Evidence for B^(*)_s Production at the Upsilon(5S)

Based on data collected by the CLEO III detector at CESR, we started a series of investigations to open the mysteries of the $\Upsilon$(5S) resonance decay properties. $B_s$ mesons are expected to decay predominantly into $D_s$ meson, while the lighter $B$ mesons decay into $D_s$ only about 10% of the time. We exploit this difference to present the first evidence of a substantial production of $B_s$ mesons at the $\Upsilon$(5S) resonance. We make here a preliminary model dependent estimate of the ratio of $B_s^{(*)}\bar{B}_s^{(*)}$ to the total $b\bar{b}$ quark pair production at the $\Upsilon$(5S) energy to be $(21\pm 3 \pm 9)$%.Comment: 3 pages, 3 figures, submitted to DPF 2004 conference proceedings, UC Riverside, C

Performance of a C4F8O Gas Radiator Ring Imaging Cherenkov Detector Using Multi-anode Photomultiplier Tubes

We report on test results of a novel ring imaging Cherenkov (RICH) detection system consisting of a 3 meter long gaseous C4F8O radiator, a focusing mirror, and a photon detector array based on Hamamatsu multi-anode photomultiplier tubes. This system was developed to identify charged particles in the momentum range from 3-70 GeV/c for the BTeV experiment.Comment: 28 pages, 23 figures, submitted to Nuclear Instruments and Method

Duality properties of indicatrices of knots

The bridge index and superbridge index of a knot are important invariants in knot theory. We define the bridge map of a knot conformation, which is closely related to these two invariants, and interpret it in terms of the tangent indicatrix of the knot conformation. Using the concepts of dual and derivative curves of spherical curves as introduced by Arnold, we show that the graph of the bridge map is the union of the binormal indicatrix, its antipodal curve, and some number of great circles. Similarly, we define the inflection map of a knot conformation, interpret it in terms of the binormal indicatrix, and express its graph in terms of the tangent indicatrix. This duality relationship is also studied for another dual pair of curves, the normal and Darboux indicatrices of a knot conformation. The analogous concepts are defined and results are derived for stick knots.Comment: 22 pages, 9 figure

Creatine is neuroprotective to retinal neurons in vitro but not in vivo

Purpose: To investigate the neuroprotective properties of creatine in the retina using in vitro and in vivo models of injury. Methods: Two different rat retinal culture systems (one containing retinal ganglion cells [RGC] and one not) were subjected to either metabolic stress, via treatments with the mitochondrial complex IV inhibitor sodium azide, or excitotoxic stress, via treatment with N-methyl-D-aspartate for 24 hours, in the presence or absence of creatine (0.5, 1.0, and 5.0 mM). Neuronal survival was assessed by immunolabeling for cell-specific antigens. Putative mechanisms of creatine action were investigated in vitro. Expression of creatine kinase (CK) isoenzymes in the rat retina was examined using Western blotting and immunohistochemistry. The effect of oral creatine supplementation (2%, wt/wt) on retinal and blood creatine levels was determined as well as RGC survival in rats treated with N-methyl-D-aspartate (NMDA; 10 nmol) or high IOP-induced ischemia reperfusion. Results: Creatine significantly prevented neuronal death induced by sodium azide and NMDA in both culture systems. Creatine administration did not alter cellular adenosine triphosphate (ATP). Inhibition of CK blocked the protective effect of creatine. Retinal neurons, including RGCs, expressed predominantly mitochondrial CK isoforms, while glial cells expressed exclusively cytoplasmic CKs. In vivo, NMDA and ischemia reperfusion caused substantial loss of RGCs. Creatine supplementation led to elevated blood and retinal levels of this compound but did not significantly augment RGC survival in either model. Conclusions: Creatine increased neuronal survival in retinal cultures; however, no significant protection of RGCs was evident in vivo, despite elevated levels of this compound being present in the retina after oral supplementation.Paul Ikgan Sia, John P. M. Wood, Glyn Chidlow, Robert Casso

An Upgraded Transverse Electromagnetic Parallel Plates for Dielectric Measurement

A new version of transverse electromagnetic parallel plates with irregular plates’ width and plate separation has been developed for dielectric measurement. The separations between the plates are supported by four rectangular Teflon block and 1 mm of groove is proposed at the center of the upper plate to maintain the measurement repeatability. The groove enables the samples which are slightly higher than 2 cm to be fitted well between the plates without introducing extra force to the plates. Theperformance of both parallel plates has been compared in the frequency range from 100 MHz to 1.1 GHz. It is found that the upgraded parallel plate offers better return loss and insertion loss above 500 MHz compared to the previous parallel plate. It is reported from this work that the return loss of the parallel plate must be lower than -15 dB in order to achieve accurate dielectric constant. However, the insertion loss of the parallel plates does not influence the real permeability significantly. The upgraded TEM parallel plateproduces a consistent reading with a standard deviation of less than 0.05 above frequency 200 MHz. The dielectric measurement of Polypropylene (PP) has proven the capability of this upgraded TEM parallelplate

Distribution and activity of mitochondrial proteins in vascular and avascular retinas: implications for retinal metabolism

Purpose:Understanding the energetics of retinal neurons and glia is crucial for developing therapies for diseases that feature deficits in nutrient or oxygen availability. Herein, we performed a detailed characterization of the distribution and activity of mitochondrial proteins in the vascularized retinas of rat and marmoset, and the avascular retinas of rabbit and guinea pig. Further, we delineated expression of ubiquitous mitochondrial creatine kinase (uMtCK). Methods:Expression of eight mitochondrial proteins was investigated using Western blotting, single- and double-labeling immunohistochemistry. Activities of cytochrome c oxidase, succinate dehydrgogenase, and isocitrate dehydrogenase were determined by enzyme histochemistry using unfixed tissue sections. Results:In vascularized retinas, immunoreactivities were characterized by strong, punctate labeling in the plexiform layers, photoreceptor inner segments, somas of various cell types, notably retinal ganglion cells (RGCs), and the basolateral surface of the retinal pigment epithelium. In avascular retinas, immunoreactivities featured intense labeling of inner segments, together with weak, but unambiguous, staining of both plexiform layers. RGCs were relatively enriched. In Müller cells of avascular retinas, mitochondria were restricted to scleral-end processes. For each species, enzyme activity assays yielded similar results to the protein distributions. Labeling for uMtCK in vascular and avascular retinas was fundamentally similar, being restricted to neuronal populations, most notably inner segments and RGCs. Of all of the mitochondrial proteins, uMtCK displayed the strongest labeling in avascular retinas. uMtCK was not detectable in Müller cells in any species. Conclusions:The current findings advance our understanding of the metabolic similarities and differences between vascular and avascular retinas.Glyn Chidlow, John P. M. Wood, Paul I. Sia, Robert J. Casso

A Stochastic Multi-scale Approach for Numerical Modeling of Complex Materials - Application to Uniaxial Cyclic Response of Concrete

In complex materials, numerous intertwined phenomena underlie the overall response at macroscale. These phenomena can pertain to different engineering fields (mechanical , chemical, electrical), occur at different scales, can appear as uncertain, and are nonlinear. Interacting with complex materials thus calls for developing nonlinear computational approaches where multi-scale techniques that grasp key phenomena at the relevant scale need to be mingled with stochastic methods accounting for uncertainties. In this chapter, we develop such a computational approach for modeling the mechanical response of a representative volume of concrete in uniaxial cyclic loading. A mesoscale is defined such that it represents an equivalent heterogeneous medium: nonlinear local response is modeled in the framework of Thermodynamics with Internal Variables; spatial variability of the local response is represented by correlated random vector fields generated with the Spectral Representation Method. Macroscale response is recovered through standard ho-mogenization procedure from Micromechanics and shows salient features of the uniaxial cyclic response of concrete that are not explicitly modeled at mesoscale.Comment: Computational Methods for Solids and Fluids, 41, Springer International Publishing, pp.123-160, 2016, Computational Methods in Applied Sciences, 978-3-319-27994-

Thermal Performance of Oil Palm Fibre and Paper Pulp as the Insulation Materials

Energy consumption for residential use in Malaysia is keep increasing yearly in order to maintain the internal thermal comfort of the building. Roof insulation material plays a vital role in improving the thermal comforts of the building while reduce the cooling load of the building. Oil palm industry in Malaysia had grown aggressively over the past few decades. Tons of oil palm waste had produced during the process such as empty fruit bunch fiber. Another waste material that available and easy to obtain is paper. Paper is a valuable material that can be recycled. Waste paper comes from different sources such as newspaper, office and printing papers. This study will take advantage of the available resources which could contribute to reduce the environment impact. The aim of this study is to investigate the thermal performance of roof insulation materials using mixture of oil palm fiber and paper pulp with different ratio and thickness. This study found that the thermal performance of the paper pulp is slightly better compare to the oil palm fiber. Thermal conductivity of the particle board reduces around 4.1% by adding the 10% of paper pulp into the total density of the particle board. By adding 75% of paper pulp, the thermal conductivity of the particle board could be reduced to 24.6% compare to the oil palm fiber board under the similar condition. Therefore, from this study, it could be concluded that paper pulp has high potential to be used as a building insulation material