An estimation of distribution algorithm for combinatorial optimization problems

This paper considers solving more than one combinatorial problem considered some of the most difficult to solve in the combinatorial optimization field, such as the job shop scheduling problem (JSSP), the vehicle routing problem with time windows (VRPTW), and the quay crane scheduling problem (QCSP). A hybrid metaheuristic algorithm that integrates the Mallows model and the Moth-flame algorithm solves these problems. Through an exponential function, the Mallows model emulates the solution space distribution for the problems; meanwhile, the Moth-flame algorithm is in charge of determining how to produce the offspring by a geometric function that helps identify the new solutions. The proposed metaheuristic, called HEDAMMF (Hybrid Estimation of Distribution Algorithm with Mallows model and Moth-Flame algorithm), improves the performance of recent algorithms. Although knowing the algebra of permutations is required to understand the proposed metaheuristic, utilizing the HEDAMMF is justified because certain problems are fixed differently under different circumstances. These problems do not share the same objective function (fitness) and/or the same constraints. Therefore, it is not possible to use a single model problem. The aforementioned approach is able to outperform recent algorithms under different metrics for these three combinatorial problems. Finally, it is possible to conclude that the hybrid metaheuristics have a better performance, or equal in effectiveness than recent algorithms

Calcium/calmodulin kinase1 and its relation to thermotolerance and HSP90 in Sporothrix schenckii: an RNAi and yeast two-hybrid study

<p>Abstract</p> <p>Background</p> <p><it>Sporothrix schenckii </it>is a pathogenic dimorphic fungus of worldwide distribution. It grows in the saprophytic form with hyaline, regularly septated hyphae and pyriform conidia at 25°C and as the yeast or parasitic form at 35°C. Previously, we characterized a calcium/calmodulin kinase in this fungus. Inhibitors of this kinase were observed to inhibit the yeast cell cycle in <it>S. schenckii</it>.</p> <p>Results</p> <p>The presence of RNA interference (RNAi) mechanism in this fungus was confirmed by the identification of a Dicer-1 homologue in <it>S. schenckii </it>DNA. RNAi technology was used to corroborate the role of calcium/calmodulin kinase I in <it>S. schenckii </it>dimorphism. Yeast cells were transformed with the pSilent-Dual2G (pSD2G) plasmid w/wo inserts of the coding region of the calcium/calmodulin kinase I (<it>sscmk1</it>) gene. Transformants were selected at 35°C using resistance to geneticin. Following transfer to liquid medium at 35°C, RNAi transformants developed as abnormal mycelium clumps and not as yeast cells as would be expected. The level of <it>sscmk1 </it>gene expression in RNAi transformants at 35°C was less than that of cells transformed with the empty pSD2G at this same temperature. Yeast two-hybrid analysis of proteins that interact with SSCMK1 identified a homologue of heat shock protein 90 (HSP90) as interacting with this kinase. Growth of the fungus similar to that of the RNAi transformants was observed in medium with geldanamycin (GdA, 10 μM), an inhibitor of HSP90.</p> <p>Conclusions</p> <p>Using the RNAi technology we silenced the expression of <it>sscmk1 </it>gene in this fungus. RNAi transformants were unable to grow as yeast cells at 35°C showing decreased tolerance to this temperature. The interaction of SSCMK1 with HSP90, observed using the yeast two-hybrid assay suggests that this kinase is involved in thermotolerance through its interaction with HSP90. SSCMK1 interacted with the C terminal domain of HSP90 where effector proteins and co-chaperones interact. These results confirmed SSCMK1 as an important enzyme involved in the dimorphism of <it>S. schenckii</it>, necessary for the development of the yeast phase of this fungus. Also this study constitutes the first report of the transformation of <it>S. schenckii </it>and the use of RNAi to study gene function in this fungus.</p

Analysis of the influence of the plasma thermodynamic regime in the spectrally resolved and mean radiative opacity calculations of carbon plasmas in a wide range of density and temperature

In this work the spectrally resolved, multigroup and mean radiative opacities of carbon plasmas are calculated for a wide range of plasma conditions which cover situations where corona, local thermodynamic and non-local thermodynamic equilibrium regimes are found. An analysis of the influence of the thermodynamic regime on these magnitudes is also carried out by means of comparisons of the results obtained from collisional-radiative, corona or Saha–Boltzmann equations. All the calculations presented in this work were performed using ABAKO/RAPCAL code

Determination and analysis of plasma radiative properties for numerical simulations of laboratory radiative blast waves launched in xenon clusters

Radiative shock waves play a pivotal role in the transport energy into the stellar medium. This fact has led to many efforts to scale the astrophysical phenomena to accessible laboratory conditions and their study has been highlighted as an area requiring further experimental investigations. Low density material with high atomic mass is suitable to achieve radiative regime, and, therefore, low density xenon plasmas are commonly used for the medium in which the radiative shocks propagate. The knowledge of the plasma radiative properties is crucial for the correct understanding and for the hydrodynamic simulations of radiative shocks. In this work, we perform an analysis of the radiative properties of xenon plasmas in a range of matter densities and electron temperatures typically found in laboratory experiments of radiative shocks launched in xenon plasmas. Furthermore, for a particular experiment, our analysis is applied to make a diagnostics of the electron temperatures of the radiative shocks since they could not be experimentally measure

Relativistic screened hydrogenic radial integrals

The computation of dipole matrix elements plays an important role in the study of absorption or emission of radiation by atoms in several fields such as astrophysics or inertial confinement fusion. In this work we obtain closed formulas for the dipole matrix elements of multielectron ions suitable for using in the framework of a Relativistic Screened Hydrogenic Model

Tele-care and tele-alarms for the elderly: preliminary experiences in Mexico

OBJETIVO Analizar el efecto de un programa piloto de tele-asistencia y tele-alarma en la autopercepción del estado de salud de los adultos mayores y conocer la satisfacción y aceptación del programa. METODOS Estudio transversal que incluyó entrevistas a 378 adultos mayores, 294 cuidadores/familiares y 53 profesionales de la salud, realizado en la Ciudad de México en 2010. Variables sociodemográficas, de autopercepción del estado de salud, satisfacción y aceptación del programa se obtuvieron por medio de cuestionario estandarizado. Se realizó análisis descriptivo y se utilizaron pruebas no paramétricas. RESULTADOS Se observaron efectos significativos en la autopercepción del estado de salud, 6,17 (DE 17,9 p < 0,05) puntos por encima de la media. El programa tuvo una buena aceptación por parte de los adultos mayores, de sus cuidadores familiares y de los profesionales de la salud. CONCLUSIONES El programa contribuye a mantener o mejorar la calidad de vida, permite la atención preventiva y es un medio ideal para dar apoyo psicosocial a los adultos mayores.OBJECTIVE : To analyze the effect of a pilot program of tele-assistance and tele-alarms on the elderly’s self-perception of health status and to identify the satisfaction with and acceptance of the program. METHODS : Cross-sectional study that included interviews with 378 elderly individuals, 294 caretakers/relatives and 53 health care professionals. The program was run in Mexico City in 2010. The variables were socio-demographic characteristics, self-rated health, satisfaction and acceptance of the program. The information was gathered through a standardized questionnaire. The statistical analysis included descriptive analysis and nonparametric tests. RESULTS : Significant effects on self-perception of health were observed, 6.17 (SD 17.9 p < 0.05) points above the average. The program was well received and accepted by the elderly, family caregivers and health professionals. CONCLUSIONS : The program helps to maintain or improve quality of life, allows preventive care and is an ideal means of providing psychosocial support to the elderly

Parametrization of the average ionization and radiative cooling rates of carbon plasmas in a wide range of density and temperature

In this work we present an analysis of the influence of the thermodynamic regime on the monochromatic emissivity, the radiative power loss and the radiative cooling rate for optically thin carbon plasmas over a wide range of electron temperature and density assuming steady state situations. Furthermore, we propose analytical expressions depending on the electron density and temperature for the average ionization and cooling rate based on polynomial fittings which are valid for the whole range of plasma conditions considered in this work