Modeling the Landau-gauge ghost propagator in 2, 3, and 4 spacetime dimensions

We present an analytic description of numerical results for the ghost propagator G(p(2)) in the minimal Landau gauge on the lattice. The data were produced in the SU(2) case using the largest lattice volumes to date, for d = 2, 3 and 4 spacetime dimensions. Our proposed form for G(p(2)) is derived from the one-loop relation between ghost and gluon propagators, considering a tree-level ghost-gluon vertex and our previously obtained gluon-propagator results [A. Cucchieri et al., Phys. Rev. D 85, 094513 (2012). Although this one-loop expression is not a good description of the data, it leads to a one-parameter fit of our ghost-propagator data with a generally good value of chi(2)/d.o.f., comparable to other fitting forms used in the literature. At the same time, we present a simple parametrization of the difference between the lattice data and the one-loop predictions

BRST-Symmetry Breaking and Bose-Ghost Propagator in Lattice Minimal Landau Gauge

The Bose-ghost propagator has been proposed as a carrier of the confining force in Yang-Mills theories in minimal Landau gauge. We present the first numerical evaluation of this propagator, using lattice simulations for the SU(2) gauge group in the scaling region. Our data are well described by a simple fitting function, which is compatible with an infrared-enhanced Bose-ghost propagator. This function can also be related to a massive gluon propagator in combination with an infrared-free (Faddeev-Popov) ghost propagator. Since the Bose-ghost propagator can be written as the vacuum expectation value of a BRST-exact quantity and should therefore vanish in a BRST-invariant theory, our results provide the first numerical manifestation of BRST-symmetry breaking due to restriction of gauge-configuration space to the Gribov region.Comment: 4 pages, 2 figures, 1 tabl

On the maximum bias functions of MM-estimates and constrained M-estimates of regression

We derive the maximum bias functions of the MM-estimates and the constrained M-estimates or CM-estimates of regression and compare them to the maximum bias functions of the S-estimates and the $\tau$-estimates of regression. In these comparisons, the CM-estimates tend to exhibit the most favorable bias-robustness properties. Also, under the Gaussian model, it is shown how one can construct a CM-estimate which has a smaller maximum bias function than a given S-estimate, that is, the resulting CM-estimate dominates the S-estimate in terms of maxbias and, at the same time, is considerably more efficient.Comment: Published at http://dx.doi.org/10.1214/009053606000000975 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Convergence: How Five Trends Will Reshape the Social Sector

This report highlights five key trends and how their coming together will shape the social sector of the future. Based on extensive review of existing research and in-depth interviews with thought leaders and nonprofit leaders and activists, it explores the trends (Demographic Shifts; Technological Advances; Networks Enabling Work to be Organized in New Ways; Rising Interest in Civic Engagement and Volunteerism; and Blurring of Sector Boundaries) and looks at the ways nonprofits can successfully navigate the changes. The monograph is by La Piana Consulting, a national firm dedicated to strengthening nonprofits and foundations

Relationships between horizontal force velocity profiling and starting block performance in elite sprinter athletes

Purpose: The main purpose of this study is to understand the relationship between block starting performance of elite male sprinters and their lower-body strength and power, obtained by force-velocity profile. Methods: In this cross-sectional study of thirteen male high-level sprinters (age 23.8 ± 3.1 years; height 1.82 ± 0.04 m; body mass 77.1 ± 5.5 kg; 100m PB 10.53 ± 0.26 s) tested at the National Indoor Athletics High Performance Centre for both block starting and sprinting tests at the beginning of February. The anthropometry and external force data were collected from each block using force instrumented starting blocks custom-made force platforms, were used to determine block starting performance variables such as block velocity, maximal and average horizontal force, horizontal power and normalized average horizontal power. The velocity-time data were used to determine the variables of interest of the horizontal FPV profile (F0, v0, Pmax, DRF, and RFmax) according to the Samozino's method as well as sprint time to 40 m. Pearson’s correlation coefficients (r) were used to test the relationship between dependent variables. Results: The block starting performance variables correlations with NAHP were typically moderate to nearly perfect. However, when analyzing F-V profile associated with NAHP, F0 showed no correlation with start block performance, while v0, Pmax, DRF and RFmax indicates a large to very large correlations. Conclusions: The data obtained in this study, provided a new view on the performance in the starting of blocks and initial acceleration of elite sprinters, indicating that the horizontal power plays a fundamental role in these phases of the 100m race. It should also be noted the importance of the maximum theoretical speed and the force ratio in the final sprint time and its association with the average horizontal power applied in the starting blocks. This data can help coaches to guide their athletes' training process, individualizing training stimuli and optimizing their sports performance.Objetivo: O presente estudo pretendeu analisar a relação estabelecida entre o desempenho na partida de blocos e as variáveis do perfil de força-velocidade-potência (F-V-P) dos membros inferiores em velocistas masculinos de elite. Métodos: Treze velocistas masculinos de elite (idade 23,8 ± 3,1 anos; altura 1,82 ± 0,04 m; massa corporal 77,1 ± 5,5 kg; 100m RP, 10.53 ± 0.26 s) foram testados no Complexo de Atletismo do Centro de Alto Rendimento do Jamor, tendo realizado partidas de blocos e sprints de 40 m à máxima intensidade. As forças de reação dos apoios na partida foram registadas através de blocos de partida instrumentados com plataformas de força (1000 Hz), tendo permitido a determinação de variáveis de desempenho na partida de blocos (velocidade na partida, força horizontal máxima e média, potência horizontal máxima e media, e potência horizontal média normalizada). Os dados de velocidade-tempo dos sprints de 40m foram obtidos através de células fotoelétricas e usados para determinar o tempo de sprint a 40 m e as variáveis de interesse do perfil F-V-P (F0, v0, Pmax, DRF e RFmax). A relação entre as várias variáveis dependentes foi testada através de coeficientes de Pearson. Resultados: A potência horizontal média normalizada (NAHP) apresenta correlações moderadas a quase perfeitas com as restantes variáveis de desempenho na partida de blocos. No entanto, ao relacioná-la com as variáveis do perfil F-V-P, não se verificou nenhuma associação com a F0, mas relações fortes a muito fortes com a v0, Pmax, DRF e RFmax. Conclusões: Os dados obtidos neste estudo fornecem uma nova visão no desempenho na partida de blocos e fase de aceleração em velocistas de elite, indicando que a potência horizontal desempenha um papel fundamental nesta fase da corrida de 100m. De realçar ainda a importância da velocidade máxima teórica e do rácio de força no tempo final de sprint e a sua associação com a potência horizontal média aplicada nos blocos de partida. Estes dados podem auxiliar treinadores a orientar o processo de treino dos seus atletas, individualizando os estímulos de treino e otimizando o respetivo desempenho desportivo

How employee portal contributes for the intangible assets value creation

Today's increasingly business competition and the information technologies development led to huge corporate organisational changes and pulled intangible assets up in the value chain. Employees’ skills, talent and know how, intellectual property, information, information systems, infrastructure, culture, teamwork capacity and other forms of non-physical assets are critical sources of value. But in order to generate value they must be integrated with each other and aligned with the objectives for the internal processes. To address some organisation concerns related to value creation and change management, a theoretical multi-tier framework was developed. This framework illustrates the path and flows of value-creation, the relationships between “intangible assets” and the representation of “enabling changes projects”. Strategy Map and Benefits Dependency Network were combined, resulting in a stronger framework to help organizations enhancing their strategy knowledge, to reduce the risk of projects failure, and to capture real value from their investments. In order to understand how an employee portal contributes for the intangible assets value creation process, an Employee Portal case study was carried out. The author performed a preliminary study comprising a literature review and data collection followed with semi-structured interviews and analysis of employee satisfaction surveys results to triangulate and confirm all the data gathered.O aumento da competitividade empresarial aliado ao nível de desenvolvimento das tecnologias de informação provocou enormes mudanças organizacionais e aumentou a importância dos ativos intangíveis na cadeia de valor. As competências, talento e o “saber fazer” dos colaboradores, a propriedade intelectual, informação, sistemas de informação, infraestrutura, cultura organizacional, capacidade de trabalho em equipa e outras formas de ativos intangíveis são fontes importantes de valor. Contudo para gerarem valor, estes ativos devem estar integrados entre si e alinhados com os objetivos para os processos internos. Para endereçar algumas preocupações, da organização, relacionadas com a criação de valor e com a gestão da mudança, desenvolvemos um modelo teórico com estrutura multicamada. Este modelo ilustra os caminhos e os fluxos de criação de valor, as relações entre os "ativos intangíveis" e a representação dos "facilitadores de mudança". Combinámos o Mapa Estratégico e a rede de dependência de benefícios, resultando num modelo mais robusto para ajudar as organizações a melhorar o conhecimento da estratégia, reduzindo o risco de falha de projetos e captando o valor real de seus investimentos. Por forma a entender a forma como um portal de colaborador contribui para o processo de criação de valor dos ativos intangíveis da empresa, foi realizado um estudo de caso com um portal de colaborador. O autor realizou um estudo preliminar que compreende a revisão da literatura e coleta de dados, seguida por entrevistas semiestruturadas e análise dos resultados de questionários de satisfação de colaboradores para triangulação e confirmação dos dados recolhidos

The Photographic Ateliers of Carlos Relvas

Photography studies have not always been dedicated to the analysis of photographic studios to better understand the works of great photographers. This essay focuses on the different photographic studios of Carlos Relvas (1838-1894) in Golegã, with a particular focus on the little-studied and littleknown transformations of his splendorous Photographic Atelier of Golegã into a residential space. In the 1870s, the paradigm shift of photosensitive emulsions to faster exposure times had an impact on the way Carlos Relvas looked at his studio, forcing him to rethink the investment made in a space that no longer corresponded to the new technical reality of photography. Understood as a light production machine, Carlos Relvas’ studio is a key piece in his photographic work. In this essay, through the analysis of his photographs, we recover details and aspects of his various studios that are revealing of his inventive spirit, as well as his desire to keep up with the evolution of photographic art.&nbsp