1,915 research outputs found
Hadron Spectroscopy with COMPASS at CERN
The aim of the COMPASS hadron programme is to study the light-quark hadron
spectrum, and in particular, to search for evidence of hybrids and glueballs.
COMPASS is a fixed-target experiment at the CERN SPS and features a two-stage
spectrometer with high momentum resolution, large acceptance, particle
identification and calorimetry. A short pilot run in 2004 resulted in the
observation of a spin-exotic state with consistent with the
debated . In addition, Coulomb production at low momentum transfer
data provide a test of Chiral Perturbation Theory. During 2008 and 2009, a
world leading data set was collected with hadron beam which is currently being
analysed. The large statistics allows for a thorough decomposition of the data
into partial waves. The COMPASS hadron data span over a broad range of channels
and shed light on several different aspects of QCD.Comment: 4 pages, 5 figure
Chromogranin A in the pancreatic islet
Chromogranin A (CGA) is the major soluble protein within secretory vesicles of chromaffin cells. A polyclonal antiserum was raised against bovine CGA and characterized in two-dimensional immunoblots. Cellular and subcellular distribution of CGA in bovine pancreatic islet was investigated by immunocytochemistry. At the light microscopic level, CGA-like immunoreactivity was found in the same cells that react with antibodies against insulin, glucagon, and somatostatin. A minority of cells containing pancreatic polypeptide also showed faint immunostaining. At the ultrastructural level (protein A-gold technique), CGA-like immunoreactivity was confined exclusively to the secretory vesicles. Whereas the hormones were localized mainly in the central part of the secretory vesicles, CGA was present predominantly in the periphery. These findings indicate that a CGA-like protein is a regular constituent of the matrix of secretory vesicles in pancreatic endocrine cells
Geographic Variation of Cirques on Iceland: Factors Influencing Cirque Morphology
Cirques are one of the most common glacial landforms in alpine settings. They also provide important paleoclimate information (e.g. Meierding 1984; Evans 2006). The purpose of this study is to fill in gaps in the climate record of Iceland by conducting a quantitative analysis of cirques in three regions in Iceland: Tröllaskagi, the East Fjords, and VestfirĂ°ir. Iceland, located in the center of the North Atlantic Ocean, contains many small glaciers, in addition to large ice caps. The glaciers on Iceland are particularly sensitive to variations in oceanic and atmospheric circulation (Andresen et al. 2005; GeirsdĂłttir et al., 2009; ĂlafsdĂłttir et al. 2010). Iceland thus provides an excellent case study to examine factors influencing glacial landforms such as cirques. (excerpt
Fermi Surface of KFeAs from Quantum Oscillations in Magnetostriction
We present a study of the Fermi surface of KFeAs single crystals.
Quantum oscillations were observed in magnetostriction measured down to 50 mK
and in magnetic fields up to 14 T. For , the calculated
effective masses are in agreement with recent de Haas-van Alphen and ARPES
experiments, showing enhanced values with respect to the ones obtained from
previous band calculations. For , we observed a small orbit at a
cyclotron frequency of 64 T, characterized by an effective mass of , supporting the presence of a three-dimensional pocket at the Z-point.Comment: SCES Conference, Tokyo 201
Conservation Tillage, Pesticide Use, and Biotech Crops in the U.S.A.
This paper presents the first part of an ongoing project whose objective is to present a long term relationship between conservation tillage, adoption of GE crops and pesticide use for major crops in the United States. In addition, the project aims to provide some innovative tests on causality using a panel data set. This paper presents preliminary results for soybeans.conservation tillage, biotechnology, genetically engineered crops, soybeans, herbicides, Environmental Economics and Policy, Farm Management, Production Economics,
Baseball Card Pricing Model: A Demonstration with Well-known Players
A simple hedonic pricing model is developed for baseball cards, of the type often used successfully to model prices for artworks. The model is estimated for a dataset of twelve well-known players observed at eight points in time over a span of twenty years. Dummy variables are used to capture various relevant characteristics of the player or card. This model was estimated separately for two different approaches or assumptions about rates of return. Estimates perform extremely well, explaining most differences among baseball card prices for the cards in the sample. Among extrinsic variables that represent specific players and card characteristics that differentiate cards issued during the same season, race had a significant positive effect on price for black players. Batting average and number of World Series appearances had significant positive impacts on price, but surprisingly, rookie cards tended to be worth relatively less than non-rookie cards. Similarly unexpected findings with respect to players\u27 death and elevation to the Hall of Fame may result from trying to estimate too many characteristics simultaneously on a limited dataset. Results suggest famous players\u27 cards generally are extremely attractive investment instruments
Impact of GE Crop Adoption on Quality-Adjusted Herbicide Use in U.S. Corn Production
This paper presents findings on the use of HT corn and quality-adjusted herbicide use for 12 key corn producing states using a panel data set for 1986-2008. Our preliminary findings indicate an insignificant impact of HT corn on herbicide use, conditioning or accounting for HT corn with other important drivers of corn herbicide use: HT soy, corn output price, glyphoste price, nonherbicide glyponsate price, and percentage of continuous corn and low-till corn. However, we find a positive and significant impact of HT corn on herbicide use in selected states, using regional interaction terms. We use econometric techniques to avoid spurious regression results. Other preliminary runs indicated that the results hold when running the US and regional interactions on 1986-2006 and 1986-2007 data.HT-corn, herbicides, weed resistance, glyphosate, corn, Environmental Economics and Policy, Farm Management, Production Economics,
Magnetic and structural quantum phase transitions in CeCu6-xAux are independent
The heavy-fermion compound CeCuAu has become a model system for
unconventional magnetic quantum criticality. For small Au concentrations , the compound undergoes a structural transition from
orthorhombic to monoclinic crystal symmetry at a temperature with
for . Antiferromagnetic order sets in
close to . To shed light on the interplay between quantum
critical magnetic and structural fluctuations we performed neutron-scattering
and thermodynamic measurements on samples with . The
resulting phase diagram shows that the antiferromagnetic and monoclinic phase
coexist in a tiny Au concentration range between and . The
application of hydrostatic and chemical pressure allows to clearly separate the
transitions from each other and to explore a possible effect of the structural
transition on the magnetic quantum critical behavior. Our measurements
demonstrate that at low temperatures the unconventional quantum criticality
exclusively arises from magnetic fluctuations and is not affected by the
monoclinic distortion.Comment: 5 pages, 3 figure
Acute Cytomegalovirus Colitis Presenting during Primary HIV Infection: an Unusual Case of an Immune Reconstitution Inflammatory Syndrom
Severe ulcerous cytomegalovirus pancolitis developed during primary human immunodeficiency virus (HIV) infection in a patient who underwent early combination antiretroviral treatment. This massive inflammatory process led to acute colon perforation. Serological testing demonstrated cytomegalovirus reactivation. Severe immunosuppression caused by primary HIV infection resulted in cytomegalovirus colitis, and initiation of early combination antiretroviral therapy triggered an immune reconstitution inflammatory syndrome potentially leading to colonic perforatio
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