On minimizing dataset transfer time in an acyclic network with four servers

Under consideration is some optimization problem of data transmission in a hierarchical acyclic network. This problem is a special case of the makespan minimization problem with multiprocessor jobs on dedicated machines.We study computational complexity of the subproblems with a specific set of job types, where the type of a job is a subset of the machines required by the job.     

A comparison of electrospray tandem mass spectra of some sialic acid derivatives: Ion trap and high resolution QqToF mass spectrometers

Using O-acetyl-N-acyl derivatives of O-methyl sialoside methyl esters, it was shown that an ion trap and a hybrid analyzer (linear quadrupole–time-of-flight analyzer, reflectron) give comparable, though not identical secondary mass spectra for the [M + Na]⁺ and [M + K]⁺ ions. A parallel use of an ion trap and a hybrid QqToF instrument gives information about the fragmentation pathways of ions of sialic acid derivatives under collisional activation. In this case, the sequence of fragmentation may be established using an ion trap, whereas a QqToF instrument offers a possibility of revealing the elemental composition of fragment ions quickly and unequivocally.     

Syntheses of O-antigen polysaccharide fragments of nitrogen-fixing rhizobacteria of the genus <Emphasis Type="Italic">Azospirillum</Emphasis>

Fragments of O-antigen polysaccharides of nitrogen-fixing rhizobacteria of the genus Azospirillum isolated from natural sources may greatly vary in the monosaccharide composition, molecular weight, as well as in the presence of side chains and branching sites along the main chain. These variations, along with the differences in purity and homogeneity of the samples, hamper investigations of the role of individual components of O-antigen polysaccharides of the rhizobacteria Azospirillum in interactions with plants, including important cereal crops. Therefore, synthetic oligosaccharides, which correspond to O-antigen polysaccharide fragments of rhizobacteria of the genus Azospirillum and have a strictly defined structure and high purity, are highly demanded. The review summarizes the data on the synthesis of these oligosaccharide fragments as promising tools for investigation of the mechanism of formation of a symbiotic association with plants.     

Analysis of lead and sulfur in environmental samples by double pulse laser induced breakdown spectroscopy

In the present work, a model of double pulse laser-induced breakdown spectroscopy (LIBS) spectrometer has been developed and results from two different applications of double pulse LIBS for solving the problems of environmental interest are presented. In one case, laser induced breakdown spectroscopy has been applied to the determination of heavy and toxic metals (lead) in soil samples. In the second case, laser induced breakdown spectroscopy was used in preliminary experiments for the detection of sulfur content in coal, and on the basis of spectral features, ways to improve the sensitivity of laser induced breakdown spectroscopy detection of sulfur are proposed. The detection limit for lead in soil was estimated to be approximately 20 ppm that is lower than the regulatory standards for the presence of lead in soil.     

Development of FARICH detector for particle identification system at accelerators

Aerogel has been successfully used as a radiator in Cherenkov detectors. In 2004, a multilayer aerogel providing Cherenkov ring focusing was proposed and produced. FARICH (Focusing Aerogel Rich Imaging CHerenkov) detectors such as ARICH for Belle-II (KEK, Japan), Forward RICH for PANDA detector (FAIR, Germany), and FARICH for the Super Charm-Tau factory project (BINP, Novosibirsk) have been developed based on this aerogel. Prototypes of FARICH detector based on MRS APD and Philips DPC photosensors were developed and tested in the framework of this project. An angular resolution for Cherenkov rings of 3.6 mrad was achieved.     

Spectra of rubidium-like Pd X-Sn XIV ions

Palladium, silver, and cadmium spectra excited in a low-inductive vacuum spark have been recorded on a vacuum grazing-incidence spectrograph with a grating of 3600 lines/mm and 3 m in radius, in the range 120–350 Å. The 4p ⁶4d-(4p ⁶5p + 4p ⁶4f + 4p ⁵4d ²) transitions in rubidium-like Pd X-Cd XII spectra have been investigated. Twenty two new spectral lines have been identified from the Dirac-Fock and Hartree-Fock calculations and the known lines were measured with high accuracy. The fine-structure intervals for the 4p ⁶4d ² D ground state and the energies of six, seven, and ten energy levels of excited configurations in Pd X, Ag XI, and Cd XII, respectively, were determined. On the basis of the analysis of isoelectronic regularities in the position of the energy levels, the previous identifications for the In XIII and Sn XIV spectra were refined.     

Determination of carbon in soil by laser spectral analysis

We have used a combination laser/electrospark method for fast determination of carbon content in soil. Excitation of the spectra is carried out both directly in a laser ablation plume and when a pulsed electric discharge is applied to it. We have plotted a calibration curve that is linear for the major concentration range of practical importance for the analyte element, all the way up to 8.6%. The carbon detection limit for the combination discharge approach is 0.07%. We have analyzed the ratio of the nitrogen and carbon contents, and also the hydrogen and carbon contents as a function of the carbon concentration in the studied soils samples. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 2, pp. 262–268, March–April, 2008.     

N- and O-carbamoyl and thiocarbamoyl derivatives of B-lactam antibiotics

New N-acylureido and N-acylthioureido derivatives of -lactam antibiotics were obtained by the reaction of 6-ureido and 6-thioureidopenicillanic and 7-thioreidodeacetoxycephalosporanic acids with acyl halides of carboxylic acids and benzoyl isocyanate. 6-Carbamoylhydroxypenicillanic acid, 6-thiocarbamoyl-hydroxypenicillanic acid, and its trichloroethyl ester were obtained by treatment of 6--hydroxypenicillanic acid and its trichloroethyl ester with isocyanatosilanes with subsequent hydrolysis of the N-silylcyanato groups.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 339–342, March, 1985.