Shadowing and Absorption Effects on J/psi Production in dA Collisions

We study medium modifications of J/psi production in cold nuclear media in deuterium-nucleus collisions. We discuss several parameterizations of the modifications of the parton densities in the nucleus, known as shadowing, an initial-state effect. We also include absorption of the produced J/psi by nucleons, a final-state effect. Both spatially homogeneous and inhomogeneous shadowing and absorption are considered. We use the number of binary nucleon-nucleon collisions as a centrality measure. Results are presented for d+Au collisions at sqrt{S_{NN}} = 200 GeV and for d+Pb collisions at sqrt{S_{NN}} = 6.2 TeV. To contrast the centrality dependence in pA and dA collisions, we also present pPb results at sqrt{S_{NN}} = 8.8 TeV.Comment: 22 pages, 11 figures, uses revte

Cold Nuclear Matter Effects on J/psi and Upsilon Production at the LHC

The charmonium yields are expected to be considerably suppressed if a deconfined medium is formed in high-energy heavy-ion collisions. In addition, the bottomonium states, with the possible exception of the Upsilon(1S) state, are also expected to be suppressed in heavy-ion collisions. However, in proton-nucleus collisions the quarkonium production cross sections, even those of the Upsilon(1S), are also suppressed. These "cold nuclear matter" effects need to be accounted for before signals of the high density QCD medium can be identified in the measurements made in nucleus-nucleus collisions. We identify two cold nuclear matter effects important for midrapidity quarkonium production: "nuclear absorption", typically characterized as a final-state effect on the produced quarkonium state and shadowing, the modification of the parton densities in nuclei relative to the nucleon, an initial-state effect. We characterize these effects and study the energy, rapidity, and impact-parameter dependence of initial-state shadowing in this paper.Comment: to be published in Phys. Rev.

Suited for spacewalking: A teacher's guide with activities

This publication is an activity guide for teachers on spacesuits and spacewalking. It uses the intensive interest many children have in space exploration as a launching point for hands-on-opportunities. The guide begins with brief discussions of the space environment, the history of space walking, the Space Shuttle spacesuit, and working in space. These are followed by a series of activities that enable children to explore the space environment as well as the science and technology behind the functions of spacesuits. The activities are not rated for specific grade levels because they can be adapted for students of many ages. The guide concludes with a brief glossary as well as references and resources

Microgravity: a Teacher's Guide with Activities, Secondary Level

This NASA Educational Publication is a teacher's guide that focuses on microgravity for the secondary level student. The introduction answers the question 'What is microgravity?', as well as describing gravity and creating microgravity. Following the introduction is a microgravity primer which covers such topics as the fluid state, combustion science, materials science, biotechnology, as well as microgravity and space flight. Seven different activities are described in the activities section and are written by authors prominent in the field. The concluding sections of the book include a glossary, microgravity references, and NASA educational resources

Parton densities and structure functions at next-to-next-to-leading order and beyond

We summarize recent results on the evolution of unpolarized parton densities and deep-inelastic structure functions in massless perturbative QCD. Due to last year's extension of the integer-moment calculations of the three-loop splitting functions, the NNLO evolution of the parton distributions can now be performed reliably at momentum fractions x >= 10^-4, facilitating a considerably improved theoretical accuracy of their extraction from data on deep-inelastic scattering. The NNLO corrections are not dominated, at relevant values of x, by their leading small-x terms. At large x the splitting-function series converges very rapidly, hence, employing results on the three-loop coefficient functions, the structure functions can be analysed at N^3LO for x > 10^-2. The resulting values for alpha_s do not significantly change beyond NNLO, their renormalization scale dependence reaches about +-1% at N^3LO.Comment: 10 pages, LaTeX, 6 figures. Talk presented at the workshops `New Trends in HERA Physics 2001', Ringberg Castle (Germany), June 2001 and `DIS 2001', Bologna (Italy), April 2001. To appear, slightly shortened in the latter case, in the proceeding

AN ECONOMIC ANALYSIS OF THE DAIRY ENVIRONMENTAL COOPERATIVE IN NORTHEAST KANSAS

In 1997, the Black Vermillion Dairy Environmental Cooperative (DEC) was started with an EPA 319A grant. Ten Kansas dairies located in the Kansas Black Vermillion Watershed were studied to evaluate the on-farm manure structures cost-shared by the DEC. Net present value (NPV) analysis was used to evaluate the profitability associated with the manure structures. The NPV analysis showed that in most cases, investing in a manure storage structure is a worthwhile venture and can be profitable for the dairy. However, cost-share assistance often will be needed in order to have positive pre-tax and after-tax NPVs.Dairy Environmental Cooperative (DEC), manure management, Net Present Value (NPV) analysis, cost-share, concrete manure storage, Environmental Economics and Policy,

NNLO evolution of deep-inelastic structure functions: the singlet case

We study the next-to-next-to-leading order (NNLO) evolution of flavour singlet parton densities and structure functions in massless perturbative QCD. Present information on the corresponding three-loop splitting functions is used to derive parametrizations of these quantities, including Bjorken-x dependent estimates of their residual uncertainties. Compact expressions are also provided for the exactly known, but in part rather lengthy two-loop singlet coefficient functions. The size of the NNLO corrections and their effect on the stability under variations of the renormalization and mass-factorizations scales are investigated. Except for rather low values of the scales, the residual uncertainty of the three-loop splitting functions does not lead to relevant effects for x > 10^-3. Inclusion of the NNLO contributions considerably reduces the theoretical uncertainty of determinations of the quark and gluon densities from deep-inelastic structure functions.Comment: 31 pages, LaTeX, 14 eps-figure

Interaktionen zwischen Genotyp und Ort sind ein Vorteil von lokaler Züchtung von Ackerbohnen (Vicia faba L.)

Organic farming is based on low productivity environments regarding the restricted supply of inputs. Thus, to maximize the response of selection, the local breeding approach was put forward for organic agriculture. To analyse this approach, efforts of organic farmers and scientists were combined in a pertinent, participatory breeding approach using spring faba bean as crop. A set of genotypes with different levels of heterozygosity and heterogeneity were tested in four organic farms and one conventional location. Results for grain yield showed that the genotype-location interaction was highly significant and contributed to a large extent to the yield variation. The findings indicated that indeed local breeding programs could give greater genetic gains for organic cropping systems than traditional, formal plant breeding programs