7,358 research outputs found
Spin Correlations of Lambda anti-Lambda Pairs as a Probe of Quark-Antiquark Pair Production
The polarizations of Lambda and anti-Lambda are thought to retain memories of
the spins of their parent s quarks and antiquarks, and are readily measurable
via the angular distributions of their daughter protons and antiprotons.
Correlations between the spins of Lambda and anti-Lambda produced at low
relative momenta may therefore be used to probe the spin states of s anti-s
pairs produced during hadronization. We consider the possibilities that they
are produced in a 3P_0 state, as might result from fluctuations in the
magnitude of , a 1S_0 state, as might result from chiral
fluctuations, or a 3S_1 or other spin state, as might result from production by
a quark-antiquark or gluon pair. We provide templates for the p anti-p angular
correlations that would be expected in each of these cases, and discuss how
they might be used to distinguish s anti-s production mechanisms in pp and
heavy-ion collisions.Comment: 12 pages, 3 figure
A Spitzer View of the Young Open Cluster NGC 2264
We have performed mid-IR photometry of the young open cluster NGC 2264 using
the images obtained with the Spitzer Space Telescope IRAC and MIPS instruments
and present a normalized classification scheme of young stellar objects in
various color-color diagrams to make full use of the information from
multicolor photometry. These results are compared with the classification
scheme based on the slope of the spectral energy distribution (SED).
From the spatial distributions of Class I and II stars, we have identified
two subclusterings of Class I objects in the CONE region of Sung et al. The
disked stars in the other star forming region S MON are mostly Class II
objects. These three regions show a distinct difference in the fractional
distribution of SED slopes as well as the mean value of SED slopes. The
fraction of stars with primordial disks is nearly flat between log m = 0.2 --
-0.5, and that of transition disks is very high for solar mass stars. In
addition, we have derived a somewhat higher value of the primordial disk
fraction for NGC 2264 members located below the main pre-main sequence locus
(so-called BMS stars). This result supports the idea that BMS stars are young
stars with nearly edge-on disks. We have also found that the fraction of
primordial disks is very low near the most massive star S Mon and increases
with distance from S Mon.Comment: 38 pages, 21 figures, 5 tables (AJ accepted
Disentangling Higgs-Top Couplings in Associated Production
In the presence of CP violation, the Higgs-top coupling may have both scalar
and pseudoscalar components, and , which are
bounded indirectly but only weakly by the present experimental constraints on
the Higgs-gluon-gluon and Higgs-- couplings, whereas upper
limits on electric dipole moments provide strong additional indirect
constraints on , if the Higgs-electron coupling is similar
to that in the Standard Model and there are no cancellations with other
contributions. We discuss methods to measure directly the scalar and
pseudoscalar Higgs-top couplings by measurements of Higgs production in
association with , single and single at the LHC.
Measurements of the total cross sections are very sensitive to variations in
the Higgs-top couplings that are consistent with the present indirect
constraints, as are invariant mass distributions in , and
final states. We also investigate the additional information on
and that could be obtained from measurements of
the longitudinal and transverse polarization in the different associated
production channels, and the spin correlation in
events.Comment: 19 pages, 11 figure
THE COMMERCIAL POTENTIAL OF NEW DAIRY PRODUCTS FROM MEMBRANE TECHNOLOGY
Membrane filtration technologies are capable of creating entirely new, more functional food products. In this regard, potential new dairy products include high-protein, low-lactose fluid milk, high-protein, low-lactose ice cream, and non-far yogurt made with fewer stabilizers. An initial survey of membrane manufacturing companies determined the added cost to produce such functional food products to be two to six percent of the existing retail price for similar standard dairy products. A subsequent survey of milk processors found that the most likely adopters of such membrane technologies were yogurt manufacturers.Agribusiness,
Is the ’Linkage Principle’ Valid?: Evidence from the Field
revenue comparison, auction choice, linkage principle, used-car auctions
Quantification of Local Hemodynamic Alterations Caused by Virtual Implantation of Three Commercially Available Stents for the Treatment of Aortic Coarctation
Patients with coarctation of the aorta (CoA) are prone to morbidity including atherosclerotic plaque that has been shown to correlate with altered wall shear stress (WSS) in the descending thoracic aorta (dAo). We created the first patient-specific computational fluid dynamics (CFD) model of a CoA patient treated by Palmaz stenting to date, and compared resulting WSS distributions to those from virtual implantation of Genesis XD and modified NuMED CP stents, also commonly used for CoA. CFD models were created from magnetic resonance imaging, fluoroscopy and blood pressure data. Simulations incorporated vessel deformation, downstream vascular resistance and compliance to match measured data and generate blood flow velocity and time-averaged WSS (TAWSS) results. TAWSS was quantified longitudinally and circumferentially in the stented region and dAo. While modest differences were seen in the distal portion of the stented region, marked differences were observed downstream along the posterior dAo and depended on stent type. The Genesis XD model had the least area of TAWSS values exceeding the threshold for platelet aggregation in vitro, followed by the Palmaz and NuMED CP stents. Alterations in local blood flow patterns and WSS imparted on the dAo appear to depend on the type of stent implanted for CoA. Following confirmation in larger studies, these findings may aid pediatric interventional cardiologists in selecting the most appropriate stent for each patient, and ultimately reduce long-term morbidity following treatment for CoA by stenting
The Cost of Food Self-Sufficiency and Agricultural Protection in South Korea
As part of its food security policy, South Korea has been pursuing food self-sufficiency using high tariffs and high administrative prices in key agricultural and food markets. Using a dual approach to trade and trade restrictiveness indices, we analyze the impact of these market distortions on welfare and trade volume. Then, we compute optimum distortions, which minimize the welfare cost of observed self-sufficiency and production objectives. We rationalize these optimum distortions to what could be claimed as legitimate protection under a "food security" (FS) box in World Trade Organization negotiations. FS-box protection is sensitive to changes in the definition and the extent of the FS objectives. We show that FS via production targets and reliance on imports would be more palatable to consumers and trade partners, while preserving rents to the farm sector.agricultural distortions, food security, Korea, protection, targeting, WTO negotiations, Food Security and Poverty,
A Cost-Benefit Analysis of a Collections Inventory Project: A Statistical Analysis of Inventory Data from a Medium-sized Academic Library
Using an electronic shelf-reading system a cost-benefit analysis was conducted of an inventory/shelf-reading project in a medium-sized academic library. Analyses include time spent, cataloging discrepancies, books found with active statuses, mis-shelving rate and distance, and subsequent use of found books. Correctly re-shelving “missing” materials was found to be more cost-effective and service oriented than repurchase
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