468 research outputs found

    Time-Scale Domain Characterization of Time-Varying Ultrawideband Infostation Channel

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    The time-scale domain geometrical-based method for the characterization of the time varying ultrawideband (UWB) channel typical of an infostation channel is presented. Compared to methods that use Doppler shift as a measure of time-variation in the channel this model provides a more reliable measure of frequency dispersion caused by terminal mobility in the UWB infostation channel. Particularly, it offers carrier frequency independent method of computing wideband channel responses and parameters which are important for ultrawideband systems. Results show that the frequency dispersion of the channel depends on the frequency and not on the choice of bandwidth. And time dispersion depends on bandwidth and not on the frequency. It is also shown that for time-varying UWB, frame length defined over the coherence time obtained with reference to the carrier frequency results in an error margin which can be reduced by using the coherence time defined with respect to the maximum frequency in a given frequency band. And the estimation of the frequency offset using the time-scale domain (wideband) model presented here (especially in the case of multiband UWB frequency synchronization) is more accurate than using frequency offset estimate obtained from narrowband models

    INFLUENCE OF HEAD-TEACHERS CONFLICT MANAGEMENT STYLE ON TEACHERS’ JOB SATISFACTION IN PUBLIC SECONDARY SCHOOLS

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    The study focused on influence of head-teachers conflict management style on teachers’ job satisfaction in public secondary schools in Awka education zone of Anambra State, Nigeria. Two research questions guided the study and two null hypotheses were tested. A descriptive survey research design was adopted. The population of the study consisted 122 head-teachers in 61 public secondary schools in Awka education zone. No sample was taken, as the population size was manageable. A 16-items structured questionnaire validated by three experts was used for the study. The reliability of the instrument was ascertained using Pearson Product Moment Correlation Co-efficient to determine its degree of reliability which obtained overall reliability coefficient values of 0.95. Data related to the research questions were analyzed using mean and standard deviation while Analysis of Variance (ANOVA) was used to test the null hypotheses at 0.05 level of significance. The findings of the study revealed that respondents disagreed that head teachers use integrating conflict management style while they agreed in using obliging conflict management style for their job satisfaction. The study revealed that head teachers’ years of teaching experience does not affect the uses of integrating and obliging conflict management style in their job satisfaction. It was concluded that integrating conflict management style are rarely used by the head teacher. It was recommended, among others, that Head teachers should strive at minimizing conflicts and use appropriate methods to manage them such integrating either than obliging conflict management style.  Article visualizations

    Efficacy of galcanezumab in patients with migraine and history of failure to 3-4 preventive medication categories: subgroup analysis from CONQUER study

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    Background: Chronic migraine (CM) and episodic migraine (EM) are associated with substantial headache-related disability, poor quality of life and global societal burden. In this subgroup analysis from the CONQUER study, we report efficacy outcomes from a pre-specified analysis of galcanezumab versus placebo in patients with CM or EM and 3–4 prior preventive medication category failures due to inadequate efficacy (after at least 2 months at maximum tolerated dose), or safety or tolerability reasons. The patient population is of particular interest due to evidence of decreased quality of life and increased economic burden among patients with migraine that is inadequately managed and is of interest to decision-makers globally. Methods: Key outcomes included overall mean change from baseline in monthly migraine headache days and proportions of patients achieving ≥30% (CM), ≥50%, and ≥ 75% reduction (response rates) in monthly migraine headache days across Months 1–3. Patient functioning and disability were evaluated at Month 3. Results: Of the 462 randomized patients, 186 (40.3%) had a history of 3–4 preventive category failures. Galcanezumab versus placebo resulted in significantly (P ≤ .001) larger overall mean reduction in monthly migraine headache days (total: − 5.49 versus − 1.03; CM: − 6.70 versus − 1.56; EM: − 3.64 versus − 0.65). Similarly, the ≥50% response rate was significantly (P ≤ .001) higher with galcanezumab versus placebo (total: 41.0 versus 12.7; CM: 41.5 versus 8.4; EM: 41.1 versus 16.5). In the CM group, the ≥30% response rate was significantly higher in the galcanezumab group than the placebo group (CM, 57.5 versus 19.8, P ≤ .0001) as was the ≥75% response rate (13.3 versus 2.6, P ≤ .05). Galcanezumab also resulted in significant (P < .0001) improvements in patient functioning and reductions in disability. Conclusions: Galcanezumab was effective in a difficult-to-treat population of patients with CM or EM who had failed 3–4 prior preventive medication categories

    Label-free quantitative comparison of cerebrospinal fluid glycoproteins and endogenous peptides in subjects with Alzheimer's disease, mild cognitive impairment, and healthy individuals

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    PURPOSE: The goal of this study is to investigate putative molecular dynamic changes in cerebrospinal fluids (CSFs) collected from individuals with mild cognitive impairment (MCI) and Alzheimer's disease (AD) as compared to healthy controls. EXPERIMENTAL DESIGN: The CSF samples from 12 subjects comprised of four cognitively normal individuals and eight patients with MCI and AD, respectively. Two aliquots of each CSF samples (total 1 mL) of each participant are used for this study. Endogenous peptide separations are performed using 10 000 molecular weight cut-off filters followed by LC-MS/MS identification and quantitation while lectin-enrichment chromatography is used to enrich glycoproteins in CSF followed by trypsin digestion and subsequent LC-MS/MS for shotgun identification and label-free quantitation. RESULTS: Using an optimized submicrogram peptide separation with molecular weight cut-off filtration and an in house-constructed database, 645 peptides are identified. Glycoproteins are enriched by lectin affinity chromatography, resulting in 795 identified proteins. The discovery and alterations of proSAAS-derived peptides and transthyretin are described and their roles in AD are discussed. CONCLUSIONS AND CLINICAL RELEVANCE: Comprehensive identification of endogenous CSF peptidome is achieved. Fifteen proteins are found to be differentially expressed among the three groups. The dynamic changes of transthyretin are reported for the first time

    Performance analysis of an optical packet switch with shared parametric wavelength converters

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    Potentiality of Diethylamine as Agent of Deproteination and Deacetylation in the Extraction of Chitosan from Scylla serrata Shell

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    The potentiality of diethylamine as deproteination and deacetylation agent in the extraction of chitosan from Scylla serrata (giant mud crab) shell was investigated. The aim was to find an alternative agent to inorganic alkalis as possible replacement for use in the production of high quality chitosan with the right stability. Pretreatment of the shell was carried out and followed by demineralization using hydrochloric acid. Diethylamine was used for deproteination and deacetylation by modifying some published protocols. Moisture, ash, fat and protein contents of the extracts were determined using their respective standard methods. Fourier Transform Infrared (FTIR) technique was used for spectroscopic analysis. Scylla serrata shell was composed of 14.25% protein, 32.84% mineral (CaCO3), 31.52% chitin and 21.39% chitosan. Moisture, ash, fat and protein contents of chitin extracted from Scylla serrata shell were 2.35%, 3.03%, 1.79% and 3.85% respectively while those of chitosan were 1.65%, 3.84%, 0.53% and 2.80% respectively. Degree of deacetylation (DDA) and carbon to nitrogen ratio were 69.24% and 5.67 respectively. FTIR spectra of the extracted chitin and chitosan from Scylla serrata showed the presence of some active compounds of carbonyl, amide, amine and hydroxyl groups. However, CH3 waging along chain (952 cm-1), CO stretching at 1026 cm-1 and 1073 cm-1, and amide II band (1563 cm-1) were not found in the extracted chitin while HPO42- and amide III were also not found in the extracted chitosan. These moieties were present in the standard chitin and chitosan respectively. This study has shown that diethylamine (organic base) has great potential as agent of deproteination and deacetylation in the extraction of chitosan from Scylla serrata. Consequently, academic activity in the area of investigation of the stability of the extracted chitosan from Scylla serrata using diethylamine as deproteination and deacetylation agent is strongly recommended. Keywords: Diethylamine, deproteination, deacetylation, chitin and chitosan, Scylla serrata shell. DOI: 10.7176/CMR/12-7-07 Publication date:October 31st  2020

    Evaluation of the Nigerian national antiretroviral (ARV) treatment training programme

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    There is an understanding that greater availability of HIV treatment for the 40.3 million people currently infected with HIV is a humanitarian imperative that could prolong the lives of millions, restore economic productivity, and stabilise societies in some of the world's hardest-hit regions. The Nigerian government recognises that the country has the third highest burden of infection, with people living with HIV estimated to total 4.0 million, and so in 2002 commenced the implementation of one of Africa's largest antiretroviral (ARV) treatment programmes. A successful ARV programme requires that all components of a functional management system be put in place for effective and efficient functioning. This would include logistics, human resources, financial planning, and monitoring and evaluation systems, as well as sustainable institutional capacities. The Nigerian national ARV treatment training programme was conceived to meet the human resource needs in hospitals providing ARV therapy. This paper reports on the evaluation of the training programme. It examines knowledge and skills gained, and utilisation thereof. Recommendations are made for improved training effectiveness and for specific national policy on training, to meet the demand for scaling up therapy to the thousands who need ARV. Keywords: ARV, training, evaluation, HIV, health care providerJournal of Social Aspects of HIV/AIDS Research Initiatve Vol. 3 (3) 2006: pp. 488-50

    The safety of paediatric surgery between COVID-19 surges:an observational study

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    Despite the ongoing coronavirus disease 2019 (COVID-19) pandemic, elective paediatric surgery must continue safely through the first, second and subsequent waves of disease. This study presents outcome data from a children's hospital in north-west England, the region with the highest prevalence of COVID-19 in England. Children and young people undergoing elective surgery isolated within their household for 14 days, then presented for real-time reverse transcriptase polymerase chain reaction testing for severe acute respiratory syndrome coronavirus disease-2 (SARS-CoV-2) within 72 h of their procedure (or rapid testing within 24 h in high-risk cases), and completed a screening questionnaire on admission. Planned surgery resumed on 26 May 2020; in the four subsequent weeks, there were 197 patients for emergency and 501 for elective procedures. A total of 488 out of 501 (97.4%) elective admissions proceeded, representing a 2.6% COVID-19-related cancellation rate. There was no difference in the incidence of SARS-CoV-2 among children and young people who had or had not isolated for 14 days (p > 0.99). One out of 685 (0.1%) children who had surgery re-presented to the hospital with symptoms potentially consistent with SARS-CoV-2 within 14 days of surgery. Outcomes were similar to those in the same time period in 2019 for length of stay (p = 1.0); unplanned critical care admissions (p = 0.59); and 14-day hospital re-admission (p = 0.17). However, the current cohort were younger (p = 0.037); of increased complexity (
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