510 research outputs found

    Characterization of the ABC methionine transporter from Neisseria meningitidis reveals that MetQ is a lipoprotein

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    NmMetQ is a substrate binding protein (SBP) from Neisseria meningitidis that has been identified as a surface-exposed candidate antigen for meningococcal vaccines. However, this location for NmMetQ challenges the prevailing view that SBPs in Gram-negative bacteria are localized to the periplasmic space to promote interaction with their cognate ABC transporter embedded in the bacterial inner membrane. To address the roles of NmMetQ, we characterized NmMetQ with and without its cognate ABC transporter (NmMetNI). Here, we show that NmMetQ is a lipoprotein (lipo-NmMetQ) that binds multiple methionine analogs and stimulates the ATPase activity of NmMetNI. Using single-particle electron cryo-microscopy, we determined the structures of NmMetNI in the absence and presence of lipo-NmMetQ. Based on our data, we propose that NmMetQ tethers to membranes via a lipid anchor and has dual function/topology, playing a role in NmMetNI-mediated transport at the inner-membrane in addition to moonlighting functions on the bacterial surface

    Haren: A Framework for Ad-Hoc Thread Scheduling Policies for Data Streaming Applications

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    In modern Stream Processing Engines (SPEs), numerous diverse applications, which can differ in aspects such as cost, criticality or latency sensitivity, can co-exist in the same computing node. When these differences need to be considered to control the performance of each application, custom scheduling of operators to threads is of key importance (e.g., when a smart vehicle needs to ensure that safety-critical applications always have access to computational power, while other applications are given lower, variable priorities).Many solutions have been proposed regarding schedulers that allocate threads to operators to optimize specific metrics (e.g., latency) but there is still lack of a tool that allows arbitrarily complex scheduling strategies to be seamlessly plugged on top of an SPE. We propose Haren to fill this gap. More specifically, we (1) formalize the thread scheduling problem in stream processing in a general way, allowing to define ad-hoc scheduling policies, (2) identify the bottlenecks and the opportunities of scheduling in stream processing, (3) distill a compact interface to connect Haren with SPEs, enabling rapid testing of various scheduling policies, (4) illustrate the usability of the framework by integrating it into an actual SPE and (5) provide a thorough evaluation. As we show, Haren makes it is possible to adapt the use of computational resources over time to meet the goals of a variety of scheduling policies

    Arsenic Induced Toxicity in Broiler Chicks and Its Amelioration with Ascorbic Acid: Clinical, Hematological and Pathological Study

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    This study was conducted to observe the arsenic (As) toxicity lesions in birds and to know either Vit C ameliorates these toxic effects or not. One-day-old broilers chicks (n=72) procured from a local hatchery were randomly divided into four equal groups. First group was kept as control and second group was given As (50 mg/kg BW) via crop tubing. Third group received in addition to As, Vit C (250 mg/kg BW) whereas fourth group received only Vit C. Killing by neck dislocation of randomly selected six birds from each group was carried out on experimental days 0, 16 and 32 for collection of blood and tissues specimens. Arsenic treated birds showed clinical signs of toxicity throughout the experiment than all other groups. These clinical signs included decreased body weight and feed intake, dullness, open mouth breathing, increased thirst, ruffled feathers, pale comb, skin irritation and watery diarrhea which were not significant in any other group. As treated group showed a significant (P<0.05) decrease in hematological parameters. Severe gross and histopathological changes were observed in intestines, spleen and lungs of birds fed with As than all other groups. Decreased height of villi of middle portion of small intestines was also observed in As treated birds. Villi height in Vit C treated group increased as compared to control group. It was concluded that As induces severe toxic effects in broiler birds; however, these toxic effects can be partially ameliorated by Vit C

    Adaptive Coordination Offsets for Signalized Arterial Intersections using Deep Reinforcement Learning

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    One of the most critical components of an urban transportation system is the coordination of intersections in arterial networks. With the advent of data-driven approaches for traffic control systems, deep reinforcement learning (RL) has gained significant traction in traffic control research. Proposed deep RL solutions to traffic control are designed to directly modify either phase order or timings; such approaches can lead to unfair situations -- bypassing low volume links for several cycles -- in the name of optimizing traffic flow. To address the issues and feasibility of the present approach, we propose a deep RL framework that dynamically adjusts the offsets based on traffic states and preserves the planned phase timings and order derived from model-based methods. This framework allows us to improve arterial coordination while preserving the notion of fairness for competing streams of traffic in an intersection. Using a validated and calibrated traffic model, we trained the policy of a deep RL agent that aims to reduce travel delays in the network. We evaluated the resulting policy by comparing its performance against the phase offsets obtained by a state-of-the-practice baseline, SYNCHRO. The resulting policy dynamically readjusts phase offsets in response to changes in traffic demand. Simulation results show that the proposed deep RL agent outperformed SYNCHRO on average, effectively reducing delay time by 13.21% in the AM Scenario, 2.42% in the noon scenario, and 6.2% in the PM scenario. Finally, we also show the robustness of our agent to extreme traffic conditions, such as demand surges and localized traffic incidents

    GRADE equity guidelines 3: considering health equity in GRADE guideline development: rating the certainty of synthesized evidence

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    Objectives: The aim of this paper is to describe a conceptual framework for how to consider health equity in the Grading Recommendations Assessment and Development Evidence (GRADE) guideline development process. Study Design and Setting: Consensus-based guidance developed by the GRADE working group members and other methodologists. Results: We developed consensus-based guidance to help address health equity when rating the certainty of synthesized evidence (i.e., quality of evidence). When health inequity is determined to be a concern by stakeholders, we propose five methods for explicitly assessing health equity: (1) include health equity as an outcome; (2) consider patient-important outcomes relevant to health equity; (3) assess differences in the relative effect size of the treatment; (4) assess differences in baseline risk and the differing impacts on absolute effects; and (5) assess indirectness of evidence to disadvantaged populations and/or settings. Conclusion: The most important priority for research on health inequity and guidelines is to identify and document examples where health equity has been considered explicitly in guidelines. Although there is a weak scientific evidence base for assessing health equity, this should not discourage the explicit consideration of how guidelines and recommendations affect the most vulnerable members of society

    Development model for supply chain network design by demand uncertainty and mode selection

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    It is necessary to consider the impact of demand uncertainty to model the comprehensive approach for supply chain network design. This paper presents four echelons, multiple commodity, and strategic–tactical model for designing supply chain network. Uncertain demand, transportation mode selection with lead time configuration has been considered. A numerical example has been implemented to verify the applicability of model. Finally, the simulation results and sensitivity analysis confirm that the proposed developed model is a suitable decision framework for designing the supply chain network

    A new set of integrals of motion to propagate the perturbed two-body problem

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    A formulation of the perturbed two-body problem that relies on a new set of orbital elements is presented. The proposed method represents a generalization of the special perturbation method published by Peláez et al. (Celest Mech Dyn Astron 97(2):131?150,2007) for the case of a perturbing force that is partially or totally derivable from a potential. We accomplish this result by employing a generalized Sundman time transformation in the framework of the projective decomposition, which is a known approach for transforming the two-body problem into a set of linear and regular differential equations of motion. Numerical tests, carried out with examples extensively used in the literature, show the remarkable improvement of the performance of the new method for different kinds of perturbations and eccentricities. In particular, one notable result is that the quadratic dependence of the position error on the time-like argument exhibited by Peláez?s method for near-circular motion under the J2 perturbation is transformed into linear.Moreover, themethod reveals to be competitive with two very popular elementmethods derived from theKustaanheimo-Stiefel and Sperling-Burdet regularizations

    Data mining in HIV-AIDS surveillance system: application to portuguese data

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    The Human Immunodeficiency Virus (HIV) is an infectious agent that attacks the immune system cells. Without a strong immune system, the body becomes very susceptible to serious life threatening opportunistic diseases. In spite of the great progresses on medication and prevention over the last years, HIV infection continues to be a major global public health issue, having claimed more than 36 million lives over the last 35 years since the recognition of the disease. Monitoring, through registries, of HIV-AIDS cases is vital to assess general health care needs and to support long-term health-policy control planning. Surveillance systems are therefore established in almost all developed countries. Typically, this is a complex system depending on several stakeholders, such as health care providers, the general population and laboratories, which challenges an efficient and effective reporting of diagnosed cases. One issue that often arises is the administrative delay in reports of diagnosed cases. This paper aims to identify the main factors influencing reporting delays of HIV-AIDS cases within the portuguese surveillance system. The used methodologies included multilayer artificial neural networks (MLP), naive bayesian classifiers (NB), support vector machines (SVM) and the k-nearest neighbor algorithm (KNN). The highest classification accuracy, precision and recall were obtained for MLP and the results suggested homogeneous administrative and clinical practices within the reporting process. Guidelines for reductions of the delays should therefore be developed nationwise and transversally to all stakeholders.- A. Rita Gaio was partially supported by CMUP (UID/MAT/00144/2013), which is funded by FCT (Portugal) with national (MEC) and European structural funds (FEDER), under the partnership agreement PT2020. Luis Paulo Reis was partially by the European Regional Development Fund through the programme COMPETE by FCT (Portugal) in the scope of the project PEst - UID/ CEC/00027/2015 Luis Paulo Reis and Brigida Monica Faria were partially funded by QVida+: Estimacao Continua de Qualidade de Vida para Auxilio Eficaz a Decisao Clinica, NORTE-01-0247-FEDER-003446, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement

    Realising the health and wellbeing of adolescents

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    Adolescence is a critical stage of life characterised by rapid biological, emotional, and social development. It is during this time that every person develops the capabilities required for a productive, healthy, and satisfying life. In order to make a healthy transition into adulthood, adolescents need to have access to health education, including education on sexuality1; quality health services, including sexual and reproductive; and a supportive environment both at home and in communities and countries.The global community increasingly recognises these vital needs of adolescents, and there is an emerging consensus that investing intensively in adolescents’ health and development is not only key to improving their survival and wellbeing but critical for the success of the post-2015 development agenda.2 The suggested inclusion of adolescent health in the United Nations secretary general’s Global Strategy for Women’s and Children’s Health is an expression of this growing awareness and represents an unprecedented opportunity to place adolescents on the political map beyond 2015. Ensuring that every adolescent has the knowledge, skills, and opportunities for a healthy, productive life and enjoyment of all human rights3 is essential for achieving improved health, social justice, gender equality, and other development goals.We argue that the priority in the revised Every Women Every Child Global Strategy needs to be giving adolescents a voice, expanding their choices and control over their bodies, and enabling them to develop the capabilities required for a productive, healthy, and satisfying life. We call for a global, participatory movement to improve the health of the world’s adolescents as part of a broader agenda to improve their wellbeing and uphold their rights
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