InAs/GaSb Tunnel Diodes

The Tunneling Field-Effect Transistor (TFET) has shown promise as a possible replacement for the MOSFET, especially in low power applications where power supplies continue to shrink. One of the biggest developmental challenges with the TFET is the relatively low drive current density compared to that of a MOSFET. Increasing tunneling probability will increase drive current density. Determining the peak current density in a tunnel diode can give insight into the tunneling probability for the material system. This can then be used to predict what material systems might support high current density TFETs. This study focuses on the InAs/GaSb broken gap system. Heterojunction Tunnel Diodes (HTDs) and Resonant Interband Tunnel Diodes (RITDs) were fabricated from Molecular Beam Epitaxy (MBE) grown substrates using varying doping concentrations, including undoped. The HTD devices were designed to investigate the effect doping has on peak current density. To determine a minimum current density, an undoped HTD was fabricated. The RITDs were designed to investigate an alternative structure and determine if it could be used to further improve peak current density. This study has shown that changes in dopant concentration only have a significant impact on tunneling current when the dopants are near the junction. No differences in current density was observed between the four HTD samples. The undoped sample exhibited an average peak current density of 16 kA/cm^2. The RITD samples did not show any significant differences in peak current density with varying well width. Additionally, the control HTD device performed significantly better, in terms of peak current density, than any of the RITD samples

Rational Vs Emotional Appeals with Communications to Landholders: A Review of Focus Group Responses

There are many organisations that seek to communicate with landholders for the purposes of engaging them in local environmental or conservation programs and sustainable production. This study examined whether different segments of landholders are likely to respond better to communication based on different appeals (rational or emotional), using different messages and communication channels. Seven hypothetical communication campaigns were designed with specific messages and appeals, each produced in three types of media. Focus groups of three specific landholder groups lifestylers., traditional and absentee landowners were held to obtain their responses to the campaigns. Findings suggest that the effectiveness of communications with landholders can be increased by using preferred messages and appeals, and selecting a combination of media appropriate to the landholder group being targeted

Over the Edge: Extending the duration of a reconsolidation intervention for spider fear

Pharmacologically disrupting fear memory reconsolidation dramatically reduces fear behaviour. For example, 2–3 min of tarantula exposure followed by 40 mg of propranolol HCl (i.e., a reconsolidation intervention) abruptly decreased spider avoidance, an effect that persisted one year later. However, the success of reconsolidation interventions is not guaranteed: Pavlovian fear-conditioning research shows that the window to target memory reconsolidation is small and easy to miss. If exposure is too long to trigger reconsolidation, but too short for extinction learning, an inactive transitional limbo state occurs, rendering the fear memory unchanged and insensitive to amnesic agents. In this pre-registered study, we aimed to find this behaviourally-controlled boundary condition. Spider-fearful participants underwent a ~3 min (n = 23) or ~14 min (n = 20) exposure to a tarantula, intended to trigger reconsolidation or the limbo state respectively, followed by 40 mg of propranolol. We expected greater spider fear reduction after 3 than 14 min of exposure. Unexpectedly, there were no group differences on any outcome measures. In both groups, Bayesian analysis revealed a marked reduction in fear behaviour towards a generalisation stimulus (a house spider) accompanied by lower self-reported distress, with a sharp decline in spider fear scores two days after treatment that persisted one year later. Possible explanations include that the boundary conditions of reconsolidation are wider in older and stronger memories than experimentally-induced fears, or that alternative processes caused the treatment effects. Although the mechanism is unclear, these results carry a tentative promising message for the potential of brief reconsolidation-targeting interventions to mitigate irrational fears

Strategies for coping with the costs of inpatient care: a mixed methods study of urban and rural poor in Vadodara District, Gujarat, India

Background In India, coping mechanisms for inpatient care costs have been explored in rural areas, but seldom among urbanites. This study aims to explore and compare mechanisms employed by the urban and rural poor for coping with inpatient expenditures, in order to help identify formal mechanisms and policies to provide improved social protection for health care

Risk factors of visceral leishmaniasis in East Africa: a case-control study in Pokot territory of Kenya and Uganda

BACKGROUND: In East Africa, visceral leishmaniasis (VL) is endemic in parts of Sudan, Ethiopia, Somalia, Kenya and Uganda. It is caused by Leishmania donovani and transmitted by the sandfly vector Phlebotomus martini. In the Pokot focus, reaching from western Kenya into eastern Uganda, formulation of a prevention strategy has been hindered by the lack of knowledge on VL risk factors as well as by lack of support from health sector donors. The present study was conducted to establish the necessary evidence-base and to stimulate interest in supporting the control of this neglected tropical disease in Uganda and Kenya. METHODS: A case-control study was carried out from June to December 2006. Cases were recruited at Amudat hospital, Nakapiripirit district, Uganda, after clinical and parasitological confirmation of symptomatic VL infection. Controls were individuals that tested negative using a rK39 antigen-based dipstick, which were recruited at random from the same communities as the cases. Data were analysed using conditional logistic regression. RESULTS: Ninety-three cases and 226 controls were recruited into the study. Multivariate analysis identified low socio-economic status and treating livestock with insecticide as risk factors for VL. Sleeping near animals, owning a mosquito net and knowing about VL symptoms were associated with a reduced risk of VL. CONCLUSIONS: VL affects the poorest of the poor of the Pokot tribe. Distribution of insecticide-treated mosquito nets combined with dissemination of culturally appropriate behaviour-change education is likely to be an effective prevention strategy

Human resources for health at the district level in Indonesia: the smoke and mirrors of decentralization

<p>Abstract</p> <p>Background</p> <p>In 2001 Indonesia embarked on a rapid decentralization of government finances and functions to district governments. One of the results is that government has less information about its most valuable resource, the people who provide the services. The objective of the work reported here is to determine the stock of human resources for health in 15 districts, their service status and primary place of work. It also assesses the effect of decentralization on management of human resources and the implications for the future.</p> <p>Methods</p> <p>We enumerated all health care providers (doctors, nurses and midwives), including information on their employment status and primary place of work, in each of 15 districts in Java. Data were collected by three teams, one for each province.</p> <p>Results</p> <p>Provider density (number of doctors, nurses and midwives/1000 population) was low by international standards – 11 out of 15 districts had provider densities less than 1.0. Approximately half of all three professional groups were permanent public servants. Contractual employment was also important for both nurses and midwives. The private sector as the primary source of employment is most important for doctors (37% overall) and increasingly so for midwives (10%). For those employed in the public sector, two-thirds of doctors and nurses work in health centres, while most midwives are located at village-level health facilities.</p> <p>Conclusion</p> <p>In the health system established after Independence, the facilities established were staffed through a period of obligatory service for all new graduates in medicine, nursing and midwifery. The last elements of that staffing system ended in 2007 and the government has not been able to replace it. The private sector is expanding and, despite the fact that it will be of increasing importance in the coming decades, government information about providers in private practice is decreasing. Despite the promise of decentralization to increase sectoral "decision space" at the district level, the central government now has control over essentially all public sector health staff at the district level, marking a return to the situation of 20 years ago. At the same time, Indonesia has changed dramatically. The challenge now is to envision a new health system that takes account of these changes. Envisioning the new system is a crucial first step for development of a human resources policy which, in turn, will require more information about health care providers, public and private, and increased capacity for human resource planning.</p

Variance component estimation uncertainty for unbalanced data: Application to a continent-wide vertical datum

Variance component estimation (VCE) is used to update the stochastic model in least-squares adjustments, but the uncertainty associated with the VCE-derived weights is rarely considered. Unbalanced data is where there is an unequal number of observations in each heterogeneous dataset comprising the variance component groups. As a case study using highly unbalanced data, we redefine a continent-wide vertical datum from a combined least-squares adjustment using iterative VCE and its uncertainties to update weights for each data set. These are: (1) a continent-wide levelling network, (2) a model of the ocean’s mean dynamic topography and mean sea level observations, and (3) GPS-derived ellipsoidal heights minus a gravimetric quasigeoid model. VCE uncertainty differs for each observation group in the highly unbalanced data, being dependent on the number of observations in each group. It also changes within each group after each VCE iteration, depending on the magnitude of change for each observation group’s variances. It is recommended that VCE uncertainty is computed for VCE updates to the weight matrix for unbalanced data so that the quality of the updates for each group can be properly assessed. This is particularly important if some groups contain relatively small numbers of observations. VCE uncertainty can also be used as a threshold for ceasing iterations, as it is shown—for this data set at least—that it is not necessary to continue time-consuming iterations to fully converge to unity

Towards a Critical Understanding of Music, Emotion and Self-Identity

The article begins by outlining a dominant conception of these relations in sociologically informed analysis of music, which sees music primarily as a positive resource for active self-making. My argument is that this conception rests on a problematic notion of the self and also on an overly optimistic understanding of music, which implicitly sees music as highly independent of negative social and historical processes. I then attempt to construct a) a more adequately critical conception of personal identity in modern societies; and b) a more balanced appraisal of music-society relations. I suggest two ways in which relations between self, music and society may not always be quite so positive or as healthy as the dominant conception suggests: 1) Music is now bound up with the incorporation of authenticity and creativity into capitalism, and with intensified consumption habits. 2) Emotional self-realisation through music is now linked to status competition. Interviews are analysed