Yahoo!

About: Yahoo! is a company organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Web search query. The organization has 26749 authors who have published 29915 publications receiving 732583 citations. The organization is also known as: Yahoo! Inc. & Maudwen-Yahoo! Inc.

Mechanistic Insights into the Antimicrobial Actions of Metallic Nanoparticles and Their Implications for Multidrug Resistance

Abstract: Multiple drug-resistant bacteria are a severe and growing public health concern. Because relatively few antibiotics have been approved over recent years and because of the inability of existing antibiotics to combat bacterial infections fully, demand for unconventional biocides is intense. Metallic nanoparticles (NPs) offer a novel potential means of fighting bacteria. Although metallic NPs exert their effects through membrane protein damage, superoxide radicals and the generation of ions that interfere with the cell granules leading to the formation of condensed particles, their antimicrobial potential, and mechanisms of action are still debated. This article discusses the action of metallic NPs as antibacterial agents, their mechanism of action, and their effect on bacterial drug resistance. Based on encouraging data about the antibacterial effects of NP/antibiotic combinations, we propose that this concept be thoroughly researched to identify means of combating drug-resistant bacteria.

Left atrial anatomy revisited.

Abstract: Recent decades have seen rapid developments in arrhythmia treatment, especially the use of catheter ablation. Although the substrates of atrial fibrillation, its initiation and maintenance, remain to be fully elucidated, catheter ablation in the left atrium has become a therapeutic option for patients with this arrhythmia. With ablation techniques, various isolation lines and focal targets are deployed; the majority of these are anatomic approaches. It has been over a decade since we published our first article on the anatomy of the left atrium relevant to interventional electrophysiologists.1 Our aim then, as now, was to increase awareness of anatomic structures inside the left atrium. In this review of anatomy, we revisit the left atrium, inside as well as outside, for a better understanding of the atrial component parts and the spatial relationships of specific structures. ### Location and Atrial Walls Viewed from the frontal aspect of the chest, the left atrium is the most posteriorly situated of the cardiac chambers. Owing to the obliquity of the plane of the atrial septum and the different levels of the orifices of the mitral and tricuspid valves, the left atrial chamber is more posteriorly and superiorly situated relative to the right atrial chamber. The pulmonary veins enter the posterior part of the left atrium with the left veins located more superior than the right veins. The transverse pericardial sinus lies anterior to the left atrium, and in front of the sinus is the root of the aorta. The tracheal bifurcation, the esophagus, and descending thoracic aorta are immediately behind the pericardium overlying the posterior wall of the left atrium. Further behind is the vertebral column. Following the direction of blood flow, the atrial chamber begins at the pulmonary veno-atrial junctions and terminates at the fibro-fatty tissue plane that marks the atrioventricular junction at the mitral orifice. The walls …

Risk Factors for Postoperative Infectious Complications in Noncolorectal Abdominal Surgery A Multivariate Analysis Based on a Prospective Multicenter Study of 4718 Patients

Abstract: Hypothesis Infectious complications are the main causes of postoperative morbidity in abdominal surgery. Identification of risk factors, which could be avoided in the perioperative period, may reduce the rate of postoperative infectious complications. Design A database was established from 3 prospective, randomized, multicenter studies. Multivariate analysis was performed using nonconditional logistic regression expressed as an odds ratio (OR). Setting Multicenter studies (ie, private medical centers, institutional hospitals, and university hospitals). Patients From June 1982 to September 1996, a database was established containing the information of 4718 patients who underwent noncolorectal abdominal surgery. Main Outcome Measures The dependent variables studied included surgical site infection (SSI) (divided into parietal and deep infectious complications with or without fistulas) and global infectious complications (SSI and extraparietal and abdominal infectious complications). Results The rate of global infectious complications was 13.3%; SSI, 4.05%; parietal infectious complications, 2.2%; deep infectious complications with fistulas, 2.18%; and deep infectious complications without fistulas, 1.38%. In multivariate analysis, the following 7 independent risk factors for global infectious complications have been identified: age (60-74 years, OR, 1.64; ≥75 years, OR, 1.45); being underweight (OR, 1.51); having cirrhosis (OR, 2.45), having a vertical abdominal incision (OR, 1.66); having a suture placed or an anastomis of the bowel (OR, 1.48) in the digestive tract; having a prolonged operative time (61-120 minutes, OR, 1.66; 121 minutes, OR, 2.72); and being categorized as having a class 4 surgical site (ie, obese patients or having a risk factor of a healing defect) (OR, 1.66). Ceftriaxone sodium therapy was identified as a protective factor (OR, 0.43). In multivariate analysis, the following 5 independent risk factors for SSI have been identified: the existence of a preoperative cutaneous abscess or cutaneous necrosis (OR, 4.75), having a suture placed or an anastomosis of the bowel (OR, 1.82) in the digestive tract, having postoperative abdominal drainage (OR, 2.15), undergoing a surgicial procedure for the treatment of cancer (OR, 1.74), and receiving curative anticoagulant therapy (OR, 3.33) postoperatively. Conclusions Our data show that risk factors for SSI and for global infectious complications are disparate. Indeed, only the placement of a suture or having an anastomosis of the bowel in the digestive tract is a risk factor for both SSI and global infections. Some of these factors may be modifiable before or during the surgical procedure to reduce the infection rate or to prevent postoperative complications.

Partitioning default effects: Why people choose not to choose

Abstract: Default options exert an influence in areas as varied as retirement program design, organ donation policy, and consumer choice. Past research has offered potential reasons why no-action defaults matter: (a) effort, (b) implied endorsement, and (c) reference dependence. The first two of these explanations have been experimentally demonstrated, but the latter has received far less attention. In three experiments we produce default effects and demonstrate that reference dependence can play a major role in their effectiveness. We find that the queries formulated by defaults can produce differences in constructed preferences and further that manipulating queries can also mitigate default effects. The experimental context involves two environmentally consequential alternatives: cheap, inefficient incandescent light bulbs, and expensive, efficient compact fluorescent bulbs. Within this context we also measure the impact of each potential rationale for a default effect. (PsycINFO Database Record (c) 2011 APA, all rights reserved). Language: en

Monte Carlo Sampling for Regret Minimization in Extensive Games

Abstract: Sequential decision-making with multiple agents and imperfect information is commonly modeled as an extensive game. One efficient method for computing Nash equilibria in large, zero-sum, imperfect information games is counterfactual regret minimization (CFR). In the domain of poker, CFR has proven effective, particularly when using a domain-specific augmentation involving chance outcome sampling. In this paper, we describe a general family of domain-independent CFR sample-based algorithms called Monte Carlo counterfactual regret minimization (MCCFR) of which the original and poker-specific versions are special cases. We start by showing that MCCFR performs the same regret updates as CFR on expectation. Then, we introduce two sampling schemes: outcome sampling and external sampling, showing that both have bounded overall regret with high probability. Thus, they can compute an approximate equilibrium using self-play. Finally, we prove a new tighter bound on the regret for the original CFR algorithm and relate this new bound to MCCFR's bounds. We show empirically that, although the sample-based algorithms require more iterations, their lower cost per iteration can lead to dramatically faster convergence in various games.