The spin density matrix of top quark pairs produced in electron-positron annihilation including QCD radiative corrections

We calculate the spin density matrix of top quark pairs for the reaction $e^+e^-\to t\bar{t}X$ to order $\alpha_s$. As an application we show next-to-leading order results for a variety of spin observables for the $t\bar{t}$ system. These include the top quark and antiquark polarizations and $t\bar{t}$ spin-spin correlations as a function of the center-of-mass energy and of the top quark scattering angle for arbitrary longitudinal polarization of the electron/positron beam.Comment: 26 pages, 13 Postscript figures, uses REVTE

Polarization and spin correlations of top quarks at a future e+ e- linear collider

We discuss the polarization and spin correlations of top quarks produced above threshold at a future linear collider, including QCD radiative corrections.Comment: 11 pages (LaTeX), 16 Postscript figure. Contribution to the International Workshop on "Symmetry and Spin", PRAHA-SPIN99, Prague, Czech Republic, September 5 -12, 199

Exploring local quantum many-body relaxation by atoms in optical superlattices

We establish a setting - atoms in optical superlattices with period 2 - in which one can experimentally probe signatures of the process of local relaxation and apparent thermalization in non-equilibrium dynamics without the need of addressing single sites. This opens up a way to explore the convergence of subsystems to maximum entropy states in quenched quantum many-body systems with present technology. Remarkably, the emergence of thermal states does not follow from a coupling to an environment, but is a result of the complex non-equilibrium dynamics in closed systems. We explore ways of measuring the relevant signatures of thermalization in this analogue quantum simulation of a relaxation process, exploiting the possibilities offered by optical superlattices.Comment: 4 pages, 3 figures, version to published in Physical Review Letter

Population Trends of Bighorn Sheep and Mountain Goats in the Greater Yellowstone Area

Bighorn sheep (Ovis canadensis) and mountain goats (Oreamnos americanus) are important components of the large mammal community in the Greater Yellowstone Area (GYA) and are of considerable public interest. However, foundational ecological research concerning these species is limited. We analyzed historic bighorn sheep and mountain goat population counts collected by management biologists using ln-linear regression to estimate herd growth rates (?). The analyzed dataset consisted of 538 bighorn sheep counts since 1971 and 120 mountain goat counts since 1966. Most mountain goat count units experienced a positive growth rate and increased their distributions over recent decades. Bighorn sheep growth rates were more variable among the 26 recognized herd units in the GYA. We used the historic count data to evaluate the hypothesis that sympatry of non-native mountain goats with bighorn sheep adversely affected bighorn sheep populations. This was accomplished by comparing the growth rates of sympatric herds with that of allopatric herds. There was no evidence that sympatric herd growth rates were significantly lower than allopatric herd growth rates. We caution, however, that many counts in consecutive years suggested larger changes in abundance than what would be reasonable to expect from biological processes. We suspect that variability in counts likely reflects varying detection probability and the overall difficulty of counting mountain ungulates. Therefore, conclusions derived from these data should be further evaluated with more detailed demographic studies in the future

Bighorn Sheep Movements and Mineral Lick Use in Waterton-Glacier International Peace Park (Poster)

This study used bighorn sheep telemetry data collected in Glacier National Park, Waterton Lakes National Park, and the Blackfeet Reservation to examine bighorn sheep movements and use of known mineral licks.  Over 168,400 GPS locations were collected between 2002 and 2011 on 97 bighorn sheep individuals from 17 different social groups.  We examined the proximity of bighorn sheep telemetry data to 32 known mineral lick locations to describe timing and frequency of mineral lick use.  Fifty individuals had locations near known mineral licks, and most mineral lick visits took place between May and August.  We compared movements towards known mineral lick locations with general bighorn sheep movements.  After estimating bighorn sheep kernel home ranges, we evaluated how movement towards the lick, timing, and frequency of use varied depending on location of the lick relative to sheep home ranges.  We conducted a k-means cluster analysis of movement characteristics to identify potential locations of unknown mineral licks and movement pinch points.  We will discuss options for using these locations to monitor bighorn sheep health and population size

Technology for large-scale translation of clinical practice guidelines : a pilot study of the performance of a hybrid human and computer-assisted approach

Background: The construction of EBMPracticeNet, a national electronic point-of-care information platform in Belgium, was initiated in 2011 to optimize quality of care by promoting evidence-based decision-making. The project involved, among other tasks, the translation of 940 EBM Guidelines of Duodecim Medical Publications from English into Dutch and French. Considering the scale of the translation process, it was decided to make use of computer-aided translation performed by certificated translators with limited expertise in medical translation. Our consortium used a hybrid approach, involving a human translator supported by a translation memory (using SDL Trados Studio), terminology recognition (using SDL Multiterm termbases) from medical termbases and support from online machine translation. This has resulted in a validated translation memory which is now in use for the translation of new and updated guidelines. Objective: The objective of this study was to evaluate the performance of the hybrid human and computer-assisted approach in comparison with translation unsupported by translation memory and terminology recognition. A comparison was also made with the translation efficiency of an expert medical translator. Methods: We conducted a pilot trial in which two sets of 30 new and 30 updated guidelines were randomized to one of three groups. Comparable guidelines were translated (a) by certificated junior translators without medical specialization using the hybrid method (b) by an experienced medical translator without this support and (c) by the same junior translators without the support of the validated translation memory. A medical proofreader who was blinded for the translation procedure, evaluated the translated guidelines for acceptability and adequacy. Translation speed was measured by recording translation and post-editing time. The Human Translation Edit Rate was calculated as a metric to evaluate the quality of the translation. A further evaluation was made of translation acceptability and adequacy. Results: The average number of words per guideline was 1,195 and the mean total translation time was 100.2 min/1,000 words. No meaningful differences were found in the translation speed for new guidelines. The translation of updated guidelines was 59 min/1,000 words faster (95% CI 2-115; P=.044) in the computer-aided group. Revisions due to terminology accounted for one third of the overall revisions by the medical proofreader. Conclusions: Use of the hybrid human and computer-aided translation by a non-expert translator makes the translation of updates of clinical practice guidelines faster and cheaper because of the benefits of translation memory. For the translation of new guidelines there was no apparent benefit in comparison with the efficiency of translation unsupported by translation memory (whether by an expert or non-expert translator

Colour stability and water-holding capacity of M. longissimus and carcass characteristics in fallow deer (Dama dama) grazed on natural pasture or fed barley

The effects of feeding regimen on carcass characteristics, meat colour and water-holding capacity of M. longissimus were studied in 24 female fallow deer (Dama dama). All animals were farm raised; twelve were grazed on pasture and twelve were fed barley and a small amount of hay prior to slaughter. The animals were slaughtered at two occasions (during the Southern Hemisphere spring); after 19 weeks of feeding (n=12; 6 grazing and 6 barley fed animals; group 1) and after 24 weeks of feeding (n=12; 6 grazing and 6 barley fed animals; group 2). The barley/hay-fed deer had significantly higher body condition scores and carcass weights than the pasture raised group. No difference in meat ultimate pH values between the treatment groups was recorded. The meat from the pasture raised deer had significantly longer colour display life after 2 and 3 weeks of refrigerated storage (+ 2.0 ºC) in vacuum bags. There was no difference in drip loss between the two treatment groups. However, significantly lower drip losses were found in meat from the animals in group 2 compared with the ones in group 1 (P ≤ 0.001). It was concluded that the feeding regimen of the animals is an important factor that contributes to the variation in quality of fresh chilled deer meat (venison), mainly the colour stability and display life of vacuum packaged meat.Abstract in Swedish / Sammanfattning: I denna undersökning ingick 24 dovhjortshindar (Dama dama) för att studera effekterna av olika typer av foder (bete och korn) på slaktkroppskvalitet samt färg och vattenhållande förmåga i köttet (M. longissimus). Alla djur var uppfödda på en hjortfarm, 12 betade gräs och 12 utfodrades med korn och en liten mängd hö före slakt. Djuren slaktades vid två olika tillfällen (under våren på det södra halvklotet); efter 19 veckors utfodring (n=12; 6 betesdjur och 6 kornfodrade djur; grupp 1) och efter 24 veckors utfodring (n=12; 6 betesdjur och 6 kornfodrade djur; grupp 2). De dovhjortar som utfodrats med korn och hö var i bättre kondition och hade högre slaktvikter jämfört med de djur som betat gräs. Ingen skillnad i köttets pH-värde mellan de två utfodringsgrupperna kunde dock påvisas. Köttet från de betande dovhjortarna hade bättre färgstabilitet efter lagring i 2 och 3 veckor (+ 2.0 ºC) i vakuumförpackning. Det fanns ingen skillnad mellan kött från betande och korn/hö-utfodrade djur i vattenhållande förmåga. Däremot hade kött från djur i grupp 2 (slaktade efter 24 veckors utfodring) bättre vattenhållande förmåga jämfört med grupp 1 (P ≤ 0.001). Vi kunde konstatera att de olika fodertyperna påverkade kvaliteten hos färskt kyllagrat kött, framförallt färgstabiliteten hos vakuumförpackat kött

Particle number conservation in quantum many-body simulations with matrix product operators

Incorporating conservation laws explicitly into matrix product states (MPS) has proven to make numerical simulations of quantum many-body systems much less resources consuming. We will discuss here, to what extent this concept can be used in simulation where the dynamically evolving entities are matrix product operators (MPO). Quite counter-intuitively the expectation of gaining in speed by sacrificing information about all but a single symmetry sector is not in all cases fulfilled. It turns out that in this case often the entanglement imposed by the global constraint of fixed particle number is the limiting factor.Comment: minor changes, 18 pages, 5 figure

An Initial Assessment of the Potential of Genomic Analysis to Help Inform Bighorn Sheep Management

Genetic research may be a useful approach for understanding factors that could impact productivity and restoration of bighorn sheep (Ovis canadensis) herds.  For example, genetic consequences of inbreeding in small populations can impact recruitment and local adaptations can influence translocation success.  This modest pilot study quantified genetic attributes of bighorn sheep populations with a range of different herd histories in Montana and Wyoming to investigate genetic similarity and differences, genetic heterogeneity and genetic distance.  Employing an Ovine array containing about 700,000 single nucleotide polymorphisms (SNPs) with approximately 24,000 markers that are informative for Rocky Mountain bighorn sheep, we used whole genome genotyping to analyze genetic material.  This technique represents a significant advancement in genetic analysis of bighorn sheep, as most previous studies have used microsatellites and less than 200 genetic markers.  We analyzed approximately fifteen individuals from each of four different populations that we predicted would differ in genetic characteristics, due to population dissimilarities that potentially impacted their genetics, including origin (native/reintroduced), population size, bottleneck history, degree of connectivity, and augmentation history.  We selected four populations that provided a spectrum of these herd attributes, including the Tendoys, Stillwater and Glacier National Park in Montana and the northeastern Greater Yellowstone Area in Wyoming.  We present the results of this effort and examine expected and observed heterogeneity and genetic distance estimates to evaluate the potential for links between genetics and herd demography.  We discuss the utility of genetic analyses in improving knowledge of bighorn sheep populations and potential implications for bighorn sheep management