491 research outputs found

    Assessing radiative transfer models trained by numerical weather forecasts using sun-tracking radiometric measurements for satellite link characterization up to W band

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    Radio communications, and in particular Earth-to-satellite links, are worldwide used for delivering digital services. The bandwidth demand of such services is increasing accordingly to the advent of more advanced applications (e.g., multimedia services, deep-space explorations, etc.) thus pushing the scientific community toward the investigation of channel carriers at higher frequencies. When using carrier frequencies above X band, the main drawback is how to tackle the impact of tropospheric processes (i.e., rain, cloud, water vapor). This work assesses the joint use of weather forecast models, radiative transfer models and Sun-tracking radiometric measurements to explore their potential benefits in predicting path attenuation and sky noise temperature for slant paths at frequencies between K and W band, thus paving the way to the optimization of satellite link-budgets

    Higher education and regional development - A case study of south east Ireland

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    The primary purpose of this study is to lest the hypothesis that a region without a university will be inevitably trapped in a Vicious spiral' of progressive relative decline both in local skills levels and in economic performance, i.e. that the lack of a university is an unsurmountable barrier to regional development. Research in the 1980s observed the connections between urban development and universities. analysed trends in the location of mobile industry, and in particular technology-based industry, and highlighted the apparent advantage to such industry in locating near to universities. Extensive university/industry interactions favourable to the fostering of local industrial clusters were indicated. Enthusiasm in the 1980s for the ' Silicon Valley ' model was superceded by the early 1990s by disenchantment with higher education as 'magic bullet' for all urban economic ills. iwt This thesis critically reviews this literature, and proceeds to examine the case of South East Ireland, a region with no university, against its findings. The presence of a steady supply of highly-skilled graduate employees is identified as the most critical factor which connects universities with industrial and other development. The processes which form the graduate sector of the workforce are therefore investigated both in the South East of Ireland and in a control case which has a university and science park, the Mid Western Region. Migration trends of students and graduates are investigated by means of interview and questionnaire. The results are analysed to determine their implications for the case study region's development potential. The main findings of the study are that, while empirical studies have not confirmed the idealised image of earlier research, the evidence nevertheless supports the view of the university as a pole of development. The most important contribution of the university to the development of its region is found to be in raising the skills level of the workforce The case study area is shown to have a profile of low participation and low graduate employment along with unemployment levels which are amongst the highest in Europe. This profile is correlated with the limited degree-level education provided within the area and is associated with a trend to progressive decline in relation to regions with universities. A programme of measures to enhance conditions for regional development is proposed

    <i>WhatsApp</i> use among African international distance education (IDE) students: transferring, translating and transforming educational experiences

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    Much of the research on how social media is embedded into the educational practices of higher education students has a Western orientation. In concentrating on a case study of the varied ways in which African International Distance Education (IDE) students actively use social media to shape their learning experiences, we discuss an under-researched group. The paper draws on analysis of 1295 online questionnaires and 165 in-depth interviews with IDE students at UNISA, South Africa, one of the largest providers of IDE globally. WhatsApp emerges as ‘the’ key social media tool that opens up opportunities for IDE students to transfer, translate and transform their educational journey when studying ‘at a distance’. Although WhatsApp does provide a ‘space of opportunity’ for some students, this is framed through socio-technical marginalisation, itself a reflection of demographic legacies of inequality. Exploring social media practices though the case of African IDE students places these students centre stage and adds to the awareness of the multiple centres from which international education is practiced

    Randomised controlled single-blind study of conventional versus depot mydriatic drug delivery prior to cataract surgery

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    BACKGROUND: A prerequisite for safe cataract surgery is an adequately dilated pupil. The authors conducted a trial to assess the efficacy (in terms of pupil diameter) of a depot method of pre-operative pupil dilatation, as compared with repeated instillations of drops (which is time-consuming for the nursing staff and uncomfortable for the patient). METHODS: A prospective randomised masked trial was conducted comprising 130 patients with no significant ocular history undergoing elective clear corneal phacoemulsification. 65 patients had mydriatic drops (Tropicamide 1%, Phenylephrine 2.5%, Diclofenac sodium 0.1%) instilled prior to surgery, 65 had a wick soaked in the same drop mixture placed in the inferior fornix. Horizontal pupil diameters were recorded on a millimetre scale immediately prior to surgery. RESULTS: There was no significant difference in pupil size between the two groups (p = 0.255, Student's t-test). CONCLUSION: There was no significant difference between the mydriasis obtained with the depot system compared with conventional drop application. Use of a depot mydriatic delivery system appears to be a safe and efficient method of drug delivery. TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number Register ISRCTN7804776

    How adolescents who cut themselves differ from those who take overdoses

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    The aims of this study were to identify in what ways adolescents who cut themselves differ from those who take overdoses, and to investigate the role of contagion in these behaviours. Data from an anonymous self-report questionnaire survey of 6,020 adolescents in 41 schools were analysed. Comparison of 220 adolescents who reported self-cutting in the previous year with 86 who had taken overdoses in the previous year as the sole method of deliberate self-harm (DSH) showed that far more of those who cut themselves had friends who had also engaged in DSH in the same period (OR 2.84, 95% CI 1.5–5.3, P < 0.001), and fewer had sought help from friends before cutting (OR 0.5, 95% CI 0.3–0.9, P < 0.02). Self-cutting usually involved less premeditation. Analyses at both the individual and school level showed that the association between engaging in DSH and exposure to DSH amongst peers was largely confined to girls who cut themselves. There are important differences between adolescents who cut themselves and those who take overdoses. Contagion may be an important factor in DSH by adolescents, especially in girls who cut themselves. These findings are relevant to the design of prevention and treatment programmes

    Self-harm in young people with perinatal HIV and HIV negative young people in England: cross sectional analysis.

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    BACKGROUND: Self-harm in adolescents is of growing concern internationally but limited evidence exists on the prevalence of self-harm in those living with HIV, who may be at higher risk of poor mental health outcomes. Therefore our aim was to determine the prevalence and predictors of self-harm among young people with perinatally-acquired HIV (PHIV) and HIV negative (with sibling or mother living with HIV) young people living in England. METHODS: 303 PHIV and 100 HIV negative young people (aged 12-23 years) participating in the Adolescents and Adults Living with Perinatal HIV cohort study completed an anonymous self-harm questionnaire, as well as a number of standardised mental-health assessments. Logistic regression investigated predictors of self-harm. RESULTS: The median age was 16.7 years in both groups, and 40.9% of the PHIV and 31.0% of the HIV negative groups were male. In total 13.9% (56/403) reported having ever self-harmed, with no difference by HIV status (p = 0.089). Multivariable predictors of self-harm were female sex (adjusted odds ratio (AOR) 5.3, (95% confidence interval 1.9, 14.1), p = 0.001), lower self-esteem (AOR 0.9 (0.8, 0.9) per 1 point increase, p < 0.001) and having ever used alcohol (AOR 3.8 (1.8, 7.8), p < 0.001). Self-esteem z-scores for both PHIV and HIV negative participants were 1.9 standard deviations below the mean for population norms. CONCLUSIONS: Self-harm is common among PHIV and HIV negative adolescents in England. Reassuringly however, they do not appear to be at an increased risk compared to the general adolescent population (15-19% lifetime prevalence). The low level of self-esteem (compared to available normative data) in both groups is worrying and warrants further attention

    Benign Orbital Tumors with Bone Destruction in Children

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    Purpose: To present rare benign orbital tumors with bone destruction in children who could not be diagnosed presurgically and may simulate malignant ones. Methods: A retrospective review of cases. Clinical, operative and pathological records in all children with a diagnosis of benign orbital tumors who showed remarkable bone destruction at a tertiary Ophthalmic Center in China between Jan 1, 2000 and Dec 31, 2009 were reviewed. All patients had definitive histopathologic diagnosis. Results: Eight patients with benign orbital tumors showed obvious bone destruction, including six cases of eosinophilic granuloma, one case of leiomyoma and one case of primary orbital intraosseous hemangioma. Among them, three patients were females and five patients were males. Tumors were unilateral in all cases, with both the right and left side affected equally. Age ranged from 3 to 7 years (mean 4.1 years). Symptom duration ranged from 1 to 5 weeks (mean 4.8 weeks). Eyelid swelling and palpable mass were the most common complaint. There was no evidence for multifocal involvement in cases with eosinophilic granuloma. Among six patients with eosinophilic granuloma, two were treated with low dose radiation (10 Gy), three received systemic corticosteroid and one was periodically observed only after incisional biopsy or subtotal curettage. There was no postoperative therapeutic intervention in the two patients with leiomyoma and intraosseous hemangioma. All eight patients regained normal vision without local recurrence after a mean follow-up time o

    Parenting, the other oldest profession in the world - a cross-sectional study of parenting and child outcomes in South Africa and Malawi.

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    Background Parenting quality is important in child development. In the presence of HIV poverty and life stress, parenting may be challenged and child development affected. Methods This study examines cross-sectional associations of situational factors such as poverty, mental health, HIV status, living with a biological parent, and stigma with good parenting and child outcomes (n=989; age=4-13 years) within the Child Community Care study (South Africa and Malawi). A parenting measure was created from 10 variables comprising 6 child and 4 parent ratings. These were highly correlated. Total parenting score was generated on a 10 point continuous scale, with a good parenting cut off then defined as >=8 out of a possible 10. Results Five factors were associated with good parenting. Positively associated with good parenting were being the biological parent of the child, parental mental health and dwelling in households with multiple adults. Poverty and stigma were negatively associated with good parenting. Using multiple mediation analysis, a positive direct effect of good parenting was found on child self-esteem, child behaviour and educational risks with a partial mediation via child depression and trauma. Conclusions These data highlight possible intervention points. Influences on parenting could be seen through being the biological parent, parental mental health, poverty and stigma. In these challenging environments, health, nutrition, mental health, education, and treatment to keep parents alive are all clearly identified as potential pathways to ensure child well-being. 19 </p

    Impulsivity and self-harm in adolescence: a systematic review

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    Research supports an association between impulsivity and self-harm, yet inconsistencies in methodology across studies have complicated understanding of this relationship. This systematic review examines the association between impulsivity and self-harm in community-based adolescents aged 11-25 years and aims to integrate findings according to differing concepts and methods. Electronic searches of EMBASE, MEDLINE, PsychINFO, CINAHL, PubMed and The Cochrane Library, and manual searches of reference lists of relevant reviews, identified 4,496 articles published up to July 2015, of which 28 met inclusion criteria. Twenty-four of the studies reported an association between broadly specified impulsivity and self-harm. However, findings varied according to the conception and measurement of impulsivity and the precision with which self-harm behaviours were specified. Specifically, lifetime non-suicidal self-injury was most consistently associated with mood-based impulsivity related traits. However, cognitive facets of impulsivity (relating to difficulties maintaining focus or acting without forethought) differentiated current self-harm from past self-harm. These facets also distinguished those with thoughts of self-harm (ideation) from those who acted on thoughts (enaction). The findings suggested that mood-based impulsivity is related to the initiation of self-harm, while cognitive facets of impulsivity are associated with the maintenance of self-harm. In addition, behavioural impulsivity is most relevant to self-harm under conditions of negative affect. Collectively, the findings indicate that distinct impulsivity facets confer unique risks across the life-course of self-harm. From a clinical perspective, the review suggests that interventions focusing on reducing rash reactivity to emotions or improving self-regulation and decision-making may offer most benefit in supporting those who self-harm
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