796 research outputs found

    Energy saving market for mobile operators

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    Ensuring seamless coverage accounts for the lion's share of the energy consumed in a mobile network. Overlapping coverage of three to five mobile network operators (MNOs) results in enormous amount of energy waste which is avoidable. The traffic demands of the mobile networks vary significantly throughout the day. As the offered load for all networks are not same at a given time and the differences in energy consumption at different loads are significant, multi-MNO capacity/coverage sharing can dramatically reduce energy consumption of mobile networks and provide the MNOs a cost effective means to cope with the exponential growth of traffic. In this paper, we propose an energy saving market for a multi-MNO network scenario. As the competing MNOs are not comfortable with information sharing, we propose a double auction clearinghouse market mechanism where MNOs sell and buy capacity in order to minimize energy consumption. In our setting, each MNO proposes its bids and asks simultaneously for buying and selling multi-unit capacities respectively to an independent auctioneer, i.e., clearinghouse and ends up either as a buyer or as a seller in each round. We show that the mechanism allows the MNOs to save significant percentage of energy cost throughout a wide range of network load. Different than other energy saving features such as cell sleep or antenna muting which can not be enabled at heavy traffic load, dynamic capacity sharing allows MNOs to handle traffic bursts with energy saving opportunity.Comment: 6 pages, 2 figures, to be published in ICC 2015 workshop on Next Generation Green IC

    Spatial Distribution of the Incompressible Strips at Aharonov-Bohm Interferometer

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    In this work, the edge physics of an Aharonov-Bohm interferometer (ABI) defined on a two dimensional electron gas, subject to strong perpendicular magnetic field B, is investigated. We solve the three dimensional Poisson equation using numerical techniques starting from the crystal growth parameters and surface image of the sample. The potential profiles of etched and gate defined geometries are compared and it is found that the etching yields a steeper landscape. The spatial distribution of the incompressible strips is investigated as a function of the gate voltage and applied magnetic field, where the imposed current is confined to. AB interference is investigated due to scattering processes between two incompressible "edge-states".Comment: 5 pages, 3 figure

    Sustainable development of smallholder crop-livestock farming in developing countries

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    Meeting the growing demand for animal-sourced food, prompted by population growth and increases in average per-capita income in low-income countries, is a major challenge. Yet, it also presents significant potential for agricultural growth, economic development, and reduction of poverty in rural areas. The main constraints to livestock producers taking advantage of growing markets include; lack of forage and feed gaps, communal land tenure, limited access to land and water resources, weak institutions, poor infrastructure and environmental degradation. To improve rural livelihood and food security in smallholder crop-livestock farming systems, concurrent work is required to address issues regarding efficiency of production, risk within systems and development of whole value chain systems. This paper provides a review of several forage basedstudies in tropical and non-tropical dry areas of the developing countries. A central tenet of this paper is that forages have an essential role in agricultural productivity, environmental sustainability and livestock nutrition in smallholder mixed farming systems

    Schwannoma with an Uncommon Upper Lip Location and Literature Review

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    Schwannomas are usually single, encapsulated, and benign tumors of the nerve sheath that arise from the perineural Schwann cells. Schwannomas are mostly seen in the fourth decade. Despite its location in the head and neck region is 25–45%, lip location of schwannoma are very rare. We present a case of a upper lip schwannoma in the pediatric age and review the literature

    The effect of long-term feeding of conjugated linoleic acid on fertility in Japanese quail

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    The objective of this study was to determine the effects of the long-term feeding of conjugated linoleic acid (CLA) on laying hen performance, egg fertility and hatchability of fertile eggs of Japanese quail (Coturnix coturnix japonica). One hundred and sixty 7-day old Japanese quail chicks were randomly assigned to four groups (40 birds per group) and fed for five weeks on a commercial diet supplemented with either 0.5% hazelnut (Group A), 0.5% sunflower oil (Group B), 0.25% CLA (Group C) or 0.5% CLA (Group D). The birds received water and feed ad libitum during the study. At the end of the five weeks the birds were sexed, and 21 females and seven males from each group were selected. For a further six weeks these selected birds were fed a layer diet supplemented with their respective sources of oil. Eggs were collected daily and incubated weekly. The fertility rate was determined by visual inspection at the end of the incubation period. Dietary CLA at the inclusion level of 0.5%, but not at 0.25%, caused a significant decrease in percentage hatchability of the fertile eggs compared to Groups A and B. Hatchability of fertile eggs from Groups A, B, C and D was 74, 80, 72 and 70, respectively. Fertility rates between Groups A, B, C and D did not differ significantly, and were 64.4, 56.4, 66.0 and 62.8%, respectively. Hen-day egg production of Groups A, C and D were similar, but in weeks 3, 4, 5 and 6, hens in Group B had a significantly lower hen-day egg production (%) compared to Group A. Also, in weeks 3, 4, 5 and 6, egg size in Group B was significantly lower than that in the other groups. From this study it is concluded that dietary CLA at inclusion levels of 0.25% or 0.5% did not influence egg fertility, egg weight and egg production in Japanese quail. South African Journal of Animal Science Vol. 36(2) 2006: 99-10

    Higher-order aberrations following wavefront-guided photorefractive keratectomy and laser in situ keratomileusis

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    Background: We aimed to evaluate higher-order aberrations (HOAs) following wavefront-guided photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) in patients with myopia and myopic astigmatism. Methods: This retrospective observational case-control study included patients who underwent wavefront-guided PRK (40 eyes of 20 patients) or LASIK (40 eyes of 20 patients) between August 2018 and November 2018 at the refractive surgery unit of Kayseri City Hospital Eye Clinic, Turkey. The corrected distance visual acuity (CDVA), manifest refraction, corneal topography, and HOAs were evaluated preoperatively and 3 months postoperatively in all patients. Results: The mean age ± standard deviation (SD) was 27.13 ± 5.54 years and 29.10 ± 4.38 years in the PRK and LASIK groups, respectively (P = 0.06). Both groups had a mean CDVA of 1.00. The mean ± SD of spherical and spherical equivalent values was -2.09 ± 1.56 diopter (D) and -3.03 ± 1.72 D in the PRK group and -2.23 ± 1.69 D and -3.35 ± 1.71 D in the LASIK group, respectively (P = 0.58). When the preoperative and postoperative HOAs and root mean square (RMS) values (for a 6-mm pupil diameter) were compared in the PRK group, a significant difference was found in vertical coma and total RMS values (P = 0.003 and P ˂ 0.001, respectively); in the LASIK group, there was a significant difference in preoperative and postoperative vertical coma and total RMS values (P = 0.0.001 and P ˂ 0.001, respectively). There was no significant difference in preoperative and postoperative vertical coma values between the two groups (P = 0.735 and P = 0.583, respectively). Conclusions: In terms of HOAs, total RMS values decreased significantly and vertical coma values increased significantly at 3 months postoperatively in both PRK and LASIK groups. However, there were no differences between the two groups

    Examining the Mediating Role of Organisational Support on the Relationship between Organisational Cynicism and Turnover Intention in Technology Firms in Istanbul

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    Cynicism and turnover intentions are highlighted as being detrimental to organisations' sustainability. Drawing on the social exchange theory, this paper aims to examine the effect of organisational cynicism on turnover intention and the mediating role of organisational support on this relationship. A survey was conducted with 289 employees and managers. Data were gathered from 54 technology firms from Istanbul, Turkey, and analysed through structural equation modelling using AMOS. The findings suggest that the cognitive and affective dimensions of cynicism are significant predictors of turnover intention, and further that organisational support mediates the relationship between the cognitive and affective dimensions of cynicism and turnover intention. This research is novel in that it deepens our understanding of how detrimental workplace perceptions might affect employees' intentions to leave their organisations and to what extent organisational support mediates this relationship in technology firms in Istanbul, Turkey. To our knowledge, no study has investigated these three variables together, as in the proposed model

    The effects of community interventions on unplanned healthcare use in patients with multimorbidity: a systematic review

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    OBJECTIVES: To summarise the impact of community-based interventions for multimorbid patients on unplanned healthcare use. The prevalence of multimorbidity (co-existence of multiple chronic conditions) is rapidly increasing and affects one-third of the global population. Patients with multimorbidity have complex healthcare needs and greater unplanned healthcare usage. Community-based interventions allow for continued care of patients outside hospitals, but few studies have explored the effects of these interventions on unplanned healthcare usage. DESIGN: A systematic review was conducted. MEDLINE, EMBASE, PsychINFO and Cochrane Library online databases were searched. Studies were screened and underwent risk of bias assessment. Data were synthesised using narrative synthesis. SETTING: Community-based interventions. PARTICIPANTS: Patients with multimorbidity. MAIN OUTCOME MEASURES: Unplanned healthcare usage. RESULTS: Thirteen studies, including a total of 6148 participants, were included. All included studies came from high-income settings and had elderly populations. All studies measured emergency department attendances as their primary outcome. Risk of bias was generally low. Most community interventions were multifaceted with emphasis on education, self-monitoring of symptoms and regular follow-ups. Four studies looked at improved care coordination, advance care planning and palliative care. All 13 studies found a decrease in emergency department visits post-intervention with risk reduction ranging from 0 (95% confidencec interval [CI]: -0.37 to 0.37) to 0.735 (95% CI: 0.688-0.785). CONCLUSIONS: Community-based interventions have potential to reduce emergency department visits in patients with multimorbidity. Identification of specific successful components of interventions was challenging given the overlaps between interventions. Policymakers should recognise the importance of community interventions and aim to integrate aspects of these into existing healthcare structures. Future research should investigate the impact of such interventions with broader participant characteristics
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