418 research outputs found

    Throughput Maximization in the Speed-Scaling Setting

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    We are given a set of nn jobs and a single processor that can vary its speed dynamically. Each job JjJ_j is characterized by its processing requirement (work) pjp_j, its release date rjr_j and its deadline djd_j. We are also given a budget of energy EE and we study the scheduling problem of maximizing the throughput (i.e. the number of jobs which are completed on time). We propose a dynamic programming algorithm that solves the preemptive case of the problem, i.e. when the execution of the jobs may be interrupted and resumed later, in pseudo-polynomial time. Our algorithm can be adapted for solving the weighted version of the problem where every job is associated with a weight wjw_j and the objective is the maximization of the sum of the weights of the jobs that are completed on time. Moreover, we provide a strongly polynomial time algorithm to solve the non-preemptive unweighed case when the jobs have the same processing requirements. For the weighted case, our algorithm can be adapted for solving the non-preemptive version of the problem in pseudo-polynomial time.Comment: submitted to SODA 201

    TopicViz: Semantic Navigation of Document Collections

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    When people explore and manage information, they think in terms of topics and themes. However, the software that supports information exploration sees text at only the surface level. In this paper we show how topic modeling -- a technique for identifying latent themes across large collections of documents -- can support semantic exploration. We present TopicViz, an interactive environment for information exploration. TopicViz combines traditional search and citation-graph functionality with a range of novel interactive visualizations, centered around a force-directed layout that links documents to the latent themes discovered by the topic model. We describe several use scenarios in which TopicViz supports rapid sensemaking on large document collections

    Individual Privacy and Online Services

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    We explore consumer trade-offs between better performance through tailoring of online services to their individual needs and greater privacy as a result of reduced disclosure of personal information. We show that individuals have different willingness to accept loss of privacy that is a function of (1) the individual and his/her preferences, because the variation in demands for privacy is not uniform across individuals, (2) the service Domain, because individuals demand more privacy in some Domains than they do in others and (3) these differences themselves differ among consumers as well

    The adolescent girls vulnerability index: Guiding strategic investment in Uganda

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    Adolescence (from the ages of 10 to 19 years) is a critical stage of human development during which children experience rapid social, physical, psychological, and emotional changes on the path from childhood to adulthood. The decisions that are made during this period of life affect not only the individual well-being of young people, but also the well-being of the entire society. The Adolescent Girls Multilevel Vulnerability Index (AGI) was developed based on a growing recognition of the need to channel resources to vital—yet highly vulnerable and vastly underserved—populations of adolescent girls in Uganda specifically, and the East and Southern Africa region in general. AGI aims to be a summary indicator that can serve as an advocacy tool to draw attention to adolescent girls, a rigorous measure to inform decisions about policymaking and macro-level resource allocation, and an instrument for planning and monitoring progress. The report is a joint collaboration between the Government of Uganda, UNICEF, and the Population Council

    Surface Cytotoxic T Lymphocyte–associated Antigen 4 Partitions Within Lipid Rafts and Relocates to the Immunological Synapse under Conditions of Inhibition of T Cell Activation

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    T cell activation through the T cell receptor (TCR) involves partitioning of receptors into discrete membrane compartments known as lipid rafts, and the formation of an immunological synapse (IS) between the T cell and antigen-presenting cell (APC). Compartmentalization of negative regulators of T cell activation such as cytotoxic T lymphocyte–associated antigen-4 (CTLA-4) is unknown. Recent crystal structures of B7-ligated CTLA-4 suggest that it may form lattices within the IS which could explain the mechanism of action of this molecule. Here, we show that after T cell stimulation, CTLA-4 coclusters with the TCR and the lipid raft ganglioside GM1 within the IS. Using subcellular fractionation, we show that most lipid raft-associated CTLA-4 is on the T cell surface. Such compartmentalization is dependent on the cytoplasmic tail of CTLA-4 and can be forced with a glycosylphosphatidylinositol-anchor in CTLA-4. The level of CTLA-4 within lipid rafts increases under conditions of APC-dependent TCR–CTLA-4 coligation and T cell inactivation. However, raft localization, although necessary for inhibition of T cell activation, is not sufficient for CTLA-4–mediated negative signaling. These data demonstrate that CTLA-4 within lipid rafts migrates to the IS where it can potentially form lattice structures and inhibit T cell activation

    Dynamical climatic model for time to flowering in Vigna radiata

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    Background: Phenology data collected recently for about 300 accessions of Vigna radiata (mungbean) is an invaluable resource for investigation of impacts of climatic factors on plant development. Results: We developed a new mathematical model that describes the dynamic control of time to flowering by daily values of maximal and minimal temperature, precipitation, day length and solar radiation. We obtained model parameters by adaptation to the available experimental data. The models were validated by cross-validation and used to demonstrate that the phenology of adaptive traits, like flowering time, is strongly predicted not only by local environmental factors but also by plant geographic origin and genotype. Conclusions: Of local environmental factors maximal temperature appeared to be the most critical factor determining how faithfully the model describes the data. The models were applied to forecast time to flowering of accessions grown in Taiwan in future years 2020-2030

    β-Cyclodextrins grafted with chiral amino acids: A promising supramolecular stabilizer of nanoparticles for asymmetric hydrogenation?

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    International audienceWater-soluble ruthenium nanoparticles stabilized by randomly methylated β-cyclodextrins (RaMeCDs) grafted with chiral amino-acid moieties like l-alanine (Ala) and l-leucine (Leu) were prepared in aqueous solution by two approaches: (i) a one-step hydrogen reduction of ruthenium trichloride as metal source in the presence of appropriate cyclodextrins (one-pot method) or (ii) a NaBH4 reduction of the metal salts, followed by the stabilization of ruthenium hydrosol by the addition of chirally modified RaMeCDs (cascade method). The influence of the ligand's nature and the synthesis methodologies on the size, dispersion and surface properties of the obtained ruthenium colloids were studied by TEM and NMR analyses. The spherical ruthenium suspensions contain very small particles (0.82-1.00 nm) with narrow size distributions. Their catalytic properties were evaluated in biphasic hydrogenation of various prochiral compounds (olefins, ketones and disubstituted arenes) showing promising results in terms of activity and selectivity. Nevertheless, no significant enantiomeric excesses were observed

    Boundary-Layer Stability Analysis of the Mean Flows Obtained Using Unstructured Grids

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    Boundary-layer stability analyses of mean flows extracted from unstructured-grid Navier- Stokes solutions have been performed. A procedure has been developed to extract mean flow profiles from the FUN3D unstructured-grid solutions. Extensive code-to-code validations have been performed by comparing the extracted mean ows as well as the corresponding stability characteristics to the predictions based on structured-grid solutions. Comparisons are made on a range of problems from a simple at plate to a full aircraft configuration-a modified Gulfstream-III with a natural laminar flow glove. The future aim of the project is to extend the adjoint-based design capability in FUN3D to include natural laminar flow and laminar flow control by integrating it with boundary-layer stability analysis codes, such as LASTRAC

    Revisiting the Applicability of Adult Early Post-Operative Nausea and Vomiting Risk Factors for the Paediatric Patient: A Prospective Study Using Cotinine Levels in Children Undergoing Adenotonsillectomies

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    Background and Aims: Post-operative vomiting (POV) in children remains a significant clinical problem. This prospective study aims to investigate the applicability of well-established adult early post-operative nausea and vomiting (PONV) risk factors on paediatric POV after adenotonsillectomies under regulated anaesthetic conditions. Methods: After Institutional Review Board approval, 213 children aged 3–10-year-old were enrolled. The participants had pre-operative questionnaires completed, followed protocolised anaesthetic plans and had saliva analysed for cotinine. The primary outcomes were POV as correlated with age, gender, family or personal history of PONV, motion sickness history, opioid use, surgical time, anaesthetic time and environmental tobacco smoke (ETS) exposure, as assessed by cotinine levels and questionnaire reports. Data on analgesics, antiemetics and POV incidence before post-anaesthesia care unit discharge were collected. Statistical analysis was done through multiple logistic regression. Results: A total of 200 patients finalised the study. Early POV occurred in 32%. Family history of PONV (odds ratio [OR] = 5.3, P \u3c 0.01) and motion sickness history (OR = 4.4, P = 0.02) were highly significant risk factors. Age reached borderline statistical significance (OR = 1.4, P = 0.05). None of the other factors reached statistical significance. Conclusion: Early POV occurs frequently in paediatric patients undergoing adenotonsillectomies. In this paediatric-aged group, the incidence of POV was affected by the family history of PONV, and history of motion sickness. Age, female gender, opioid use, surgical and anaesthetic times did not affect the incidence of POV. ETS exposure, as assessed by cotinine levels and questionnaire reports, had no protective effect on early paediatric POV
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