117 research outputs found
Picosecond laser ranging at wavelengths up to 2.4 ÎŒm using an InAs avalanche photodiode
Time-of-flight measurements using pulsed laser illumination in the wavelength region between 1.3 to 2.37 ÎŒm have been demonstrated with an InAs avalanche photodiode (APD). InAs is photo-sensitive at wavelengths up to 3.5 ÎŒm and with predominantly electron multipli- cation reducing detector noise, InAs APDs have clear potential for sen- sitive optical measurements of picosecond transients in the mid-wave infrared. Laboratory-based demonstrations of time-of-flight ranging using InAs APDs operated at room temperature is described
High-Gain InAs Planar Avalanche Photodiodes
We report the fabrication of InAs planar avalanche photodiodes (APDs) using Be ion implantation. The planar APDs have a low background doping of and large depletion widths approaching 8 ÎŒm. The thick depletion width enabled a gain of 330 to be achieved at â26 V at 200 K without inducing a significant tunneling current. No edge breakdown was observed within the APDs. The surface leakage current was found to be low with a gain normalized dark current density of 400 ÎŒAcmâ2 at â20 V at 200 K
Association of macro-level determinants with adolescent overweight and suicidal ideation with planning: A cross-sectional study of 21 Latin American and Caribbean Countries.
BackgroundAdolescents and young people (10-24 years old) in the Latin America and the Caribbean (LAC) region represent approximately 25% of the region's population. Since the 2008 global economic crisis, the pace of reduction in poverty and income inequality in the LAC region has stalled. The region is characterised by high levels of inequities and is also vulnerable to many natural disasters. Food systems are changing with increased availability and marketing of packaged and fast foods and sugar-sweetened drinks. Adolescence is a formative phase of the life course with multiple physical, emotional and social changes which can make them vulnerable to health problems. We assess the potential impact of macro-determinants, human and economic development as well as income inequality, on 2 top-ranking regional priorities for adolescent nutrition and mental health, using measures of overweight and suicidal ideation and planning which some have shown to be associated.Methods and findingsThe Global School-based Health Survey (GSHS) is a nationally representative self-administered, school-based survey. We examined overweight/obesity and suicidal ideation with planning by gross domestic product (GDP) per capita or human development index (HDI) in 10-19-year-old adolescents from 21 LAC countries between 2009 and 2013. Sample sizes varied from 943 in Anguilla to 27,988 in Argentina. A total of 55,295 adolescents had a measure of overweight/obesity status, and 59,061 adolescents reported about suicidal ideation with planning. There was equal representation by sex in the surveys (52% girls and 48% boys). A total of 28.8% of boys and 28.1% of girls had overweight/obesity, and 7.5% of boys and 17.5% of girls reported suicidal ideation with planning over the last 12 months. Adjusted for individual socioeconomic and risk behaviours, and relative to the highest GDP per capita tertile, the middle tertile was associated with 42% (95% confidence interval (CI) 59% to 17%, p = 0.003) and 32% (95% CI 60% to 5%, p = 0.023), and the lowest tertile with 40% (95% CI 55% to 19%, p = 0.001) and 46% (95% CI 59% to 29%, p ConclusionsThis study shows that economic and human development were positively associated with adolescent overweight/obesity but not with suicidal ideation with planning. We also observed an interconnectedness between overweight/obesity and suicide ideation with planning among girls. These findings highlight the importance of strategies that engage with both upstream and downstream determinants to improve adolescent nutrition and mental health
H-tailored surface conductivity in narrow band gap In(AsN)
We show that the n-type conductivity of the narrow band gap In(AsN) alloy can be increased within a thin (similar to 100 nm) channel below the surface by the controlled incorporation of H-atoms. This channel has a large electron sheet density of similar to 10(18) m(-2) and a high electron mobility (mu > 0.1 m(2)V(-1)s(-1) at low and room temperature). For a fixed dose of impinging H-atoms, its width decreases with the increase in concentration of N-atoms that act as H-traps thus forming N-H donor complexes near the surface. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License
Early intervention in Portugal: study of professionalsâ perceptions
Early intervention (EI) has been characterized by considerable advances in its domain, which has had great repercussions in the
implementation of the family-centered approach. These changes have had implications in the practices and in the adoption and learning of new values that should be implemented in EI. This study evaluates the professional perspectives regarding familycentered practices in EI programs in Portugal. The results highlight
the importance of effective collaboration and coordination between health, education, and social services and the importance of providing child and family support in a natural context. These results reinforce the need to invest in professional training to improve the
quality of services offered to families in EI.Fundação para a CiĂȘncia e a Tecnologia (FCT) no Ăąmbito do projecto PEst-OE/CED/UI1661/2014 do CIEd
Caseload midwifery as organisational change:the interplay between professional and organisational projects in Denmark
BACKGROUND: The large obstetric units typical of industrialised countries have come under criticism for fragmented and depersonalised care and heavy bureaucracy. Interest in midwife-led continuity models of care is growing, but knowledge about the accompanying processes of organisational change is scarce. This study focuses on midwivesâ role in introducing and developing caseload midwifery. Sociological studies of midwifery and organisational studies of professional groups were used to capture the strong interests of midwives in caseload midwifery and their key role together with management in negotiating organisational change. METHODS: We studied three hospitals in Denmark as arenas for negotiating the introduction and development of caseload midwifery and the processes, interests and resources involved. A qualitative multi-case design was used and the selection of hospitals aimed at maximising variance. Ten individual and 14 group interviews were conducted in spring 2013. Staff were represented by caseload midwives, ward midwives, obstetricians and health visitors, management by chief midwives and their deputies. Participants were recruited to maximise the diversity of experience. The data analysis adopted a thematic approach, using within- and across-case analysis. RESULTS: The analysis revealed a highly interdependent interplay between organisational and professional projects in the change processes involved in the introduction and development of caseload midwifery. This was reflected in three ways: first, in the key role of negotiations in all phases; second, in midwivesâ and managementâs engagement in both types of projects (as evident from their interests and resources); and third in a high capacity for resolving tensions between the two projects. The ward midwivesâ role as a third party in organisational change further complicated the process. CONCLUSIONS: For managers tasked with the introduction and development of caseload midwifery, our study underscores the importance of understanding the complexity of the underlying change processes and of activating midwivesâ and managersâ interests and resources in addressing the challenges. Further studies of female-dominated professions such as midwifery should offer good opportunities for detailed analysis of the deep-seated interdependence of professional and organisational projects and for identifying the key dimensions of this interdependence
Recommended from our members
Technologies of birth and models of midwifery care
This article is based on a study of a reform in the organisation of maternity services in the United Kingdom, which aimed towards developing a more woman-centred model of care. After decades of fragmentation and depersonalisation of care, associated with the shift of birth to a hospital setting, pressure by midwives and mothers prompted government review and a relatively radical turnaround in policy. However, the emergent model of care has been profoundly influenced by concepts and technologies of monitoring. The use of such technologies as ultrasound scans, electronic foetal monitoring and oxytocic augmentation of labour, generally supported by epidural anaesthesia for pain relief, have accompanied the development of a particular ecological model of birth â often called active management â, which is oriented towards the idea of an obstetric norm. Drawing on analysis of womenâs narrative accounts of labour and birth, this article discusses the impact on womenâs embodiment in birth, and the sources of information they use about the status of their own bodies, their labour and that of the child. It also illustrates how the impact on womenâs experiences of birth may be mediated by a relational model of support, through the provision of caseload midwifery care
Comparing the effect of STan (cardiotocographic electronic fetal monitoring (CTG) plus analysis of the ST segment of the fetal electrocardiogram) with CTG alone on emergency caesarean section rates: study protocol for the STan Australian Randomised controlled Trial (START).
BACKGROUND: Cardiotocography is almost ubiquitous in its use in intrapartum care. Although it has been demonstrated that there is some benefit from continuous intrapartum fetal monitoring using cardiotocography, there is also an increased risk of caesarean section which is accompanied by short-term and long-term risks to the mother and child. There is considerable potential to reduce unnecessary operative delivery with up to a 60% false positive diagnosis of fetal distress using cardiotocography alone. ST analysis of the fetal electrocardiogram is a promising adjunct to cardiotocography alone, and permits detection of metabolic acidosis of the fetus, potentially reducing false positive diagnosis of fetal distress. METHODS: This study will be a single-centre, parallel-group, randomised controlled trial, conducted over 3âyears. The primary hypothesis will be that the proportion of women with an emergency caesarean section on ST analysis will not equal that for women on cardiotocography monitoring alone. Participants will be recruited at the Women's and Children's Hospital, a high-risk specialty facility with approximately 5000 deliveries per annum. A total of 1818 women will be randomised to the treatment or conventional arm with an allocation ratio of 1:1, stratified by parity. The primary outcome is emergency caesarean section (yes/no). Statistical analysis will follow standard methods for randomised trials and will be performed on an intention-to-treat basis. Secondary maternal and neonatal outcomes will also be analysed. Additional study outcomes include psychosocial outcomes, patient preferences and cost-effectiveness. DISCUSSION: Approximately 20% of Australian babies are delivered by emergency caesarean section. This will be the first Australian trial to examine ST analysis of the fetal electrocardiogram as an adjunct to cardiotocography as a potential method for reducing this proportion. The trial will be among the first to comprehensively examine ST analysis, taking into account the impact on psychosocial well-being as well as cost-effectiveness. This research will provide Australian evidence for clinical practice and guideline development as well as for policy-makers and consumers to make informed, evidence-based choices about care in labour. TRIAL REGISTRATION: ANZCTR, ACTRN1261800006268 . Registered on 19 January 2018
Highly-mismatched InAs/InSe heterojunction diodes
We report on heterojunction diodes prepared by exfoliation and direct mechanical transfer of a p-type InSe thin film onto an n-type InAs epilayer. We show that despite the different crystal structures and large lattice mismatch (34%) of the component layers, the junctions exhibit rectification behaviour with rectification ratios of 10[superscript]4 at room temperature and broad-band photoresponse in the near infrared and visible spectral ranges
- âŠ