Magnetic structure and glassiness in Fe 0.5 Ni 0.5 PS 3

This work explores the magnetic properties of Fe0.5Ni 0.5PS3. The system shows pronounced hysteresis in the magnetic phase transition temperature as a function of the direction of the change in temperature. Field cooled/zero field cooled hysteresis is not pronounced. However, the transition temperature between antiferromagnetic and paramagnetic order occurs at approximately 97 K on cooling, but at 138 K on warming, whether the warming is after zero field or field cooling. This is indicative of magnetic glassiness, and made all the more unusual because all measurements exhibit a transition to a third magnetic phase existing at temperatures below ∼14K. The intermediate phase relaxes on a laboratory time scale of the order of 48 min, into an antiferromagnetic state whose magnetic structure is, from neutron diffraction, indistinguishable from the low temperature state. This low temperature state shows magnetic ordering consistent with that observed in CoPS3 and NiPS3. Analysis of the neutron measurements shows that the direction of moments cannot be along the b-axis. It is also shown that the moments are unlikely to lie in the c * direction. Therefore, we suggest that the moments lie along the a-axis

Optimization and beam dynamics of a superconducting radio-frequency gun

Recent advances in superconducting radio-frequency (RF) technology and a better understanding of RF photoinjector design optimization make it possible to propose a specific design for a superconducting RF gun that can simultaneously produce both ultra-high peak brightness and high average current. Such a device is a critical component of next generation X-ray sources, such as self-amplified spontaneous emission free-electron lasers (SASE FEL) and energy recovery linac-based systems. The design presented in this paper is scaled from the present state-of-the-art normal conducting RF photoinjector that has been studied in the context of the linac coherent light source and SPARC SASE FEL injection schemes. Issues specific to the superconducing RF photoinjector, such as accelerating gradient limit, RF cavity and cryostat design, and compatibility with magnetic focusing and laser excitation of a photocathode are discussed

Evolving antimicrobial resistance in a patient receiving palliative OPAT for a vascular graft infection: a case report

Prosthetic vascular graft infection is devastating and frequently fatal. Cure requires removal of the graft and reperfusion by placement of a new graft. However, no evidence based guidelines exist for management where removal of the graft is not possible. We describe a patient who lived in a state of chronic infection suppression through outpatient parenteral antimicrobial therapy (OPAT) over a period of 32 months, and outline the challenges experienced and strategies used to suppress infection in the face of escalating antimicrobial resistance. To date there have been very few reports of OPAT used in the palliative context and this case illustrates the microbiological issues that can arise and the importance of the full OPAT multi-disciplinary team in managing these issues and optimising the patient's quality and length of life

Cablegation: III. Field Assessment of Performance

LOW rates into and out of furrows were monitored as a cablegation system irrigated a field. The resulting data were used to calculate furrow intake rates as a function of time. The initial supply rates to the furrows were within ± 13 percent of the designed flow rates. Seventy-eight percent of the variation was associated with deviations of the pipe elevation from the design grade. The computer model of this system predicts that deviations in flow rates resulting from elevation deviations will decrease as grade becomes steeper than the 0.28 percent used in this study. Seventy-three percent of the water applied to the field infiltrated. Intake opportunity times averaged 11.0 h at the top end and 8.3 h at the bottom. The furrow intake rate, Ir, was related to the average intake opportunity time, T, by the equation Ir = 48.6 + 214/T. From these data it can be calculated that water applications at the bottom of the field averaged 84 percent of the application at the top end. Runoff rate was relatively constant and total runoff was only about half of that which would have occurred under fixed set surface irrigation. Variability of furrow infiltration rates was high and 10 percent reduction in furrow supply rates would have resulted in water not reaching the ends of some furrows. In general, the cablegation system provides more uniform water application than is normally achieved with other surface irrigation systems. The automatic cutback in supply reduces runoff and the runoff is more easily reused because of its steady flow

The fossil record of early tetrapods: worker effort and the end-Permian mass extinction

It is important to understand the quality of the fossil record of early tetrapods (Tetrapoda, minus Lissamphibia and Amniota) because of their key role in the transition of vertebrates from water to land, their dominance of terrestrial faunas for over 100 million years of the late Palaeozoic and earlyMesozoic, and their variable fates during the end−Permian mass extinction. The first description of an early tetrapod dates back to 1824, and since then discoveries have occurred at a rather irregular pace, with peaks and troughs corresponding to some of the vicissitudes of human history through the past two centuries. As expected, the record is dominated by the well−sampled sedimentary basins of Europe and North America, but finds from other continents are increasing rapidly. Comparisons of snapshots of knowledge in 1900, 1950, and 2000 show that discovery of new species has changed the shape of the species−level diversification curve, contrary to earlier studies of family−level taxa. There is, however, little evidence that taxon counts relate to research effort (as counted by numbers of publications), and there are no biasing effects associated with differential study of different time intervals through the late Palaeozoic and Mesozoic. In fact, levels of effort are apparently not related to geological time, with no evidence that workers have spent more time on more recent parts of the record. In particular, the end−Permian mass extinction was investigated to determine whether diversity changes through that interval might reflect worker effort: it turns out that most records of early tetrapod taxa (when corrected for duration of geological series) occur in the Lower Triassic

The Collapse of Large Extra Dimensions

In models of spacetime that are the product of a four-dimensional spacetime with an ``extra'' dimension, there is the possibility that the extra dimension will collapse to zero size, forming a singularity. We ask whether this collapse is likely to destroy the spacetime. We argue, by an appeal to the four-dimensional cosmic censorship conjecture, that--at least in the case when the extra dimension is homogeneous--such a collapse will lead to a singularity hidden within a black string. We also construct explicit initial data for a spacetime in which such a collapse is guaranteed to occur and show how the formation of a naked singularity is likely avoided.Comment: Uses revtex

Differential improvements in lipid profiles and Framingham recurrent risk score in patients with and without diabetes mellitus undergoing long-term cardiac rehabilitation.

OBJECTIVE: To determine whether lipid profiles and recurrent coronary heart disease (CHD) risk could be modified in patients with and without diabetes mellitus undergoing long-term cardiac rehabilitation (CR). DESIGN: Retrospective analysis of patient case records. SETTING: Community-based phase 4 CR program. PARTICIPANTS: Patients without diabetes (n=154; 89% men; mean ± SD age, 59.6 ± 8.5y; body mass index [BMI], 27.0 ± 3.5 kg/m²) and patients with diabetes (n=20; 81% men; mean age, 63.0 ± 8.7y; BMI, 28.7 ± 3.3 kg/m²) who completed 15 months of CR. INTERVENTIONS: Exercise testing and training, risk profiling, and risk-factor education. MAIN OUTCOME MEASURES: Cardiometabolic risk factors and 2- to 4-year Framingham recurrent CHD risk scores were assessed. RESULTS: At follow up, a significant main effect for time was evident for decreased body mass and waist circumference and improved low-density lipoprotein cholesterol (LDL-C) level and submaximal cardiorespiratory fitness (all P<.05), showing the benefits of CR in both groups. However, a significant group-by-time interaction effect was evident for high-density lipoprotein cholesterol (HDL-C) level and total cholesterol (TC)/HDL-C ratio (both P<.05). TC/HDL-C ratio improved (5.0 ± 1.5 to 4.4 ± 1.3) in patients without diabetes, but showed no improvement in patients with diabetes (4.8 ± 1.6 v 4.9 ± 1.6). CONCLUSIONS: We showed that numerous anthropometric, submaximal fitness, and cardiometabolic risk variables (especially LDL-C level) improved significantly after long-term CR. However, some aspects of cardiometabolic risk (measures incorporating TC and HDL-C) improved significantly in only the nondiabetic group

Gendered endings: Narratives of male and female suicides in the South African Lowveld

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s11013-012-9258-y. Copyright @ Springer Science+Business Media, LLC 2012.Durkheim’s classical theory of suicide rates being a negative index of social solidarity downplays the salience of gendered concerns in suicide. But gendered inequalities have had a negative impact: worldwide significantly more men than women perpetrate fatal suicides. Drawing on narratives of 52 fatal suicides in Bushbuckridge, South Africa, this article suggests that Bourdieu’s concepts of ‘symbolic violence’ and ‘masculine domination’ provide a more appropriate framework for understanding this paradox. I show that the thwarting of investments in dominant masculine positions have been the major precursor to suicides by men. Men tended to take their own lives as a means of escape. By contrast, women perpetrated suicide to protest against the miserable consequences of being dominated by men. However, contra the assumption of Bourdieu’s concept of ‘habitus’, the narrators of suicide stories did reflect critically upon gender constructs

Cosmology of codimension-two braneworlds

We present a comprehensive study of the cosmological solutions of 6D braneworld models with azimuthal symmetry in the extra dimensions, moduli stabilization by flux or a bulk scalar field, and which contain at least one 3-brane that could be identified with our world. We emphasize an unusual property of these models: their expansion rate depends on the 3-brane tension either not at all, or in a nonstandard way, at odds with the naive expected dimensional reduction of these systems to 4D general relativity at low energies. Unlike other braneworld attempts to find a self-tuning solution to the cosmological constant problem, the apparent failure of decoupling in these models is not associated with the presence of unstabilized moduli; rather it is due to automatic cancellation of the brane tension by the curvature induced by the brane. This provides some corroboration for the hope that these models provide a distinctive step toward understanding the smallness of the observed cosmological constant. However, we point out some challenges for obtaining realistic cosmology within this framework.Comment: 30 pages, 4 figures; generalized result for nonconventional Friedmann equation, added referenc