Einstein Supergravity and New Twistor String Theories

A family of new twistor string theories is constructed and shown to be free from world-sheet anomalies. The spectra in space-time are calculated and shown to give Einstein supergravities with second order field equations instead of the higher derivative conformal supergravities that arose from earlier twistor strings. The theories include one with the spectrum of N = 8 supergravity, another with the spectrum of N = 4 supergravity coupled to N = 4 super-Yang-Mills, and a family with N ≥ 0 supersymmetries with the spectra of self-dual supergravity coupled to self-dual super-Yang-Mills. The non-supersymmetric string with N = 0 gives self-dual gravity coupled to self-dual Yang-Mills and a scalar. A three-graviton amplitude is calculated for the N = 8 and N = 4 theories and shown to give a result consistent with the cubic interaction of Einstein supergravity.     

A Baby Steps/Giant Steps Probabilistic Algorithm for Computing Roadmaps in Smooth Bounded Real Hypersurface

We consider the problem of constructing roadmaps of real algebraic sets. This problem was introduced by Canny to answer connectivity questions and solve motion planning problems. Given s polynomial equations with rational coefficients, of degree D in n variables, Canny’s algorithm has a Monte Carlo cost of sⁿlog(s)D^O(n2)s^{n}\log(s)D^{O(n^{2})} operations in ℚ; a deterministic version runs in time sⁿlog(s)D^O(n4)s^{n}\log(s)D^{O(n^{4})} . A subsequent improvement was due to Basu, Pollack, and Roy, with an algorithm of deterministic cost s^d+1D^O(n2)s^{d+1}D^{O(n^{2})} for the more general problem of computing roadmaps of a semi-algebraic set (d≤n is the dimension of an associated object).     

Calcium phosphate mineralization controlled by carboxymethyl cellulose-g-polymethacrylic acid

Carboxymethyl cellulose-grafted polymethacrylic acid (CMC-g-PMAA) was synthesized by graft copolymerization process onto carboxymethyl cellulose backbone using methacrylic acid as a monomer and ammonium persulfate as a free radical initiator. CMC-g-PMAA was employed as dispersed template for controlling calcium phosphate mineralization from aqueous solutions at different copolymer contents and pHs. Hybrids with different morphologies and particles diameter were investigated by adjusting of preparation conditions. Synthesized hybrids were characterized by FT-IR, SEM, XRD, and particle size analyzer. Such functionalized hybrids with complex morphologies can be manipulated as a novel reinforcing fillers, ceramic precursors, or biomedical implants.     

Testing Sign Conditions on a Multivariate Polynomial and Applications

Let f be a polynomial in of degree D. We focus on testing the emptiness and computing at least one point in each connected component of the semi-algebraic set defined by f > 0 (or f < 0 or f ≠ 0). To this end, the problem is reduced to computing at least one point in each connected component of a hypersurface defined by f − e = 0 for positive and small enough. We provide an algorithm allowing us to determine a positive rational number e which is small enough in this sense. This is based on the efficient computation of the set of generalized critical values of the mapping which is the union of the classical set of critical values of the mapping f and the set of asymptotic critical values of the mapping f. Then, we show how to use the computation of generalized critical values in order to obtain an efficient algorithm deciding the emptiness of a semi-algebraic set defined by a single inequality or a single inequation. At last, we show how to apply our contribution to determining if a hypersurface contains real regular points. We provide complexity estimates for probabilistic versions of the latter algorithms which are within arithmetic operations in . The paper ends with practical experiments showing the efficiency of our approach on real-life applications.      

The 46, 48, 50Ti(p, α) 43, 45, 47Sc reactions at 40.35 MeV

The ^{46, 48, 50}Ti(p, α) ^{43, 45, 47}Sc reactions have been studied at a proton energy of 40.35 MeV with an overall energy resolution of about 80 keV FWHM. Angular distributions for states with excitation energies up to about 7 MeV in ⁴³Sc and ⁴⁵Sc and up to 8.4 MeV in ⁴⁷Sc are presented. Both positive- and negative-parity states were observed. A microscopic form factor formalism for the three-nucleon transfer reaction was applied to extract quantitative information. Zeroth order calculations have been performed assuming the simplest possible configuration for the transferred nucleons. Subsequently, the ($\text{1}\text{f}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{n}}$ shell-model wave functions of Kutschera et al. have been used in a more detailed test, considering the components with different neutron angular momentum couplings. Reasonable agreement was obtained for most of the states considered. The effect on the calculated analyzing power of including different configurations for the $\text{7}\text{2}{}^{\mathrm{?}}$ g.s. transition in ⁴⁷Sc was found to be small.     

IL-21 as a Predictor of Sustained Virologic Response in Patients with Chronic Hepatitis C Virus Infection

Fatty acid desaturases (FADs) catalyze the introduction of a double bond into acyl chains. Two FAD groups have been identified in plants: acyl-acyl carrier proteins (ACPs) and acyl-lipid or membrane-bound FAD. The former catalyze the conversion of 18:0 to 18:1 and to date have only been identified in plants. The latter are found in eukaryotes and bacteria and are responsible for multiple desaturations. In this study, we identified 82 desaturase gene and protein sequences from 10 grass species deposited in GenBank that were analyzed using bioinformatic approaches. Subcellular localization predictions of desaturase family revealed their localization in plasma membranes, chloroplasts, endoplasmic reticula, and mitochondria. The in silico mapping showed multiple chromosomal locations in most species. Furthermore, the presence of the characteristic histidine domains, the predicted motifs, and the finding of transmembrane regions strongly support the protein functionality. The identification of putative regulatory sites in the promotor and the expression profiles revealed the wide range of pathways in which fatty acid desaturases are involved. This study is an updated survey on desaturases of grasses that provides a comprehensive insight into diversity and evolution. This characterization is a necessary first step before considering these genes as candidates for new biotechnological approaches.     

Effect of different capping agents on physicochemical and antimicrobial properties of ZnO nanoparticles

This research aims to investigate the influence of soluble starch; lactose; carboxymethyl cellulose; urea; and polyvinylpyrrolidone on synthesis of zinc oxide nanoparticles (ZnO-NPs). Zinc acetate was used as a precursor under alkaline conditions to produce ZnO-NPs as a low-cost and efficient antimicrobial and UV-blocking agent. Characterization and antimicrobial functional properties of prepared nanoparticles were investigated and reported using FTIR, TGA, XRD, TEM, analysis, as well as antimicrobial assay, respectively. The results revealed that the thermal decomposition profile, size of ZnO-NPs, IR spectra, as well as antimicrobial activity of the prepared ZnO-NPs is governed by the type of capping agents. Crystallinity analysis showed identical patterns in peak intensities and width irrespective of the used capping agents. On the other hand, the obtained results disclosed that using soluble starch as a capping agent results in attaining lower particle size of 3–5 nm and higher antimicrobial efficacy as compared with the other capping agents.     

High-accuracy determination of water vapor refractivity by length interferometry

Humidity is the most problematic parameter for the accurate determination of the refractive index of air. Besides the fact that the humidity measurement can be limiting, the existing empirical equations for the refractive index of moist air are either restricted to 20 degrees C or are based on insufficient knowledge of the refractivity of water vapor. To overcome this problem, a new kind of measurement method for the refractivity of water vapor is suggested that is based on the accurate measurement of the absolute length of a step length by interferometry under vacuum conditions and subsequent measurements at different well-defined absolute water vapor pressures.     

Properness Defects of Projections and Computation of at Least One Point in Each Connected Component of a Real Algebraic Set

Computing at least one point in each connected component of a real algebraic set is a basic subroutine to decide emptiness of semi-algebraic sets, which is a fundamental algorithmic problem in effective real algebraic geometry. In this article we propose a new algorithm for the former task, which avoids a hypothesis of properness required in many of the previous methods. We show how studying the set of non-properness of a linear projection enables us to detect the connected components of a real algebraic set without critical points for . Our algorithm is based on this observation and its practical counterpoint, using the triangular representation of algebraic varieties. Our experiments show its efficiency on a family of examples.