Characterization of bulk and surface currents in strain-balanced InGaAs quantum-well mesa diodes

We compare the electrical and optical characteristics of mesa diodes based on In0.62Ga0.38As/In0.45Ga0.55As strain-balanced multiple-quantum wells (SB-MQW) with lattice-matched (LM) In0.53Ga0.47As diodes. The dark current density of the SB-MQW devices is at least an order of magnitude lower than the LM devices for voltages >0.4 V. Sidewall recombination current is only measured on SB-MQW diodes when exposed to a damaging plasma. While radiative recombination current dominates in the SB-MQW diodes, it is less than the diffusive current in the LM diodes for the same applied voltage. (C) 2004 American Institute of Physics. (DOI:10.1063/1.1835537

High injection and carrier pile-up in lattice matched InGaAs/InP PN diodes for thermophotovoltaic applications

This article analyzes and explains the observed temperature dependence of the forward dark current of lattice matched In0.53Ga0.47As on InP diodes as a function of voltage. The experimental results show, at high temperatures, the characteristic current-voltage (I-V) curve corresponding to leakage, recombination, and diffusion currents, but at low temperatures an additional region is seen at high fields. We show that the onset of this region commences with high injection into the lower-doped base region. The high injection is shown by using simulation software to substantially alter the minority carrier concentration profile in the base, emitter and consequently the quasi-Fermi levels (QFL) at the base/window and the window/cap heterojunctions. We show that this QFL splitting and the associated electron "pile-up" (accumulation) at the window/emitter heterojunction leads to the observed pseudo-n=2 region of the current-voltage curve. We confirm this phenomenon by investigating the I-V-T characteristics of diodes with an InGaAsP quaternary layer (E-g=1 eV) inserted between the InP window (E-g=1.35 eV) and the InGaAs emitter (E-g=0.72 eV) where it serves to reduce the barrier to injected electrons, thereby reducing the "pile-up." We show, in this case that the high injection occurs at a higher voltage and lower temperature than for the ternary device, thereby confirming the role of the "accumulation" in the change of the I-V characteristics from n=1 to pseudo-n=2 in the ternary latticed matched device. This is an important phenomenon for consideration in thermophotovoltaic applications. We, also show that the activation energy at medium and high voltages corresponds to the InP/InGaAs conduction band offset at the window/emitter heterointerface

Quarantine Station North Head 1900-1984: a history of place

Theoretical thesis.Bibliography: pages 321-403.Introduction -- Section 1. A place of quarantine activity -- Chapter 1. North Head Quarantine Station : an overview of history and landscape at the turn of the century -- Chapter 2. Flashpoints : pandemics, an epidemic and the effects of war -- Chapter 3. Adapting to a changing environment, 1921-1984 -- Section 2. A working station -- Chapter 4. The rhythm of daily preparedness, 1912-1984 -- Chapter 5. The "forgotten" or "hidden" workforce, 1912-1984 -- Chapter 6. "Not in our backyard" : attempts at removal, 1881-1984 -- Section 3. A temporary place of refuge or respite -- Chapter 7. Those sheltered -- Chapter 8. Those detained -- Conclusion.In 1984 the Quarantine Station North Head – the oldest, largest and longest serving station in Australia - was closed and handed over to the New South Wales Government. In the following years the material degradation of the site threatened its survival, despite the promise of government funds to conserve its heritage value. After the site was leased to the heritage tourism group Mawland Hotel Management in 2006, it re-emerged as QSTATION, a retreat and conference facility where, via interactive experiences from dramatic performances and ghost tours, visitors could pay to learn something of the cultural and historical significance of the site. Packaged for public consumption and Mawland’s financial viability, the history of the station was compromised. Sandwiched between a ghoulish nineteenth century past which had little relevance to the station as a place of protection and work on the one hand, and a broader historiographical meta-narrative linking quarantine to policies, particularly in Australia and the Asia-pacific region, of restrictive immigration, nationhood, and white Australia, the twentieth century story, particularly the human face of quarantine is lost. This is exacerbated by the view that the station was in complete decline following the drop in maritime quarantines after the mid-1930s. Yet the twentieth century history of the site is a rich story of continued protective activity from the threat of disease, effective disinfection of imported goods and provision of temporary accommodation for diverse groups affected by war, natural disaster and immigration policies. This thesis aims to recover the twentieth century story by focussing on the history of the station as a history of place which allows us to consider the human face of quarantine in the built environment. Far from a ghostly site, the station was place of work, life and death, of shelter and refuge against the backdrop of some of the most important social and political changes in the nation’s twentieth century history.Mode of access: World wide web1 online resource ( 457 pages ) illustrations (some colour

Hidden fathers: an exploratory study of young single fathers at the margins.

Rapid social and demographic changes have brought about the diversity of family types including the presence of a significant number of lone-parent families. For the state as a whole just over 21 per cent (98,304) of all family units, where there is at least one dependent child under the age of 15, is headed by a lone-parent. For Limerick City the corresponding figure is 39 per cent (2,308). The equivalent statistic, for the parishes targeted by the PAUL Partnership is higher and ranges from 42 per cent in St Munchin's Parish to 63.9 per cent in Moyross Parish (Appendix A)

Uncertain futures: an exploratory study of men at the margins

Uncertain futures: an exploratory study of men at the margin

Making the links: towards an integrated strategy for the elimination of violence against women in intimate relationships with men: a study commissioned by Women's Aid

This main focus of the study is on women's experience of violence in intimate relationships with men i.e. husband, partner, ex husband or live-in partner, boyfriend. Domestic violence and violence in intimate relationships are used interchangeably. As such the study does not address issues relating to violence among siblings, violence between children and parents, violence in gay and lesbian relationships or violence by women against men. The main objectives of the study are: • To examine the extent of violence against women in intimate relationships; • To outline the extent to which services come in contact with the issue of violence against women in the home; • To document the professional and service response to women who have experienced violence; • In the light of the foregoing, to make recommendations regarding the development of services for women who have experienced violence in intimate relationships

Increases in plasma holotranscobalamin can be used to assess vitamin B-12 absorption in individuals with low plasma vitamin B-12

Low plasma concentrations of vitamin B-12 are common in Indians, possibly due to low dietary intakes of animal-source foods. Whether malabsorption of the vitamin contributes to this has not been investigated. A rise in the plasma holotranscobalamin (holo-TC) concentration after a standard dose of oral vitamin B-12 has been proposed as a measure of gastrointestinal absorption in people with normal plasma vitamin B-12 concentrations. We studied 313 individuals (children and parents, 109 families) in the Pune Maternal Nutrition Study. They received 3 doses of 10 µg (n = 191) or 2 µg (n = 122) of cyanocobalamin at 6-h intervals. A rise in plasma holo-TC of 15% and >15 pmol/L above baseline was considered normal vitamin B-12 absorption. The baseline plasma vitamin B-12 concentration was <150 pmol/L in 48% of participants; holo-TC was <35 pmol/L in 98% and total homocysteine was high in 50% of participants (>10 µmol/L in children and >15 µmol/L in adults). In the 10 µg group, the plasma holo-TC concentration increased by 4.8-fold from (mean ± SD) 9.3 ± 7.0 pmol/L to 53.8 ± 25.9 pmol/L and in the 2 µg group by 2.2-fold from 11.1 ± 8.5 pmol/L to 35.7 ± 19.3 pmol/L. Only 10% of the participants, mostly fathers, had an increase less than the suggested cut-points. Our results suggest that an increase in plasma holo-TC may be used to assess vitamin B-12 absorption in individuals with low vitamin B-12 status. Because malabsorption is unlikely to be a major reason for the low plasma vitamin B-12 concentrations in this population, increasing dietary vitamin B-12 should improve their status

Study Protocol: Prospective, observational, cohort study of COVID-19 in General Practice (North Dublin COVID-19 Cohort [‘ANTICIPATE’] Study)

Background: It is accepted that COVID-19 will have considerable long-term consequences, especially on people’s mental and physical health and wellbeing. Although the impacts on local communities have been immense, there remains little data on long term outcomes among patients with COVID-19 who were managed in general practice and primary care. This study seeks to address this knowledge gap by examining how the COVID-19 pandemic has impacted the medium and long-term health and wellbeing of patients attending general practice, especially their mental health and wellbeing. Methods: The study will be conducted at 12 general practices in the catchment area of the Mater Misericordiae University Hospital, i.e. the North Dublin area, an area which has experienced an especially high COVID-19 incidence. Practices will be recruited from the professional networks of the research team. A member of the general practice team will be asked to identify patients of the practice who attended the practice after 16/3/20 with a confirmed or presumptive diagnosis of COVID-19 infection. Potential participants will be provided with information on the study by the clinical team. Data will be collected on those patients who consent to participate by means of an interviewer-administered questionnaire and review of clinical records. Data will be collected on health (especially mental health) and wellbeing, quality of life, health behaviours, health service utilisation, and wider impacts of COVID-19 at recruitment and at two follow up time points (6, 12 months). Deliverables: The project involves collaboration with Ireland’s Health Service Executive, Ireland East Hospital Group, and the Mater Misericordiae University Hospital, Dublin. The study is funded by the Health Research Board. Findings will inform health policies that attenuate the adverse impacts of COVID-19 on population mental health and health generally.Health Research Board2021-08-31 JG: PDF replaced at authors' reques