10,367 research outputs found

    Compact steep-spectrum sources from the S4 sample

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    We present the results of 5-GHz observations with the VLA A-array of a sample of candidate Compact Steep Spectrum sources (CSSs) selected from the S4 survey. We also estimate the symmetry parameters of high-luminosity CSSs selected from different samples of radio sources, and compare these with the larger sources of similar luminosity to understand their evolution and the consistency of the CSSs with the unified scheme for radio galaxies and quasars. The majority of CSSs are likely to be young sources advancing outwards through a dense asymmetric environment. The radio properties of CSSs are found to be consistent with the unified scheme, in which the axes of the quasars are observed close to the line of sight, while radio galaxies are observed close to the plane of the sky.Comment: accepted for publication in mnras; 8 pages, figure 1 with 21 images, and two additional figures; 2 table

    Platform price parity clauses and market segmentation

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    Price parity clauses (PPCs) are widely adopted by online platforms to force client sellers not to lower their prices elsewhere. We investigate under what conditions online travel agencies (OTAs) decide to apply PPCs, and how this affects hotels' listing decisions on OTAs. We find OTAs adopt PPCs when there is a sufficiently large competitive pressure in the market, either between OTAs, or between hotels (or both). PPCs allow OTAs to charge higher commission fees to hotels, which can respond by delisting from certain OTAs, thereby segmenting the market. We also find that consumers and hotels generally lose out with PPCs

    Perdas de grãos na cultura do milho: pré-colheita, colheita, transporte e armazenamento.

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    Perdas na pre-colheita; Perdas na colheita; Perdas na pos-colheita; Principais pragas dos graos armazenados; Conseguencias do ataque de insetos; Formas de armazenamento e recomendacoes.bitstream/item/37533/1/circ-24.pd

    Impaired Maternal Hemodynamics in Morbidly Obese Women: A Case-control Study.

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    AIM: Maternal obesity is associated with significant pregnancy complications and is a risk factor for the development of hypertensive disorders of pregnancy as well as other adverse outcomes. There are few data regarding the hemodynamic aberrations observed in maternal obesity. The aim of this study was to investigate maternal hemodynamics in morbidly obese pregnant women. METHODS: This was a prospective, case-control study of morbidly obese women (BMI >40 kg/m(2) ) and controls (BMI 20-29.9 kg/m(2) ) at a ratio of one-to-ten. The control population was matched for maternal age and gestational age. BMI was calculated based on maternal height and weight at the time of recruitment to the study, which occurred on the same day as the hemodynamic assessment. Pregnant women in the second or third trimester of pregnancy were included. Women who were found to be hypertensive at any time were excluded from the study. USCOM-1A(®) was used to assess hemodynamic parameters (heart rate, stroke volume, cardiac output and systemic vascular resistance). The parameters were corrected for body surface area (BSA) to provide the stroke volume index (SVI), cardiac index (CI) and systemic vascular resistance index (SVRI). Mann Whitney-U test was used to compare the medians of the hemodynamic variables between the two groups. RESULTS: A total of 30 obese women and 327 controls were recruited. There was no difference in maternal (p = 0.506) or gestational (p = 0.693) age at recruitment between the groups. Mean arterial pressure was higher both at pregnancy booking (90 vs 80 mmHg, p < 0.001) and study recruitment (91 vs 85 mmHg, p < 0.001) in the obese group. Heart rate was higher in the obese group (p = 0.003), however there was no difference in stroke volume (p = 0.271), cardiac output (p = 0.238) or systemic vascular resistance (p = 0.635). Following correction of these parameters for BSA, the SVI (34 vs 45 ml/m(2) , p < 0.001) and CI (2.96 vs 3.64 L/min/m(2) , p < 0.001) were significantly reduced in the obese group, whilst the SVRI was significantly higher (2354 vs 1840 dynes-sec-cm(5) /m(2) , p < 0.001). CONCLUSION: The findings of our study suggest that cardiac function is significantly altered in morbidly obese pregnant women. In order to make appropriate comparisons between individuals, it is imperative that hemodynamic parameters are indexed for BSA - as indeed they are in pediatric cardiology. The novel finding of a reduced CI in morbidly obese pregnant women may explain the predisposition to preeclampsia and other adverse outcomes in this population and warrants further investigation
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