Download or read book Mathematical Model of the Reproductive Endocrine System in Male Sheep written by Teuku Reza Ferasyi and published by . This book was released on 2007 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: [Truncated abstract] The activity of the reproductive endocrine axis is the result of interactions among many organs and tissues, particularly the hypothalamus, pituitary gland and gonad. However, it depends on more than the communication between anatomical structures because it is also affected by genotype, internal factors (e.g., metabolic inputs) and external factors (e.g., photoperiod, socio-sexual cues, stress, nutrition). This multifactorial complexity makes it difficult to use animal experimentation to investigate the pathways and mechanisms involved. Therefore, in this study, I have turned to mathematical modelling. The general hypothesis was that, by modelling the hormonal feedback loop that links the hypothalamus, pituitary gland and gonad, I would be able to discover the critical control points in this homeostatic system. This would allow me to inform and direct research into the processes that control reproduction, including inputs from environmental factors. My studies began with the development of a model of the negative feedback loop through which testosterone controls the secretion of pulses of gonadotrophin-releasing hormone (GnRH) by the hypothalamus. The model incorporated two critical factors: testosterone concentration and a time delay in the inhibition of the activity of the GnRH 'pulse generator' by testosterone. The general assumptions were: i) there are two positive feedforward processes (GnRH pulses stimulate LH pulses, and, in turn, LH pulses stimulate testosterone secretion); ii) testosterone exerts negative feedback that reduces the frequency of GnRH pulses. The model incorporated a group of equations that represent the GnRH pulse generator, through which the inhibitory effect of testosterone acted to reduce GnRH pulse frequency. Simulations were run with various values for the time delay in feedback and, as model development progressed, the simulations were extended to include combinations of time delays and levels of sensitivity of the GnRH pulse generator to inhibition by testosterone. The output of the simulations showed clearly that a time delay in negative feedback, as well as the concentration of testosterone, can greatly affect the frequency of GnRH pulses and the shape of the GnRH secretory profile. Importantly, the effect of the time delay depends on the sensitivity of the pulse generator to testosterone. In addition, the simulations suggested two additional components that might be involved in the control of the GnRH pulse generator: i) a delay in the rate of adaptation to a change in steroid feedback; and ii) a minimum pulse interval (maximum frequency). These studies iii therefore suggest that the regulation of the activity of the GnRH pulse generator, and thus the frequency and profile of GnRH and LH pulses, requires interactions among these four components. These interactions should be tested in animal experimentation. In the next stage, I extended the model so I could test whether the feedback delay might involve the process of aromatization in which testosterone is converted to oestradiol at brain level. ... This information can be used to direct future experimental studies that will help us to understand the factors that underlie the dynamic behaviour of the hypothalamic and pituitary systems that control reproduction.
Download or read book Reproductive Genomics in Domestic Animals written by Zhihua Jiang and published by John Wiley & Sons. This book was released on 2011-06-17 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reproductive Genomics in Domestic Animals is a thorough examination of genomics in the livestock industry, encompassing genome sciences, genome biotechnology, and reproduction. Recent developments in molecular genetics and genomics have enabled scientists to identify and characterize genes contributing to the complexity of reproduction in domestic animals, allowing scientists to improve reproductive traits. Providing the livestock industry with essential tools for enhancing reproductive efficiency, Reproductive Genomics in Domestic Animals surveys the current status of reproductive genomes and looks to the future direction of research.
Download or read book Mammal Societies written by Tim Clutton-Brock and published by John Wiley & Sons. This book was released on 2016-04-20 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book aims to integrate our understanding of mammalian societies into a novel synthesis that is relevant to behavioural ecologists, ecologists, and anthropologists. It adopts a coherent structure that deals initially with the characteristics and strategies of females, before covering those of males, cooperative societies and hominid societies. It reviews our current understanding both of the structure of societies and of the strategies of individuals; it combines coverage of relevant areas of theory with coverage of interspecific comparisons, intraspecific comparisons and experiments; it explores both evolutionary causes of different traits and their ecological consequences; and it integrates research on different groups of mammals with research on primates and humans and attempts to put research on human societies into a broader perspective.
Download or read book Williams Textbook of Endocrinology E Book written by Shlomo Melmed and published by Elsevier Health Sciences. This book was released on 2019-11-14 with total page 2239 pages. Available in PDF, EPUB and Kindle. Book excerpt: Expertly bridging the gap between basic science and clinical information, Williams Textbook of Endocrinology, 14th Edition, brings together an outstanding collection of world-renowned authors to provide authoritative discussions of the full spectrum of adult and pediatric endocrine system disorders. New chapters and significant revisions throughout keep you up to date with recent advances in medications, therapies, clinical trials, and more. This essential reference is a must-have resource for endocrinologists, endocrine surgeons, gynecologists, internists, pediatricians, and other clinicians who need current, comprehensive coverage of this multifaceted field. Up to date with recent advances in medications, therapies, and clinical trials. Provides state-of-the-art coverage of diabetes, metabolic syndrome, metabolic bones disorders, obesity, thyroid disease, testicular disorders, newly defined adrenal disorders and much more - all designed to help you provide optimal care to every patient. Contains new chapters on Global Burden of Endocrine Disease, Navigation of Endocrine Guidelines, and Transgender Endocrinology. Includes significant updates to the Diabetes section, including a new chapter on Physiology of Insulin Secretion and greater coverage of Type 2 Diabetes. Presents current information in a highly illustrated, user-friendly format for quick reference.
Download or read book Endocrine Disrupters and Metabolism written by Yann Gibert and published by Frontiers Media SA. This book was released on 2020-01-20 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cumulated Index Medicus written by and published by . This book was released on 2000 with total page 1844 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Index Medicus written by and published by . This book was released on 2003 with total page 1780 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1963- include as pt. 2 of the Jan. issue: Medical subject headings.
Download or read book Special Reports written by Robert Snyder and published by . This book was released on 1993 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Subject Index of Extramural Research Administered by the National Cancer Institute written by and published by . This book was released on 1978 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current information about research grants and contracts supported by the National Cancer Institute. Subject listing gives contract or grant number and topic. Investigator, grant number, and contract number indexes.
Download or read book Subject Index of Current Extramural Research Administered by the National Cancer Institute written by National Cancer Institute (U.S.) and published by . This book was released on 1977 with total page 708 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides information concerning research grants and contracts supported by the National Cancer Institute.
Download or read book Research Grants Index written by National Institutes of Health (U.S.). Division of Research Grants and published by . This book was released on 1975 with total page 1224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research Awards Index written by and published by . This book was released on 1985 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Encyclopedia of Animal Behavior written by and published by Elsevier. This book was released on 2009-04-01 with total page 2662 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Encyclopedia of Animal Behavior, Three Volume Set has engaged with great success the efforts of many of the best behavioral biologists of the 21st century. Section editors drawn from the most accomplished behavioral scientists of their generation have enrolled an international cast of highly respected thinkers and writers all of whom have taken great care and joy in illuminating every imaginable corner of animal behavior. This comprehensive work covers not only the usual topics such as communication, learning, sexual selection, navigation, and the history of the field, but also emerging topics in cognition, animal welfare, conservation, and applications of animal behavior. The large section on animal cognition brings together many of the world's experts on the subject to provide a comprehensive overview of this rapidly developing area. Chapters relating to animal welfare give a full view of behavioral interactions of humans with companion animals, farm animals, and animals in the wild. The key role of animal behavior in conservation biology receives broad attention, including chapters on topics such as the effects of noise pollution, captive breeding, and how the behavioral effects of parasites interacts with conservation issues. Animal behavior in environmental biology is highlighted in chapters on the effects of endocrine disruptors on behavior and a large number of chapters on key species, such as wolves, chimpanzees, hyenas and sharks. Clear, accessible writing complements a wealth of information for undergraduate college students about the essential concepts of animal behavior and the application of those concepts across the field. In-depth coverage of concepts, methods, and exemplar organisms serves the needs of graduate students and professionals in the field. From the use of behavior in assessing the welfare of pigs to the social behavior of insects, from animal empathy to bat brains, this authoritative reference, with its in-depth introductory articles, rich array of illustrations, interactive cross-referenced links, and numerous suggested readings, can guide the student or the professional to an expanded appreciation of the far-flung world of animal behavior. An invaluable tool for teaching and a source of enrichment and detail for any topic covered in an animal behavior course, the Encyclopedia of Animal Behavior is the definitive reference work in its field and will be for years to come. Comprehensive work which covers the usual topics along with emerging areas of animal behavior This encyclopedia contains clear, accessible writing and is well illustrated, including an online video, complimenting a wealth of information As an online reference, this work will be subject to period updating. This ensures that the work always remains current Contains in-depth introductions to the material that make each well-illustrated section come alive with the best the new content the discipline has to offer Glossary includes a compendium of behavioral terms that form a succinct mosaic of virtually every concept and phenomenon related to animal behavior Section editors, drawn from around the world, represent the best and the brightest among today's behavioral biologists and have recruited a broad range of internationally recognized experts Editors-in-Chief are experienced scientists and writers who between them have authored or edited eight books and teach courses in animal behavior at their respective universities
Download or read book Bibliography of Agriculture with Subject Index written by and published by . This book was released on 2000 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bibliography of Agriculture written by and published by . This book was released on 1976 with total page 1732 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Current Population Research written by and published by . This book was released on 1966 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Williams Textbook of Endocrinology 14 Edition South Asia Edition 2 Vol Set E Book written by Shlomo Melmed and published by Elsevier India. This book was released on 2020-06-30 with total page 2250 pages. Available in PDF, EPUB and Kindle. Book excerpt: Williams Textbook of Endocrinology, 14 Edition: South Asia Edition, 2 Vol SET - E-Book
