261 research outputs found
Recent Advances in the Application of the Shell Model Monte Carlo Approach to Nuclei
The shell model Monte Carlo (SMMC) method is a powerful technique for
calculating the statistical and collective properties of nuclei in the presence
of correlations in model spaces that are many orders of magnitude larger than
those that can be treated by conventional diagonalization methods. We review
recent advances in the development and application of SMMC to mid-mass and
heavy nuclei.Comment: 6 pages, 5 figures, Proceedings of the Eleventh International Spring
Seminar on Nuclear Physic
The importance of comparative phylogeography in diagnosing introduced species: a lesson from the seal salamander, Desmognathus monticola
<p>Abstract</p> <p>Background</p> <p>In most regions of the world human influences on the distribution of flora and fauna predate complete biotic surveys. In some cases this challenges our ability to discriminate native from introduced species. This distinction is particularly critical for isolated populations, because relicts of native species may need to be conserved, whereas introduced species may require immediate eradication. Recently an isolated population of seal salamanders, <it>Desmognathus monticola</it>, was discovered on the Ozark Plateau, ~700 km west of its broad continuous distribution in the Appalachian Mountains of eastern North America. Using Nested Clade Analysis (NCA) we test whether the Ozark isolate results from population fragmentation (a natural relict) or long distance dispersal (a human-mediated introduction).</p> <p>Results</p> <p>Despite its broad distribution in the Appalachian Mountains, the primary haplotype diversity of <it>D. monticola </it>is restricted to less than 2.5% of the distribution in the extreme southern Appalachians, where genetic diversity is high for other co-distributed species. By intensively sampling this genetically diverse region we located haplotypes identical to the Ozark isolate. Nested Clade Analysis supports the hypothesis that the Ozark population was introduced, but it was necessary to include haplotypes that are less than or equal to 0.733% divergent from the Ozark population in order to arrive at this conclusion. These critical haplotypes only occur in < 1.2% of the native distribution and NCA excluding them suggest that the Ozark population is a natural relict.</p> <p>Conclusion</p> <p>Our analyses suggest that the isolated population of <it>D. monticola </it>from the Ozarks is not native to the region and may need to be extirpated rather than conserved, particularly because of its potential negative impacts on endemic Ozark stream salamander communities. Diagnosing a species as introduced may require locating nearly identical haplotypes in the known native distribution, which may be a major undertaking. Our study demonstrates the importance of considering comparative phylogeographic information for locating critical haplotypes when distinguishing native from introduced species.</p
Dimensionamento amostral para estimação de coeficientes de correlação em híbridos de milho, safras e níveis de precisão
Effect of a Successful Intensive Lifestyle Program on Insulin Sensitivity and Glucose Tolerance in Obese Youth
OBJECTIVE—To evaluate the impact on glucose metabolism of a lifestyle program (the Yale Bright Bodies Program) for obese children
Endomárketing: Estrategia de innovación en las organizaciones el siglo XXI
Productivity, profitability and good organizational
climate are the challenges that companies, regardless
of their size, assume in this century. The permanent
competitiveness has generated a tight business
environment in the level of internal gear of the
company is reflected in the positioning of the product
or service that offers the same to the end customer.
This is why managing to the interior of companies has
taken on a role in generating innovative processes
such as Endomarketing. This is a series of techniques
directed and applied to the internal customers
(employees) that create the permanent motivation
towards the accomplishment of their daily tasks, the
commitment and the end of the organization, to make
the worker the first client, in the more faithful and
The best reference that the final customer can find.
This article proposes that Endomarketing is an
effective strategy to improve organizational
processes, internal customer satisfaction and business
projection.Productividad, rentabilidad y buen clima
organizacional son los retos que las empresas, sin
importar su tamaño, asumen en este siglo. La
competitividad permanente ha generado un ambiente
empresarial reñido donde el nivel de engranaje
interno de la empresa se refleja en el posicionamiento
del producto o servicio que ofrece la misma al cliente
final. Es por ello gestionar hacia el interior de las
empresas ha tomado relevancia generando procesos
innovadores como el Endomárketing. Este es una
serie de técnicas dirigidas y aplicadas a los clientes
internos (empleados) que crea motivación
permanente hacia la realización de sus labores
diarias, compromiso y lealtad con la organización,
para lograr que el trabajador sea el primer cliente, en
el más fiel y la mejor referencia que el cliente final
pueda encontrar. Este artículo plantea que es el
Endomárketing una estrategia eficaz para mejorar los
procesos organizacionales, la satisfacción de los
clientes internos y la proyección empresarial
High-precision excited state lifetime measurements in rare earth nuclei using LaBr3(Ce) detectors
To study how collective nuclear structure evolves towards mid-shell and test next-generation LaBr3(Ce) scintillation detectors, measurements of the lifetimes of 2+ 1 states in 168Hf and 174W were conducted at the Wright Nuclear Structure Laboratory. Prel
Evolution of collectivity near mid-shell from excited-state lifetime measurements in rare earth nuclei
The B(E2) excitation strength of the first excited 2+ state in even-even nuclei should directly correlate with the size of the valence space and maximize at mid-shell. A previously found saturation of B(E2) strengths in well-deformed rotors at mid-shell is tested through high-precision measurements of the lifetimes of the lowest-lying 2+ states of the Hf168 and W174 rare earth isotopes. Measurements were performed using fast LaBr3 scintillation detectors. Combined with the recently remeasured B(E2;2+1→0+1) values for Hf and W isotopes the new data remove discrepancies observed in the differentials of B(E2) values for these isotope
Ensayos cuasi-estáticos cíclicos de muros delgados de concreto reforzado en edificios colombianos
The use of thin reinforced concrete walls (thickness of 8 to 12 cm) in Latin America has become a popular building construction practice in the last two decades. Several existing studies indicate that the inelastic deformation capacity could be limited and the level of damage could be severe even at low levels of plastic rotation. There is a lack of experimental data and practically no field post-earthquake observations related to the behavior of this construction system; therefore, a research effort was recently launched to gather further information about the geometry, materials, reinforcement detailing and response of these thin RC walls. The main variables of interest indentified during the early stage of the study were the slenderness ratio, axial load ratio, reinforcement detailing, and cross section geometry. Based on such study, several prototypes have been defined for experimental testing. This paper presents the preliminary results of a T-shaped single layer reinforced concrete wall with a shear span ratio of 2. The reinforcement comprises ductile conventional steel bars, with not additional steel at the web boundary. A reversed cyclic load pattern was applied to the specimen, keeping an axial load ratio of 5% based on the specified concrete compressive strength. The results obtained indicated a limited capacity of inelastic deformation, reaching an average plastic rotation of 0.75% before flexural traction failure, followed by concrete crushing during a posterior cycle
Rural factors and survival from cancer: analysis of Scottish cancer registrations
In this survival study 63 976 patients diagnosed with one of six common cancers in Scotland were followed up. Increasing distance from a cancer centre was associated with less chance of diagnosis before death for stomach, breast and colorectal cancers and poorer survival after diagnosis for prostate and lung cancers. © 2000 Cancer Research Campaig
Interval estimation and optimal design for the within-subject coefficient of variation for continuous and binary variables
BACKGROUND: In this paper we propose the use of the within-subject coefficient of variation as an index of a measurement's reliability. For continuous variables and based on its maximum likelihood estimation we derive a variance-stabilizing transformation and discuss confidence interval construction within the framework of a one-way random effects model. We investigate sample size requirements for the within-subject coefficient of variation for continuous and binary variables. METHODS: We investigate the validity of the approximate normal confidence interval by Monte Carlo simulations. In designing a reliability study, a crucial issue is the balance between the number of subjects to be recruited and the number of repeated measurements per subject. We discuss efficiency of estimation and cost considerations for the optimal allocation of the sample resources. The approach is illustrated by an example on Magnetic Resonance Imaging (MRI). We also discuss the issue of sample size estimation for dichotomous responses with two examples. RESULTS: For the continuous variable we found that the variance stabilizing transformation improves the asymptotic coverage probabilities on the within-subject coefficient of variation for the continuous variable. The maximum like estimation and sample size estimation based on pre-specified width of confidence interval are novel contribution to the literature for the binary variable. CONCLUSION: Using the sample size formulas, we hope to help clinical epidemiologists and practicing statisticians to efficiently design reliability studies using the within-subject coefficient of variation, whether the variable of interest is continuous or binary
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