2,150 research outputs found

    Stillbirth

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    pages 88-8

    Atmospheric effects on the underground muon intensity

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    It has previously been reported that the barometric pressure coefficient observed for muons at Poatina (vertical absorber depth 357 hg/sq cm) appears to be appreciably higher than would be expected from atmospheric absorption alone. There is a possibility that the effect is due to an upper atmospheric temperature effect arising from an inverse correlation of surface pressure with stratospheric temperature. A new proportional telescope is discussed which has been operating at Poatina since about the beginning of 83 and which has a long term stability suitable for studying variations of atmospheric origin

    Paradigms lost and gained: stakeholder experiences of crisis distance learning during the Covid-19 pandemic

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    The physical distancing requirements designed to slow the contagion of COVID-19 instigated sweeping changes to the education sector. School closures in 193 countries brought significant disruption to education and to the lives of children, parents, and teachers. This study explored the experiences of school stakeholders during this period of crisis distance learning (DL). The perspectives of participants in six discrete focus groups of pupils, parents, and teachers at a private school in Dubai, United Arab Emirates, were subject to thematic analysis. Researchers identified three key themes, including ‘a need for stakeholder support’, ‘curriculum delivery implications’, and ‘educational outcomes of crisis distance learning’. Conclusions and recommendations will be of interest to researchers, teachers, school leaders, and teacher education providers

    Maternal residential pesticide use and risk of childhood leukemia in Costa Rica.

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    Evidence suggests that early-life exposure to pesticides inside the home may be associated with childhood leukemia, however data from Latin American countries are limited. We examined whether self-reported maternal residential pesticide use and nearby pesticide applications-before and after child's birth-were associated with acute lymphoblastic leukemia (ALL) in the Costa Rican Childhood Leukemia Study (CRCLS), a population-based case-control study (2001-2003). Cases (n = 251 ALL) were diagnosed between 1995 and 2000 (age <15 years at diagnosis) and were identified through the Costa Rican Cancer Registry and National Children's Hospital. Population controls (n = 577) were drawn from the National Birth Registry. We fitted unconditional logistic regression models adjusted for child sex, birth year, and socioeconomic status to estimate the exposure-outcome associations and also stratified by child sex. We observed that self-reported maternal insecticide use inside the home in the year before pregnancy, during pregnancy, and while breastfeeding was associated with increased odds of ALL among boys [adjusted Odds Ratio (aOR) = 1.63 (95% confidence interval [95% CI]: 1.05-2.53), 1.75 (1.13-2.73), and 1.75 (1.12-2.73), respectively. We also found evidence of exposure-response relationships between more frequent maternal insecticide use inside the home and increased odds of ALL among boys and girls combined. Maternal report of pesticide applications on farms or companies near the home during pregnancy and at any time period were also associated with ALL. Our study in Costa Rica highlights the need for education to minimize pesticide exposures inside and around the home, particularly during pregnancy and breastfeeding

    Layer by layer - Combining Monads

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    We develop a method to incrementally construct programming languages. Our approach is categorical: each layer of the language is described as a monad. Our method either (i) concretely builds a distributive law between two monads, i.e. layers of the language, which then provides a monad structure to the composition of layers, or (ii) identifies precisely the algebraic obstacles to the existence of a distributive law and gives a best approximant language. The running example will involve three layers: a basic imperative language enriched first by adding non-determinism and then probabilistic choice. The first extension works seamlessly, but the second encounters an obstacle, which results in a best approximant language structurally very similar to the probabilistic network specification language ProbNetKAT

    Far-infrared observations of young clusters embedded in the R Coronae Austrinae and RHO Ophiuchi dark clouds

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    Multicolor far infrared maps in two nearby dark clouds, R Coronae Austrinae and rho Ophiuchi, were made in order to investigate the individual contribution of low mass stars to the energetics and dynamics of the surrounding gas and dust. Emission from cool dust associated with five low mass stars in Cr A and four in rho Oph was detected; their far infrared luminosities range from 2 far infrared luminosities L. up to 40 far infrared luminosities. When an estimate of the bolometric luminosity was possible, it was found that typically more than 50% of the star's energy was radiated longward of 20 micrometers. meaningful limits to the far infrared luminosities of an additional eleven association members in Cr A and two in rho Oph were also obtained. The dust optical depth surrounding the star R Cr A appears to be asymmetric and may control the dynamics of the surrounding molecular gas. The implications of the results for the cloud energetics and star formation efficiency in these two clouds are discussed

    Assessing the effectiveness of traction gels using full-scale and field testing

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    Leaf fall during the autumn season creates low adhesion problems on the railways. Traction gels are used to prevent low adhesion, but very little testing has been carried out to assess their performance. Views on their effectiveness vary and their usage is inconsistent across the UK network as a result. This work developed a range of full-scale laboratory and field tests that can be used to assess traction gel performance. The outcomes can lead to increased industry confidence in their ability to mitigate low adhesion, as well as in future product development. It was shown that as a wheel passes over a puddle of traction gel on a rail head, that the gel element is squeezed away leaving the solid particles behind, pick-up on the wheel of particles was also evident. Traction gels were shown to increase traction in full-scale laboratory friction tests in dry and low adhesion conditions. Field brake tests showed that braking was effective in low adhesion and dry conditions with traction gel applied, matching the laboratory test results. The traction gel was also shown to remove a leaf layer, artificially produced by running a DMU over leaf material on a test track. Subsequent work should validate the results on a working railway line during the autumn season

    Quantifying the Soundscape: How Filters Change Acoustic Indices

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    Monitoring biodiversity can be time consuming and costly. Automated recording units (ARUs) have rapidly emerged as an efficient and cost-effective tool for measuring biodiversity. Acoustic indices are one output from recordings from ARUs that can be quantified to serve as an ecological indicator for biodiversity. However, there is a lack of guidance on what acoustic filters to apply to these indices and when. To address this gap, we collected acoustic data from study locations spanning temperate and tropical forests, agricultural grasslands and croplands, and peri-urban development. We applied filters of 80, 500, 1000, and 2000 Hz to these data when calculating the different indices. In addition, we considered the effect landscape context, road noise, season, and elevation have on seven of the most commonly used acoustic indices with different frequency filters. We found that two indices, Acoustic Diversity Index (ADI) and Acoustic Evenness Index (AEI), were most sensitive to filtering, changing significantly between an 80 and 1000 Hz filter across the different covariates. Acoustic Complexity Index (ACI), however, remained consistent with the different filters. These results suggest that when using acoustic indices, one should be cognizant of the context of the study location and the season of the study period when using ADI and AEI. ACI can be used more generously since it is not as sensitive to filtering. ARUs and acoustic indices are an effective tool for measuring biodiversity, but to ensure proper reporting and ability to compare results across studies, more guidelines on appropriate filtering of acoustic indices should be developed

    The Optical/Near-IR Colors of Broad Absorption Line Quasars, Including the Candidate Radio-Loud BAL Quasar 1556+3517

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    A candidate radio-loud broad absorption line quasar (RLBAL) has been reported by Becker et al. (1997). We present JHK observations of this object and three other radio-detected BALs taken with the new Michigan-Dartmouth-MIT/Ohio State/Aladdin IR Camera (MOSAIC) on the KPNO 4-meter. The candidate RLBAL 1556+3517 has B-K=6.63, redder than all but one or two known z>1 quasars. This strongly suggests the observed continuum of this quasar is reddened by dust. Even when this extreme reddening is taken into account 1556+3517 is still probably radio-loud, although near-IR spectroscopy to measure its Balmer decrement will be needed to verify this. In addition, since it is a flat-spectrum object, VLBI observations to determine the extent (if any) to which beaming affects our estimate of its radio luminosity will be needed before 1556+3517 can be unequivocally declared a radio-loud BAL. We also use our data and data from the literature to show that optically selected BALs as a class have B-K colors consistent with the observed distribution for optically selected quasars as a whole. Thus there is currently no evidence that the tendency of optically selected BALs to be preferentially radio-intermediate (Hooper, Francis, & Impey 1993) is due to extinction artificially lowering estimated BAL optical luminosities. However, as most quasar surveys, both radio and optical, would be insensitive to a population of reddened radio-quiet BALs, the existence of a large population of reddened BALs similar to 1556+3517 cannot yet be ruled out.Comment: Accepted to ApJ Letters; 10 pages including 1 figure and 2 tables. This version somewhat revised from initial submission, with a better figur

    Near Infrared Adaptive Optics Imaging of QSO Host Galaxies

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    We report near-infrared (primarily H-band) adaptive optics (AO) imaging with the Gemini-N and Subaru Telescopes, of a representative sample of 32 nearby (z<0.3) QSOs selected from the Palomar-Green (PG) Bright Quasar Survey (BQS), in order to investigate the properties of the host galaxies. 2D modeling and visual inspection of the images shows that ~36% of the hosts are ellipticals, \~39% contain a prominent disk component, and ~25% are of undetermined type. 30% show obvious signs of disturbance. The mean M_H(host) = -24.82 (2.1L_H*), with a range -23.5 to -26.5 (~0.63 to 10 L_H*). At <L_H*, all hosts have a dominant disk component, while at >2 L_H* most are ellipticals. "Disturbed" hosts are found at all M_H(host), while "strongly disturbed" hosts appear to favor the more luminous hosts. Hosts with prominent disks have less luminous QSOs, while the most luminous QSOs are almost exclusively in ellipticals or in mergers (which presumably shortly will be ellipticals). At z<0.13, where our sample is complete at B-band, we find no clear correlation between M_B(QSO) and M_H(host). However, at z>0.15, the more luminous QSOs (M_B<-24.7), and 4/5 of the radio-loud QSOs, have the most luminous H-band hosts (>7L_H*), most of which are ellipticals. Finally, we find a strong correlation between the "infrared-excess", L_IR/L_BB, of QSOs with host type and degree of disturbance. Disturbed and strongly disturbed hosts and hosts with dominant disks have L_IR/L_BB twice that of non-disturbed and elliptical hosts, respectively. QSOs with "disturbed" and "strongly-disturbed" hosts are also found to have morphologies and mid/far-infrared colors that are similar to what is found for "warm" ultraluminous infrared galaxies, providing further evidence for a possible evolutionary connection between both classes of objects.Comment: 80 pages, accepted for publication in ApJ Supp
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