Ferroelectricity in strained Ca0.5_{0.5}Sr0.5_{0.5}TiO3_3 from first principles

We present a density functional theory investigation of strained Ca$_{0.5}$Sr$_{0.5}$TiO$_3$. We have determined the structure and polarization for a number of arrangements of Ca and Sr in a 2$\times$2$\times$2 supercell. The a and b lattice vectors are strained to match the lattice constants of the rotated Si(001) face. To set the context for the CSTO study, we also include simulations of the Si(001) constrained structures for CaTiO$_3$ and SrTiO$_3$. Our primary findings are that all Ca$_{0.5}$Sr$_{0.5}$TiO$_3$ structures examined except one are ferroelectric, exhibiting polarizations ranging from 0.08 C/m$^2$ for the lowest energy configuration to about 0.26 C/m$^2$ for the higher energy configurations. We find that the configurations with larger polarizations have lower c/a ratios. The net polarization of the cell is the result of Ti-O ferroelectric displacements regulated by A-site cations.Comment: 13 pages, 4 figure

A Cytological Study of the Induced Octoploid of an Agropyron-Hordeum Hybrid

The occurrence of hybrids, both interspecific and intergeneric, is frequent in the Gramineae generally (Stebbins, 1949), and is especially common in the tribe Hordeae of which both A. trachycaulum and H. jubatum are members. Intergeneric hybrids in this tribe have been studied by Stebbins et al. (1946a, and 1946b), Stebbins and Walters (1949), and Stebbins and Singh (1950) in an effort to determine true phylogenetic relationships on which to base a taxonomic classification, and results of these studies have indicated that the current taxonomic treatment of this tribe is highly artificial. Attempts to produce a perennial wheat and improve forage grasses has lent additional stimulus to the study of crosses in the Hordeae. An excellent discussion and literature review on these studies is given by Myers (1947). (1947)

Patient safety and estimation of renal function in patients prescribed new oral anticoagulants for stroke prevention in atrial fibrillation

OBJECTIVE: In clinical trials of dabigatran and rivaroxaban for stroke prevention in atrial fibrillation (AF), drug eligibility and dosing were determined using the Cockcroft-Gault equation to estimate creatine clearance as a measure of renal function. This cross-sectional study aimed to compare whether using estimated glomerular filtration rate (eGFR) by the widely available and widely used Modified Diet in Renal Disease (MDRD) equation would alter prescribing or dosing of the renally excreted new oral anticoagulants. PARTICIPANTS: Of 4712 patients with known AF within a general practitioner-registered population of 930 079 in east London, data were available enabling renal function to be calculated by both Cockcroft-Gault and MDRD methods in 4120 (87.4%). RESULTS: Of 4120 patients, 2706 were <80 years and 1414 were ≥80 years of age. Among those ≥80 years, 14.9% were ineligible for dabigatran according to Cockcroft-Gault equation but would have been judged eligible applying MDRD method. For those <80 years, 0.8% would have been incorrectly judged eligible for dabigatran and 5.3% would have received too high a dose. For rivaroxaban, 0.3% would have been incorrectly judged eligible for treatment and 13.5% would have received too high a dose. CONCLUSIONS: Were the MDRD-derived eGFR to be used instead of Cockcroft-Gault in prescribing these new agents, many elderly patients with AF would either incorrectly become eligible for them or would receive too high a dose. Safety has not been established using the MDRD equation, a concern since the risk of major bleeding would be increased in patients with unsuspected renal impairment. Given the potentially widespread use of these agents, particularly in primary care, regulatory authorities and drug companies should alert UK doctors of the need to use the Cockcroft-Gault formula to calculate eligibility for and dosing of the new oral anticoagulants in elderly patients with AF and not rely on the MDRD-derived eGFR

Polymerizing the fibre between bacteria and host cells: the biogenesis of functional amyloid fibres

Amyloid fibres are proteinaceous aggregates associated with several human diseases, including Alzheimer's, Huntington's and Creutzfeldt Jakob's. Disease-associated amyloid formation is the result of proteins that misfold and aggregate into β sheet-rich fibre polymers. Cellular toxicity is readily associated with amyloidogenesis, although the molecular mechanism of toxicity remains unknown. Recently, a new class of ‘functional’ amyloid fibres was discovered that demonstrates that amyloids can be utilized as a productive part of cellular biology. These functional amyloids will provide unique insights into how amyloid formation can be controlled and made less cytotoxic. Bacteria produce some of the best-characterized functional amyloids, including a surface amyloid fibre called curli. Assembled by enteric bacteria, curli fibres mediate attachment to surfaces and host tissues. Some bacterial amyloids, like harpins and microcinE492, have exploited amyloid toxicity in a directed and functional manner. Here, we review and discuss the functional amyloids assembled by bacteria. Special emphasis will be paid to the biology of functional amyloid synthesis and the connections between bacterial physiology and pathology.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75549/1/j.1462-5822.2008.01148.x.pd

Resource configurations for services success in manufacturing companies

Purpose – The purpose of this paper is to investigate which resources and capabilities are most important to enable large manufacturers undergoing servitization to develop and deliver successful services. Design/methodology/approach – A survey of 155 UK-based manufacturers provided the basis for the study. Data analysis was undertaken using confirmatory factor analysis and multiple regression. Findings – In total, five constructs (“resource configurations”) which enable the development and delivery of successful services and a construct to measure services performance (“Success of Services”) were developed from the literature. A measurement model based on these constructs was empirically tested and verified. Two resource configurations; “Leaders and Services Personnel” and “Services Methods and Tools” were found to make a unique and statistically significant contribution to “Success of Services.” Research limitations/implications – The study highlights the importance of corporates leaders and service employees in developing and delivering success. Service-specific methods and tools are important for developing compelling customer offerings. The study demonstrates the utility of a resource-based perspective in terms of understanding the factors that enable successful services, but also exposes the limitations of using such broad measures, with common lower order resources underpinning multiple resource configurations. The study was conducted from the manufacturer’s perspective, and future studies could also include the customer’s perspective. Practical implications – The research identifies important factors in developing a greater service orientation in manufacturing companies. Originality/value – This is one of the first studies to develop and test a model of services success, generalizable to the population of large manufacturers. </jats:sec

The Spin Content of the Nucleon

The fraction of the nucleon spin that is carried by the quarks, $\Delta \Sigma$, is computed in lattice QCD with dynamical staggered fermions. We obtain the value $\Delta \Sigma = 0.18 \pm 0.02$.Comment: (contribution to Lattice 1992), 4 pages + 1 encapsulated postscript figure, HLRZ 92-81 (In the earlier version the topological charge density was incorrectly normalized. ERRARE HUMANUM EST!

Isolates of Candida albicans that differ in virulence for mice elicit strain-specific antibody-mediated protective responses

Three distinct isolates of Candida albicans were used to establish systemic and oral infections in inbred mice that are genetically resistant or susceptible to tissue damage. Patterns of infection differed significantly between both yeasts and mouse strains. Systemic infection conferred significant protection against re-challenge with the homologous, but not the heterologous yeast; however, the protective effect was more evident in the tissue-susceptible CBA/CaH mice than in the resistant BALB/c strain. In contrast, oral infection induced protection against both homologous and heterologous oral challenge, although this was significant only in the CBA/CaH mice. CBA/CaH mice produced antibodies of both IgG1 and IgG2a subclasses, whereas BALB/c mice produced predominantly IgG1. Western blotting demonstrated considerable differences between epitopes recognised by serum antibodies from mice of both strains after immunisation with each of the three yeasts. Thus, different strains of yeast show considerable specificity in antibody responses elicited by either systemic or oral infection. (c) 2005 Elsevier SAS. All rights reserved