Expression and function of transient receptor potential channels in the female bovine reproductive tract

© 2016 Elsevier Inc. The epithelium lining the oviduct is critical for early reproductive events, many of which are mediated via intracellular calcium ions. Despite this, little is known about the regulation of calcium homeostasis in the oviductal epithelium. Epithelial transient receptor potential channels (TRPCs) modulate calcium flux in other tissues, and their expression and functional regulation have therefore been examined using the bovine oviduct as a model for the human. The effects of FSH, LH, 17β-estradiol, and progesterone on TRPCs expression and intracellular calcium flux were determined. Transient receptor potential channels 1, 2, 3, 4, and 6 were expressed in the bovine reproductive tract, and their gene expression varied throughout the estrous cycle. In more detailed studies undertaken on TRPC1 and 6, we show that protein expression varied through the estrus cycle; specifically, 17β-estradiol, FSH, and LH individually and in combination upregulated TRPC1 and 6 expression in cultured bovine oviduct epithelial cells although progesterone antagonized these effects. Functional studies showed changes in calcium mobilization in bovine oviduct epithelial cells were dependent on TRPCs. In conclusion, TRPC1, 2, 3, 4, and 6 are present in the epithelium lining the bovine oviduct, and TRPC1 and 6 vary through the estrous cycle suggesting an important role in early reproductive function

A study of relativistic electron flux enhancements in the Earth's outer radiation belt

The relativistic electron distribution that occupies the outer radiation belt has been observed to vary significantly during intervals of disturbed solar wind conditions. Of particular interest are the order of magnitude increases in the relativistic electron flux that sometimes, but not always, follow the onset of a magnetic storm. These currently unpredictable relativistic electron flux enhancements are potentially hazardous during space missions causing radiation damage to spacecraft instrumentation and to humans. The work presented here establishes the conditions in the solar wind that lead to such flux enhancements. In addition, through the combined analysis of electron and wave data we provide essential constraints for the numerous proposed mechanisms for the acceleration of relativistic electrons in the outer radiation belt. The study uses data from the two STRV micro-satellites, which uncommonly are in the necessary orbit to provide coverage of almost the total electron population of the outer radiation belt essential for understanding the dynamics of the electron population. Data on the > 0.75 MeV energy electrons is used to investigate the relationship between the electron flux enhancements during magnetic storms and the coincident solar wind and geomagnetic conditions. Three distinct different types of electron responses arc identified, with outcomes that are shown to strongly depend on the solar wind speed and in particular the interplanetary magnetic field orientation during the magnetic storm recovery phase. A number of the electron acceleration mechanisms proposed to explain relativistic electron flux enhancements are driven by Pc5 pulsations in the magnetosphere. We thus investigate the relationship between these waves and electron response during magnetic storms. The findings point to a strong correlation between the Pc5 energy present during flux enhancement events and the size of the subsequent flux increase. However, the strength of the Pc5 power falls off quickly in the vicinity of the peak flux enhancement. In order to separate non-adiabatic processes, such as electron loss and most importantly heating, from adiabatic effects, we represent the electron data in a canonical coordinate system of the three adiabatic invariants. M, J and &phis; during two case studies. Using this method we identify an internal source of accelerated relativistic electrons and a further source of relativistic electrons at larger L supplied via substorm injections and inward radial diffusion. We also confirm the absence of either source of relativistic electrons when the IMF is northward during the recovery phase. Finally we use the results to help validate or discredit the various proposed electron acceleration mechanisms and end by identifying the mechanism that fits most convincingly with the analysis

Factor Analysis in a Model with Rational Expectations

DSGE models are characterized by the presence of expectations as explanatory variables. To use these models for policy evaluation, the econometrician must estimate the parameters of expectation terms. Standard estimation methods have several drawbacks, including possible lack or weakness of identification of the parameters, misspecification of the model due to omitted variables or parameter instability, and the common use of inefficient estimation methods. Several authors have raised concerns over the implications of using inappropriate instruments to achieve identification. In this paper we analyze the practical relevance of these problems and we propose to combine factor analysis for information extraction from large data sets and GMM to estimate the parameters of systems of forward looking equations. Using these techniques, we evaluate the robustness of recent findings on the importance of forward looking components in the equations of a standard New-Keynesian model.

Factor analysis in a New-Keynesian model

New-Keynesian models are characterized by the presence of expectations as explanatory variables. To use these models for policy evaluation, the econometrician must estimate the parameters of expectation terms. Standard estimation methods have several drawbacks, including possible lack of identification of the parameters, misspecification of the model due to omitted variables or parameter instability, and the common use of inefficient estimation methods. Several authors have raised concerns over the validity of commonly used instruments to achieve identification. In this paper we analyze the practical relevance of these problems and we propose remedies to weak identification based on recent developments in factor analysis for information extraction from large data sets. Using these techniques, we evaluate the robustness of recent findings on the importance of forward looking components in the equations of the New-Keynesian model. JEL Classification: E5, E52, E58determinacy of equilibrium, factor analysis, forward looking output equation, New-Keynesian Phillips Curve, Rational Expectations, Taylor rule

Modelling aspects of oviduct fluid formation in vitro

© 2017 Society for Reproduction and Fertility. Oviduct fluid is the microenvironment that supports early reproductive processes including fertilisation, embryo cleavage and genome activation. However, the composition and regulation of this critical environment remain rather poorly defined. This study uses an in vitro preparation of the bovine oviduct epithelium to investigate the formation and composition of in vitro-derived oviduct fluid (ivDOF) within a controlled environment. We confirm the presence of oviduct-specific glycoprotein 1 in ivDOF and show that the amino acid and carbohydrate content resembles that of previously reported in vivo data. In parallel, using a different culture system, a panel of oviduct epithelial solute carrier genes and the corresponding flux of amino acids within ivDOF in response to steroid hormones were investigated. We next incorporated fibroblasts directly beneath the epithelium. This dual culture arrangement represents more faithfully the in vivo environment and impacts on ivDOF composition. Lastly, physiological and pathophysiological endocrine states were modelled and their impact on the in vitro oviduct preparation was evaluated. These experiments help clarify the dynamic function of the oviduct in vitro and suggest a number of future research avenues, such as investigating epithelial-fibroblast interactions, probing the molecular aetiologies of subfertility and optimising embryo culture media

Organización económica y social de los aztecas y culturas que les precedieron

1 archivo PDF (136 páginas)Se expone como el desarrollo social está determinado, en gran medida por las condiciones económicas de producción y sustento de la vida humana. La evolución de la sociedad está, por tanto, asociada a la capacidad productiva alcanzada por la comunidad, como lo está también, el desarrollo del urbanismo y el paso a la civilización. Bajo estas bases se puede intentar establecer el grado de evolución alcanzado por las culturas mesoamericanas que precedieron al Imperio Azteca, definir sus características económicas y sociales y describir los lazos de interdependencia que mantuvieron, este e es el objeto de la primera parte del trabajo. En la segunda parte, fundamentalmente, se estudia la organización económica y social de los aztecas, se hace un análisis: de la estructura económica, de la propiedad de la tierra y de la estructura social. Por último, se explica la influencia que tuvo la religión sobre la concepción del mundo. Intentando así responder a la pregunta, si el Imperio Azteca fue una dictadura sanguinaria como lo explica la descripción de los sacrificios humanos que practicaban: ¿Por qué se mantuvo? ¿Cuáles fueron las bases de su hegemonía

MICROLAN file transfer program for microprocessors

The age of automation has established its foothold in today's society. Computerization now affects almost everyone's job, and sharing of information is vital to successful job performance. Manual transfer of information is inefficient and prone to error, so another means is needed. One option is computer networking. Both Local Area Networks and long-haul networks presently exist, but they are either very expensive or hardware dependent. It would normally require a long lead time and high costs for the military to acquire an information transfer system. To provide a readily available, low-cost file transfer system, the authors developed an assembly language program named MICROLAN, which is written to work with three of the main microcomputer operating systems (CP/M-80, CP/M-86, and IIS. DOS) and to take advantage of RS232 technology. MICROLAN was tested successfully for file transfer at up to 4800 baud, and suggestions have been included as to possible uses for MICROLAN in the military environment. Additionally, possible methods for upgrading MICROLAN are also included.Lieutenant, United States NavyCaptain, United States Air ForceApproved for public release; distribution is unlimited

TB10: A Comparison of Arch-yarding and Ground-skidding of Pine Sawlogs in the University of Maine Forest

The decision whether to use a trailing-arch or operate by ground-skidding methods may face many sawlog producers. This case study attempted to determine statistically whether there existed significant differences between the two methods of operation by examining the various activities performed by a crawler-type tractor within the arch-yarding and ground-skidding phases of a harvesting system.https://digitalcommons.library.umaine.edu/aes_techbulletin/1192/thumbnail.jp

Human embryos from overweight and obese women display phenotypic and metabolic abnormalities

STUDY QUESTION Is the developmental timing and metabolic regulation disrupted in embryos from overweight or obese women? SUMMARY ANSWER Oocytes from overweight or obese women are smaller than those from women of healthy weight, yet post-fertilization they reach the morula stage faster and, as blastocysts, show reduced glucose consumption and elevated endogenous triglyceride levels. WHAT IS KNOWN ALREADY Female overweight and obesity is associated with infertility. Moreover, being overweight or obese around conception may have significant consequences for the unborn child, since there are widely acknowledged links between events occurring during early development and the incidence of a number of adult disorders. STUDY DESIGN, SIZE, DURATION We have performed a retrospective, observational analysis of oocyte size and the subsequent developmental kinetics of 218 oocytes from 29 consecutive women attending for ICSI treatment and have related time to reach key developmental stages to maternal bodyweight. In addition, we have measured non-invasively the metabolic activity of 150 IVF/ICSI embryos from a further 29 consecutive women who donated their surplus embryos to research, and have related the data retrospectively to their body mass index (BMI). PARTICIPANTS/MATERIALS, SETTING, METHODS In a clinical IVF setting, we compared oocyte morphology and developmental kinetics of supernumerary embryos collected from overweight and obese women, with a BMI in excess of 25 kg/m2 to those from women of healthy weight. A Primovision Time-Lapse system was used to measure developmental kinetics and the non-invasive COnsumption/RElese of glucose, pyruvate, amino acids and lactate were measured on spent droplets of culture medium. Total triglyceride levels within individual embryos were also determined. MAIN RESULTS AND THE ROLE OF CHANCE Human oocytes from women presenting for fertility treatment with a BMI exceeding 25 kg/m2 are smaller (R2 = −0.45; P = 0.001) and therefore less likely to complete development post-fertilization (P < 0.001). Those embryos that do develop reach the morula stage faster than embryos from women of a BMI < 25 kg/m2

Determinants of thermal homeostasis in the preimplantation embryo: a role for the embryo's central heating system?

A number of factors may impinge on thermal homeostasis in the early embryo. The most obvious is the ambient temperature in which development occurs. Physiologically, the temperature in the lumen of the female tract is typically lower than the core body temperature, yet rises at ovulation in the human, while in an IVF setting, embryos are usually maintained at core body temperature. However, internal cellular developmental processes may modulate thermal control within the embryo itself, especially those occurring in the mitochondria which generate intracellular heat through proton leak and provide the embryo with its own 'central heating system'. Moreover, mitochondrial movements may serve to buffer high local intracel-lular temperatures. It is also notable that the preimplantation stages of development would generate proportionally little heat within their mitochondria until the blastocyst stage as mitochondrial metabolism is comparatively low during the cleavage stages. Despite these data, the specific notion of thermal control of preimplantation development has received remarkably scant consideration. This opinion paper illustrates the lack of reliable quantitative data on these markers and identifies a major research agenda which needs to be addressed with urgency in view of laboratory conditions in which embryos are maintained as well as climate change-derived heat stress which has a negative effect on numerous clinical markers of early human embryo development. Keywords Thermal regulation · Embryo development · Mitochondrial function In this opinion paper, factors determining the maintenance of temperature in preimplantation embryos are examined, a topic which has assumed special significance due to the impact of heat stress on reproductive medicine associated with climate change and global warming [1]. Effects of excess heat on the early events of mammalian reproduction include diminished gamete and embryo development and viability, increased mitochondrial activity and associated production of reactive oxygen species and decreased offspring weight. These effects have been well-summarised for the human by Boni et al. [2] and in farm animals by Hansen [3]. The focus here is on physiological factors that may impinge on thermal homeostasis during the preimplantation stages of development, especially on the heat-generating capacity of mitochondria within the embryo, a topic which has attracted much less attention than the well-known involvement of mito-chondria in other early cellular functions including apoptosis, [Ca ++ ]i regulation, reactive oxygen species formation, redox status, metabolic regulation, maternal inheritance [4] and the provision of a central signalling hub [5]. Factors involved in thermal homeostasis in early embryos have been identified from a narrative review of the literature generated through a search of online databases to identify existing peer-reviewed literature on preimplantation embryos and somatic cells where appropriate. Pre-prints and the grey literature have been excluded. Ambient temperature in situ and impact on the development of the gametes and early embryo Somewhat counterintuitively, the temperatures to which mammalian gametes and preimplantation embryos are exposed in situ (the ovarian follicle, oviduct and uterus) ar