1,422 research outputs found
The Sudden Death of the Nearest Quasar
Galaxy formation is significantly modulated by energy output from
supermassive black holes at the centers of galaxies which grow in highly
efficient luminous quasar phases. The timescale on which black holes transition
into and out of such phases is, however, unknown. We present the first
measurement of the shutdown timescale for an individual quasar using X-ray
observations of the nearby galaxy IC 2497, which hosted a luminous quasar no
more than 70,000 years ago that is still seen as a light echo in `Hanny's
Voorwerp', but whose present-day radiative output is lower by at least 2 and
more likely by over 4 orders of magnitude. This extremely rapid shutdown
provides new insights into the physics of accretion in supermassive black
holes, and may signal a transition of the accretion disk to a radiatively
inefficient state.Comment: 4 pages, 2 figures. Astrophysical Journal Letters, in pres
Association of FCGR2A and FCGR2A-FCGR3A haplotypes with susceptibility to giant cell arteritis
The Fc gamma receptors have been shown to play important roles in the initiation and regulation of many immunological and inflammatory processes and to amplify and refine the immune response to an infection. We have investigated the hypothesis that polymorphism within the FCGR genetic locus is associated with giant cell arteritis (GCA). Biallelic polymorphisms in FCGR2A, FCGR3A, FCGR3B and FCGR2B were examined for association with biopsy-proven GCA (n = 85) and healthy ethnically matched controls (n = 132) in a well-characterised cohort from Lugo, Spain. Haplotype frequencies and linkage disequilibrium (D') were estimated across the FCGR locus and a model-free analysis performed to determine association with GCA. There was a significant association between FCGR2A-131RR homozygosity (odds ratio (OR) 2.10, 95% confidence interval (CI) 1.12 to 3.77, P = 0.02, compared with all others) and carriage of FCGR3A-158F (OR 3.09, 95% CI 1.10 to 8.64, P = 0.03, compared with non-carriers) with susceptibility to GCA. FCGR haplotypes were examined to refine the extent of the association. The haplotype showing the strongest association with GCA susceptibility was the FCGR2A-FCGR3A 131R-158F haplotype (OR 2.84, P = 0.01 for homozygotes compared with all others). There was evidence of a multiplicative joint effect between homozygosity for FCGR2A-131R and HLA-DRB1*04 positivity, consistent with both of these two genetic factors contributing to the risk of disease. The risk of GCA in HLA-DRB1*04 positive individuals homozygous for the FCGR2A-131R allele is increased almost six-fold compared with those with other FCGR2A genotypes who are HLA-DRB1*04 negative. We have demonstrated that FCGR2A may contribute to the 'susceptibility' of GCA in this Spanish population. The increased association observed with a FCGR2A-FCGR3A haplotype suggests the presence of additional genetic polymorphisms in linkage disequilibrium with this haplotype that may contribute to disease susceptibility. These findings may ultimately provide new insights into disease pathogenesis
Loss of BCL9/9l suppresses Wnt driven tumourigenesis in models that recapitulate human cancer.
Different thresholds of Wnt signalling are thought to drive stem cell maintenance, regeneration, differentiation and cancer. However, the principle that oncogenic Wnt signalling could be specifically targeted remains controversial. Here we examine the requirement of BCL9/9l, constituents of the Wnt-enhanceosome, for intestinal transformation following loss of the tumour suppressor APC. Although required for Lgr5+ intestinal stem cells and regeneration, Bcl9/9l deletion has no impact upon normal intestinal homeostasis. Loss of BCL9/9l suppressed many features of acute APC loss and subsequent Wnt pathway deregulation in vivo. This resulted in a level of Wnt pathway activation that favoured tumour initiation in the proximal small intestine (SI) and blocked tumour growth in the colon. Furthermore, Bcl9/9l deletion completely abrogated ÎČ-catenin driven intestinal and hepatocellular transformation. We speculate these results support the just-right hypothesis of Wnt-driven tumour formation. Importantly, loss of BCL9/9l is particularly effective at blocking colonic tumourigenesis and mutations that most resemble those that occur in human cancer
Exile Vol. XXIII No. 2
PROSE
The End of East by Libby Thomas 3-12
Lilt by Andrew Calabrese 13
The Egg Lady by Nancy Jones 14-20
The International Man by Chip Finefrock 21-31
MUSIC
Theme and Variations Op.2, No 1. by J. J. Fuerst 32-38
POETRY
Thrown Out Of The Game by Herberto Padilla to Yannis Ritzos in a Greek jail (Translated from the Spanish by José de Armas) 39
Plumb-Creek In Late Sunlight by Lenore Mayhew 40
untitled by Sharon Singleton 41
untitled by Sharon Singleton 42
A Dance Of Stones by Lawrence Weber 43-44
Carp and Crane by William McNaughton 45
Mountain Ash by Dawn Patnode 46-49
untitled by Mary de Rachewiltz 50
Kai Gar Onar Ek Dios Estin by William McNaughton 51
acute angles by Gay Parks 52
Annihilating All Made To A Thought by Tony Stoneburner 53
Dead Fish by Deneise Deter 54
Changing by Deb Allbery 54
Finish Lines by David A. Goldblatt 55
Malinche\u27s Sister by Tona Dickerson 56
Tarde en el hospital by Carlos Peoza Veliz 57
Afternoon in the Hospital by Carlos Peoza Veliz (Tanslated from the Spanish by Joan Straub) 57
Cuadrados Y Angulos by Alfonaina Storni 58
Squares and Angles by Alfonaina Storni (Translated from the Spanish by Joan Straub) 58
INK DRAWINGS
untitled by Susan Hoagman 2
Self-Portrait or Darla by Julia Weatherford 59
untitled by Katy Booth 70
ESSAYS On As For Poets by Gary Snyder 60-61
Joseph Heller\u27s Something Happened and the Problem of Community in Modern America by Jack Kirby 62-68
EDITOR\u27S NOTE by Lawrence Weber 69-70
CONTRIBUTORS 71-72
The cover ink drawing by Cathy Ries is entitled, Exercise In Exaggerated Contours
Search for CP Violation in the Decay Z -> b (b bar) g
About three million hadronic decays of the Z collected by ALEPH in the years
1991-1994 are used to search for anomalous CP violation beyond the Standard
Model in the decay Z -> b \bar{b} g. The study is performed by analyzing
angular correlations between the two quarks and the gluon in three-jet events
and by measuring the differential two-jet rate. No signal of CP violation is
found. For the combinations of anomalous CP violating couplings, and , limits of \hat{h}_b < 0.59h^{\ast}_{b} < 3.02$ are given at 95\% CL.Comment: 8 pages, 1 postscript figure, uses here.sty, epsfig.st
Health Status of Visitors and Temporary Residents, United States
Education, policy, and interventions to promote visitor health are needed
Idiopathic interstitial pneumonia: Do community and academic physicians agree on diagnosis?
Rationale: Treatment and prognoses of diffuse parenchymal lung
diseases (DPLDs) varies by diagnosis. Obtaining a uniform diagnosis
among observers is difficult.
Objectives: Evaluate diagnostic agreement between academic and
community-based physicians for patients with DPLDs, and determine
if an interactive approach between clinicians, radiologists,
and pathologists improved diagnostic agreement in community
and academic centers.
Methods: Retrospective review of 39 patients with DPLD. A total of
19 participants reviewed cases at 2 community locations and 1
academic location. Information from the history, physical examination,
pulmonary function testing, high-resolution computed tomography,
and surgical lung biopsy was collected. Data were presented
in the same sequential fashion to three groups of physicians on
separate days.
Measurements and Main Results: Each observerâs diagnosis was coded
into one of eight categories. A statistic allowing formultiple raters
was used to assess agreement in diagnosis. Interactions between
clinicians, radiologists, and pathologists improved interobserver
agreement at both community and academic sites; however, final
agreement was better within academic centers (Kappa= 0.55â0.71) than
within community centers (Kappa=0.32â0.44). Clinically significant
disagreement was present between academic and communitybased
physicians (Kappa=0.11â0.56). Community physicians were more
likely to assign a final diagnosis of idiopathic pulmonary fibrosis
compared with academic physicians.
Conclusions: Significant disagreement exists in the diagnosis of
DPLD between physicians based in communities compared with
those in academic centers. Wherever possible, patients should be
referred to centers with expertise in diffuse parenchymal lung disorders
to help clarify the diagnosis and provide suggestions regarding
treatment options.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91941/1/2007 AJRCCM Idiopathic interstitial pneumonia - Do community and academic physicians agree on diagnosis.pd
Release of Nitrogen and Phosphorus from Poultry Litter Amended with Acidified Biochar
Application of poultry litter (PL) to soil may lead to nitrogen (N) losses through ammonia (NH3) volatilization and to potential contamination of surface runoff with PL-derived phosphorus (P). Amending litter with acidified biochar may minimize these problems by decreasing litter pH and by retaining litter-derived P, respectively. This study evaluated the effect of acidified biochars from pine chips (PC) and peanut hulls (PH) on NH3 losses and inorganic N and P released from surface-applied or incorporated PL. Poultry litter with or without acidified biochars was surface-applied or incorporated into the soil and incubated for 21 d. Volatilized NH3 was determined by trapping it in acid. Inorganic N and P were determined by leaching the soil with 0.01 M of CaCl2 during the study and by extracting it with 1 M KCl after incubation. Acidified biochars reduced NH3 losses by 58 to 63% with surface-applied PL, and by 56 to 60% with incorporated PL. Except for PH biochar, which caused a small increase in leached NH4 +-N with incorporated PL, acidified biochars had no effect on leached or KCl-extractable inorganic N and P from surface-applied or incorporated PL. These results suggest that acidified biochars may decrease NH3 losses from PL but may not reduce the potential for P loss in surface runoff from soils receiving PL
Ten Years of Screening and Testing for Acute HIV Infection in North Carolina
To describe demographic and behavioral characteristics of persons with acute HIV infection (AHI) over time
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