9,461 research outputs found

    Aspects of bovine caesarean section associated with calf mortality, dam survival and subsequent fertility.

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    Bovine caesarean section is a common surgery performed by cattle practitioners yet evidence for justifying many aspects of the surgical procedure is lacking. Between 2001 and 2007, questionnaires were used to gather information on 103 cases of caesarean section performed in one, predominantly dairy, veterinary practice. The results showed that the 14-day cow survival rate was 80.6%, and of those surviving beyond this period, 55.4% carried another calf to term, 27.7% were culled due to infertility and 16.9% were culled due to other reasons. Variables associated with reduced 14-day dam mortality included exteriorising the uterus during surgery (odds ratio [OR] 0.018, 95% confidence interval [CI] 0.0019-0.17, P<0.001), dystocia where fetomaternal disproportion was present (OR 0.090, 95% CI 0.097-0.83, P=0.033), a female calf (OR 0.036, 95% CI 0.0019-0.69, P=0.027), no retained fetal membranes at the first post-operative revisit (OR 0.095, 95% CI 0.013-0.69, P=0.020) and removing abdominal blood clots during surgery (OR 0.10, 95% CI 0.011-0.93, P=0.043). Using a Utrecht suture pattern on the uterus was associated with reduced culling due to infertility (OR 0.12, 95% CI 0.020-0.67, P=0.016). Incision infection was noted in 25.9% of cases where incision status was recorded but this was not associated with the type of local anaesthesia used. Overall calf survival up to the first post-operative visit (24-48 h) was 59.4%, and was associated with shorter duration of surgery, and dystocia due to fetomaternal disproportion. These results offer some evidence-based guidelines to optimise outcomes for this common surgery performed under field conditions

    Activation of pluripotency genes in human fibroblast cells by a novel mRNA based approach

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    Background: Several methods have been used to induce somatic cells to re-enter the pluripotent state. Viral transduction of reprogramming genes yields higher efficiency but involves random insertions of viral sequences into the human genome. Although induced pluripotent stem (iPS) cells can be obtained with the removable PiggyBac transposon system or an episomal system, both approaches still use DNA constructs so that resulting cell lines need to be thoroughly analyzed to confirm they are free of harmful genetic modification. Thus a method to change cell fate without using DNA will be very useful in regenerative medicine. Methodology/Principal Findings: In this study, we synthesized mRNAs encoding OCT4, SOX2, cMYC, KLF4 and SV40 large T (LT) and electroporated them into human fibroblast cells. Upon transfection, fibroblasts expressed these factors at levels comparable to, or higher than those in human embryonic stem (ES) cells. Ectopically expressed OCT4 localized to the cell nucleus within 4 hours after mRNA introduction. Transfecting fibroblasts with a mixture of mRNAs encoding all five factors significantly increased the expression of endogenous OCT4, NANOG, DNMT3 beta, REX1 and SALL4. When such transfected fibroblasts were also exposed to several small molecules (valproic acid, BIX01294 and 5'-aza-2'-deoxycytidine) and cultured in human embryonic stem cell (ES) medium they formed small aggregates positive for alkaline phosphatase activity and OCT4 protein within 30 days. Conclusion/Significance: Our results demonstrate that mRNA transfection can be a useful approach to precisely control the protein expression level and short-term expression of reprogramming factors is sufficient to activate pluripotency genes in differentiated cells

    Geometric quantum computation with NMR

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    The experimental realisation of the basic constituents of quantum information processing devices, namely fault-tolerant quantum logic gates, requires conditional quantum dynamics, in which one subsystem undergoes a coherent evolution that depends on the quantum state of another subsystem. In particular, the subsystem may acquire a conditional phase shift. Here we consider a novel scenario in which this phase is of geometric rather than dynamical origin. As the conditional geometric (Berry) phase depends only on the geometry of the path executed it is resilient to certain types of errors, and offers the potential of an intrinsically fault-tolerant way of performing quantum gates. Nuclear Magnetic Resonance (NMR) has already been used to demonstrate both simple quantum information processing and Berry's phase. Here we report an NMR experiment which implements a conditional Berry phase, and thus a controlled phase shift gate. This constitutes the first elementary geometric quantum computation.Comment: Minor additions at request of referees. 4 pages revtex including 2 figures (1 eps). Nature in pres

    Bulk viscosity of Mixed nucleon-hyperon-quark Matter in Neutron stars

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    We calculate the coefficient of bulk viscosity by considering the non-leptonic weak interactions in the cores of hybrid stars with both hyperons and quarks. We first determine the dependence of the production rate of neutrons on the reaction rate of quarks in the non-leptonic processes, that is Γn=KsΓs+ΓΛ+2ΓΣ\Gamma_{n}=K_{s}\Gamma_{s}+\Gamma_{\Lambda}+2\Gamma_{\Sigma^{-}}. The conversion rate, KsK_{s} in our scenario is a complicated function of baryon number density. We also consider medium effect of quark matter on bulk viscosity. Using these results, we estimate the limiting rotation of the hybrid stars, which may suppress the r-mode instability more effectively. Hybrid stars should be the candidates for the extremely rapid rotators .Comment: This paper contains 17 pages,8 figures and 1 table and is accepted by Monthly Notices of the Royal Astronomical Societ

    Advancing time- and angle-resolved photoemission spectroscopy: The role of ultrafast laser development

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    In the last decade, there has been a proliferation of laser sources for time- and angle-resolved photoemission spectroscopy (TR-ARPES), building on the proven capability of this technique to tackle important scientific questions. In this review, we aim to identify the key motivations and technologies that spurred the development of various laser sources, from frequency up-conversion in nonlinear crystals to high-harmonic generation in gases. We begin with a historical overview of the field in Sec.1, framed by advancements in light source and electron spectrometer technology. An introduction to the fundamental aspects of the photoemission process and the observables that can be studied is given in Sec.2, along with its dependencies on the pump and probe pulse parameters. The technical aspects of TR-ARPES are discussed in Sec.3. Here, experimental limitations such as space charge and resultant trade-offs in source parameters are discussed. Details of various systems and their approach to these trade-offs are given in Sec.4. Within this discussion, we present a survey of TR-ARPES laser sources; a meta-analysis of these source parameters showcases the advancements and trends in modern systems. Lastly, we conclude with a brief discussion of future directions for TR-ARPES and its capabilities in elucidating equilibrium and non-equilibrium observables, as well as its integration with micro-ARPES and spin-resolved ARPES (Sec.5).Comment: 104 pages, 27 figure

    Implementation of a Quantum Search Algorithm on a Nuclear Magnetic Resonance Quantum Computer

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    We demonstrate an implementation of a quantum search algorithm on a two qubit NMR quantum computer based on cytosine.Comment: Six pages, three figure

    The influence of facial femininity on Chinese and White UK women's jealousy

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    It is well established that men report greater jealousy when imagining scenarios in which their romantic partner interacts with men displaying masculine physical characteristics. However, few studies have tested for corresponding effects of sexually dimorphic characteristics on women’s jealousy or tested for these effects in non-Western samples. Thus, we investigated the effects of experimentally manipulated sexually dimorphic face-shape cues on Chinese and White UK women’s jealousy perceptions. Chinese and White UK women both reported greater jealousy when imagining scenarios in which their romantic partner interacted with more feminine women. Both groups of women showed large effects of facial femininity on jealousy perceptions for both Chinese and White UK stimuli. Together, these results suggest that sexually dimorphic facial characteristics influence women’s jealousy and that this effect is not unique to women raised in Western cultures

    Towards a more complete sample of binary central stars of planetary nebulae with Gaia

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    CONTEXT: Many if not most planetary nebulae (PNe) are now thought to be the outcome of binary evolutionary scenarios. However, only a few percent of the PNe in the Milky Way are known to host binary systems. The high-precision repeated observing and long time baseline of Gaia make it well suited for detecting new close binaries through photometric variability. AIMS: We aim to find new close binary central stars of PNe (CSPNe) using data from the Gaia mission, building towards a statistically significant sample of post-common envelope, close binary CSPNe. METHODS: As the vast majority of Gaia sources do not have published epoch photometry, we used the uncertainty in the mean photometry as a proxy for determining the variability of our CSPN sample in the second Gaia data release. We derived a quantity that expresses the significance of the variability, and considered what is necessary to build a clean sample of genuine variable sources. RESULTS: Our selection recovers a large fraction of the known close binary CSPN population, while other CSPNe lying in the same region of the parameter space represent a promising set of targets for ground-based confirmatory follow-up observations. Gaia epoch photometry for four of the newly identified variable sources confirms that the variability is genuine and consistent with binarity

    Peripheral blood eosinophils: a surrogate marker for airway eosinophilia in stable COPD.

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    INTRODUCTION: Sputum eosinophilia occurs in approximately one-third of stable chronic obstructive pulmonary disease (COPD) patients and can predict exacerbation risk and response to corticosteroid treatments. Sputum induction, however, requires expertise, may not always be successful, and does not provide point-of-care results. Easily applicable diagnostic markers that can predict sputum eosinophilia in stable COPD patients have the potential to progress COPD management. This study investigated the correlation and predictive relationship between peripheral blood and sputum eosinophils. It also examined the repeatability of blood eosinophil counts. METHODS: Stable COPD patients (n=141) were classified as eosinophilic or noneosinophilic based on their sputum cell counts (≥3%), and a cross-sectional analysis was conducted comparing their demographics, clinical characteristics, and blood cell counts. Receiver operating characteristic curve analysis was used to assess the predictive ability of blood eosinophils for sputum eosinophilia. Intraclass correlation coefficient was used to examine the repeatability of blood eosinophil counts. RESULTS: Blood eosinophil counts were significantly higher in patients with sputum eosinophilia (n=45) compared to those without (0.3×10(9)/L vs 0.15×10(9)/L; P<0.0001). Blood eosinophils correlated with both the percentage (ρ=0.535; P<0.0001) and number of sputum eosinophils (ρ=0.473; P<0.0001). Absolute blood eosinophil count was predictive of sputum eosinophilia (area under the curve =0.76, 95% confidence interval [CI] =0.67-0.84; P<0.0001). At a threshold of ≥0.3×10(9)/L (specificity =76%, sensitivity =60%, and positive likelihood ratio =2.5), peripheral blood eosinophil counts enabled identification of the presence or absence of sputum eosinophilia in 71% of the cases. A threshold of ≥0.4×10(9)/L had similar classifying ability but better specificity (91.7%) and higher positive likelihood ratio (3.7). In contrast, ≥0.2×10(9)/L offered a better sensitivity (91.1%) for ruling out sputum eosinophilia. There was a good agreement between two measurements of blood eosinophil count over a median of 28 days (intraclass correlation coefficient =0.8; 95% CI =0.66-0.88; P<0.0001). CONCLUSION: Peripheral blood eosinophil counts can help identify the presence or absence of sputum eosinophilia in stable COPD patients with a reasonable degree of accuracy
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