A pure S-wave covariant model for the nucleon

Using the manifestly covariant spectator theory, and modeling the nucleon as a system of three constituent quarks with their own electromagnetic structure, we show that all four nucleon electromagnetic form factors can be very well described by a manifestly covariant nucleon wave function with zero orbital angular momentum. Since the concept of wave function depends on the formalism, the conclusions of light-cone theory requiring nonzero angular momentum components are not inconsistent with our results. We also show that our model gives a qualitatively correct description of deep inelastic scattering, unifying the phenomenology at high and low momentum transfer. Finally we review two different definitions of nuclear shape and show that the nucleon is spherical in this model, regardless of how shape is defined.Comment: 20 pages and 10 figures; greatly expanded version with new fits and discussion of DIS; similar to published versio

Covariant nucleon wave function with S, D, and P-state components

Expressions for the nucleon wave functions in the covariant spectator theory (CST) are derived. The nucleon is described as a system with a off-mass-shell constituent quark, free to interact with an external probe, and two spectator constituent quarks on their mass shell. Integrating over the internal momentum of the on-mass-shell quark pair allows us to derive an effective nucleon wave function that can be written only in terms of the quark and diquark (quark-pair) variables. The derived nucleon wave function includes contributions from S, P and D-waves.Comment: 13 pages and 1 figur

The bright side of the dark side: covert politics as an alternative to the negative impacts of coercive change

This study examines practitioners as individual actors by focusing on a general manager's individual account. With a two-week episode of political maneuvering as a starting point, the case shows how skilful strategizing on the part of the general manager is at the origin of significant organizational change. Specifically, the paper has three purposes. First, to offer insights to practitioners and scholars regarding how powerful managers purposefully seek to influence organizational context in a non-disclosed fashion. Second, to illustrate how single case microstudies open a route to understanding events that would otherwise be unattainable. The third, and most important, is to apply organizational politics concepts to characterize managerial covert political action in the implementation of a deliberate strategy. Specifically, emphasis is put on how contextual characteristics relate to political action. How they constrain and enable politics, and facilitate the use and maintenance of concealed motives

A Female Pharaoh and The Emperor’s Wife: Hatshepsut, Julia Domna, and Female Authority in Antiquity

This thesis analyzes how historical notions of masculinity and femininity shaped perceptions of power between the Egyptian female pharaoh Hatshepsut and Roman empress Julia Domna. Both rulers carefully created visual narratives of masculinity and femininity to leverage respect from their citizens, in accordance with what was contextually appropriate for their respective societies. It will be shown that there are blatant disconnects between how others perceived them and how they wished to be portrayed. Hatshepsut, a rare female pharaoh, depicted herself in the regalia of a male king with a false ceremonial beard, scepters and crowns. Domna was described as the masculine counterpart to her effeminate co-ruler son Caracalla, acting as a vengeful matriarch, driven by power. She is visually portrayed, however, as the ideal matron, embodying virtues of fertility, piety and modesty. To contextualize the disconnect, historical accounts by ancient historians (Roman History and the Historia Augusta) as well as material culture consisting of reliefs, statues, coinage and monumental arches (based on imagery of which both Hatshepsut and Domna would have approved) will be considered. Both women also leveraged their relationships to their families, predecessors and various divinities to emphasize the legitimacy of their regimes. It is within these scenes, that their unique gender expressions are particularly evident through the sheer quantity of their visual representations and the way they were portrayed

About the efficiency behavior of the Portuguese manufacturing firms during the financial crisis

This work studies some effects of the World Financial Crisis on firms in terms of efficiency scores, by measuring how 23K units used inputs and produced outputs, obtained from a set of Portuguese manufacturing firms on three time periods: pre-crisis (2006-2008), pretroika (2009-2011) and troika (2012-2013). We adopt a non-parametric approach, which combines Multidirectional Efficiency Analysis (MEA) with other techniques as cluster analysis, principal component analysis and dimensionality testing, to examine three empirical hypotheses: H(1) the performance of the portuguese firms in the manufacturing sector has been adversely affected by the financial crisis felt in Portugal in the troika years; H(2) due to the financial crisis, the manufacturing sector acquired long-term debt deliberately; and H(3) the financial crisis has affected substantially the food subsector. The results indicate that H(1) is confirmed, but not totally, H(2) is confirmed and H(3) is rejected. We also found surprisingly good affine fittings between inputs and capital, and outputs and EBIT with really good p-values. Hence, we also propose a reduction of the dimensionality of the MEA model, when it is possible to apply model fitting. If the reduction results in one input and one output, we give procedures to visualize and compare between efficiencies scores.info:eu-repo/semantics/publishedVersio

On the use of hedonic regression models to measure the effect of energy efficiency on residential property transaction prices : evidence for Portugal and selected data issues

Using a unique dataset containing information of around 256 thousand residential property sales, this paper discloses a clear sales premium for most energy efficient dwellings, which is more pronounced for apartments (13%) than for houses (5 to 6%). Cross-country comparisons support the finding that energy efficiency price premiums are higher in the Portuguese residential market than in central and northern European markets. Results emphasize the relevance of data issues in hedonic regression models. They illustrate how the use of appraisal prices, explanatory variables with measurement errors, and the omission of variables associated with the quality of the properties, may seriously bias energy efficiency partial effect estimates. These findings provide valuable information not only to policy-makers, but also to researchers interested in this area.info:eu-repo/semantics/publishedVersio

Fatores Preditivos do Stress Parental

Criar um filho é um desafio de grande responsabilidade e exige profundas transformações e adaptações na vida dos pais, sendo que os comportamentos parentais são influenciados por causas múltiplas, nomeadamente o stress parental, as variáveis sociodemográficas tais como o estatuto socioeconómico, o número de filhos, o género e idade dos pais, entre muitos outros. Esta pesquisa visa conhecer as características sociodemográficas e laborais dos pais das crianças que frequentam o 2º ciclo do Colégio João de Barros, conhecer as características sociodemográficas e escolares das crianças que frequentam o 2º ciclo do Colégio João de Barros e avaliar o nível de stress parental dos pais das crianças que frequentam o 2º ciclo do Colégio João de Barros. Para além destes objetivos, pretende-se também determinar a relação existente entre o nível de stress parental dos pais das crianças que frequentam o 2º ciclo do Colégio João de Barros e algumas características sociodemográficas e laborais e determinar a relação existente entre o nível de stress parental dos pais das crianças que frequentam o 2º ciclo do Colégio João de Barros e algumas características sociodemográficas e escolares das crianças que frequentam o 2º ciclo do Colégio João de Barros. A amostra é constituida por 50 encarregados de educação e 50 crianças a frequentarem o 2º ciclo do Colégio João de Barros. Foram definidos dois grupos de amostra e para cada grupo foi utilizado um instrumento de colheita de dados. Para o grupo dos encarregados de educação, aplicou-se um questionário sociodemográfico e laboral para avaliar as características sociais e laborais dos encarregados de educação das crianças e a “Escala de Stress Parental” para avaliar os níveis de stress experimentado pelos pais. Relativamente às crianças, aplicou-se um questionário relativo a dados sociodemográficos e escolares. Os resultados revelaram baixos níveis de stress parental, assim como a não existência de relação estatisticamente significativa entre os níveis de stress parental e as características sociodemográficas e laborais recolhidas, tal como algumas características sociodemográficas e escolares relativamente às crianças. No entanto surgiram resultados interessantes, nomeadamente a relação existente entre os rendimentos dos pais e os níveis de preocupações parentais e a relação existente entre a inexistência de irmãos e os elevados níveis de falta de controlo

Annual survival rate of tropical stingless bee colonies (Meliponini): variation among habitats at the landscape scale in the Brazilian Atlantic Forest

Stingless social bees live in perennial colonies whose longevity is influenced by various ecological factors. This study analyzed the influence of habitat anthropization and native forest regeneration stage on the longevity of natural colonies at the landscape scale. Random sampling of 25x25m plots, totaling 30ha per habitat type, located and monitored 118 nests of 14 species in the forest and 105 nests of six species in the anthropic habitat. Significant differences in colony longevity were observed between young and long-lived forests  and between long-lived forests and anthropized habitat. Shorter longevities have generally been associated with a set of smaller-bodied species residing in anthropized habitats. The greatest longevities were associated with the three abundant and exclusive forest species, and was similar in the two forest regeneration stages: Melipona scutellaris, Scaptotrigona xanthotricha and Scaptotrigona bipunctata had high annual survival rates ranging from 87% to 93%. Another abundant species in the landscape was Tetragonisca angustula, a small habitat-generalist with short longevity (63%) that varied among habitats. Euclidean distance analysis based on this generalist placed young forest closest to anthropic habitat, and grouped the replicates of long-lived forest. Considering spatial variation in the life history traits, we infer that, among prospective landscape habitats, the Atlantic Forest favors stingless bees with high colonial longevity. On the other hand, generalists, such as T. angustula, with shorter colonial longevity and high reproduction rates are being favored by the expansion of anthropized habitats in place of deforested areas