Negative ion spectrometry for detecting nitrated explosives

Ionization procedure is modified to produce mainly negative ions by electron capture. Peaks of negative ions are monitored conventionally. Nitrated organic materials could be identified directly from sample sniff inlet stream by suitably modified mass spectrometer because of unique electronegativity which nitro group imparts to organic material

Tuberculosis vaccine strain _Mycobacterium bovis_ BCG Russia is a natural _recA_ mutant

The current tuberculosis vaccine is a live vaccine derived from _Mycobacterium bovis_ and attenuated by serial _in vitro_ passaging. All vaccine substrains in use stem from one source, strain Bacille Calmette-Guérin. However, they differ in regions of genomic deletions, antigen expression levels, immunogenicity, and protective efficacy. As a RecA phenotype increases genetic stability and may contribute restricting the ongoing evolution of the various BCG substrains, we aimed to inactivate _recA_ by allelic replacement in BCG vaccine strains representing different phylogenetic lineages (Pasteur, Frappier, Denmark, Russia). Homologous gene replacement was successful in three out of four strains. However, only illegitimate recombination was observed in BCG substrain Russia. Sequence analyses of _recA_ revealed that a single nucleotide insertion in the 5' part of _recA_ led to a translational frameshift with an early stop codon making BCG Russia a natural _recA_ mutant. At the protein level BCG Russia failed to express RecA. According to phylogenetic analyses BCG Russia is an ancient vaccine strain most closely related to the parental _M. bovis_. Our data suggest that _recA_ inactivation in BCG Russia occurred early and is in part responsible for its high degree of genomic stability, resulting in a substrain that has less genetic alterations than other vaccine substrains with respect to _M. bovis_ AF2122/97 wild type

Sample processor for chemical analysis

An apparatus is provided which can process numerous samples that must be chemically analyzed by the application of fluids such as liquid reagents, solvents and purge gases, as well as the application of dumps for receiving the applied fluid after they pass across the sample, in a manner that permits numerous samples to be processed in a relatively short time and with minimal manpower. The processor includes a rotor which can hold numerous cartridges containing inert or adsorbent material for holding samples, and a pair of stators on opposite sides of the rotor. The stators form stations spaced along the path of the cartridges which lie in the rotor, and each station can include an aperture in one stator through which a fluid can be applied to a cartridge resting at that station, and an aperture in the other stator which can receive the fluid which has passed through the cartridge. The stators are sealed to the ends of the cartridges lying on the rotor, to thereby isolate the stations from one another

Automated mass spectrometer/analysis system: A concept

System performs rapid multiple analyses of entire compound classes or individual compounds on small amounts of sample and reagent. Method will allow screening of large populations for metabolic disorders and establishment of effective-but-safe levels of therapeutic drugs in body fluids and tissues

Electronic Stopping and Momentum Density of Diamond Obtained from First-Principles Calculations

We calculate the "head" element or the (0,0)-element of the wave-vector and frequency-dependent dielectric matrix of bulk crystals via first-principles, all-electron Kohn-Sham states in the integral of the irreducible polarizability in the random phase approximation. We approximate the macroscopic "head" element of the inverse matrix by its reciprocal value, and integrate over frequencies and momenta to obtain the electronic energy loss of protons at low velocities. Numerical evaluation for diamond targets predicts that the band gap causes a strong non-linear reduction of the electronic stopping power at ion velocities below 0.2 atomic units.Comment: 8 pages, 6 figures, REVTeX

Educación para la Defensa, una herramienta estratégica para la cooperación regional Suramericana

En noviembre de 2012, los Ministros/as del Consejo Suramericano de Defensa (CDS) decidieron la conformación de un Grupo de Trabajo con la misión de elaborar una propuesta para la creación de la Escuela Suramericana de Defensa (ESUDE). Durante el año 2013, se reunieron en primer lugar los países responsables, Argentina, Brasil y Ecuador; a quienes se sumaron luego los demás miembros del CDS a las reuniones. El proceso acabó en un documento que fue aprobado en febrero de 2014, en Paramaribo. Así, conformada como un centro de enseñanza superior que busca coordinar las iniciativas nacionales, ESUDE representa un espacio institucional dedicado a la formación de civiles y militares en temas de Defensa y Seguridad regional en el nivel político-estratégico. En este contexto, el trabajo, de naturaleza exploratoria, está estructurado en cuatro ejes. En primer lugar, presenta la perspectiva teórica desde la cual aborda la problemática. En segundo lugar, considera a la educación como una dimensión sustantiva para el proceso de cooperación regional en términos de construcción de identidad. En tercer lugar, destaca su relevancia particular en el campo de la defensa y explora su relación con el desarrollo de un pensamiento estratégico propio como base para un proyecto de América del Sur. En cuarto lugar, reseña la breve trayectoria de la ESUDE y discute sus potencialidades y desafíosFil: Da Ponte, Aureliano. ESG/USAL/EDENA/INEST-UFF.Fil: Boettger, Constanza. USAL/ESG

On the Convergence of the Electronic Structure Properties of the FCC Americium (001) Surface

Electronic and magnetic properties of the fcc Americium (001) surface have been investigated via full-potential all-electron density-functional electronic structure calculations at both scalar and fully relativistic levels. Effects of various theoretical approximations on the fcc Am (001) surface properties have been thoroughly examined. The ground state of fcc Am (001) surface is found to be anti-ferromagnetic with spin-orbit coupling included (AFM-SO). At the ground state, the magnetic moment of fcc Am (001) surface is predicted to be zero. Our current study predicts the semi-infinite surface energy and the work function for fcc Am (001) surface at the ground state to be approximately 0.82 J/m2 and 2.93 eV respectively. In addition, the quantum size effects of surface energy and work function on the fcc Am (001) surface have been examined up to 7 layers at various theoretical levels. Results indicate that a three layer film surface model may be sufficient for future atomic and molecular adsorption studies on the fcc Am (001) surface, if the primary quantity of interest is the chemisorption energy.Comment: 34 pages, 9 figure

High-pressure Debye-Waller and Grueneisen parameters of Au and Cu

The lattice vibrations are determined in the quasi-harmonic approximation for elemental Au and Cu to twice their normal density by first-principles electronic band-structure calculations. It is found for these materials that the important moments of the phonon density of states can be obtained to high accuracy from short-ranged force constant models. We discuss the implications for the Grueneisen parameters on the basis of calculated phonon moments and their approximations by using bulk moduli and Debye-Waller factors.Comment: 4 pages, 2 figures to appear in the proceedings of the 13th APS Topical Conference on Shock Compression of Condensed Matter (scheduled for April 2004

A Concepção Histórico-Social da Relação entre a Realidade e a Produção do Conhecimento Matemático

Este artigo apresenta algumas considerações relativas ao processo histórico-social de desenvolvimento da matemática. Trata-se de um trecho da tese de doutoramento do autor (GIARDINETTO,1997). A referida tese sofreu alterações e foi publicada em 1999 pela Editora Autores Associados2 (GIARDINETTO,1999). O trecho da tese (com pequenas adaptações) apresentado neste artigo não está presente no livro publicado