120 research outputs found

    A branch and price algorithm for the minimum power multicasting problem in wireless sensor networks

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    The Minimum Power Multicast Problem arises in wireless sensor networks and consists in assigning a transmission power to each node of a network in such a way that the total power consumption over the network is minimized, while a source node is connected to a set of destination nodes, toward which a message has to be sent periodically. A new mixed integer programming model for the problem, based on paths, is presented. A practical exact algorithm based on column generation and branch and price is derived from this model. A comparison with state-of-the-art exact methods is presented, and it is shown that the new approach compares favorably to other algorithms when the number of destination nodes is moderate. Under this condition, the proposed method is able to solve previously unmanageable instance

    Ankk1 Loss of Function Disrupts Dopaminergic Pathways in Zebrafish.

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    Ankyrin repeat and kinase domain containing 1 (ANKK1) is a member of the receptor-interacting protein serine/threonine kinase family, known to be involved in cell proliferation, differentiation and activation of transcription factors. Genetic variation within the ANKK1 locus is suggested to play a role in vulnerability to addictions. However, ANKK1 mechanism of action is still poorly understood. It has been suggested that ANKK1 may affect the development and/or functioning of dopaminergic pathways. To test this hypothesis, we generated a CRISPR-Cas9 loss of function ankk1 zebrafish line causing a 27 bp insertion that disrupts the ankk1 sequence introducing an early stop codon. We found that ankk1 transcript levels were significantly lower in ankk1 mutant (ankk127ins ) fish compared to their wild type (ankk1 +/+) siblings. In ankk1 +/+ adult zebrafish brain, ankk1 protein was detected in isocortex, hippocampus, basolateral amygdala, mesencephalon, and cerebellum, resembling the mammalian distribution pattern. In contrast, ankk1 protein was reduced in the brain of ankk127ins/27ins fish. Quantitative polymerase chain reaction analysis revealed an increase in expression of drd2b mRNA in ankk127ins at both larval and adult stages. In ankk1 +/+ adult zebrafish brain, drd2 protein was detected in cerebral cortex, cerebellum, hippocampus, and caudate homolog regions, resembling the pattern in humans. In contrast, drd2 expression was reduced in cortical regions of ankk127ins/27ins being predominantly found in the hindbrain. No differences in the number of cell bodies or axonal projections detected by anti-tyrosine hydroxylase immunostaining on 3 days post fertilization (dpf) larvae were found. Behavioral analysis revealed altered sensitivity to effects of both amisulpride and apomorphine on locomotion and startle habituation, consistent with a broad loss of both pre and post synaptic receptors. Ankk127ins mutants showed reduced sensitivity to the effect of the selective dopamine receptor antagonist amisulpride on locomotor responses to acoustic startle and were differentially sensitive to the effects of the non-selective dopamine agonist apomorphine on both locomotion and habituation. Taken together, our findings strengthen the hypothesis of a functional relationship between ANKK1 and DRD2, supporting a role for ANKK1 in the maintenance and/or functioning of dopaminergic pathways. Further work is needed to disentangle ANKK1's role at different developmental stages

    The ECRH-Power Upgrade at the Wendelstein 7-X Stellarator

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    The existing ECRH system at W7-X consists of 10 gyrotrons, with output power levels ranging from 0.6 MW up to 1.0 MW each at a frequency of 140 GHz, quasi-optical transmission lines and microwave launchers at the plasma vessel. Compared to other large fusion experiments, W7-X has a relatively low power-to-volume ratio. However high heating power is particularly necessary for achieving high plasma beta values, where the improved confinement of fast ions, one of the optimization criteria of W7-X, can be examined. It is therefore necessary to expand the ECRH systems in several consecutive steps. It is planned to increase the number of gyrotron positions from 10 to 12 and at the same time to evolve the gyrotron output power in several development steps from 1 MW to nominal 1.5 MW and, finally, up to 2 MW. At the same time, the transmission lines will also be upgraded for 2 MW operation. A special effort is also made to improve the reliability of the system by the fast control system

    Continuous vs Intermittent Meropenem Administration in Critically Ill Patients With Sepsis

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    Importance: Meropenem is a widely prescribed β-lactam antibiotic. Meropenem exhibits maximum pharmacodynamic efficacy when given by continuous infusion to deliver constant drug levels above the minimal inhibitory concentration. Compared with intermittent administration, continuous administration of meropenem may improve clinical outcomes. Objective: To determine whether continuous administration of meropenem reduces a composite of mortality and emergence of pandrug-resistant or extensively drug-resistant bacteria compared with intermittent administration in critically ill patients with sepsis. Design, setting, and participants: A double-blind, randomized clinical trial enrolling critically ill patients with sepsis or septic shock who had been prescribed meropenem by their treating clinicians at 31 intensive care units of 26 hospitals in 4 countries (Croatia, Italy, Kazakhstan, and Russia). Patients were enrolled between June 5, 2018, and August 9, 2022, and the final 90-day follow-up was completed in November 2022. Interventions: Patients were randomized to receive an equal dose of the antibiotic meropenem by either continuous administration (n = 303) or intermittent administration (n = 304). Main outcomes and measures: The primary outcome was a composite of all-cause mortality and emergence of pandrug-resistant or extensively drug-resistant bacteria at day 28. There were 4 secondary outcomes, including days alive and free from antibiotics at day 28, days alive and free from the intensive care unit at day 28, and all-cause mortality at day 90. Seizures, allergic reactions, and mortality were recorded as adverse events. Results: All 607 patients (mean age, 64 [SD, 15] years; 203 were women [33%]) were included in the measurement of the 28-day primary outcome and completed the 90-day mortality follow-up. The majority (369 patients, 61%) had septic shock. The median time from hospital admission to randomization was 9 days (IQR, 3-17 days) and the median duration of meropenem therapy was 11 days (IQR, 6-17 days). Only 1 crossover event was recorded. The primary outcome occurred in 142 patients (47%) in the continuous administration group and in 149 patients (49%) in the intermittent administration group (relative risk, 0.96 [95% CI, 0.81-1.13], P = .60). Of the 4 secondary outcomes, none was statistically significant. No adverse events of seizures or allergic reactions related to the study drug were reported. At 90 days, mortality was 42% both in the continuous administration group (127 of 303 patients) and in the intermittent administration group (127 of 304 patients). Conclusions and relevance: In critically ill patients with sepsis, compared with intermittent administration, the continuous administration of meropenem did not improve the composite outcome of mortality and emergence of pandrug-resistant or extensively drug-resistant bacteria at day 28. Trial registration: ClinicalTrials.gov Identifier: NCT03452839

    Association of kidney disease measures with risk of renal function worsening in patients with type 1 diabetes

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    Background: Albuminuria has been classically considered a marker of kidney damage progression in diabetic patients and it is routinely assessed to monitor kidney function. However, the role of a mild GFR reduction on the development of stage 653 CKD has been less explored in type 1 diabetes mellitus (T1DM) patients. Aim of the present study was to evaluate the prognostic role of kidney disease measures, namely albuminuria and reduced GFR, on the development of stage 653 CKD in a large cohort of patients affected by T1DM. Methods: A total of 4284 patients affected by T1DM followed-up at 76 diabetes centers participating to the Italian Association of Clinical Diabetologists (Associazione Medici Diabetologi, AMD) initiative constitutes the study population. Urinary albumin excretion (ACR) and estimated GFR (eGFR) were retrieved and analyzed. The incidence of stage 653 CKD (eGFR < 60 mL/min/1.73 m2) or eGFR reduction > 30% from baseline was evaluated. Results: The mean estimated GFR was 98 \ub1 17 mL/min/1.73m2 and the proportion of patients with albuminuria was 15.3% (n = 654) at baseline. About 8% (n = 337) of patients developed one of the two renal endpoints during the 4-year follow-up period. Age, albuminuria (micro or macro) and baseline eGFR < 90 ml/min/m2 were independent risk factors for stage 653 CKD and renal function worsening. When compared to patients with eGFR > 90 ml/min/1.73m2 and normoalbuminuria, those with albuminuria at baseline had a 1.69 greater risk of reaching stage 3 CKD, while patients with mild eGFR reduction (i.e. eGFR between 90 and 60 mL/min/1.73 m2) show a 3.81 greater risk that rose to 8.24 for those patients with albuminuria and mild eGFR reduction at baseline. Conclusions: Albuminuria and eGFR reduction represent independent risk factors for incident stage 653 CKD in T1DM patients. The simultaneous occurrence of reduced eGFR and albuminuria have a synergistic effect on renal function worsening

    Multicast problems in telecommunication networks

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    A matheuristic for the asymmetric capacitated vehicle routing problem

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    In this paper, we propose a novel matheuristic for the Asymmetric Capacitated Vehicle Routing Problem (ACVRP). This optimization-based approach combines some heuristic concepts with compact mixed-integer linear programming (MILP) formulations. Basically, the proposed matheuristic includes three sequential stages. First, the problem size is heuristically reduced by discarding unpromising arcs. Second, a starting feasible solution is derived. Finally, an optimization-based improvement procedure is invoked to iteratively generate near-optimal solutions. This latter procedure requires solving a sequence of two- or three-vehicle ACVRP reduced instances. A peculiar feature of the solution strategy is that all the three stages are solely based on solving compact MILP formulations using a commercial solver and it does not resort to any constructive heuristic nor metaheuristic. We describe the results of extensive computational experiments, that were carried out on a large set of benchmark instances with up to 200 nodes, and we provide empirical evidence that the proposed matheuristic often delivers high-quality solutions. 2016Scopu

    An Exact Algorithm for the Steiner Tree Problem with Delays

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    The Steiner Tree Problem with Delays (STPD) is a variant of the well-known Steiner Tree Problem in which the delay on each path between a source node and a terminal node is limited by a given maximum value. We propose a Branch-and-Cut algorithm for solving this problem using a formulation based on lifted Miller-Tucker-Zemlin subtour elimination constraints. The effectiveness of the proposed algorithm is assessed through computational experiments carried out on dense benchmark instances

    Integrated assessment of energy performance and seismic vulnerability of existing building stock at urban scale through BIM: an application to "Fiera del Levante"

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    The paper presents a research work concerned with the integrate assessment of seismic vulnerability and energy performance of existing buildings at urban scale through BIM (Building Information Modelling). At the urban scale, it is often required to manage large set of buildings, for which it is not possible to perform detailed investigation, modeling and analysis.At this scale of analysis, an additional issue is the coexistence of different building components and performance requirements (structural safety, functional and aesthetic efficiency, energy efficiency, and so on), which often have a dynamic interaction.For this reason, the modeling approach should be able to encounter this complexity and provide the interaction of multiple expertise, in order to provide optimal solutions of the critical issues and vulnerability of buildings.Within this context, the research has proposed and tested a framework structured through a suitable BIM model finalized to implementation of integrated simplified evaluation procedure of seismic vulnerability and energy performance at urban scale.The objective is to provide an innovative tool for the performance-based assessment in a context of uncertainty and incomplete information typical of the urban scale analysis.The proposed approach allows to manage information from different source and quick investigations concerns structural safety and energy efficiency, and it has been focused on the case study of "Fiera del Levante", a trade fair district extending over 280.000 m(2), composed by several buildings aged from 1929 to 2012, that host about thirty events (including international fair shows) throughout the year as well as conferences and/or exhibitions

    Multi-scale integrated assessment of existing building assets through BIM

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    The paper presents a research work concerned with the assessment of existing building assets at multiple scale of analysis, considering the complex interaction of many different components and performance requirements. Within this context, a multi-criteria approach would be required in order to define the intervention strategies: in the environmental sustainability assessment such method is already well developed and widely applied. The rehabilitation and reuse of buildings encompasses many different performance requirements, among which seismic safety and energy efficiency issues represent a particularly critical aspect, especially considering the significant evolution of the technical standards recently occurred in these fields. At the urban scale, moreover, it is often required to manage large set of buildings, for which it is not rationale – or even possible – to perform at once detailed investigation, modeling and analysis. Within this context, the research has proposed and tested the use of BIM for the definition of the knowledge framework and implementation of assessment procedures at different scale of analysis. The objective is to provide an innovative tool for the performance based assessment in a context of uncertainty and incomplete information. The approach allows to manage different “levels”, starting from poor data and information (for the first screening and analysis), and progressively more refined models with regard to object, associated data, assessment algorithms and procedures. The proposed approach has been focused on the case study of “Fiera del Levante”, a trade fair district extending over 280.000 m2, composed by several buildings aged from 1929 to 2012, that host about thirty events (including international fair shows) throughout the year as well as conferences and/or exhibition
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