Dilepton p T suppression in the color glass condensate

Dilepton production is investigated in proton-nucleus collisions in the forward region using the color glass condensate approach. The transverse momentum distribution (p_T), more precisely the ratio between proton-nucleus and proton-proton differential cross section for LHC energies is evaluated, showing the effects of saturation at small p_T, and presenting a suppression of the Cronin type peak at moderate p_T. These features indicate the dilepton as the most suitable probe to study the properties of the saturated regime and the Cronin effect in these systems.Arrival of the final proofs: 4 July 2005PACS: 11.15.Kc, 24.85. + p     

The neuroblast and angioblast chemotaxic factor SDF-1 (CXCL12) expression is briefly up regulated by reactive astrocytes in brain following neonatal hypoxic-ischemic injury

Background  

Stromal cell-derived factor 1 (SDF-1 or CXCL12) is chemotaxic for CXCR4 expressing bone marrow-derived cells. It functions in brain embryonic development and in response to ischemic injury in helping guide neuroblast migration and vasculogenesis. In experimental adult stroke models SDF-1 is expressed perivascularly in the injured region up to 30 days after the injury, suggesting it could be a therapeutic target for tissue repair strategies. We hypothesized that SDF-1 would be expressed in similar temporal and spatial patterns following hypoxic-ischemic (HI) injury in neonatal brain.     

Normal binomials over algebraic number fields

In this paper, normal and weakly normal binomials over an arbitrary algebraic number field will be characterized. Explicit results on the possible degrees of such binomials are given. Several examples conclude the paper.     

Use of flame atomic absorption spectrometry and the effect of water chemistry for the study of the bioaccumulation of cadmium in Menidia beryllina (cope), the tidewater silverside

In laboratory controlled experiments using Menidia beryllina, the Tidewater Silverside (fish), it was shown that the salinity of the water affects accumulation of cadmium. The concentration of cadmium was determined using a previously described flame atomic absorption spectrometric method. In general, the higher the salinity, the less cadmium is accumulated in fish. At low or no salinity, higher concentrations of cadmium are found in fish. Elimination of cadmium occurred at a faster rate in fish exposed to higher levels of salinity. It is proposed that the low bioaccumulation of cadmium in high saline waters was due to competition between the free Cd²⁺ ion, Ca²⁺, and Cl⁻ ion preventing Cd²⁺ from entering fish.     

A micro electron capture detector for temperature programmed analysis with capillary columns for a wide range of applications

Summary The electron capture detector (ECD) has become a indispensable and widely used tool for the detection of halogenated compounds in gas chromatography. The ECD is successfully used for routine analysis particularly in the field of environmental survey, residue determination in the food and agriculture chemistry and even more so in clinical chemistry. However, its application with high resolution glass capillary columns revealed a substantial drawback of existing ECD's, primarily the relatively large internal detector volume. The micro ECD described, with its very small cell volume (140 mm³), particularly designed for use with high resolution capillary columns, minimizes drastically the loss of separation efficiency since diffusion effects are negligible. The micro ECD permits the use of splitless or split injection techniques, as well as temperature programmed analysis to optimize sample separation. Very stable baseline and low noise conditions lower the detection limits considerably (2 pg Lindane full scale). The micro ECD can be operated either with direct current, pulsed frequency or constant current modes. Examples demonstrating the capabilities of this detector include the detection of halogenated organic volatiles in water at subnanogram levels, the determination of PCB's and pesticide residues in food as well as selected analysis in clinical chemistry, such as bile acids and amino acids in body fluids.     

The electron-impact-induced fragmentations of some substituted 3-aminopropionitriles

As a part of our study of the chemistry of simulated Jovian atmospheres, we have synthesized a series of twelve alkyl aminopropionitriles to serve as model compounds. The spectra of these compounds have been obtained, and the transitions which are observed have been further investigated by scanning in the metastable mode and by obtaining the spectra of deuterium labeled 3-(N-ethylamino)propionitrile. The fragmentations which are observed are dominated by the amine group.     

Assignments of normally unoccupied orbitals to the temporary negative ion states of several lanthanide NMR shift reagents and comments on resonance involvement in electron circular dichroism

We have measured the total electron scattering cross sections of several NMR shift reagent molecules X(hfc)3, where X = Yb, Er, Eu and Pr, by means of electron transmission spectroscopy (ETS) to determine their vertical attachment energies. A strong low-energy resonance (<1 eV) is observed in all of the compounds except for Yb(hfc)3. We explain this anomaly in terms of the ground-state electron configuration of each molecule. Also, with the aid of restricted open-shell Hartree-Fock (ROHF) calculations on analogous molecules with truncated fluorocarbon chains, we have assigned specific normally unoccupied orbitals to the resonances observed in ETS. To our knowledge, these molecules are the largest for which this procedure has been successfully completed. Nolting et al. (J. Phys. B 1997, 30, 5491) have demonstrated that the above NMR shift reagents exhibit electron circular dichroism (ECD) between 1 and 10 eV. Using our new total cross section data, we comment on the possibility of resonance involvement in the generation of ECD.     

Slippery or sticky boundary conditions: control of wrinkling in metal-capped thin polymer films by selective adhesion to substrates

Wrinkling patterns at the metallized surface of thin polymer films are shown to be sensitive to the sticky or slippery character of the polymer-substrate interface. Existing theoretical models were expanded to specific boundary conditions (adhesive versus slippery) in order to rationalize these observations. Based on this concept, we were able to propose a new and simple method to orient the wrinkles by chemically patterning the substrate with regions of high and low adhesion.