831 research outputs found
A robust tracking system for low frame rate video
Tracking in low frame rate (LFR) videos is one of the most important problems in the tracking literature. Most existing approaches treat LFR video tracking as an abrupt motion tracking problem. However, in LFR video tracking applications, LFR not only causes abrupt motions, but also large appearance changes of objects because the objects’ poses and the illumination may undergo large changes from one frame to the next. This adds extra difficulties to LFR video tracking. In this paper, we propose a robust and general tracking system for LFR videos. The tracking system consists of four major parts: dominant color-spatial based object representation, bin-ratio based similarity measure, annealed particle swarm optimization (PSO) based searching, and an integral image based parameter calculation. The first two parts are combined to provide a good solution to the appearance changes, and the abrupt motion is effectively captured by the annealed PSO based searching. Moreover, an integral image of model parameters is constructed, which provides a look-up table for parameters calculation. This greatly reduces the computational load. Experimental results demonstrate that the proposed tracking system can effectively tackle the difficulties caused by LFR
Need for criteria for the diagnosis and severity assessment of acute cholangitis and cholecystitis: Tokyo Guidelines
The Tokyo Guidelines formulate clinical guidance for healthcare providers regarding the diagnosis, severity assessment, and treatment of acute cholangitis and acute cholecystitis. The Guidelines were developed through a comprehensive literature search and selection of evidence. Recommendations were based on the strength and quality of evidence. Expert consensus opinion was used to enhance or formulate important areas where data were insufficient. A working group, composed of gastroenterologists and surgeons with expertise in biliary tract surgery, supplemented with physicians in critical care medicine, epidemiology, and laboratory medicine, was selected to formulate draft guidelines. Several other groups (including members of the Japanese Society for Abdominal Emergency Medicine, the Japan Biliary Association, and the Japanese Society of Hepato-Biliary-Pancreatic Surgery) have reviewed and revised the draft guidelines. To build a global consensus on the management of acute biliary infection, an international expert panel, representing experts in this area, was established. Between April 1 and 2, 2006, an International Consensus Meeting on acute biliary infections was held in Tokyo. A consensus was determined based on best available scientific evidence and discussion by the panel of experts. This report describes the highlights of the Tokyo International Consensus Meeting in 2006. Some important areas focused on at the meeting include proposals for internationally accepted diagnostic criteria and severity assessment for both clinical and research purposes
Modern management of pyogenic hepatic abscess: a case series and review of the literature
<p>Abstract</p> <p>Background</p> <p>Pyogenic hepatic abscesses are relatively rare, though untreated are uniformly fatal. A recent paradigm shift in the management of liver abscesses, facilitated by advances in diagnostic and interventional radiology, has decreased mortality rates. The aim of this study was to review our experience in managing pyogenic liver abscess, review the literature in this field, and propose guidelines to aid in the current management of this complex disease.</p> <p>Methods</p> <p>Demographic and clinical details of all patients admitted to a single institution with liver abscess over a 5 year period were reviewed. Clinical presentation, aetiology, diagnostic work-up, treatment, morbidity and mortality data were collated.</p> <p>Results</p> <p>Over a 5 year period 11 patients presented to a single institution with pyogenic hepatic abscess (55% males, mean age 60.3 years). Common clinical features at presentation were non-specific constitutional symptoms and signs. Aetiology was predominantly gallstones (45%) or diverticular disease (27%). In addition to empiric antimicrobial therapy, all patients underwent radiologically guided percutaneous drainage of the liver abscess at diagnosis and only 2 patients required surgical intervention, including one 16-year old female who underwent hemi-hepatectomy for a complex and rare Actinomycotic abscess. There were no mortalities after minimum follow-up of one year.</p> <p>Conclusions</p> <p>Pyogenic liver abscesses are uncommon, and mortality has decreased over the last two decades. Antimicrobial therapy and radiological intervention form the mainstay of modern treatment. Surgical intervention should be considered for patients with large, complex, septated or multiple abscesses, underlying disease or in whom percutaneous drainage has failed.</p
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector
The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV
Search for pair-produced long-lived neutral particles decaying to jets in the ATLAS hadronic calorimeter in ppcollisions at √s=8TeV
The ATLAS detector at the Large Hadron Collider at CERN is used to search for the decay of a scalar boson to a pair of long-lived particles, neutral under the Standard Model gauge group, in 20.3fb−1of data collected in proton–proton collisions at √s=8TeV. This search is sensitive to long-lived particles that decay to Standard Model particles producing jets at the outer edge of the ATLAS electromagnetic calorimeter or inside the hadronic calorimeter. No significant excess of events is observed. Limits are reported on the product of the scalar boson production cross section times branching ratio into long-lived neutral particles as a function of the proper lifetime of the particles. Limits are reported for boson masses from 100 GeVto 900 GeV, and a long-lived neutral particle mass from 10 GeVto 150 GeV
Risk of hyperkalemia in patients with moderate chronic kidney disease initiating angiotensin converting enzyme inhibitors or angiotensin receptor blockers : a randomized study
Background: Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers are renoprotective but both may increase serum potassium concentrations in patients with chronic kidney disease (CKD). The proportion of affected patients, the optimum follow-up period and whether there are differences between drugs in the development of this complication remain to be scertained. Methods: In a randomized, double-blind, phase IV, controlled, crossover study we recruited 30 patients with stage 3 CKD under restrictive eligibility criteria and strict dietary control. With the exception of withdrawals, each patient was treated with olmesartan and enalapril separately for 3 months each, with a 1-week wash-out period between treatments. Patients were clinically assessed on 10 occasions via measurements of serum and urine samples. We used the Cochran-Mantel-Haenszel statistics for comparison of categorical data between groups. Comparisons were also made using independent two-sample t-tests and Welch's t-test. Analysis of variance (ANOVA) was performed when necessary. We used either a Mann-Whitney or Kruskal-Wallis test if the distribution was not normal or the variance not homogeneous. Results: Enalapril and olmesartan increased serum potassium levels similarly (0.3 mmol/L and 0.24 mmol/L respectively). The percentage of patients presenting hyperkalemia higher than 5 mmol/L did not differ between treatments: 37% for olmesartan and 40% for enalapril. The mean e-GFR ranged 46.3 to 48.59 ml/mint/1.73 m2 in those treated with olmesartan and 46.8 to 48.3 ml/mint/1.73 m2 in those with enalapril and remained unchanged at the end of the study. The decreases in microalbuminuria were also similar (23% in olmesartan and 29% in enalapril patients) in the 4 weeks time point. The percentage of patients presenting hyperkalemia, even after a two month period, did not differ between treatments. There were no appreciable changes in sodium and potassium urinary excretion. Conclusions: Disturbances in potassium balance upon treatment with either olmesartan or enalapril are frequent and without differences between groups. The follow-up of these patients should include control of potassium levels, at least after the first week and the first and second month after initiating treatment
TLR2 and Nod2 Mediate Resistance or Susceptibility to Fatal Intracellular Ehrlichia Infection in Murine Models of Ehrlichiosis
Our murine models of human monocytic ehrlichiosis (HME) have shown that severe and fatal ehrlichiosis is due to generation of pathogenic T cell responses causing immunopathology and multi-organ failure. However, the early events in the liver, the main site of infection, are not well understood. In this study, we examined the liver transcriptome during the course of lethal and nonlethal infections caused by Ixodes ovatus Ehrlichia and Ehrlichia muris, respectively. On day 3 post-infection (p.i.), although most host genes were down regulated in the two groups of infected mice compared to naïve counterparts, lethal infection induced significantly higher expression of caspase 1, caspase 4, nucleotide binding oligomerization domain-containing proteins (Nod1), tumor necrosis factor-alpha, interleukin 10, and CCL7 compared to nonlethal infection. On day 7 p.i., lethal infection induced highly significant upregulation of type-1 interferon, several inflammatory cytokines and chemokines, which was associated with increased expression levels of Toll-like receptor-2 (TLR2), Nod2, MyD88, nuclear factor-kappa B (NF-kB), Caspase 4, NLRP1, NLRP12, Pycard, and IL-1β, suggesting enhanced TLR signals and inflammasomes activation. We next evaluated the participation of TLR2 and Nod2 in the host response during lethal Ehrlichia infection. Although lack of TLR2 impaired bacterial elimination and increased tissue necrosis, Nod2 deficiency attenuated pathology and enhanced bacterial clearance, which correlated with increased interferon-γ and interleukin-10 levels and a decreased frequency of pathogenic CD8+ T cells in response to lethal infection. Thus, these data indicate that Nod2, but not TLR2, contributes to susceptibility to severe Ehrlichia-induced shock. Together, our studies provide, for the first time, insight into the diversity of host factors and novel molecular pathogenic mechanisms that may contribute to severe HME. © 2013 Chattoraj et al
Friends with Benefits: Social Coupons as a Strategy to Enhance Customers’ Social Empowerment
Businesses often seek to leverage customers’ social networks to acquire new customers and stimulate word-of-mouth recommendations. While customers make brand recommendations for various reasons (e.g., incentives, reputation enhancement), they are also motivated by a desire for social empowerment—to feel an impact on others. In several multi-method studies, we show that facilitating sharing of social coupons (i.e., coupon sets that include one for self-use and one to be shared) is a unique marketing strategy that facilitates social empowerment. Firms benefit from social coupons because customers who share spend more and report greater purchase intentions than those who do not. Furthermore, we demonstrate that social coupons are most effective when the sharer’s brand relationship is new versus established. For customers with an established relationship, sharing with a receiver who also has an established relationship maximizes potential impact. Together, these studies connect social empowerment to relationship marketing and provide guidance to managers targeting social coupons
Rate-dependent Ca2+ signalling underlying the force-frequency response in rat ventricular myocytes: A coupled electromechanical modeling study
Rate-dependent effects on the Ca2+ sub-system in a rat ventricular myocyte are investigated. Here,
we employ a deterministic mathematical model describing various Ca2+ signalling pathways under
voltage clamp (VC) conditions, to better understand the important role of calmodulin (CaM) in modulating
the key control variables Ca2+/calmodulin-dependent protein kinase-II (CaMKII), calcineurin
(CaN), and cyclic adenosine monophosphate (cAMP) as they affect various intracellular targets. In
particular, we study the frequency dependence of the peak force generated by the myofilaments, the
force-frequency response (FFR). Our cell model incorporates frequency-dependent CaM-mediated spatially heterogenous interaction
of CaMKII and CaN with their principal targets (dihydropyridine (DHPR) and ryanodine (RyR) receptors
and the SERCA pump). It also accounts for the rate-dependent effects of phospholamban
(PLB) on the SERCA pump; the rate-dependent role of cAMP in up-regulation of the L-type Ca2+
channel (ICa;L); and the enhancement in SERCA pump activity via phosphorylation of PLB.Our model reproduces positive peak FFR observed in rat ventricular myocytes during voltage-clamp
studies both in the presence/absence of cAMP mediated -adrenergic stimulation. This study provides
quantitative insight into the rate-dependence of Ca2+-induced Ca2+-release (CICR) by investigating
the frequency-dependence of the trigger current (ICa;L) and RyR-release. It also highlights the relative
role of the sodium-calcium exchanger (NCX) and the SERCA pump at higher frequencies, as well
as the rate-dependence of sarcoplasmic reticulum (SR) Ca2+ content. A rigorous Ca2+ balance
imposed on our investigation of these Ca2+ signalling pathways clarifies their individual roles. Here,
we present a coupled electromechanical study emphasizing the rate-dependence of isometric force
developed and also investigate the temperature-dependence of FFR. Our model provides mechanistic biophysically based explanations for the rate-dependence of CICR,
generating useful and testable hypotheses. Although rat ventricular myocytes exhibit a positive peak
FFR in the presence/absence of beta-adrenergic stimulation, they show a characteristic increase in the
positive slope in FFR due to the presence of Norepinephrine or Isoproterenol. Our study identifies
cAMP-mediated stimulation, and rate-dependent CaMKII-mediated up-regulation of ICa;L as the key
mechanisms underlying the aforementioned positive FFR
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