5,210 research outputs found
Effect of Estradiol-17β on Placental Size
Meishan embryos transferred to recipient females on day 2.5 are larger, contain greater numbers of trophectoderm cells, and secrete greater amounts of estradiol-17β when gestated in a Yorkshire compared with Meishan uterus to day 12. Additionally, placentae of Meishan conceptuses are larger when gestated in a Yorkshire compared with Meishan uterus throughout gestation. Embryonic estradiol-17β secretion during elongation on day 12 to 13 of gestation is temporally associated with endometrial secretion of growth factors, including IGF-I, which has been shown to increase mitotic rate in the trophectoderm of pig embryos. This experiment was conducted to determine if estradiol-17β administration to Meishan females at the time of conceptus elongation would increase placental size at term. Meishan females (n=12) were checked twice daily for estrus (0700 and 1900), and each bred to a Meishan boar at 0 and 24 h after the onset of estrus (day 0). Females were randomly assigned in equal numbers to receive injections of sesame oil (VEH) starting on day 12 (CONTROL), 1 mg of estradiol-17β in VEH starting on day 12 (E212), or 1 mg of estradiol-17β in VEH starting day 13 (E213). The injections were initiated at 0700 or 1900 (corresponding to the time of day they first exhibited estrus) and continued at 6-hour intervals for 48 hours, resulting in 8 mg of estradiol-17β given in eight injections. Pregnant females were killed on day 112 of gestation and ovulation rate, litter size, implantation site length, fetal weight, crown-rump length, placental weight, and placental surface area were quantified. There were no differences among E212, E213, and CONTROL females in ovulation rate or litter size, which averaged 16.3 ± .7 and 11.8 ± .7, respectively. Fetal weight and crown-rump length were not different (P\u3e.10) among E212, E213, and CONTROL females, averaging 802 ± 26 g and 24.3 ± .3 cm. Placentae were markedly heavier (176 ± 14 and 174 ± 16 g vs. 134 ± 10 g,
ShapeFit and ShapeKick for Robust, Scalable Structure from Motion
We introduce a new method for location recovery from pair-wise directions
that leverages an efficient convex program that comes with exact recovery
guarantees, even in the presence of adversarial outliers. When pairwise
directions represent scaled relative positions between pairs of views
(estimated for instance with epipolar geometry) our method can be used for
location recovery, that is the determination of relative pose up to a single
unknown scale. For this task, our method yields performance comparable to the
state-of-the-art with an order of magnitude speed-up. Our proposed numerical
framework is flexible in that it accommodates other approaches to location
recovery and can be used to speed up other methods. These properties are
demonstrated by extensively testing against state-of-the-art methods for
location recovery on 13 large, irregular collections of images of real scenes
in addition to simulated data with ground truth
Universal magnetic and structural behaviors in the iron arsenides
Commonalities among the order parameters of the ubiquitous antiferromagnetism
present in the parent compounds of the iron arsenide high temperature
superconductors are explored. Additionally, comparison is made between the well
established two-dimensional Heisenberg-Ising magnet, KNiF and iron
arsenide systems residing at a critical point whose structural and magnetic
phase transitions coincide. In particular, analysis is presented regarding two
distinct classes of phase transition behavior reflected in the development of
antiferromagnetic and structural order in the three main classes of iron
arsenide superconductors. Two distinct universality classes are mirrored in
their magnetic phase transitions which empirically are determined by the
proximity of the coupled structural and magnetic phase transitions in these
materials.Comment: 6 pages, 4 figure
Anti-CD20 therapy depletes activated myelin-specific CD8+ T cells in multiple sclerosis.
CD8+ T cells are believed to play an important role in multiple sclerosis (MS), yet their role in MS pathogenesis remains poorly defined. Although myelin proteins are considered potential autoantigenic targets, prior studies of myelin-reactive CD8+ T cells in MS have relied on in vitro stimulation, thereby limiting accurate measurement of their ex vivo precursor frequencies and phenotypes. Peptide:MHC I tetramers were used to identify and validate 5 myelin CD8+ T cell epitopes, including 2 newly described determinants in humans. The validated tetramers were used to measure the ex vivo precursor frequencies and phenotypes of myelin-specific CD8+ T cells in the peripheral blood of untreated MS patients and HLA allele-matched healthy controls. In parallel, CD8+ T cell responses against immunodominant influenza epitopes were also measured. There were no differences in ex vivo frequencies of tetramer-positive myelin-specific CD8+ T cells between MS patients and control subjects. An increased proportion of myelin-specific CD8+ T cells in MS patients exhibited a memory phenotype and expressed CD20 compared to control subjects, while there were no phenotypic differences observed among influenza-specific CD8+ T cells. Longitudinal assessments were also measured in a subset of MS patients subsequently treated with anti-CD20 monoclonal antibody therapy. The proportion of memory and CD20+ CD8+ T cells specific for certain myelin but not influenza epitopes was significantly reduced following anti-CD20 treatment. This study, representing a characterization of unmanipulated myelin-reactive CD8+ T cells in MS, indicates these cells may be attractive targets in MS therapy
Selection for Litter Size by Using the Ratio of Piglet Weight: Placental Weight as a Measure of Placental Efficiency
The Chinese have been selectively breeding pigs for 7,000 to 10,000 years for increased numbers of pigs born, regardless of birth weight, indirectly resulting in the optimization of placental size and vascularity. In the United States, pig producers have generally selected for larger piglets at birth, resulting in a marked variation in placental size and vascularity. This tremendous variation in placental size and vascularity present within a litter may be ultimately limiting litter size. Therefore, by selecting against the large relatively avascular placentae, the potential for dramatically increasing litter size exists
Differential Prepartum and Postpartum Growth Patterns of Yorkshire and Meishan Piglets Gestated in the Same Uterine Environment
While Yorkshire fetal growth appears to depend on increasing placental size, more extensive vascularization of a smaller placenta appears to support Meishan fetal growth. Further studies are needed to extend our knowledge of the mechanisms controlling placental growth and vascularization. The ability to manipulate conceptus size may allow producers the opportunity to increase litter size in domestic pigs. More piglets farrowed per sow per year combined with the effects of fetal genotype on postpartum growth rate, as confirmed by the current study, would allow more efficient pork production
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Shear-Wave Splitting and Mantle Flow Beneath the Colorado Plateau and its Boundary with the Great Basin
Shear-wave splitting measurements from SKS and SKKS phases show fast polarization azimuths that are subparallel to North American absolute plate motion within the central Rio Grande Rift (RGR) and Colorado Plateau (CP) through to the western rim of the CP, with anisotropy beneath the CP and central RGR showing a remarkably consistent pattern with a mean fast azimuth of 4 degrees +/- degrees 6 E of N. Approaching the rim from the southeast, fast anisotropic directions become north-northeast-south-southwest (NNE-SSW), rotate counter clockwise to north-south in the CP-GB transition, and then to NNW-SSE in the western Great Basin ( GB). This change is coincident with uppermost mantle S-wave velocity perturbations that vary from +4% beneath the western CP and the eastern edge of the Marysvale volcanic field to about -8% beneath the GB. Corresponding delay times average 1.5 sec beneath the central CP, decrease to approximately 0.8 sec near the CP-GB transition, and increase to about 1.2 sec beneath the GB. For the central CP, we suggest anisotropy predominantly controlled by North American plate motion above the asthenosphere. The observed pattern of westward-rotating anisotropy from the western CP through the CP-GB transition may be influenced to asthenospheric flow around a CP lithospheric keel and/or by vertical flow arising from edge-driven small-scale convection. The anisotropic transition from the CP to the GB thus marks a first-order change from absolute plate motion dominated lithosphere-asthenosphere shear to a new regime controlled by regional flow processes. The NNW-SSE anisotropic fast directions of split SKS waves in the eastern GB area are part of a broad circular pattern of seismic anisotropic fast direction in the central GB that has recently been hypothesized to be due to toroidal flow around the sinking Juan de Fuca-Gorda slab.National Science Foundation EAR 9706094, 9707188, 9707190, 0207812Los Alamos National Laboratory Institute of Geophysics and Planetary PhysicsNational Science Foundation Cooperative EAR-000430Department of Energy National Nuclear Security AdministrationGeological Science
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