Fine-tuning the degree of organic functionalization of mesoporous silica nanosphere materials via an interfacially designed co-condensation method

A synthetic method that can fine tune the amount of chemically accessible organic functional groups on the pore surface of MCM-41 type mesoporous silica nanosphere (MSN) materials has been developed by electrostatically matching various anionic organoalkoxysilanes with the cationic cetyltrimethylammonium bromide micelles in a base-catalyzed condensation reaction of tetraethoxysilane.     

Evidence for B+ --> K0K+ and B0 --> K0K0, and measurement of the branching fraction and search for direct CP violation in B+ --> K0pi+

We present evidence for the b --> d penguin-dominated decays B+ --> K0K+ and B0 --> K0K0 in 227 x 10(6) Y(4S) --> BB decays collected with the BABAR detector. We measure the branching fractions B(B+ --> K0K+) = (1.5 +/- 0.5 +/- 0.1) x 10(-6)(< 2.4 x 10(-6)) and B(B0 --> K0K0) = [formula: see text], where the uncertainties are statistical and systematic, respectively. We also present improved measurements of the charge-averaged branching fraction B(B+ --> K0pi+) = (26.0 +/- 1.3 +/- 1.0) x 10(-6) and CP-violating charge asymmetry A(CP) (K0pi+) = -0.09 +/- 0.05 +/- 0.01), where the uncertainties are statistical and systematic, respectively.     

Search for strange-pentaquark production in e+e- annihilation at sqrt[s] = 10.58 GeV

We search for strange-pentaquark states that have been previously reported by other experiments--the Theta (1540)(+), Xi(5)(1860)(--), and Xi(5)(1860)(0)--in 123 fb(-1) of data recorded with the BABAR detector at the PEP-II e(+)e(-) storage ring. We find no evidence for these states and set 95% confidence level upper limits on the number of Theta(1540)(+) and Xi(5)(1860)(--) pentaquarks produced per e(+)e(-) annihilation into qq and Gamma(4S) decay. For qq events the Theta(1540)(+) [Xi(5)(1860)(--)] limit is about 8 [4] times lower than the rates measured for ordinary baryons of similar mass.     

Branching fractions and CP asymmetries in B0-->pi0pi0, B+-->pi+pi0, and B+-->K+pi0 decays and isospin analysis of the B-->pipi system

Based on a sample of 227 x 10(6) BB pairs collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC, we measure the branching fraction B(B0-->pi(0)pi(0))=(1.17+/-0.32+/-0.10)x10(-6), and the asymmetry Cpi(0)(pi(0))=-0.12+/-0.56+/-0.06. The B0-->pi(0)pi(0) signal has a significance of 5.0 sigma. We also measure B(B+-->pi(+)pi(0))=(5.8+/-0.6+/-0.4)x10(-6), B(B+-->K+pi(0))=(12.0+/-0.7+/-0.6)x10(-6), and the charge asymmetries Api(+)(pi(0))=-0.01+/-0.10+/-0.02 and AK+(pi(0))=0.06+/-0.06+/-0.01. Using isospin relations, we find an upper bound on the angle difference |alpha-alpha(eff)| of 35 degrees at the 90% C.L.     

An optimization model for combined selecting,planting and harvesting sugarcane varieties

The problem of selecting sugarcane varieties has been widely discussed due to its computational complexity and its great impact for the sugar and ethanol industry. This paper proposes a new integrated mathematical programming model to deal with the selection of sugarcane varieties to be planted and the determination of the optimal period for planting and harvesting in order to increase production in the sugarcane industry. The proposed model optimizes the production of sugarcane and improves the quality of biomass whilst satisfying the main constraints imposed by sugarcane companies. The problem is modelled as an integer linear program and solved using an exact method to generate optimal solutions for small and medium problems. For large problems, metaheuristic approaches based on Genetic Algorithm and Variable Neighbourhood Search are proposed. According to the results, the proposed methodology provides sugarcane company managers with decision support in selecting the most suitable varieties and in determining the best period to plant and harvest their sugarcane.

     

A load balancing system in the many-server heavy-traffic asymptotics

Queueing Systems - We study a load balancing system in the many-server heavy-traffic regime. We consider a system with N servers, where jobs arrive to the system according to a Poisson process and...     

Voltammetric determination of thiodiglycolic acid in urine

In urine the level of thiodiglycolic acid (TDGA) is a sensitive indicator of exposure of the human organism to some physiologically active or toxic substances, gases and vapors. The determination of TDGA by use of a voltammetric method based on electroreduction of TDGA in acidic solution at the hanging mercury drop electrode has been developed and practically tested. In order to eliminate the matrix effect of urine, prior to voltammetric measurement the samples are eluted from a small column of PVC powder. The method is simple, low cost, rapid and sensitive, appropriate for the needs of occupational medicine.