18,768 research outputs found

    Letter from the Editors

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    The Gettysburg Historical Journal embodies the History Department’s dedication to diverse learning and excellence in academics. Each year, the Journal publishes the top student work in a range of topics across the spectrum of academic disciplines with different methodological approaches to the study of history. In the words of Marc Bloch, author of The Historian’s Craft, “history is neither watchmaking nor cabinet construction. It is an endeavor toward better understanding.” In the spirit of this maxim, our authors strive to elucidate the many facets of human societies and cultures. Whether these young scholars’ research is focused on politics, religion, economics, environmental history, or women gender and sexuality studies, the editorial staff is consistently proud of the diverse subject matter we select for publication. [excerpt

    Discrete Dynamical Systems: A Brief Survey

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    Dynamical system is a mathematical formalization for any fixed rule that is described in time dependent fashion. The time can be measured by either of the number systems - integers, real numbers, complex numbers. A discrete dynamical system is a dynamical system whose state evolves over a state space in discrete time steps according to a fixed rule. This brief survey paper is concerned with the part of the work done by José Sousa Ramos [2] and some of his research students. We present the general theory of discrete dynamical systems and present results from applications to geometry, graph theory and synchronization

    Competing order and nature of the pairing state in the iron pnictides

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    We show that the competition between magnetism and superconductivity can be used to determine the pairing state in the iron arsenides. To this end we demonstrate that the itinerant antiferromagnetic phase (AFM) and the unconventional s+s^{+-} sign-changing superconducting state (SC) are near the borderline of microscopic coexistence and macroscopic phase separation, explaining the experimentally observed competition of both ordered states. In contrast, conventional s++s^{++} pairing is not able to coexist with magnetism. Expanding the microscopic free energy of the system with competing orders around the multicritical point, we find that static magnetism plays the role of an intrinsic interband Josephson coupling, making the phase diagram sensitive to the symmetry of the Cooper pair wavefunction. We relate this result to the quasiparticle excitation spectrum and to the emergent SO(5)(5) symmetry of systems with particle-hole symmetry. Our results rely on the assumption that the same electrons that form the ordered moment contribute to the superconducting condensate and that the system is close to particle-hole symmetry. We also compare the suppression of SC in different regions of the FeAs phase diagram, showing that while in the underdoped side it is due to the competition with AFM, in the overdoped side it is related to the disappearance of pockets from the Fermi surface.Comment: 24 pages, 13 figures; revised versio

    Variação da produtividade do arroz de terras altas influenciados pela seca meteorológica em Goiás.

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    A seca é um fenômeno meteorológico caracterizado pela falta de precipitação pluvial, que pode causar grandes prejuízos à produção agrícola. O presente trabalho tem como objetivo caracterizar a ocorrência de seca, utilizando o Índice Padronizado de Precipitação (SPI) em cinco microrregiões do estado de Goiás e sua influencia na produtividade de arroz de terras altas. As cinco microrregiões estudadas foram: Anápolis, Ceres, Iporá, Anicuns e Goiânia. A série de dados históricos de precipitação foi disponibilizada pela Agência Nacional de Águas (ANA), coletados em um município pertencente à microrregião analisada. O período de estudo foi de 1975 a 2005. Os dados de produtividade, para o mesmo período foi disponibilizado pela AGROTEC. Os valores do SPI foram caracterizados pela a ocorrência dos eventos de seca, frequência relativa, comparação com os dados de produtividade do arroz de terras altas e o percentual de acerto do índice. Foi possível observar que o SPI não acompanhou totalmente a variação da produtividade do arroz de terras altas. O SPI apresentou percentuais de acerto baixos, em todas as microrregiões, ficando próximo a 51%

    A self-assessment tool for social responsibility in higher education. Reporting on a national policy development process in Portugal

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    Purpose Providing higher education institutions (HEIs) with a tool for self-assessing their social responsibility (SR) that generates the information and knowledge necessary to a strategic approach to adopting the Green Paper recommendations about the SR of HEIs. Setting out the collaborative policy development process to construct the tool “Indicators of SR of HEIs” (ISRHEI). Design/methodology/approach After a literature review, including self-assessment (SA) tools and leading guidelines, a working group of 24 Portuguese HEIs was created to co-construct the ISRHEI tool, which was then subject to validation in a pilot study. Findings There are 34 indicators in the ISRHEI tool, structured by sequential levels according to the HEI alignment with SR (policies, procedures, practices and monitoring along a strategic continuum) hoping to achieve impacts on the organisational, educational, cognitive and social level. Originality/value This is an innovative and national policy development process for SR in Portugal. It gives insights into guiding documents, SA indicators for SR and the process of developing consensus on this topic amongst 24 HEIs in Portugal. The ISRHEI tool is tailored to the specific characteristics and level of development of HEIs.info:eu-repo/semantics/acceptedVersio

    Probing the ejecta of evolved massive stars in transition: A VLT/SINFONI K-band survey

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    Massive evolved stars in transition phases, such as Luminous Blue Variables (LBVs), B[e] Supergiants (B[e]SGs), and Yellow Hypergiants (YHGs), are not well understood, and yet crucial steps in determining accurate stellar and galactic evolution models. The circumstellar environments of these stars reveal their mass-loss history, identifying clues to both their individual evolutionary status and the connection between objects of different phases. Here we present a survey of 25 such evolved massive stars (16 B[e]SGs, 6 LBVs, 2 YHGs, and 1 Peculiar Oe star), observed in the K-band with the Spectrograph for INtegral Field Observation in the Near-Infrared (SINFONI; R = 4500) on the ESO VLT UT4 8 m telescope. The sample can be split into two categories based on spectral morphology: one group includes all of the B[e]SGs, the Peculiar Oe star, and two of the LBVs, while the other includes the YHGs and the rest of the LBVs. The difference in LBV spectral appearance is due to some objects being in a quiescent phase and some objects being in an active or outburst phase. CO emission features are found in 13 of our targets, with first time detections for MWC 137, LHA 120-S 35, and LHA 115-S 65. From model fits to the CO band heads, the emitting regions appear to be detached from the stellar surface. Each star with ^12CO features also shows ^13CO emission, signaling an evolved nature. Based on the level of ^13C enrichment, we conclude that many of the B[e]SGs are likely in a pre-Red Supergiant phase of their evolution. There appears to be a lower luminosity limit of log L/L_solar = 5.0 below which CO is not detected. The lack of CO features in several high luminosity B[e]SGs and variability in others suggests that they may in fact be LBV candidates, strengthening the connection between these two very similar transition phases.Comment: 20 pages, 13 figures, 7 tables. Accepted for publication in A&

    Electronic governance in Portugal: a silent pioneer

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    This paper sums up the Portuguese experience on launching and implementing a number of successful EGOV policies at different levels. Such a success was based on a holistic understanding of EGOV, in the confluence of technology, administrative reform and innovation processes, and enforced through a number of well- defined, consistent policies carried out over time. The role of national agencies, independent from local political instances and private interests, in the implementation of an effective EGOV strategy is also stressed.(undefined

    The complexity of neuropsychiatric manifestations of COVID-19 in South Africa

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    SARS-CoV-2 was first identified in Wuhan City, China, in 2019. Initially it was associated with the development of pulmonary disease, but research over the past 2 years has identified effects on multiple systems. Neuropsychiatric manifestations of COVID-19 have been reported in countries around the world, including new-onset psychosis in patients with no personal or family psychiatric history. We present the first case series describing neuropsychiatric manifestations of patients in Johannesburg, South Africa (SA). All four patients presented with their index-episode psychosis, and evidence of COVID-19 infection. The patients had varied psychiatric presentations, from delirium and psychosis to mania, and all responded well to low doses of antipsychotics. One patient had newly diagnosed HIV in addition to COVID-19. Further research is needed to determine the prevalence of neuropsychiatric manifestations in acute SARS-CoV-2 infections in SA

    Serum Cytokine Levels In Autoimmune And Non-autoimmune Hyperthyroid States.

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    Although the role of interleukin-2 (IL-2) and interferon gamma (gammaIFN) is still poorly understood in hyperthyroid diseases, it is reasonable to assume that these cytokines may be present at higher levels in Graves' disease (GD) than in other primarily non-autoimmune thyroid diseases. In order to look for an easy method to distinguish GD from primarily non-autoimmune causes of hyperthyroidism, we compared 13 healthy individuals with 21 treated and untreated hyperthyroid GD patients and with 19 patients with hyperthyroidism due to other etiologies: 7 cases of multinodular goiter, 5 cases of excessive hormone replacement and 7 cases of amiodarone-associated hyperthyroidism. All patients presented low TSH levels and a dubious clinical thyroid state. We found a good correlation between TSH and serum IL-2 levels (r = 0.56; P<0.01). Serum IL-2 (P<0.01) and gammaIFN (P<0.01) levels were lower in the hyperthyroid group of patients than in control subjects, suggesting a depressed TH1 pattern in the T-cell subset of hyperthyroid patients. GD had normal IL-2 levels, while patients with other forms of thyrotoxicosis presented decreased IL-2 levels (P<0.05). There was no difference between treated and untreated GD patients. We suggest that the direct measurement of serum IL-2 level may help to confirm hyperthyroidism caused by GD.3365-
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