Band edges positions prediction of the of Ag nanocluster-decorated titania surfaces and their relationship to NO and NO2 interaction from first-principles calculations.

Metal nanoclusters deposited on oxides have been widely used in photocatalysis playing an important role in the design of model catalysts with applications in heterogeneous catalysis. In particular, we are interested in the potential activity of these cluster-supported systems for the removal of nitrogen oxides either by possible catalytic reduction and/or by their adsorption. In this work, using first-principles methods, we evaluate the main characteristics of Agn (n = 1-4) nanoclusters isolated and deposited on anatase TiO2(101) and rutile TiO2(110) surfaces. Our results indicate that they are preferably adsorbed on rutile surface. The different formation energy at each surface can be explained using a Bader charge analysis. Particularly for Ag4 the lowest formation energy is obtained for tetrahedral geometry while the isolated Ag4 geometry is planar. Small silver deposits placed superficially on titania surfaces modify its electronic structures and improve the conduction band edges positions for possible NO reduction. Band edges positions with respect to the vacuum potential have been studied. The comparison of the conduction band minimum with the reduction potentials of NO/N2O and N2O/N2 shows that they are higher, being Ag3 on rutile and Ag1, Ag2 and Ag4P on anatase better for NO reduction. To complete the analysis, the calculation of work function, energy gap, ionization energy and electron affinity are relevant since they allow the location of semiconductor band edges at point of zero charge. Finally, the adsorption of nitrogen oxides is studied where the NO2 adsorption is favored over NO.

Ants of Mexico: Distribution and species richness in environments with varying levels of human impact.

Background: Anthropogenic disturbance, primarily driven by land-use changes, has caused alterations in ecosystems and biodiversity, including the ant community. Therefore, the aim of this study was to analyse the current landscape of ant species richness and distribution in environments with varying degrees of disturbance in Mexico. Additionally, we sought to identify ant species of ecological, economic and health significance within the country. New information: The present study shows that Mexico has a total of 33,286 records of 1,104 ant species belonging to 10 subfamilies. These species were recorded in a wide variety of environments with different levels of human impact. It was observed that both highly-disturbed environments and undisturbed environments had the highest number of ant records. In undisturbed environments, greater species richness was recorded, with a total of 704 species. Furthermore, the most representative ant species for the country were identified in ecological, economic and human health contexts. Within these species, a group composed of four exotic species (Tapinomamelanocephalum, Paratrechinalongicornis, Wasmanniaauropunctata and Linepithemahumile) deserves special attention, as they have achieved extensive dispersion throughout the country and have been associated with negative impacts in ecological, economic and human health realms.

The Resistance of Seven Host Plants to Tetranychus merganser Boudreaux (Acari: Tetranychidae).

Red spider mites, Tetranychus merganser Boudreaux (Acari: Tetranychidae), is an agricultural pest that causes economic losses in papaya and nopal crops in Mexico. The aim of this research was to assess antibiosis and antixenosis as resistance mechanisms in seven host plants (Thevetia ahouai, Carica papaya, Phaseolus vulgaris, Moringa oleifera, Pittosporum tobira, Helietta parvifolia, Capsicum annuum var. glabriusculum) to red spider mites. Antixenosis was evaluated by non-preference for oviposition and feeding, antibiosis by infinitesimal rate of increase, finite rate of increase and doubling time, and the percentage of spider mites mortality. Oviposition and damage by feeding of T. merganser were significantly greater on C. papaya than on the other host plants. The growth rate of the spider mite was significantly lower in P. tobira and T. ahouai than in the other host plants. The percentage of hatched eggs of T. merganser was significantly higher in P. vulgaris than in the other plant species. Based on the demographic parameters, survival, food intake, and oviposition, these results indicated that compared with C. papaya, P. tobira and T. ahouai were more resistant. These results may be due to the fact that they were plants species of different families. The resistant plants can be studied as alternatives in the management of T. merganser.

Data on A parametric temperature dependent potential for ß-PbF2: A numerical investigation by molecular dynamics.

This article presents the data on a parametric temperature dependent potential for ß-PbF2 using molecular dynamics (MD) simulations in the rigid ion approach. The ß-PbF2 is an important ionic conductor that exhibit a super ionic behavior at 711 K. The understanding of the temperature effect in its properties is crucial for possible applications in electrode for solid state batteries, Cherenkov detectors, and rare earth host for scintillation screen. The simulations were done in the DL_POLY Classic 1.9 package employing the Buckingham pair-potential type. The data have not been reported nor discussed in the research paper to be submitting.

Novel photobioreactor design for the culture of Dunaliella tertiolecta - Impact of color in the growth of microalgae.

Microalgae are affected by the amount of light received. This parameter can be controlled by changing the light source and altering the reactor used for their growth. In this study, the effect of different colors of light was analyzed in the growth of Dunaliella tertiolecta, observing that blue lighting systems reached a biomass 10 times superior to the one generated by orange lightning systems. This growth effect was seen in a novel tubular internally illuminated photobioreactor. In this photobioreactor, the blue reactor produced 1.7 times the biomass of the red reactor, with the particularity that the latter showed an oscillating behavior in its growth. From irradiance models, the light dispersion coefficient is higher than the absorption coefficient when using red light. In contrast, with blue light, the value of the scattering coefficient is almost null.

Regional-Scale Spatio-Temporal Analysis of Anastrepha ludens (Diptera: Tephritidae) Populations in the Citrus Region of Santa Engracia, Tamaulipas, Mexico.

Large citrus areas in Tamaulipas are affected by Anastrepha ludens (Loew) populations. Here we report the findings of a spatio-temporal analysis of A. ludens on an extended citrus area from 2008-2011 aimed at analyzing the probabilities of A. ludens infestation and developing an infestation risk classification for citrus production. A Geographic Information System combined with the indicator kriging geostatistics technique was used to assess A. ludens adult densities in the spring and fall. During the spring, our models predicted higher probabilities of infestation in the western region, close to the Sierra Madre Oriental, than in the east. Although a patchy distribution of probabilities was observed in the fall, there was a trend toward higher probabilities of infestation in the west than east. The final raster models summarized the probability maps using a three-tiered infestation risk classification (low-, medium-, and high risk). These models confirmed the greater infestation risk in the west in both seasons. These risk classification data support arguments for the use of the sterile insect technique and biological control in this extended citrus area and will have practical implications for the area-wide integrated pest management carried out by the National Program Against Fruit Flies in Tamaulipas, Mexico.

Physical and chemical characterization of Pt(12-n)Cu(n) clusters via ab initio calculations.

The physical, structural, and chemical properties of bimetallic Pt(12-n)Cu(n) clusters, where n goes from 0 to 12, have been investigated within density functional theory. We find that the electronic and magnetic properties depend a lot on the atomic fraction of Cu atoms, mainly as the number of Cu atoms changes from even to odd. The chemical potential increases monotonically as a function of the Cu concentration, whereas other chemical properties such as electrophilicity depend on local changes and decreases monotonically, as well as the ionization potential. The hardness has an oscillatory behavior, which depends on the total number of electrons. The reactivity has been spatially analyzed by studying the highest occupied molecular orbital and lowest unoccupied molecular orbital. Charge delocalization is largely increased by the number of copper atoms, whereas for largely Pt concentrations, the charge is more atomiclike. That charge dependence gives another cluster outside view, which shows a rich spatial reactivity. The magnetic dependence of the cluster on the Cu atom concentration opens the door to potential chemistry applications on bimetallic magnetic nanostructures in the field of spintronics.

Diversity driven unbiased search of minimum energy cluster configurations.

The determination of the spatial distributions that atoms adopt to form condensed matter is a problem of crucial importance, since most physical properties depend on the atomic arrangement. This is especially relevant for clusters, where periodicity is nonexistent. Several optimization procedures have been implemented to tackle this problem, with ever increasing success. Here we put forward a search scheme which preserves as large a diversity as allowed by the use of phenomenological potentials, generating in an unbiased fashion a bank of configurations to be explored; a procedure we denominate diversity driven unbiased search (DDUS). It consists in the generation, using phenomenological potentials, of a data bank of putative minima rather than a single, or just a few, configurations which are based on the conformational space annealing method (CSA). All of the configurations in the bank are thereafter refined by means of DFT computations. Certainly, in spite of our efforts to generate a bank as diverse as possible, not all relevant structures might be included in it, since quantum effects are ignored. The procedure is applied to several examples of rhodium, palladium, silver, platinum and gold clusters, between 5 and 23 atoms in size. The main conclusion we reach is that unbiased search, among a significant number of candidates, quite often leads to rather unexpectedly low symmetry configurations, which turn out to be the lowest energy ones within our scheme.

The structure and properties of small Pd clusters.

The zero-temperature minimal energy structure of small free-standing Pd clusters (14≤N≤21, where N is the number of atoms in the cluster), their characteristics and their magnetic configurations are investigated. Results obtained using five different phenomenological many-body potentials (implemented in combination with a genetic algorithm search) are refined by means of various density functional theory (DFT) techniques. The agreement and differences between the results obtained with our procedure, using these five potentials, are displayed in detail. While phenomenological potentials yield values that approach the minimal energies of larger clusters, as compared with DFT results, they fail to predict the right symmetry group for some of the clusters with N>14. We find that the minimal energy configurations are not necessarily associated with high symmetry of the atomic arrangement. Actually, several cases of previously overlooked low symmetry structures turn out to have lower energies than more symmetric ones.

Valoración de la calidad de la atención de enfermería por el cliente / Clients quality valuation of nursing care

La definición de buena calidad de los servicios de salud es difícil y ha sido objeto de muchos acercamientos. Se realizó un estudio descriptivo, observacional, retrospectivo con la finalidad de determinar la calidad asistencial percibida por los pacientes ingresados en el CRP (Centro de Retinosis Pigmentaria) ubicado en Bayamo, Cuba, durante el año 2005. Utilizamos un cuestionario, que se utiliza en la evaluación del desempeño profesional de las enfermeras, que incluye criterios relacionados con el individuo, la recepción de enfermería durante el ingreso, la atención de enfermería durante el cambio de turno, y criterios relacionados con la satisfacción y la calidad de la atención de enfermería recibida durante el ingreso. La variable dependiente fue la satisfacción del usuario por la atención recibida, definida como la percepción del entrevistado sobre la atención que recibió, y la evaluación de la calidad al sumar la puntuación de todos los ítems. Para estimar la diferencia entre grupos se utilizó el ANOVA no paramétrico para muestras independientes y variable dependiente ordinal de Kruskall-Wallis La evaluación se consideró aceptable cuando las respuestas arrojaron puntuaciones entre los 124 a 155 puntos se entendieron como buena, muy buena y excelente según la escala Liker utilizada, y las respuestas con puntuaciones entre los 31 a 93 puntos se corresponden con niveles de insatisfacción. Los entrevistados evaluaron de forma muy positiva la calidad del servicio recibido, sólo que para algunos resultó de excelente calidad, para otros de muy buena, y para el resto de mediana calidad, donde el 75 por ciento de los entrevistados obtuvieron puntuaciones superiores a los 124 puntos. Las altas valoraciones encontradas ratifica la necesidad de proveer servicios de salud de alta calidad y de esta forma lograr un impacto positivo en la salud de la población(AU)

The definition of a good quality in Health Services is difficult and it has been object of several approaches. It was carried out a descriptive, observational, retrospective study with the objective to determine the assistance quality perceived by hospitalized patients in PRC located in Bayamo, Cuba during 2005. Survey was applied to evaluate the professional fulfilment of nurses that includes different criteria related with the individual, nursing reception during the hospitalization, nursing care during the shift change and related criterion with nursing care satisfaction due to the received care and the quality evaluation at the time of adding the punctuation of all the items. To estimate the difference among groups it was used the non-parametric ANOVA for independent samples and Kruskall-wallis ordinal dependent variables. The evaluation was considered acceptable when the answers showed punctuations of 124 to 155 points and they were accepted as good, very good and excellent, according to LIKER scale, and answers with punctuations of 31-93 points corresponded to non satisfactory level. The interviewed persons evaluated the quality of the service as positive; for some of them it was of excellent quality for some others it was good and for the rest it was of average quality where the 75 per cent of the interviewed persons obtained higher punctuations of 124 points. The highly found valuations confirmed the need to provide Health Services of great quality and through this way get a positive impact in population health(EU)

Alternative search strategy for minimal energy nanocluster structures: the case of rhodium, palladium, and silver.

An alternative strategy to find the minimal energy structure of nanoclusters is presented and implemented. We use it to determine the structure of metallic clusters. It consists in an unbiased search, with a global minimum algorithm: conformational space annealing. First, we find the minima of a many-body phenomenological potential to create a data bank of putative minima. This procedure assures us the generation of a set of cluster configurations of large diversity. Next, the clusters in this data bank are relaxed by ab initio techniques to obtain their energies and geometrical structures. The scheme is successfully applied to magic number 13 atom clusters of rhodium, palladium, and silver. We obtained minimal energy cluster structures not previously reported, which are different from the phenomenological minima. Moreover, they are not always highly symmetric, thus casting some doubt on the customary biased search scheme, which consists in relaxing with density functional theory global minima chosen among high symmetry structures obtained by means of phenomenological potentials.

Anomalías cromosómicas clonales en tumores colorectales / Clonal chromosomal abnormalities in colorectal tumors

Los tumores colorectales constituyen un motivo de consulta frecuente en los servicios de gastroenterología a nivel mundial, representando la segunda causa de muerte en el mundo y la cuarta causa de mortalidad por cáncer en Venezuela. Usualmente comienza como un pólipo benigno que en muchas ocasiones se transforma en maligno debido a una mutación a nivel del código genético que controla el crecimiento y la reparación celular. El presente trabajo reporta las alteraciones cromosómicas observadas en 15 muestras de tumores colorectales benignos y malignos estudiados en la Unidad Genética médica de la Universidad del Zulia. Se encontraron anomalías cromosómicas clonales en 11/15 (73,33 por ciento), 4 correspondieron a carcinomas y 7 a pólipos adenomatosos, en 7/11 (63,6 por ciento) se encontraron anomalías tipo monosomía de los cromosomas 8 y 22, otras anomalías correspondieron a trisomías de los cromosomas 11 y 18 y uno solo de los casos con una anomalía estructural que correspondió a una del (17p). Las anomalías cromosómicas clonales en pólipos adenomatosos han sido relacionadas con inicio de la enfermedad maligna, y en el caso de los carcinomas, se ha relacionado con progresión de la enfermedad hacia la metástasis y muerte, por lo que la utilización del análisis citogenética podría establecerse como un facrtor pronóstico para los pacientes con poliposis adenomatosa no familiar

Morbilidad en consulta externa de urología / s. t

Se realizó un estudio prospectivo, longitudinal y descriptivo para conocer el comportamiento de la morbilidad de las principales afecciones urológicas en la consulta externa del Servicio de Urología del Hospital Provincial General Docente Carlos Manuel de Céspedes. Se estudiaron 120 pacientes en el período comprendido entre el 1ro de enero y el 31 de diciembre de 1998. El adenoma prostático predominó en la serie (37,1 por ciento). La edad media de los pacientes fue de 51,25 años (±19,52), y predominó el grupo de 30 a 44 años (30,9 por ciento). El sexo masculino dominó en la serie (90,8 por ciento). Predominó la concordancia diagnóstica negativa entre los diferentes grupos de remitentes (55,8 por ciento). El examen físico fue el método diagnóstico principal (54,7 por ciento). Las afecciones urológicas halladas en la investigación son fácilmente diagnosticables por examen físico, lo cual puede ser realizado por un médico general con entrenamiento mínimo(AU)

Morbilidad en Consulta externa de urología / Morbidity in the Urology Outpatient Department

Se realizó un estudio prospectivo, longitudinal y descriptivo para conocer el comportamiento de la morbilidad de las principales afecciones urológicas en la consulta externa del Servicio de Urología del Hospital Provincial General Docente Carlos Manuel de Céspedes. Se estudiaron 120 pacientes en el período comprendido entre el 1ro. de enero y el 31 de diciembre de 1998. El adenoma prostático predominó en la serie (37,1 porciento). La edad media de los pacientes fue de 51,25 años (ñ19,52), y predominó el grupo de 30 a 44 años (30,9 porciento). El sexo masculino dominó en la serie (90,8 porciento). Predominó la concordancia diagnóstica negativa entre los diferentes grupos de remitentes (55,8 porciento). El examen físico fue el método diagnóstico principal (54,7 porciento). Las afecciones urológicas halladas en la investigación son fácilmente diagnosticables por examen físico, lo cual puede ser realizado por un médico general con entrenamiento mínimo(AU)

A prospective, longitudinal and descriptive study was conducted to know the behavior of morbidity of the main urologic affections at the Outpatient Department of the Urology Service of Carlos Manuel de Céspedes Provincial General Teaching Hospital. 120 patients were studied from January 1st to December 31st, 1998. The prostatic adenoma predominated in the series (37.1 percent). The average age of the patients was 51.25 percent ( ± 19.52). The age group 30-44 (30.9 percent) prevailed. Most of the patients were males (90.8 percent). The negative diagnostic concordance predominated among the different groups of referred patients (55.8 percent). The physical examination was the main diagnostic method (54.7 percent). The urologic affections found in our investigation may be easily diagnosed by physical examination, which can be made by a general physician with a minimum training(AU)

[Clonal chromosomal anomalies in colorectal tumors]. / Anomalías cromosómicas clonales en tumores colorectales.

Colorectal tumors constitute a reason of frequent consultation in gastroenterology services in the world. They constitute the second cause of mortality in the world and the fourth cause of mortality for cancer in Venezuela. It usually begins as a polyp that becomes malignant due to a mutation at the level of the genetic code that controls the growth and the repair of cells. The present work reports the clonal chromosomal abnormalities observed in 15 samples from benign tumors as well as malignant colorectal tumors and to relate these findings. There were clonal chromosomal anomalies in 11/15 (73.33%), 4 corresponded to carcinomas and 7 to adenomatous polyps. In 7/11 (63.6%) there were anomalies of the monosomy type in the chromosomes 8 and 22, other anomalies corresponded to trisomy of the chromosomes 11 and 18, and a single case with a structural anomaly that corresponded to a del(17p). The chromosomal anomalies in adenomatous polyposis have been related with the beginning of malignant disease and, in the case of carcinomas, it has been related with progression of the illness toward metastasis and death. The use of this tool could be used as a prognostic factor for patients with non familial adenomatous polyposis.

Comportamiento de la cirugía urológica ambulatoria infantil 1997

Se realizó un estudio observacional, descriptivo y prospectivo de la cirugía urológica mayor ambulatoria en niños durante el año 1997 en el hospital general docente Carlos Manuel de Céspedes de Bayamo, que incluyó a 119 pacientes intervenidos quirúrgicamente utilizando este método. La entidad nosológica predominante fue la fímosis con 30,2 por ciento, el grupo de edad más afectado fue el de 1 a 5 años (46 pacientes). El sexo masculino superó al femenino con 116 pacientes. Las complicaciones trans- y postoperatorias principales fueron: el desgarro del conducto peritoneo-vaginal (50 por ciento) y somnolencia (33,3 por ciento);98.3 por ciento de los familiares se mostraron satisfechos con éste método quirúrgico. Por concepto día paciente seprodujo un ahorro significativo para la institución de $ 13 308,96.(AU)