Measurement of the inclusive jet cross section in ppˉp \bar{p} collisions at s=1.96TeV\sqrt{s}=1.96 {\rm TeV}

We report on a measurement of the inclusive jet cross section in $p \bar{p}$ collisions at a center-of-mass energy $\sqrt s=$1.96 TeV using data collected by the D0 experiment at the Fermilab Tevatron Collider corresponding to an integrated luminosity of 0.70 fb$^{-1}$. The data cover jet transverse momenta from 50 GeV to 600 GeV and jet rapidities in the range -2.4 to 2.4. Detailed studies of correlations between systematic uncertainties in transverse momentum and rapidity are presented, and the cross section measurements are found to be in good agreement with next-to-leading order QCD calculations

Search for Large extra spatial dimensions in the dielectron and diphoton channels in ppˉ\bm{p\bar{p}} collisions at s=\bm{\sqrt{s}=}1.96 TeV

We report on a search for large extra spatial dimensions in the dielectron and diphoton channels using a data sample of 1.05 \invfb of \ppb collisions at a center-of-mass energy of 1.96 TeV collected by the D0 detector at the Fermilab Tevatron Collider. The invariant mass spectrum of the data agrees well with the prediction of the standard model. We find 95% C.L. lower limits on the effective Planck scale between 2.1 and 1.3 TeV for 2 to 7 extra dimensions

Is there H2O stacking disordered ice I in the Solar System?

Water ice exists in large quantities across the Solar System, and it is involved in a wide range of atmospheric and geological processes. Here we focus on the question if stacking disordered ice I (ice Isd) is present in the Solar System. The conditions required to form ice Isd are described and we argue that previous descriptions of ‘cubic ice’ (ice Ic) in the literature may in fact have been concerned with ice Isd. In contrast to the stable hexagonal ice I (ice Ih) and ice Ic, ice Isd is a highly complex material that encompasses a wide range of possible stacking regimes and structures. The most fundamental quantity to describe a given ice Isd sample is its cubicity which reflects the fraction of cubic stacking. Following an introduction into the characterisation techniques used to identify and characterise ice Isd, we discuss the various environments in the Solar System where ice Isd may exist and the relevance its existence may have. This includes the atmospheres of the inner planets, various icy moons as well as comets and other icy objects in the far reaches of the Solar System. The details of the stacking disorder may contain information about the formation and thermal history of ice Isd samples. This offers the exciting prospect of using ice Isd as a marker material for atmospheric and geological processes. The crystallographic space group of ice Isd allows polar structures which could be an important factor for the accretion of ice particles in space. We conclude that ice Isd should exist at several locations in the Solar System and in potentially large quantities. The definitive identification of ice Isd in a natural environment is a next major milestone in our understanding of the importance of water ice across the Solar System

Accuracy of ED Bedside Ultrasound for Identification of gallstones: retrospective analysis of 575 studies

Study Objective: To determine the ability of emergency department (ED) physicians to diagnose cholelithiasis with bedside ultrasound. Methods: ED gallbladder ultrasounds recorded over 37 months were compared to radiology ultrasound interpretation. Results: Of 1,690 ED gallbladder ultrasound scans performed during this period, radiology ultrasound was performed in 575/1690 (34%) cases. ED physician bedside interpretation was 88% sensitive [95% CI, 84-91] and 87% specific [95% CI, 82-91], while positive predictive value (PPV) was 91% [88- 94%] and negative predictive value (NPV) was 83% [78-87%], using radiology interpretation as the criterion reference. Conclusion: ED physician ultrasound of the gallbladder for cholelithiasis is both sensitive and specific

Food system resilience measurement: principles, framework and caveats

There is growing recognition that a better understanding of how food systems respond to crises is critical to build and protect the food security of local populations. But rigorous and reliable methods to measure food system resilience are still missing. In this paper, we build on the current literature to develop an analytical framework aimed at assessing the resilience of food systems at local level. The novel element of the analysis lies in the levels at which resilience is considered. Combining the individual actor level with the notion of 'emergent properties' of food systems, we argue that the overall resilience of food system results from processes that take place – and need to be measured – at both individual and system levels. The framework is structured around three components: (i) the mapping of the actors and the local food system; (ii) the assessment of the resilience of these actors and that of the food system, and (iii) the outcomes of this resilience, assessed in term of local population’s food security. For each of those components, indicators are proposed and the ways to collect them are discussed. The paper then presents the types of analyses that would be necessary to complete to gain a better understanding of the situation regarding the resilience of the local food system under consideration, including the analysis of “positive deviance” among food system actors. The paper concludes with a series of reflections about the caveats and challenges that one may face when attempting to assess food system resilience

Educational Assessment of Medical Student Rotation in Emergency Ultrasound

Background: Medical student ultrasound education is sparse. In 2002, we began the first medical student rotation in emergency ultrasound. Objective: To evaluate if medical students can learn and retain sonographic skills during a two- or four-week elective. Methods: We gave students an exam on the first and last days of the rotation. Six months later, students took the exam a third time. A control group was used for comparison. Results: Over a 19-month period, we enrolled 45 students (25 on the two-week and 20 on the four-week elective). The four-week student post-test score was significantly better than the two- week posttest score (81% vs. 72%, p=0.003). On the six-month exam, the four-week student post-test score was significantly better than the two-week post-test score (77% vs 69%, p=0.008). The control group did not statistically improve. Conclusion: Medical students can learn bedside ultrasound interpretation with clinical integration and retain the knowledge six months later

Optically induced charge-transfer in donor-acceptor-substituted p- and m- C2B10H12 carboranes

Icosahedral carboranes, C2B10H12, have long been considered to be aromatic but the extent of conjugation between these clusters and their substituents is still being debated. m- and p-Carboranes are compared with m- and p-phenylenes as conjugated bridges in optical functional chromophores with a donor and an acceptor as substituents here. The absorption and fluorescence data for both carboranes from experimental techniques (including femtosecond transient absorption, time-resolved fluorescence and broadband fluorescence upconversion) show that the absorption and emission processes involve strong intramolecular charge transfer between the donor and acceptor substituents via the carborane cluster. From quantum chemical calculations on these carborane systems, the charge transfer process depends on the relative torsional angles of the donor and acceptor groups where an overlap between the two frontier orbitals exists in the bridging carborane cluster

Early Radio and X-Ray Observations of the Youngest Nearby Type Ia Supernova PTF 11kly (SN 2011fe)

On 2011 August 24 (UT) the Palomar Transient Factory (PTF) discovered PTF11kly (SN 2011fe), the youngest and most nearby Type Ia supernova (SN Ia) in decades. We followed this event up in the radio (centimeter and millimeter bands) and X-ray bands, starting about a day after the estimated explosion time.We present our analysis of the radio and X-ray observations, yielding the tightest constraints yet placed on the pre-explosion mass-loss rate from the progenitor system of this supernova. We find a robust limit of Ṁ ≾ 10^(−8)(w/100 km s^(−1))M_☉ yr^(−1) from sensitive X-ray non-detections, as well as a similar limit from radio data, which depends, however, on assumptions about microphysical parameters. We discuss our results in the context of single-degenerate models for SNe Ia and find that our observations modestly disfavor symbiotic progenitor models involving a red giant donor, but cannot constrain systems accreting from main-sequence or sub-giant stars, including the popular supersoft channel. In view of the proximity of PTF11kly and the sensitivity of our prompt observations, we would have to wait for a long time (a decade or longer) in order to more meaningfully probe the circumstellar matter of SNe Ia

The Hubble Deep Field North SCUBA Super-map III - Optical and near-infrared properties of submillimetre galaxies

We present a new sub-mm Super-map in the HDF-North region (GOODS-North field), containing 40 statistically robust sources at 850 microns. This map contains additional data, and several new sources, including one of the brightest blank-sky extragalactic sub-mm sources ever detected. We have used the ACS HST images and ground-based near-IR observations from GOODS to develop a systematic approach for counterpart identification. 72 per cent of our sources with optical coverage have a unique optical counterpart using our new techniques for counterpart identification, and an additional 18 per cent have more than one possibility that meet our criteria in the ACS images. We have found a much higher ERO rate than other sub-mm surveys, due to the increased depth in the optical images. The median photometric redshift (and quartile range), from optical and near-infrared data, is 1.7 (1.3-2.5) for the radio-detected sub-mm sources, and rises to 2.3 (1.3-2.7) for the radio-undetected sub-sample. We find interesting correlations between the 850 micron flux and both the i magnitude and the photometric redshift, from which there appears to be an absence of high redshift faint counterparts to the lower flux density SCUBA sources. While the quantitative morphologies span a range of values, in general the sub-mm galaxies show larger sizes and a higher degree of asymmetry than other galaxy populations at the same redshifts.Comment: 20 pages, 11 eps figures. Accepted for publication in MNRAS December 17, 200