28 research outputs found

    Closed String Tachyons and Semi-Classical Instabilities

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    We conjecture that the end point of bulk closed string tachyon decay at any non-zero coupling, is the annihilation of space time by Witten's bubble of nothing, resulting in a topological phase of the theory. In support of this we present a variety of situations in which there is a correspondence between the existence of perturbative tachyons in one regime and the semi-classical annihilation of space-time. Our discussion will include many recently investigated scenarios in string theory including Scherk-Schwarz compactifications, Melvin magnetic backgrounds, and noncompact orbifolds. We use this conjecture to investigate a possible web of dualities relating the eleven-dimensional Fabinger-Horava background with nonsupersymmetric string theories. Along the way we point out where our conjecture resolves some of the puzzles associated with bulk closed string tachyon condensation.Comment: 31 pages, 5 figures 3 figures added, typos corrected and references added. Discussion of Type 0/Heterotic s-duality extended and some other points clarified Revision of discussion on Fabinger-Horava string descendents, section on Scherk-Schwarz compactification of Horava-Witten removed, some references adde

    Meta-analysis of type 2 Diabetes in African Americans Consortium

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    Type 2 diabetes (T2D) is more prevalent in African Americans than in Europeans. However, little is known about the genetic risk in African Americans despite the recent identification of more than 70 T2D loci primarily by genome-wide association studies (GWAS) in individuals of European ancestry. In order to investigate the genetic architecture of T2D in African Americans, the MEta-analysis of type 2 DIabetes in African Americans (MEDIA) Consortium examined 17 GWAS on T2D comprising 8,284 cases and 15,543 controls in African Americans in stage 1 analysis. Single nucleotide polymorphisms (SNPs) association analysis was conducted in each study under the additive model after adjustment for age, sex, study site, and principal components. Meta-analysis of approximately 2.6 million genotyped and imputed SNPs in all studies was conducted using an inverse variance-weighted fixed effect model. Replications were performed to follow up 21 loci in up to 6,061 cases and 5,483 controls in African Americans, and 8,130 cases and 38,987 controls of European ancestry. We identified three known loci (TCF7L2, HMGA2 and KCNQ1) and two novel loci (HLA-B and INS-IGF2) at genome-wide significance (4.15 × 10(-94)<P<5 × 10(-8), odds ratio (OR)  = 1.09 to 1.36). Fine-mapping revealed that 88 of 158 previously identified T2D or glucose homeostasis loci demonstrated nominal to highly significant association (2.2 × 10(-23) < locus-wide P<0.05). These novel and previously identified loci yielded a sibling relative risk of 1.19, explaining 17.5% of the phenotypic variance of T2D on the liability scale in African Americans. Overall, this study identified two novel susceptibility loci for T2D in African Americans. A substantial number of previously reported loci are transferable to African Americans after accounting for linkage disequilibrium, enabling fine mapping of causal variants in trans-ethnic meta-analysis studies.Peer reviewe

    Novel Loci for Adiponectin Levels and Their Influence on Type 2 Diabetes and Metabolic Traits : A Multi-Ethnic Meta-Analysis of 45,891 Individuals

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    J. Kaprio, S. Ripatti ja M.-L. Lokki työryhmien jäseniä.Peer reviewe

    THE RATE OF BINARY BLACK HOLE MERGERS INFERRED FROM ADVANCED LIGO OBSERVATIONS SURROUNDING GW150914

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    A transient gravitational-wave signal, GW150914, was identi fi ed in the twin Advanced LIGO detectors on 2015 September 2015 at 09:50:45 UTC. To asse ss the implications of this discovery, the detectors remained in operation with unchanged con fi gurations over a period of 39 days around the time of t he signal. At the detection statistic threshold corresponding to that observed for GW150914, our search of the 16 days of simultaneous two-detector observational data is estimated to have a false-alarm rate ( FAR ) of < ́ -- 4.9 10 yr 61 , yielding a p -value for GW150914 of < ́ - 210 7 . Parameter estimation follo w-up on this trigger identi fi es its source as a binary black hole ( BBH ) merger with component masses ( )( ) = - + - + mm M ,36,29 12 4 5 4 4 at redshift = - + z 0.09 0.04 0.03 ( median and 90% credible range ) . Here, we report on the constraints these observations place on the rate of BBH coalescences. Considering only GW150914, assuming that all BBHs in the universe have the same masses and spins as this event, imposing a search FAR threshold of 1 per 100 years, and assuming that the BBH merger rate is constant in the comoving frame, we infer a 90% credible range of merger rates between – -- 2 53 Gpc yr 31 ( comoving frame ) . Incorporating all search triggers that pass a much lower threshold while accounting for the uncerta inty in the astrophysical origin of each trigger, we estimate a higher rate, ranging from – -- 13 600 Gpc yr 31 depending on assumptions about the BBH mass distribution. All together, our various rate estimat es fall in the conservative range – -- 2 600 Gpc yr 31

    Influência do grão de sorgo como fonte de amido em ovinos alimentados com feno: parâmetros plasmáticos Influence of sorghum grain as a source of starch in sheep fed hay: plasma parameters

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    O objetivo deste trabalho experimental foi verificar a influência de diferentes níveis de grão de sorgo, como fonte de amido, nos parâmetros plasmáticos em ovinos alimentados com feno de capim-elefante (Pennisetum purpureum Schum). O sorgo foi utilizado em quatro níveis na dieta: 0, 15, 30 e 45%. Foram usados 12 ovinos machos castrados distribuídos em quatro tratamentos com três repetições. Foram coletadas seis amostras de sangue por animal logo antes da refeição da manhã (hora zero) e 1, 2, 3, 4, 6 e 8 horas após. O delineamento experimental foi o completamente casualizado. A 1ª hora após a refeição apresentou a maior concentração plasmática de uréia (53,3 mg/100 mL) e foi superior à 6ª e 8ª hora (49,5 e 49,3 mg/100 mL). A maior concentração de uréia no plasma coincidiu com a maior concentração de amônia no líquido ruminal. O tratamento com 30% de sorgo na dieta apresentou concentração plasmática de glicose de 81,0 mg/100 mL e foi superior ao tratamento testemunha (60,4 mg/100 mL). A concentração de insulina variou entre tratamentos para cada hora de coleta após a refeição, de acordo com os níveis de sorgo na dieta. O tratamento com 45% de sorgo apresentou a maior concentração do hormônio no plasma. Observou-se para todos os tratamentos um pico de produção do hormônio na 4ª hora após a refeição.<br>The objective of this experimental work was to evaluate the influence of different levels of sorghum grain, as a source of starch, on the plasma parameters of sheep fed elephant grass hay (Pennisetum purpureum Schum). Sorghum grain was included in the diet at four levels: 0, 15, 30 e 45%. Twelve castrated male sheep were assigned to four treatments with three replicates. Six samples of blood per animal were collected just before the morning feeding (zero hour) and after 1, 2, 3, 4, 6 and 8 hours. A completely randomized design was used. The first hour after feeding showed the highest plasma concentration of urea (53.3 mg/100 mL) and was higher than the six and eight-hour samples (49.5 and 49.3 mg/100 mL). The higher concentration of urea in the plasma coincided with the highest concentration of ammonia in the ruminal liquor. Treatment including 30% sorghum in the diet showed a glucose plasmatic concentration of 81,0 mg/100 mL and was superior to the control treatment (60.4 mg/100 mL). Insulin concentration varied among treatments for each hour of collection after feeding according to the levels of sorghum in the diet. The treatment that included 45% sorghum grain showed the highest concentration of this hormone in the plasma. It was observed a peak of the insulin production at the four-hour after feeding
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