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

Top Physics with the ATLAS detector at LHC

In 2009, the Large Hadron Collider (LHC) will provide first proton-proton collisions. The LHC will be the first top quark factory. 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. 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. Studies performed at 14 TeV in order to estimate the potential of ATLAS to perform an accurate determination of the top quark pair and Single Top production cross section, to measure the top quark mass, the top quark charge, the W and Top polarisations, the Standard Model decay (t-> bW), to search for rare top quark decays and ttbar resonance production are reviewed in this tal

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

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

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

Etiological Profile and Treatment Outcome of Epistaxis at a Tertiary Care Hospital in Northwestern Tanzania: A Prospective Review of 104 Cases.

Epistaxis is the commonest otolaryngological emergency affecting up to 60% of the population in their lifetime, with 6% requiring medical attention. There is paucity of published data regarding the management of epistaxis in Tanzania, especially the study area. This study was conducted to describe the etiological profile and treatment outcome of epistaxis at Bugando Medical Centre, a tertiary care hospital in Northwestern Tanzania. This was a prospective descriptive study of the cases of epistaxis managed at Bugando Medical Centre from January 2008 to December 2010. Data collected were analyzed using SPSS computer software version 15. A total of 104 patients with epistaxis were studied. Males were affected twice more than the females (2.7:1). Their mean age was 32.24 ± 12.54 years (range 4 to 82 years). The modal age group was 31-40 years. The commonest cause of epistaxis was trauma (30.8%) followed by idiopathic (26.9%) and hypertension (17.3%). Anterior nasal bleeding was noted in majority of the patients (88.7%). Non surgical measures such as observation alone (40.4%) and anterior nasal packing (38.5%) were the main intervention methods in 98.1% of cases. Surgical measures mainly intranasal tumor resection was carried out in 1.9% of cases. Arterial ligation and endovascular embolization were not performed. Complication rate was 3.8%. The overall mean of hospital stay was 7.2 ± 1.6 days (range 1 to 24 days). Five patients died giving a mortality rate of 4.8%. Trauma resulting from road traffic crush (RTC) remains the most common etiological factor for epistaxis in our setting. Most cases were successfully managed with conservative (non-surgical) treatment alone and surgical intervention with its potential complications may not be necessary in most cases and should be the last resort. Reducing the incidence of trauma from RTC will reduce the incidence of emergency epistaxis in our centre