5,074 research outputs found

    Distributed Optimization of Multi-Cell Uplink Co-operation with Backhaul Constraints

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    We address the problem of uplink co-operative reception with constraints on both backhaul bandwidth and the receiver aperture, or number of antenna signals that can be processed. The problem is cast as a network utility (weighted sum rate) maximization subject to computational complexity and architectural bandwidth sharing constraints. We show that a relaxed version of the problem is convex, and can be solved via a dual-decomposition. The proposed solution is distributed in that each cell broadcasts a set of {\em demand prices} based on the data sharing requests they receive. Given the demand prices, the algorithm determines an antenna/cell ordering and antenna-selection for each scheduled user in a cell. This algorithm, referred to as {\em LiquidMAAS}, iterates between the preceding two steps. Simulations of realistic network scenarios show that the algorithm exhibits fast convergence even for systems with large number of cells.Comment: IEEE ICC Conference, 201

    IMPLEMENTASI TEKNIK PEMBANGKIT KOLOM PADA METODE DEKOMPOSISI DANTZIG-WOLFE DALAM PENYELESAIAN MASALAH PEMROGRAMAN LINEAR BLOCK–ANGULER

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    Suatu masalah pemrograman linear dikatakan berbentuk Primal block-anguler jika memiliki sejumlah kendala umum, yaitu kendala yang memuat semua variabel yang muncul dalam masalah. Penelitian ini bertujuan untuk menyelesaiakan masalah pemrograman linear block-anguler dengan menerapkan metode Dekomposisi Dantzig-wolfe dan pengimplementasian teknik pembangkit kolom pada metode tersebut. Dengan demikian, optimasi masalah tersebut didapat dengan lebih mudah dan sederhana. Masalah yang kemudian muncul adalah masalah pemrograman linear yang mempunya

    Circadian rhythms in insecticide susceptibility, metabolic enzyme activity, and gene expression in Cimex lectularius (Hemiptera: Cimicidae).

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    Many insect species display daily variation of sensitivity to insecticides when they are exposed to the same concentration at different times during the day. To date, this has not been investigated in bed bugs. To address this, we explored circadian rhythms in insecticide susceptibility, xenobiotic metabolizing (XM) gene expressions, and metabolic detoxification in the common bed bug, Cimex lectularius. An insecticide susceptible Monheim strain of C. lectularius was most tolerant of deltamethrin during the late photophase at ZT9 (i.e. nine hours after light is present in the light-dark cycle (LD) cycle) and similarly repeated at CT9 (i.e. nine hours into the subjective day in constant darkness (DD)) suggesting endogenous circadian involvement in susceptibility to deltamethrin. No diel rhythm was observed against imidacloprid insecticide despite significant daily susceptibility in both LD and DD conditions. Rhythmic expressions of metabolic detoxification genes, GSTs1 and CYP397A1 displayed similar expression patterns with total GST and P450 enzyme activities in LD and DD conditions, respectively. The oscillation of mRNA levels of GSTs1 and CYP397A1 was found consistent with peak phases of deltamethrin susceptibility in C. lectularius. This study demonstrates that circadian patterns of metabolic detoxification gene expression occur within C. lectularius. As a consequence, insecticide efficacy can vary dramatically throughout a 24 hour period

    A Review of Cardiogenic Shock in Acute Myocardial Infarction

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    Cardiogenic shock continues to be the most common cause of death in patients hospitalized with acute myocardial infarction. It has also been frequently associated with ST-segment elevation myocardial infarction (STEMI) and patients with co-morbidities. Cardiogenic shock presents with low systolic blood pressure and clinical signs of hypoperfusion. Rapid diagnosis and supportive therapy in the form of medications, airway support and intra-aortic balloon counterpulsation is required. Initial stabilization can be followed by reperfusion by fibrinolytic therapy, emergent percutaneous intervention (PCI) or coronary artery bypass grafting (CABG). The latter two have been found to decrease mortality in the long term. Research is being carried out on the role of inflammatory mediators in the clinical manifestation of cardiogenic shock. Mechanical support devices also show promise in the future

    Early cryoprecipitate transfusion versus standard care in severe postpartum haemorrhage: a pilot cluster-randomised trial

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    The trial was prospectively registered on ISRCTN (12146519). The trial was approved by the NHS LondonBrighton and Sussex Research Ethics Committee and the NHS Confidentiality Advisory Group. The study was funded by Barts Charity. We would like to acknowledge the support of the Joint Research Management Office, Queen Mary University of London as sponsor for the study; the contributions of members of Katie's Team, the East London women's health research patient and public advisory group; and the clinical, laboratory and maternity research teams at Barts Health NHS Trust hospitals and Homerton University Hospital. We are also grateful for all the support and advice provided by the project steering committee chaired by an independent consultant anaesthetist (M. Wilson, University of Sheffield), with four other independent members: A. Khalil, St George's University Hospital; B. Leurent, London School of Hygiene and Tropical Medicine; N. Moss, lay representative; and S. Robinson, Guy's and St Thomas' NHS Trust. No other external funding or competing interests declared.There is a lack of evidence evaluating cryoprecipitate transfusion in severe postpartum haemorrhage. We performed a pilot cluster-randomised controlled trial to evaluate the feasibility of a trial on early cryoprecipitate delivery in severe postpartum haemorrhage. Pregnant women (>24 weeks gestation), actively bleeding within 24 h of delivery and who required at least one unit of red blood cells were eligible. Women declining transfusion in advance or with inherited clotting deficiencies were not eligible. Four UK hospitals were randomly allocated to deliver either the intervention (administration of two pools of cryoprecipitate within 90 min of first red blood cell unit requested plus standard care), or the control group treatment (standard care, where cryoprecipitate is administered later or not at all). The primary outcome was the proportion of women who received early cryoprecipitate (intervention) vs. standard care (control). Secondary outcomes included consent rates, acceptability of the intervention, safety outcomes and preliminary clinical outcome data to inform a definitive trial. Between March 2019 and January 2020, 199 participants were recruited; 19 refused consent, leaving 180 for analysis (110 in the intervention and 70 in the control group). Adherence to assigned treatment was 32% (95%CI 23–41%) in the intervention group vs. 81% (95%CI 70–90%) in the control group. The proportion of women receiving cryoprecipitate at any time-point was higher in the intervention (60%) vs. control (31%) groups; the former had fewer red blood cell transfusions at 24 h (mean difference 0.6 units, 95%CI 1.2 to 0); overall surgical procedures (odds ratio 0.6, 95%CI 0.3–1.1); and intensive care admissions (odds ratio 0.4, 95%CI 0.1–1.1). There was no increase in serious adverse or thrombotic events in the intervention group. Staff interviews showed that lack of awareness and uncertainty about study responsibilities contributed to lower adherence in the intervention group. We conclude that a full-scale trial may be feasible, provided that protocol revisions are put in place to establish clear lines of communication for ordering early cryoprecipitate in order to improve adherence. Preliminary clinical outcomes associated with cryoprecipitate administration are encouraging and merit further investigation.Barts CharityJoint Research Management Office, Queen Mary University of Londo

    Using smart phones for deformations measurements of structures

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    The present work tests the suitability of using the digital cameras of smart phones for close range photogrammetry applications. For this purpose two cameras of smart phones Lumia 535 and Lumia 950 XL were used. The resolutions of the two cameras are 5 and 20 Mpixels respectively. The tests consist of (a) self calibration of the two cameras, (b) the implementation of close-range photogrammetry using the cameras of the two smart phones, theodolite intersection with LST method, and linear variable displacement transducers (LVDTs) for the measurement of vertical deflections, and (c) accuracy of photogrammetric determination of object space coordinates. The results of using Lumia 950 XL are much better than using Lumia 535 and are better or comparable to the results of theodolite intersection with least squares technique (LST). Finally, it can be stated that the digital cameras of smart phones are suitable for close range photogrammetry applications according to accuracy, costs and flexibility

    Optimization of graphene-based materials outperforming host epoxy matrices

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    The degree of graphite exfoliation and edge-carboxylated layers can be controlled and balanced to design lightweight materials characterized by both low electrical percolation thresholds (EPT) and improved mechanical properties. So far, this challenging task has been undoubtedly very hard to achieve. The results presented in this paper highlight the effect of exfoliation degree and the role of edge-carboxylated graphite layers to give self-assembled structures embedded in the polymeric matrix. Graphene layers inside the matrix may serve as building blocks of complex systems that could outperform the host matrix. Improvements in electrical percolation and mechanical performance have been obtained by a synergic effect due to finely balancing the degree of exfoliation and the chemistry of graphene edges which favors the interfacial interaction between polymer and carbon layers. In particular, for epoxy-based resins including two partially exfoliated graphite samples, differing essentially in the content of carboxylated groups, the percolation threshold reduces from 3 wt% down to 0.3 wt%, as the carboxylated group content increases up to 10 wt%. Edge-carboxylated nanosheets also increase the nanofiller/epoxy matrix interaction, determining a relevant reinforcement in the elastic modulus

    Reliability assessment of tidal stream energy: significance for large-scale deployment in the UK

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    This is the author accepted manuscript. The final version is available from CRC PressThe UK has ambitious plans to harness its available tidal stream resource, estimated at 95TWh/year by The Crown Estate (2013). The economic viability of large-scale deployments will be largely governed by aspects of plant availability, including reliability. Using available information on environmental parameters of (pre-) consented sites across the UK, this paper explores subassembly target reliability levels for tidal stream devices. Reliability models of devices are investigated to establish the influence of environmental site conditions with regard to underlying subassembly failure rates and target reliability levels. Hence, a relia-bility-focussed perspective on the planned deployments is presented

    Diagnosis and Management of Ureterovaginal Fistula in a Resource-Constrained Setting: Experience at a District Hospital in Northern Nigeria

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    During 2007 we were invited at different times to review and manage four women with ureterovaginal fistula following caesarean section performed in different rural hospitals. We describe our experience of a simple technique of diagnosis and management of these indigent patients in a resourceconstrained hospital. The condition was diagnosed by the three-swab test in all four patients, and abdominopelvic ultrasound was employed to help find the ureter involved. Transvesical ureteral implantation with a stent was carried out. Stent was removed after 2 weeks. All four patients were dry. Amidst the complexity of and sophistication of modern health care, it is important to remind ourselves of the common occurrence of this distressing condition following caesarean section and the use of a well known simple diagnostic technique and subsequent management in resource-poor communities Keywords: Ureterovaginal fistula, Caesarean section, Resource constrained Libyan Medical Journal Vol. 4 (1) 2009: pp. 45-4
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