The effect of poly(lactide)-poly(carbonate) based block copolymers on the morphology and crystallization of double crystalline poly(lactide)/poly(ε-caprolactone) blends

Block copolymers of poly(lactide) and poly(carbonate) were synthetized in three different compositions and characterized by 1H-NMR and ATR analyses. The compatibilization effect of this copolymers on 80/20 (w/w%) PLA/PCL blend was evaluated. SEM micrographs show that all the blends exhibit the typical sea-island morphology characteristic of immiscible blends with PCL finely dispersed in droplets on a PLA matrix. Upon the addiction of the copolymers a reduction on PCL droplets size is observable. At the same time, a Tg depression of the PLA phase is detected when the copolymers are added in the blend. These results indicate that these copolymers are effective as compatibilizers. The copolymer that acts as the best compatibilizer is the one characterized by the same amount of PLA and PC as repeating units. As result, in the blend containing this copolymer PLA phase exhibits the highest spherulitic growth rate. An analyses on PLA phase crystallization behaviour from the glassy state within the blends was evaluated by DSC experiments. Isothermal cold crystallization of the PLA phase is enhanced up an order of magnitude upon the blending with PCL. Annealing experiments demonstrated that the crystallization of the PCL phase induces the formation of active nuclei in PLA when cooled above cooled below Tg. When the crystallization rate of PCL is retarded, a reduction on PLA nucleation is observed.

Towards structured, block-based PDF

The Portable Document Format (PDF), defined by Adobe Systems Inc. as the basis of its Acrobat product range, is discussed in some detail. Particular emphasis is given to its flexible object-oriented structure, which has yet to be fully exploited. It is currently used to represent not logical structure but simply a series of pages and associated resources. A definition of an Encapsulated PDF (EPDF) is presented, in which EPDF blocks carry with them their own resource requirements, together with geometrical and logical information. A block formatter called Juggler is described which can lay out EPDF blocks from various sources onto new pages. Future revisions of PDF supporting uniquely-named EPDF blocks tagged with semantic information would assist in composite-pagemakeup and could even lead to fully revisable PDF.

The cytokinesis-block micronucleus (CBMN) assay in human populations exposed to styrene: a systematic review and meta-analysis

Styrene is a building-block of several compounds used in a wide array of materials and products. The most important human exposure to this substance occurs in industrial settings, especially among reinforced-plastics industry workers. The effect of occupational exposure to styrene on cytogenetics biomarkers has been previously reviewed with positive association observed for chromosomal aberrations, and inconclusive data for the micronucleus assay. Some limitations were noted in those studies, including inadequate exposure assessment and poor epidemiological design. Furthermore, in earlier studies micronuclei frequency was measured with protocols not as reliable as cytokinesis-block micronucleus (CBMN) assay. Aim of the present systematic review and meta-analysis is to investigate genomic instability and DNA damage as measured by the CBMN assay in lymphocytes of subjects exposed to styrene. A total of 11 studies published between 2004 and 2012 were included in the meta-analysis encompassing 479 styrene-exposed workers and 510 controls. The quality of each study was estimated by a quality scoring system which ranked studies according to the consideration of major confounders, exposure characterization, and technical parameters. An overall increase of micronuclei frequencies was found in styrene-exposure workers when compared to referents (meta-MR 1.34; 95% CI 1.18–1.52), with significant increases achieved in six individual studies. The consistency of results in individual studies, the independence of this result from major confounding factors and from the quality of the study strengthens the reliability of risk estimates and supports the use of the CBMN assay in monitoring genetic risk in styrene workers.

Tau Functions and the Limit of Block Toeplitz Determinants

International audience

Is the supply of long-term debt independent of the term premia? Evidence from Portugal

An important assumption in the statistical analysis of the financial market effects of the central bank’s large scale asset purchase program is that the "long-term debt stock variables were exogenous to term premia". We test this assumption for a small open economy in a currency union over the period 2000M3 to 2015M10, via the determinants of short- term financing relative to long-term financing. Empirical estimations indicate that the maturity composition of debt does not respond to the level of interest rate or to the term structure. These findings suggest a lower adherence to the cost minimization mandate of debt management. However, we find that volatility and relative market size respectively decrease and increase short-term financing relative to long-term financing, while it decreases with an increase in government indebtedness.

Programa de gestión de seguridad y salud ocupacional para la empresa Celo-Block, S.A. de C.V., ubicada en el municipio de Guazapa departamento de San Salvador.

La empresa Celo- Block S.A. de C.V. a lo largo de su historia como centro de trabajo, cuenta con numerosos casos de accidentes de trabajo, por la falta de un programa dirigido a la prevención de riesgos ocupacionales. Es por ello, que se ha considerado diseñar un Programa de Gestión de Seguridad y Salud Ocupacional, teniendo como base principal los lineamientos contenidos en los artículos 8 y 13 de la Ley General de Prevención de Riesgos en los Lugares de Trabajo. Todo ello con la intención de proteger a los trabajadores enfocando la investigación en el análisis de las condiciones físicas actuales, en materia de Seguridad y Salud Ocupacional. La Seguridad y Salud Ocupacional aplicada a los lugares de trabajo tiene como objetivo salvaguardar la vida de los trabajadores, a la vez proteger la salud y la integridad física de los mismos, por medio de la puesta en práctica de medidas encaminadas a proporcionar condiciones óptimas en el trabajo. Por lo que la Seguridad y Salud Ocupacional debería ser uno de los puntos clave de cualquier empresa. Dicha propuesta busca como objetivo principal, mejorar el ambiente de trabajo, y contribuir a la reducción de accidentes que pueden lesionar a los trabajadores. Por medio de la elaboración de una política que sirva de guía para la prevención de accidentes ocupacionales, según lo establece la Ley General de Prevención de Riesgos en los Lugares de Trabajo. La metodología utilizada en la investigación, consistió en la elaboración de un diagnóstico, que permitió conocer la situación actual en materia de Seguridad y Salud Ocupacional en la empresa, el método de investigación que se implementó fue el análisis, el tipo de investigación que se realizó fue el descriptivo, el diseño de la investigación fue la no experimental, y las fuentes de investigación fueron las primarias y secundarias y se logró a través de las técnicas de investigación como entrevista, encuestas, y observación directa, realizar un mapa de riesgos y localizar los puntos más críticos a los que se encuentran expuestos los trabajadores dentro de su jornada laboral. La sistemática anterior, permitió obtener los siguientes resultados: que la empresa no ha establecido formalmente un Comité de Seguridad y Salud Ocupacional y que por lo tanto no cuenta con la estructuración formal de un Programa de Gestión de Seguridad y Salud Ocupacional que contenga planes políticas y procedimientos preventivos que ayuden al bienestar de los trabajadores. El área donde ocurren más accidentes es en Descargado y Colocado debido a que es donde se encuentran la mayoría de factores de riesgo. De acuerdo a la encuesta y la inspección realizada, la empresa carece de señalización en las diferentes áreas, y por último la empresa no posee registro detallado de accidentes laborales, entre otros. Para poder superar las deficiencias encontradas, se realizan las siguientes recomendaciones contenidas dentro de la propuesta de esta investigación: la creación y funcionamiento de un Comité de Seguridad y Salud Ocupacional, la creación de políticas por parte de las autoridades de la empresa, el equipamiento de seguridad así como la compra de los insumos básicos de primeros auxilios para la atención de accidentes, la implementación de capacitaciones tanto para el Comité de Seguridad y Salud Ocupacional así como también para el resto de los trabajadores, y simulacros los cuales se recomienda que realicen por lo menos dos veces al año. Todo lo anterior, permitirá obtener grandes beneficios a la empresa como la disminución de riesgos de accidentes y enfermedades profesionales, fomentar una cultura de prevención, cumplir con la legislación actual en la materia y evitarse infracciones ocasionadas por incumplimiento de la misma.

3D Block Modeling and Reserve Estimation of a Garnet Deposit

The purpose of this project is to develop a three-dimensional block model for a garnet deposit in the Alder Gulch, Madison County, Montana. Garnets occur in pre-Cambrian metamorphic Red Wash gneiss and similar rocks in the vicinity. This project seeks to model the percentage of garnet in a deposit called the Section 25 deposit using the Surpac software. Data available for this work are drillhole, trench and grab sample data obtained from previous exploration of the deposit. The creation of the block model involves validating the data, creating composites of assayed garnet percentages and conducting basic statistics on composites using Surpac statistical tools. Variogram analysis will be conducted on composites to quantify the continuity of the garnet mineralization. A three-dimensional block model will be created and filled with estimates of garnet percentage using different methods of reserve estimation and the results compared.

The conjugate gradient partitioned block frequency-domain for multichannel adaptive filtering

The conjugate gradient is the most popular optimization method for solving large systems of linear equations. In a system identification problem, for example, where very large impulse response is involved, it is necessary to apply a particular strategy which diminishes the delay, while improving the convergence time. In this paper we propose a new scheme which combines frequency-domain adaptive filtering with a conjugate gradient technique in order to solve a high order multichannel adaptive filter, while being delayless and guaranteeing a very short convergence time.

Reply to the Editor—Prevalence of interatrial block during lifetime

SIN FINANCIACIÓN

Interatrial block and atrial arrhythmias in centenarians: Prevalence, associations, and clinical implications

Data are lacking on the characteristics of atrial activity in centenarians, including interatrial block (IAB). The aim of this study was to describe the prevalence of IAB and auricular arrhythmias in subjects older than 100 years and to elucidate their clinical implications. We studied 80 centenarians (mean age 101.4 ± 1.5 years; 21 men) with follow-ups of 6–34 months. Of these 80 centenarians, 71 subjects (88.8%) underwent echocardiography. The control group comprised 269 septuagenarians. A total of 23 subjects (28.8%) had normal P wave, 16 (20%) had partial IAB, 21 (26%) had advanced IAB, and 20 (25.0%) had atrial fibrillation/flutter. The IAB groups exhibited premature atrial beats more frequently than did the normal P wave group (35.1% vs 17.4%; P < .001); also, other measurements in the IAB groups frequently fell between values observed in the normal P wave and the atrial fibrillation/flutter groups. These measurements included sex preponderance, mental status and dementia, perceived health status, significant mitral regurgitation, and mortality. The IAB group had a higher previous stroke rate (24.3%) than did other groups. Compared with septuagenarians, centenarians less frequently presented a normal P wave (28.8% vs 53.5%) and more frequently presented advanced IAB (26.3% vs 8.2%), atrial fibrillation/flutter (25.0% vs 10.0%), and premature atrial beats (28.3 vs 7.0%) (P < .01). Relatively few centenarians (<30%) had a normal P wave, and nearly half had IAB. Our data suggested that IAB, particularly advanced IAB, is a pre–atrial fibrillation condition associated with premature atrial beats. Atrial arrhythmias and IAB occurred more frequently in centenarians than in septuagenarians.

SOUTH CAROLINA COMMUNITY BLOCK GRANTS FOR EDUCATION PILOT PROGRAMS

The South Carolina General Assembly created the South Carolina Community Block Grant for Education Pilot Program by Proviso 1.94 in the 2014-15 General Appropriation Act. The intent of the proviso is to encourage public school districts and district entrepreneurial public educators to undertake state-of-the-art initiatives to improve student learning and to share the results with the state’s public education community. Although community partnerships were the focus of the grant, school districts were the lead agencies on the grant were directed by proviso to provide reports, summaries and items for the evaluation component of the grant. Through this proviso, one million dollars was allocated for the block grants with direct allocations to school districts. One hundred percent of the funds were allocated to school districts. No grant award was to exceed $250,000 annually unless the grants committee found that exceptional circumstances warranted exceeding this amount.

South Carolina Community Block Grants for Education Pilot Programs: Year 1 Report

The South Carolina General Assembly created the South Carolina Community Block Grant for Education Pilot Program by Proviso 1.94 in the 2014-15 General Appropriation Act. The purpose of the proviso was to encourage and sustain partnerships between a community and its public school district for the implementation of innovative, state-of-the-art education initiatives and models to improve learning. Any public school, including a charter school, was eligible to submit a grant application. The proviso asserts that the success of the grant program is best served when there is vigorous community support, which is integral to the development and implementation on innovative initiatives for young people. Through this proviso, one million dollars was allocated for the block grants with direct allocations to school districts. Grants awarded were to be implemented for a period of one year beginning July 1, 2015 until June 30, 2016.

Heaven's Sense: a novel / At hand-grips with ruin: the psychology of writer's block

There is a significant attitude of scepticism when it comes to belief in the existence of writer's block as a valid psychological phenomenon, alongside what might be described as the "Tortured Artist Personality". It is contended here that both writer's block and the "Tortured Artist Personality" do exist in a minority of professional and aspiring fiction writers, and furthermore that these phenomena are forms of personality behaviour that have already been well-catalogued by the academic fields of psychiatry, psychology and psychotherapy: specifically, writer's block is a form of unconscious maladaptive procrastination - expressed through avoidance coping or escape coping behaviour - which in turn arises from the fully-accepted personality trait of perfectionism. Aspects of perfectionism, together with various sub-scale traits and mediators, are also the key components in at least one form of "Tortured Artist Personality". This paper lays out the extensive evidence for these assertions, using existing research in the fields of psychology, psychiatry, psychotherapy and neuroscience.