Heterotic Black Horizons

We show that the supersymmetric near horizon geometry of heterotic black holes is either an AdS_3 fibration over a 7-dimensional manifold which admits a G_2 structure compatible with a connection with skew-symmetric torsion, or it is a product R^{1,1} * S^8, where S^8 is a holonomy Spin(7) manifold, preserving 2 and 1 supersymmetries respectively. Moreover, we demonstrate that the AdS_3 class of heterotic horizons can preserve 4, 6 and 8 supersymmetries provided that the geometry of the base space is further restricted. Similarly R^{1,1} * S^8 horizons with extended supersymmetry are products of R^{1,1} with special holonomy manifolds. We have also found that the heterotic horizons with 8 supersymmetries are locally isometric to AdS_3 * S^3 * T^4, AdS_3 * S^3 * K_3 or R^{1,1} * T^4 * K_3, where the radii of AdS_3 and S^3 are equal and the dilaton is constant.Comment: 35 pages, latex. Minor alterations to equation (3.11) and section 4.1, the conclusions are not affecte

ST2249-MRSA-III: a second major recombinant methicillin-resistant Staphylococcus aureus clone causing healthcare infection in the 1970s

Typing of healthcare-associated MRSA from Australia in the 1970s revealed a novel clone, ST2249-MRSA-III (CC45), present from 1973 to 1979. This clone was present prior to the Australian epidemic caused by the recombinant clone, ST239-MRSA-III. This study aimed to characterise the genome of ST2249-MRSA-III in order to establish its relationship to other MRSA clones. DNA microarray analysis was conducted and a draft genome sequence of ST2249 was obtained. The recombinant structure of the ST2249 genome was revealed by comparisons to publicly available ST239 and ST45 genomes. Microarray analysis of genomic DNA of 13 ST2249 isolates showed gross similarities with the ST239 chromosome in a segment around the origin of replication and with ST45 for the remainder of the chromosome. Recombination breakpoints were precisely determined by the changing pattern of nucleotide polymorphisms in the genome sequence of ST 2249 isolate SK1585 compared with ST239 and ST45. One breakpoint was identified to the right of oriC, between sites 1014 and 1065 of the gene D484_00045. Another was identified to the left of oriC, between sites 1185 and 1248 of D484_01632. These results indicate that ST2249 inherited approximately 35.3% of its chromosome from an ST239- like parent and 64.7% from an ST45-like parent. ST2249-MRSA-III resulted from a major recombination between parents that resemble ST239 and ST45. Although only limited Australian archival material is available, the oldest extant isolate of ST2249 predates the oldest Australian isolate of ST239 by three years. It is therefore plausible that these two recombinant clones were introduced into Australia separately

Determining utility values related to malaria and malaria chemoprophylaxis

<p>Abstract</p> <p>Background</p> <p>Chemoprophylaxis for travellers' malaria is problematic. Decision modeling may help determine optimal prevention strategies for travellers' malaria. Such models can fully assess effect of drug use and disease on quality of life, and help travellers make informed values based decisions. Such models require utility values reflecting societal preferences over different health states of relevance. To date, there are no published utility values relating to clinical malaria or chemoprophylaxis adverse events.</p> <p>Methods</p> <p>Utility estimates for health states related to falciparum malaria, sequelae and drug-related adverse events were obtained using a self-administered visual analogue scale in 20 individuals. Utility values for health states related to clinical malaria were obtained from a survey of 11 malaria experts questioned about length of hospital stay or equivalent disability with simple and severe travellers' malaria.</p> <p>Results</p> <p>The general public (potential travellers), were more tolerant of taking prophylaxis if associated with no or mild AEs and least tolerant of mild sequelae from malaria and severe drug related events. The rating value reported for taking no prophylaxis was quite variable. Tropical medicine specialists estimated a mean hospital stay 3.23 days (range 0.5-4.5 days) for simple and 6.36 days (range 4.5 - 7 days) for severe malaria.</p> <p>Conclusions</p> <p>This study provides a benchmark for important utility value estimates for modeling malaria and drug-related outcomes in non-immune travellers.</p

Identification of signaling pathways in early mammary gland development by mouse genetics

The mammary gland develops as an appendage of the ectoderm. The prenatal stage of mammary development is hormone independent and is regulated by sequential and reciprocal signaling between the epithelium and the mesenchyme. A number of recent studies using human and mouse genetics, in particular targeted gene deletion and transgenic expression, have identified some of the signals that control specific steps in development. This process involves cell specification and proliferation, reciprocal tissue interactions and cell migration. Since some of these events are recapitulated during tumorigenesis, an understanding of these signaling pathways may contribute to the development of targeted therapies and novel drugs

Increased EMRSA-15 health-care worker colonization demonstrated in retrospective review of EMRSA hospital outbreaks

Background:Health care worker (HCW) colonization with methicillin resistant Staphylococcus aureus (MRSA) is a documented cause of hospital outbreaks and contributes to ongoing transmission. At Royal Perth Hospital (RPH) it had been anecdotally noted that the increasing prevalence of EMRSA-15 appeared to be associated with increased HCW colonization compared with Aus2/3-EMRSA. Hence we compared HCW colonization rates during outbreaks of EMRSA-15 and Aus2/3-EMRSA at a single institution.Methods:We performed a retrospective review of EMRSA-15 and Aus2/3-EMRSA outbreaks from 2000 –2009 at RPH, a quaternary hospital in Western Australia. Outbreak files were reviewed and relevant data extracted. Results:Ten EMRSA-15 outbreaks were compared with seven Aus2/3 outbreaks. The number of patients colonized was similar between EMRSA-15 and Aus2/ 3-EMRSA outbreaks (median 7 [range 3 – 20] and 11 [5 – 26], respectively; P = 0.07) but the number of HCWs colonized was significantl y higher in EMRSA-15 outbreaks compared to Aus2/3-EMRSA outbreaks (median 4 [range 0 – 15] and 2 [1-3], respectively; P = 0.013). The percentage of HCWs colonized was also higher in EMRSA-15 outbreaks versus Aus2/3-EMRSA outbreaks (median 3.4% [range 0 – 5.5%] and 0.81% [0.56 – 2.2%], respectively; P= 0.013).Conclusions:This study demonstrates a higher level of HCW colonization during EMRSA-15 outbreaks compared with Aus2/3-EMRSA outbreaks. This finding suggests that MRSA vary in their ability to colonize HCWs and contribute to outbreaks. MRSA type should be determined during outbreaks and future research should investigate the mechanisms by which EMRSA-15 contributes to increased HCW colonization

Australian Enterococcal Sepsis Outcome Programme, 2011

From 1 January to 31 December 2011, 29 institutions around Australia participated in the Australian Enterococcal Sepsis Outcome Programme (AESOP). The aim of AESOP 2011 was to determine the proportion of enterococcal bacteraemia isolates in Australia that are antimicrobial resistant, with particular emphasis on susceptibility to ampicillin and the glycopeptides, and to characterise the molecular epidemiology of the Enterococcus faecalis and E. faecium isolates. Of the 1,079 unique episodes of bacteraemia investigated, 95.8% were caused by either E. faecalis (61.0%) or E. faecium (34.8%). Ampicillin resistance was detected in 90.4% of E. faecium but not detected in E. faecalis. Using Clinical and Laboratory Standards Institute breakpoints (CLSI), vancomycin non-susceptibility was reported in 0.6% and 31.4% of E. faecalis and E. faecium respectively and was predominately due to the acquisition of the vanB operon. Approximately 1 in 6 vanB E. faecium isolates however, had an minimum inhibitory concentration at or below the CLSI vancomycin susceptible breakpoint of &le; 4 mg/L. Overall, 37% of E. faecium harboured vanA or vanB genes. Although molecular typing identified 126 E. faecalis pulsed-field gel electrophoresis (PFGE) pulsotypes, more than 50% belonged to 2 pulsotypes that were isolated across Australia. E. faecium consisted of 73 PFGE pulsotypes from which 43 multilocus sequence types were identified. Almost 90% of the E. faecium were identified as clonal complex 17 clones, of which approximately half were characterised as sequence type 203, which was isolated Australia-wide. In conclusion, the AESOP 2011 has shown that although polyclonal, enterococcal bacteraemias in Australia are frequently caused by ampicillin-resistant vanB E. faecium

The structure of F₁-ATPase from Saccharomyces cerevisiae inhibited by its regulatory protein IF₁.

The structure of F₁-ATPase from Saccharomyces cerevisiae inhibited by the yeast IF₁ has been determined at 2.5 Å resolution. The inhibitory region of IF₁ from residues 1 to 36 is entrapped between the C-terminal domains of the α(DP)- and β(DP)-subunits in one of the three catalytic interfaces of the enzyme. Although the structure of the inhibited complex is similar to that of the bovine-inhibited complex, there are significant differences between the structures of the inhibitors and their detailed interactions with F₁-ATPase. However, the most significant difference is in the nucleotide occupancy of the catalytic β(E)-subunits. The nucleotide binding site in β(E)-subunit in the yeast complex contains an ADP molecule without an accompanying magnesium ion, whereas it is unoccupied in the bovine complex. Thus, the structure provides further evidence of sequential product release, with the phosphate and the magnesium ion released before the ADP molecule.Support for this work was provided by the Medical Research Council, UK, including a PhD studentship (to G.C.R.) and a Career Training Fellowship (to J.V.B.), by the European Drug Initiative in Channels and Transporters (EDICT; to J.E.W.), and by a grant from NIH no. R01GM66223 to D.M.M

Liquid Polymorphism and Double Criticality in a Lattice Gas Model

We analyze the possible phase diagrams of a simple model for an associating liquid proposed previously. Our two-dimensional lattice model combines oreintati onal ice-like interactions and \"{}Van der Waals\"{} interactions which may be repulsive, and in this case represent a penalty for distortion of hydrogen bonds in the presence of extra molecules. These interactions can be interpreted in terms of two competing distances, but not necessarily soft-core. We present mean -field calculations and an exhaustive simulation study for different parameters which represent relative strength of the bonding interaction to the energy penalty for its distortion. As this ratio decreases, a smooth disappearance of the doubl e criticality occurs. Possible connections to liquid-liquid transitions of molecul ar liquids are suggested

Topology of supersymmetric N=1, D=4 supergravity horizons

All supersymmetric N=1, D=4 supergravity horizons have toroidal or spherical topology, irrespective of whether the black hole preserves any supersymmetry.Comment: 17 pages, latex. Alterations to introduction and section 3.

On Symmetries of Extremal Black Holes with One and Two Centers

After a brief introduction to the Attractor Mechanism, we review the appearance of groups of type E7 as generalized electric-magnetic duality symmetries in locally supersymmetric theories of gravity, with particular emphasis on the symplectic structure of fluxes in the background of extremal black hole solutions, with one or two centers. In the latter case, the role of an "horizontal" symmetry SL(2,R) is elucidated by presenting a set of two-centered relations governing the structure of two-centered invariant polynomials.Comment: 1+13 pages, 2 Tables. Based on Lectures given by SF and AM at the School "Black Objects in Supergravity" (BOSS 2011), INFN - LNF, Rome, Italy, May 9-13 201