Academic literature on the topic 'Barker hypothesis'
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Journal articles on the topic "Barker hypothesis"
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van Ginneken, Vincent, and Clemens Löwik. "“Extension of the “Fetal Origin Hypothesis of Barker” towards the “Fetal Origin Hypothesis of Mental Diseases”." Psychology and Mental Health Care 2, no. 3 (July 6, 2018): 01–07. http://dx.doi.org/10.31579/2637-8892/033.
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In this editorial we will first describe most common information about the intriguing “traditional” fetal origin hypothesis of Barker for physiological, endocrine and cardiovascular diseases (CVDs). The ‘developmental origins of adult disease’ hypothesis, often called the ‘Barker hypothesis’, states that adverse influences early in development, and particularly during intrauterine life, can result in permanent changes in physiology and metabolism, which result in increased disease risk in adulthood.
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Daniels, Stephen R. "The Barker hypothesis revisited." Journal of Pediatrics 151, no. 6 (December 2007): A3. http://dx.doi.org/10.1016/j.jpeds.2007.10.036.
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Daniels, Stephen R. "The Barker hypothesis revisited." Journal of Pediatrics 173 (June 2016): 1–3. http://dx.doi.org/10.1016/j.jpeds.2016.04.031.
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Wilson, John. "The Barker Hypothesis An Analysis." Australian and New Zealand Journal of Obstetrics and Gynaecology 39, no. 1 (February 1999): 1–7. http://dx.doi.org/10.1111/j.1479-828x.1999.tb03432.x.
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Wang, Yan Qiu, Hui Juan Zhang, and Martin J. Quinn. "Fetal Hypertension and the “Barker Hypothesis”." Angiology 71, no. 1 (August 29, 2019): 92–93. http://dx.doi.org/10.1177/0003319719870952.
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Young, Lorraine E. "Imprinting of Genes and the Barker Hypothesis." Twin Research 4, no. 5 (October 1, 2001): 307–17. http://dx.doi.org/10.1375/1369052012632.
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Lumbers, Eugenie R., Ze-Yan Yu, and Karen J. Gibson. "The Selfish Brain And The Barker Hypothesis." Clinical and Experimental Pharmacology and Physiology 28, no. 11 (November 2001): 942–47. http://dx.doi.org/10.1046/j.1440-1681.2001.03554.x.
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Gram, I. T., B. Straume, M. L. Lochen, B. K. Jacobsen, E. Arnesen, and E. Lund. "Earlier published work supports the "Barker hypothesis"." BMJ 310, no. 6992 (June 3, 1995): 1468. http://dx.doi.org/10.1136/bmj.310.6992.1468b.
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Young, Lorraine E. "Imprinting of Genes and the Barker Hypothesis." Twin Research 4, no. 5 (October 1, 2001): 307–17. http://dx.doi.org/10.1375/twin.4.5.307.
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AbstractSeveral common adult diseases appear to be related to impaired fetal growth and this may be caused either by nutritional inadequacies at particular stages of pregnancy or by variation in alleles at specific growth loci. Little is known about the genes involved in the underlying mechanism. This review proposes that at least some of the effects have their origins at imprinted loci, genes that are unusual because they are expressed from only one parental allele. Many imprinted genes are crucial for fetal growth and determine birthweight. They can be disrupted in the early embryo by environmental influences and these disruptions can be inherited through many cell cycles into adult tissues. Their disruption can affect specific organs during fetal development and disruption could affect adult disease in a variety of direct and indirect means. Imprinted genes may be particularly vulnerable to disruption as they are functionally haploid and their expression is regulated by different means from the rest of the genome. Thus many imprinted genes provide plausible candidates for programming adult disease and warrant further study in this context.
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Poulter, Neil R. "Birthweights, maternal cardiovascular events, and Barker hypothesis." Lancet 357, no. 9273 (June 2001): 1990–91. http://dx.doi.org/10.1016/s0140-6736(00)05131-x.
Full textDissertations / Theses on the topic "Barker hypothesis"
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Gravel, Jonathan. "Prenatal Exposure to Maternal Cigarette Smoke and Offspring Body Mass Index: A Prospective Study of Québec Children." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20247.
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Concern is mounting over the increase in prevalence and severity of overweight and obesity in children worldwide. Intrauterine life has been identified as a critical period for the development of overweight or obesity and other related chronic diseases. Prenatal exposure to maternal cigarette smoke (PEMCS) has consistently emerged as an important risk factor for excess weight in the offspring and is a targetable behaviour for prevention strategies.
This study examines first the relationship between PEMCS and overweight status of children at 10 years of age and second, whether PEMCS is associated with distinct longitudinal BMI trajectories. Analyses include multivariate and multinomial logistic regression and longitudinal group based modeling methods.
PEMCS was found to be a significant risk factor for overweight in children independent of birth weight and catch-up growth. However, PEMCS was not associated with BMI trajectory membership. Our results lend support to the paradigm of in-utero excess weight prevention.
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Kim, Seonghoon. "Essays in Economics of Social Security Disability Insurance and Health." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1365696633.
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Bambrick, Hilary Jane, and Hilary Bambrick@anu edu au. "Child growth and Type 2 Diabetes Mellitus in a Queensland Aboriginal Community." The Australian National University. Faculty of Arts, 2003. http://thesis.anu.edu.au./public/adt-ANU20050905.121211.
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Globally, the prevalence of Type 2 diabetes is rising. The most affected populations are those that have undergone recent and rapid transition towards a Western lifestyle, characterised by energy-dense diets and physical inactivity.¶
Two major hypotheses have attempted to explain the variation in diabetes prevalence, both between and within populations, beyond the contributions made by adult lifestyle. The thrifty genotype hypothesis proposes that some populations are genetically well adapted to surviving in a subsistence environment, and are predisposed to develop diabetes when the dietary environment changes to one that is fat and carbohydrate rich. The programming hypothesis focuses on the developmental environment, particularly on prenatal and early postnatal conditions: nutritional deprivation in utero and early postnatal life, measured by low birthweight and disrupted child growth, is proposed to alter metabolism permanently so that risk of diabetes is increased with subsequent exposure to an energy-dense diet. Both hypotheses emphasise discord between adaptation (genetic or developmental) and current environment, and both now put forward insulin resistance as a likely mechanism for predisposition.¶
Diabetes contributes significantly to morbidity and mortality among Australia’s Indigenous population. Indigenous babies are more likely to be low birthweight, and typical patterns of child growth include periods of faltering and rapid catch-up. Although there have been numerous studies in other populations, the programming hypothesis has not previously been tested in an Australian Indigenous community. The framework of the programming hypothesis is thus expanded to consider exposure of whole populations to adverse prenatal and postnatal environments, and the influence this may have on diabetes prevalence.¶
The present study took place in Cherbourg, a large Aboriginal community in southeast Queensland with a high prevalence of diabetes. Study participants were adults with diagnosed diabetes and a random sample of adults who had never been diagnosed with diabetes. Data were collected on five current risk factors for diabetes (general and central obesity, blood pressure, age and family history), in addition to fasting blood glucose levels. A lifestyle survey was also conducted. Participants’ medical records detailing weight growth from birth to five years were analysed with regard to adult diabetes risk to determine whether childhood weight and rate of weight gain were associated with subsequent diabetes. Adult lifestyle factors were
xiialso explored to determine whether variation in nutrition and physical activity was related to level of diabetes risk.¶
Approximately 20% of adults in Cherbourg have diagnosed diabetes. Prevalence may be as high as 38.5% in females and 42% in males if those who are high-risk (abnormal fasting glucose and three additional factors) are included. Among those over 40 years, total prevalence is estimated to be 51% for females and 59% for males.¶
Patterns of early childhood growth may contribute to risk of diabetes among adults. In particular, relatively rapid weight growth to five years is associated with both general and central obesity among adult women. This lends some qualified support to the programming hypothesis as catch-up growth has previously been incorporated into the model; however, although the most consistent association was found among those who gained weight more rapidly, it was also found that risk is increased among children who are heavier at any age.¶
No consistent associations were found between intrauterine growth retardation (as determined by lower than median birthweight and higher than median weight growth velocity to one and three months) and diabetes risk among women or men. A larger study sample with greater statistical power may have yielded less ambiguous results.¶
Among adults, levels of physical activity may be more important than nutritional intake in moderating diabetes risk, although features of diet, such as high intake of simple carbohydrates, may contribute to risk in the community overall, especially in the context of physical inactivity. A genetic component is not ruled out. Two additional areas which require further investigation include stress and high rates of infection, both of which are highly relevant to the study community, and may contribute to the insulin resistance syndrome.¶
Some accepted thresholds indicating increased diabetes risk may not be appropriate in this population. Given the relationship between waist circumference and other diabetes risk factors and the propensity for central fat deposition among women even with low body mass index (BMI), it is recommended that the threshold where BMI is considered a risk be lowered by 5kg/m2 for women, while no such recommendation is made for men.¶
There are a number of social barriers to better community health, including attitudes to exercise and obesity, patterns of alcohol and tobacco use and consumption of fresh foods. Some of these barriers are exacerbated by gender roles and expectations.¶
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Bambrick, Hilary. "Child growth and Type 2 Diabetes Mellitus in a Queensland Aboriginal Community." Phd thesis, 2003. http://hdl.handle.net/1885/46071.
Full textAbstract:
Globally, the prevalence of Type 2 diabetes is rising. The most affected populations are those that have undergone recent and rapid transition towards a Western lifestyle, characterised by energy-dense diets and physical inactivity. Two major hypotheses have attempted to explain the variation in diabetes prevalence, both between and within populations, beyond the contributions made by adult lifestyle. The thrifty genotype hypothesis proposes that some populations are genetically well adapted to surviving in a subsistence environment, and are predisposed to develop diabetes when the dietary environment changes to one that is fat and carbohydrate rich. The programming hypothesis focuses on the developmental environment, particularly on prenatal and early postnatal conditions: nutritional deprivation in utero and early postnatal life, measured by low birthweight and disrupted child growth, is proposed to alter metabolism permanently so that risk of diabetes is increased with subsequent exposure to an energy-dense diet. Both hypotheses emphasise discord between adaptation (genetic or developmental) and current environment, and both now put forward insulin resistance as a likely mechanism for predisposition.¶ Diabetes contributes significantly to morbidity and mortality among Australia’s Indigenous population. Indigenous babies are more likely to be low birthweight, and typical patterns of child growth include periods of faltering and rapid catch-up. Although there have been numerous studies in other populations, the programming hypothesis has not previously been tested in an Australian Indigenous community. The framework of the programming hypothesis is thus expanded to consider exposure of whole populations to adverse prenatal and postnatal environments, and the influence this may have on diabetes prevalence.¶ The present study took place in Cherbourg, a large Aboriginal community in southeast Queensland with a high prevalence of diabetes. Study participants were adults with diagnosed diabetes and a random sample of adults who had never been diagnosed with diabetes. Data were collected on five current risk factors for diabetes (general and central obesity, blood pressure, age and family history), in addition to fasting blood glucose levels. A lifestyle survey was also conducted. Participants’ medical records detailing weight growth from birth to five years were analysed with regard to adult diabetes risk to determine whether childhood weight and rate of weight gain were associated with subsequent diabetes. Adult lifestyle factors were also explored to determine whether variation in nutrition and physical activity was related to level of diabetes risk. ...
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Bamberg, Christian. "Die Barker-Hypothese unter dem Aspekt einer genetisch determinierten Plazentaperfusion /." 2005. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=013343789&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
Full textBooks on the topic "Barker hypothesis"
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Walsh, Bruce, and Michael Lynch. The Nonadaptive Forces of Evolution. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198830870.003.0004.
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This chapter examines the relative strengths of the nonadaptive evolutionary forces (drift, mutation, recombination) acting on genomes. It reviews estimators for effective population size, mutation rate, and recombination rate, and summarizes the known genomic results over a wide range of taxa. The mutation rate tends to be lower in organisms with larger effective population sizes, consistent with the drift-barrier hypothesis wherein selection is ineffective when it is less than the reciprocal of the effective population size.
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Takemoto, Hiroyuki, Yoshi Kawamoto, and Takeshi Furuichi. The formation of Congo River and the origin of bonobos: A new hypothesis. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198728511.003.0016.
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The Congo River functions as a strong geographical barrier for many terrestrial mammals in the Congo Basin, separating forest habitat into right and left banks of the river. However, there has been little discussion on the biogeography of the Congo Basin because the history of the river has been obscured. Based on the recent information of the sea-floor sediments near the mouth of the river and the geophysical survey on the continent, this chapter proposes a plausible hypothesis on the Congo River formation and presents a consequent hypothesis on the divergence of bonobos (Pan paniscus) from other Pan populations. The present hypothesis is also helpful for understanding the distribution of other primates and other mammals in the basin. Furthermore, this hypothesis suggests that all hominid clades, including human, chimpanzee and gorilla, except bonobo, evolved in the area north or east of the Congo River. La rivière du Congo a la fonction d’une barrière géographique forte pour plusieurs mammifères dans le bassin du Congo, séparant l’habitat forêt dans les banques gauches et droites de la rivière. Cependant, il y a eu peu de discussions sur la biogégraphie du bassin du Congo, parce que l’histoire de la rivière a été voilée. Récemment, quelque données importantes qui peuvent avoir des liens avec la formation de la rivière du Congo ont été acquise, surtout par la recherche des sédiments du fond marin près de la bouche de la rivière et par l’enquête géographique du continent. À partir de cette nouvelle information, nous avons proposé une hypothèse plausible sur la formation de la rivière du Congo. Nous avons aussi présenté une hypothèse conséquente sur la divergence des bonobos (Pan paniscus) des autres populations Pan (voire Takemoto et al., 2015 pour la publication originale de cette étude). L’hypothèse présente nous aide aussi à comprendre la distribution des autre primates et des autres mammifères dans le bassin. De plus, cette hypothèse suggère que tous les hominidés clades, humains inclus, chimpanzés et gorilla à l’exception du bonobo, ont évolué dans la régions du nord ou de l’est de la rivière du Congo.
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Poplack, Shana. Dealing with variability in loanword integration. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190256388.003.0005.
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This chapter tests a strong loanword integration hypothesis: that donor-language material that has been borrowed will display variability in morphosyntactic integration paralleling that of the recipient language. This requires explicitly marshalling the recipient language as the benchmark for comparison, an innovation implemented here for the first time. Illustrating with the typologically different Tamil-English language pair, word order and case-marking of English-origin objects of Tamil verbs are analyzed. English indirect objects are overwhelmingly inflected with Tamil dative markers, but direct objects tend not to be marked for the accusative. Comparison reveals that this patterning reflects the case-marking variability inherent in the recipient-language benchmark, compelling us to recognize even these apparently bare forms as borrowed, and supporting the Nonce Borrowing Hypothesis. This demonstrates that the facts of variability must be taken into account to identify which forms have been borrowed and which have been code-switched.
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Elewaut, Dirk, Heleen Cypers, Matthew L. Stoll, and Charles O. Elson. Extra-articular manifestations: inflammatory bowel disease. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198734444.003.0017.
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A significant overlap exists between spondyloarthritis (SpA) and inflammatory bowel disease (IBD), particularly in the IL-23/IL-17 pathway. Shared immunologic mechanisms include aberrant innate immune responses, an excess of Th1/Th17-mediated immunity, and inadequate immune regulation. Many genetic factors associated with IBD are involved in host–pathogen interactions and intestinal barrier function, and the intestinal microbiota do appear to play an important role in disease development. Hence the current hypothesis for IBD pathogenesis is that it stems from a dysregulated immune response to intestinal microbiota in a genetically susceptible host. In SpA, evidence for a role of intestinal microbiota is less abundant, but given the overlap with IBD, it is plausible that gut microbiota are important players in SpA pathogenesis as well. However, there are significant genetic differences between these two conditions, as well as differing responses to biologic therapy.
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Ziegeler, Debra. Are Constructions Dialect-Proof? Edited by Markku Filppula, Juhani Klemola, and Devyani Sharma. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199777716.013.31.
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The present chapter outlines the possible problems that may arise from applying a construction grammar approach to the study of international dialects of English. Using Singapore English as a base for comparison, it discusses construction types such as the progressive construction, the ‘false’ transitive construction, and the bare nominal construction (BNC), raising the question whether constructions in contact situations can be seen as constructions of the lexifier source language or the substrate languages which usually provide the syntactic source for the construction type. It also approaches the notion of ‘coercion’ often associated with construction analysis, and proposes that such a notion need not be evoked at all, given the hypothesis of ‘merger’ constructions, which in many cases can justify the selection of an ambiguous syntactic form across dialects by accommodating two (allo-construction) variants of the same construction type.
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Batmanian, Natalie, and Karin Stromswold. Getting to the Root of the Matter. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190464783.003.0008.
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Spontaneous speech data from three monolingual Turkish-speaking children between the ages 2;1 and 2;8 revealed that children produce bare lexical stems in ungrammatical contexts before they use grammatical morphemes productively. Given that root words are very rare in Turkish, the fact that Turkish children produce them indicates that they are able to decompose multimorphemic words into root + grammatical affixes. We also tested the hypothesis that when the correspondence between morphological form and grammatical meaning is one-to-one, morphemes are likely to be acquired earlier than when the correspondence between form and meaning is one-to-many (Slobin, 1973). Three grammatical morphemes, despite appearing equally frequently in adult speech, were acquired at different stages by children. The past tense inflection –di, which has a one-to-one correspondence between morphological form and grammatical meaning, is the morpheme that was acquired first by the children.
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Thornes, Tim. On the heterogeneity of Northern Paiute directives. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198803225.003.0007.
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The formal encoding of directive speech in Northern Paiute (W. Numic, Uto-Aztecan) is quite heterogeneous, despite the simplicity of bare verb stem, addressee-directed command forms. The language employs a range of grammatical constructions both to colour the force of a canonical imperative and to form non-canonical imperatives. This chapter addresses formal strategies that express directive speech in Northern Paiute with attention to pragmatic context in naturally occurring speech, in addition to preliminary comparisons with related languages and hypotheses around historical developments in Numic and beyond, placing the data in the context of a general typology of commands in the world’s languages. The use of aspect marking, deontic modality, and subordinating morphology is common. The ways in which aspectual morphology is deployed in Northern Paiute directives do not always follow patterns found in other languages. Of further interest is the evidence for a biclausal origin in the grammar of directive speech acts.
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Lewis, Myles, and Tim Vyse. Genetics of connective tissue diseases. Oxford University Press, 2013. http://dx.doi.org/10.1093/med/9780199642489.003.0042.
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The advent of genome-wide association studies (GWAS) has been an exciting breakthrough in our understanding of the genetic aetiology of autoimmune diseases. Substantial overlap has been found in susceptibility genes across multiple diseases, from connective tissue diseases and rheumatoid arthritis (RA) to inflammatory bowel disease, coeliac disease, and psoriasis. Major technological advances now permit genotyping of millions of single nucleotide polymorphisms (SNPs). Group analysis of SNPs by haplotypes, aided by completion of the Hapmap project, has improved our ability to pinpoint causal genetic variants. International collaboration to pool large-scale cohorts of patients has enabled GWAS in systemic lupus erythematosus (SLE), systemic sclerosis and Behçet's disease, with studies in progress for ANCA-associated vasculitis. These 'hypothesis-free' studies have revealed many novel disease-associated genes. In both SLE and systemic sclerosis, identified genes map to known pathways including antigen presentation (MHC, TNFSF4), autoreactivity of B and T lymphocytes (BLK, BANK1), type I interferon production (STAT4, IRF5) and the NFκB pathway (TNIP1). In SLE alone, additional genes appear to be involved in dysregulated apoptotic cell clearance (ITGAM, TREX1, C1q, C4) and recognition of immune complexes (FCGR2A, FCGR3B). Future developments include whole-genome sequencing to identify rare variants, and efforts to understand functional consequences of susceptibility genes. Putative environmental triggers for connective tissue diseases include infectious agents, especially Epstein-Barr virus; cigarette smoking; occupational exposure to toxins including silica; and low vitamin D, due to its immunomodulatory effects. Despite numerous studies looking at toxin exposure and connective tissue diseases, conclusive evidence is lacking, due to either rarity of exposure or rarity of disease.
Book chapters on the topic "Barker hypothesis"
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Edwards, Matthew. "The Barker Hypothesis." In Handbook of Famine, Starvation, and Nutrient Deprivation, 1–21. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-40007-5_71-1.
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Edwards, Matthew. "The Barker Hypothesis." In Handbook of Famine, Starvation, and Nutrient Deprivation, 191–211. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-319-55387-0_71.
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Liu, Xingrong, and Cuiping Chen. "Free Drug Hypothesis for CNS Drug Candidates." In Blood-Brain Barrier in Drug Discovery, 42–65. Hoboken, NJ: John Wiley & Sons, Inc, 2015. http://dx.doi.org/10.1002/9781118788523.ch3.
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Carvalho, Liliana Matias de, and Sofia N. Wasterlain. "Stresse infantil, morbilidade e mortalidade no sítio arqueológico do Neolítico Final/Calcolítico (4ª e 3º milénio a.C) do Monte do Carrascal 2 (Ferreira do Alentejo, Beja)." In Arqueologia em Portugal 2020 - Estado da Questão - Textos, 873–84. Associação dos Arqueólogos Portugueses e CITCEM, 2020. http://dx.doi.org/10.21747/978-989-8970-25-1/arqa63.
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Children go through various stages of development and growth. The Barker and Osmond “Developmental Origins of Health and Disease” hypothesis states that the stress episodes suffered in intrauterine/early childhood life have negative consequences in adulthood (propensity to diseases and anticipation of the age of death). In order to estimate the frequency of childhood stress in a sample of the Late Neolithic/Chalcolithic and understand its impact on the adult life of individuals, a sample of Monte do Carrascal 2 (Ferreira do Alentejo, Beja) was analysed following the methodology of Reid and Dean (2000, 2006). The individuals in the sample do not present many signs of childhood stress, suggesting a special care taken upon the younger members of the community.
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M. Baloyi, Shisana, and Kebogile Mokwena. "Metabolic Syndrome in Reproductive Health: Urgent Call for Screening." In Lifestyle and Epidemiology - Poverty and Cardiovascular Diseases a Double Burden in African Populations [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95971.
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Metabolic syndrome (MetSy) is a compilation of interrelated pathologic conditions characterized by central obesity, hypertension, insulin resistance and atherogenic dyslipidaemia. The prevalence of MetSy is rising globally. There is growing evidence which linked the individual components of MetSy to the increasing prevalence of poor reproductive health in both the male and female community. This text reviews the recent evidence associating MetSy to poor reproductive health as well as the underlying pathophysiology. The aims to study the relationship between MetSy and reproductive health. The effects of MetSy on fertility were examined and supporting evidence explaining the pathophysiology of dysfunction with each MetSy component extracted from the following medical databases, including CINAHL, MED- LINE, EMBASE, PubMed, and ERIC were described. Noncommunicable disease is rising at an alarming rate globally. Metabolic disorders like hyperlipidaemia, obesity, and insulin resistance can directly or indirectly affect the reproductive health and fertility in both men and women through the interruption of hypothalamic – pituitary – gonadal axis functions. Metabolic syndrome’s adverse effects are likely transgenerational (Barker hypothesis), where children born to obese mothers are at increased risk for obesity, diabetes and cardiovascular disease later in life. Therefore MetSy deserves attention and screening should be upscaled at all contacts for all age group of patients to save the future generations.
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Weich, Scott, and Martin Prince. "Cohort studies." In Practical Psychiatric Epidemiology, 155–76. Oxford University Press, 2003. http://dx.doi.org/10.1093/med/9780198515517.003.0009.
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A cohort study is one in which the outcome (usually disease status) is ascertained for groups of individuals defined on the basis of their exposure. At the time exposure status is determined, all must be free of the disease. All eligible participants are then followed up over time. Since exposure status is determined before the occurrence of the outcome, a cohort study can clarify the temporal sequence between exposure and outcome, with minimal information bias. The historical and the population cohort study (Box 9.1) are efficient variants of the classical cohort study described above, which nevertheless retain the essential components of the cohort study design. The exposure can be dichotomous [i.e. exposed (to obstetric complications at birth) vs. not exposed], or graded as degrees of exposure (e.g. no recent life events, one to two life events, three or more life events). The use of grades of exposure strengthens the results of a cohort study by supporting or refuting the hypothesis that the incidence of the disease increases with increasing exposure to the risk factor; a so-called dose–response relationship. The essential features of a cohort study are: ♦ participants are defined by their exposure status rather than by outcome (as in case–control design); ♦ it is a longitudinal design: exposure status must be ascertained before outcome is known. The classical cohort study In a classical cohort study participants are selected for study on the basis of a single exposure of interest. This might be exposure to a relatively rare occupational exposure, such as ionizing radiation (through working in the nuclear power industry). Care must be taken in selecting the unexposed cohort; perhaps those working in similar industries, but without any exposure to radiation. The outcome in this case might be leukaemia. All those in the exposed and unexposed cohorts would need to be free of leukaemia (hence ‘at risk’) on recruitment into the study. The two cohorts would then be followed up for (say) 10 years and rates at which they develop leukaemia compared directly. Classical cohort studies are rare in psychiatric epidemiology. This may be in part because this type of study is especially suited to occupational exposures, which have previously been relatively little studied as causes of mental illness. However, this may change as the high prevalence of mental disorders in the workplace and their negative impact upon productivity are increasingly recognized. The UK Gulf War Study could be taken as one rather unusual example of the genre (Unwin et al. 1999). Health outcomes, including mental health status, were compared between those who were deployed in the Persian Gulf War in 1990–91, those who were later deployed in Bosnia, and an ‘era control group’ who were serving at the time of the Gulf war but were not deployed. There are two main variations on this classical cohort study design: they are popular as they can, depending on circumstances, be more efficient than the classical cohort design. The population cohort study In the classical cohort study, participants are selected on the basis of exposure, and the hypothesis relates to the effect of this single exposure on a health outcome. However, a large cohort or panel of subjects are sometimes recruited and followed up, often over many years, to study multiple exposures and outcomes. No separate comparison group is required as the comparison group is generally an unexposed sub-group of the panel. Examples include the British Doctor's Study in which over 30,000 British doctors were followed up for over 20 years to study the effects of smoking and other exposures on health (Doll et al. 1994), and the Framingham Heart Study, in which residents of a town in Massachusetts, USA have been followed up for 50 years to study risk factors for coronary heart disease (Wolf et al. 1988). The Whitehall and Whitehall II studies in the UK (Fuhrer et al. 1999; Stansfeld et al. 2002) were based again on an occupationally defined cohort, and have led to important findings concerning workplace conditions and both physical and psychiatric morbidity. Birth cohort studies, in which everyone born within a certain chronological interval are recruited, are another example of this type of study. In birth cohorts, participants are commonly followed up at intervals of 5–10 years. Many recent panel studies in the UK and elsewhere have been funded on condition that investigators archive the data for public access, in order that the dataset might be more fully exploited by the wider academic community. Population cohort studies can test multiple hypotheses, and are far more common than any other type of cohort study. The scope of the study can readily be extended to include mental health outcomes. Thus, both the British Doctor's Study (Doll et al. 2000) and the Framingham Heart Study (Seshadri et al. 2002) have gone on to report on aetiological factors for dementia and Alzheimer's Disease as the cohorts passed into the age groups most at risk for these disorders. A variant of the population cohort study is one in which those who are prevalent cases of the outcome of interest at baseline are also followed up effectively as a separate cohort in order (a) to study the natural history of the disorder by estimating its maintenance (or recovery) rate, and (b) studying risk factors for maintenance (non-recovery) over the follow-up period (Prince et al. 1998). Historical cohort studies In the classical cohort study outcome is ascertained prospectively. Thus, new cases are ascertained over a follow-up period, after the exposure status has been determined. However, it is possible to ascertain both outcome and exposure retrospectively. This variant is referred to as a historical cohort study (Fig. 9.1). A good example is the work of David Barker in testing his low birth weight hypothesis (Barker et al. 1990; Hales et al. 1991). Barker hypothesized that risk for midlife vascular and endocrine disorders would be determined to some extent by the ‘programming’ of the hypothalamo-pituitary axis through foetal growth in utero. Thus ‘small for dates’ babies would have higher blood pressure levels in adult life, and greater risk for type II diabetes (through insulin resistance). A prospective cohort study would have recruited participants at birth, when exposure (birth weight) would be recorded. They would then be followed up over four or five decades to examine the effect of birth weight on the development of hypertension and type II diabetes. Barker took the more elegant (and feasible) approach of identifying hospitals in the UK where several decades previously birth records were meticulously recorded. He then traced the babies as adults (where they still lived in the same area) and measured directly their status with respect to outcome. The ‘prospective’ element of such studies is that exposure was recorded well before outcome even though both were ascertained retrospectively with respect to the timing of the study. The historical cohort study has also proved useful in psychiatric epidemiology where it has been used in particular to test the neurodevelopmental hypothesis for schizophrenia (Jones et al. 1994; Isohanni et al. 2001). Jones et al. studied associations between adult-onset schizophrenia and childhood sociodemographic, neurodevelopmental, cognitive, and behavioural factors in the UK 1946 birth cohort; 5362 people born in the week 3–9 March 1946, and followed up intermittently since then. Subsequent onsets of schizophrenia were identified in three ways: (a) routine data: cohort members were linked to the register of the Mental Health Enquiry for England in which mental health service contacts between 1974 and 1986 were recorded; (b) cohort data: hospital and GP contacts (and the reasons for these contacts) were routinely reported at the intermittent resurveys of the cohort; (c) all cohort participants identified as possible cases of schizophrenia were given a detailed clinical interview (Present State examination) at age 36. Milestones of motor development were reached later in cases than in non-cases, particularly walking. Cases also had more speech problems than had noncases. Low educational test scores at ages 8,11, and 15 years were a risk factor. A preference for solitary play at ages 4 and 6 years predicted schizophrenia. A health visitor's rating of the mother as having below average mothering skills and understanding of her child at age 4 years was a predictor of schizophrenia in that child. Jones concluded ‘differences between children destined to develop schizophrenia as adults and the general population were found across a range of developmental domains. As with some other adult illnesses, the origins of schizophrenia may be found in early life’. Jones' findings were largely confirmed in a very similar historical cohort study in Finland (Isohanni et al. 2001); a 31 year follow-up of the 1966 North Finland birth cohort (n = 12,058). Onsets of schizophrenia were ascertained from a national hospital discharge register. The ages at learning to stand, walk and become potty-trained were each related to subsequent incidence of schizophrenia and other psychoses. Earlier milestones reduced, and later milestones increased, the risk in a linear manner. These developmental effects were not seen for non-psychotic outcomes. The findings support hypotheses regarding psychosis as having a developmental dimension with precursors apparent in early life. There are many conveniences to this approach for the contemporary investigator. ♦ The exposure data has already been collected for you. ♦ The follow-up period has already elapsed. ♦ The design maintains the essential feature of the cohort study, namely that information bias with respect to the assessment of the exposure should not be a problem. ♦ As with the Barker hypothesis example, historical cohort studies are particularly useful for investigating associations across the life course, when there is a long latency between hypothesized exposure and outcome. Despite these important advantages, such retrospective studies are often limited by reliance on historical data that was collected routinely for other purposes; often these data will be inaccurate or incomplete. Also information about possible confounders, such as smoking or diet, may be inadequate.
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Norouzi, Nima. "Water Utilization Rate." In Practice, Progress, and Proficiency in Sustainability, 204–24. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-5109-0.ch010.
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In economic growth models, less attention is paid to natural resources and their importance on economic growth. The decline of the world's water resources, especially in countries with inherently limited water resources, such as Iran, has caused a water supply and demand crisis. This chapter deals with the effect of water utilization rate on economic growth. The hypothesis of this research is based on Barrow and Sala's Martin model developed by Barber. According to this model, the effect of the water utilization rate on economic growth can be nonlinear. The tool for measuring the amount of water in this study is the water utilization rate. Other explanatory variables used in the model include the share of water exports, the share of water activities, and the share of gross capital. This chapter uses a self-regression model with distributive interruption with the shore test approach for 1990-2020 for Iran. The estimation results indicate that the relationship between water utilization rate and economic growth for Iran is inversely U-shaped.
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Lewis, Theodore J. "The Origin of Yahweh." In The Origin and Character of God, 209–86. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780190072544.003.0006.
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Chapter Six examines the historical origin of Yahweh, the dominant deity of Israelite religion. Readers can evaluate the Hebrew Bible’s foundation stories about Yahweh (and vis-à-vis El worship) juxtaposed next to the epigraphic record with datable texts ranging from 14th-13th centuries BCE Egyptian geographical lists to a ninth century BCE Moabite inscription to multiple ninth-eighth centuries BCE Yahwistic inscriptions from a remote site on the Darb el-Ghazza caravan route just south of Qadesh-Barnea, a site with a long biblical pedigree. Additional topics include the meaning of the name Yahweh and its attestations in extra-biblical sources as well as the geographic origin of the deity. The latter includes a review of the Midianite-Kenite hypothesis studied alongside archaic Hebrew poetry (biblical and epigraphic) describing militaristic wilderness theophanies. Methodologically, the chapter also describes the Canaanite cultural continuum from the Middle Bronze Age through the Late Bronze Age and the Iron Age.
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Montanari, Alessandro, Maurizio Mainiero, Piero Farabollini, and Gaia Pignocchi. "Sedimentological and archaeological evidence for a Late Antique Little Ice Age climate event (536–660 CE) as recorded in a fluvial strath terrace of the Esino River (Marche region, Italy)." In From the Guajira Desert to the Apennines, and from Mediterranean Microplates to the Mexican Killer Asteroid: Honoring the Career of Walter Alvarez. Geological Society of America, 2022. http://dx.doi.org/10.1130/2022.2557(27).
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ABSTRACT Stratigraphic analysis of two sections of a fluvial strath terrace exposed on the left bank of the Esino River near the village of Trocchetti (province of Ancona, Marche region of central Italy), and the study of a large landslide located near the village of San Cristoforo, a few kilometers down valley from the Trocchetti fluvial terrace, provide evidence for two catastrophic environmental events, namely: (1) the aggradation on the riverbed of coarse, chaotic gravel due to a violent flashflood; and (2) the formation of a large ephemeral lake as the consequence of the landslide that barred the river channel at San Cristoforo. Archaeological and historical information about the lost Roman city of Tuficum, which was located just a kilometer upriver from the Trocchetti terrace, and ceramic artifacts found in the chaotic gravel unit, led us to the hypothesis that both the flashflood and the landslide were induced by the sudden, severe climate change of the Late Antique Little Ice Age (mid-sixth century to mid-seventh century CE).
Conference papers on the topic "Barker hypothesis"
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Assari, Soroush, Kaveh Laksari, Mary Barbe, and Kurosh Darvish. "Cerebral Blood Pressure Rise During Blast Exposure in a Rat Model of Blast-Induced Traumatic Brain Injury." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64992.
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Blast-induced traumatic brain injury (bTBI) has been called the signature wound of war in the past decade. The mechanisms of such injuries are not yet completely understood. One of the proposed hypotheses is the transfer of pressure wave from large torso blood vessels to the cerebrovasculature as a major contributing factor to bTBI. The aim of this study was to investigate this hypothesis by measuring cerebral blood pressure rise during blast exposure and comparing two scenarios of head-only or chest-only exposures to the blast wave. The results showed that the cerebral blood pressure rise was significantly higher in chest-only exposure, and caused infiltration of blood-borne macrophages into the brain. It is concluded that a significantly high pressure wave transfers from torso to cerebrovasculature during exposure of the chest to a blast wave. This wave may lead to blood-brain barrier disruption and consequently trigger secondary neuronal damage.
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Postnov, Dmitry E., Eugeny B. Postnikov, Anatoly S. Karavaev, and Oxana V. Glushkovskaya-Semyachkina. "On trans-parenchymal transport after blood brain barrier opening: pump-diffuse-pump hypothesis." In Saratov Fall Meeting 2017: Fifth International Symposium on Optics and Biophotonics: Laser Physics and Photonics XIX; Computational Biophysics and Analysis of Biomedical Data IV, edited by Vladimir L. Derbov and Dmitry E. Postnov. SPIE, 2018. http://dx.doi.org/10.1117/12.2315196.
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Ashpis, David E., and Matthew C. Laun. "Dielectric Barrier Discharge (DBD) Plasma Actuators Thrust - Measurement Methodology Incorporating New Anti-Thrust Hypothesis." In 52nd Aerospace Sciences Meeting. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2014. http://dx.doi.org/10.2514/6.2014-0486.
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Grassi, Ana Giulia F., Rodrigo S. Lavieri, Adriano A. P. Pereira, and Eduardo A. Tannuri. "CFD and Experimental Analysis of Current Forces of Pusher-Barge Systems." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-10404.
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The water transportation of cargo is, among several possible modes of transportation, the most economically and environmentally efficient. Adding technology to pusher-barge systems increases the efficiency of this form of transport. It is not only limited to the design and manufacturing process, but extends to the training of commanders and crews. An efficient way to ensure this training is immersion in virtual scenarios that simulate reality. To have realistic response of the simulator to external commands and boundary conditions, it is necessary to understand the hydrodynamics of the pusher-barge system in its various working conditions. This paper presents results and discussions on the hydrodynamics of a river pusher-barge system based on computational results from CFD (Computational Fluid Dynamics) and experimental results from towing tank test using small scale model. Initially the coefficients of current forces acting on the vessel in the horizontal plane (surge, sway and yaw) obtained by the two methods are presented. Several current incident angles were analyzed in the following cases: two drafts (ballasted and full-loaded), three configurations of barges (1 × 1, 2 × 1 and 2 × 2) and two water depths. Next, the results are compared and the divergences due to small difference in geometry and scale effects are analyzed. The hypotheses formulated for possible causes of the divergences are grounded through mathematical and experimental models and simulations. To cancel these effects and perform validation of CFD, new simulations are presented with similar geometry to the model tested.
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Galkina, Ekaterina. "Psychological barriers of the initial stage of professional activity of the self–employed." In Safety psychology and psychological safety: problems of interaction between theorists and practitioners. «Publishing company «World of science», LLC, 2020. http://dx.doi.org/10.15862/53mnnpk20-20.
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The problem of the study is that it is not sufficiently studied what psychological barriers people face at the initial stage of professional activity as self-employed. The aim of the study is to study the features of psychological barriers at the initial stage of professional activity of self-employed people. Research hypothesis: at the initial stage of professional activity as self-employed people face psychological barriers in the organizational and creative areas of entrepreneurial activity. The problem of psychological barriers was considered in their works by S. Rubinstein, N. Podymov, I. Pavlov, R. Shakurov and others. The article formulates particular definitions of the main concepts. Methodology: analysis of an individual case using interviews with processing in the framework of interpretive phenomenology. Respondent: female, 34 years old, self-employed as a psychologist for 1 year. Results: psychological barrier of accepting financial responsibility, barrier of adherence to a certain professional culture, barrier of competence in the profession. Certain psychological barriers can arise in connection with certain underlying medical conditions. The conclusions are that psychological barriers are a complex mental education, can be overcome in stages, and motivation of the subject is important for overcoming barriers.
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Lin, Kathleen, and Madhavan L. Raghavan. "Study of Folding in Endovascular Grafts due to Oversizing." In ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19413.
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Endovascular grafts (EVG) are stent grafts implanted percutaneously to repair aortic aneurysms. The primary source of fixation of the EVG is the friction from radial forces generated by graft over-sizing. Although a 10–20% over-sizing is common, it may range from 0 to 45% [1]. A clinical study on patient outcomes noted high migration rates when oversizing was greater than 30%. A recent in vitro study of barbed EVGs by our group found that greater than 30% oversizing results in decreased fixation strength quantified by the force needed to pullout the graft from the aorta [2]. In that study, based on anecdotal visual observation, we hypothesized that grafts with excessive oversizing may be folding, resulting in poor fixation strength. In this study, we ranked the level of folding noted in EVGs with varying oversizing in order to test that hypothesis.
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Di Miceli, Enrica, Vincenzo Bianco, Giorgio Monti, and Maria Grazia Filetici. "A RECONSTRUCTION HYPOTHESIS OF COLLAPSED ARCHAEOLOGICAL MASONRY BARREL VAULTS EMPLOYING FRICTIONAL BEARINGS, WITH APPLICATION TO THE CASE STUDY OF THE GALLERIA DELLE VOLTE CROLLATE, IN ROME." In 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering Methods in Structural Dynamics and Earthquake Engineering. Athens: Institute of Structural Analysis and Antiseismic Research School of Civil Engineering National Technical University of Athens (NTUA) Greece, 2017. http://dx.doi.org/10.7712/120117.5591.18271.
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Raad, Bahram, Narges Shayesteh Moghaddam, and Mohammad Elahinia. "A Comparison Between Porous NiTi and Ti-6Al-4V Fixation Hardware on Bone Remodeling After a Reconstruction Surgery." In ASME 2016 11th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/msec2016-8556.
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The aim of this article is to investigate the effect of two different fixation hardware materials on bone remodeling after a mandibular reconstruction surgery and to restore the mandible’s function, healthy appearance, mastication, swallowing, breathing, and speech. The hypothesis is that using fixation hardware with stiffness close to that of the surrounding bone will result in a more successful healing process in the mandible bone. The finite element model includes the material properties and forces of the cancellous bone, cortical bone, ligaments, muscles, and teeth. The reconstruction surgery is modeled by including the fixation hardware and the grafted bone. In the sectioned mandible, to best mimic the geometry of the mandible, two single barrel grafts are placed at the top of each other to form a double barrel graft set. Two different materials were used as the mandibular fixation parts, stiff Ti-6Al-4V, and porous superelastic Nickel-Titanium (NiTi) alloys. A comparison of these two alloys demonstrates that using porous NiTi alloy as the fixation part results in a faster healing pace. Furthermore, the density distribution in the mandibular bone after the healing process is more similar to the normal mandible density distribution. The simulations results indicate that the porous superelastic NiTi fixation hardware transfers and distributes the existing forces on the mandible bone more favorably. The probability of stress shielding and/or stress concentration decrease. This type of fixation hardware, therefore, is more appropriate for mandible bone reconstruction surgery.
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Wolniak, Radoslaw. "THE PERCEPTION OF ARCHITECTURAL BARRIERS IN SOSNOWIEC MUNICIPIAL OFFICE FROM DISABLE PERSON POINT OF VIEW." In GEOLINKS International Conference. SAIMA Consult Ltd, 2020. http://dx.doi.org/10.32008/geolinks2020/b2/v2/37.
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The paper concentrate on problems connected with problems of peoples with disability. The main aims of the paper is to measure the level of quality of service in the case of architectural barriers in municipal offices by peoples in disability. We made following hypothesis: the types of disability significantly affects the perception of quality of services in municipal office regarding architectural barrier. The problem of satisfaction of people with disability in the case of architectural barriers in municipal office in Sosnowiec was analyzed from type of disability point of view. We distinguished five main types of disability in the paper: sensory impairment – a lack, damage or disorder of sensory analysers’ function (this category includes the blind, the visually impaired, the deaf, hard of hearing persons and people with visual and auditory perception disorders); intellectual impairment – mental retardation; social functioning impairment – disorders of neural and emotional balance; communication impairment – hindered verbal contact (speech impediments, autism, stammering); motor impairment – people with motor organ dysfunction. On the basis of that are discussed in this publication the research, we can conclude that the overall assessment of architectural barriers for people with disabilities is as in the case of the Municipal Office in Sosnowiec at an average level. The problems focus mainly on matters of specialized service selected groups of customers with disabilities who require further elaboration. Another type of problem is to issue a limited number of parking spaces for the disabled, but for objective reasons, it will be difficult to solve. Also we can say that the assessment of the architectural barriers by peoples with various types of disability vary significantly. The architectural barriers are the problem especially for people with motor disabilities – those persons are going to municipal office often and because of type of their disability barriers within the office and near the office is the big problem for them. The results are supporting the hypothesis that the type of disability affects perception of architectural barriers by peoples with disabilities.
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Schaudt, Kenneth J., Christopher Wajnikonis, Don Spencer, Jie Xu, Steve Leverette, and Rodney Masters. "Benchmarking of VIV Suppression Systems." In ASME 2008 27th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/omae2008-57065.
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A new form of Vortex-Induced Vibration (VIV) suppression device, the AIMS Dual-fin Flow Splitter (ADFS), has been developed, tested and benchmarked against bare-pipe, 5d and 15d pitch strakes and conventional teardrop fairings. Testing included high-mode number in-situ tests as well as low Reynolds number (<300,000) and high Reynolds number (<1.9 million) forced and free tank tests. Finally, wind tunnel tests and in-water Particle Image Velocimetry (PIV) were used to test the hypothesis that the dual-fin flow splitter replaces the oscillating wake of a blunt body with a stable, attached circulation behind the body and between the fins. Such a replacement was hypothesized to result in reduced drag, and the elimination of almost all VIV. The paper will describe the testing program and results, and present the incorporation of the test results into riser models.
Reports on the topic "Barker hypothesis"
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Jander, Georg, and Daniel Chamovitz. Investigation of growth regulation by maize benzoxazinoid breakdown products. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600031.bard.
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Introduction Previous research had suggested that benzoxazinoids, a class of defensive metabolites found in maize, wheat, rye, and wild barley, are not only direct insect deterrents, but also influence other areas of plant metabolism. In particular, the benzoxazinoid 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxa- zin-3(4H)- one (DIMBOA) was implicated in: (i) altering plant growth by interfering with auxin signaling, and (ii) leading to the induction of gene expression changes and secondary plant defense responses. The overall goal of this proposal was to identify mechanisms by which benzoxazinoids influence other aspects of plant growth and defense. Specifically, the following hypotheses were proposed to be tested as part of an approved BARD proposal: Benzoxazinoid breakdown products directly interfere with auxin perception Global changes in maize and barley gene expression are induced by benzoxazinoid activation. There is natural variation in the maize photomorphogenic response to benzoxazinoids. Although the initial proposal included experiments with both maize and barley, there were some technical difficulties with the proposed transgenic barley experiments and most of the experimental results were generated with maize. Summary of major findings Previous research by other labs, involving both maize and other plant species, had suggested that DIMBOA alters plant growth by interfering with auxin signaling. However, experiments conducted in both the Chamovitz and the Jander labs using Arabidopsis and maize, respectively, were unable to confirm previously published reports of exogenously added DIMBOA effects on auxin signaling. Nevertheless, analysis of bx1 and bx2 maize mutant lines, which have almost no detectable benzoxazinoids, showed altered responses to blue light signaling. Transcriptomic analysis of maize mutant lines, variation in inbred lines, and responses to exogenously added DIMBOA showed alteration in the transcription of a blue light receptor, which is required for plant growth responses. This finding provides a novel mechanistic explanation of the trade-off between growth and defense that is often observed in plants. Experiments by the Jander lab and others had demonstrated that DIMBOA not only has direct toxicity against insect pests and microbial pathogens, but also induces the formation of callose in both maize and wheat. In the current project, non-targeted metabolomic assays of wildtype maize and mutants with defects in benzoxazinoid biosynthesis were used to identify unrelated metabolites that are regulated in a benzoxazinoid-dependent manner. Further investigation identified a subset of these DIMBOA-responsive compounds as catechol, as well as its glycosylated and acetylated derivatives. Analysis of co-expression data identified indole-3-glycerol phosphate synthase (IGPS) as a possible regulator of benzoxazinoid biosynthesis in maize. In the current project, enzymatic activity of three predicted maize IGPS genes was confirmed by heterologous expression. Transposon knockout mutations confirmed the function of the maize genes in benzoxazinoid biosynthesis. Sub-cellular localization studies showed that the three maize IGPS proteins are co-localized in the plastids, together with BX1 and BX2, two previously known enzymes of the benzoxazinoid biosynthesis pathway. Implications Benzoxazinoids are among the most abundant and effective defensive metabolites in maize, wheat, and rye. Although there is considerable with-in species variation in benzoxazinoid content, very little is known about the regulation of this variation and the specific effects on plant growth and defense. The results of this research provide further insight into the complex functions of maize benzoxazinoids, which are not only toxic to pests and pathogens, but also regulate plant growth and other defense responses. Knowledge gained through the current project will make it possible to engineer benzoxazinoid biosynthesis in a more targeted manner to produce pest-tolerant crops without negative effects on growth and yield.
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Evans, Donald L., Avigdor Eldar, Liliana Jaso-Friedmann, and Herve Bercovier. Streptococcus Iniae Infection in Trout and Tilapia: Host-Pathogen Interactions, the Immune Response Towards the Pathogen and Vaccine Formulation. United States Department of Agriculture, February 2005. http://dx.doi.org/10.32747/2005.7586538.bard.
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The objectives of the BARD proposal were to determine the mechanisms of nonspecific cytotoxic cells (NCC) that are necessary to provide heightened innate resistance to infection and to identify the antigenic determinants in Streptococcus iniae that are best suited for vaccine development. Our central hypothesis was that anti-bacterial immunity in trout and tilapia can only be acquired by combining "innate" NCC responses with antibody responses to polysaccharide antigens. These Objectives were accomplished by experiments delineated by the following Specific Aims: Specific aim (SA) #1 (USA) "Clone and Identify the Apoptosis Regulatory Genes in NCC"; Specific aim #2 (USA)"Identify Regulatory Factors that Control NCC Responses to S. iniae"; Specific aim #3 (Israel) "Characterize the Biological Properties of the S. iniae Capsular Polysaccharide"; and Specific aim #4 (Israel) "Development of an Acellular Vaccine". Our model of S. iniae pathogenesis encompassed two approaches, identify apoptosis regulatory genes and proteins in tilapia that affected NCC activities (USA group) and determine the participation of S.iniae capsular polysaccharides as potential immunogens for the development of an acellular vaccine (Israel group). We previously established that it was possible to immunize tilapia and trout against experimental S. difficile/iniaeinfections. However these studies indicated that antibody responses in protected fish were short lived (3-4 months). Thus available vaccines were useful for short-term protection only. To address the issues of regulation of pathogenesis and immunogens of S. iniae, we have emphasized the role of the innate immune response regarding activation of NCC and mechanisms of invasiveness. Considerable progress was made toward accomplishing SA #1. We have cloned the cDNA of the following tilapia genes: cellular apoptosis susceptibility (CAS/AF547173»; tumor necrosis factor alpha (TNF / A Y 428948); and nascent polypeptide-associated complex alpha polypeptide (NACA/ A Y168640). Similar attempts were made to sequence the tilapia FasLgene/cDNA, however these experiments were not successful. Aim #2 was to "Identify Regulatory Factors that Control NCC Responses to S. iniae." To accomplish this, a new membrane receptor has been identified that may control innate responses (including apoptosis) of NCC to S. iniae. The receptor is a membrane protein on teleost NCC. This protein (NCC cationic antimicrobial protein-1/ncamp-1/AAQ99138) has been sequenced and the cDNA cloned (A Y324398). In recombinant form, ncamp-l kills S. iniae in vitro. Specific aim 3 ("Characterize the Biological Properties of the S.iniae Capsular Polysaccharide") utilized an in- vitro model using rainbow trout primary skin epithelial cell mono layers. These experiments demonstrated colonization into epithelial cells followed by a rapid decline of viable intracellular bacteria and translocation out of the cell. This pathogenesis model suggested that the bacterium escapes the endosome and translocates through the rainbow trout skin barrier to further invade and infect the host. Specific aim #4 ("Development of an Acellular Vaccine") was not specifically addressed. These studies demonstrated that several different apoptotic regulatory genes/proteins are expressed by tilapia NCC. These are the first studies demonstrating that such factors exist in tilapia. Because tilapia NCC bind to and are activated by S. iniae bacterial DNA, we predict that the apoptotic regulatory activity of S. iniae previously demonstrated by our group may be associated with innate antibacterial responses in tilapia.