Towards a National Housing Strategy for Homeless Youth

This policy brief, "Towards a National Housing Strategy for Homeless Youth", is part of a series developed by the Hollywood Homeless Youth Partnership (HHYP) to advance policy and practice recommendations focused on preventing and ending youth homelessness. This brief emerges from "No Way Home: Understanding the Needs and Experiences of Homeless Youth in Hollywood", a report released by the HHYP in November 2010 presenting findings from a multi-method needs assessment conducted with 389 homeless youth ages 12 to 25 in the Hollywood community.The purpose of this brief is to address the inadequacies of prioritizing permanent housing as the only solution for homeless youth, identify the major limitations of our existing housing programs, and advocate for developing a national housing strategy and funding a full housing continuum for homeless young people that is responsive to their unique needs and circumstances. This brief is being released at a time of unprecedented interest in the issue of youth homelessness -- we hope it will inform federal and local planning and decision-making and help advance our national agenda of preventing and ending youth homelessness

Geochemistry of As-, F- and B-bearing waters in and around San Antonio de los Cobres, Argentina, and implications for drinking and irrigation water quality

Spring, stream and tap waters from in and around San Antonio de los Cobres, Salta, Argentina, were sampled to characterize their geochemical signatures, and to determine whether they pose a threat to human health and crops. The spring waters are typical of geothermal areas world-wide, in that they are Na-Cl waters with high concentrations of Astot, As(III), Li, B, HCO3, F and SiO2 (up to 9.49, 8.92, 13.1, 56.6, 1250, 7.30 and 57.2 mg L-1, respectively), and result from mixing of deep Na-Cl brines and meteoric HCO3-rich waters. Springs close to the town of San Antonio have higher concentrations of all elements, and are generally cooler, than springs in the Baños de Agua Caliente. Spring water chemistry is a result of mixing of deep Na-Cl brines and meteoric HCO3 waters. Stream waters are also Na-Cl type, and receive large inputs of all elements from the springs near San Antonio, but concentrations decrease downstream through the town of San Antonio due to mineral precipitation. The spring that is used as a drinking water source, and other springs in the area, have As, F and B concentrations in excess of WHO and Argentinian drinking water guidelines. Evaluation of the waters for irrigation purposes suggests that their high salinities and B concentrations may adversely affect crops. The waters may be improved for drinking and irrigation by dilution with cleaner meteoric waters, mineral precipitation or by use of commercial filters. Such recommendations could also be followed by other settlements that draw drinking and irrigation waters from geothermal sources

Developing an e-infrastructure for social science

We outline the aims and progress to date of the National Centre for e-Social Science e-Infrastructure project. We examine the challenges faced by the project, namely in ensuring outputs are appropriate to social scientists, managing the transition from research projects to service and embedding software and data within a wider infrastructural framework. We also provide pointers to related work where issues which have ramifications for this and similar initiatives are being addressed

Evolution of leaf-form in land plants linked to atmospheric CO2 decline in the Late Palaeozoic era

The widespread appearance of megaphyll leaves, with their branched veins and planate form, did not occur until the close of the Devonian period at about 360 Myr ago. This happened about 40 Myr after simple leafless vascular plants first colonized the land in the Late Silurian/Early Devonian, but the reason for the slow emergence of this common feature of present-day plants is presently unresolved. Here we show, in a series of quantitative analyses using fossil leaf characters and biophysical principles, that the delay was causally linked with a 90% drop in atmospheric pCO2 during the Late Palaeozoic era. In contrast to simulations for a typical Early Devonian land plant, possessing few stomata on leafless stems, those for a planate leaf with the same stomatal characteristics indicate that it would have suffered lethal overheating, because of greater interception of solar energy and low transpiration. When planate leaves first appeared in the Late Devonian and subsequently diversified in the Carboniferous period, they possessed substantially higher stomatal densities. This observation is consistent with the effects of the pCO2 on stomatal development and suggests that the evolution of planate leaves could only have occurred after an increase in stomatal density, allowing higher transpiration rates that were sufficient to maintain cool and viable leaf temperatures

On non-abelian T-dual geometries with Ramond fluxes

We show how to implement T-duality along non-abelian isometries in backgrounds with non-vanishing Ramond fields. When the dimension of the isometry group is odd (even) the duality swaps (preserves) the chirality of the theory. In certain cases a non-abelian duality can result in a massive type-IIA background. We provide two examples by dualising SU(2) isometry subgroups in $AdS_5\times S^5$ and $AdS_3\times S^3\times T^4$. The resultant dual geometries inherit the original AdS factors but have transverse spaces with reduced isometry and preserve only half of the original supersymmetry. The non-abelian dual of $AdS_5\times S^5$ has an M-theory lift which is related to the gravity duals of N=2 superconformal theories. We comment on a possible interpretation of this as a high spin limit.Comment: 33 page

Eigenvector-based identification of bipartite subgraphs

We report our experiments in identifying large bipartite subgraphs of simple connected graphs which are based on the sign pattern of eigenvectors belonging to the extremal eigenvalues of different graph matrices: adjacency, signless Laplacian, Laplacian, and normalized Laplacian matrix. We compare the performance of these methods to a local switching algorithm based on the Erdos bound that each graph contains a bipartite subgraph with at least half of its edges. Experiments with one scale-free and three random graph models, which cover a wide range of real-world networks, show that the methods based on the eigenvectors of the normalized Laplacian and the adjacency matrix yield slightly better, but comparable results to the local switching algorithm. We also formulate two edge bipartivity indices based on the former eigenvectors, and observe that the method of iterative removal of edges with maximum bipartivity index until one obtains a bipartite subgraph, yields comparable results to the local switching algorithm, and significantly better results than an analogous method that employs the edge bipartivity index of Estrada and Gomez-Gardenes.Comment: 20 pages, 8 figure

Telomere lengths in human oocytes, cleavage stage embryos and blastocysts

Telomeres are repeated sequences that protect the ends of chromosomes and harbour DNA-repair proteins. Telomeres shorten during each cell division in the absence of telomerase. When telomere length becomes critically short, cell senescence occurs. Telomere length therefore reflects both cellular ageing and capacity for division. We have measured telomere length in human germinal vesicle (GV) oocytes and pre-implantation embryos, by quantitative fluorescence in-situ hybridisation (Q-FISH), providing baseline data towards our hypothesis that telomere length is a marker of embryo quality. The numbers of fluorescent foci suggest that extensive clustering of telomeres occurs in mature GV stage oocytes, and in pre-implantation embryos. When calculating average telomere length by assuming that each signal presents one telomere, the calculated telomere length decreased from the oocyte to the cleavage stages, and increased between the cleavage stages and the blastocyst (11.12 vs 8.43 vs 12.22kb respectively, p<0.001). Other methods of calculation, based upon expected maximum and minimum numbers of telomeres, confirm that telomere length in blastocysts is significantly longer than cleavage stages. Individual blastomeres within an embryo showed substantial variation in calculated average telomere length. This study implies that telomere length changes according to the stage of pre-implantation embryo development

Modelling glacial lake outburst flood impacts in the Bolivian Andes

The Bolivian Andes have experienced sustained and widespread glacier mass loss in recent decades. Glacier recession has been accompanied by the development of proglacial lakes, which pose a glacial lake outburst flood (GLOF) risk to downstream communities and infrastructure. Previous research has identified three potentially dangerous glacial lakes in the Bolivian Andes, but no attempt has yet been made to model GLOF inundation downstream from these lakes. We generated 2-m resolution DEMs from stereo and tri-stereo SPOT 6/7 satellite images to drive a hydrodynamic model of GLOF flow (HEC-RAS 5.0.3). The model was tested against field observations of a 2009 GLOF from Keara, in the Cordillera Apolobamba, and was shown to reproduce realistic flood depths and inundation. The model was then used to model GLOFs from Pelechuco lake (Cordillera Apolobamba) and Laguna Arkhata and Laguna Glaciar (Cordillera Real). In total, six villages could be affected by GLOFs if all three lakes burst. For sensitivity analysis, we ran the model for three scenarios (pessimistic, intermediate, optimistic), which give a range of ~ 1100 to ~ 2200 people affected by flooding; between ~ 800 and ~ 2100 people could be exposed to floods with a flow depth ≥ 2 m, which could be life threatening and cause a significant damage to infrastructure. We suggest that Laguna Arkhata and Pelechuco lake represent the greatest risk due to the higher numbers of people who live in the potential flow paths, and hence, these two glacial lakes should be a priority for risk managers

Nuclear receptors in vascular biology

Nuclear receptors sense a wide range of steroids and hormones (estrogens, progesterone, androgens, glucocorticoid, and mineralocorticoid), vitamins (A and D), lipid metabolites, carbohydrates, and xenobiotics. In response to these diverse but critically important mediators, nuclear receptors regulate the homeostatic control of lipids, carbohydrate, cholesterol, and xenobiotic drug metabolism, inflammation, cell differentiation and development, including vascular development. The nuclear receptor family is one of the most important groups of signaling molecules in the body and as such represent some of the most important established and emerging clinical and therapeutic targets. This review will highlight some of the recent trends in nuclear receptor biology related to vascular biology

Androgen receptor phosphorylation at serine 515 by Cdk1 predicts biochemical relapse in prostate cancer patients

&lt;br&gt;Background:Prostate cancer cell growth is dependent upon androgen receptor (AR) activation, which is regulated by specific kinases. The aim of the current study is to establish if AR phosphorylation by Cdk1 or ERK1/2 is of prognostic significance.&lt;/br&gt; &lt;br&gt;Methods: Scansite 2.0 was utilised to predict which AR sites are phosphorylated by Cdk1 and ERK1/2. Immunohistochemistry for these sites was then performed on 90 hormone-naive prostate cancer specimens. The interaction between Cdk1/ERK1/2 and AR phosphorylation was investigated in vitro using LNCaP cells.&lt;/br&gt;&lt;br&gt;Results:Phosphorylation of AR at serine 515 (pAR(S515)) and PSA at diagnosis were independently associated with decreased time to biochemical relapse. Cdk1 and pCdk1(161), but not ERK1/2, correlated with pAR(S515). High expression of pAR(S515) in patients with a PSA at diagnosis of &#8804;20 ng ml(-1) was associated with shorter time to biochemical relapse (P=0.019). This translated into a reduction in disease-specific survival (10-year survival, 38.1% vs 100%, P&#60;0.001). In vitro studies demonstrated that treatment with Roscovitine (a Cdk inhibitor) caused a reduction in pCdk1(161) expression, pAR(S515)expression and cellular proliferation.&lt;/br&gt; &lt;br&gt;Conclusion: In prostate cancer patients with PSA at diagnosis of &#8804;20 ng ml(-1), phosphorylation of AR at serine 515 by Cdk1 may be an independent prognostic marker.&lt;/br&gt