945 resultados para Fractions. Activities. Operations With Fractions


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We report on a father and daughter with hand-foot-genital syndrome (HFGS) with typical skeletal and genitourinary anomalies due to a 14-residue polyalanine expansion in HOXA13. This is the largest (32 residues) polyalanine tract so far described for any polyalanine mutant protein. Polyalanine expansion results in protein misfolding, cytoplasmic aggregation and degradation; however, HOXA13 polyalanine expansions appear to act as loss of function mutations in contrast to gain of function for HOXD13 polyalanine expansions. To address this paradox we examined the cellular consequences of polyalanine expansions on HOXA13 protein using COS cell transfection and immunocytochemistry. HOXA13 polyalanine expansion proteins form cytoplasmic aggregates, and distribution between cytoplasmic aggregates or the nucleus is polyalanine tract size-dependent. Geldanamycin, an Hsp90 inhibitor, reduces the steady-state abundance of all polyalanine-expanded proteins in transfected cells. We also found that wild-type HOXA13 or HOXD13 proteins are sequestered in HOXA13 polyalanine expansion cytoplasmic aggregates. Thus, the difference between HOXA13 polyalanine expansion loss-of-function and HOXD13 polyalanine expansion dominant-negative effect is not the ability to aggregate wild-type group 13 paralogs but perhaps to variation in activities associated with refolding, aggregation or degradation of the proteins.

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BACKGROUND: Theodor Kocher, surgeon and Nobel laureate, has influenced thyroid surgery all over the world: his treatment for multinodular goiter-subtotal thyroidectomy-has been the "Gold Standard" for more than a century. However, based on a new understanding of molecular growth mechanisms in goitrogenesis, we set out to evaluate if a more extended resection yields better results. METHODS: Four thousand three hundred and ninety-four thyroid gland operations with 5,785 "nerves at risk" were prospectively analyzed between 1972 and 2002. From 1972 to 1990, the limited Kocher resections were performed, and from 1991 to 2002 a more radical resection involving at least a hemithyroidectomy was performed. RESULTS: The incidence of postoperative nerve palsy was 3.6%; in the first study period and 0.9%; in the second (P < 0.001, Fisher's exact). Postoperative hypoparathyroidism decreased from 3.2%; in the first period to 0.64%; in the second (P < 0.01). The rate of reoperation for recurrent disease was 11.1%; from 1972 to 1990 and 8.5%; from 1991 to 2002 (P < 0.01). CONCLUSIONS: Extended resection for multinodular goiter not only significantly reduced morbidity, but also decreased the incidence of operations for recurrent disease. Our findings in a large cohort corroborate the suggestions that Kocher's approach should be replaced by a more radical resection, which actually was his original intention more than 130 years ago.

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Creating Lakes from Open Pit Mines: Processes and Considerations, Emphasis on Northern Environments. This document summarizes the literature of mining pit lakes (through 2007), with a particular focus on issues that are likely to be of special relevance to the creation and management of pit lakes in northern climates. Pit lakes are simply waterbodies formed by filling the open pit left upon the completion of mining operations with water. Like natural lakes, mining pit lakes display a huge diversity in each of these subject areas. However, pit lakes are young and therefore are typically in a non-equilibrium state with respect to their rate of filling, water quality, and biology. Separate sections deal with different aspects of pit lakes, including their morphometry, geology, hydrogeology, geochemistry, and biology. Depending on the type and location of the mine, there may be opportunities to enhance the recreational or ecological benefits of a given pit lake, for example, by re-landscaping and re-vegetating the shoreline, by adding engineered habitat for aquatic life, and maintaining water quality. The creation of a pit lake may be a regulatory requirement to mitigate environmental impacts from mining operations, and/or be included as part of a closure and reclamation plan. Based on published case studies of pit lakes, large-scale bio-engineering projects have had mixed success. A common consensus is that manipulation of pit lake chemistry is difficult, expensive, and takes many years to achieve remediation goals. For this reason, it is prudent to take steps throughout mine operation to reduce the likelihood of future water quality problems upon closure. Also, it makes sense to engineer the lake in such a way that it will achieve its maximal end-use potential, whether it be permanent and safe storage of mine waste, habitat for aquatic life, recreation, or water supply.

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Detector uniformity is a fundamental performance characteristic of all modern gamma camera systems, and ensuring a stable, uniform detector response is critical for maintaining clinical images that are free of artifact. For these reasons, the assessment of detector uniformity is one of the most common activities associated with a successful clinical quality assurance program in gamma camera imaging. The evaluation of this parameter, however, is often unclear because it is highly dependent upon acquisition conditions, reviewer expertise, and the application of somewhat arbitrary limits that do not characterize the spatial location of the non-uniformities. Furthermore, as the goal of any robust quality control program is the determination of significant deviations from standard or baseline conditions, clinicians and vendors often neglect the temporal nature of detector degradation (1). This thesis describes the development and testing of new methods for monitoring detector uniformity. These techniques provide more quantitative, sensitive, and specific feedback to the reviewer so that he or she may be better equipped to identify performance degradation prior to its manifestation in clinical images. The methods exploit the temporal nature of detector degradation and spatially segment distinct regions-of-non-uniformity using multi-resolution decomposition. These techniques were tested on synthetic phantom data using different degradation functions, as well as on experimentally acquired time series floods with induced, progressively worsening defects present within the field-of-view. The sensitivity of conventional, global figures-of-merit for detecting changes in uniformity was evaluated and compared to these new image-space techniques. The image-space algorithms provide a reproducible means of detecting regions-of-non-uniformity prior to any single flood image’s having a NEMA uniformity value in excess of 5%. The sensitivity of these image-space algorithms was found to depend on the size and magnitude of the non-uniformities, as well as on the nature of the cause of the non-uniform region. A trend analysis of the conventional figures-of-merit demonstrated their sensitivity to shifts in detector uniformity. The image-space algorithms are computationally efficient. Therefore, the image-space algorithms should be used concomitantly with the trending of the global figures-of-merit in order to provide the reviewer with a richer assessment of gamma camera detector uniformity characteristics.

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Tree ring–based temperature reconstructions form the scientific backbone of the current global change debate. Although some European records extend into medieval times, high-resolution, long-term, regional-scale paleoclimatic evidence is missing for the eastern part of the continent. Here we compile 545 samples of living trees and historical timbers from the greater Tatra region to reconstruct interannual to centennial-long variations in Eastern European May–June temperature back to 1040 AD. Recent anthropogenic warming exceeds the range of past natural climate variability. Increased plague outbreaks and political conflicts, as well as decreased settlement activities, coincided with temperature depressions. The Black Death in the mid-14th century, the Thirty Years War in the early 17th century, and the French Invasion of Russia in the early 19th century all occurred during the coldest episodes of the last millennium. A comparison with summer temperature reconstructions from Scandinavia, the Alps, and the Pyrenees emphasizes the seasonal and spatial specificity of our results, questioning those large-scale reconstructions that simply average individual sites.

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Debuggers are crucial tools for developing object-oriented software systems as they give developers direct access to the running systems. Nevertheless, traditional debuggers rely on generic mechanisms to explore and exhibit the execution stack and system state, while developers reason about and formulate domain-specific questions using concepts and abstractions from their application domains. This creates an abstraction gap between the debugging needs and the debugging support leading to an inefficient and error-prone debugging effort. To reduce this gap, we propose a framework for developing domain-specific debuggers called the Moldable Debugger. The Moldable Debugger is adapted to a domain by creating and combining domain-specific debugging operations with domain-specific debugging views, and adapts itself to a domain by selecting, at run time, appropriate debugging operations and views. We motivate the need for domain-specific debugging, identify a set of key requirements and show how our approach improves debugging by adapting the debugger to several domains.

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After the NEEM (Greenland) deep ice-core drilling was declared terminated with respect to developing stratigraphic climate reconstructions, efforts were turned toward collecting basal ice-sheet debris and, if possible, drilling into the bedrock itself. In 2010, several meters of banded debris-rich ice were obtained under normal ice-drilling operations with the NEEM version of the Hans Tausen (HT) drill, but further penetration was obstructed by a rock in the path of the drill head at 2537.36 m. During short campaigns in 2011 and 2012, attempts were made to penetrate further using various reinforced ice cutters mounted on the HT drill head, tailored to cut through rock. These had some success in penetrating coarse material, but produced severely damaged cutters. Additionally a 51 mm diameter diamond cutting tipped rock drill was adapted to fit the NEEM drill. With this device, several additional meters of core containing subglacial sediments, rocks and rock fragments were collected. With these tools 1.39 m of additional material were obtained during the 2011 field season, and 7.1 m during 2012. Subglacial water refreezing into the newly formed borehole hindered further penetration, and the bedrock interface was not reached before final closure of the NEEM Camp.

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BACKGROUND Genome-wide association studies have linked CYP17A1 coding for the steroid hormone synthesizing enzyme 17α-hydroxylase (CYP17A1) to blood pressure (BP). We hypothesized that the genetic signal may translate into a correlation of ambulatory BP (ABP) with apparent CYP17A1 activity in a family-based population study and estimated the heritability of CYP17A1 activity. METHODS In the Swiss Kidney Project on Genes in Hypertension, day and night urinary excretions of steroid hormone metabolites were measured in 518 participants (220 men, 298 women), randomly selected from the general population. CYP17A1 activity was assessed by 2 ratios of urinary steroid metabolites: one estimating the combined 17α-hydroxylase/17,20-lyase activity (ratio 1) and the other predominantly 17α-hydroxylase activity (ratio 2). A mixed linear model was used to investigate the association of ABP with log-transformed CYP17A1 activities exploring effect modification by urinary sodium excretion. RESULTS Daytime ABP was positively associated with ratio 1 under conditions of high, but not low urinary sodium excretion (P interaction <0.05). Ratio 2 was not associated with ABP. Heritability estimates (SE) for day and night CYP17A1 activities were 0.39 (0.10) and 0.40 (0.09) for ratio 1, and 0.71 (0.09) and 0.55 (0.09) for ratio 2 (P values <0.001). CYP17A1 activities, assessed with ratio 1, were lower in older participants. CONCLUSIONS Low apparent CYP17A1 activity (assessed with ratio 1) is associated with elevated daytime ABP when salt intake is high. CYP17A1 activity is heritable and diminished in the elderly. These observations highlight the modifying effect of salt intake on the association of CYP17A1 with BP.

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The research study was intended to evaluate the effectiveness of Inner City Development's (I.C.D.) Cooperative Home School, an educational alternative program to the Title I public schools of San Antonio's West Side community. The study investigated students', parents' and tutors' perception of parental involvement and educational resources. The study also investigated each student's academic achievement. ^ The study found that students progressed toward expected math proficiency at a faster rate than they did in reading proficiency. However, because the target population size was small and a comparison group was not used, the results of this study are only suggestive. This research also indicated that study subjects believed students' quality and level of education increased substantially since program exposure. Study subjects mainly attributed the students' strides in academic performance to the increased amount of individualized attention students received in the small twelve-student class size. Study subjects were more satisfied with the home school's educational resources than those of the Title I public schools. Study subjects also perceived that parental involvement both at home and at school increased since enrollment in the home school program because: (1) there were more opportunities for involvement in the home school; and (2) parents felt closer to the tutors than the teachers in public school. ^ This evaluation also suggested improvements to program operations. With the help of additional volunteers, I.C.D. program operators could improve collection and organization of academic records. Furthermore, as suggested by program participants, science could be added to the curriculum. Lastly, a formal tutor orientation could be implemented to familiarize and train tutors on classroom management procedures. ^

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Objectives. The objectives of this report were to describe current best standards in online education, class competencies, class objectives, class activities and to compare the class competencies, objectives and activities undertaken with the current best practices in online teaching and to provide a list of recommendations based on the most efficacious practices. ^ Methods. Utilizing the key words- online teaching, national standards, quality, online courses, I: (1) conducted a search on Google to find the best standard for quality online courses; the search yielded National Standards for Quality Online Teaching as the gold standard in online course quality; (2) specified class objectives and competencies as well as major activities undertaken as a part of the class. Utilizing the Southern Regional Education Board evaluation checklist for online courses, I: (1) performed an analysis comparing the class activities, objectives, and competencies with the current best standards; (2) utilized the information obtained from the analysis and class experiences to develop recommendations for the most efficacious online teaching practices. ^ Results. The class met the criteria set by the Southern Regional Education Board for evaluating online classes completely in 75%, partially in 16% and did not meet the criteria in 9% cases. The majority of the parameters in which the class did not meet the standards (4 of 5) were due to technological reasons beyond the scope of the class instructor, teaching assistant and instructional design. ^ Discussion. Successful online teaching requires awareness of technology, good communication, methods, collaboration, reflection and flexibility. Creation of an online community, engaging online learners and utilizing different learning styles and assessment methods promote learning. My report proposes that online teaching should actively engage the students and teachers with multiple interactive strategies as evidenced from current best standards of online education and my “hands-on” work experience. ^ Conclusion. The report and the ideas presented are intended to create a foundation for efficacious practice on the online teaching platform. By following many of the efficacious online practices described in the report and adding from their own experiences, online instructors and teaching assistants can contribute to effective online learning. ^

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Habitual consumption of sugar-sweetened beverages (SSB) has been reliably linked to obesity in adolescents. A wide variety of beverages sweetened with sugar are available to this population. The objective of this secondary data analysis was to assess the consumption of SSB by category and to identify behaviors that occur concurrently with the consumption of soda, sport drinks and fruit-flavored drinks in high school students. The analysis used self-reported survey data from 97 adolescents ages 14 to 18. SSB categories considered in the consumption analysis included regular soda, sports drinks, fruit-flavored drinks (FFD), iced tea, coffee drinks and energy drinks. The mean weekly sweetened beverage load in this population, calculated from the frequency and amount of consumption, was 145 ounces when all categories were considered. When SSB categories were considered independently, sports drinks (45 oz.) had the highest contribution to the mean sweetened beverage load followed by FFD (41 oz.), iced tea (27 oz.), soda (26 oz.) coffee drinks (15 oz.) and energy drinks (2 oz.). Sweetened beverage load was higher in boys (151 oz.) than girls (138 oz.) and was highest in Hispanics (159 oz.) followed by whites (152 oz.), blacks (137 oz.) and others (104 oz.). Behaviors that occurred on a usual basis during SSB consumption included watching TV, eating a family meal, eating salty and fried foods, being on the computer and hanging out with friends. Activities concurrent with sports drink consumption included physical activity behaviors whereas soda and FFD did not. Sports drink and FFD consumption commonly co-occurred with fruit consumption. Multiple SSB categories contribute to the total SSB consumption and the common dietary and activity behaviors are distinct between categories. Several of the concurrent behaviors point to the importance of home beverage availability, and to the influence that parents and peers have on SSB consumption. Identifying and assessing intervention strategies targeted to specific beverage categories could be an important step in behavioral intervention research aimed at reducing added sugar consumption, and ultimately, promote a healthy weight in adolescents. ^

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Approximately 33% of clinical breast carcinomas require estrogens to proliferate. Epidemiological data show that insulin resistance and diabetes mellitus is 2–3 times more prevalent in women with breast cancer than those with benign breast lesions, suggesting a clinical link between insulin and estradiol. Insulin and estradiol have a synergistic effect on the growth of MCF7 breast cancer cells, and long-term estradiol treatment upregulates the expression of the key insulin signaling protein IRS-1. The goal of this study was to further define the mechanism(s) of cross-talk between insulin and estradiol in regulating the growth of breast cancer. Using MCF7 cells, acute treatment with insulin or estradiol alone was found to stimulate two activities associated with growth: Erk MAP kinase and PI 3-kinase. However, combined acute treatment had an antagonistic effect on both activities. Acute estradiol treatment inhibited the insulin-stimulated tyrosine phosphorylation of IRS-1 while increasing its serine phosphorylation; the serine phosphorylation was attenuated by the PI 3-kinase inhibitor wortmannin. The acute antagonism observed with combined estradiol and insulin are not consistent with the long-term synergistic effect on growth. In contrast, chronic estradiol treatment enhanced the insulin-sensitivity of breast cancer cells as measured by increases in total cellular insulin-stimulated tyrosine phosphorylation of IRS-1 and activation of PI 3-kinase. Estradiol stimulation of gene transcription was found to require PI 3-kinase activity but not MAP kinase activity. Insulin alone had no effect on ER transcriptional activity, but chronic treatment in combination with estradiol resulted in synergism of ER transcription. The synergistic effect of insulin and estradiol on MCF7 cell growth was also found to require PI 3-kinase but not MAP kinase activity. Therefore, chronic estradiol treatment increases insulin stimulation of PI 3-kinase, and PI 3-kinase is required for estradiol stimulation of gene transcription alone and in combined synergy with insulin. These data demonstrate that PI 3-kinase is the locus for the cross-talk between insulin and estradiol which results in enhanced breast cancer growth with long-term exposure to both hormones. This may have important clinical implications for women with high risk for breast cancer and/or diabetes mellitus. ^

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Con el propósito de contribuir al conocimiento de las lógicas y tendencias de la expansión residencial en áreas periurbanas y su impronta en la organización futura de las ciudades medias, tendiente al logro de una relación armónica entre la actividad residencial y las otras actividades socioeconómicas que se presentan en dichas áreas, en la presente Tesis doctoral se aborda el estudio del proceso de expansión residencial que se han venido desarrollando en el espacio periurbano del Partido de La Plata desde principios de los años '90 hasta nuestros días. Para tal fin, se profundiza en el estudio de espacios periurbanos, caracterizados por su dinamismo, heterogeneidad y complejidad. En relación a los espacios residenciales que se desarrollan en estas áreas periféricas del Partido, fueron reconocidas tres tendencias diferenciadas: a) el proceso de urbanización cerrada, con tendencias al aislamiento de viviendas y complejos habitacionales, b) la "producción de periferia" relacionada con los sectores de población que no consiguen acceder al mercado formal de la tierra y la vivienda, asociada por lo general a modalidades de asentamiento espontáneo; y c) la ocupación gradual de baldíos urbanos con escasa o nula provisión de servicios y redes de infraestructura. En la presente Tesis se profundizará en las dos primeras de estas modalidades expansivas, indagándose en las lógicas de los distintos actores -sociales, políticos y económicos- que intervienen en el proceso urbano expansivo que hemos denominado "formal cerrado" e "informal abierto", respectivamente. La hipótesis que guía nuestro trabajo plantea que la expansión urbana en el Partido de La Plata trae aparejada una competencia por el territorio entre diferentes usos del suelo y actividades, con el consecuente incremento en los precios de la tierra, abandono de los sectores de bajos ingresos como habitantes originales y disminución del uso de tierra rural. Para dar respuesta a los objetivos e hipótesis planteados en nuestra Tesis, los criterios metodológicos adoptados parten de considerar al territorio como un sistema complejo. En este marco, el abordaje desde una visión sistémica y de la complejidad de nuestro objeto de estudio necesita de un abordaje dialéctico y de la convergencia metodológica para obtener distintos puntos de vista sobre el mismo. En el desarrollo de esta Tesis se han utilizado como herramientas de investigación: el método del estudio de caso, la construcción tipológica, la realización de entrevistas semiestructuradas y en profundidad, la utilización de modelos y la construcción de escenarios urbanos. Finalmente, producto de estos años de investigación en la temática, se arribó a las siguientes conclusiones, que han sido estructuradas en cinco apartados principales en función de su carácter predominantemente teórico, empírico, metodológico y/o propositivo, a saber: 1. el periurbano: ¿espacio de competencia o complementariedad?; 2. la construcción de tipologías como camino explicativo en materia de espacios periurbanos; 3. las lógicas residenciales periféricas: la "privatópolis" y la "precariópolis"; 4. las tendencias residenciales periféricas y los desafíos de la planificación urbana, y 5. nuevos interrogantes y perspectivas surgidos de esta Tesis.

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En el presente trabajo me interesa considerar los modos en que Ricardo Piglia se ha constituido como escritor que lee y ha hecho de esta operación una clave de sus materiales, no sólo en la crítica argentina, sino desde su doble localización como profesor en Estados Unidos y Buenos Aires, para articular estas operaciones con algunos debates sobre la constitución del canon de la crítica argentina a partir de protocolos críticos y estéticos, en la formulación de concepciones de la literatura y del crítico

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En este artículo abordaremos cómo se relacionan las experiencias formativas vinculadas al trabajo rural, las identificaciones y los conflictos ambientales en San Ignacio, Misiones (Argentina). Nos interesa problematizar cómo los aprendizajes ligados a las tareas rurales se vinculan con las auto-adscripciones de los sujetos, teniendo como referencia las categorías de actores sociales agrarios regionales y las denominaciones que provienen de agendas estatales de intervención. Estos procesos acontecen en un contexto de creciente concentración de propiedades que se destinan a la explotación forestal, donde observamos, en algunos casos, cierta ambientalización de los históricos conflictos territoriales. Utilizando materiales provenientes de un trabajo de campo etnográfico que iniciamos en 2008, presentaremos a dos familias de pobladores rurales. En ambos casos es posible ver cómo el acceso a la tierra es decisivo para las experiencias formativas en las actividades de reproducción social, y que se liga con identificaciones como "gente de la colonia" y una incipiente referencia a la "agricultura familiar" a partir de las intervenciones del Estado. Estas dos familias permiten mostrar cómo las experiencias e identificaciones se expresan en el contexto de la participación de los sujetos en conflictos sociales, que asumen en un caso la forma histórica de reclamos fundiarios mientras que, en el otro, es posible ver que el ambiente tiene protagonismo incipiente.