586 research outputs found
Ricci-flat Metrics with U(1) Action and the Dirichlet Boundary-value Problem in Riemannian Quantum Gravity and Isoperimetric Inequalities
The Dirichlet boundary-value problem and isoperimetric inequalities for
positive definite regular solutions of the vacuum Einstein equations are
studied in arbitrary dimensions for the class of metrics with boundaries
admitting a U(1) action. We show that in the case of non-trivial bundles
Taub-Bolt infillings are double-valued whereas Taub-Nut and Eguchi-Hanson
infillings are unique. In the case of trivial bundles, there are two
Schwarzschild infillings in arbitrary dimensions. The condition of whether a
particular type of filling in is possible can be expressed as a limitation on
squashing through a functional dependence on dimension in each case. The case
of the Eguchi-Hanson metric is solved in arbitrary dimension. The Taub-Nut and
the Taub-Bolt are solved in four dimensions and methods for arbitrary dimension
are delineated. For the case of Schwarzschild, analytic formulae for the two
infilling black hole masses in arbitrary dimension have been obtained. This
should facilitate the study of black hole dynamics/thermodynamics in higher
dimensions. We found that all infilling solutions are convex. Thus convexity of
the boundary does not guarantee uniqueness of the infilling. Isoperimetric
inequalities involving the volume of the boundary and the volume of the
infilling solutions are then investigated. In particular, the analogues of
Minkowski's celebrated inequality in flat space are found and discussed
providing insight into the geometric nature of these Ricci-flat spaces.Comment: 40 pages, 3 figure
Positive words carry less information than negative words
We show that the frequency of word use is not only determined by the word
length \cite{Zipf1935} and the average information content
\cite{Piantadosi2011}, but also by its emotional content. We have analyzed
three established lexica of affective word usage in English, German, and
Spanish, to verify that these lexica have a neutral, unbiased, emotional
content. Taking into account the frequency of word usage, we find that words
with a positive emotional content are more frequently used. This lends support
to Pollyanna hypothesis \cite{Boucher1969} that there should be a positive bias
in human expression. We also find that negative words contain more information
than positive words, as the informativeness of a word increases uniformly with
its valence decrease. Our findings support earlier conjectures about (i) the
relation between word frequency and information content, and (ii) the impact of
positive emotions on communication and social links.Comment: 16 pages, 3 figures, 3 table
Long-Term Efficacy and Safety of Adalimumab in Pediatric Patients with Crohn's Disease
Background: IMAgINE 1 assessed 52-week efficacy and safety of adalimumab in children with moderate to severe Crohn's disease. Long-Term efficacy and safety of adalimumab for patients who entered the IMAgINE 2 extension are reported. Methods: Patients who completed IMAgINE 1 could enroll in IMAgINE 2. Endpoints assessed from weeks 0 to 240 of IMAgINE 2 were Pediatric Crohn's Disease Activity Index remission (Pediatric Crohn's Disease Activity Index ≤ 10) and response (Pediatric Crohn's Disease Activity Index decrease ≥15 from IMAgINE 1 baseline) using observed analysis and hybrid nonresponder imputation (hNRI). For hNRI, discontinued patients were imputed as failures unless they transitioned to commercial adalimumab (with study site closure) or adult care, where last observation was carried forward. Corticosteroid-free remission in patients receiving corticosteroids at IMAgINE 1 baseline, discontinuation of immunomodulators (IMMs) in patients receiving IMMs at IMAgINE 2 baseline, and linear growth improvement were reported as observed. Adverse events were assessed for patients receiving ≥1 adalimumab dose in IMAgINE 1 and 2 through January 2015. Results: Of 100 patients enrolled in IMAgINE 2, 41% and 48% achieved remission and response (hNRI) at IMAgINE 2 week 240. Remission rates were maintained by 45% (30/67, hNRI) of patients who entered IMAgINE 2 in remission. At IMAgINE 2 week 240, 63% (12/19) of patients receiving corticosteroids at IMAgINE 1 baseline achieved corticosteroid-free remission and 30% (6/20) of patients receiving IMMs at IMAgINE 2 baseline discontinued IMMs. Adalimumab treatment led to growth velocity normalization. No new safety signals were identified. Conclusions: Efficacy and safety profiles of prolonged adalimumab treatment in children with Crohn's disease were consistent with IMAgINE 1 and adult Crohn's disease adalimumab trials
First data from DM-Ice17
We report the first analysis of background data from DM-Ice17, a direct-detection dark matter experiment
consisting of 17 kg of NaI(Tl) target material. It was codeployed with IceCube 2457 m deep in the South Pole
glacial ice in December 2010 and is the first such detector operating in the Southern Hemisphere. The
background rate in the 6.5–8.0 keVee region is measured to be 7.9 � 0.4 counts=day=keV=kg. This is
consistent with the expected background from the detector assemblies with negligible contributions from
the surrounding ice. The successful deployment and operation of DM-Ice17 establishes the South Pole ice
as a viable location for future underground, low-background experiments in the Southern Hemisphere. The
detector assembly and deployment are described here, as well as the analysis of the DM-Ice17 backgrounds
based on data from the first two years of operation after commissioning, July 2011–June 2013
Measurement of muon annual modulation and muon-induced phosphorescence in NaI(TI) crystals with DM-Ice17
We report the measurement of muons and muon-induced phosphorescence in DM-Ice17, a NaI(Tl) direct detection dark matter experiment at the South Pole. Muon interactions in the crystal are identified by their observed pulse shape and large energy depositions. The measured muon rate in DM-Ice17 is 2.93±0.04 μ/crystal/day with a modulation amplitude of 12.3±1.7%, consistent with expectation. Following muon interactions, we observe long-lived phosphorescence in the NaI(Tl) crystals with a decay time of 5.5±0.5 s. The prompt energy deposited by a muon is correlated to the amount of delayed phosphorescence, the brightest of which consist of tens of millions of photons. These photons are distributed over tens of seconds with a rate and arrival timing that do not mimic a scintillation signal above 2 keVee. While the properties of phosphorescence vary among individual crystals, the annually modulating signal observed by DAMA cannot be accounted for by phosphorescence with the characteristics observed in DM-Ice17
Body image, body dissatisfaction and weight status in south asian children: a cross-sectional study
Background
Childhood obesity is a continuing problem in the UK and South Asian children represent a group that are particularly vulnerable to its health consequences. The relationship between body dissatisfaction and obesity is well documented in older children and adults, but is less clear in young children, particularly South Asians. A better understanding of this relationship in young South Asian children will inform the design and delivery of obesity intervention programmes. The aim of this study is to describe body image size perception and dissatisfaction, and their relationship to weight status in primary school aged UK South Asian children.
Methods
Objective measures of height and weight were undertaken on 574 predominantly South Asian children aged 5-7 (296 boys and 278 girls). BMI z-scores, and weight status (underweight, healthy weight, overweight or obese) were calculated based on the UK 1990 BMI reference charts. Figure rating scales were used to assess perceived body image size (asking children to identify their perceived body size) and dissatisfaction (difference between perceived current and ideal body size). The relationship between these and weight status were examined using multivariate analyses.
Results
Perceived body image size was positively associated with weight status (partial regression coefficient for overweight/obese vs. non-overweight/obese was 0.63 (95% CI 0.26-0.99) and for BMI z-score was 0.21 (95% CI 0.10-0.31), adjusted for sex, age and ethnicity). Body dissatisfaction was also associated with weight status, with overweight and obese children more likely to select thinner ideal body size than healthy weight children (adjusted partial regression coefficient for overweight/obese vs. non-overweight/obese was 1.47 (95% CI 0.99-1.96) and for BMI z-score was 0.54 (95% CI 0.40-0.67)).
Conclusions
Awareness of body image size and increasing body dissatisfaction with higher weight status is established at a young age in this population. This needs to be considered when designing interventions to reduce obesity in young children, in terms of both benefits and harms
Mothers' perceptions of child weight status and the subsequent weight gain of their children : a population based longitudinal study
BACKGROUND: There is a plethora of cross sectional work on maternal perceptions of child weight status showing that mothers typically do not classify their overweight child as being overweight according to commonly used clinical criteria. Awareness of overweight in their child is regarded as an important prerequisite for mothers to initiate appropriate action. The gap in the literature is determining whether, if mothers do classify their overweight child's weight status correctly, this is associated with a positive outcome for the child's body mass index (BMI) at a later stage. OBJECTIVE: To explore longitudinal perceptions of child weight status from mothers of a contemporary population-based birth cohort (Gateshead Millennium Study) and relationships of these perceptions with future child weight gain. METHODS: Data collected in the same cohort at 7, 12 and 15 years of age: mothers' responses to two items concerning their child's body size; child's and mother's BMI; pubertal maturation; demographic information. RESULTS: Mothers' perceptions of whether their child was overweight did not change markedly over time. Child BMI was the only significant predictor of mothers' classification of overweight status, and it was only at the extreme end of the overweight range and in the obese range that mothers reliably described their child as overweight. Even when mothers did appropriately classify their child as overweight at an earlier stage, this was not related to relatively lower child BMI a few years later. CONCLUSIONS: Mothers tend to classify their child as overweight in only more extreme cases. It is an important finding that no beneficial impact was shown on later child BMI in overweight children whose mothers classified their child's weight status as overweight at an earlier stage.International Journal of Obesity accepted article preview online, 25 January 2017. doi:10.1038/ijo.2017.20
First search for a dark matter annual modulation signal with NaI(Tl) in the Southern Hemisphere by DM-Ice17
We present the first search for a dark matter annual modulation signal in the Southern Hemisphere conducted with NaI(Tl) detectors, performed by the DM-Ice17 experiment. Nuclear recoils from dark matter interactions are expected to yield an annually modulated signal independent of location within the Earth’s hemispheres. DM-Ice17, the first step in the DM-Ice experimental program, consists of 17 kg of NaI(Tl) located at the South Pole under 2200 m.w.e. overburden of Antarctic glacial ice. Taken over 3.6 years for a total exposure of 60.8 kg yr, DM-Ice17 data are consistent with no modulation in the energy range of 4–20 keV, providing the strongest limits on weakly interacting massive particle dark matter from a direct detection experiment located in the Southern Hemisphere. The successful deployment and stable long-term operation of DM-Ice17 establishes the South Pole ice as a viable location for future dark matter searches and in particular for a high-sensitivity NaI(Tl) dark matter experiment to directly test the DAMA/LIBRA claim of the observation of dark matter
Incentive Compatible Reimbursement Schemes for Physicians
We consider physicians with fixed capacity levels. If a physician’s capacity exceeds demand, she may have an incentive to overtreat, i.e., she may provide unnecessary treatments to use up idle capacity. By contrast, with excess demand she may undertreat, i.e., she may not provide necessary treatments since other activities are financially more attractive. We first show that simple fee-for-service reimbursement schemes do not provide proper incentives.
If insurers use, however, fee-for-service schemes with quantity restrictions, they solve the fraudulent physician problem
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