Some n-p (Hg,Cd)Te photodiodes for 8-14 micrometer heterodyne applications

The results describing the dc and CO2 laser heterodyne characteristics of a three element photodiode array and single element and four element photodiode arrays are presented. The measured data shows that the n(+)-p configuration is capable of achieving bandwidths of 475 to 725 MHz and noise equivalent powers of 3.2 x 10 to the minus 20th power W/Hz at 77 K and 1.0 x 10 to the minus 19th power W/Hz at 145 K. The n(+)-n(-)-p photodiodes exhibited wide bandwidths (approximately 2.0 GHz) and fairly good effective heterodyne quantum efficiencies (approximately 13-30 percent at 2.0 GHz). Noise equivalent powers ranging from 1.44 x 10 to the minus 19th power W/Hz to 6.23 x 10 to the minus 20th power W/Hz were measured at 2.0 GHz

Rat mammary carcinogenesis following neutron- or X-radiation

Female 61 to 63 - day - old Sprague-Dawley rats were exposed once to a single dose of either 0.43 - MeV neutrons or 250 - kVX - rays . For neutrons 23 rats were exposed in plastic tubes rotated around and 31 c m from a water-cooled tritium impregnated target bombarded with 2.45 - MeV protons from a V a n de Graaff generator. The mean kerma was measured at the rat location by integrating the response of a rat - sized homogeneous tissue equivalent ionization chamber of minimum mass. The ratio between absorbed dose and kerma is under investigation and is anticipated to be approximately 0.7. A compensated GM gamma-ray dosimeter indicated that the gamma - ray doses were 3.5% of the total dose. All rats were examined weekly for the presence of breast tumours and these were removed, fixed, stained and verified histologically as mammary neoplasms. At 10 months after exposure 98<7ο of the rats were a live . The neutron kerma, the per cent of rats with mammary neoplasia, and the number of rats were, respectively: 0.125 rads, 8.2°}o, 182; 0.5 rads, 9.0^0, 89; 2 rads, 20. 6,68; and 8 rads, 31.1%, 45. The X - ray results were: 30 R, 1.4% 95; 60 R, 27. l°Io, 48; and 90 R, 35.4%, 48. A 3. O^o incidence was found in 167 control rats. At 10 months after exposure the mammary neoplastic response after 8 rads of neutrons corresponds approximately to that after 60 - 90 R of X - rays . Similarly, the response after 2 rads of neutrons was intermediate between 30 and 60 R of X - rays and the response after 0 . 125 and 0.5 rads of neutrons was similar to that after 30 R of X - rays . This demonstrates that the RBE for 0.43 - MeV neutrons is much lower at high doses than at low doses. Determination of the confidence limits for the dose-RBE dependence and dose-incidence relationship will be determined as additional data are collected

A qualitative study into the use of formal services for dementia by carers from culturally and linguistically diverse (CALD) communities.

BACKGROUND: People with dementia and their family carers need to be able to access formal services in the community to help maintain their wellbeing and independence. While knowing about and navigating one's way through service systems is difficult for most people, it is particularly difficult for people from culturally and linguistically diverse (CALD) communities. This study addresses a lack of literature on the use of formal services for dementia by people from CALD backgrounds by examining the experiences and perceptions of dementia caregiving within four CALD communities - Italian, Chinese, Spanish and Arabic-speaking - in south western Sydney, Australia. METHODS: The study used a qualitative design and the methods included focus groups with family carers and one-to-one interviews with bilingual/bicultural community workers, bilingual general practitioners and geriatricians. A total of 121 family carers participated in 15 focus groups and interviews were held with 60 health professionals. All fieldwork was audiotaped, transcribed and subjected to thematic analysis. RESULTS: People from CALD communities are often unfamiliar with the concept of formal services and there may be strong cultural norms about maintaining care within the family, rather than relying on external services. CALD communities often have limited knowledge of services. There is a preference for services that will allow families to keep their relative at home, for safety as well as cultural reasons, and they are particularly reluctant to use residential care. While there is a preference for ethno-specific or multicultural services, mainstream services also need to ensure they are more flexible in providing culturally appropriate care. Positive outcomes occur when ethno-specific services work in partnership with mainstream programs. Dementia service providers need to develop a trusting relationship with their local CALD communities and promote their services in a way that is understandable and culturally acceptable to members of these communities. CONCLUSIONS: While members of CALD communities may have difficulties accessing formal services, they will use them if they are culturally and linguistically appropriate and can meet their needs. There are a number of ways to improve service provision to CALD communities and the responsibility for this needs to be shared by a range of stakeholders

Geographical variation in Hepatitis C-related severe liver disease and patient risk factors: A multicentre cross-sectional study

No abstract available

Geological controls on the geometry of incised-valley fills: Insights from a global dataset of late-Quaternary examples

Incised valleys that develop due to relative sea-level change are common features of continental shelves and coastal plains. Assessment of the factors that control the geometry of incised-valley fills has hitherto largely relied on conceptual, experimental or numerical models, else has been grounded on case studies of individual depositional systems. Here, a database-driven statistical analysis of 151 late-Quaternary incised-valley fills has been performed, the aim being to investigate the geological controls on their geometry. Results of this analysis have been interpreted with consideration of the role of different processes in determining the geometry of incised-valley fills through their effect on the degree and rate of river incision, and on river size and mobility. The studied incised-valley fills developed along active margins are thicker and wider, on average, than those along passive margins, suggesting that tectonic setting exerts a control on the geometry of incised-valley fills, likely through effects on relative sea-level change and river behaviour, and in relation to distinct characteristics of basin physiography, water discharge and modes of sediment delivery. Valley-fill geometry is positively correlated with the associated drainage-basin size, confirming the dominant role of water discharge. Climate is also inferred to exert a potential control on valley-fill dimensions, possibly through modulations of temperature, peak precipitation, vegetation and permafrost, which would in turn affect water discharge, rates of sediment supply and valley-margin stability. Shelves with slope breaks that are currently deeper than 120 m contain incised-valley fills that are thicker and wider, on average, than those hosted on shelves with breaks shallower than 120 m. No correlation exists between valley-fill thickness and present-day coastal-prism convexity, which is measured as the difference in gradient between lower coastal plains and inner shelves. These findings challenge some concepts embedded in sequence stratigraphic thinking, and have significant implications for analysis and improved understanding of source-to-sink sediment route-ways, and for attempting predictions of the occurrence and characteristics of hydrocarbon reservoirs

Child sexual abuse prevention: parental discussion, protective practices and attitudes

Understanding parental practices and attitudes regarding child sexual abuse (CSA) prevention could be used to improve CSA prevention, but little information is available. In this study, we summarise survey data collected from 248 Australian and UK parents (87% female) with at least one child aged 6-11 years (M = 8.6, SD = 1.8). This is the first study to quantify parental use of protective practices, other than prevention education, which may guard against CSA. Parental media mediation, which may safeguard against online dangers, was another unique focus of this study. Participants reported their discussion of sensitive topics with their children including CSA; behaviors that may reduce the incidence of CSA (e.g., monitoring, supervision, delegation of care and checking-in with the child); mediation of their child's media use; and attitudes towards CSA prevention education. Parents reported discussing sexual abuse less than other sensitive topics such as abduction dangers, drugs, and death but more than issues surrounding puberty, sex and pornography. Parents reported using high levels of protective behaviours, however some areas of concern were revealed. Of concern was the low-moderate level of parental media mediation, with substantial numbers of children potentially exposed to online risks such as using devices unsupervised in bedrooms or chatting to individuals unknown to their parents and not having their devices checked for concerning content. Almost all parents were supportive of CSA prevention education and felt they should provide this education. However, two-thirds of parents thought CSA education may be associated with harms for the child and two-thirds of parents believed children could prevent their own abuse. Reported results will aid in our understanding of which areas of parenting could be strengthened to create safer environments for children. This research has particularly highlighted the need for parents to be more protective around their children’s access to online devices

Predominant Asymmetrical Stem Cell Fate Outcome Limits the Rate of Niche Succession in Human Colonic Crypts.

Stem cell (SC) dynamics within the human colorectal crypt SC niche remain poorly understood, with previous studies proposing divergent hypotheses on the predominant mode of SC self-renewal and the rate of SC replacement. Here we use age-related mitochondrial oxidative phosphorylation (OXPHOS) defects to trace clonal lineages within human colorectal crypts across the adult life-course. By resolving the frequency and size distribution of OXPHOS-deficient clones, quantitative analysis shows that, in common with mouse, long-term maintenance of the colonic epithelial crypt relies on stochastic SC loss and replacement mediated by competition for limited niche access. We find that the colonic crypt is maintained by ~5 effective SCs. However, with a SC loss/replacement rate estimated to be slower than once per year, our results indicate that the vast majority of individual SC divisions result in asymmetric fate outcome. These findings provide a quantitative platform to detect and study deviations from human colorectal crypt SC niche homeostasis during the process of colorectal carcinogenesis.Wellcome Trus