Electrical determination of the valence-band discontinuity in HgTe-CdTe heterojunctions

Current-voltage behavior is studied experimentally in a Hg0.78Cd0.22Te-CdTe-Hg0.78Cd0.22Te heterostructure grown by molecular beam epitaxy. At temperatures above 160 K, energy-band diagrams suggest that the dominant low-bias current is thermionic hole emission across the CdTe barrier layer. This interpretation yields a direct determination of 390±75 meV for the HgTe-CdTe valence-band discontinuity at 300 K. Similar analyses of current-voltage data taken at 190–300 K suggest that the valence-band offset decreases at low temperatures in this heterojunction

Electrical studies of single-barrier Hg_(1-x)Cd_x Te heterostructures

We report an experimental study of the electrical properties of single‐barrier Hg_(1−x)Cd_xTe heterostructures grown by molecular‐beam epitaxy. At high temperature, the measured current is interpreted to be the sum of thermionic and tunneling hole currents. This analysis is applied to data from each of three samples, yielding values of the HgTe–CdTe valence‐band discontinuity between 290±50 and 390±75 meV at 300 K. In all three samples, data taken over the range 190–300 K are consistent with a valence‐band offset which decreases at lower temperatures. Current–voltage curves are taken at 4.2 K, yielding a novel single‐barrier negative differential resistance (NDR) due to electron tunneling. Theoretical simulations indicate that ΔE_v must be <100 meV at 4.2 K to produce NDR

The area-based social patterning of injuries among 10 to 19 year olds Changes over time in the Stockholm County

<p>Abstract</p> <p>Background</p> <p>Area-based studies of childhood injuries strongly suggest that neighborhood socio-demographic and economic circumstances impact on various – though not all – types of injuries. The primary aim of this study was to investigate the stability over time of the association between area characteristics and childhood injuries of various causes.</p> <p>Methods</p> <p>Register-based and ecological, the study encompassed Stockholm County's 138 parishes, and considered two time periods (1993–95; 2003–05). Two indices were measured: economic deprivation and social fragmentation, and parishes were allocated to their respective quintile on each index. Data on both unintentional and intentional injuries for children (boys and girls) aged 10–14 and 15–19 respectively were gathered from the County Council's hospital inpatient register. For each period and index, gender, age and cause-specific comparisons were made to assess the rate ratios (with 95% confidence intervals) of being injured using parishes belonging to the best index level as a comparison group. A series of simple and partial Pearson correlations were also calculated to assess the independent contribution of each index.</p> <p>Results</p> <p>Regardless of time period, there were rather few significant rate ratios and, when they occurred, there were both under and excess risks. For instance, in each period, boys from both age groups living in parishes with the highest levels of economic deprivation had lower rate of injury as a motor vehicle rider. Most strikingly, intentional injuries were more frequent during the second time period and in considerable excess among girls aged 15–19 from more economically deprived areas. Also, during that last period, none of the injury causes correlated significantly with the index of social fragmentation after adjustment for economic deprivation (partial correlation).</p> <p>Conclusion</p> <p>Over a ten-year period, differential economic deprivation among parishes has widened more than social fragmentation in Stockholm County. The correlation between those indices is high in both periods of time whilst the association between the levels of each index and injury rates varies depending on group of injuries or time period considered. It is of concern that intentional injuries have increased numerically and are significantly and positively correlated with economic deprivation (net of social fragmentation), in particular among girls.</p

Neoliberalism, managerialism and the reconfiguring of social work in Sweden and the United Kingdom

This is the author's manuscript of an article published in Archaeological Dialogues. http://dx.doi.org/10.1177/1350508412448222This paper considers some of the ways in which neoliberalism, through the processes of managerialism, has impacted on the occupation of social work in Sweden and the UK. It is argued that there are similar implications in both countries, through the managerial drive for increased performance in economy, efficiency and effectiveness, but also in the development of evidence based practice. Whilst the key focus of the paper is on similarities between these two countries, differences are also noted. There is also recognition of the way in which resistance to the reconfiguration of social work is taking shape