Strangeness Content in the Nucleon

I review recent studies of strangeness content in the nucleon pertaining to the flavor-singlet $g_A^0$, the $\bar{s}s$ matrix element and the strangeness electric and magnetic form factors $G_E^s(q^2)$ and $G_M^s(q^2)$, based on lattice QCD calculations. I shall also discuss the relevance of incorporating the strangeness content in nuclei in regard to strange baryon-antibaryon productions from proton-nucleus and nucleus-nucleus collisions at SPS and RHIC energies.Comment: 11 pages, 4 figures, Invited talk at V Int. Conf. on Strangeness in Quark Matter, Berkeley, CA, July 20--25, 200

Anisotropic strain and phonon deformation potentials in GaN

We report optical phonon frequency studies in anisotropically strained c-plane- and a-plane-oriented GaN films by generalized infrared spectroscopic ellipsometry and Raman scattering spectroscopy. The anisotropic strain in the films is obtained from high-resolution x-ray diffraction measurements. Experimental evidence for splitting of the GaN E1(TO), E1(LO), and E2 phonons under anisotropic strain in the basal plane is presented, and their phonon deformation potentials cE1(TO) , cE1(LO) , and cE2 are determined. A distinct correlation between anisotropic strain and the A1(TO) and E1(LO) frequencies of a-plane GaN films reveals theaA1TO, bA1TO, aE1LO, andbE1LO phonon deformation potentials. The aA1TO and bA1TOaA1TO and aE1LO phonon deformation potentials agree well with recently reported theoretical estimations [J.-M. Wagner and F. Bechstedt, Phys. Rev. B 66, 115202 (2002)], while bA1TO and bE1LO are found to be significantly larger than the theoretical values. A discussion of the observed differences is presented

Čvrsta disperzija meloksikama: faktorijalno dizajnirani dozirani pripravak za gerijatrijsku populaciju

The objective of the present work was to improve the dissolution properties of the poorly water-soluble drug meloxicam by preparing solid dispersions with hydroxyethylcellulose (HEC), mannitol and polyethylene glycol (PEG) 4000 and to develop a dosage form for geriatric population. Differential scanning calorimetry, X–ray diffractometry, Fourier transform infrared spectroscopy and scanning electron microscopy were used to investigate the solid-state physical structure of the prepared solid dispersions. Higher in vitro dissolution of solid dispersions was recorded compared to their corresponding physical mixtures and the pure drug. PEG 4000 in 1:9 drug to carrier ratio exhibited the highest drug release (100.2%), followed by mannitol (98.2%) and HEC (89.5%) in the same ratio. Meloxicam-PEG 4000 solid dispersion was formulated into suspension and optimization was carried out by 23 factorial design. Formulations containing higher levels of methyl cellulose and higher levels of either sodium citrate or Tween 80 exhibited the highest drug release.Cilj rada bio je poboljšati topljivost meloksikama u vodi pripravom čvrstih disperzija s hidroksietilcelulozom (HEC), manitolom i polietilen glikolom 4000 (PEG 4000) te razviti dozirani pripravaka za gerijatrijsku populaciju. Za ispitivanje fizičke strukture pripravljenih čvrstih disperzija korištene su diferencijalna pretražna kalorimetrija, difraktometrija rentgentskim zrakama, FTIR i pretražna elektronska mikroskopija. Čvrste disperzije su u in vitro uvjetima pokazale bolju topljivost u odnosu na fizičku smjesu i čistu ljekovitu tvar. Najbolje oslobađanje lijeka (100,2%). postignuto je iz disperzija s PEG 4000 (omjer ljekovite tvari i nosača 1:9). Slijede manitol (98,2%) i HEC (89,5%) (isti omjer meloksikama i polimera). Čvrsta disperzija meloksikama s PEG 4000 prevedena je u suspenziju te optimirana 23 faktorijalnim dizajnom. Najbolje oslobađanje ljekovite tvari postignuto je iz pripravaka koji sadrže veći udio etilceluloze i natrijevog citrata, odnosno Tween 80

Centrality dependence of the expansion dynamics in Pb-Pb collisions at 158 A GeV/c

Two-particle correlation functions of negatively charged hadrons from Pb-Pb collisions at 158 GeV/c per nucleon have been measured by the WA97 experiment at the CERN SPS. A Coulomb correction procedure that assumes an expanding source has been implemented. Within the framework of an expanding thermalized source model the size and dynamical state of the collision fireball at freeze-out have been reconstructed as a function of the centrality of the collision. Less central collisions exhibit a different dynamics than central ones: both transverse and longitudinal expansion velocities are slower, the expansion duration is shorter and the system freezes out showing smaller dimensions and higher temperature.Comment: 22 pages, 11 figures, Te

Dynamical quantum noise in Bose-Einstein condensates

We introduce the study of dynamical quantum noise in Bose-Einstein condensates through numerical simulation of stochastic partial differential equations obtained using phase space representations. We derive evolution equations for a single trapped condensate in both the positive-$P$ and Wigner representations, and perform simulations to compare the predictions of the two methods. The positive-$P$ approach is found to be highly susceptible to the stability problems that have been observed in other strongly nonlinear, weakly damped systems. Using the Wigner representation, we examine the evolution of several quantities of interest using from a variety of choices of initial state for the condensate, and compare results to those for single-mode models.Comment: 8 figures, submitted to Phys. Rev.

Habitual intake of flavonoid subclasses and risk of colorectal cancer in two large prospective cohorts

Background: Flavonoids inhibit the growth of colon cancer cells in vitro. In a secondary analysis of a randomized controlled trial, the Polyp Prevention Trial, a higher intake of one sub-class, flavonols, was significantly associated with reduced risk of recurrent advanced adenoma. Most previous prospective studies on colorectal cancer evaluated only a limited number of flavonoid sub-classes and intake ranges, yielding inconsistent results.  Objective: To examine whether higher habitual dietary intakes of flavonoid subclasses (flavonols, flavones, flavanones, flavan-3-ols and anthocyanins) are associated with lower risk of colorectal cancer.  Design: Using data from validated food frequency questionnaires administered every four years and an updated flavonoid food composition database flavonoid intakes were calculated for 42,478 male participants from the Health Professionals Follow-up Study and for 76,364 female participants from the Nurses’ Health Study.  Results: During up to 26 years of follow-up, 2,519 colorectal cancer cases (1,061 in men, 1,458 in women) were documented. Intakes of flavonoid subclasses were not associated with risk of colorectal cancer in either cohort. Pooled multivariable adjusted relative risks (95% confidence interval) comparing the highest with the lowest quintile were 1.04 (0.91, 1.18) for flavonols; 1.01 (0.89, 1.15) for flavones; 0.96 (0.84, 1.10) for flavanones; 1.07 (0.95, 1.21) for flavan-3-ols; and 0.98 (0.81, 1.19) for anthocyanins (all p-values for heterogeneity by sex >0.19). In subsite analyses, flavonoid intake was also not associated with colon or rectal cancer risk.  Conclusion: Our findings do not support the hypothesis that a higher habitual intake of any flavonoid sub-class decreases the risk of colorectal cancer

Multi-band high resolution spectroscopy rules out the hot Jupiter BD+20 1790b - First data from the GIARPS Commissioning

Context. Stellar activity is currently challenging the detection of young planets via the radial velocity (RV) technique. Aims. We attempt to definitively discriminate the nature of the RV variations for the young active K5 star BD+20 1790, for which visible (VIS) RV measurements show divergent results on the existence of a substellar companion. Methods. We compare VIS data with high precision RVs in the near infrared (NIR) range by using the GIANO - B and IGRINS spectrographs. In addition, we present for the first time simultaneous VIS-NIR observations obtained with GIARPS (GIANO - B and HARPS - N) at Telescopio Nazionale Galileo (TNG). Orbital RVs are achromatic, so the RV amplitude does not change at different wavelengths, while stellar activity induces wavelength-dependent RV variations, which are significantly reduced in the NIR range with respect to the VIS. Results. The NIR radial velocity measurements from GIANO - B and IGRINS show an average amplitude of about one quarter with respect to previously published VIS data, as expected when the RV jitter is due to stellar activity. Coeval multi-band photometry surprisingly shows larger amplitudes in the NIR range, explainable with a mixture of cool and hot spots in the same active region. Conclusions. In this work, the claimed massive planet around BD+20 1790 is ruled out by our data. We exploited the crucial role of multi- wavelength spectroscopy when observing young active stars: thanks to facilities like GIARPS that provide simultaneous observations, this method can reach its maximum potential.Comment: 12 pages, 7 figure

Study of the transverse mass spectra of strange particles in Pb-Pb collisions at 158 A GeV/c

The NA57 experiment has collected high statistics, high purity samples of \PKzS and \PgL, $\Xi$ and $\Omega$ hyperons produced in Pb-Pb collisions at 158 $A$ GeV/$c$. In this paper we present a study of the transverse mass spectra of these particles for a sample of events corresponding to the most central 53% of the inelastic Pb-Pb cross-section. We analyse the transverse mass distributions in the framework of the blast-wave model for the full sample and, for the first time at the SPS, as a function of the event centrality.Comment: 22 pages, 14 figures, submitted to J. Phys. G: Nucl. Phy