Top quark spin correlations at hadron colliders: Predictions at next-to-leading order QCD

The collider experiments at the Tevatron and the LHC will allow for detailed investigations of the properties of the top quark. This requires precise predictions of the hadronic production of $t\bar t$ pairs and of their subsequent decays. In this Letter we present for the reactions $p {\bar p}, p p \to t{\bar t} + X \to \ell^+\ell'^-X$ the first calculation of the dilepton angular distribution at next-to-leading order (NLO) in the QCD coupling, keeping the full dependence on the spins of the intermediate $t\bar{t}$ state. The angular distribution reflects the degree of correlation of the $t$ and $\bar t$ spins which we determine for different choices of $t$ and $\bar t$ spin bases. In the case of the Tevatron, the QCD corrections are sizeable, and the distribution is quite sensitive to the parton content of the proton.Comment: 9 pages, 2 figure

Top Quark Pair Production and Decay including Spin Effects at Hadron Colliders: Predictions at NLO QCD

Top quark-antiquark ($t\bar t$) pairs will be produced copiously at the Tevatron collider and in huge numbers at the LHC. This will make possible detailed investigations of the properties and interactions of this quark flavor. The analysis and interpretation of future data requires precise predictions of the hadronic production of $t\bar t$ pairs and of their subsequent decays. In this talk the reactions $p {\bar p}, p p \to t{\bar t} + X \to l^+ l'^- + X$ are considered and results are presented of our calculation of the dilepton angular distribution at next-to-leading order QCD, keeping the full dependence on the spins of the intermediate $t\bar{t}$ state. The angular distribution is determined for different choices of reference axes that can be identified with the $t$ and $\bar t$ spin axes. While the QCD corrections to the leading-order distribution turn out to be small in the case of the LHC, we find them to be sizeable in the case of the Tevatron and find, moreover, the angular distribution to be sensitive to the parton content of the proton.Comment: Talk given at 3rd Circum-Pan-Pacific Symposium on "High Energy Spin Physics", Beijing, China, 8-13, 200

Sharks caught in the protective gill nets off Kwazulu-Natal, South Africa. 9. The spinner shark carcharhinus brevipinna (Müller and Henle)

A total of 2 728 spinner sharks Carcharhinus brevipinna was caught in nets that protect the swimming beaches of KwaZulu-Natal between 1978 and 1997. The species constituted 10.3% of the total shark catch during thatperiod. An average of 136 spinner sharks was caught annually, with no trend in catch rate over the study period. The species was caught throughout the year, predominantly in the south and mainly from February to July. Males matured at approximately 150 cm precaudal length and females at 154 cm. Gonad indices in mature males were highest during December and January and in females during February and March. Mating takes place between January and March. The hepatosomic index of pregnant females was highest at the onset of pregnancy and lowest at parturition. Evidence suggests a two-year reproductive cycle in females, with a gestation period of 13–18 months. The average litter size was nine, with an estimated length at birth of between 50 and 60 cm. Near-term pregnant females were caught mainly in the north, indicating the possibility of a nursery there. Both large and small pregnant females produce pups of the same length, but larger females generally have larger litters.Regional, seasonal and size variations were evident in the diet, with teleosts being the most frequently eaten prey

A Survey on Retrieval of Mathematical Knowledge

We present a short survey of the literature on indexing and retrieval of mathematical knowledge, with pointers to 72 papers and tentative taxonomies of both retrieval problems and recurring techniques.Comment: CICM 2015, 20 page

Virtual Assistants for End-User Development in the Internet of Things

The spread of Virtual Assistants (software and hardware) on the consumer market deeply changed the way Internet of Things (IoT) is implemented and used today. Such devices, and related applications, are becoming more and more integrated within smart environments and this might pave the way to potential new approaches to End-User Development activities, which can be performed in IoT environments. This paper discusses the evolution of the IoT ecosystem definition that has been studied by the authors in the last years

Two-Particle Correlations in Relativistic Heavy-Ion Collisions

Two-particle momentum correlations between pairs of identical particles produced in relativistic heavy-ion reactions can be analyzed to extract the space-time structure of the collision fireball. We review recent progress in the application of this method, based on newly developed theoretical tools and new high-quality data from heavy-ion collision experiments. Implications for our understanding of the collision dynamics and for the search for the quark-gluon plasma are discussed.Comment: 44 pages, LaTeX, 11 Figures, uses special style files (included), prepared for Ann. Rev. Nucl. Part. Sci. 49 (1999). Error in Chapt. 1 corrected and a few references adde

Enhanced recovery protocols for major upper gastrointestinal, liver and pancreatic surgery

BACKGROUND: 'Fast-track surgery' or 'enhanced recovery protocol' or 'fast-track rehabilitation', incorporating one or more elements of preoperative education, pain relief, early mobilisation, enteral nutrition and growth factors, may improve health-related quality of life and reduce length of hospital stay and costs. The role of enhanced recovery protocols in major upper gastrointestinal, liver and pancreatic surgery is unclear. OBJECTIVES: To assess the benefits and harms of enhanced recovery protocols compared with standard care (or usual practice) in major upper gastrointestinal, liver and pancreatic surgery. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL; Cochrane Library; 2015, Issue 3), MEDLINE, EMBASE and Science Citation Index Expanded until March 2015 to identify randomised trials. We also searched the references of included trials to identify further trials. SELECTION CRITERIA: We considered only randomised controlled trials (RCTs) performed in people undergoing major upper gastrointestinal, liver and pancreatic surgery, irrespective of language, blinding or publication status for inclusion in the review. DATA COLLECTION AND ANALYSIS: Two review authors independently identified trials and independently extracted data. We calculated the risk ratio (RR), mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CIs) using both fixed-effect and random-effects models using Review Manager 5, based on available case analysis. MAIN RESULTS: Ten studies met the inclusion criteria for the review, and nine studies provided information on one or more outcomes for the review. A total of 1014 participants were randomly assigned to the enhanced recovery protocol (499 participants) or standard care (515 participants) in the nine RCTs. Most of the trials included low anaesthetic risk participants with high performance status undergoing different upper gastrointestinal, liver and pancreatic surgeries. Eight trials incorporated more than one element of the enhanced recovery protocol. All of the trials were at high risk of bias. The overall quality of evidence was low or very low.None of the trials reported long-term mortality, medium-term health-related quality of life(three months to one year), time to return to normal activity, or time to return to work. The difference between the enhanced recovery protocol and standard care were imprecise for short-term mortality (enhanced recovery protocol: 4/425 (adjusted proportion = 0.6%); standard care: 1/443 (0.2%); seven trials; 868 participants; RR 2.79; 95% CI 0.44 to 17.73; very low quality evidence), proportion of people with serious adverse events (enhanced recovery protocol: 4/157 (adjusted proportion = 0.6%); standard care: 0/184 (0.0%); two trials; 341 participants; RR 5.57; 95% CI 0.68 to 45.89; very low quality evidence), number of serious adverse events (enhanced recovery protocol: 34/421 (8 per 100 participants); standard care: 46/438 (11 per 100 participants); seven trials; 859 participants; rate ratio 0.72; 95% CI 0.45 to 1.13; very low quality evidence), health-related quality of life (four trials; 373 participants; SMD 0.29; 95% CI -0.04 to 0.62; very low quality evidence) and hospital readmissions (enhanced recovery protocol: 14/355 (adjusted proportion = 3.3%); standard care: 9/378 (2.4%); seven trials; 733 participants; RR 1.4; 95% CI 0.69 to 2.87; very low quality evidence). The enhanced recovery protocol group had a lower proportion of people with mild adverse events (enhanced recovery protocol: 31/254 (adjusted proportion = 10.9%); standard care: 51/271 (18.8%); four trials; 525 participants; RR 0.58; 95% CI 0.39 to 0.85; low quality evidence), fewer number of mild adverse events (enhanced recovery protocol: 69/499 (13 per 100 participants); standard care: 128/515 (25 per 100 participants); nine trials; 1014 participants; rate ratio 0.52; 95% CI 0.39 to 0.70; low quality evidence), shorter length of hospital stay (nine trials; 1014 participants; MD -2.19 days; 95% CI -2.53 to -1.85; low quality evidence) and lower costs (four trials; 282 participants; MD USD -6300; 95% CI -8400 to -4200; low quality evidence) than standard care group. AUTHORS' CONCLUSIONS: Based on low quality evidence, enhanced recovery protocols may reduce length of hospital stay and costs (primarily because of reduction in hospital stay) in people undergoing major upper gastrointestinal, liver and pancreatic surgeries. However, the validity of the results is uncertain because of the risk of bias in the trials and the way the outcomes were measured. Future RCTs should be conducted with low risk of bias, and measure clinically important outcomes for including the three months to one year period

Coulomb interactions within Halo Effective Field Theory

I present preliminary results of effective field theory applied to nuclear cluster systems, where Coulomb interactions play a significant role.Comment: Talk given at the 20th European Conference on Few-Body Problems in Physics, Pisa, Italy, September 10-14, 200

The biochemical characteristics of coconut (Cocos nucifera L.) water during germination

The purpose of this study was to determine the biochemical characteristics of coconut water during germination. The three cultivars most used worldwide were studied; West African Tall ‘WAT’, Malaysian Yellow Dwarf ‘MYD’ and improved ‘PB121+’ hybrid. Germinated ‘MYD’ and ‘PB121+’ had the greatest physical characteristic (water weight). As for the chemical parameters, the amounts of total sugar fluctuated from 25.60 mg/ml to 50.85 mg/ml while the amount of ashes and pH varied from 0.25% to 0.47% and 6.36 to 6.97 respectively. Coconut water from the ‘WAT’ and from the ‘PB121+’ hybrid which is richer in sugars and ashes is appropriate for vinegar making. It could be also used as an additive in food for children suffering from mineral deficiencies.Keywords: Biochemical parameter, cultivar, nut, hybri