have described a plethora of molecular characteristics of HF, but a single unifying pathogenic theory is lacking. Heart failure appears to result not only from cardiac overload or injury but also from a complex interplay among genetic, neurohormonal, metabolic, inflammatory, and other biochemical factors acting on the heart. Recent development of robust, high-throughput tools in molecular biology provides opportunity for deep molecular characterization of population-representative cohorts and HF cases (molecular epidemiology, including genome sequencing, profiling of myocardial gene expression and chromatin modifications, plasma composition of proteins and metabolites, and microbiomes. The integration of such detailed information holds promise for improving understanding of HF pathophysiology in humans, identification of therapeutic targets, and definition of disease subgroups beyond the current classification based on ejection fraction which may benefit from improved individual tailoring of therapy. Challenges include: 1 the need for large cohorts with deep, uniform phenotyping; 2 access to the relevant tissues, ideally with repeated sampling to capture dynamic processes; and 3 analytical issues related to integration and analysis of complex datasets. International research consortia have formed to address these challenges and combine datasets, and cohorts with up to 1 million participants are being collected. This paper describes the molecular epidemiology of HF and provides an overview of methods and tissue types and examples of published and ongoing efforts to systematically evaluate molecular

  11. Food insecurity as a driver of obesity in humans: The insurance hypothesis

    Science.gov (United States)

    Nettle, Daniel; Andrews, Clare; Bateson, Melissa

    2016-01-01

    Short abstract Common sense says that obesity is the consequence of too much food. Adaptive reasoning says something rather different: individuals should store fat when access to food is insecure, to buffer themselves against future shortfall. Applied to humans, this principle suggests that food insecurity should be a risk factor for overweight and obesity. We provide a meta-analysis of the extensive epidemiological literature, finding that food insecurity robustly predicts high body weight, but only amongst women in high-income countries. We discuss the relevance of food insecurity to understanding the global obesity problem. Long abstract Integrative explanations of why obesity is more prevalent in some sectors of the human population than others are lacking. Here, we outline and evaluate one candidate explanation, the insurance hypothesis (IH). The IH is rooted in adaptive evolutionary thinking: the function of storing fat is to provide a buffer against shortfall in the food supply. Thus, individuals should store more fat when they receive cues that access to food is uncertain. Applied to humans, this implies that an important proximate driver of obesity should be food insecurity rather than food abundance per se. We integrate several distinct lines of theory and evidence that bear on this hypothesis. We present a theoretical model that shows it is optimal to store more fat when food access is uncertain, and we review the experimental literature from non-human animals showing that fat reserves increase when access to food is restricted. We provide a meta-analysis of 125 epidemiological studies of the association between perceived food insecurity and high body weight in humans. There is a robust positive association, but it is restricted to adult women in high-income countries. We explore why this could be in light of the IH and our theoretical model. We conclude that whilst the IH alone cannot explain the distribution of obesity in the human population, it may

  12. Where is Nepal in the nutrition transition?

    Science.gov (United States)

    Subedi, Yagya Prasad; Marais, Debbi; Newlands, David

    2017-03-01

    Nutrition transition is rapid in developing countries, but Nepalese transition is relatively unknown. This study aimed to describe nutrition transition in Nepal over the past 40 years by identifying the shifts in the Nepalese diets and nutritional status and the underlying shifts associated with this. Popkin's framework was used to identify shifts in Nepalese diet and the inter-relationship of diet with epidemiological, demographic and economic shifts. The current study used quantitative methodology including secondary data analysis based on food balance sheets, economic surveys and the government databases. The Nepalese diet is shifting away from agricultural staple based foods to modern processed foods with higher total energy, total fat, and sugar. The prevalence of overweight/obesity and diet related non-communicable diseases are increasing. Urbanisation is rapid and nutrition transition already advanced in urban area. The Nepalese economic structure has also changed shifting away from agricultural food supply system towards modern processing based food supply system. These changes in the Nepalese diet are triggered by income and urbanisation. The trade liberalisation has made processed foods, edible oil and sugar easily available at supermarkets and fast food outlets. It is clear that Nepal has now entered into the fourth stage of nutrition transition according to Popkin's framework. As a result, overweight, obesity and the prevalence of many noncommunicable diseases are all rapidly growing. A further study is recommended to identify whether urban versus rural, rich versus poor and educated versus uneducated families are experiencing the transition in similar way.

  13. Some aspects of cancer epidemiology

    International Nuclear Information System (INIS)

    Lilienfeld, A.M.

    1982-01-01

    Epidemiolgic studies have strongly suggested that a vast majority (80-90%) of cancers are caused by radiation, chemical and biologic agents; the remainder result from endogenous or genetic factors. Biologically, cancer is most probably the end result of a complex multistage process and therefore may be due to a sequence of exposures to different agents at each of these stages. This emphasizes the need to stress the study of interactions in epidemiologic studies to a greater extent than has been done thus far. Examples of the importance of interactions in several types of cancer are presented

  14. An introduction to mathematical epidemiology

    CERN Document Server

    Martcheva, Maia

    2015-01-01

    The book is a comprehensive, self-contained introduction to the mathematical modeling and analysis of infectious diseases. It includes model building, fitting to data, local and global analysis techniques. Various types of deterministic dynamical models are considered: ordinary differential equation models, delay-differential equation models, difference equation models, age-structured PDE models and diffusion models. It includes various techniques for the computation of the basic reproduction number as well as approaches to the epidemiological interpretation of the reproduction number. MATLAB code is included to facilitate the data fitting and the simulation with age-structured models.

  15. Intrathoracic neoplasia: Epidemiology and etiology

    Energy Technology Data Exchange (ETDEWEB)

    Weller, R.E.

    1992-05-01

    Neoplasms of the thorax encompass those derived from the thoracic wall, trachea, mediastinum, lungs and pleura. They represent a wide variety of lesions including benign and malignant tumors arising from many tissues. The large surface area, 60 to 90 m{sup 2} in man, represented by the respiratory epithelium and associated thoracic structures are ideal targets for carcinogens carried by inspired air. The topic of discussion in this report is the epidemiology, etiology, and mechanisms of spontaneous intrathoracic neoplasia in animals and man. Much of what we know or suspect about thoracic neoplasia in animals has been extrapolated from experimentally-induced neoplasms.

  16. Epidemiology: past, present and future.

    Science.gov (United States)

    Kesteloot, H

    2004-01-01

    Epidemiology in the past was concerned essentially by the study of infectious diseases which were the cause of huge mortalities especially since urbanisation was initiated. Epidemics of pest, typhus, cholera, influenza a.o. were common. The epidemics were halted by better hygiene, vaccination and antibiotics. Since the second world war epidemiology was dominated by an "epidemic" of new chronic diseases, especially heart disease and cancer. This was due to an increase in life span and to an increase in smoking habits and in the intake of saturated fat and a too small intake of fruit and vegetables combined with a too high intake of salt (NaCl). Gradually epidemiology evolved as the study of the causes, the distribution, the risk factors and the prevention of chronic diseases, but also including accidents, suicide, depression a.o., diseases with a mass occurrence at the population level. The importance of nutrition as a determinant of health gradually became recognized, but remains undervalued by the medical profession. Mortality at the population level follows some simple mathematical laws and can be represented accurately (r2>0.99) between the ages of 35 and 84 year by either Gompertz equations (ln mortality versus age) or by a polynomial equation (ln mortality versus age, age2). This is valid for all populations and both sexes and remains valid at times of great and rapid changes in mortality. This shows that measures for prevention should be directed towards the total population. The future of epidemiology should be directed towards the slowing of the ageing process at the population level by a healthy life style consisting of: not smoking, avoiding obesity, a fair amount of physical activity and a healthy nutrition i.e little salt, little saturated fat, an adequate amount of omega-3 fatty acids and a large amount of fruit and vegetables, with an occasional glass of red wine. This contains the secret of a long and healthy life. Conceptually it will be important

  17. Epidemiologic studies of radioactively contaminated environments and cancer clusters

    International Nuclear Information System (INIS)

    Boice, J.D. Jr.

    1991-01-01

    This paper reports on epidemiologic studies which address the distribution and determinants of disease in human populations. Investigations of the possible adverse effects of living in radioactively contaminated environments are difficult to conduct, however, because human populations tend to be fairly mobile, cumulative exposures to individuals from environmental conditions are difficult to estimate, and the risks associated with such exposures tend to be small relative to background levels of disease. Such studies can be arbitrarily classified as geographic correlation surveys, analytic studies, and cluster evaluations. Geographic correlation studies (ecological surveys) relate disease in populations to area characteristics. Although exposure to individuals is unknown, these exploratory or hypothesis-generating studies can identify areas to target for further in-depth evaluation. Analytic investigations relate individual exposure information to disease occurrence. Unusual occurrences of disease in time and place (clusters) occasionally point to a common environmental factor; cluster evaluations have been most successful in identifying the source of infectious disease outbreaks

  18. Mental models accurately predict emotion transitions.

    Science.gov (United States)

    Thornton, Mark A; Tamir, Diana I

    2017-06-06

    Successful social interactions depend on people's ability to predict others' future actions and emotions. People possess many mechanisms for perceiving others' current emotional states, but how might they use this information to predict others' future states? We hypothesized that people might capitalize on an overlooked aspect of affective experience: current emotions predict future emotions. By attending to regularities in emotion transitions, perceivers might develop accurate mental models of others' emotional dynamics. People could then use these mental models of emotion transitions to predict others' future emotions from currently observable emotions. To test this hypothesis, studies 1-3 used data from three extant experience-sampling datasets to establish the actual rates of emotional transitions. We then collected three parallel datasets in which participants rated the transition likelihoods between the same set of emotions. Participants' ratings of emotion transitions predicted others' experienced transitional likelihoods with high accuracy. Study 4 demonstrated that four conceptual dimensions of mental state representation-valence, social impact, rationality, and human mind-inform participants' mental models. Study 5 used 2 million emotion reports on the Experience Project to replicate both of these findings: again people reported accurate models of emotion transitions, and these models were informed by the same four conceptual dimensions. Importantly, neither these conceptual dimensions nor holistic similarity could fully explain participants' accuracy, suggesting that their mental models contain accurate information about emotion dynamics above and beyond what might be predicted by static emotion knowledge alone.

  19. Mental models accurately predict emotion transitions

    Science.gov (United States)

    Thornton, Mark A.; Tamir, Diana I.

    2017-01-01

    Successful social interactions depend on people’s ability to predict others’ future actions and emotions. People possess many mechanisms for perceiving others’ current emotional states, but how might they use this information to predict others’ future states? We hypothesized that people might capitalize on an overlooked aspect of affective experience: current emotions predict future emotions. By attending to regularities in emotion transitions, perceivers might develop accurate mental models of others’ emotional dynamics. People could then use these mental models of emotion transitions to predict others’ future emotions from currently observable emotions. To test this hypothesis, studies 1–3 used data from three extant experience-sampling datasets to establish the actual rates of emotional transitions. We then collected three parallel datasets in which participants rated the transition likelihoods between the same set of emotions. Participants’ ratings of emotion transitions predicted others’ experienced transitional likelihoods with high accuracy. Study 4 demonstrated that four conceptual dimensions of mental state representation—valence, social impact, rationality, and human mind—inform participants’ mental models. Study 5 used 2 million emotion reports on the Experience Project to replicate both of these findings: again people reported accurate models of emotion transitions, and these models were informed by the same four conceptual dimensions. Importantly, neither these conceptual dimensions nor holistic similarity could fully explain participants’ accuracy, suggesting that their mental models contain accurate information about emotion dynamics above and beyond what might be predicted by static emotion knowledge alone. PMID:28533373

  20. Hypothesis: Cryptosporidium genetic diversity mirrors national disease notification rate

    OpenAIRE

    Takumi, Katsuhisa; Cacci?, Simone M.; van der Giessen, Joke; Xiao, Lihua; Sprong, Hein

    2015-01-01

    Background Cryptosporidiosis is a gastrointestinal disease affecting many people worldwide. Disease incidence is often unknown and surveillance of human cryptosporidiosis is installed in only a handful of developed countries. A genetic marker that mirrors disease incidence is potentially a powerful tool for monitoring the two primary human infected species of Cryptosporidium. Methods We used the molecular epidemiological database with Cryptosporidium isolates from ZoopNet, which currently con...

  1. [Popper and the problem of induction in epidemiology].

    Science.gov (United States)

    Banegas, J R; Rodríguez Artalejo, F; del Rey Calero, J

    2000-01-01

    In this article we are discussing a few of the contributions by the Austro-British philosopher Karl R. Popper, one of our most influential contemporary thinkers, whose epistemological and socio-political theories have also penetrated the sphere of epidemiology. We are focusing mainly on the so-called problem of induction. We sustain, in line with Popper, that the scientific method does not use inductive reasoning, but rather hypothetical-deductive reasoning. Although the movement from the data evaluating a hypothesis to a conclusion on the latter goes from the specific to the general, that is, in an inductive direction, the induction does not exist as a reasoning process or inference. That is, there is no method that enables us to infer or to verify hypotheses or theories (we cannot explore all of the possible situations to see whether the theory stands up), or even to render them very probable. Besides, scientists look for highly informative theories, not highly probable ones. What we actually do is to propose a hypothesis as a tentative solution to a problem, to confront the prediction deduced from the hypothesis with actual experience, and evaluate whether the hypothesis is rejected or not by the facts. As theories cannot be verified, we can only accept them if they withstand an attempt to reject them. Consequently, the test of a theory consists of criticism or a serious attempt at falsification, that is, the elimination of error within a theory, in order to reject it if it is false. The objective is, thus, the search for true theories. For this purpose, the scientific method uses a systematic set of methodological (not logical) rules, that is, decisions. These methodological rules or principles can be summed up in two: [symbol: see text]be inventive and critical!, that is, propose bold hypotheses and subject them to severe tests of experience. Logic plays its role mainly by allowing us to deduce from a hypothesis the predictions to be confronted with the facts

  2. New Hypothesis and Theory about Functions of Sleep and Dreams

    Directory of Open Access Journals (Sweden)

    Nikola N. Ilanković

    2014-03-01

    Conclusion: IEP-P1 could be a new biological marker to distinction of sleep organization in different psychotic states and other states of altered consciousness. The developed statistical models could be the basis for new hypothesis and theories about functions of sleep and dreams.

  3. A test of the reward-value hypothesis.

    Science.gov (United States)

    Smith, Alexandra E; Dalecki, Stefan J; Crystal, Jonathon D

    2017-03-01

    Rats retain source memory (memory for the origin of information) over a retention interval of at least 1 week, whereas their spatial working memory (radial maze locations) decays within approximately 1 day. We have argued that different forgetting functions dissociate memory systems. However, the two tasks, in our previous work, used different reward values. The source memory task used multiple pellets of a preferred food flavor (chocolate), whereas the spatial working memory task provided access to a single pellet of standard chow-flavored food at each location. Thus, according to the reward-value hypothesis, enhanced performance in the source memory task stems from enhanced encoding/memory of a preferred reward. We tested the reward-value hypothesis by using a standard 8-arm radial maze task to compare spatial working memory accuracy of rats rewarded with either multiple chocolate or chow pellets at each location using a between-subjects design. The reward-value hypothesis predicts superior accuracy for high-valued rewards. We documented equivalent spatial memory accuracy for high- and low-value rewards. Importantly, a 24-h retention interval produced equivalent spatial working memory accuracy for both flavors. These data are inconsistent with the reward-value hypothesis and suggest that reward value does not explain our earlier findings that source memory survives unusually long retention intervals.

  4. Revisiting Hudson’s (1992) OO = O2 hypothesis

    DEFF Research Database (Denmark)

    Shibuya, Yoshikata; Jensen, Kim Ebensgaard

    2018-01-01

    In an important paper on the English “double-object”, or ditransitive, construction, Richard Hudson proposes a hypothesis that conflates the ditransitive direct object, or O2, and the monotransitive direct object, or OO, into the same syntactic functional category. While making important departures...

  5. Hypothesis, Prediction, and Conclusion: Using Nature of Science Terminology Correctly

    Science.gov (United States)

    Eastwell, Peter

    2012-01-01

    This paper defines the terms "hypothesis," "prediction," and "conclusion" and shows how to use the terms correctly in scientific investigations in both the school and science education research contexts. The scientific method, or hypothetico-deductive (HD) approach, is described and it is argued that an understanding of the scientific method,…

  6. A sequential hypothesis test based on a generalized Azuma inequality

    NARCIS (Netherlands)

    Reijsbergen, D.P.; Scheinhardt, Willem R.W.; de Boer, Pieter-Tjerk

    We present a new power-one sequential hypothesis test based on a bound for the probability that a bounded zero-mean martingale ever crosses a curve of the form $a(n+k)^b$. The proof of the bound is of independent interest.

  7. Planned Hypothesis Tests Are Not Necessarily Exempt from Multiplicity Adjustment

    Science.gov (United States)

    Frane, Andrew V.

    2015-01-01

    Scientific research often involves testing more than one hypothesis at a time, which can inflate the probability that a Type I error (false discovery) will occur. To prevent this Type I error inflation, adjustments can be made to the testing procedure that compensate for the number of tests. Yet many researchers believe that such adjustments are…

  8. A default Bayesian hypothesis test for correlations and partial correlations

    NARCIS (Netherlands)

    Wetzels, R.; Wagenmakers, E.J.

    2012-01-01

    We propose a default Bayesian hypothesis test for the presence of a correlation or a partial correlation. The test is a direct application of Bayesian techniques for variable selection in regression models. The test is easy to apply and yields practical advantages that the standard frequentist tests

  9. Semiparametric Power Envelopes for Tests of the Unit Root Hypothesis

    DEFF Research Database (Denmark)

    Jansson, Michael

    This paper derives asymptotic power envelopes for tests of the unit root hypothesis in a zero-mean AR(1) model. The power envelopes are derived using the limits of experiments approach and are semiparametric in the sense that the underlying error distribution is treated as an unknown...

  10. Using Employer Hiring Behavior to Test the Educational Signaling Hypothesis

    NARCIS (Netherlands)

    Albrecht, J.W.; van Ours, J.C.

    2001-01-01

    This paper presents a test of the educational signaling hypothesis.If employers use education as a signal in the hiring process, they will rely more on education when less is otherwise known about applicants.We nd that employers are more likely to lower educational standards when an informal, more

  11. Explorations in Statistics: Hypothesis Tests and P Values

    Science.gov (United States)

    Curran-Everett, Douglas

    2009-01-01

    Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This second installment of "Explorations in Statistics" delves into test statistics and P values, two concepts fundamental to the test of a scientific null hypothesis. The essence of a test statistic is that it compares what…

  12. THE BARKER HYPOTHESIS: IMPLICATIONS FOR FUTURE DIRECTIONS IN TOXICOLOGY RESEARCH

    Science.gov (United States)

    This review covers the past year’s papers germane to the Barker hypothesis. While much of the literature has centered on maternal and developmental nutrition, new findings have emerged on the ability of toxic exposures during development to impact fetal/developmental programming....

  13. Tax Evasion, Information Reporting, and the Regressive Bias Hypothesis

    DEFF Research Database (Denmark)

    Boserup, Simon Halphen; Pinje, Jori Veng

    A robust prediction from the tax evasion literature is that optimal auditing induces a regressive bias in effective tax rates compared to statutory rates. If correct, this will have important distributional consequences. Nevertheless, the regressive bias hypothesis has never been tested empirically...

  14. Developmental Dyslexia: The Visual Attention Span Deficit Hypothesis

    Science.gov (United States)

    Bosse, Marie-Line; Tainturier, Marie Josephe; Valdois, Sylviane

    2007-01-01

    The visual attention (VA) span is defined as the amount of distinct visual elements which can be processed in parallel in a multi-element array. Both recent empirical data and theoretical accounts suggest that a VA span deficit might contribute to developmental dyslexia, independently of a phonological disorder. In this study, this hypothesis was…

  15. The "Discouraged-Business-Major" Hypothesis: Policy Implications

    Science.gov (United States)

    Marangos, John

    2012-01-01

    This paper uses a relatively large dataset of the stated academic major preferences of economics majors at a relatively large, not highly selective, public university in the USA to identify the "discouraged-business-majors" (DBMs). The DBM hypothesis addresses the phenomenon where students who are screened out of the business curriculum often…

  16. The Twin Deficits Hypothesis: An Empirical Analysis for Tanzania

    Directory of Open Access Journals (Sweden)

    Manamba Epaphra

    2017-09-01

    Full Text Available This paper examines the relationship between current account and government budget deficits in Tanzania. The paper tests the validity of the twin deficits hypothesis, using annual time series data for the 1966-2015 period. The paper is thought to be significant because the concept of the twin deficit hypothesis is fraught with controversy. Some researches support the hypothesis that there is a positive relationship between current account deficits and fiscal deficits in the economy while others do not. In this paper, the empirical tests fail to reject the twin deficits hypothesis, indicating that rising budget deficits put more strain on the current account deficits in Tanzania. Specifically, the Vector Error Correction Model results support the conventional theory of a positive relationship between fiscal and external balances, with a relatively high speed of adjustment toward the equilibrium position. This evidence is consistent with a small open economy. To address the problem that may result from this kind of relationship, appropriate policy variables for reducing budget deficits such as reduction in non-development expenditure, enhancement of domestic revenue collection and actively fight corruption and tax evasion should be adopted. The government should also target export oriented firms and encourage an import substitution industry by creating favorable business environments.

  17. Etiology of common childhood acute lymphoblastic leukemia: the adrenal hypothesis

    DEFF Research Database (Denmark)

    Schmiegelow, K.; Vestergaard, T.; Nielsen, S.M.

    2008-01-01

    The pattern of infections in the first years of life modulates our immune system, and a low incidence of infections has been linked to an increased risk of common childhood acute lymphoblastic leukemia (ALL). We here present a new interpretation of these observations--the adrenal hypothesis...

  18. Cross-system log file analysis for hypothesis testing

    NARCIS (Netherlands)

    Glahn, Christian; Specht, Marcus; Schoonenboom, Judith; Sligte, Henk; Moghnieh, Ayman; Hernández-Leo, Davinia; Stefanov, Krassen; Lemmers, Ruud; Koper, Rob

    2008-01-01

    Glahn, C., Specht, M., Schoonenboom, J., Sligte, H., Moghnieh, A., Hernández-Leo, D. Stefanov, K., Lemmers, R., & Koper, R. (2008). Cross-system log file analysis for hypothesis testing. In H. Sligte & R. Koper (Eds.), Proceedings of the 4th TENCompetence Open Workshop. Empowering Learners for

  19. The catecholaminergic-cholinergic balance hypothesis of bipolar disorder revisited

    Science.gov (United States)

    van Enkhuizen, Jordy; Janowsky, David S; Olivier, Berend; Minassian, Arpi; Perry, William; Young, Jared W; Geyer, Mark A

    2014-01-01

    Bipolar disorder is a unique illness characterized by fluctuations between mood states of depression and mania. Originally, an adrenergic-cholinergic balance hypothesis was postulated to underlie these different affective states. In this review, we update this hypothesis with recent findings from human and animal studies, suggesting that a catecholaminergic-cholinergic hypothesis may be more relevant. Evidence from neuroimaging studies, neuropharmacological interventions, and genetic associations support the notion that increased cholinergic functioning underlies depression, whereas increased activations of the catecholamines (dopamine and norepinephrine) underlie mania. Elevated functional acetylcholine during depression may affect both muscarinic and nicotinic acetylcholine receptors in a compensatory fashion. Increased functional dopamine and norepinephrine during mania on the other hand may affect receptor expression and functioning of dopamine reuptake transporters. Despite increasing evidence supporting this hypothesis, a relationship between these two neurotransmitter systems that could explain cycling between states of depression and mania is missing. Future studies should focus on the influence of environmental stimuli and genetic susceptibilities that may affect the catecholaminergic-cholinergic balance underlying cycling between the affective states. Overall, observations from recent studies add important data to this revised balance theory of bipolar disorder, renewing interest in this field of research. PMID:25107282

  20. A "Projective" Test of the Golden Section Hypothesis.

    Science.gov (United States)

    Lee, Chris; Adams-Webber, Jack

    1987-01-01

    In a projective test of the golden section hypothesis, 24 high school students rated themselves and 10 comic strip characters on basis of 12 bipolar constructs. Overall proportion of cartoon figures which subjects assigned to positive poles of constructs was very close to golden section. (Author/NB)

  1. The Lehman Sisters Hypothesis: an exploration of literature and bankers

    NARCIS (Netherlands)

    I.P. van Staveren (Irene)

    2012-01-01

    textabstractAbstract This article tests the Lehman Sisters Hypothesis in two complementary, although incomplete ways. It reviews the diverse empirical literature in behavioral, experimental, and neuroeconomics as well as related fields of behavioral research. And it presents the findings from an

  2. The Lehman Sisters Hypothesis: an exploration of literature and bankers

    NARCIS (Netherlands)

    I.P. van Staveren (Irene)

    2012-01-01

    textabstractThis article tests the Lehman Sisters Hypothesis in two complementary, although incomplete ways. It reviews the diverse empirical literature in behavioural, experimental, and neuroeconomics as well as related fields of behavioural research. And it presents the findings from an

  3. A Life-Course Perspective on the "Gateway Hypothesis"

    Science.gov (United States)

    Van Gundy, Karen; Rebellon, Cesar J.

    2010-01-01

    Drawing on stress and life-course perspectives and using panel data from 1,286 south Florida young adults, we assess three critical questions regarding the role of marijuana in the "gateway hypothesis." First, does teen marijuana use independently (causally) affect subsequent use of more dangerous substances? Second, if so, does that…

  4. Shaping Up the Practice of Null Hypothesis Significance Testing.

    Science.gov (United States)

    Wainer, Howard; Robinson, Daniel H.

    2003-01-01

    Discusses criticisms of null hypothesis significance testing (NHST), suggesting that historical use of NHST was reasonable, and current users should read Sir Ronald Fisher's applied work. Notes that modifications to NHST and interpretations of its outcomes might better suit the needs of modern science. Concludes that NHST is most often useful as…

  5. Rational Variability in Children's Causal Inferences: The Sampling Hypothesis

    Science.gov (United States)

    Denison, Stephanie; Bonawitz, Elizabeth; Gopnik, Alison; Griffiths, Thomas L.

    2013-01-01

    We present a proposal--"The Sampling Hypothesis"--suggesting that the variability in young children's responses may be part of a rational strategy for inductive inference. In particular, we argue that young learners may be randomly sampling from the set of possible hypotheses that explain the observed data, producing different hypotheses with…

  6. Assessing Threat Detection Scenarios through Hypothesis Generation and Testing

    Science.gov (United States)

    2015-12-01

    Publications. Field, A. (2005). Discovering statistics using SPSS (2nd ed.). Thousand Oaks, CA: Sage Publications. Fisher, S. D., Gettys, C. F...therefore, subsequent F statistics are reported using the Huynh-Feldt correction (Greenhouse-Geisser Epsilon > .775). Experienced and inexperienced...change in hypothesis using experience and initial confidence as predictors. In the Dog Day scenario, the regression was not statistically

  7. Fecundity of trees and the colonization-competition hypothesis

    Science.gov (United States)

    James S. Clark; Shannon LaDeau; Ines Ibanez

    2004-01-01

    Colonization-competition trade-offs represent a stabilizing mechanism that is thought to maintain diversity of forest trees. If so, then early-successional species should benefit from high capacity to colonize new sites, and late-successional species should be good competitors. Tests of this hypothesis in forests have been precluded by an inability to estimate...

  8. Scalar fields and cosmic censorship hypothesis in general relativity

    International Nuclear Information System (INIS)

    Parnovs'kij, S.L.; Gajdamaka, O.Z.

    2004-01-01

    We discuss an influence of the presence of some nonstandard scalar fields in the vicinity of naked time-like singularity on the type and properties of this singularity. The main goal is to study the validity of the Penrose's Cosmic Censorship hypothesis in the General Relativity

  9. Hypothesis Sampling Systems among Preoperational and Concrete Operational Kindergarten Children

    Science.gov (United States)

    Gholson, Barry; And Others

    1976-01-01

    Preoperational and concrete operational kindergarten children received stimulus differentiation training, either with or without feedback, and then a series of discrimination learning problems in which a blank trial probe was used to detect a child's hypothesis after each feedback trial. Piagetian stage theory requires elaboration to account…

  10. Bayesian Approaches to Imputation, Hypothesis Testing, and Parameter Estimation

    Science.gov (United States)

    Ross, Steven J.; Mackey, Beth

    2015-01-01

    This chapter introduces three applications of Bayesian inference to common and novel issues in second language research. After a review of the critiques of conventional hypothesis testing, our focus centers on ways Bayesian inference can be used for dealing with missing data, for testing theory-driven substantive hypotheses without a default null…

  11. Animal Models for Testing the DOHaD Hypothesis

    Science.gov (United States)

    Since the seminal work in human populations by David Barker and colleagues, several species of animals have been used in the laboratory to test the Developmental Origins of Health and Disease (DOHaD) hypothesis. Rats, mice, guinea pigs, sheep, pigs and non-human primates have bee...

  12. An investigation of the competitiveness hypothesis of the resource curse

    NARCIS (Netherlands)

    L.A. Serino (Leandro)

    2008-01-01

    textabstractIn this paper I investigate the competitiveness explanation of the resource curse: to what extent slow growth in primary producer countries is related to the properties of this pattern of trade specialization. To address this hypothesis that has not been adequately explored in the

  13. Fertility and pregnancy: an epidemiologic perspective

    National Research Council Canada - National Science Library

    Wilcox, Allen J

    2010-01-01

    .... Weaving together history, biology, obstetrics, pediatrics, demography, infectious diseases, molecular genetics, and evolutionary biology, Allen Wilcox brings a fresh coherence to the epidemiologic...

  14. Clinical Epidemiology Unit - overview of research areas

    Science.gov (United States)

    Clinical Epidemiology Unit (CEU) conducts etiologic research with potential clinical and public health applications, and leads studies evaluating population-based early detection and cancer prevention strategies

  15. en epidemiología

    Directory of Open Access Journals (Sweden)

    Ana V. Diez Roux

    2008-01-01

    Full Text Available La epidemiología sociocultural se caracteriza por la integración de procesos sociales, culturales, económicos y políticos con procesos biológicos en el estudio de los determinantes de la salud. Por definición, esto implica la consideración de determinantes especificados a múltiples niveles, desde los genes hasta las características de la sociedad en su totalidad. En este artículo se analizan diversos problemas metodológicos que surgen en epidemiología (y en las ciencias sociales en general por la presencia de múltiples niveles de organización que pueden ser relevantes para entender las causas de la salud y la enfermedad. Se subraya la necesidad de investigar conjuntamente (o de integrar determinantes de la salud definidos a distintos niveles. El artículo concluye con un examen de las implicaciones de la presencia de múltiples niveles para el estudio de los determinantes sociales o culturales de la salud.

  16. Epidemiology: second-rate science?

    Science.gov (United States)

    Parascandola, M

    1998-01-01

    In recent years epidemiology has come under increasing criticism in regulatory and public arenas for being "unscientific." The tobacco industry has taken advantage of this, insisting for decades that evidence linking cigarettes and lung cancer falls short of proof. Moreover, many epidemiologists remain unduly skeptical and self-conscious about the status of their own causal claims. This situation persists in part because of a widespread belief that only the laboratory can provide evidence sufficient for scientific proof. Adherents of this view erroneously believe that there is no element of uncertainty or inductive inference in the "direct observation" of the laboratory researcher and that epidemiology provides mere "circumstantial" evidence. The historical roots of this attitude can be traced to philosopher John Stuart Mill and physiologist Claude Bernard and their influence on modern experimental thinking. The author uses the debate over cigarettes and lung cancer to examine ideas of proof in medical science and public health, concluding that inductive inference from a limited sample to a larger population is an element in all empirical science.

  17. Epidemiology of Clostridium difficile Infection

    Science.gov (United States)

    DePestel, Daryl D.; Aronoff, David M.

    2014-01-01

    There has been dramatic change in the epidemiology of Clostridium difficile infection (CDI) since the turn of the 21st Century noted by a marked increase in incidence and severity, occurring at a disproportionately higher frequency in older patients. Historically considered a nosocomial infection associated with antibiotic exposure, CDI has now also emerged in the community in populations previously considered low risk. Emerging risk factors and disease recurrence represent continued challenges in the management of CDI. The increased incidence and severity associated with CDI has coincided with the emergence and rapid spread of a previously rare strain, ribotype 027. Recent data from the U.S. and Europe suggest the incidence of CDI may have reached a crescendo in recent years and is perhaps beginning to plateau. The acute-care direct costs of CDI were estimated to be $4.8 billion in 2008. However, nearly all the published studies have focused on CDI diagnosed and treated in acute-care hospital setting and fail to measure the burden outside the hospital, including recently discharged patients, outpatients, and those in long-term care facilities. Enhanced surveillance methods are needed to monitor the incidence, identify populations at risk, and characterize the molecular epidemiology of strains causing CDI. PMID:24064435

  18. Childhood vitiligo: Clinical epidemiological profile

    Directory of Open Access Journals (Sweden)

    Asmae Lahlou

    2017-07-01

    Full Text Available Objective: To study the clinical and the epidemiologic profiles of childhood vitiligo. Patients and Methods: We prospectively analyzed the clinical data of children with vitiligo presented to the dermatology derpartement at University Hospital – Fès for 5 years from May 2011 to May 2016. This study included 31 patients. All patients were assessed for the natural history, clinical characteristics, family history, and associated abnormalities of vitiligo. Results: Of the 31 children with vitiligo 9 (29,03% were boys and 21 (67.74% were girls. The mean age of onset of the vitiligo was 10 years. The mean duration of the disease was 38,9 weeks. The most common type of vitiligo was vitiligo vulgaris (49.5% followed by focal vitiligo (39%, acrofacial vitiligo (32%, and segmental vitiligo (16% The most frequent site of onset was the extremities followed by the head and the neck, then the trunk and the genitalia. Of the 31 children with vitiligo, 39% had a family history and 4 % had an antecedent of autoimmune diesease like le diabète, une thyroïdite, l’anémie et le psoriasis, retrouvé. Conclusion: Our children have a strong family history of vitiligo and they are developing the disease at a slightly older age compared with those of other studies; however, other epidemiologic features appear to be similar to those reported in the previously published studies.

  19. Epidemiologic research program: Selected bibliography

    International Nuclear Information System (INIS)

    1993-05-01

    This bibliography is a current listing of scientific reports from epidemiologic and related activities sponsored by the Department of Energy. The Office of Epidemiology and Health Surveillance now is the departmental focal point for these activities and any others relating to the study of human health effects. The Office's mission is evolving to encompass the new role of the Department in environmental restoration, weapons dismantlement and nuclear material storage, and development of new energy technologies. Publications in these areas will be included in future editions of the bibliography. The present edition brings the listing up to date, and should facilitate access to specific reports. The program has been divided into several general areas of activity: the Radiation Effects Research Foundation, which supports studies of survivors of the atomic weapons in Hiroshima and Nagasaki; mortality and morbidity studies of DOE workers; studies on internally deposited alpha emitters; medical/histologic studies; studies on the genetic aspects of radiation damage; community health surveillance studies; and the development of computational techniques and of databases to make the results as widely useful as possible

  20. The Effectiveness of the Comprehension Hypothesis: A Review on the Current Research on Incidental Vocabulary Acquisition

    Science.gov (United States)

    Ponniah, Joseph

    2011-01-01

    The Comprehension Hypothesis (CH) is the most powerful hypothesis in the field of Second Language Acquisition despite the presence of the rivals the skill-building hypothesis, the output hypothesis, and the interaction hypothesis. The competing hypotheses state that consciously learned linguistic knowledge is a necessary step for the development…

  1. Simultaneity modeling analysis of the environmental Kuznets curve hypothesis

    International Nuclear Information System (INIS)

    Ben Youssef, Adel; Hammoudeh, Shawkat; Omri, Anis

    2016-01-01

    The environmental Kuznets curve (EKC) hypothesis has been recognized in the environmental economics literature since the 1990's. Various statistical tests have been used on time series, cross section and panel data related to single and groups of countries to validate this hypothesis. In the literature, the validation has always been conducted by using a single equation. However, since both the environment and income variables are endogenous, the estimation of a single equation model when simultaneity exists produces inconsistent and biased estimates. Therefore, we formulate simultaneous two-equation models to investigate the EKC hypothesis for fifty-six countries, using annual panel data from 1990 to 2012, with the end year is determined by data availability for the panel. To make the panel data analysis more homogeneous, we investigate this issue for a three income-based panels (namely, high-, middle-, and low-income panels) given several explanatory variables. Our results indicate that there exists a bidirectional causality between economic growth and pollution emissions in the overall panels. We also find that the relationship is nonlinear and has an inverted U-shape for all the considered panels. Policy implications are provided. - Highlights: • We have given a new look for the validity of the EKC hypothesis. • We formulate two-simultaneous equation models to validate this hypothesis for fifty-six countries. • We find a bidirectional causality between economic growth and pollution emissions. • We also discover an inverted U-shaped between environmental degradation and economic growth. • This relationship varies at different stages of economic development.

  2. A critique of statistical hypothesis testing in clinical research

    Directory of Open Access Journals (Sweden)

    Somik Raha

    2011-01-01

    Full Text Available Many have documented the difficulty of using the current paradigm of Randomized Controlled Trials (RCTs to test and validate the effectiveness of alternative medical systems such as Ayurveda. This paper critiques the applicability of RCTs for all clinical knowledge-seeking endeavors, of which Ayurveda research is a part. This is done by examining statistical hypothesis testing, the underlying foundation of RCTs, from a practical and philosophical perspective. In the philosophical critique, the two main worldviews of probability are that of the Bayesian and the frequentist. The frequentist worldview is a special case of the Bayesian worldview requiring the unrealistic assumptions of knowing nothing about the universe and believing that all observations are unrelated to each other. Many have claimed that the first belief is necessary for science, and this claim is debunked by comparing variations in learning with different prior beliefs. Moving beyond the Bayesian and frequentist worldviews, the notion of hypothesis testing itself is challenged on the grounds that a hypothesis is an unclear distinction, and assigning a probability on an unclear distinction is an exercise that does not lead to clarity of action. This critique is of the theory itself and not any particular application of statistical hypothesis testing. A decision-making frame is proposed as a way of both addressing this critique and transcending ideological debates on probability. An example of a Bayesian decision-making approach is shown as an alternative to statistical hypothesis testing, utilizing data from a past clinical trial that studied the effect of Aspirin on heart attacks in a sample population of doctors. As a big reason for the prevalence of RCTs in academia is legislation requiring it, the ethics of legislating the use of statistical methods for clinical research is also examined.

  3. Mechanisms of eyewitness suggestibility: tests of the explanatory role hypothesis.

    Science.gov (United States)

    Rindal, Eric J; Chrobak, Quin M; Zaragoza, Maria S; Weihing, Caitlin A

    2017-10-01

    In a recent paper, Chrobak and Zaragoza (Journal of Experimental Psychology: General, 142(3), 827-844, 2013) proposed the explanatory role hypothesis, which posits that the likelihood of developing false memories for post-event suggestions is a function of the explanatory function the suggestion serves. In support of this hypothesis, they provided evidence that participant-witnesses were especially likely to develop false memories for their forced fabrications when their fabrications helped to explain outcomes they had witnessed. In three experiments, we test the generality of the explanatory role hypothesis as a mechanism of eyewitness suggestibility by assessing whether this hypothesis can predict suggestibility errors in (a) situations where the post-event suggestions are provided by the experimenter (as opposed to fabricated by the participant), and (b) across a variety of memory measures and measures of recollective experience. In support of the explanatory role hypothesis, participants were more likely to subsequently freely report (E1) and recollect the suggestions as part of the witnessed event (E2, source test) when the post-event suggestion helped to provide a causal explanation for a witnessed outcome than when it did not serve this explanatory role. Participants were also less likely to recollect the suggestions as part of the witnessed event (on measures of subjective experience) when their explanatory strength had been reduced by the presence of an alternative explanation that could explain the same outcome (E3, source test + warning). Collectively, the results provide strong evidence that the search for explanatory coherence influences people's tendency to misremember witnessing events that were only suggested to them.

  4. Physiological constrains on Sverdrup's Critical-Depth-Hypothesis: the influences of dark respiration and sinking

    DEFF Research Database (Denmark)

    Lindemann, Christian; Backhaus, Jan O.; St. John, Michael

    2015-01-01

    of the spring bloom. However, they neglect the cells ability to modify vital rates in response to changes in the external environment. In this study, we use a non-hydrostatic convection model coupled to an Individual-Based-Model to simulate changes phytoplankton cells during the transition from winter...... conditions as driven by convective mixing, and the onset of thermal stratification resulting in the spring bloom. The comparison between a simulation using a standard fixed rate approach in line with the original Sverdrup hypothesis and a simulation parameterized to include variable respiration and sinking...... replicate field observations when employing unrealistic parameter values. These results highlight the necessity to consider not only the physical and biological external controls determining phytoplankton dynamics but also the cells ability to modify critical physiological rates in response to external...

  5. Quantifying the limits of transition state theory in enzymatic catalysis.

    Science.gov (United States)

    Zinovjev, Kirill; Tuñón, Iñaki

    2017-11-21

    While being one of the most popular reaction rate theories, the applicability of transition state theory to the study of enzymatic reactions has been often challenged. The complex dynamic nature of the protein environment raised the question about the validity of the nonrecrossing hypothesis, a cornerstone in this theory. We present a computational strategy to quantify the error associated to transition state theory from the number of recrossings observed at the equicommittor, which is the best possible dividing surface. Application of a direct multidimensional transition state optimization to the hydride transfer step in human dihydrofolate reductase shows that both the participation of the protein degrees of freedom in the reaction coordinate and the error associated to the nonrecrossing hypothesis are small. Thus, the use of transition state theory, even with simplified reaction coordinates, provides a good theoretical framework for the study of enzymatic catalysis. Copyright © 2017 the Author(s). Published by PNAS.

  6. Factors involved in the paradox of reverse epidemiology.

    Science.gov (United States)

    Martín-Ponce, Esther; Santolaria, Francisco; Alemán-Valls, María-Remedios; González-Reimers, Emilio; Martínez-Riera, Antonio; Rodríguez-Gaspar, Melchor; Rodríguez-Rodríguez, Eva

    2010-08-01

    The hypothesis of reverse epidemiology holds that some cardiovascular risk factors, such as obesity, hypercholesterolemia and hypertension, in the elderly or in some chronic diseases are not harmful but permit better survival. However, this phenomenon is controversial and the underlying reasons are poorly understood. To search for factors simultaneously linked to reverse epidemiology and to short or long term survival. We included 400 patients, older than 60 years, hospitalized in a general internal medicine unit; 61 died in hospital and 338 were followed up by telephone. Obesity, higher blood pressure and serum cholesterol, besides being related to lower mortality both in hospital and after discharge, were associated with better nutrition and functional capacity, less intense acute phase reaction and organ dysfunction, and lower incidence of high-mortality diseases such as dementia, pneumonia, sepsis or cancer. These associations may explain why obesity and other reverse epidemiology data are inversely related to mortality. Weight loss was related to mortality independently of BMI. Patients with BMI under 30 kg/m(2) who died in hospital showed more weight loss than those who survived; the lower the BMI, the greater the weight loss. In contrast, patients with BMI over 30 kg/m(2) who died in hospital gained more weight than those who survived; the higher the BMI, the greater the weight gain. In patients over 60 years of age admitted to an internal medicine ward, obesity did not show independent survival value, being displaced by other nutritional parameters, functional capacity, acute phase reaction, organ dysfunction and diseases with poor prognosis. Copyright 2009 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  7. Shared dosimetry error in epidemiological dose-response analyses

    International Nuclear Information System (INIS)

    Stram, Daniel O.; Preston, Dale L.; Sokolnikov, Mikhail; Napier, Bruce; Kopecky, Kenneth J.; Boice, John; Beck, Harold; Till, John; Bouville, Andre; Zeeb, Hajo

    2015-01-01

    Radiation dose reconstruction systems for large-scale epidemiological studies are sophisticated both in providing estimates of dose and in representing dosimetry uncertainty. For example, a computer program was used by the Hanford Thyroid Disease Study to provide 100 realizations of possible dose to study participants. The variation in realizations reflected the range of possible dose for each cohort member consistent with the data on dose determinates in the cohort. Another example is the Mayak Worker Dosimetry System 2013 which estimates both external and internal exposures and provides multiple realizations of 'possible' dose history to workers given dose determinants. This paper takes up the problem of dealing with complex dosimetry systems that provide multiple realizations of dose in an epidemiologic analysis. In this paper we derive expected scores and the information matrix for a model used widely in radiation epidemiology, namely the linear excess relative risk (ERR) model that allows for a linear dose response (risk in relation to radiation) and distinguishes between modifiers of background rates and of the excess risk due to exposure. We show that treating the mean dose for each individual (calculated by averaging over the realizations) as if it was true dose (ignoring both shared and unshared dosimetry errors) gives asymptotically unbiased estimates (i.e. the score has expectation zero) and valid tests of the null hypothesis that the ERR slope β is zero. Although the score is unbiased the information matrix (and hence the standard errors of the estimate of β) is biased for β≠0 when ignoring errors in dose estimates, and we show how to adjust the information matrix to remove this bias, using the multiple realizations of dose. The use of these methods in the context of several studies including, the Mayak Worker Cohort, and the U.S. Atomic Veterans Study, is discussed

  8. Glaucoma--diabetes of the brain: a radical hypothesis about its nature and pathogenesis.

    Science.gov (United States)

    Faiq, Muneeb A; Dada, Rima; Saluja, Daman; Dada, Tanuj

    2014-05-01

    Glaucoma is the leading cause of irreversible blindness characterized by irremediable loss of retinal ganglion cells. Its risk increases with progressing age and elevated intraocular pressure. Studies have established that glaucoma is a neurodegenerative disorder in which the damage involves many brain tissues from retina to the lateral geniculate nucleus. Despite lot of research, complete pathomechanism of glaucoma is not known and there is no treatment available except modification of intraocular pressure pharmacologically and/or surgically. We here present a hypothesis inspired by studies across many areas of molecular and clinical sciences in an integrative manner that leads to a uniquely unconventional understanding of this disorder. Our hypothesis postulates that glaucoma may possibly be the diabetes of the brain. Based on the remarkable similarities between glaucoma and diabetes we propose glaucoma also to be a type of diabetes. Glaucoma and diabetes share many aspects from various molecular mechanisms to involvement of insulin and possible use of antidiabetics in glaucoma therapy. Additionally, Alzheimer's disease has already been proposed to be diabetes type-3. We show that Alzheimer's disease is cerebral glaucoma and diabetes at the same time which, by transitive property of similarities, again leads to our hypothesis that glaucoma is diabetes of the brain. Our proposition may lead to appreciation of certain important facets of glaucoma which have previously not been given due consideration. It also may lead to an alternative classification of diabetes as pancreatic and brain diabetes thereby widening the vision arena of the understanding of both these disorders. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. The New Epidemiology--A Challenge to Health Administration. Issues in Epidemiology for Administration.

    Science.gov (United States)

    Crichton, Anne, Ed.; Neuhauser, Duncan, Ed.

    The role of epidemiology in health administration is considered in 11 articles, and three course descriptions and a bibliography are provided. Titles and authors include the following: "The Need for Creative Managerial Epidemiology" (Gary L. Filerman); "The Growing Role of Epidemiology in Health Administration" (Maureen M.…

  10. The impact of parenthood on environmental attitudes and behaviour: a longitudinal investigation of the legacy hypothesis.

    Science.gov (United States)

    Thomas, Gregory O; Fisher, Rose; Whitmarsh, Lorraine; Milfont, Taciano L; Poortinga, Wouter

    2018-01-01

    Willingness to engage in sustainable actions may be limited by the psychological distance of climate change. In this study, we test the legacy hypothesis , which holds that having children leads parents to consider the legacy left to offspring in respect of environmental quality. Using the Understanding Society dataset, a longitudinal survey representative of the UK population ( n  = 18,176), we assess how having children may change people's individual environmental attitudes and behaviour. Results indicate that having a new child is associated with a small decrease in the frequency of a few environmental behaviours. Only parents with already high environmental concern show a small increase in the desire to act more sustainably after the birth of their first child. Overall, the results do not provide evidence in support of the legacy hypothesis in terms of individual-level environmental attitudes and behaviours. We argue that the transition to parenthood is a time where concern is prioritised on the immediate wellbeing of the child and not on the future environmental threats.

  11. A Design Support Framework through Dynamic Deployment of Hypothesis and Verification in the Design Process

    Science.gov (United States)

    Nomaguch, Yutaka; Fujita, Kikuo

    This paper proposes a design support framework, named DRIFT (Design Rationale Integration Framework of Three layers), which dynamically captures and manages hypothesis and verification in the design process. A core of DRIFT is a three-layered design process model of action, model operation and argumentation. This model integrates various design support tools and captures design operations performed on them. Action level captures the sequence of design operations. Model operation level captures the transition of design states, which records a design snapshot over design tools. Argumentation level captures the process of setting problems and alternatives. The linkage of three levels enables to automatically and efficiently capture and manage iterative hypothesis and verification processes through design operations over design tools. In DRIFT, such a linkage is extracted through the templates of design operations, which are extracted from the patterns embeded in design tools such as Design-For-X (DFX) approaches, and design tools are integrated through ontology-based representation of design concepts. An argumentation model, gIBIS (graphical Issue-Based Information System), is used for representing dependencies among problems and alternatives. A mechanism of TMS (Truth Maintenance System) is used for managing multiple hypothetical design stages. This paper also demonstrates a prototype implementation of DRIFT and its application to a simple design problem. Further, it is concluded with discussion of some future issues.

  12. Life Shocks and Crime: A Test of the “Turning Point” Hypothesis

    Science.gov (United States)

    Noonan, Kelly; Reichman, Nancy E.; Schwartz-Soicher, Ofira

    2012-01-01

    Other researchers have posited that important events in men’s lives—such as employment, marriage, and parenthood—strengthen their social ties and lead them to refrain from crime. A challenge in empirically testing this hypothesis has been the issue of self-selection into life transitions. This study contributes to this literature by estimating the effects of an exogenous life shock on crime. We use data from the Fragile Families and Child Wellbeing Study, augmented with information from hospital medical records, to estimate the effects of the birth of a child with a severe health problem on the likelihood that the infant’s father engages in illegal activities. We conduct a number of auxiliary analyses to examine exogeneity assumptions. We find that having an infant born with a severe health condition increases the likelihood that the father is convicted of a crime in the three-year period following the birth of the child, and at least part of the effect appears to operate through work and changes in parental relationships. These results provide evidence that life events can cause crime and, as such, support the “turning point” hypothesis. PMID:21660628

  13. Life shocks and crime: a test of the "turning point" hypothesis.

    Science.gov (United States)

    Corman, Hope; Noonan, Kelly; Reichman, Nancy E; Schwartz-Soicher, Ofira

    2011-08-01

    Other researchers have posited that important events in men's lives-such as employment, marriage, and parenthood-strengthen their social ties and lead them to refrain from crime. A challenge in empirically testing this hypothesis has been the issue of self-selection into life transitions. This study contributes to this literature by estimating the effects of an exogenous life shock on crime. We use data from the Fragile Families and Child Wellbeing Study, augmented with information from hospital medical records, to estimate the effects of the birth of a child with a severe health problem on the likelihood that the infant's father engages in illegal activities. We conduct a number of auxiliary analyses to examine exogeneity assumptions. We find that having an infant born with a severe health condition increases the likelihood that the father is convicted of a crime in the three-year period following the birth of the child, and at least part of the effect appears to operate through work and changes in parental relationships. These results provide evidence that life events can cause crime and, as such, support the "turning point" hypothesis.

  14. TESTS OF THE PLANETARY HYPOTHESIS FOR PTFO 8-8695b

    International Nuclear Information System (INIS)

    Yu, Liang; Winn, Joshua N.; Rappaport, Saul; Dai, Fei; Triaud, Amaury H. M. J.; Gillon, Michaël; Delrez, Laetitia; Jehin, Emmanuel; Lendl, Monika; Albrecht, Simon; Bieryla, Allyson; Holman, Matthew J.; Montet, Benjamin T.; Hillenbrand, Lynne; Howard, Andrew W.; Huang, Chelsea X.; Isaacson, Howard; Sanchis-Ojeda, Roberto; Muirhead, Philip

    2015-01-01

    The T Tauri star PTFO 8-8695 exhibits periodic fading events that have been interpreted as the transits of a giant planet on a precessing orbit. Here we present three tests of the planet hypothesis. First, we sought evidence for the secular changes in light-curve morphology that are predicted to be a consequence of orbital precession. We observed 28 fading events spread over several years and did not see the expected changes. Instead, we found that the fading events are not strictly periodic. Second, we attempted to detect the planet's radiation, based on infrared observations spanning the predicted times of occultations. We ruled out a signal of the expected amplitude. Third, we attempted to detect the Rossiter–McLaughlin effect by performing high-resolution spectroscopy throughout a fading event. No effect was seen at the expected level, ruling out most (but not all) possible orientations for the hypothetical planetary orbit. Our spectroscopy also revealed strong, time-variable, high-velocity Hα and Ca H and K emission features. All these observations cast doubt on the planetary hypothesis, and suggest instead that the fading events represent starspots, eclipses by circumstellar dust, or occultations of an accretion hotspot

  15. GHG emissions, GDP growth and the Kyoto Protocol: A revisit of Environmental Kuznets Curve hypothesis

    International Nuclear Information System (INIS)

    Huang Weiming; Lee, Grace W.M.; Wu Chihcheng

    2008-01-01

    The Kyoto Protocol attempts through political negotiations to guide participating industrialized countries' greenhouse gas (GHG) emissions from a positive growing trend, to reach a peak point (or turning point), and then be reduced to a negative growth. That means the relationship between decreasing GHG emissions and economic growth may be described by an inverted-U curve (or called a bell-shaped curve), which is consistent with the concept of the Environmental Kuznets Curve (EKC) hypothesis. This research observed that the economic development and GHG emissions in Economies in Transition (EITs) exhibit a hockey-stick curve trend (or called quasi-L-shape curve), that also generates a lot of 'hot air' which is significant to the implementation of the Kyoto Protocol. In addition, through the analysis of single-country time series data and GDP data, this research demonstrated that statistical data for most of the Annex II countries do not possess evidence that supports the EKC hypothesis for GHG emissions. The results from this study also indicated that the 38 industrialized countries are unable to meet their targets under the Kyoto Protocol within the specified time period, which are probably caused by the econometric method's inability to predict accurately the extents and development of innovative technologies and Clean Development Mechanism (CDM) projects. If the international community truly wants to reduce the GHG emissions, the effectiveness of the existing international framework for emissions reduction needs to be reconsidered seriously, and the global cooperation mechanism also needs to be greatly enhanced

  16. Mobile DNA and the TE-Thrust hypothesis: supporting evidence from the primates

    Directory of Open Access Journals (Sweden)

    Oliver Keith R

    2011-05-01

    Full Text Available Abstract Transposable elements (TEs are increasingly being recognized as powerful facilitators of evolution. We propose the TE-Thrust hypothesis to encompass TE-facilitated processes by which genomes self-engineer coding, regulatory, karyotypic or other genetic changes. Although TEs are occasionally harmful to some individuals, genomic dynamism caused by TEs can be very beneficial to lineages. This can result in differential survival and differential fecundity of lineages. Lineages with an abundant and suitable repertoire of TEs have enhanced evolutionary potential and, if all else is equal, tend to be fecund, resulting in species-rich adaptive radiations, and/or they tend to undergo major evolutionary transitions. Many other mechanisms of genomic change are also important in evolution, and whether the evolutionary potential of TE-Thrust is realized is heavily dependent on environmental and ecological factors. The large contribution of TEs to evolutionary innovation is particularly well documented in the primate lineage. In this paper, we review numerous cases of beneficial TE-caused modifications to the genomes of higher primates, which strongly support our TE-Thrust hypothesis.

  17. Nutrition transition and food sustainability.

    Science.gov (United States)

    Belahsen, Rekia

    2014-08-01

    The aim of the present paper is to review nutrition transition (NT) ongoing in low and middle income countries and the associated dietary changes. NT is accompanied by demographic and epidemiological transition associated with economic development and urbanisation. In these countries, while the problems of hunger and undernourishment persist, there is an escalation of diet-related non-communicable diseases; making them face both problems of malnutrition, under and overnutrition. Indeed, in addition to protein energy malnutrition underweight and micronutrient deficiencies affect a high proportion of children and women. Conversely, changes in dietary habits and physical activity patterns have led to emergence of chronic diseases such as obesity, diabetes, hypertension, stroke, hyperlipidaemia, CHD and cancer. One possible explanation of weight gain and its associated health consequences is the trend of the consumption of already prepared meals and the restaurants that are in continuous development leading to high consumption of foods rich in sugar and fat. The health problems associated with NT have not spared populations in the Mediterranean area where the type of diet is reported to be healthy and to protect against cardiovascular risks. This is seen in North Africa that belongs also to the Mediterranean basin, where the nutritional situation raises the problem of traditional foods sustainability. Accurate nutritional policy and education are needed to redress the effects of malnutrition related to NT on health.

  18. A Hypothesis-Driven Approach to Site Investigation

    Science.gov (United States)

    Nowak, W.

    2008-12-01

    Variability of subsurface formations and the scarcity of data lead to the notion of aquifer parameters as geostatistical random variables. Given an information need and limited resources for field campaigns, site investigation is often put into the context of optimal design. In optimal design, the types, numbers and positions of samples are optimized under case-specific objectives to meet the information needs. Past studies feature optimal data worth (balancing maximum financial profit in an engineering task versus the cost of additional sampling), or aim at a minimum prediction uncertainty of stochastic models for a prescribed investigation budget. Recent studies also account for other sources of uncertainty outside the hydrogeological range, such as uncertain toxicity, ingestion and behavioral parameters of the affected population when predicting the human health risk from groundwater contaminations. The current study looks at optimal site investigation from a new angle. Answering a yes/no question under uncertainty directly requires recasting the original question as a hypothesis test. Otherwise, false confidence in the resulting answer would be pretended. A straightforward example is whether a recent contaminant spill will cause contaminant concentrations in excess of a legal limit at a nearby drinking water well. This question can only be answered down to a specified chance of error, i.e., based on the significance level used in hypothesis tests. Optimal design is placed into the hypothesis-driven context by using the chance of providing a false yes/no answer as new criterion to be minimized. Different configurations apply for one-sided and two-sided hypothesis tests. If a false answer entails financial liability, the hypothesis-driven context can be re-cast in the context of data worth. The remaining difference is that failure is a hard constraint in the data worth context versus a monetary punishment term in the hypothesis-driven context. The basic principle

  19. Prospective detection of large prediction errors: a hypothesis testing approach

    International Nuclear Information System (INIS)

    Ruan, Dan

    2010-01-01

    Real-time motion management is important in radiotherapy. In addition to effective monitoring schemes, prediction is required to compensate for system latency, so that treatment can be synchronized with tumor motion. However, it is difficult to predict tumor motion at all times, and it is critical to determine when large prediction errors may occur. Such information can be used to pause the treatment beam or adjust monitoring/prediction schemes. In this study, we propose a hypothesis testing approach for detecting instants corresponding to potentially large prediction errors in real time. We treat the future tumor location as a random variable, and obtain its empirical probability distribution with the kernel density estimation-based method. Under the null hypothesis, the model probability is assumed to be a concentrated Gaussian centered at the prediction output. Under the alternative hypothesis, the model distribution is assumed to be non-informative uniform, which reflects the situation that the future position cannot be inferred reliably. We derive the likelihood ratio test (LRT) for this hypothesis testing problem and show that with the method of moments for estimating the null hypothesis Gaussian parameters, the LRT reduces to a simple test on the empirical variance of the predictive random variable. This conforms to the intuition to expect a (potentially) large prediction error when the estimate is associated with high uncertainty, and to expect an accurate prediction when the uncertainty level is low. We tested the proposed method on patient-derived respiratory traces. The 'ground-truth' prediction error was evaluated by comparing the prediction values with retrospective observations, and the large prediction regions were subsequently delineated by thresholding the prediction errors. The receiver operating characteristic curve was used to describe the performance of the proposed hypothesis testing method. Clinical implication was represented by miss

  20. [Causal analysis approaches in epidemiology].

    Science.gov (United States)

    Dumas, O; Siroux, V; Le Moual, N; Varraso, R

    2014-02-01

    Epidemiological research is mostly based on observational studies. Whether such studies can provide evidence of causation remains discussed. Several causal analysis methods have been developed in epidemiology. This paper aims at presenting an overview of these methods: graphical models, path analysis and its extensions, and models based on the counterfactual approach, with a special emphasis on marginal structural models. Graphical approaches have been developed to allow synthetic representations of supposed causal relationships in a given problem. They serve as qualitative support in the study of causal relationships. The sufficient-component cause model has been developed to deal with the issue of multicausality raised by the emergence of chronic multifactorial diseases. Directed acyclic graphs are mostly used as a visual tool to identify possible confounding sources in a study. Structural equations models, the main extension of path analysis, combine a system of equations and a path diagram, representing a set of possible causal relationships. They allow quantifying direct and indirect effects in a general model in which several relationships can be tested simultaneously. Dynamic path analysis further takes into account the role of time. The counterfactual approach defines causality by comparing the observed event and the counterfactual event (the event that would have been observed if, contrary to the fact, the subject had received a different exposure than the one he actually received). This theoretical approach has shown limits of traditional methods to address some causality questions. In particular, in longitudinal studies, when there is time-varying confounding, classical methods (regressions) may be biased. Marginal structural models have been developed to address this issue. In conclusion, "causal models", though they were developed partly independently, are based on equivalent logical foundations. A crucial step in the application of these models is the

  1. The Link between Health Complaints and Wind Turbines: Support for the Nocebo Expectations Hypothesis.

    Science.gov (United States)

    Crichton, Fiona; Chapman, Simon; Cundy, Tim; Petrie, Keith J

    2014-01-01

    The worldwide expansion of wind energy has met with opposition based on concerns that the infrasound generated by wind turbines causes health problems in nearby residents. In this paper, we argue that health complaints are more likely to be explained by the nocebo response, whereby adverse effects are generated by negative expectations. When individuals expect a feature of their environment or medical treatment to produce illness or symptoms, then this may start a process where the individual looks for symptoms or signs of illness to confirm these negative expectations. As physical symptoms are common in healthy people, there is considerable scope for people to match symptoms with their negative expectations. To support this hypothesis, we draw an evidence from experimental studies that show that, during exposure to wind farm sound, expectations about infrasound can influence symptoms and mood in both positive and negative directions, depending on how expectations are framed. We also consider epidemiological work showing that health complaints have primarily been located in areas that have received the most negative publicity about the harmful effects of turbines. The social aspect of symptom complaints in a community is also discussed as an important process in increasing symptom reports. Media stories, publicity, or social discourse about the reported health effects of wind turbines are likely to trigger reports of similar symptoms, regardless of exposure. Finally, we present evidence to show that the same pattern of health complaints following negative information about wind turbines has also been found in other types of environmental concerns and scares.

  2. Alzheimer disease and cognitive impairment associated with diabetes mellitus type 2: associations and a hypothesis.

    Science.gov (United States)

    Domínguez, R O; Pagano, M A; Marschoff, E R; González, S E; Repetto, M G; Serra, J A

    2014-01-01

    Epidemiological studies have demonstrated that patients with diabetes mellitus have an increased risk of developing Alzheimer disease, but the relationship between the 2 entities is not clear. Both diseases exhibit similar metabolic abnormalities: disordered glucose metabolism, abnormal insulin receptor signalling and insulin resistance, oxidative stress, and structural abnormalities in proteins and β-amyloid deposits. Different hypotheses have emerged from experimental work in the last two decades. One of the most comprehensive relates the microvascular damage in diabetic polyneuritis with the central nervous system changes occurring in Alzheimer disease. Another hypothesis considers that cognitive impairment in both diabetes and Alzheimer disease is linked to a state of systemic oxidative stress. Recently, attenuation of cognitive impairment and normalisation of values in biochemical markers for oxidative stress were found in patients with Alzheimer disease and concomitant diabetes. Antidiabetic drugs may have a beneficial effect on glycolysis and its end products, and on other metabolic alterations. Diabetic patients are at increased risk for developing Alzheimer disease, but paradoxically, their biochemical alterations and cognitive impairment are less pronounced than in groups of dementia patients without diabetes. A deeper understanding of interactions between the pathogenic processes of both entities may lead to new therapeutic strategies that would slow or halt the progression of impairment. Copyright © 2013 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.

  3. A Hypothesis Concerning a Potential Involvement of Ceramide in Apoptosis and Acantholysis Induced by Pemphigus Autoantibodies

    Directory of Open Access Journals (Sweden)

    Wendy B. Bollag

    2010-01-01

    Full Text Available Autoimmune diseases affect more than 50 million Americans, resulting in significant healthcare costs. Most autoimmune diseases occur sporadically; however, endemic pemphigus foliaceus (EPF is an autoimmune skin disease localized to specific geographic loci. EPF, and the related diseases pemphigus vulgaris (PV and pemphigus foliaceus (PF, are characterized by skin lesions and autoantibodies to molecules found on epidermal keratinocytes. A variant of EPF in patients from El Bagre, Colombia, South America, has recently been reported to be distinct from previously described loci in Brazil and Tunisia epidemiologically and immunologically. As in PF and EPF, El Bagre EPF patients exhibit autoantibodies towards desmoglein-1, a cell adhesion molecule critical for maintaining epidermal integrity. An association of El Bagre EPF with sun exposure has been detected, and ultraviolet irradiation also exacerbates symptoms in PV, PF and EPF. Our hypothesis is that: (1 the autoantibodies generate pathology through an alteration in ceramide metabolism in targeted keratinocytes, resulting in apoptosis and/or cell death and acantholysis, but only when the cell's ability to metabolize ceramide is exceeded, and (2 apoptosis in response to this altered ceramide metabolism is initiated and/or exacerbated by other agents that increase ceramide levels, such as cytokines, ultraviolet irradiation, and senescence.

  4. A hypothesis concerning a potential involvement of ceramide in apoptosis and acantholysis induced by pemphigus autoantibodies.

    Science.gov (United States)

    Bollag, Wendy B

    2010-01-01

    Autoimmune diseases affect more than 50 million Americans, resulting in significant healthcare costs. Most autoimmune diseases occur sporadically; however, endemic pemphigus foliaceus (EPF) is an autoimmune skin disease localized to specific geographic loci. EPF, and the related diseases pemphigus vulgaris (PV) and pemphigus foliaceus (PF), are characterized by skin lesions and autoantibodies to molecules found on epidermal keratinocytes. A variant of EPF in patients from El Bagre, Colombia, South America, has recently been reported to be distinct from previously described loci in Brazil and Tunisia epidemiologically and immunologically. As in PF and EPF, El Bagre EPF patients exhibit autoantibodies towards desmoglein-1, a cell adhesion molecule critical for maintaining epidermal integrity. An association of El Bagre EPF with sun exposure has been detected, and ultraviolet irradiation also exacerbates symptoms in PV, PF and EPF. Our hypothesis is that: (1) the autoantibodies generate pathology through an alteration in ceramide metabolism in targeted keratinocytes, resulting in apoptosis and/or cell death and acantholysis, but only when the cell's ability to metabolize ceramide is exceeded, and (2) apoptosis in response to this altered ceramide metabolism is initiated and/or exacerbated by other agents that increase ceramide levels, such as cytokines, ultraviolet irradiation, and senescence.

  5. Mismatch or cumulative stress : Toward an integrated hypothesis of programming effects

    NARCIS (Netherlands)

    Nederhof, Esther; Schmidt, Mathias V.

    2012-01-01

    This paper integrates the cumulative stress hypothesis with the mismatch hypothesis, taking into account individual differences in sensitivity to programming. According to the cumulative stress hypothesis, individuals are more likely to suffer from disease as adversity accumulates. According to the

  6. Epidemiology of extremity fractures in the Netherlands

    NARCIS (Netherlands)

    Beerekamp, M. S. H.; de Muinck Keizer, R. J. O.; Schep, N. W. L.; Ubbink, D. T.; Panneman, M. J. M.; Goslings, J. C.

    2017-01-01

    Insight in epidemiologic data of extremity fractures is relevant to identify people at risk. By analyzing age- and gender specific fracture incidence and treatment patterns we may adjust future policy, take preventive measures and optimize health care management. Current epidemiologic data on

  7. Complex epidemiological approach to human mutagenesis

    International Nuclear Information System (INIS)

    Czeizel, A.

    1980-01-01

    The main characteristics of the epidemiological approach are summarised and the criteria discussed for the adoption of this approach for the detection of human mutagenesis. Mutation monitoring systems are described and results of epidemiological studies of higher risk populations are presented. (C.F.)

  8. Maritim epidemiologi på Supercourse

    DEFF Research Database (Denmark)

    Jensen, Olaf

    2015-01-01

    Maritim epidemiologi er nu kommet med i samlingen af undervisningsmidler på ”Supercourse”. Der er oprettet en særlig mappe med Maritime Epidemiology og alle der har gode bidrag inden for området opfordres hermed til at publicere her. Supercourse er en samling af foredrag beregnet til at være en r...

  9. Retrospective study of epidemiological, clinicopathological and ...

    African Journals Online (AJOL)

    Retrospective study of epidemiological, clinicopathological and biological profils of 62 colorectal cancers cases in Jijel provence (Algeria) ... Our results were often compatible with the available literature and may provide reliable and relevant data on this disease. Key words: Colorectal cancer; Epidemiology; Therapy; ...

  10. Epidemiology, diagnosis and management of food allergy

    NARCIS (Netherlands)

    Le, T.T.M.

    2013-01-01

    This thesis describes the epidemiology, diagnosis and management of food allergy. Epidemiology This thesis shows that the prevalence of self-reported adverse food reactions in children and adults was high: 17-25% for all foods and 10-11% for 24 preselected, so-called priority foods. The prevalence

  11. Nephrogenic systemic fibrosis: epidemiology update

    DEFF Research Database (Denmark)

    Marckmann, P.

    2008-01-01

    Purpose of review The aim of this article is to outline the history of nephrogenic systemic fibrosis, a new and serious disease of patients with renal failure, and to give an update on its aetiology and prevalence. Recent findings Epidemiological and histochemical studies demonstrated....... Increasingly poor renal function, aberrations in calcium-phosphate metabolism and erythropoietin treatment seem to increase the risk of the disease and its severity. Up to 25-30% of patients with renal failure exposed to gadolinium-based contrast agents may develop nephrogenic systemic disease. The figure...... that gadolinium-containing contrast agents used for magnetic resonance imaging have an essential causative role in most, if not all, cases of nephrogenic systemic fibrosis. One particular agent, gadodiamide, caused the majority of cases, but gadopentetate dimeglumine has also been implicated in several cases...

  12. [Scientific journalism and epidemiological risk].

    Science.gov (United States)

    Luiz, Olinda do Carmo

    2007-01-01

    The importance of the communications media in the construction of symbols has been widely acknowledged. Many of the articles on health published in the daily newspapers mention medical studies, sourced from scientific publications focusing on new risks. The disclosure of risk studies in the mass media is also a topic for editorials and articles in scientific journals, focusing the problem of distortions and the appearance of contradictory news items. The purpose of this paper is to explore the meaning and content of disclosing scientific risk studies in large-circulation daily newspapers, analyzing news items published in Brazil and the scientific publications used as their sources during 2000. The "risk" is presented in the scientific research projects as a "black box" in the meaning of Latour, with the news items downplaying scientific disputes and underscoring associations between behavioral habits and the occurrence of diseases, emphasizing individual aspects of the epidemiological approach, to the detriment of the group.

  13. Epidemiology of acute wrist trauma

    DEFF Research Database (Denmark)

    Larsen, C F; Lauritsen, Jens

    1993-01-01

    Epidemiological data on wrist injuries in a population can be used for planning by applying them to criteria for care and thus deriving estimates of provisions for care according to currently desirable standards. In a 1-year study all patients > or = 15 years with acute wrist trauma and treated...... in the emergency room were examined according to an algorithm until a diagnosis was established. The overall incidence of wrist trauma was 69 per 10,000 inhabitants per year. Incidence of wrist trauma requiring x-ray examination was 58 per 10,000 per year. The incidence of distal radius fractures was 27 per 10...... using data from a population-based study. A completeness rate of 0.56 (95% confidence interval: 0.31-0.78) was found. An x-ray had been taken for all patients reporting a fracture thus justifying the use of fractures as an incidence measure when comparing groups of patients with wrist trauma....

  14. Epidemiology of Haemophilus ducreyi Infections.

    Science.gov (United States)

    González-Beiras, Camila; Marks, Michael; Chen, Cheng Y; Roberts, Sally; Mitjà, Oriol

    2016-01-01

    The global epidemiology of Haemophilus ducreyi infections is poorly documented because of difficulties in confirming microbiological diagnoses. We evaluated published data on the proportion of genital and nongenital skin ulcers caused by H. ducreyi before and after introduction of syndromic management for genital ulcer disease (GUD). Before 2000, the proportion of GUD caused by H. ducreyi ranged from 0.0% to 69.0% (35 studies in 25 countries). After 2000, the proportion ranged from 0.0% to 15.0% (14 studies in 13 countries). In contrast, H. ducreyi has been recently identified as a causative agent of skin ulcers in children in the tropical regions; proportions ranged from 9.0% to 60.0% (6 studies in 4 countries). We conclude that, although there has been a sustained reduction in the proportion of GUD caused by H. ducreyi, this bacterium is increasingly recognized as a major cause of nongenital cutaneous ulcers.

  15. Worldwide molecular epidemiology of HIV

    Directory of Open Access Journals (Sweden)

    Henry I Z Requejo

    2006-04-01

    Full Text Available Human immunodeficiency virus (HIV is the worldwide disseminated causative agent of acquired immunodeficiency syndrome (AIDS. HIV is a member of the Lentivirus genus of Retroviridae family and is grouped in two types named HIV-1 and HIV-2. These viruses have a notable ability to mutate and adapt to the new conditions of human environment. A large incidence of errors at the transcriptional level results in changes on the genetic bases during the reproductive cycle. The elevated genomic variability of HIV has carried important implications for the diagnosis, treatment and prevention as well as epidemiologic investigations. The present review describes important definitions and geographical distribution of subtypes, circulating recombinant forms and other genomic variations of HIV. The present study aimed at leading students of Biomedical Sciences and public health laboratory staff guidance to general and specific knowledge about the genomic variability of the HIV.

  16. EPIDEMIOLOGICAL EVALUATION OF COLORECTAL CANCER

    Directory of Open Access Journals (Sweden)

    B. Shafayan M. Keyhani

    2003-07-01

    Full Text Available This study was carried out to analyze certain epidemiological variations in Iranian patients with colorectal cancer. (CRC: From March 1981 up to March 1993, 103 patients were analyzed retrospectively for age, gender, marital state, job, nutritional habits, presenting symptoms and histopathological features. Most of the patients with colorectal cancer were male, age range 20-75 (mean 56, 25.4 percent were long-term smokers and bleeding was the most common symptom. The rectum was the most common site and moderately differentiated carcinoma was considered as the main common histopathological variety. In conclusion, increasing incidence of colorectal cancer in younger Iranian population, below 30 and late admission and diagnosis were the main findings in the present study necessitating screening programs with annual fecal occult blood tests in high risk families.

  17. An omnibus test for the global null hypothesis.

    Science.gov (United States)

    Futschik, Andreas; Taus, Thomas; Zehetmayer, Sonja

    2018-01-01

    Global hypothesis tests are a useful tool in the context of clinical trials, genetic studies, or meta-analyses, when researchers are not interested in testing individual hypotheses, but in testing whether none of the hypotheses is false. There are several possibilities how to test the global null hypothesis when the individual null hypotheses are independent. If it is assumed that many of the individual null hypotheses are false, combination tests have been recommended to maximize power. If, however, it is assumed that only one or a few null hypotheses are false, global tests based on individual test statistics are more powerful (e.g. Bonferroni or Simes test). However, usually there is no a priori knowledge on the number of false individual null hypotheses. We therefore propose an omnibus test based on cumulative sums of the transformed p-values. We show that this test yields an impressive overall performance. The proposed method is implemented in an R-package called omnibus.

  18. Discrete causal theory emergent spacetime and the causal metric hypothesis

    CERN Document Server

    Dribus, Benjamin F

    2017-01-01

    This book evaluates and suggests potentially critical improvements to causal set theory, one of the best-motivated approaches to the outstanding problems of fundamental physics. Spacetime structure is of central importance to physics beyond general relativity and the standard model. The causal metric hypothesis treats causal relations as the basis of this structure. The book develops the consequences of this hypothesis under the assumption of a fundamental scale, with smooth spacetime geometry viewed as emergent. This approach resembles causal set theory, but differs in important ways; for example, the relative viewpoint, emphasizing relations between pairs of events, and relationships between pairs of histories, is central. The book culminates in a dynamical law for quantum spacetime, derived via generalized path summation.

  19. A test of the domain-specific acculturation strategy hypothesis.

    Science.gov (United States)

    Miller, Matthew J; Yang, Minji; Lim, Robert H; Hui, Kayi; Choi, Na-Yeun; Fan, Xiaoyan; Lin, Li-Ling; Grome, Rebekah E; Farrell, Jerome A; Blackmon, Sha'kema

    2013-01-01

    Acculturation literature has evolved over the past several decades and has highlighted the dynamic ways in which individuals negotiate experiences in multiple cultural contexts. The present study extends this literature by testing M. J. Miller and R. H. Lim's (2010) domain-specific acculturation strategy hypothesis-that individuals might use different acculturation strategies (i.e., assimilated, bicultural, separated, and marginalized strategies; J. W. Berry, 2003) across behavioral and values domains-in 3 independent cluster analyses with Asian American participants. Present findings supported the domain-specific acculturation strategy hypothesis as 67% to 72% of participants from 3 independent samples using different strategies across behavioral and values domains. Consistent with theory, a number of acculturation strategy cluster group differences emerged across generational status, acculturative stress, mental health symptoms, and attitudes toward seeking professional psychological help. Study limitations and future directions for research are discussed.

  20. Teen Fertility and Gender Inequality in Education: A Contextual Hypothesis

    Directory of Open Access Journals (Sweden)

    C. Shannon Stokes

    2004-12-01

    Full Text Available Previous studies in developed countries have found a micro-level association between teenage fertility and girls' educational attainment but researchers still debate the policy implications of these associations. First, are these associations causal? Second, are they substantively important enough, at the macro-level, to warrant policy attention? In other words, how much would policy efforts to reduce unintended pregnancy among teens pay off in terms of narrowing national gender gaps in educational attainment? Third, under what contexts are these payoffs likely to be important? This paper focuses on the latter two questions. We begin by proposing a contextual hypothesis to explain cross-national variation in the gender-equity payoffs from reducing unintended teen fertility. We then test this hypothesis, using DHS data from 38 countries.

  1. The functional matrix hypothesis revisited. 3. The genomic thesis.

    Science.gov (United States)

    Moss, M L

    1997-09-01

    Although the initial versions of the functional matrix hypothesis (FMH) theoretically posited the ontogenetic primacy of "function," it is only in recent years that advances in the morphogenetic, engineering, and computer sciences provided an integrated experimental and numerical data base that permitted recent significant revisions of the FMH--revisions that strongly support the primary role of function in craniofacial growth and development. Acknowledging that the currently dominant scientific paradigm suggests that genomic, instead of epigenetic (functional) factors, regulate (cause, control) such growth, an analysis of this continuing controversy was deemed useful. Accordingly the method of dialectical analysis, is employed, stating a thesis, an antithesis, and a resolving synthesis based primarily on an extensive review of the pertinent current literature. This article extensively reviews the genomic hypothesis and offers a critique intended to remove some of the unintentional conceptual obscurantism that has recently come to surround it.

  2. Amyloid cascade hypothesis: Pathogenesis and therapeutic strategies in Alzheimer's disease.

    Science.gov (United States)

    Barage, Sagar H; Sonawane, Kailas D

    2015-08-01

    Alzheimer's disease is an irreversible, progressive neurodegenerative disorder. Various therapeutic approaches are being used to improve the cholinergic neurotransmission, but their role in AD pathogenesis is still unknown. Although, an increase in tau protein concentration in CSF has been described in AD, but several issues remains unclear. Extensive and accurate analysis of CSF could be helpful to define presence of tau proteins in physiological conditions, or released during the progression of neurodegenerative disease. The amyloid cascade hypothesis postulates that the neurodegeneration in AD caused by abnormal accumulation of amyloid beta (Aβ) plaques in various areas of the brain. The amyloid hypothesis has continued to gain support over the last two decades, particularly from genetic studies. Therefore, current research progress in several areas of therapies shall provide an effective treatment to cure this devastating disease. This review critically evaluates general biochemical and physiological functions of Aβ directed therapeutics and their relevance. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Neuromuscular deficits after peripheral joint injury: a neurophysiological hypothesis.

    Science.gov (United States)

    Ward, Sarah; Pearce, Alan J; Pietrosimone, Brian; Bennell, Kim; Clark, Ross; Bryant, Adam L

    2015-03-01

    In addition to biomechanical disturbances, peripheral joint injuries (PJIs) can also result in chronic neuromuscular alterations due in part to loss of mechanoreceptor-mediated afferent feedback. An emerging perspective is that PJI should be viewed as a neurophysiological dysfunction, not simply a local injury. Neurophysiological and neuroimaging studies have provided some evidence for central nervous system (CNS) reorganization at both the cortical and spinal levels after PJI. The novel hypothesis proposed is that CNS reorganization is the underlying mechanism for persisting neuromuscular deficits after injury, particularly muscle weakness. There is a lack of direct evidence to support this hypothesis, but future studies utilizing force-matching tasks with superimposed transcranial magnetic stimulation may be help clarify this notion. © 2014 Wiley Periodicals, Inc.

  4. The estrogen hypothesis of schizophrenia implicates glucose metabolism

    DEFF Research Database (Denmark)

    Olsen, Line; Hansen, Thomas; Jakobsen, Klaus D

    2008-01-01

    expression studies have indicated an equally large set of candidate genes that only partially overlap linkage genes. A thorough assessment, beyond the resolution of current GWA studies, of the disease risk conferred by the numerous schizophrenia candidate genes is a daunting and presently not feasible task....... We undertook these challenges by using an established clinical paradigm, the estrogen hypothesis of schizophrenia, as the criterion to select candidates among the numerous genes experimentally implicated in schizophrenia. Bioinformatic tools were used to build and priorities the signaling networks...... implicated by the candidate genes resulting from the estrogen selection. We identified ten candidate genes using this approach that are all active in glucose metabolism and particularly in the glycolysis. Thus, we tested the hypothesis that variants of the glycolytic genes are associated with schizophrenia...

  5. Energy prices, multiple structural breaks, and efficient market hypothesis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chien-Chiang; Lee, Jun-De [Department of Applied Economics, National Chung Hsing University, Taichung (China)

    2009-04-15

    This paper investigates the efficient market hypothesis using total energy price and four kinds of various disaggregated energy prices - coal, oil, gas, and electricity - for OECD countries over the period 1978-2006. We employ a highly flexible panel data stationarity test of Carrion-i-Silvestre et al. [Carrion-i-Silvestre JL, Del Barrio-Castro T, Lopez-Bazo E. Breaking the panels: an application to GDP per capita. J Econometrics 2005;8:159-75], which incorporates multiple shifts in level and slope, thereby controlling for cross-sectional dependence through bootstrap methods. Overwhelming evidence in favor of the broken stationarity hypothesis is found, implying that energy prices are not characterized by an efficient market. Thus, it shows the presence of profitable arbitrage opportunities among energy prices. The estimated breaks are meaningful and coincide with the most critical events which affected the energy prices. (author)

  6. Energy prices, multiple structural breaks, and efficient market hypothesis

    International Nuclear Information System (INIS)

    Lee, Chien-Chiang; Lee, Jun-De

    2009-01-01

    This paper investigates the efficient market hypothesis using total energy price and four kinds of various disaggregated energy prices - coal, oil, gas, and electricity - for OECD countries over the period 1978-2006. We employ a highly flexible panel data stationarity test of Carrion-i-Silvestre et al. [Carrion-i-Silvestre JL, Del Barrio-Castro T, Lopez-Bazo E. Breaking the panels: an application to GDP per capita. J Econometrics 2005;8:159-75], which incorporates multiple shifts in level and slope, thereby controlling for cross-sectional dependence through bootstrap methods. Overwhelming evidence in favor of the broken stationarity hypothesis is found, implying that energy prices are not characterized by an efficient market. Thus, it shows the presence of profitable arbitrage opportunities among energy prices. The estimated breaks are meaningful and coincide with the most critical events which affected the energy prices. (author)

  7. The hubris hypothesis: The downside of comparative optimism displays.

    Science.gov (United States)

    Hoorens, Vera; Van Damme, Carolien; Helweg-Larsen, Marie; Sedikides, Constantine

    2017-04-01

    According to the hubris hypothesis, observers respond more unfavorably to individuals who express their positive self-views comparatively than to those who express their positive self-views non-comparatively, because observers infer that the former hold a more disparaging view of others and particularly of observers. Two experiments extended the hubris hypothesis in the domain of optimism. Observers attributed less warmth (but not less competence) to, and showed less interest in affiliating with, an individual displaying comparative optimism (the belief that one's future will be better than others' future) than with an individual displaying absolute optimism (the belief that one's future will be good). Observers responded differently to individuals displaying comparative versus absolute optimism, because they inferred that the former held a gloomier view of the observers' future. Consistent with previous research, observers still attributed more positive traits to a comparative or absolute optimist than to a comparative or absolute pessimist. Copyright © 2016. Published by Elsevier Inc.

  8. Applicability of Taylor's hypothesis in thermally driven turbulence

    Science.gov (United States)

    Kumar, Abhishek; Verma, Mahendra K.

    2018-04-01

    In this paper, we show that, in the presence of large-scale circulation (LSC), Taylor's hypothesis can be invoked to deduce the energy spectrum in thermal convection using real-space probes, a popular experimental tool. We perform numerical simulation of turbulent convection in a cube and observe that the velocity field follows Kolmogorov's spectrum (k-5/3). We also record the velocity time series using real-space probes near the lateral walls. The corresponding frequency spectrum exhibits Kolmogorov's spectrum (f-5/3), thus validating Taylor's hypothesis with the steady LSC playing the role of a mean velocity field. The aforementioned findings based on real-space probes provide valuable inputs for experimental measurements used for studying the spectrum of convective turbulence.

  9. Towards the proof of the cosmic censorship hypothesis

    Energy Technology Data Exchange (ETDEWEB)

    Krolak, Andrzej

    1986-05-01

    An attempt is made to formulate the cosmic censorship hypothesis put forward by Penrose (1969, Riv. Nuovo Cimento Ser. 1 Num. Spec. 1 252) as a theorem which could be subject to mathematical proof. It is proved that a weakly asymptotically simple and empty spacetime must be future asymptotically predictable if the energy and the strong causality conditions hold and either all singularities are of Tipler's strong curvature type and once singularity occurs there exists a marginally outgoing null geodesic or each singularity is preceded by the occurrence of a closed trapped surface. The marginally outgoing null geodesics may not be admitted by general naked singularities. However, it is shown that they occur if on the Cauchy horizon the global hyperbolicity in violated is such a way that causal simplicity does not hold. This means that a wide class of nakedly singular spacetimes is considered. This result gives some support to the validity of Penrose's hypothesis.

  10. Hyman Minsky's financial instability hypothesis and the Greek debt crisis

    Directory of Open Access Journals (Sweden)

    Sergey Beshenov

    2015-12-01

    Full Text Available This article attempts to analyze the current debt crisis in Greece based on the financial instability hypothesis developed by Hyman Minsky. This article shows that the hypothesis provides an understanding of how an economy endogenously becomes “financially fragile” and thus prone to crises. The authors analyze how public and private sector behavior in the Greek economy led to the country's debt crisis. In particular, based on a sample of 36 Greek companies, the authors show that between 2001 and 2014, the majority of those companies had switched to fragile financial structures. Special attention is devoted to the negative consequences of applying the neoclassical doctrine of “austerity measures” in Greece as the principal “anti-crisis” concept of mainstream economic science.

  11. Isotopic Resonance Hypothesis: Experimental Verification by Escherichia coli Growth Measurements

    Science.gov (United States)

    Xie, Xueshu; Zubarev, Roman A.

    2015-03-01

    Isotopic composition of reactants affects the rates of chemical and biochemical reactions. As a rule, enrichment of heavy stable isotopes leads to progressively slower reactions. But the recent isotopic resonance hypothesis suggests that the dependence of the reaction rate upon the enrichment degree is not monotonous. Instead, at some ``resonance'' isotopic compositions, the kinetics increases, while at ``off-resonance'' compositions the same reactions progress slower. To test the predictions of this hypothesis for the elements C, H, N and O, we designed a precise (standard error +/-0.05%) experiment that measures the parameters of bacterial growth in minimal media with varying isotopic composition. A number of predicted resonance conditions were tested, with significant enhancements in kinetics discovered at these conditions. The combined statistics extremely strongly supports the validity of the isotopic resonance phenomenon (p biotechnology, medicine, chemistry and other areas.

  12. Towards the proof of the cosmic censorship hypothesis

    International Nuclear Information System (INIS)

    Krolak, Andrzej

    1986-01-01

    An attempt is made to formulate the cosmic censorship hypothesis put forward by Penrose [1969, Riv. Nuovo Cimento Ser. 1 Num. Spec. 1 252] as a theorem which could be subject to mathematical proof. It is proved that a weakly asymptotically simple and empty spacetime must be future asymptotically predictable if the energy and the strong causality conditions hold and either all singularities are of Tipler's strong curvature type and once singularity occurs there exists a marginally outgoing null geodesic or each singularity is preceded by the occurrence of a closed trapped surface. The marginally outgoing null geodesics may not be admitted by general naked singularities. However, it is shown that they occur if on the Cauchy horizon the global hyperbolicity in violated is such a way that causal simplicity does not hold. This means that a wide class of nakedly singular spacetimes is considered. This result gives some support to the validity of Penrose's hypothesis. (author)

  13. Hypothesis testing in students: Sequences, stages, and instructional strategies

    Science.gov (United States)

    Moshman, David; Thompson, Pat A.

    Six sequences in the development of hypothesis-testing conceptions are proposed, involving (a) interpretation of the hypothesis; (b) the distinction between using theories and testing theories; (c) the consideration of multiple possibilities; (d) the relation of theory and data; (e) the nature of verification and falsification; and (f) the relation of truth and falsity. An alternative account is then provided involving three global stages: concrete operations, formal operations, and a postformal metaconstructivestage. Relative advantages and difficulties of the stage and sequence conceptualizations are discussed. Finally, three families of teaching strategy are distinguished, which emphasize, respectively: (a) social transmission of knowledge; (b) carefully sequenced empirical experience by the student; and (c) self-regulated cognitive activity of the student. It is argued on the basis of Piaget's theory that the last of these plays a crucial role in the construction of such logical reasoning strategies as those involved in testing hypotheses.

  14. Why is muscularity sexy? Tests of the fitness indicator hypothesis.

    Science.gov (United States)

    Frederick, David A; Haselton, Martie G

    2007-08-01

    Evolutionary scientists propose that exaggerated secondary sexual characteristics are cues of genes that increase offspring viability or reproductive success. In six studies the hypothesis that muscularity is one such cue is tested. As predicted, women rate muscular men as sexier, more physically dominant and volatile, and less committed to their mates than nonmuscular men. Consistent with the inverted-U hypothesis of masculine traits, men with moderate muscularity are rated most attractive. Consistent with past research on fitness cues, across two measures, women indicate that their most recent short-term sex partners were more muscular than their other sex partners (ds = .36, .47). Across three studies, when controlling for other characteristics (e.g., body fat), muscular men rate their bodies as sexier to women (partial rs = .49-.62) and report more lifetime sex partners (partial rs = .20-.27), short-term partners (partial rs = .25-.28), and more affairs with mated women (partial r = .28).

  15. Hypothesis driven development of new adjuvants: short peptides as immunomodulators.

    Science.gov (United States)

    Dong, Jessica C; Kobinger, Gary P

    2013-04-01

    To date, vaccinations have been one of the key strategies in the prevention and protection against infectious pathogens. Traditional vaccines have well-known limitations such as safety and efficacy issues, which consequently deems it inappropriate for particular populations and may not be an effective strategy against all pathogens. This evidence highlights the need to develop more efficacious vaccination regiments. Higher levels of protection can be achieved by the addition of immunostimulating adjuvants. Many adjuvants elicit strong, undefined inflammation, which produces increased immunogenicity but may also lead to undesirable effects. Hypothesis driven development of adjuvants is needed to achieve a more specific and directed immune response required for optimal and safe vaccine-induced immune protection. An example of such hypothesis driven development includes the use of short immunomodulating peptides as adjuvants. These peptides have the ability to influence the immune response and can be extrapolated for adjuvant use, but requires further investigation.

  16. On the epidemiology of influenza

    Directory of Open Access Journals (Sweden)

    Scragg Robert

    2008-02-01

    Full Text Available Abstract The epidemiology of influenza swarms with incongruities, incongruities exhaustively detailed by the late British epidemiologist, Edgar Hope-Simpson. He was the first to propose a parsimonious theory explaining why influenza is, as Gregg said, "seemingly unmindful of traditional infectious disease behavioral patterns." Recent discoveries indicate vitamin D upregulates the endogenous antibiotics of innate immunity and suggest that the incongruities explored by Hope-Simpson may be secondary to the epidemiology of vitamin D deficiency. We identify – and attempt to explain – nine influenza conundrums: (1 Why is influenza both seasonal and ubiquitous and where is the virus between epidemics? (2 Why are the epidemics so explosive? (3 Why do they end so abruptly? (4 What explains the frequent coincidental timing of epidemics in countries of similar latitude? (5 Why is the serial interval obscure? (6 Why is the secondary attack rate so low? (7 Why did epidemics in previous ages spread so rapidly, despite the lack of modern transport? (8 Why does experimental inoculation of seronegative humans fail to cause illness in all the volunteers? (9 Why has influenza mortality of the aged not declined as their vaccination rates increased? We review recent discoveries about vitamin D's effects on innate immunity, human studies attempting sick-to-well transmission, naturalistic reports of human transmission, studies of serial interval, secondary attack rates, and relevant animal studies. We hypothesize that two factors explain the nine conundrums: vitamin D's seasonal and population effects on innate immunity, and the presence of a subpopulation of "good infectors." If true, our revision of Edgar Hope-Simpson's theory has profound implications for the prevention of influenza.

  17. Global epidemiology of celiac disease

    Directory of Open Access Journals (Sweden)

    S. V. Bykova

    2018-01-01

    Full Text Available The review presents the data on the prevalence of celiac disease in various world regions. The numbers of patients with celiac disease continues to rise every year. According to some authors, this is to be related not only to improvement in diagnosis, but to other extrinsic factors, as well, that require additional studies. In the 1980s the prevalence of this disease was 1.05%, and by the beginning of 2000s, it amounted to 1.99%. In particular, from 1993 to 2002 in Britain its incidence increased from 6 to 13.3 per 100,000. Both raised awareness of doctors and conduction of epidemiological studies play a decisive role in the improvement of the diagnosis of celiac disease. The information cumulated up to now makes it possible to conclude that the highest diagnostic rates of celiac disease can be found in the risk groups. They include 1st and 2nd degree relatives of patients with celiac disease, patients with autoimmune disorders (type 1 diabetes mellitus, autoimmune thyroiditis; those with clinical signs of an intestinal disorder, such as chronic diarrhea, as well as patients with anemia, osteoporosis and high transaminase levels of unknown origin. According to the Finnish epidemiological study, the prevalence of celiac disease, depending on the risk group, may vary from 6.6 to 16.3%. The guidelines by the American College of Gastroenterology, British Society of Gastroenterology, North-American Society of Pediatric Gastroenterology, and the Russian Consensus on Diagnosis and Treatment of Celiac Disease in Adults and Children all recommend thorough examination of patients from the risk groups. Active diagnosis of celiac disease (screening has been recognized as one of the approaches to primary prevention to autoimmune disorders and cancer.

  18. The Literal Translation Hypothesis in ESP Teaching/Learning Environments

    Directory of Open Access Journals (Sweden)

    Pedro A. Fuertes-Olivera

    2015-11-01

    Full Text Available Research on the characteristics of specialized vocabulary usually replicates studies that deal with general words, e.g. they typically describe frequent terms and focus on their linguistic characteristics to aid in the learning and acquisition of the terms. We dispute this practise, as we believe that the basic characteristic of terms is that they are coined to restrict meaning, i.e. to be as precise and as specific as possible in a particular context. For instance, around 70% of English and Spanish accounting terms are multi-word terms, most of which contain more than three orthographic words that syntactically behave in a way that is very different from the syntactic behaviour of the node on which they are formed (Fuertes-Olivera and Tarp, forthcoming. This has prompted us to propose a research framework that investigates whether or not the literal translation hypothesis, which has been addressed in several areas of translation studies, can also be applied in ESP teaching/learning environments. If plausible, the assumptions on which this hypothesis is based can shed light on how learners disambiguate terms they encounter. Within this framework, this paper presents evidence that the literal translation hypothesis is possible in ESP; it offers the results of a pilot study that sheds light on how this hypothesis may work, and also discusses its usability in the context of ESP learning. In particular, this paper presents strategies for teaching multi-word terms that are different from those currently based on corpus data. We believe that exercises such as “cloze”, “fill in” and similar “guessing” exercises must be abandoned in ESP teaching/learning environments. Instead, we propose exercises that reproduce L1 teaching and learning activities, i.e., exercises that are typically used when acquiring specialised knowledge and skills in any domain, e.g. taking part in meetings and giving presentations in a business context.

  19. SU(7) GUT and evasion of the survival hypothesis

    International Nuclear Information System (INIS)

    Umemura, I.; Yamamoto, K.

    1981-01-01

    Characteristic features of an SU(7) GUT are discussed, in which the fundamental representation 7 consists of SU(5)'5 and its two singlets with charge q = +-1/2. The so-called survival hypothesis for fermions is naturally evaded by a kind of electric charge conservation due to q = +-1/2, and a brief comment on the suppression of the νsub(e) mass is given also. (orig.)

  20. Statefinder diagnostic for cosmology with the abnormally weighting energy hypothesis

    International Nuclear Information System (INIS)

    Liu Daojun; Liu Weizhong

    2008-01-01

    In this paper, we apply the statefinder diagnostic to the cosmology with the abnormally weighting energy hypothesis (AWE cosmology), in which dark energy in the observational (ordinary matter) frame results from the violation of the weak equivalence principle by pressureless matter. It is found that there exist closed loops in the statefinder plane, which is an interesting characteristic of the evolution trajectories of statefinder parameters and can be used to distinguish AWE cosmology from other cosmological models