74 research outputs found

    Effect of ovulatory follicle size on luteal function, pregnancy rate, and late embryonic/fetal mortality in beef cattle

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    The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract, appears in the public.pdf file.Title from PDF of title page (University of Missouri--Columbia, viewed on January 25, 2011).Thesis advisor: Dr. Michael F. Smith.Vita.Ph. D. University of Missouri--Columbia, 2009.Previous reports indicate that ovulation of small dominant follicles resulted in reduced pregnancy rates compared ovulation of large follicles in cattle. A reciprocal embryo transfer approach was used to differentiate between oocyte competence and uterine environment factors that affect establishment of pregnancy following induced single ovulations of small follicles. Embryos from donor cows that ovulated a small follicle ( [less than] 12.5 mm) were transferred into recipient cows that ovulated a large follicle ([equal to] 12.5 mm) and vice versa resulting in the following treatment groups: small to large (S-L; primary effects of oocyte quality; n = 111), large to small (L-S; primary effects of uterine environment; n = 122), small to small (S-S; negative control; n = 71), and large to large (L-L; positive control; n = 50). The probability of recovering a fertilized and live embryo 7 d after breeding increased as the diameter of the ovulatory follicle increased (p = 0.01). As ovulatory follicle diameter and serum concentrations of progesterone at embryo transfer increased in the recipient cow, the probability of pregnancy increased (p = 0.05 and [less than] 0.001, respectively); however neither follicle size nor progesterone at ET in the donor cow was significant (p [greater than] 0.3). In summary, ovulatory diameter at GnRH2 was positively associated with recovery of a live embryo (possibly indicating improved oocyte competence and (or) an early uterine environment that was more conducive to embryonic/fetal development in cows that ovulated a large follicle). Pregnancy establishment following embryo transfer was related to the uterine environment established by the ovulatory follicle independent of oocyte quality.Includes bibliographical reference

    X-Ray Optics at NASA Marshall Space Flight Center

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    NASA's Marshall Space Flight Center (MSFC) engages in research, development, design, fabrication, coating, assembly, and testing of grazing-incidence optics (primarily) for x-ray telescope systems. Over the past two decades, MSFC has refined processes for electroformed-nickel replication of grazing-incidence optics, in order to produce high-strength, thin-walled, full-cylinder x-ray mirrors. In recent years, MSFC has used this technology to fabricate numerous x-ray mirror assemblies for several flight (balloon, rocket, and satellite) programs. Additionally, MSFC has demonstrated the suitability of this technology for ground-based laboratory applications-namely, x-ray microscopes and cold-neutron microscopes and concentrators. This mature technology enables the production, at moderately low cost, of reasonably lightweight x-ray telescopes with good (15-30 arcsecond) angular resolution. However, achieving arcsecond imaging for a lightweight x-ray telescope likely requires development of other technologies. Accordingly, MSFC is conducting a multi-faceted research program toward enabling cost-effective production of lightweight high-resolution x-ray mirror assemblies. Relevant research topics currently under investigation include differential deposition for post-fabrication figure correction, in-situ monitoring and control of coating stress, and direct fabrication of thin-walled full-cylinder grazing-incidence mirrors

    X-Ray Optics at NASA Marshall Space Flight Center

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    NASA's Marshall Space Flight Center (MSFC) engages in research, development, design, fabrication, coating, assembly, and testing of grazing-incidence optics (primarily) for x-ray telescope systems. Over the past two decades, MSFC has refined processes for electroformed-nickel replication of grazing-incidence optics, in order to produce high-strength, thin-walled, full-cylinder x-ray mirrors. In recent years, MSFC has used this technology to fabricate numerous x-ray mirror assemblies for several flight (balloon, rocket, and satellite) programs. Additionally, MSFC has demonstrated the suitability of this technology for ground-based laboratory applications-namely, x-ray microscopes and cold-neutron microscopes and concentrators. This mature technology enables the production, at moderately low cost, of reasonably lightweight x-ray telescopes with good (15-30 arcsecond) angular resolution. However, achieving arcsecond imaging for a lightweight x-ray telescope likely requires development of other technologies. Accordingly, MSFC is conducting a multi-faceted research program toward enabling cost-effective production of lightweight high-resolution x-ray mirror assemblies. Relevant research topics currently under investigation include differential deposition for post-fabrication figure correction, in-situ monitoring and control of coating stress, and direct fabrication of thin-walled full-cylinder grazing-incidence mirrors

    Contribution of copy number variants to schizophrenia from a genome-wide study of 41,321 subjects

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    Copy number variants (CNVs) have been strongly implicated in the genetic etiology of schizophrenia (SCZ). However, genome-wide investigation of the contribution of CNV to risk has been hampered by limited sample sizes. We sought to address this obstacle by applying a centralized analysis pipeline to a SCZ cohort of 21,094 cases and 20,227 controls. A global enrichment of CNV burden was observed in cases (OR=1.11, P=5.7×10−15), which persisted after excluding loci implicated in previous studies (OR=1.07, P=1.7 ×10−6). CNV burden was enriched for genes associated with synaptic function (OR = 1.68, P = 2.8 ×10−11) and neurobehavioral phenotypes in mouse (OR = 1.18, P= 7.3 ×10−5). Genome-wide significant evidence was obtained for eight loci, including 1q21.1, 2p16.3 (NRXN1), 3q29, 7q11.2, 15q13.3, distal 16p11.2, proximal 16p11.2 and 22q11.2. Suggestive support was found for eight additional candidate susceptibility and protective loci, which consisted predominantly of CNVs mediated by non-allelic homologous recombination

    Toward Large-Area Sub-Arcsecond X-Ray Telescopes

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    The future of x-ray astronomy depends upon development of x-ray telescopes with larger aperture areas (>1 sq m) and finer angular resolution(100 sq m) of lightweight (1 kg/sq m areal density) high quality mirrors-possibly entailing active (in-space adjustable) alignment and figure correction. This paper discusses relevant programmatic and technological issues and summarizes progress toward large area sub-arcsecond x-ray telescopes. Key words: X-ray telescopes, x-ray optics, active optics, electroactive devices, silicon mirrors, differential deposition, ion implantation
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