7,324 research outputs found

    Is the cosmic microwave background really non-Gaussian?

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    Two recent papers have claimed detection of non-Gaussian features in the COBE DMR sky maps of the cosmic microwave background. We confirm these results, but argue that Gaussianity is still not convincingly ruled out. Since a score of non-Gaussianity tests have now been published, one might expect some mildly significant results even by chance. Moreover, in the case of one measure which yields a detection, a bispectrum statistic, we find that if the non-Gaussian feature is real, it may well be due to detector noise rather than a non-Gaussian sky signal, since a signal-to-noise analysis localizes it to angular scales smaller than the beam. We study its spatial origin in case it is nonetheless due to a sky signal (eg, a cosmic string wake or flat-spectrum foreground contaminant). It appears highly localized in the direction b=39.5, l=257, since removing a mere 5 pixels inside a single COBE beam area centered there makes the effect statistically insignificant. We also test Guassianity with an eigenmode analysis which allows a sky map to be treated as a random number generator. A battery of tests of this generator all yield results consistent with Gaussianity.Comment: Revised to match accepted ApJL version. 4 pages with 2 figs included. Links and color fig at http://www.sns.ias.edu/~max/gaussianity_frames.html or from [email protected]

    Does Unemployment Decrease Cancer Mortality?

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    Recent research indicates that healthier lifestyles during recessions decrease the most common U.S. mortalities, but not cancer. However, they combine specific cancer mortalities with different progressions into one, possibly obscuring cancer’s link to unemployment. This paper estimates a fixed-effects regression model on unemployment and the nine most prevalent cancers between 1988 and 2002 using state-level panel data. Five cancers and total cancer are procyclical, and suggest that unemployment affects both incidence and gestation for some cancers. Consistent with the medical literature, this paper contradicts previous economic research and suggests that behavioral factors significantly impact cancer mortality

    Predictable hydrodynamic conditions explain temporal variations in the density of benthic foraging seabirds in a tidal stream environment

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    VC International Council for the Exploration of the Sea 2016. James J. Waggitt was funded by a NERC Case studentship supported by OpenHydro Ltd and Marine Scotland Science (NE/J500148/1). Shore-based surveys were funded by a NERC (NE/J004340/1) and a Scottish National Heritage (SNH) grant. FVCOM was funded by a NERC grant (NE/J004316/1). The bathymetry data used in hydrodynamic models (HI 1122 Sanday Sound to Westray Firth) was collected by the Maritime and Coastguard Agency (MCA) as part of the UK Civil Hydrography Programme. We wish to thank Christina Bristow, Matthew Finn and Jennifer Norris at the European Marine Energy Centre (EMEC); Ian Davies at Marine Scotland Science; Gail Davoren, Shaun Fraser, Pauline Goulet, Alex Robbins and Helen Wade for invaluable discussions; Thomas Cornulier, Alex Douglas, James Grecian and Samantha Patrick for their help with statistical analysis; and Jenny Campbell and the Cockram family for assistance during fieldwork.Peer reviewedPublisher PD

    Eliminating Barriers: Connecting Seniors to Services in Chittenden County

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    Introduction. Physical activity programs for older adults help to improve physical, social, and emotional health and reduce impairments in activities of daily living1. In Chittenden county, less than 1⁄3 of older adults participate in programs, while 48% report that they would like to exercise more. Our aim was to identify barriers to participation in physical activity programs by older adults in Chittenden county, such as accessibility, transportation, health, affordability, and social isolation, and to identify strategies to overcome these barriers. Methods. 144 paper and electronic surveys were administered in Chittenden County, Vermont to assess use of group programs among older adults aged ≥ 50 years including transportation, motivation, preferences, advertisement, and barriers to access. A focus group explored aspects of ideal group activities for seniors. Results. 87.9% of respondents were active for two or more hours each week, while 46.5% had participated in group programming in the past 6 months. Group par- ticipation was significantly higher among physically active respondents (p=0.020). Motivators for participation in group activity included health benefits, social aspects, and physical activity, while the most cited barrier to attendance was timing conflicts. Respondents received information about programming via word of mouth, email, and online resources. Discussion. Overall, our findings indicate that the majority of respondents are highly active, however, they frequently experience barriers that prevent them from participating in group programming. We recommend offering flexible scheduling, advertising programming via word of mouth and email, and emphasizing program health benefits.https://scholarworks.uvm.edu/comphp_gallery/1260/thumbnail.jp

    Dichotomous development of the gut microbiome in preterm infants.

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    BackgroundPreterm infants are at risk of developing intestinal dysbiosis with an increased proportion of Gammaproteobacteria. In this study, we sought the clinical determinants of the relative abundance of feces-associated Gammaproteobacteria in very low birth weight (VLBW) infants. Fecal microbiome was characterized at ≤ 2 weeks and during the 3rd and 4th weeks after birth, by 16S rRNA amplicon sequencing. Maternal and infant clinical characteristics were extracted from electronic medical records. Data were analyzed by linear mixed modeling and linear regression.ResultsClinical data and fecal microbiome profiles of 45 VLBW infants (gestational age 27.9 ± 2.2 weeks; birth weight 1126 ± 208 g) were studied. Three stool samples were analyzed for each infant at mean postnatal ages of 9.9 ± 3, 20.7 ± 4.1, and 29.4 ± 4.9 days. The average relative abundance of Gammaproteobacteria was 42.5% (0-90%) at ≤ 2 weeks, 69.7% (29.9-86.9%) in the 3rd, and 75.5% (54.5-86%) in the 4th week (p < 0.001). Hierarchical and K-means clustering identified two distinct subgroups: cluster 1 started with comparatively low abundance that increased with time, whereas cluster 2 began with a greater abundance at ≤ 2 weeks (p < 0.001) that decreased over time. Both groups resembled each other by the 3rd week. Single variants of Klebsiella and Staphylococcus described variance in community structure between clusters and were shared between all infants, suggesting a common, hospital-derived source. Fecal Gammaproteobacteria was positively associated with vaginal delivery and antenatal steroids.ConclusionsWe detected a dichotomy in gut microbiome assembly in preterm infants: some preterm infants started with low relative gammaproteobacterial abundance in stool that increased as a function of postnatal age, whereas others began with and maintained high abundance. Vaginal birth and antenatal steroids were identified as predictors of Gammaproteobacteria abundance in the early (≤ 2 weeks) and later (3rd and 4th weeks) stool samples, respectively. These findings are important in understanding the development of the gut microbiome in premature infants

    Phase-coherent lightwave communications with frequency combs

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    Fiber-optical networks are a crucial telecommunication infrastructure in society. Wavelength division multiplexing allows for transmitting parallel data streams over the fiber bandwidth, and coherent detection enables the use of sophisticated modulation formats and electronic compensation of signal impairments. In the future, optical frequency combs may replace multiple lasers used for the different wavelength channels. We demonstrate two novel signal processing schemes that take advantage of the broadband phase coherence of optical frequency combs. This approach allows for a more efficient estimation and compensation of optical phase noise in coherent communication systems, which can significantly simplify the signal processing or increase the transmission performance. With further advances in space division multiplexing and chip-scale frequency comb sources, these findings pave the way for compact energy-efficient optical transceivers.Comment: 17 pages, 9 figure

    Combination methods for HIV prevention in men who have sex with men (MSM)

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    This is the protocol for a review and there is no abstract. The objectives are as follows: This review seeks to examine the effectiveness of prevention interventions for MSM that combine at least two of the three categories of intervention modality (biomedical, behavioural and structural) compared either to other HIV prevention interventions or to minimal/no HIV prevention. Below, descriptions of the criteria that will be used to categorise intervention components are provided under the heading Types of interventions' and the full list of outcomes of interest are provided in the section Types of outcome measures'. All planned comparisons are detailed in the section Data synthesis', followed by the planned variables of interest for subgroup and meta-regression analyses
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