1,095 research outputs found
Enhancing the Performance of Low Priority SUs Using Reserved Channels in CRN
Cognitive radio networks (CRNs) are considered a promising solution for
spectrum resources scarcity and efficient channel utilization. In this letter,
multi-dimensional analytical Markov model based on reservation channel access
scheme and channel aggregation method is proposed to enhance spectrum
utilization, capacity of low priority secondary users (SUs) and reducing
handoff probability of SUs. Moreover, the proposed method improves the
performance of high priority SUs by providing the capability to resume the
connection after dropping. The numerical results indicate that the modified
reservation access model can enhance the performance of SUs compared to the
traditional basic random access model
Homology and symmetry breaking in Rayleigh-Benard convection: Experiments and simulations
Algebraic topology (homology) is used to analyze the weakly turbulent state
of spiral defect chaos in both laboratory experiments and numerical simulations
of Rayleigh-Benard convection.The analysis reveals topological asymmetries that
arise when non-Boussinesq effects are present.Comment: 21 pages with 6 figure
Safety and efficacy analysis of microwave ablation in small hepatocellular carcinomas sized below 3 cm
Purpose: The aim of this study was to investigate the efficacy and safety of microwave ablation (MWA) in small hepatocellular carcinomas sized ≤ 3 cm, determine long-term survival, and identify prognostic factors for survival rates. Material and methods: In this study, the radiological and laboratory findings obtained from 31 consecutive patients who underwent MWA were retrospectively evaluated. The survival periods and complication rates were analysed. Results: Microwave ablation was applied to 42 hepatocellular carcinoma nodules in 31 patients. The mean age of the patients was 61 ± 7.3 (median 62, range 46-78) years. The mean overall survival (OS) was 47.4 ± 3.3 months. The rates of cumulative OS in the first, second, and third years were 95.2%, 91.8%, and 79.2%, respectively. The mean disease-free survival (DFS) rate was 24.1 ± 2.5 months. The cumulative DFS rates in the first, second, and third years were 75.6%, 52.5%, and 28.2%, respectively. The number of tumours and tumour distribution were determined as prognostic factors. No major complication was detected, but six patients (13.9%) developed minor complications after MWA. Conclusions: Microwave ablation in patients with hepatocellular carcinoma is a safety treatment modality with very low rates of complications. It offers an effective treatment with a high rate of complete response and local disease control according to the short-term results. In the long term, it prolongs the survival time of the treated patients. The number of tumours and tumour distribution were determined as prognostic factors affecting survival rates
SmartAbility: Detection of reduced physical abilities through smartphone sensors
This paper describes a developed Android application to accompany the SmartAbility Framework,
in order to recommend technologies for people with reduced physical ability. The framework is a
culmination of previously conducted research, including requirements elicitation and technology
trials. The application is based on a previous prototype version that required manual input of user
abilities. The presented version detects the action that users are able to perform independently
through the adoption of sensor technologies that are built-into Android devices, such as the
accelerometer and step counter. The knowledge contained within the framework is subsequently
used to derive recommendations of technology that could be suitable for the user. Future
enhancements to the application will enable complete automatic detection, without the requirement
for manual input. The exploitation of the SmartAbility application is anticipated to increase
technology awareness amongst the user community, as well as providing a means for assistive
technology manufacturers to promote their products
Conceptualising and Modelling E-Recruitment Process for Enterprises through a Problem Oriented Approach
Internet-led labour market has become so competitive it is forcing many organisations from different sectors to embrace e-recruitment. However, realising the value of the e-recruitment from a Requirements Engineering (RE) analysis perspective is challenging. This research was motivated by the results of a failed e-recruitment project conducted in military domain which was used as a case study. After reviewing the various challenges faced in that project through a number of related research domains, this research focused on two major problems: (1) the difficulty of scoping, representing, and systematically transforming recruitment problem knowledge towards e-recruitment solution specification; and (2) the difficulty of documenting e-recruitment best practices for reuse purposes in an enterprise recruitment environment. In this paper, a Problem-Oriented Conceptual Model (POCM) with a complementary Ontology for Recruitment Problem Definition (Onto-RPD) is proposed to contextualise the various recruitment problem viewpoints from an enterprise perspective, and to elaborate those problem viewpoints towards a comprehensive recruitment problem definition. POCM and Onto-RPD are developed incrementally using action-research conducted on three real case studies: (1) Secureland Army Enlistment; (2) British Army Regular Enlistment; and (3) UK Undergraduate Universities and Colleges Admissions Service (UCAS). They are later evaluated in a focus group study against a set of criteria. The study shows that POCM and Onto-RPD provide a strong foundation for representing and understanding the e-recruitment problems from different perspectives
Cost effectiveness of strategies to combat road traffic injuries in sub-Saharan Africa and South East Asia: mathematical modelling study
Objective To identify and estimate the population costs and effects of a selected set of enforcement strategies for reducing the burden of road traffic injuries in developing countries
Characterization and inhibition studies of an α-carbonic anhydrase from the endangered sturgeon species Acipenser gueldenstaedti.
An α-carbonic anhydrase (CA, EC 4.2.1.1) was purified and characterized kinetically from erythrocytes of the sturgeon Acipenser gueldenstaedti, an endangered species. The sturgeon enzyme (AgCA) showed kinetic parameters for the CO(2) hydration reaction comparable with those of the human erythrocytes enzyme hCA II, being a highly active enzyme, whereas its esterase activity with 4-nitrophenyl acetate as substrate was lower. Sulphonamide inhibitors (acetazolamide, sulphanilamide) strongly inhibited AgCA, whereas metal ions (Ag(+), Zn(2+), Cu(2+) and Co(2+)) were weak, millimolar inhibitors. Several widely used pesticides (2,4-dichlorophenol, dithiocarbamates, parathion and carbaryl) were also assayed as inhibitors of this enzyme. The dithiocarbamates were low micromolar AgCA inhibitors (IC(50) of 16-18 μM), whereas the other pesticides inhibited the enzyme with IC(50)s in the range of 102-398 μM. The wide use of dithiocarbamate pesticides may be one of the factors enhancing the vulnerability of this sturgeon species to pollutants
Evidence-based prescribing: combining network meta-analysis with multicriteria decision analysis to choose among multiple drugs
What is the drug of choice for condition x? is among the most commonly asked questions in primary care.1 Reflecting the complexity of prescribing decisions, answering this question requires a difficult trade-off between the benefits and harms of multiple drugs for a given condition. The principles of evidence-based medicine suggest that prescribing decisions should be guided by an objective benchmark, namely scientific evidence.2 Such evidence is particularly important when choosing a first-line treatment among multiple alternatives. Unfortunately, existing clinical evidence on benefits and harms is rarely adequate to inform prescribing decisions. A randomized controlled trial comparing all relevant drugs would provide such information. However, clinical trials are often designed for regulatory purposes and, therefore, include selective patient populations and do not include all available comparator drugs.3,4 To obtain insight into the comparative benefits and harms of multiple drugs, prescribers turn to summaries of evidence to discern the most promising drugs from their less effective comparators. Recent methods used to synthesize existing evidence provide much-needed information on the comparative benefits and harms of multiple drugs. Network meta-analysis is one such method that allows for the combination of direct and indirect evidences from randomized trials, facilitating the comparison of all relevant drugs even when they are not directly compared with each other in clinical trials.5 The recent surge in the number of network meta-analyses in the general medical literature is a testament to the increasing need for comparative evidence in prescribing decisions
A review on laser-induced crystallization from solution
Crystallization is abound in nature and industrial practice. A plethora of
indispensable products ranging from agrochemicals and pharmaceuticals to
battery materials, are produced in crystalline form in industrial practice.
Yet, our control over the crystallization process across scales, from molecular
to macroscopic, is far from complete. This bottleneck not only hinders our
ability to engineer the properties of crystalline products essential for
maintaining our quality of life but also hampers progress toward a sustainable
circular economy in resource recovery. In recent years, approaches leveraging
light fields have emerged as promising alternatives to manipulate
crystallization. In this review article, we classify laser-induced
crystallization approaches where light-material interactions are utilized to
influence crystallization phenomena according to proposed underlying mechanisms
and experimental setups. We discuss non-photochemical laser-induced nucleation,
high-intensity laser-induced nucleation, laser trapping-induced
crystallization, and indirect methods in detail. Throughout the review, we
highlight connections amongst these separately evolving sub-fields to encourage
interdisciplinary exchange of ideas.Comment: V. Korede and N. Nagalingam contributed equally to this wor
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