2,064 research outputs found

    Self-organized evolution in socio-economic environments

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    We propose a general scenario to analyze social and economic changes in modern environments. We illustrate the ideas with a model that incorporating the main trends is simple enough to extract analytical results and, at the same time, sufficiently complex to display a rich dynamic behavior. Our study shows that there exists a macroscopic observable that is maximized in a regime where the system is critical, in the sense that the distribution of events follow power-laws. Computer simulations show that, in addition, the system always self-organizes to achieve the optimal performance in the stationary state.Comment: 4 pages RevTeX; needs epsf.sty and rotate.sty; submitted to Phys Rev Let

    Synthesis and Biological Evaluation As Microtubule-Active Agents of Several Tetrahydrofuran and Spiroacetal Derivatives

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    The stereoselective preparation of several molecules containing structural fragments of the tetrahydrofuran and spiroacetal type is described. Their degree of cytotoxicity and their interactions with tubulin have been investigated. It has been confirmed that the tetrahydrofuran derivatives are cytotoxic but, in contrast to previous reports, it has been found that the cytoxicity is not due to interactions with the microtubule network. Furthermore, and also in contrast to a previous report on closely related compounds, the spiroacetal derivatives do show interactions with tubulin, even though the precise mechanism and the binding site still remain to be established

    Angiolymphoid hyperplasia with eosinophilia: efficacy of isotretinoin?

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    BACKGROUND: Angiolymphoid hyperplasia with eosinophilia (ALHE) is a benign but potentially disfiguring vascular lesion. It is usually characterized by dermal and subcutaneous nodules, primarily in the head and neck region. Spontaneous regression is common, but persistent or recurrent lesions may require treatment. Several treatments have been reported but surgery is the most efficient one. METHODS AND RESULTS: We report a 32-year-old man presenting with multiple nodules on the cheeks, preauricular region and the scalp and who received treatment with isotretinoin (0.5 mg/kg/day) for 1 year with complete resolution of one of his scalp nodules. The rest of the lesions remained stable and were treated with surgical excision without recurrence. CONCLUSION: Isotretinoin may play a role in the treatment of ALHE due to its antiangiogenic properties via a reduction of vascular endothelial growth factor (VEGF) production by keratinocytes

    Lifestyle and comorbid conditions as risk factors for community-acquired pneumonia in outpatient adults (NEUMO-ES-RISK project)

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    Introduction: Information about community-acquired pneumonia (CAP) risk in primary care is limited. We assess different lifestyle and comorbid conditions as risk factors (RF) for CAP in adults in primary care. Methods: A retrospective-observational-controlled study was designed. Adult CAP cases diagnosed at primary care in Spain between 2009 and 2013 were retrieved using the National Surveillance System of Primary Care Data (BiFAP). Age-matched and sex-matched controls were selected by incidence density sampling (ratio 2:1). Associations are presented as percentages and OR. Binomial regression models were constructed to avoid bias effects. Results: 51 139 patients and 102 372 controls were compared. Mean age (SD) was 61.4 (19.9) years. RF more significantly linked to CAP were: HIV (OR [95% CI]: 5.21 [4.35 to 6.27]), chronic obstructive pulmonary disease (COPD) (2.97 [2.84 to 3.12]), asthma (2.16 [2.07,2.26]), smoking (1.96 [1.91 to 2.02]) and poor dental hygiene (1.45 [1.41 to 1.49]). Average prevalence of any RF was 82.2% in cases and 69.2% in controls (2.05 [2.00 to 2.10]). CAP rate increased with the accumulation of RF and age: risk associated with 1RF was 1.42 (1.37 to 1.47) in 18-60-year-old individuals vs 1.57 (1.49 to 1.66) in >60 years of age, with 2RF 1.88 (1.80 to 1.97) vs 2.35 (2.23, 2.48) and with >/= 3 RF 3.11 (2.95, 3.30) vs 4.34 (4.13 to 4.57). Discussion: Prevalence of RF in adult CAP in primary care is high. Main RFs associated are HIV, COPD, asthma, smoking and poor dental hygiene. Our risk stacking results could help clinicians identify patients at higher risk of pneumonia

    Phytochemicals as antibiotic alternatives to promote growth and enhance host health

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    There are heightened concerns globally on emerging drug-resistant superbugs and the lack of new antibiotics for treating human and animal diseases. For the agricultural industry, there is an urgent need to develop strategies to replace antibiotics for food-producing animals, especially poultry and livestock. The 2nd International Symposium on Alternatives to Antibiotics was held at the World Organization for Animal Health in Paris, France, December 12-15, 2016 to discuss recent scientific developments on strategic antibiotic-free management plans, to evaluate regional differences in policies regarding the reduction of antibiotics in animal agriculture and to develop antibiotic alternatives to combat the global increase in antibiotic resistance. More than 270 participants from academia, government research institutions, regulatory agencies, and private animal industries from >25 different countries came together to discuss recent research and promising novel technologies that could provide alternatives to antibiotics for use in animal health and production; assess challenges associated with their commercialization; and devise actionable strategies to facilitate the development of alternatives to antibiotic growth promoters (AGPs) without hampering animal production. The 3-day meeting consisted of four scientific sessions including vaccines, microbial products, phytochemicals, immune-related products, and innovative drugs, chemicals and enzymes, followed by the last session on regulation and funding. Each session was followed by an expert panel discussion that included industry representatives and session speakers. The session on phytochemicals included talks describing recent research achievements, with examples of successful agricultural use of various phytochemicals as antibiotic alternatives and their mode of action in major agricultural animals (poultry, swine and ruminants). Scientists from industry and academia and government research institutes shared their experience in developing and applying potential antibiotic-alternative phytochemicals commercially to reduce AGPs and to develop a sustainable animal production system in the absence of antibiotics.Fil: Lillehoj, Hyun. United States Department of Agriculture. Agricultural Research Service; ArgentinaFil: Liu, Yanhong. University of California; Estados UnidosFil: Calsamiglia, Sergio. Universitat AutĂČnoma de Barcelona; EspañaFil: Fernandez Miyakawa, Mariano Enrique. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentina. Instituto Nacional de TecnologĂ­a Agropecuaria. Centro de InvestigaciĂłn en Ciencias Veterinarias y AgronĂłmicas. Instituto de PatobiologĂ­a; ArgentinaFil: Chi, Fang. Amlan International; Estados UnidosFil: Cravens, Ron L.. Amlan International; Estados UnidosFil: Oh, Sungtaek. United States Department of Agriculture. Agricultural Research Service; ArgentinaFil: Gay, Cyril G.. United States Department of Agriculture. Agricultural Research Service; Argentin

    Operations of and Future Plans for the Pierre Auger Observatory

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    Technical reports on operations and features of the Pierre Auger Observatory, including ongoing and planned enhancements and the status of the future northern hemisphere portion of the Observatory. Contributions to the 31st International Cosmic Ray Conference, Lodz, Poland, July 2009.Comment: Contributions to the 31st ICRC, Lodz, Poland, July 200

    Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV

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    We describe the measurement of the depth of maximum, Xmax, of the longitudinal development of air showers induced by cosmic rays. Almost four thousand events above 10^18 eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106 +35/-21) g/cm^2/decade below 10^(18.24 +/- 0.05) eV and (24 +/- 3) g/cm^2/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm^2. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.Comment: Accepted for publication by PR

    Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory

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    The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies E>Eth=5.5×1019E>E_{th}=5.5\times 10^{19} eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at E>EthE>E_{th} are heavy nuclei with charge ZZ, the proton component of the sources should lead to excesses in the same regions at energies E/ZE/Z. We here report the lack of anisotropies in these directions at energies above Eth/ZE_{th}/Z (for illustrative values of Z=6, 13, 26Z=6,\ 13,\ 26). If the anisotropies above EthE_{th} are due to nuclei with charge ZZ, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies
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