Transport properties of electron swarms in tetrahydrofuran under the influence of an applied electric field

10 págs.; 14 figs.; PACS number(s): 34.80.−iUsing an almost complete set of electron impact cross sections for scattering from the important biomolecule tetrahydrofuran (THF), compiled as a part of this study, swarm transport coefficients are determined by solving the Boltzmann's equation over the range of applied reduced fields from 0.01 to 10 000 Td. The present investigation highlights the experimental issues associated with, and the real need for, measurements of the corresponding THF transport coefficients, so that the self-consistency of our proposed cross section set might be evaluated. © 2013 American Physical Society.theAustralian Academy of Science through its European Scientific Exchange Program, and the Spanish Ministerio de Economia y Productividad (Project FIS2012-32320). The experimental part was supported by Project No. PAPIIT IN 111611.Peer Reviewe

Dynamic Scaling and Two-Dimensional High-Tc Superconductors

There has been ongoing debate over the critical behavior of two-dimensional superconductors; in particular for high Tc superconductors. The conventional view is that a Kosterlitz-Thouless-Berezinskii transition occurs as long as finite size effects do not obscure the transition. However, there have been recent suggestions that a different transition actually occurs which incorporates aspects of both the dynamic scaling theory of Fisher, Fisher, and Huse and the Kosterlitz-Thouless-Berezinskii transition. Of general interest is that this modified transition apparently has a universal dynamic critical exponent. Some have countered that this apparent universal behavior is rooted in a newly proposed finite-size scaling theory; one that also incorporates scaling and conventional two-dimensional theory. To investigate these issues we study DC voltage versus current data of a 12 angstrom thick YBCO film. We find that the newly proposed scaling theories have intrinsic flexibility that is relevant to the analysis of the experiments. In particular, the data scale according to the modified transition for arbitrarily defined critical temperatures between 0 K and 19.5 K, and the temperature range of a successful scaling collapse is related directly to the sensitivity of the measurement. This implies that the apparent universal exponent is due to the intrinsic flexibility rather than some real physical property. To address this intrinsic flexibility, we propose a criterion which would give conclusive evidence for phase transitions in two-dimensional superconductors. We conclude by reviewing results to see if our criterion is satisfied.Comment: 14 page

Do precocial mammals develop at a faster rate? A comparison of rates of skull development in Sigmodon fulviventer and Mus musculus domesticus

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72993/1/j.1420-9101.2003.00568.x.pd

An exploration of the use of infant observation methods to research the identities of severely learning disabled adolescents and to enhance relationship-based practice for professional social work practice

This paper considers how infant observation methods may be adapted to explore and research the identities of severely learning disabled adolescents, a group of young people whose experiences are poorly represented in the literature. Through focusing on emotion and relationship, this ‘practice-near’ research method also offers a way for social workers to develop their reflective capacity in relation to the often hidden, uncomfortable emotions aroused by experiencing impairment and difference, but without the defences usually involved in assuming the professional role. The importance of taking time to get on a disabled child’s ‘wavelength’ is illustrated through extracts from the research which show how a young person’s agency and identity can be appreciated. The method also has the potential to develop social workers’ awareness of the powerful undercurrent of emotions apparent at times within families of severely disabled young people and tentative suggestions are made about the projective processes and hidden hostilities at work within one of the families observed as part of the research project. Professionals may be able to use this knowledge to become resilient and reflective practitioners and the observation method itself has something to offer by way of a containing experience for families

Conversations in a Crowded Room: An Assessment of the Contribution of Historical Research to Criminology

The relationship between history and social science generally, as well as history and criminology specifically, has long been considered problematic. But, since the likes of Burke (1992) and King (1999) spoke of a ‘dialogue of the deaf’, crime history has rapidly expanded and, more latterly, historical criminology has begun to emerge. This article reappraises the relationship of the subject areas by considering the impact that historical research has had on criminology. Although the impact is found to be somewhat patchy, the article identifies positive signs within the two fields that might point towards a more mutually‐enriching future

Changes in CO2 during ocean anoxic event 1d indicate similarities to other carbon cycle perturbations

Past greenhouse intervals of the Mesozoic were repeatedly punctuated by Ocean Anoxic Events (OAEs), major perturbations to the global carbon cycle and abrupt climate changes that may serve as relevant analogs for Earth’s greenhouse gas-forced climate future. The key to better understanding these transient climate disruptions and possible CO2 forced tipping-points resides in high-resolution, precise, and accurate estimates of atmospheric CO2 for individual OAEs. Here we present a high-temporal resolution, multi-proxy pCO2 reconstruction for the onset of mid-Cretaceous (Albian-Cenomanian Boundary) OAE1d. Coupling of pCO2 estimates with carbon isotopic compositions (δ13C) of charcoal, vitrain, and cuticle from the Rose Creek Pit (RCP), Nebraska, reveals complex phasing, including a lag between the well-documented negative δ13C excursion defining the onset of OAE1d and the CO2 increase. This lag indicates that increased CO2 or other C-based greenhouse gases may not have been the primary cause of the negative excursion. Our study reveals a pCO2 increase within the interval of the negative δ13C excursion, reaching a maximum of up to ~840 ppm (95% confidence interval -307 ppm/+167 ppm) toward its end. The reconstructed magnitude of CO2 increase (~357 ppm) is similar to that of Late Cretaceous OAE2 but of smaller magnitude than that of other major carbon cycle perturbations of the Mesozoic assessed via stomatal methods (e.g., the Toarcian OAE [TOAE], Triassic-Jurassic boundary event, Cretaceous-Paleogene Boundary event). Furthermore, our results indicate a possible shared causal or developmental mechanism with OAE1a and the TOAE