16,529 research outputs found

    Are Magnetic Wind-Driving Disks Inherently Unstable?

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    There have been claims in the literature that accretion disks in which a centrifugally driven wind is the dominant mode of angular momentum transport are inherently unstable. This issue is considered here by applying an equilibrium-curve analysis to the wind-driving, ambipolar diffusion-dominated, magnetic disk model of Wardle & Konigl (1993). The equilibrium solution curves for this class of models typically exhibit two distinct branches. It is argued that only one of these branches represents unstable equilibria and that a real disk/wind system likely corresponds to a stable solution.Comment: 5 pages, 2 figures, to be published in ApJ, vol. 617 (2004 Dec 20). Uses emulateapj.cl

    The impact of human resources practices on consumers’ investment intentions

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    Purpose: Research has shown that corporate policies affect customers’ decisions. The purpose of this paper is to focus on the influence of human resources (HR) practices on investment intentions in the financial sector. Design/methodology/approach: Data were obtained from 548 managers and management students. Participants were presented real news regarding two banks with contrasting HR practices. Subsequently, they had to choose – from a given virtual amount – their investment allocations. Findings: Results primarily showed that participants decided to invest more money in the bank which was more profitable to them, regardless of that bank’s HR practice. But, most importantly, when the news was specifically addressed to the in-group (managers), participants decided to invest more money in the bank with the HR practice by which they identified more, although being less profitable to them. Originality/value: The findings demonstrate the urgency for organizations to manage effectively their HR practices, as they serve as a vehicle to corporate reputation, thus affecting the relationship with the stakeholders and investors’ decisions.info:eu-repo/semantics/acceptedVersio

    Classifying residential real estate based on their exposure to crime: a research agenda

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    Criminality and sense of security in residential areas are always present in the mind of citizens, and directly affect the work of police authorities, real estate agents and society at large. This study proposes the development of a multiple criteria model for the classification of residential areas based on their exposure to crime. By combining cognitive mapping with the Measuring Attractiveness by a Categorical Based Evaluation Technique (MACBETH), we also aim to increase transparency in the classification process of residential real estate, allowing improvement initiatives to be applied and crime rates to be reduced. The major difference between our proposal and the extant literature is the fact that the information collected from criminal, urbanism and real estate experts, who deal with crime adversities on a daily basis, will be analyzed and discussed during presential group meetings, allowing realism to be incorporated into the evaluation mechanism. The current proposal is a research agenda, and results will not yet be presented

    Antimicrobial potential of Eucalyptus globulus against biofilms of Staphylococcus aureus isolated from bovine mastitis

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    Staphylococcus aureus are among the most common species isolated from bovine mastitis. The pathogenesis of this bacterium is facilitated by a number of virulence factors, including the ability to adhere to abiotic surfaces and/or host tissues often leading to biofilms formation. From the clinical perspective, the most important feature of Staphylococcus species biofilms is their high tolerance to the conventional antimicrobial therapy. So, the increasing number of bovine mastitis and the higher levels of Staphylococcus species resistance to traditional antimicrobial agents are considered an important alert for the necessity to focus the future research on identification and development of new strategies to combat S. aureus mastitis. Recently, the interest in natural alternatives based on plant extracts has been rising. In addition to their health benefits, their antimicrobial potential has been increasingly reported. Taking this into consideration, the evaluation of hydromethanolic extracts of E. globulus against S. aureus biofilms was tested and compared with penicillin, one of the antibiotics most often used in the treatment of cattle infections. All mastitis isolates tested were good-biofilm producers. As expected penicillin has demonstrated poor activity against S. aureus biofilms (<1 log reduction). However, E. globulus Labill was bactericidal, promoting a biofilm cell reduction of 2-3 log. Therefore, the present work showed the potential antimicrobial activity of E. globulus against S. aureus from bovine mastitis, namely in biofilm mode of growth and drew attention to its promising use as an alternative to penicillin

    Extracting clinical knowledge from electronic medical records

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    As the adoption of Electronic Medical Records (EMRs) rises in the healthcare institutions, these resources' importance increases because of the clinical information they contain about patients. However, the unstructured information in the form of clinical narratives present in those records, makes it hard to extract and structure useful clinical knowledge. This unstructured information limits the potential of the EMRs, because the clinical information these records contain can be used to perform important tasks inside healthcare institutions such as searching, summarization, decision support and statistical analysis, as well as be used to support management decisions or serve for research. These tasks can only be done if the unstructured clinical information from the narratives is properly extracted, structured and transformed in clinical knowledge. Usually, this extraction is made manually by healthcare practitioners, which is not efficient and is error-prone. This research uses Natural Language Processing (NLP) and Information Extraction (IE) techniques, in order to develop a pipeline system that can extract clinical knowledge from unstructured clinical information present in Portuguese EMRs, in an automated way, in order to help EMRs to fulfil their potential.info:eu-repo/semantics/publishedVersio

    Mitochondrial- and Endoplasmic Reticulum-Associated Oxidative Stress in Alzheimer's Disease: From Pathogenesis to Biomarkers

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    Alzheimer's disease (AD) is the most common cause of dementia in the elderly, affecting several million of people worldwide. Pathological changes in the AD brain include the presence of amyloid plaques, neurofibrillary tangles, loss of neurons and synapses, and oxidative damage. These changes strongly associate with mitochondrial dysfunction and stress of the endoplasmic reticulum (ER). Mitochondrial dysfunction is intimately linked to the production of reactive oxygen species (ROS) and mitochondrial-driven apoptosis, which appear to be aggravated in the brain of AD patients. Concomitantly, mitochondria are closely associated with ER, and the deleterious crosstalk between both organelles has been shown to be involved in neuronal degeneration in AD. Stimuli that enhance expression of normal and/or folding-defective proteins activate an adaptive unfolded protein response (UPR) that, if unresolved, can cause apoptotic cell death. ER stress also induces the generation of ROS that, together with mitochondrial ROS and decreased activity of several antioxidant defenses, promotes chronic oxidative stress. In this paper we discuss the critical role of mitochondrial and ER dysfunction in oxidative injury in AD cellular and animal models, as well as in biological fluids from AD patients. Progress in developing peripheral and cerebrospinal fluid biomarkers related to oxidative stress will also be summarized

    Realization of Rectangular Artificial Spin Ice and Direct Observation of High Energy Topology

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    In this letter, we have constructed and experimentally investigated frustrated arrays of dipoles forming two-dimensional artificial spin ices with different lattice parameters (rectangular arrays with horizontal and vertical lattice spacings denoted by aa and bb respectively). Arrays with three different ratios γ=a/b=2\gamma =a/b = \sqrt{2}, 3\sqrt{3} and 4\sqrt{4} are studied. Theoretical calculations of low-energy demagnetized configurations for these same parameters are also presented. Experimental data for demagnetized samples confirm most of the theoretical results. However, the highest energy topology (doubly-charged monopoles) does not emerge in our theoretical model, while they are seen in experiments for large enough γ\gamma. Our results also insinuate that magnetic monopoles may be almost free in rectangular lattices with a critical ratio γ=γc=3\gamma = \gamma_{c} = \sqrt{3}, supporting previous theoretical predictions

    Enhanced Safety Surveillance of Influenza Vaccines in General Practice, Winter 2015-16: Feasibility Study

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    BACKGROUND: The European Medicines Agency (EMA) requires vaccine manufacturers to conduct enhanced real-time surveillance of seasonal influenza vaccination. The EMA has specified a list of adverse events of interest to be monitored. The EMA sets out 3 different ways to conduct such surveillance: (1) active surveillance, (2) enhanced passive surveillance, or (3) electronic health record data mining (EHR-DM). English general practice (GP) is a suitable setting to implement enhanced passive surveillance and EHR-DM. OBJECTIVE: This study aimed to test the feasibility of conducting enhanced passive surveillance in GP using the yellow card scheme (adverse events of interest reporting cards) to determine if it has any advantages over EHR-DM alone. METHODS: A total of 9 GPs in England participated, of which 3 tested the feasibility of enhanced passive surveillance and the other 6 EHR-DM alone. The 3 that tested EPS provided patients with yellow (adverse events) cards for patients to report any adverse events. Data were extracted from all 9 GPs' EHRs between weeks 35 and 49 (08/24/2015 to 12/06/2015), the main period of influenza vaccination. We conducted weekly analysis and end-of-study analyses. RESULTS: Our GPs were largely distributed across England with a registered population of 81,040. In the week 49 report, 15,863/81,040 people (19.57% of the registered practice population) were vaccinated. In the EPS practices, staff managed to hand out the cards to 61.25% (4150/6776) of the vaccinees, and of these cards, 1.98% (82/4150) were returned to the GP offices. Adverse events of interests were reported by 113 /7223 people (1.56%) in the enhanced passive surveillance practices, compared with 322/8640 people (3.73%) in the EHR-DM practices. CONCLUSIONS: Overall, we demonstrated that GPs EHR-DM was an appropriate method of enhanced surveillance. However, the use of yellow cards, in enhanced passive surveillance practices, did not enhance the collection of adverse events of interests as demonstrated in this study. Their return rate was poor, data entry from them was not straightforward, and there were issues with data reconciliation. We concluded that customized cards prespecifying the EMA's adverse events of interests, combined with EHR-DM, were needed to maximize data collection. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1136/bmjopen-2016-015469

    Random Costs in Combinatorial Optimization

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    The random cost problem is the problem of finding the minimum in an exponentially long list of random numbers. By definition, this problem cannot be solved faster than by exhaustive search. It is shown that a classical NP-hard optimization problem, number partitioning, is essentially equivalent to the random cost problem. This explains the bad performance of heuristic approaches to the number partitioning problem and allows us to calculate the probability distributions of the optimum and sub-optimum costs.Comment: 4 pages, Revtex, 2 figures (eps), submitted to PR
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