Publications by authors named "Dwyer C"

Up to one-third of dairy calves are born after dystocia and this is a major cause of calf mortality. This study investigated the neonatal physiology, survival, health and subsequent growth of dairy calves following dystocia and is the first longitudinal study to analyse multiple effects and to look beyond the perinatal period. A total of 455 live born Holstein calves (N: No assistance, n=360; FN: Farmer assistance but normally presented calf, n=82; FM: Farmer assistance of malpresented calf, n=13) were followed from birth to first service (heifers) or until leaving the farm (bulls).

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The experience of a difficult birth (dystocia) is traumatic and has adverse effects on the newborn in various species. Despite affecting up to 1 in 3 births in dairy cattle, studies on calves have been mostly limited to the first day of life. The objective of this study was to investigate the effects of dystocia on the survival to calving, growth to weaning, and subsequent fertility as nulliparous animals.

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Congenital muscular dystrophies (CMDs) with associated brain abnormalities are a group of disorders characterized by muscular dystrophy and brain and eye abnormalities that are frequently caused by mutations in known or putative glycotransferases involved in protein O-mannosyl glycosylation. Previous work identified α-dystroglycan as the major substrate for O-mannosylation and its altered glycosylation the major cause of these disorders. However, work from several labs indicated that other proteins in the brain are also O-mannosylated and therefore could contribute to CMD pathology in patients with mutations in the protein O-mannosylation pathway, however few of these proteins have been identified and fully characterized in CMDs.

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Porous platinum nanoparticles provide a route for the development of catalysts that use less platinum without sacrificing catalytic performance. Here, we examine porous platinum nanoparticles using a combination of in situ transmission electron microscopy and calculations based on a first-principles-parametrized thermodynamic model. Our experimental observations show that the initially irregular morphologies of the as-sythesized porous nanoparticles undergo changes at high temperatures to morphologies having faceted external surfaces with voids present in the interior of the particles.

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Objective: To improve awareness of the natural age-related decline in female and male fertility with respect to natural fertility and assisted reproductive technologies (ART) and provide recommendations for their management,and to review investigations in the assessment of ovarian aging.

Options: This guideline reviews options for the assessment of ovarian reserve and fertility treatments using ART with women of advanced reproductive age presenting with infertility.

Outcomes: The outcomes measured are the predictive value of ovarian reserve testing and pregnancy rates with natural and assisted fertility.

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Lamb mortality remains a significant welfare and economic issue for sheep production. Lamb survival is to a degree dependent upon an easy delivery and the expression of appropriate behaviours from both mother and offspring, such as rapid standing, udder seeking and sucking by the lamb. Genetic solutions have the potential to improve birth assistance and lamb behaviour but large amounts of data are needed.

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Ptychographic coherent diffractive imaging (CDI) has been extensively applied using both x rays and electrons. The extension to atomic resolution has been elusive. This Letter demonstrates ptychographic electron diffractive imaging at atomic resolution, permitting identification of structure in a boron nitride helical cone at a resolution of order 1 Å, beyond that of comparative Z-contrast images.

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This work presents a theoretical analysis of image formation in a scanning transmission electron microscope equipped with electron detectors in a plane conjugate to the specimen. This optical geometry encompasses both the three-dimensional imaging technique of scanning confocal electron microscopy (SCEM) and a recently developed atomic resolution imaging technique coined real-space scanning transmission electron microscopy (R-STEM). Image formation in this geometry is considered from the viewpoints of both wave optics and geometric optics, and the validity of the latter is analysed by means of Wigner distributions.

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Without effective pain relief, rubber ring castration of lambs is acutely painful and can also produce chronic pain. The potential of novel, smaller rubber rings to reduce this pain substantially has been investigated. Three groups of eight 2-3 day old lambs, were castrated either with conventional rubber rings (cRR), or novel smaller rubber rings without (nRR) and with local anaesthetic treatment (nRR+La).

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This study assessed the effect of feeding 0.75 energy requirements between Days 1 and 90 of pregnancy on placental development and feto-placental amino acid status on Day 125 of pregnancy in Scottish Blackface and Suffolk ewes carrying a single fetus. Such moderate nutrient restriction did not affect placental size, placentome number or the distribution of placentome types.

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Lunar rocks contain a record of an ancient magnetic field that seems to have persisted for more than 400 million years and which has been attributed to a lunar dynamo. Models of conventional dynamos driven by thermal or compositional convection have had difficulty reproducing the existence and apparently long duration of the lunar dynamo. Here we investigate an alternative mechanism of dynamo generation: continuous mechanical stirring arising from the differential motion, due to Earth-driven precession of the lunar spin axis, between the solid silicate mantle and the liquid core beneath.

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Birth difficulty and poor lamb vigour are significant causes of perinatal lamb mortality. In this study we investigated whether sheep breeds differing in appearance, muscularity and selection history also had differences in dystocia and lamb vigour, and considered some of the factors that may contribute to the variation in these traits. Data were collected at birth from a total of 3252 lambs of two terminal sire breeds selected for lean growth (Suffolk [S], n=500 and Texel [T], n=1207), from a Hill breed (Scottish Blackface [B], n=610), which has been mainly selected for hardiness, and a crossbred (Mule×T [M], n=935) representing a maternal line.

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The neonate's development and survival is dependent upon being vigorous at birth and receiving appropriate maternal care. However, difficulty at delivery can result in less vigorous offspring and maternal care can be altered, probably as a consequence of exhaustion, pain and human intervention. The first 3h after expulsion of the calf were observed continuously from videos following twelve natural calvings and sixteen calvings assisted by farm staff (including four malpresentations) from Holstein cows.

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Two new methods for the measurement of transverse spatial coherence in a transmission electron microscope (TEM) are developed and applied to measure the spatial coherence in a field emission gun TEM. Measurements are made under different illumination and operating conditions, illustrating the effect of these conditions on the spatial coherence. The relative merits and limitations of these methods are discussed and compared, together with the previously described "Ronchigram" method.

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We present an alternative atomic resolution incoherent imaging technique derived from scanning transmission electron microscopy (STEM) using detectors in real space, in contrast to conventional STEM that uses detectors in diffraction space. The images obtained from various specimens have a resolution comparable to conventional high-angle annular dark-field (HAADF) STEM with good contrast, which seems to be very robust with respect to thickness, focus and imaging conditions. The results of the simulations are consistent with the experimental results and support the interpretation of the real-space STEM image contrast as being a result of aberration-induced displacements of the high-angle scattered electrons.

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In this work we investigate methods of statistical processing and background fitting of atomic resolution electron energy loss spectrum image (SI) data. Application of principal component analysis to SI data has been analyzed in terms of the spectral signal-to-noise ratio (SNR) and was found to improve both the spectral SNR and its standard deviation over the SI, though only the latter was found to improve significantly and consistently across all data sets analyzed. The influence of the number of principal components used in the reconstructed data set on the SNR and resultant elemental maps has been analyzed and the experimental results are compared to theoretical calculations.

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It has recently become possible to focus a beam of high-energy electrons to a spot smaller than an atom, with vast potential for the study of condensed matter. We devise an experiment that can image, with subangstrom resolution, the distribution of such an electron beam as it scatters within an atomic lattice. Our experiments reveal the acute sensitivity of the scattered electron distribution to 0.

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Introduction: The purpose of this cross-sectional study was to explore factors associated with oncology patients' decision to bank sperm prior to cancer treatment.

Materials And Methods: Patients who were referred to the oncology sperm banking program between January 2009 and March 2010 were invited to complete an 18-item questionnaire during one of their sperm banking visits.

Results: Of the 157 cancer patients referred to the Mount Sinai Oncology Sperm and Tissue Bank for sperm banking during the 15-month period, 79 questionnaires were returned (50% response rate).

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Human cytochrome P450c21 (steroid 21-hydroxylase, CYP21A2) catalyzes the 21-hydroxylation of progesterone (P4) and its preferred substrate 17α-hydroxyprogestrone (17OHP4). CYP21A2 activities, which are required for cortisol and aldosterone biosynthesis, involve the formation of energetically disfavored primary carbon radicals. Therefore, we hypothesized that the binding of P4 and 17OHP4 to CYP21A2 restricts access of the reactive heme-oxygen complex to the C-21 hydrogen atoms, suppressing oxygenation at kinetically more favorable sites such as C-17 and C-16, which are both hydroxylated by cytochrome P450c17 (CYP17A1).

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The present study investigated whether the genetic growth characteristics (fast or slow growing, lean or fat) of a mother influences her ability to partition nutrients to developing offspring. A total of sixty-one pregnant mice of three selected lines were used: fast-growing, relatively fat (FF, n 19); fast-growing, relatively lean (FL, n 23); and normal growth, relatively lean (NL, n 19). On day 1 of pregnancy, mice were given either ad libitum access to food (control (C): n 32) or pair-fed at 80 % of C intake (restricted (R): n 29).

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This study examined the hypothesis that responses of Scottish Blackface (BF, a hill breed) and Suffolk (SUF, a lowland breed) ewes to undernutrition between d 1 and 90 of pregnancy would differ. Over 2 consecutive breeding seasons, ewes (4 pens/treatment; 15 to 20 ewes/pen) were artificially inseminated and from d 1 to 90 after AI allocated to 0.75 (restricted; RES) or 1.

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The self-assembly of molecularly precise nanostructures is widely expected to form the basis of future high-speed integrated circuits, but the technologies suitable for such circuits are not well understood. In this work, DNA self-assembly is used to create molecular logic circuits that can selectively identify specific biomolecules in solution by encoding the optical response of near-field coupled arrangements of chromophores. The resulting circuits can detect label-free, femtomole quantities of multiple proteins, DNA oligomers, and small fragments of RNA in solution via ensemble optical measurements.

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Two independent strategies are presented for reducing the computation time of multislice simulations of scanning transmission electron microscope (STEM) images: (1) optimal probe sampling, and (2) the use of desktop graphics processing units. The first strategy is applicable to STEM images generated by elastic and/or inelastic scattering, and requires minimal effort for its implementation. Used together, these two strategies can reduce typical computation times from days to hours, allowing practical simulation of STEM images of general atomic structures on a desktop computer.

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The experiment measured lamb responses to supplementation of the pregnant ewe diet with vitamin E above requirement. Crossbred ewes were mated with either Suffolk or Texel rams. Twin-bearing ewes were randomly allocated (approximately 21 months of age at allocation) to one of four treatment groups (20 ewes per group, 10 mated with Suffolk and 10 with Texel rams).

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Purpose: The purpose of this study was to determine whether deliberate increases in speaking rate would serve to decrease the amount of nasality in the speech of severely hearing-impaired individuals.

Method: The participants were 11 severely to profoundly hearing-impaired students, ranging in age from 12 to 19 years (M = 16 years). Each participant provided a baseline speech sample (R1) followed by 3 training sessions during which participants were trained to increase their speaking rate.

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