Dynamics of volumetrically heated matter passing through the liquid-vapor metastable states

Remaining within the pure hydrodynamic approach, we formulate a self-consistent model for simulating the dynamic behavior of matter passing through metastable states in the two-phase liquid-vapor region of the phase diagram. The model is based on the local criterion of explosive boiling, derived by applying the theory of homogeneous bubble nucleation in superheated liquids. Practical application of the proposed model is illustrated with hydrodynamic simulations of a volumetrically uniformly heated planar layer of fused silica SiO2. Implications for experimentally measurable quantities are briefly discussed. A newly developed equation of state, based on the well known QEOS model and capable of handling homogeneous mixtures of elements, was used in the numerical simulations.Comment: 14 pages, 9 figure

Two Scales, One Methodology - Expenditure Based Equivalence Scales for the United States and Germany

Choosing an appropriate equivalence scale is a prerequisite for comparisons of economic wellbeing income distribution, inequality or poverty. This is true for country specific work or for cross-national comparisons. Researchers generally either use a country specific equivalence scale (social assistance, expert based, or poverty scales), or adopt a single scale for all comparison across countries. Here we follow a different approach. We use microdata to estimate equivalence scales based on a revealed preference consumption approach for West Germany and the United States. We review several approaches and rely on a complete demand system approach, which provides constant utility based equivalence scales using an extended linear expenditure system (ELES). The multiple equation expenditure system takes into account a full market basket with all its interdependencies and relative prices. Our consumption-based equivalence results are compared to alternative consumption based measures, expert based measures, and subjective based measures in use in both countries and to other scales used for cross-national comparisons.alternative equivalence scale, Germany, USA, distribution of income, inequality, poverty

Creation of a homogeneous plasma column by means of hohlraum radiation for ion-stopping measurements

In this work, we present the results of two-dimensional radiation-hydrodynamics simulations of a hohlraum target whose outgoing radiation is used to produce a homogeneously ionized carbon plasma for ion-beam stopping measurements. The cylindrical hohlraum with gold walls is heated by a frequency-doubled ($\lambda_l = 526.5$ $\mu m$) $1.4$ $ns$ long laser pulse with the total energy of $E_l = 180$ $J$. At the laser spot, the peak matter and radiation temperatures of, respectively, $T \approx 380$ $eV$ and $T_r \approx 120$ $eV$ are observed. X-rays from the hohlraum heat the attached carbon foam with a mean density of $\rho_C = 2$ $mg/cm^3$ to a temperature of $T \approx 25$ $eV$. The simulation shows that the carbon ionization degree ($Z \approx 3.75$) and its column density stay relatively stable (within variations of about $\pm7\%$) long enough to conduct the ion-stopping measurements. Also, it is found that a special attention should be paid to the shock wave, emerging from the X-ray heated copper support plate, which at later times may significantly distort the carbon column density traversed by the fast ions.Comment: 12 pages, 12 figure

Antimicrobial Activity Of Neem (Azadirachta Indica A. Juss) Leaf Extracts Against Snakehead Fish (Channa Striata) Common Pathogens Aeromonas Hydrophila, Streptococcus Agalactiae, And Staphylococcus Xylosus

The present study describes the potential of neem leaf (Azadirachta indica) extracts to control common bacterial fish pathogens under in-vitro and in-vivo conditions. The first experiment was conducted to assess the antimicrobial activity and minimum inhibitory concentrations of three crude extracts of neem (acetone, methyl alcohol and water), against three common fish pathogens Aeromonas hydrophila, Streptococcus agalactiae and Staphylococcus xylosus. Using well-diffusion methods invitro, the acetone extracts showed activity against all the tested bacteria with zones of inhibition at 13.25, 18.75 and 13.75 mg/ml respectively, while the methyl alcohol and water extracts showed activity only against A. hydrophila. Under in-vitro conditions, minimum inhibitory concentration determinations were conducted using a microdilution method. The acetone and methyl alcohol extracts showed the lowest MIC values, 0.078 and 0.156 mg/ml against S. agalactiae, respectively. A second experiment was conducted to evaluate the biological activities of the three crude extracts, using a brine shrimp (Artemia nauplii) toxicity bioassay. Among the three tested crude extracts, the water extracts showed the lowest toxicity, with LC50 values of 6.41 mg/ml within 24 hours. In the third experiment, the results of qualitative preliminary phytochemical screening of the non-toxic extract showed the presence of Flavonoids and Tannins

Digital entrepreneurship and indigenous value systems: an Ubuntu perspective

This paper investigates the embeddedness of digital entrepreneurship in the entrepreneurs' indigenous value system by examining the influence of ‘Ubuntu’ on digital entrepreneurship activities in the South African context. We do so through an interpretive field study of two innovation clusters in South Africa. Our findings reveal Ubuntu as the basis of a community orientation to digital entrepreneurship that offers an alternative to the prevalent heroic view in which digital entrepreneurship narratives are centred around the individual entrepreneur(s). They also highlight the tensions faced by digital entrepreneurs as they attempt to uphold the Ubuntu values of humility, reciprocity, and benevolence while operating in a competitive and fast-paced environment. In addition, our study indicates that the way entrepreneurs draw on their indigenous value system is dynamic, giving rise to what we call digital Ubuntu, reflecting a reworking of Ubuntu values into their increasingly digital reality. The concept of digital Ubuntu brings to light how indigenous values can become entangled with the capabilities of digital technologies and highlights the need for indigenous perspectives to advance our understanding of the diversity of digital phenomena, such as digital entrepreneurship, across cultural contexts

Probing Reactivity and Substrate Specificity of Both Subunits of the Dimeric \u3ci\u3eMycobacterium tuberculosis\u3c/i\u3e FabH Using alkyl-CoA Disulfide Inhibitors and acyl-CoA Substrates

The dimeric Mycobacterium tuberculosis FabH (mtFabH) catalyses a Claisen-type condensation between an acyl-CoA and malonyl-acyl carrier protein (ACP) to initiate the Type II fatty acid synthase cycle. To analyze the initial covalent acylation of mtFabH with acyl-CoA, we challenged it with mixture of C6-C20 acyl-CoAs and the ESI-MS analysis showed reaction at both subunits and a strict specificity for C12 acyl CoA. Crystallographic and ESI-MS studies of mtFabH with a decyl-CoA disulfide inhibitor revealed a decyl chain bound in acyl-binding channels of both subunits through disulfide linkage to the active site cysteine. These data provide the first unequivocal evidence that both subunits of mtFabH can react with substrates or inhibitor. The discrepancy between the observed C12 acyl-CoA substrate specificity in the initial acylation step and the higher catalytic efficiency of mtFabH for C18-C20 acyl-CoA substrates in the overall mtFabH catalyzed reaction suggests a role for M. tuberculosis ACP as a specificity determinant in this reaction

La Malakoplakie Rétropéritonéale Pseudotumorale

La malakoplakie est une maladie inflammatoire granulomateuse chronique, qui affecte généralement le tractus génito-urinair e et moins fréquemment les autres sites tels que le rétropéritoine et le tractus gastro- intestinal. L’origine infectieuse associée à un déficit dans la digestion macrophagique des bactéries est la théorie physiopathologique la plus soutenue. Sa définition est anatomopathologique. Les auteurs rapportent un cas de malakoplakie rétropéritonéale pseudotumorale chez un patient sous corticothérapie au long cours admis aux urgences pour une masse douloureuse et fébrile du flanc gauche. Les explorations radiologiques étaient en faveur d’une collection abcédée nécessitant un drainage chirurgical en urgence. L’examen histologique des prélèvements réalisés au niveau de la graisse rétropéritonéale révélait une inflammation granulomateuse faite d’histiocytes dénommés cellules de Von Hansemann, renfermant des granulations pathognomoniques de Michaelis-Gutmann. Le patient a été mis sous traitement médical à base de ciprofloxacine avec bonne évolution clinique et radiologique.Mots clés : Malakoplakie; Michaelis-Gutmann; Rétropéritoine