896 research outputs found
the influence of pregnancy and the beginning of lactation on pelage traits in cashmere goats
The aim of this study was to investigate the effect of pregnancy followed by the beginning of lactation on fibre traits incashmere goats. Two groups of cashmere-bearing goats aged between 2-3 years were used. The control group (A) included12 non-lactating, non-pregnant subjects. The experimental group (B) included 12 goats mated during the first weekof June, in order to have pregnancy and the beginning of lactation coincide with the period when cashmere normallygrows. As expected, Liveweight significantly varied in Group B during the last two months of pregnancy, when foetalgrowth reaches its maximum, and following delivery. Hair patch weight, because of the continuous growth of primary andsecondary fibres, increased significantly during the trial (P<0.001). The physiological status considered negatively affected(P<0.05) the total mean growth rate of cashmere fibres and, as a result, their length. Cashmere daily growth ratevalues varied significantly (P<0.05) throughout the experiment, while the effect of the physiological status was notedonly in November – December. Furthermore, this parameter also seems to be influenced by climatic factors and, in particular,environmental temperature, as shown by the negative correlation (r = - 0.28; P<0.05) between cashmere dailygrowth rate and environmental temperature. Guard hair length and growth rate did not differ between the two groups,however, they were influenced by time. Cashmere yield and cashmere production were lower in group B (P<0.05). Nodifferences between groups were observed for cashmere diameter. Overall, pregnancy and the consequent period of lactationnegatively influenced cashmere rather than guard hair fibres. These negative effects were noted in quantitativeterms as yield and production dropped by 37% and 43%, respectively. We hypothesise that the complete overlap of pregnancyand lactation with the period of cashmere growth reduced the number of secondary active follicles and their degreeof activity and caused an increase in competition for the partitioning of nutrients between hair follicles and the graviduterus, first, and then the mammary gland, later
Flow Equations for Non-BPS Extremal Black Holes
We exploit some common features of black hole and domain wall solutions of
(super)gravity theories coupled to scalar fields and construct a class of
stable extremal black holes that are non-BPS, but still can be described by
first-order differential equations. These are driven by a "superpotential'',
which replaces the central charge Z in the usual black hole potential. We
provide a general procedure for finding this class and deriving the associated
"superpotential''. We also identify some other cases which do not belong to
this class, but show a similar behaviour.Comment: LaTeX, 21 pages, 2 figures. v2: reference added, JHEP versio
Leveraging text data for causal inference using electronic health records
Text is a ubiquitous component of medical data, containing valuable
information about patient characteristics and care that are often missing from
structured chart data. Despite this richness, it is rarely used in clinical
research, owing partly to its complexity. Using a large database of patient
records and treatment histories accompanied by extensive notes by attendant
physicians and nurses, we show how text data can be used to support causal
inference with electronic health data in all stages, from conception and design
to analysis and interpretation, with minimal additional effort. We focus on
studies using matching for causal inference. We augment a classic matching
analysis by incorporating text in three ways: by using text to supplement a
multiple imputation procedure, we improve the fidelity of imputed values to
handle missing data; by incorporating text in the matching stage, we strengthen
the plausibility of the matching procedure; and by conditioning on text, we can
estimate easily interpretable text-based heterogeneous treatment effects that
may be stronger than those found across categories of structured covariates.
Using these techniques, we hope to expand the scope of secondary analysis of
clinical data to domains where quantitative data is of poor quality or
nonexistent, but where text is available, such as in developing countries
Simulation of gauge transformations on systems of ultracold atoms
We show that gauge transformations can be simulated on systems of ultracold
atoms. We discuss observables that are invariant under these gauge
transformations and compute them using a tensor network ansatz that escapes the
phase problem. We determine that the Mott-insulator-to-superfluid critical
point is monotonically shifted as the induced magnetic flux increases. This
result is stable against the inclusion of a small amount of entanglement in the
variational ansatz.Comment: 14 pages, 6 figure
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Customized Prediction of Short Length of Stay Following Elective Cardiac Surgery in Elderly Patients Using a Genetic Algorithm
Objective: To develop a customized short LOS (<6 days) prediction model for geriatric patients receiving cardiac surgery, using local data and a computational feature selection algorithm. Design: Utilization of a machine learning algorithm in a prospectively collected STS database consisting of patients who received cardiac surgery between January 2002 and June 2011. Setting: Urban tertiary-care center. Participants: Geriatric patients aged 70 years or older at the time of cardiac surgery. Interventions None. Measurements and Main Results Predefined morbidity and mortality events were collected from the STS database. 23 clinically relevant predictors were investigated for short LOS prediction with a genetic algorithm (GenAlg) in 1426 patients. Due to the absence of an STS model for their particular surgery type, STS risk scores were unavailable for 771 patients. STS prediction achieved an AUC of 0.629 while the GenAlg achieved AUCs of 0.573 (in those with STS scores) and 0.691 (in those without STS scores). Among the patients with STS scores, the GenAlg features significantly associated with shorter LOS were absence of congestive heart failure (CHF) (OR = 0.59, p = 0.04), aortic valve procedure (OR = 1.54, p = 0.04), and shorter cross clamp time (OR = 0.99, p = 0.004). In those without STS prediction, short LOS was significantly correlated with younger age (OR = 0.93, p < 0.001), absence of CHF (OR = 0.53, p = 0.007), no preoperative use of beta blockers (OR = 0.66, p = 0.03), and shorter cross clamp time (OR = 0.99, p < 0.001). Conclusion: While the GenAlg-based models did not outperform STS prediction for patients with STS risk scores, our local-data-driven approach reliably predicted short LOS for cardiac surgery types that do not allow STS risk calculation. We advocate that each institution with sufficient observational data should build their own cardiac surgery risk models
Effect of a moderately hypoenergetic Mediterranean diet and exercise program on body cell mass and cardiovascular risk factors in obese women
Objective: To assess the effects of a moderately hypoenergetic Mediterranean diet (MHMD) and exercise program on body cell mass (BCM) and cardiovascular disease risk factors in obese women. Subjects/Methods: Forty-seven obese women, 39.7 +/- 13.2 years of age, with a body mass index (BMI) 30.7 +/- 6.0 kg/m(2), completed the study. The following were measured at baseline, 2 and 4 months: BCM, BCM index (BCMI), body weight, BMI, fat-free mass (FFM), fat mass (FM), total body water (TBW), extracellular water (ECW) and intracellular water (ICW) using bioelectrical impedance analysis; fasting blood glucose (FBG), serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) concentrations; systolic (SBP) and diastolic (DBP) blood pressure. Results: Body weight, BMI, FM, TC and TG significantly decreased (P<0.001; P<0.002 (TG)) at 2 and 4 months. FFM, TBW, ECW, FBG and DBP significantly decreased at 2 months (P<0.05 (FFM); P<0.001). LDL-C significantly decreased (P<0.001), while HDL-C significantly increased (P<0.002) at 4 months. BCM, BCMI, ICW and SBP remained stable over time. Conclusion: BCM was preserved and cardiovascular disease risk factors improved in obese women placed on a MHMD and exercise program for 4 months
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