Synthesis and Electrical Characterization of PLZT Piezoelectric-Ceramic

This research describes the synthesis of an outstanding ceramic-composite piezoelectric CCP (lead-lanthanum-zirconate-titanate, PLZT) by means of powders technique procedures. Full dense CCP compacts were obtained with a platinum wire implanted in the center of the piezoelectric, which were used to investigate the microstructural and opto-thermal properties. The microstructural details of this ceramic were investigated by optical microscopy; whereas the opto-thermal characterization was performed by measuring the electrical signal in a bidimensional setup under four different temperatures: 20°C, 35°C, 50°C and 75°C. A 160mW/cm2 LASER beam was used in order to produce the optical energy which is detected by the CCP. A total of one hundred of measurements were registered. Measurements showed that, in the explored thermal range, the CCP signal magnitude increased from 87.2 to 147.2 pA. About the microstructural analysis, the microstructure obtained show different phases as characteristic of the processing method, including porosity. The peculiar optical and thermal properties observed in the piezoelectric ceramic are promising for possible applications in temperature-controlled optical devices that require electrical outputs

Ertapenem susceptibility of extended spectrum beta-lactamase-producing organisms

<p>Abstract</p> <p>Background</p> <p>Infections caused by multiply drug resistant organisms such as extended spectrum <it>beta</it>-lactamase (ESBL)-producing <it>Escherichia coli </it>and <it>Klebsiella pneumoniae </it>are increasing. Carbapenems (imipenem and meropenem) are the antibiotics commonly used to treat these agents. There is limited clinical data regarding the efficacy of the newest carbapenem, ertapenem, against these organisms. Ertapenem susceptibility of ESBL-producing <it>E. coli </it>and <it>K. pneumoniae </it>clinical isolates were evaluated and compared to imipenem to determine if imipenem susceptibility could be used as a surrogate for ertapenem susceptibility.</p> <p>Methods</p> <p>100 ESBL isolates (n = 34 <it>E. coli </it>and n = 66 <it>K. pneumoniae</it>) collected from 2005–2006 clinical specimens at WRAMC were identified and tested for susceptibility by Vitek Legacy [bioMerieux, Durham, NC]. Ertapenem susceptibility was performed via epsilometer test (E-test) [AB Biodisk, Solna, Sweden].</p> <p>Results</p> <p>100% of ESBL isolates tested were susceptible to ertapenem. 100% of the same isolates were also susceptible to imipenem.</p> <p>Conclusion</p> <p>These results, based on 100% susceptibility, suggest that ertapenem may be an alternative to other carbapenems for the treatment of infections caused by ESBL-producing <it>E. coli </it>and <it>K. pneumoniae</it>. Clinical outcomes studies are needed to determine if ertapenem is effective for the treatment of infection caused by these organisms. However, due to lack of resistant isolates, we are unable to conclude whether imipenem susceptibility accurately predicts ertapenem susceptibility.</p

Incidencia de la Responsabilidad Social Empresarial como Ventaja Competitiva en el Sector Inmobiliario de la Ciudad de Tacna.

La Responsabilidad Social Empresarial (RSE), apareció en un escenario de proceso de globalización que ocasionó cambios económicos a nivel mundial. Por lo cual; frente a esta perspectiva apareció la necesidad de incorporar nuevos enfoques conceptuales en negocios, para responder a tales tendencias se introdujo nuevas reglas, donde se ven inmersos la comunidad y/o sociedad, representando una Ventaja Competitiva frente a Empresas que operan en el sector. El presente trabajo de Investigación “INCIDENCIA DE LA RESPONSABILIDAD SOCIAL EMPRESARIAL COMO UNA VENTAJA COMPETITIVA EN EL SECTOR INMOBILIARIO DE LA CIUDAD DE TACNA” está direccionado al análisis de la RSE, inmerso dentro de las políticas de Gestión Empresarial en cada organización, con el objetivo principal de determinar si la RSE en el Sector Inmobiliario genera una ventaja competitiva en el consumidor; para que pueda ser usado frente a otras Organizaciones, y obtener una mejora estrictamente Económica, Social y Ambiental en un entorno Social y Natural. La Investigación tiene como característica, ser de tipo aplicada ya que busca solucionar problemas prácticos relacionados a la RSE, con nivel correlacional porque medirá la relación para cada variable, y ubicada dentro de un diseño no experimental – transversal ya que no se manipulan las variables en estudio y la recolección de los datos se dará en un tiempo y espacio único.Tesi

Nuevos registros del camarón tigre Penaeus monodon Fabricius, 1798 (Decapoda: Penaeidae) en el Sistema del Lago de Maracaibo, Venezuela [New records of Giant Tiger Prawn, Penaeus monodon Fabricius, 1798 (Decapoda: Panaeidae) in the Maracaibo Lake System, Venezuela]

The Asian tiger shrimp, Penaeus monodon (Decapoda: Penaidae), is an Asian species considered as alien in the Atlantic Ocean waters. This paper confirms the presence of P. monodon along the coasts of the Maracaibo Lake System. We evaluated multiple artisanal ports in the following localities: Castilletes, Porshoure, Kazuzain, Caño Sagua, Zapara Island, and Santa Rosa de Agua. We collected five adult individuals from Castilletes, Zapara Island, and Santa Rosa de Agua, the specimens were deposited in the Museum of Biology of the University of Zulia (Experimental Faculty of Sciences), within the section of aquatic invertebrates under the following museum catalogue numbers: MBLUZ-2503, MBLUZ-2515, MBLUZ-2516, and MBLUZ2517. These records confirmed the presence of P. monodon along the four aquatic environments that form the Maracaibo Lake System (Gulf of Venezuela, El Tablazo Bay, Maracaibo Strait, and Maracaibo Lake), indicating a possible increase in the species’ populations across region. Future researches must be focused to evaluate the population status of P. monodon in the Maracaibo Lake System, as well as for the design of effective strategies for the effective management of this resource. El camarón tigre, Penaeus monodon (Decapoda: Penaeidae), es una especie asiática considerada como exótica en el Océano Atlántico. En este trabajo se confirma la presencia de P. monodon a lo largo de las costas del Sistema del Lago de Maracaibo. Fueron evaluados los puertos pesqueros artesanales de las localidades de Castilletes, Porshoure, Kazuzain, Caño Sagua, Isla Zapara y Santa Rosa de Agua. Se capturaron cinco ejemplares adultos provenientes de las localidades de Castilletes, Isla Zapara y Santa Rosa de Agua, estos fueron depositados en la colección de Invertebrados acuáticos de la Facultad Experimental de Ciencias, Universidad del Zulia, bajo los números de catálogos: MBLUZ2503, MBLUZ-2515, MBLUZ-2516 y MBLUZ-2517. Estos registros confirman la presencia de P. monodon en los cuatro sectores que conforman el Sistema Lago de Maracaibo (Golfo de Venezuela, Bahía El Tablazo, Estrecho del Lago y el Lago de Maracaibo), indicando un posible aumento de las poblaciones de esta especie en la región. Se requieren futuras investigaciones enfocadas a evaluar si el estado poblacional del camarón tigre en el Sistema del Lago de Maracaibo, así como para el diseño de estrategias efectivas para el manejo de este recurso

Electrochemical Impedance Spectroscopy (EIS): A Review Study of Basic Aspects of the Corrosion Mechanism Applied to Steels

AC impedance measurements have been applied for over twenty years in electrochemistry and physics to investigate the electrical properties of conductive materials and their interfaces using an external electrical impulse (VOLTAGE, V or CURRENT, I) as driving force. Furthermore, its application has recently appeared to be destined in the Biotechnology field as an effective tool for rapid microbiologic diagnosis of living organism in situ. However, there is no doubt that the electrochemical impedance spectroscopy (EIS) is still one of the most useful techniques around the world for metal corrosion control and its monitoring. Corrosion has long been recognized as one of the most expensive stumbling blocks that concern many industries and government agencies, because it is a steel destructive phenomenon that occurs due to the chemical interaction with aqueous environments and takes place at the interface between metal and electrolyte producing an electrical charge transfer or ion diffusion process. Consequently, it is experimentally possible to determine through the EIS technique the mechanism and control that kinectics of corrosion reactions encounter. First, EIS data is collected through a potentiostat/ galvanostat apparatus. After, it is fitted to a mathematical model (i.e. an equivalent electrical circuit, EEC) for its interpretation and analysis, fundamentally seeking a meaningful physical interpretation. Finally, this review reports some basic aspects of the corrosion mechanism applied to steels through the experimental EIS response using Nyquist or Bode plots. Examples are given for different applied electrochemical impedance cases in which steel is under study intentionally exposed to a corrosive aqueous solution by applying a sinusoidal potential at various test conditions

Skin Bleaching Among African and Afro-Caribbean Women in New York City: Primary Findings from a P30 Pilot Study

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Coinciding with the increase in sequenced bacteria, mining of bacterial genomes for biosynthetic gene clusters (BGCs) has become a critical component of natural product discovery. The order Myxococcales, a reputable source of biologically active secondary metabolites, spans three suborders which all include natural product producing representatives. Utilizing the BiG-SCAPE-CORASON platform to generate a sequence similarity network that contains 994 BGCs from 36 sequenced myxobacteria deposited in the antiSMASH database, a total of 843 BGCs with lower than 75% similarity scores to characterized clusters within the MIBiG database are presented. This survey provides the biosynthetic diversity of these BGCs and an assessment of the predicted chemical space yet to be discovered. Considering the mere snapshot of myxobacteria included in this analysis, these untapped BGCs exemplify the potential for natural product discovery from myxobacteria

Stochastic evolutionary game dynamics

In this review, we summarize recent developments in stochastic evolutionary game dynamics of finite populations.Comment: To appear in "Reviews of Nonlinear Dynamics and Complexity" Vol. II, Wiley-VCH, 2009, edited by H.-G. Schuste

Resource Heterogeneity Moderates the Biodiversity-Function Relationship in Real World Ecosystems

Numerous recent studies have tested the effects of plant, pollinator, and predator diversity on primary productivity, pollination, and consumption, respectively. Many have shown a positive relationship, particularly in controlled experiments, but variability in results has emphasized the context-dependency of these relationships. Complementary resource use may lead to a positive relationship between diversity and these processes, but only when a diverse array of niches is available to be partitioned among species. Therefore, the slope of the diversity-function relationship may change across differing levels of heterogeneity, but empirical evaluations of this pattern are lacking. Here we examine three important functions/properties in different real world (i.e., nonexperimental) ecosystems: plant biomass in German grasslands, parasitism rates across five habitat types in coastal Ecuador, and coffee pollination in agroforestry systems in Indonesia. We use general linear and structural equation modeling to demonstrate that the effect of diversity on these processes is context dependent, such that the slope of this relationship increases in environments where limiting resources (soil nutrients, host insects, and coffee flowers, respectively) are spatially heterogeneous. These real world patterns, combined with previous experiments, suggest that biodiversity may have its greatest impact on the functioning of diverse, naturally heterogeneous ecosystems

Plant Diversity Surpasses Plant Functional Groups and Plant Productivity as Driver of Soil Biota in the Long Term

One of the most significant consequences of contemporary global change is the rapid decline of biodiversity in many ecosystems. Knowledge of the consequences of biodiversity loss in terrestrial ecosystems is largely restricted to single ecosystem functions. Impacts of key plant functional groups on soil biota are considered to be more important than those of plant diversity; however, current knowledge mainly relies on short-term experiments.We studied changes in the impacts of plant diversity and presence of key functional groups on soil biota by investigating the performance of soil microorganisms and soil fauna two, four and six years after the establishment of model grasslands. The results indicate that temporal changes of plant community effects depend on the trophic affiliation of soil animals: plant diversity effects on decomposers only occurred after six years, changed little in herbivores, but occurred in predators after two years. The results suggest that plant diversity, in terms of species and functional group richness, is the most important plant community property affecting soil biota, exceeding the relevance of plant above- and belowground productivity and the presence of key plant functional groups, i.e. grasses and legumes, with the relevance of the latter decreasing in time.Plant diversity effects on biota are not only due to the presence of key plant functional groups or plant productivity highlighting the importance of diverse and high-quality plant derived resources, and supporting the validity of the singular hypothesis for soil biota. Our results demonstrate that in the long term plant diversity essentially drives the performance of soil biota questioning the paradigm that belowground communities are not affected by plant diversity and reinforcing the importance of biodiversity for ecosystem functioning