Rapidity equilibration and longitudinal expansion at RHIC

The evolution of net-proton rapidity spectra with sqrt(s_NN) in heavy relativistic systems is proposed as an indicator for local equilibration and longitudinal expansion. In a Relativistic Diffusion Model, bell-shaped distributions in central collisions at AGS energies and double-humped nonequilibrium spectra at SPS show pronounced longitudinal collective expansion when compared to the available data. The broad midrapidity valley recently discovered at RHIC in central Au+Au collisions at sqrt(s_NN) = 200 GeV indicates rapid local equilibration which is most likely due to deconfinement, and fast longitudinal expansion of the locally equilibrated subsystem. A prediction is made for Au+Au at sqrt(s_NN)= 62.4 GeV.Comment: 11 pages, 1 table, 2 figures; changes/additions in text, table, fig

Derived factorization categories of non-Thom–Sebastiani-type sums of potentials

We first prove semi-orthogonal decompositions of derived factorizationcategories arising from sums of potentials of gauged Landau-Ginzburg models,where the sums are not necessarily Thom--Sebastiani type. We then apply theresult to the category ${\rm HMF}^{L_f}(f)$ of maximally graded matrixfactorizations of an invertible polynomial $f$ of chain type, and explicitlyconstruct a full strong exceptional collection $E_1$,..., $E_{\mu}$ in {\rmHMF}^{L_f}(f) whose length $\mu$ is the Milnor number of theBerglund--H\"ubsch transpose $\widetilde{f}$ of $f$. This proves a conjecture,which postulates that for an invertible polynomial $f$ the category {\rmHMF}^{L_f}(f) admits a tilting object, in the case when $f$ is a chainpolynomial. Moreover, by careful analysis of morphisms between the exceptionalobjects $E_i$, we explicitly determine the quiver with relations $(Q,I)$ whichrepresents the endomorphism ring of the associated tilting object$\oplus_{i=1}^{\mu}E_i$ in ${\rm HMF}^{L_f}(f)$, and in particular we obtain anequivalence ${\rm HMF}^{L_f}(f)\cong {\rm D}^{\rm b}({\rm mod}\, kQ/I)$.<br

Pseudorapidity dependence of parton energy loss in relativistic heavy ion collisions

We analyze the recent data from the BRAHMS Collaboration on the pseudorapidity dependence of nuclear modification factors in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV by using the full three dimensional hydrodynamic simulations for the density effects on parton energy loss. We first compute the transverse spectra at $\eta=0$ and 2.2, and next take a ratio $R_{\eta}=R_{AA}(\eta=2.2)/R_{AA}(\eta=0)$, where $R_{AA}$ is a nuclear modification factor. It is shown that hydrodynamic components account for $R_{\eta}\simeq 1$ at low $p_\mathrm{T}$ and that quenched pQCD components lead $R_{\eta} < 1$ at high $p_\mathrm{T}$ which are consistent with the data. Strong suppression at $\eta=2.2$ is compatible with the parton energy loss in the final state.Comment: 5 pages, 4 figures; one figure adde

Electron-muon correlation as a new probe to strongly interacting quark-gluon plasma

As a new and clean probe to the strongly interacting quark-gluon plasma (sQGP), we propose an azimuthal correlation of an electron and a muon which originate from the semileptonic decay of charm and bottom quarks. By solving the Langevin equation for the heavy quarks under the hydrodynamic evolution of the hot plasma, we show that substantial quenching of the away-side peak in the electron-muon correlation can be seen if the sQGP drag force acting on heavy quarks is large enough as suggested from the gauge/gravity correspondence. The effect could be detected in high-energy heavy-ion collisions at the Relativistic Heavy Ion Collider and the Large Hadron Collider.Comment: 4 pages, 2 figure

The effect of different fertilizer application levels on anthocyanoplast development in berry skin of Pione grapevines (V. vinifera x V. labrusca)

Effects of different levels of a complete liquid fertilizer on grape berry coloration and anthocyanoplast (ACP) development in the skin were investigated. Four-year-old vines of cv. Pione (a tetraploid hybrid of Vitis vinifera L. and V. labrusca L.) were planted in root zone-restricted beds and were treated with normal (N), high (H; Nx1.5), and excessively high (EH; Nx2) levels of a commercial liquid fertilizer. Fertilizer levels were decreased to one third after veraison to accelerate berry ripening. Skin anthocyanin contents in N- and H-treated berries increased at a constant rate after veraison, while the contents in EH berries were significantly lower. ACPs were first observed in epidermal cells at veraison in N and H berries and 2 weeks later in EH berries. In each treatment formation of ACPs in hypodermal cells occurred one week later than in epidermal cells. In each treatment the number of epidermal cells containing ACPs increased during ripening of the berries but the number of hypodermal cells with ACPs increased only in N vines. The average numbers of ACPs per epidermal and hypodermal cell were largest in N vines, followed by H and EH vines (two weeks after veraison). The number of ACPs decreased thereafter because most ACPs coalesced. The average ACP diameter at full ripeness was 16.7 μm in N vines, whereas in H and EH vines it was 9.5 μm and 9.7 μm, respectively. From these results, it can be deduced that in Pione grape berries high fertilizer levels inhibit ACP formation both in epidermal and hypodermal cells at veraison and/or induce their coalescence thereafter, resulting in poor coloration.

Theoretical Study of Friction: A Case of One-Dimensional Clean Surfaces

A new method has been proposed to evaluate the frictional force in the stationary state. This method is applied to the 1-dimensional model of clean surfaces. The kinetic frictional force is seen to depend on velocity in general, but the dependence becomes weaker as the maximum static frictional force increases and in the limiting case the kinetic friction gets only weakly dependent on velocity as described by one of the laws of friction. It is also shown that there is a phase transition between state with vanishing maximum static frictional force and that with finite one. The role of randomness at the interface and the relation to the impurity pinning of the sliding Charge-Density-Wave are discussed. to appear in Phys.Rev.B. abstract only. Full text is available upon request. E-mail: [email protected]: 2 pages, Plain TEX, OUCMT-94-

Effect of anthocyanin composition in grape skin on anthocyanic vacuolar inclusion development and skin coloration

Berry skin coloration, the content and composition of anthocyanin and anthocyanic vacuolar inclusion (AVI) development were investigated in two black cultivars, Cabernet Sauvignon (Vitis vinifera) and Pione (V. vinifera × V. labrusca, 4x), and one red cv., Red Port (V. vinifera × V. labrusca). Pione had lower L* (lightness of the skin) and higher color index values than Cabernet Sauvignon, indicating that Pione had darker skin color than Cabernet Sauvignon. The two black cultivars had high contents of malvidin, while the major anthocyanidin of Red Port was cyanidin and delphinidin. This difference of anthocyanidin composition was responsible for the red color of Red Port. Whereas the anthocyanidin composition of the two black cultivars showed little difference, the percentage of acylated anthocyanins was markedly higher in Pione than in Cabernet Sauvignon. The diameter of AVIs was similar between Pione and Cabernet Sauvignon, but the density of AVIs was higher in cv. Pione. This difference in AVI development affects grape skin coloration. A comparison of the anthocyanin composition in isolated AVIs and that in whole cell tissue showed that in all three cultivars the percentage of acylated anthocyanins was high in the AVIs. In Pione skins the high percentage of acylated anthocyanins might result in many AVIs to be formed, and might be responsible for the dark coloration.

Effects of water deficit stress on leaf and berry ABA and berry ripening in Chardonnay grapevines (Vitis vinifera)

Chardonnay vines planted in root zone restricting beds were subjected to water deficit stress by withholding irrigation for a period starting at 15 (early stress; ES) or 25 d (late stress; LS) after veraison and lasting until harvest. Control vines were provided with normal irrigation. Both ES and LS treatments significantly decreased leaf water potential and caused leaf wilting 2 d after the start of each treatment. ABA levels in fruit zone leaves increased significantly 4 and 5 d after the onset of LS and ES treatments, respectively. After 2 d of ES treatment, the berry ABA level greatly increased, while LS and control treatments resulted in a gradual increase in berry ABA. In ES-treated vines, clusters were harvested 10 d after the onset of treatment, 10 d earlier than in LS and control vines, due to the severe berry shrinking and leaf fall. Levels of juice TSS, fructose, glucose, and malate were generally lower than those of LS and control vines. Both ES and LS treatments resulted in significantly higher amino acid levels. The level of proline, however, the amino acid with highest amounts in Chardonnay grape berries, was lowest in ES-treated vines. This study reveals that the effect of water deficit stress on berry ripening of Chardonnay is different depending on the stage of berry ripening, which might be caused by different ABA levels in berries.

Unitary Theory of Evaporating 2D Black Holes

We study a manifestly unitary formulation of 2d dilaton quantum gravity based on the reduced phase space quantization. The spacetime metric can be expanded in a formal power series of the matter energy-momentum tensor operator. This expansion can be used for calculating the quantum corrections to the classical black hole metric by evaluating the expectation value of the metric operator in an appropriate class of the physical states. When the normal ordering in the metric operator is chosen to be with respect to Kruskal vacuum, the lowest order semiclassical metric is exactly the one-loop effective action metric discovered by Bose, Parker and Peleg. The corresponding semiclassical geometry describes an evaporating black hole which ends up as a remnant. The calculation of higher order corrections and implications for the black hole fate are discussed.Comment: LaTex fil

Artificial pollination in Vitis coignetiae Pulliat

Artificial pollination experiments were conducted on female vines of Vitis coignetiae and the effects of pollen variety and pollination methods on pollen tube growth were analyzed. Pollination by dusting pure pollen from Muscat of Alexandria (V. vinifera), Cabernet Sauvignon (V. vinifera), Campbell Early (V. vinifera x V. labrusca) and male V. coignetiae vines resulted in a large number of pollen tubes penetrating the stigma and an average of more than four tubes per pistil reached the micropyles. Dry pollinations with pollen from Muscat of Alexandria diluted in powdered milk or Lycopodium spores at the proportion of 1:2 or 1:10 (pollen : diluent w/w) resulted in pistils with ca. 140 to 250 pollen grains on the stigma. Forty to 60 pollen tubes per pistil penetrated the style and foils or more pollen tubes reached micropyles in all treatments. Clusters sprayed with or dipped in a 10 % sucrose solution containing 0.1, 0.5 or 1.0 g pollen/l produced stigmas with an average of 5.2 to 38.5 pollen grains. Pollen germination was poor both for spray and dipping treatments and less than one pollen tube per pistil reached micropyles for any of the pollen concentration used