Top Physics at the LHC

à paraître dans les proceedings, paru dans POS TOP2006:022,2006In less than two years from now, the Large Hadron Collider (LHC) will provide first proton-proton collisions at sqrt(s) = 14 TeV. The LHC will be a "Top factory" since about 8 millions of top-antitop events will be produced in one year at low luminosity. After the Top quark discovery and first measurements at Tevatron, the LHC will open a new opportunity for precision measurements of the Top quark properties. Prior to data taking, ATLAS and CMS detectors have to be commissioned and precisely calibrated. Further improvements will be achieved with first collisions. Due to the large amount of produced events and clean signal, early Top signals will play an important role in commissioning the detectors. Moreover some of the early LHC physics results could come from Top physics, leading to a major improvement of Top quark understanding and eventually opening a window for physics beyond the standard model

The impact of spikes in handgun acquisitions on firearm-related harms.

BackgroundResearch has documented sharp and short-lived increases in firearm acquisitions immediately following high-profile mass shootings and specific elections, increasing exposure to firearms at the community level. We exploit cross-city variation in the estimated number of excess handgun acquisitions in California following the 2012 presidential election and the Sandy Hook school shooting 5 weeks later to assess whether the additional handguns were associated with increases in the rate of firearm-related harms at the city level.MethodsWe use a two-stage modeling approach. First, we estimate excess handguns as the difference between actual handgun acquisitions, as recorded in California's Dealer Record of Sales, and expected acquisitions, as predicted by a seasonal autoregressive integrated moving-average (SARIMA) time series model. We use Poisson regression models to estimate the effect of city-level excess handgun purchasing on city-level changes in rates of firearm mortality and injury.ResultsWe estimate there were 36,142 excess handguns acquired in California in the 11 weeks following the election (95% prediction interval: 22,780 to 49,505); the Sandy Hook shooting occurred in week 6. We find city-level purchasing spikes were associated with higher rates of firearm injury in the 52 weeks post-election: a relative rate of 1.044 firearm injuries for each excess handgun per 1,000 people (95% CI: 1.000 to 1.089). This amounts to approximately 290 (95% CI: 0 to 616) additional firearm injuries (roughly a 4% increase) in California over the year. We do not detect statistically significant associations for shorter time windows or for firearm mortality.ConclusionThis study provides evidence for an association between excess handgun acquisitions following high-profile events and firearm injury at the community level. This suggests that even marginal increases in handgun prevalence may be impactful

Near-universal hospitalization of US emergency department patients with cancer and febrile neutropenia

IMPORTANCE: Febrile neutropenia (FN) is the most common oncologic emergency and is among the most deadly. Guidelines recommend risk stratification and outpatient management of both pediatric and adult FN patients deemed to be at low risk of complications or mortality, but our prior single-center research demonstrated that the vast majority (95%) are hospitalized. OBJECTIVE: From a nationwide perspective, to determine the proportion of cancer patients of all ages hospitalized after an emergency department (ED) visit for FN, and to analyze variability in hospitalization rates. Our a priori hypothesis was that >90% of US cancer-associated ED FN visits would end in hospitalization. DESIGN: Analysis of data from the Nationwide Emergency Department Sample, 2006-2014. SETTING: Stratified probability sample of all US ED visits. PARTICIPANTS: Inclusion criteria were: (1) Clinical Classification Software code indicating cancer, (2) diagnostic code indicating fever, and (3) diagnostic code indicating neutropenia. We excluded visits ending in transfer. EXPOSURE: The hospital at which the visit took place. MAIN OUTCOMES AND MEASURES: Our main outcome is the proportion of ED FN visits ending in hospitalization, with an a priori hypothesis of >90%. Our secondary outcomes are: (a) hospitalization rates among subsets, and (b) proportion of variability in the hospitalization rate attributable to which hospital the patient visited, as measured by the intra-class correlation coefficient (ICC). RESULTS: Of 348,868 visits selected to be representative of all US ED visits, 94% ended in hospitalization (95% Confidence Interval [CI] 93-94%). Each additional decade of age conferred 1.23x increased odds of hospitalization. Those with private (92%), self-pay (92%), and other (93%) insurance were less likely to be hospitalized than those with public insurance (95%, odds ratios [OR] 0.74-0.76). Hospitalization was least likely at non-metropolitan hospitals (84%, OR 0.15 relative to metropolitan teaching hospitals), and was also less likely at metropolitan non-teaching hospitals (94%, OR 0.64 relative to metropolitan teaching hospitals). The ICC adjusted for hospital random effects and patient and hospital characteristics was 26% (95%CI 23-29%), indicating that 26% of the variability in hospitalization rate was attributable to which hospital the patient visited. CONCLUSIONS AND RELEVANCE: Nearly all cancer-associated ED FN visits in the US end in hospitalization. Inter-hospital variation in hospitalization practices explains 26% of the limited variability in hospitalization decisions. Simple, objective tools are needed to improve risk stratification for ED FN patients

Estimates of Electronic Medical Records in U.S. Emergency Departments

Background: Policymakers advocate universal electronic medical records (EMRs) and propose incentives for “meaningful use” of EMRs. Though emergency departments (EDs) are particularly sensitive to the benefits and unintended consequences of EMR adoption, surveillance has been limited. We analyze data from a nationally representative sample of US EDs to ascertain the adoption of various EMR functionalities. Methodology/Principal: Findings We analyzed data from the National Hospital Ambulatory Medical Care Survey, after pooling data from 2005 and 2006, reporting proportions with 95% confidence intervals (95% CI). In addition to reporting adoption of various EMR functionalities, we used logistic regression to ascertain patient and hospital characteristics predicting “meaningful use,” defined as a “basic” system (managing demographic information, computerized provider order entry, and lab and imaging results). We found that 46% (95% CI 39–53%) of US EDs reported having adopted EMRs. Computerized provider order entry was present in 21% (95% CI 16–27%), and only 15% (95% CI 10–20%) had warnings for drug interactions or contraindications. The “basic” definition of “meaningful use” was met by 17% (95% CI 13–21%) of EDs. Rural EDs were substantially less likely to have a “basic” EMR system than urban EDs (odds ratio 0.19, 95% CI 0.06–0.57, p = 0.003), and Midwestern (odds ratio 0.37, 95% CI 0.16–0.84, p = 0.018) and Southern (odds ratio 0.47, 95% CI 0.26–0.84, p = 0.011) EDs were substantially less likely than Northeastern EDs to have a “basic” system. Conclusions/Significance: EMRs are becoming more prevalent in US EDs, though only a minority use EMRs in a “meaningful” way, no matter how “meaningful” is defined. Rural EDs are less likely to have an EMR than metropolitan EDs, and Midwestern and Southern EDs are less likely to have an EMR than Northeastern EDs. We discuss the nuances of how to define “meaningful use,” and the importance of considering not only adoption, but also full implementation and consequences

Dietary Advice Provided to Those Undergoing Pelvic Radiotherapy

In those receiving radiotherapy for pelvic cancers, up to 80% develop gastrointestinal symptoms, with dietary interventions recommended to reduce these symptoms. However, research outlining the current dietary support provided to patients undergoing radiotherapy for pelvic cancer is lacking. To identify the gastrointestinal symptoms experienced by those undergoing pelvic radiotherapy and to identify the dietary support provided to these patients. A service evaluation was undertaken in one NHS Trust hospital whereby patients undergoing radical pelvic radiotherapy during a 15-week recruitment period were invited to complete an anonymous questionnaire. Participants were recruited using purposive sampling and the data were analysed descriptively using SPSS. In total, 31 patients responded achieving a response rate of 48%. The most frequent reported gastrointestinal symptoms were gas and flatulence followed by diarrhoea, nausea and abdominal pain. The main dietary changes implemented by the respondents and recommended by health care professionals included reducing fibre intake, reducing certain vegetables, reducing caffeine and increasing water. The results illustrate the impact of gastrointestinal side effects on patients’ dietary intake. The results highlight that nutritional guidance need to be standardised, especially for the management of diarrhoea and gas and flatulence as these were the most common occurring side effects. With radiographers most frequently giving nutritional advice they must be provided with guidance to support those undergoing pelvic radiotherapy

Investigation of top mass measurements with the ATLAS detector at LHC

Several methods for the determination of the mass of the top quark with the ATLAS detector at the LHC are presented. All dominant decay channels of the top quark can be explored. The measurements are in most cases dominated by systematic uncertainties. New methods have been developed to control those related to the detector. The results indicate that a total error on the top mass at the level of 1 GeV should be achievable.Comment: 47 pages, 40 figure