921 research outputs found
Resolving the Tevatron Top Quark Forward-Backward Asymmetry Puzzle: Fully Differential Next-to-Next-to-Leading-Order Calculation
We determine the dominant missing Standard Model (SM) contribution to the top
quark pair forward-backward asymmetry at the Tevatron. Contrary to past
expectations, we find a large, around 27%, shift relative to the well-known
value of the inclusive asymmetry in next-to-leading order (NLO) QCD. Combining
all known Standard Model corrections, we find that AFB^{SM} = 0.095 +- 0.007.
This value is in agreement with the latest D0 measurement [V. M. Abazov et al.
(D0 Collaboration), Phys. Rev. D 90, 072011 (2014)] AFB^{D0} = 0.106+- 0.03 and
about 1.5 sigma below that of CDF [T. Aaltonen et al. (CDF Collaboration),
Phys. Rev. D 87, 092002 (2013)] AFB^{CDF} =0.164 +- 0.047. Our result is
derived from a fully differential calculation of the next-to-next-to leading
order (NNLO) QCD corrections to inclusive top pair production at hadron
colliders and includes - without any approximation - all partonic channels
contributing to this process. This is the first complete fully differential
calculation in NNLO QCD of a two-to-two scattering process with all coloured
partons.Comment: 6 pages, 4 figures. Published journal version: title extended and few
clarifications adde
Further exploration of top pair hadroproduction at NNLO
Top quark pair production is one of the cornerstones of the physics program
at hadron colliders. In this contribution, we further explore the
phenomenological implications of the recent NNLO calculation of the total
inclusive cross-section. We provide a comparison of the scale dependence of the
top pair hadroproduction cross section at different perturbative orders and
study its perturbative convergence (with and without soft-gluon resummation).
We also sketch how the NNLO top quark cross-section could be used to improve
searches of physics beyond the Standard Model.Comment: 8 pages, 8 figures. Contribution to the proceedings of the
twenty-seventh workshop "Les Rencontres de Physique de la Vall\'ee d'Aoste",
held 24 Feb.-02 Mar. 2013 in La Thuile, Aosta Valley, Ital
Seasonal Climatologies and Variability of Eastern Tropical Pacific Surface Waters
Interannual variability caused by the El Nino-Southern Oscillation in the eastern tropical Pacific Ocean (ETP) is analogous to seasonal variability of comparable magnitude.
Climatological spatial patterns and seasonal variability of physical variables that may affect the ETP ecosystem are presented and discussed. Surface temperature, surface
salinity, mixed layer depth, thermocline depth, thermocline strength, and surface dynamic height were derived from bathythermograph, hydrocast, and CTD data. Surface current velocity, divergence, and upwelling velocity were derived from ship drift reports. Surface wind velocity, wind stress, wind divergence, wind stress curl, and Ekman pumping
velocity were derived from gridded pseudostress data obtained from Florida State University. Seasonal maps of these variables, and their deviations from the annual mean, show different patterns of variation in Equatorial (S°S-SON) and Tropical Surface Water (SOlS0N). Seasonal shifts in the trade winds, which affect the strength of equatorial
upwelling and the North Equatorial Countercurrent, cause seasonal variations in most variables. Seasonal and interannual variability of surface temperature, mixed layer depth, thermocline depth and wind stress were quantified. Surface temperature, mixed layer depth and thermocline depth, but not local wind stress, are less variable in Tropical Surface Water than in Equatorial Surface Water. Seasonal and interannual variability are close to equal in most of the ETP, within factors of 2 or less. (PDF file contains 70 pages.
Reconciling Horse Welfare, Worker Safety, and Public Expectations: Horse Event Incident Management Systems in Australia
Human-horse interactions have a rich tradition and can be highly rewarding, particularly within sport and recreation pursuits, but they can also be dangerous or even life-threatening. In parallel, sport and recreation pursuits involving animals, including horses, are facing an increased level of public scrutiny in relation to the use of animals for these purposes. However, the challenge lies with event organisers to reconcile the expectations of the public, the need to meet legal requirements to reduce or eliminate risks to paid and volunteer workers, and address horse welfare. In this article we explore incident management at horse events as an example of a situation where volunteers and horses can be placed at risk during a rescue. We introduce large animal rescue skills as a solution to improving worker safety and improving horse welfare outcomes. Whilst there are government and horse industry initiatives to improve safety and address animal welfare, there remains a pressing need to invest in a strong communication plan which will improve the safety of workplaces in which humans and horses interact
Reconciling Horse Welfare, Worker Safety, and Public Expectations: Horse Event Incident Management Systems in Australia
Human-horse interactions have a rich tradition and can be highly rewarding, particularly within sport and recreation pursuits, but they can also be dangerous or even life-threatening. In parallel, sport and recreation pursuits involving animals, including horses, are facing an increased level of public scrutiny in relation to the use of animals for these purposes. However, the challenge lies with event organisers to reconcile the expectations of the public, the need to meet legal requirements to reduce or eliminate risks to paid and volunteer workers, and address horse welfare. In this article we explore incident management at horse events as an example of a situation where volunteers and horses can be placed at risk during a rescue. We introduce large animal rescue skills as a solution to improving worker safety and improving horse welfare outcomes. Whilst there are government and horse industry initiatives to improve safety and address animal welfare, there remains a pressing need to invest in a strong communication plan which will improve the safety of workplaces in which humans and horses interact
Nonclassical interaction-free detection of objects in a monolithic total-internal-reflection resonator
We show that with an efficiency exceeding 99% one can use a monolithic
total-internal-reflection resonator in order to ascertain the presence of an
object without transferring a quantum of energy to it. We also propose an
experiment on the probabilistic meaning of the electric field that contains
only a very few photons.Comment: RevTeX, 13 pages, 4 ps figures, author's www:
http://m3k.grad.hr/pavici
Bereitstellung von Dendromasse für die Versorgung von Biomassekraftwerken – Analyse am Beispiel des Standorts Elsterwerda
Energieversorgung steht im Spannungsverhältnis zwischen Versorgungssicherheit, Wirtschaftlichkeit, Umweltverträglichkeit und der Notwendigkeit gesellschaftlicher Akzeptanz. Regenerative Energien sind geeignet, die sich perspektivisch öffnende Lücke zwischen der weltweit steigenden Energienachfrage und der unsicheren Expansion des Energieangebots zumindest teilweise zu schließen (BMWI, BMU, 2006). Neben ihrem Beitrag zur Ressourcenschonung und zum Klimaschutz sind sie ein wichtiger Wirtschaftsfaktor (BMU, 2006) und verringern die Abhängigkeit von Energieimporten. Unter den regenerativen Energien zeichnen sich die Bio-Energien auf der Basis nachwachsender Rohstoffe durch ihr großes Potential und die vielfältigen Einsatzmöglichkeiten aus. Sie können für die Erzeugung von Elektrizität, für die Gewinnung von Wärme und für die Produktion von Kraftstoffen genutzt werden. Zudem sind sie kontinuierlich verfügbar und lagerfähig. Langfristig könnte die Nutzung von Biomasse etwa 10 % zur Energiebereitstellung in Deutschland beitragen (vgl. BMU, 2005). Die Voraussetzungen für die Nutzung von Bio-Energien sind sehr günstig. Ihre Umweltverträglichkeit steht außerhalb jeder Diskussion und die gesellschaftliche Akzeptanz ist grundsätzlich hoch. Insbesondere in strukturschwachen Regionen kann die Nutzung eigener Biomasseressourcen einen wichtigen Beitrag zur regionalen Wertschöpfung leisten. Große Wachstumschancen im Bereich der Biomasse werden der Verwendung bisher ungenutzter Holzpotentiale zugesprochen (Auer, 2005). Die Logistik spielt hinsichtlich der Wirtschaftlichkeit der Nutzung von Dendromasse (Energieholz) eine wichtige Rolle. Die Kosten der Bereitstellung übersteigen häufig die des eigentlichen Materialwertes. Umso wichtiger erscheint es, effiziente Bereitstellungskonzepte zu entwickeln
Esophageal granular cell tumor colliding with intramucosal adenocarcinoma: a case report
We report a case of a granular cell tumor colliding with intramucosal adenocarcinoma of the esophagus. A 58-year-old white was found to have a 5 mm nodule in the distal esophagus detected by upper gastrointestinal endoscopy performed as part of the workup of long standing reflux. Endoscopic biopsies revealed intramucosal adenocarcinoma arising in the setting of Barrett’s esophagus. The adenocarcinoma infiltrated a granular cell tumor also present at the nodular site. Endoscopic mucosal resection using Duette band ligation and hot snare electrocautery was performed. Margins were negative for both tumors, and endoscopic surveillance for recurrence is planned
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