5,832 research outputs found
Next-to-leading order predictions for WW+jet production
In this work we report on a next-to-leading order calculation of WW + jet
production at hadron colliders, with subsequent leptonic decays of the W-bosons
included. The calculation of the one-loop contributions is performed using
generalized unitarity methods in order to derive analytic expressions for the
relevant amplitudes. These amplitudes have been implemented in the parton-level
Monte Carlo generator MCFM, which we use to provide a complete next-to-leading
order calculation. Predictions for total cross-sections, as well as
differential distributions for several key observables, are computed both for
the LHC operating at 14 TeV as well as for a possible future 100 TeV
proton-proton collider.Comment: 14 pages, 7 figures; v2: several references added, 2 typos corrected.
Corresponds to published journal versio
Cloaking and anamorphism for light and mass diffusion
We first review classical results on cloaking and mirage effects for
electromagnetic waves. We then show that transformation optics allows the
masking of objects or produces mirages in diffusive regimes. In order to
achieve this, we consider the equation for diffusive photon density in
transformed coordinates, which is valid for diffusive light in scattering
media. More precisely, generalizing transformations for star domains introduced
in [Diatta and Guenneau, J. Opt. 13, 024012, 2011] for matter waves, we
numerically demonstrate that infinite conducting objects of different shapes
scatter diffusive light in exactly the same way. We also propose a design of
external light-diffusion cloak with spatially varying sign-shifting parameters
that hides a finite size scatterer outside the cloak. We next analyse
non-physical parameter in the transformed Fick's equation derived in [Guenneau
and Puvirajesinghe, R. Soc. Interface 10, 20130106, 2013], and propose to use a
non-linear transform that overcomes this problem. We finally investigate other
form invariant transformed diffusion-like equations in the time domain, and
touch upon conformal mappings and non-Euclidean cloaking applied to diffusion
processes.Comment: 42 pages, Latex, 14 figures. V2: Major changes : some formulas
corrected, some extra cases added, overall length extended from 21 pages (V1)
to 42 pages (present version V2). The last version will appear at Journal of
Optic
A framework and toolkit for the collection and analysis of QoS statistics for voice traffic in Next Generation Networks
The multi-service, multi-architecture nature of NGNs is so complex that the management of services, in addition to networks, emerges as a research challenge. Despite QoS limitations, VoIP (as opposed to VoATM), dominates the Internet and enterprise markets, and is evolving to handle the carrier space. This paper presents a strategy that abstracts QoS away from both VoATM and VoIP in order to manage voice QoS in an NGN environment.Telkom, Siemens, THRI
Shoreline distribution and landscape genetics of bears in a recently deglaciated fjord: Glacier Bay, Alaska
Thesis (M.S.) University of Alaska Fairbanks, 2012To further knowledge of mammalian colonization patterns following deglaciation, I used occupancy modeling to estimate black and brown bear shoreline distribution of Glacier Bay and how these distributions relates to the number years of land exposure and post glacial plant and stream succession. I also conducted microsatellite genetic analysis of brown bear hair and tissue to determine contemporary population structure throughout the park and how it relates to landscape features and surrounding populations. Closed forest cover within 1 km of the study site was a strong positive predictor of black bear occurrence. Brown bears were detected at 100% of sites although their use was highest in recently glaciated and old growth forest areas, and lowest in young forests. The shoreline of Glacier Bay hosts brown bears from three geographically overlapping distinct populations, one of which is likely composed of the original colonizers following glacial retreat that were isolated long enough to undergo genetic drift. The southern portion of Glacier Bay fjord and the Fairweather Mountain range are barriers to dispersal. Evidence of range expansion and recent migration indicate that brown bears are still actively colonizing Glacier Bay
Even a little goes a long way for health? Physical activity, obesity, health-related quality of life and depression
Overweight, obesity and physical inactivity (PI) are of major public health concern globally and associated with multiple adverse health outcomes. Overweight and obese populations experience diminished health-related quality of life (HRQOL) and greater depression symptoms when compared to their normal weight counterparts. Emerging evidence suggests ‘small changes’ in physical activity can produce positive health benefits. The aim of this study was to investigate the effects of a little physical activity across body mass index (BMI) status on HRQOL and depression outcomes. Secondary data analysis was conducted using
the ‘US 2015 Behavioral Risk Factor Surveillance System’ survey. A total of 4,442 participants with complete and valid responses were included in the analysis. A two-way
MANOVA was conducted with BMI (normal weight, overweight, obese) and physical activity (PI, insufficiently active [IA] < 150 min/week) as independent variables and HRQOL-4 and Patient Health Questionnaire-8 (PHQ-8; depression symptoms) as dependent variables. Statistically significant physical activity main effect revealed the IA groups
reported improvements in general health (‘very good’ versus ‘good’), roughly 6.5 days physical health and 3 days mental health, and PHQ-8 (‘none-to-minimal depression’ versus ‘mild depression’) compared to PI groups (p < .001). The overweight groups had larger improvements across dependent variables (except general health) compared to normal weight and obese groups. These findings add support to the growing small changes research, which suggests engaging in a little physical activity can improve health outcomes in overweight and obese populations
The Geographic Distribution of Downburst Frequency across Spaceport Florida
Strong winds from downbursts pose a significant hazard to personnel and launch operations at Cape Canaveral Air Force Station (CCAFS) and NASA Kennedy Space Center (KSC). The CCAFS/KSC complex has a robust mesonet from which an 18 year (1995-2012) warm-season convective wind climatology (WSCWC) was developed (Koermer 2017). While the frequency of downbursts in the area has been determined, the frequency at the individual tower locations has not. The 5-minute peak wind data from the WSCWC was analyzed to determine the geographic distribution of downburst frequency across Spaceport Florida. For this project a downburst was determined by the threshold of peak wind speeds greater than or equal to 35 kt. Data for each individual tower in the mesonet was analyzed to determine the frequency of downburst at that grid point. A distinct pattern emerged that showed downburst maxima near the coast and minima mostly over the mainland. It was hypothesized that Florida flow regimes have a significant influence on thunderstorm initiation and subsequent downbursts (Dinon et al. 2008, McCue et al. 2010, Lupo 2013)
- …