83 research outputs found

    Poincar\'e and sl(2) algebras of order 3

    Full text link
    In this paper we initiate a general classification for Lie algebras of order 3 and we give all Lie algebras of order 3 based on sl(2,C)\mathfrak{sl}(2,\mathbb C) and iso(1,3)\mathfrak{iso}(1,3) the Poincar\'e algebra in four-dimensions. We then set the basis of the theory of the deformations (in the Gerstenhaber sense) and contractions for Lie algebras of order 3.Comment: Title and presentation change

    A systematic review highlights the need to improve the quality and applicability of trials of physical therapy interventions for low back pain

    Full text link
    Objectives: The objective of this study was to review and assess the methodological quality of randomized controlled trials that test physical therapy interventions for low back pain. Study Design and Setting: This is a systematic review of trials of physical therapy interventions to prevent or treat low back pain (of any duration or type) in participants of any age indexed on the Physiotherapy Evidence Database (PEDro). Existing PEDro scale ratings were used to evaluate methodological quality. Results: This review identified 2,215 trials. The majority of trials were for adults (n = 2136, 96.4%), low back pain without specific etiology (n = 1,863, 84.1%), and chronic duration (n = 947, 42.8%). The quality of trials improved over time; however, most were at risk of bias. Less than half of the trials concealed allocation to intervention (n = 813, 36.7%), used intention-to-treat principles (n = 778, 35.1%), and blinded assessors (n = 810, 36.6%), participants (n = 174, 7.9%), and therapists (n = 39, 1.8%). These findings did not vary by the type of therapy. Conclusion: Most trials that test physical therapy interventions for low back pain have methodological limitations that could bias treatment effect estimates. Greater attention to methodological features, such as allocation concealment and the reporting of intention-to-treat effects, would improve the quality of trials testing physical therapy interventions for low back pain

    The Threshold Bias Model: A Mathematical Model for the Nomothetic Approach of Suicide

    Get PDF
    Comparative and predictive analyses of suicide data from different countries are difficult to perform due to varying approaches and the lack of comparative parameters.A simple model (the Threshold Bias Model) was tested for comparative and predictive analyses of suicide rates by age. The model comprises of a six parameter distribution that was applied to the USA suicide rates by age for the years 2001 and 2002. Posteriorly, linear extrapolations are performed of the parameter values previously obtained for these years in order to estimate the values corresponding to the year 2003. The calculated distributions agreed reasonably well with the aggregate data. The model was also used to determine the age above which suicide rates become statistically observable in USA, Brazil and Sri Lanka.The Threshold Bias Model has considerable potential applications in demographic studies of suicide. Moreover, since the model can be used to predict the evolution of suicide rates based on information extracted from past data, it will be of great interest to suicidologists and other researchers in the field of mental health

    Dengue-2 Structural Proteins Associate with Human Proteins to Produce a Coagulation and Innate Immune Response Biased Interactome

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Dengue virus infection is a public health threat to hundreds of millions of individuals in the tropical regions of the globe. Although Dengue infection usually manifests itself in its mildest, though often debilitating clinical form, dengue fever, life-threatening complications commonly arise in the form of hemorrhagic shock and encephalitis. The etiological basis for the virus-induced pathology in general, and the different clinical manifestations in particular, are not well understood. We reasoned that a detailed knowledge of the global biological processes affected by virus entry into a cell might help shed new light on this long-standing problem.</p> <p>Methods</p> <p>A bacterial two-hybrid screen using DENV2 structural proteins as bait was performed, and the results were used to feed a manually curated, global dengue-human protein interaction network. Gene ontology and pathway enrichment, along with network topology and microarray meta-analysis, were used to generate hypothesis regarding dengue disease biology.</p> <p>Results</p> <p>Combining bioinformatic tools with two-hybrid technology, we screened human cDNA libraries to catalogue proteins physically interacting with the DENV2 virus structural proteins, Env, cap and PrM. We identified 31 interacting human proteins representing distinct biological processes that are closely related to the major clinical diagnostic feature of dengue infection: haemostatic imbalance. In addition, we found dengue-binding human proteins involved with additional key aspects, previously described as fundamental for virus entry into cells and the innate immune response to infection. Construction of a DENV2-human global protein interaction network revealed interesting biological properties suggested by simple network topology analysis.</p> <p>Conclusions</p> <p>Our experimental strategy revealed that dengue structural proteins interact with human protein targets involved in the maintenance of blood coagulation and innate anti-viral response processes, and predicts that the interaction of dengue proteins with a proposed human protein interaction network produces a modified biological outcome that may be behind the hallmark pathologies of dengue infection.</p

    Evaluation of the EUROSEM model using data from the Catsop watershed, The Netherlands.

    Get PDF
    The performance of the EUROSEM model is evaluated for a catchment in the Netherlands. The model is calibrated using observed hydrographs and sedigraphs by interactively changing the input parameters net capillary drive, initial soil moisture content, saturated hydraulic conductivity, cohesion, Manning's n and the detachability of soil particles. Storms with characteristics similar to the calibration storms were simulated well, whereas the model did not perform too well for storms being significantly different. Simulation of soil loss was generally too high though the poor quality of observed soil loss made it difficult to assess the true performance of the model. Through a plus and minus 10% sensitivity analysis, it was revealed that the model was most sensitive to changes in the initial volumetric moisture content of the soil and Manning's n and at the same time, the sensitivity analysis proved to be both condition- and site-specific in nature. Because of the difficulties of parameterising the model, it is recommended that in future applications of the model, minimum and maximum output values should be included as the output. Improved within storm modelling is needed, particularly to model conditions where crusting is widespread in the study area

    Provision of Additional Inertia Support for a Power System Network Using Battery Energy Storage System

    No full text
    Battery energy storage system (BESS) will play important roles in the operation of future power systems integrated with high penetration of renewable energy sources. In this work, battery energy storage system (BESS) is equipped with a frequency controller to provide additional inertia support in a power system network made of wind power renewable energy and conventional sources. Several scenarios such as magnitude of power imbalance, transmission line length, variation in wind power penetration level, battery sizing, varying grid inertia were investigated to understand their impacts on the effectiveness of BESS in providing additional inertia support during power system contingencies. Time-domain simulation results of the studied network show that when the transmission line lengths are doubled, the rate of change of frequency (RoCoF) decreased by about 76&#x0025; resulting in the minimum frequency rising from 49.39Hz to 49.85Hz during the power system disturbance. Besides, by increasing the size of BESS from 50MW to 130MW, the RoCoF was improved from &#x2212;0.43876Hz/s to &#x2212;0.30668Hz/s thereby raising the minimum frequency from 48.98Hz to 49.67Hz. Further results from the simulations show that when the magnitude of power imbalance was increased from 150 MW to 375MW, the BESS could not effectively provide additional support as the output power from the power converter remained fairly constant at about 60MW

    Turkey and the Anglo-Soviet Alliance, June 1941 to September 1943

    No full text
    • …
    corecore