1,645 research outputs found

    Intracultural diversity in a model of social dynamics

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    We study the consequences of introducing individual nonconformity in social interactions, based on Axelrod's model for the dissemination of culture. A constraint on the number of situations in which interaction may take place is introduced in order to lift the unavoidable ho mogeneity present in the final configurations arising in Axelrod's related models. The inclusion of this constraint leads to the occurrence of complex patterns of intracultural diversity whose statistical properties and spatial distribution are characterized by means of the concepts of cultural affinity and cultural cli ne. It is found that the relevant quantity that determines the properties of intracultural diversity is given by the fraction of cultural features that characterizes the cultural nonconformity of individuals.Comment: 7 pages, 2 tables, 6 figure

    Osteosarcoma de tipo compuesto: relato de caso

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      Osteosarcoma is considered the most common bone tumor in dogs, usually affecting the appendicular skeleton of animals adults or seniors with an average age of seven years. The etiology of canine appendicular osteosarcoma remains unknown. Some factors predispose the animals to the emergence of neoplasia, including: size, race and family. The tumor can be classified by macroscopic and radiological features in simple, compound, or pleomorphic. This article is a case report of osteosarcoma of the composite type with metastases in the pericardium, lung, pleura, intercostal muscles, liver and kidney in a dog breed Labrador Retriver. This presents the history of the animal, which together with the necropsy findings and histopathological examination confirmed the cause of death. We conclude that histopathological examination is an important tool for classify tumor depending on the cellular pattern and identifying the presence metastases in the different organs collected.El osteossarcoma es considerado el tumor óseo más común en perros, afecta principalmente el esqueleto apendicular de animales adultos o seniles, con edad media de siete años. La etiología del osteossarcoma apendicular canino aún permanece desconocida. Algunos factores predisponen al surgimiento de esta neoplasia, tales como: tamaño, raza y familia. La neoplasia puede ser clasificada por las características macroscópicas y radiológicas en simple, compuesta o pleomórfica. El presente artículo es un relato de caso de osteossarcoma de tipo compuesto con metástasis en pericardio, pulmón, pleura, músculos intercostales, hígado y riñones en una perra de raza Labrador Retriver. En este, se describe la historia clínica del animal, que junto con las alteraciones observadas en la necropsia y el examen histopatológico confirmaron la causa de la muerte. Se concluye que el examen histopatológico es importante para clasificar el tumor por su patrón celular e identificar la presencia de metástasis en los diferentes órganos colectados

    Partial substitution of bean (Phaseolus vulgaris) flour for fishmeal in extruded diets for rainbow trout (Oncorhynchus mykiss): Effects on yield parameters

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    The objective of this research was to evaluate yield parameters (gained weight, weight percentage, survival, feed conversion factor (FCR), feed conversion efficiency (FCE), condition factor (K), specific growth rate (SGR) and hepatosomatic index (HSI)) of trouts fed with experimental diets elaborated with bean (Phaseolus vulgaris L.) flour instead of fishmeal with 15, 30 and 45% (BF15, BF30 and BF45, respectively) for 32 days, as well as a control diet (CD). The greatest weight gain was presented by fish fed with BF15 and BF30 (14.48 and 14.14 g, respectively) with no significant differences (p>0.05) and an approximate increase of 50% of their initial weight. FCR did not show significant differences (p>0.05) among CD, BF15 and BF30 diets with an average value of 2.05. FCE did not show significant differences (p>0.05) between diets BF15 and BF30 with an average value of 46.70%. SGR did not show significant differences (p>0.05) between BF15 and BF30 diets with an average value of 1.25. It is concluded that 30% is the maximum substitution without causing a decrease in yield and nutritional parameters in rainbow trout under the experiment conditions, although further research is suggested

    Nuevo flavonoide glicosilado de miconia coronata (bonpl.) y actividad antibacterial

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    En la búsqueda de agentes antimicrobianos, se escogió la planta Miconia coronata (melastomataceae). Se evaluó la actividad antibacterial de sus fracciones frente a Salmonella tiphymurium ATCC 13311, Salmonella gallinarum, Escherichia coli resistente a amoxicilina, Escherichia coli sensible a amoxicilina y Staphylococcus aureus ATCC 25923 por el Método de perforación de placas de agar nutritivo. De esta especie se aislaron el ácido elágico (3), un nuevo flavonoide identificado como kaemferol-7-O-4-a,ß -ramnósido (1) y una isoflavona diglicosilada (3), los cuales se caracterizaron por medio de las técnicas: espectrofotometría UV, GCMS, RMN_1H, RMN_13C, COSY. El compuesto (1) presentó importante actividad antibacterial con MIC de 256 μg/mL

    A High Statistics Measurement of the Lambdac+ Lifetime

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    A high statistics measurement of the Lambdac+ lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis technique with particular attention to the determination of the systematic uncertainty. The measured value of 204.6 +/- 3.4 (stat.) +/- 2.5 (syst.) fs from 8034 +/- 122 Lambdac -> pKpi decays represents a significant improvement over the present world average.Comment: Submitted to Physical Review Letter

    Search for CP Violation in the decays D+ -> K_S pi+ and D+ -> K_S K+

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    A high statistics sample of photo-produced charm from the FOCUS(E831) experiment at Fermilab has been used to search for direct CP violation in the decays D+->K_S pi+ and D+ -> K_S K+. We have measured the following asymmetry parameters relative to D+->K-pi+pi+: A_CP(K_S pi+) = (-1.6 +/- 1.5 +/- 0.9)%, A_CP(K_S K+) = (+6.9 +/- 6.0 +/- 1.5)% and A_CP(K_S K+) = (+7.1 +/- 6.1 +/- 1.2)% relative to D+->K_S pi+. The first errors quoted are statistical and the second are systematic. We also measure the relative branching ratios: \Gamma(D+->\bar{K0}pi+)/\Gamma(D+->K-pi+pi+) = (30.60 +/- 0.46 +/- 0.32)%, \Gamma(D+->\bar{K0}K+)/\Gamma(D+->K-pi+pi+) = (6.04 +/- 0.35 +/- 0.30)% and \Gamma(D+->\bar{K0}K+)/\Gamma(D+->\bar{K0}pi+) = (19.96 +/- 1.19 +/- 0.96)%.Comment: 4 pages, 3 figure

    A measurement of branching ratios of D+D^+ and Ds+D^+_s hadronic decays to four-body final states containing a KSK_S

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    We have studied hadronic four-body decays of D+D^+ and Ds+D^+_s mesons with a KSK_S in the final state using data recorded during the 1996-1997 fixed-target run at Fermilab high energy photoproduction experiment FOCUS. We report a new branching ratio measurement of Γ(D+KSKπ+π+)/Γ(D+KSπ+π+π)=0.0768±0.0041±0.0032\Gamma(D^+\to K_S K^-\pi^+\pi^+)/\Gamma(D^+\to K_S \pi^+\pi^+\pi^-)=0.0768\pm0.0041\pm0.0032. We make the first observation of three new decay modes with branching ratios Γ(D+KSK+π+π)/Γ(D+KSπ+π+π)=0.0562±0.0039±0.0040\Gamma(D^+\to K_S K^+\pi^+\pi^-)/\Gamma(D^+\to K_S \pi^+\pi^+\pi^-)=0.0562\pm0.0039\pm0.0040, \Gamma(D^+\to\K_S K^+ K^-\pi^+)/\Gamma(D^+\to K_S \pi^+\pi^+\pi^-)=0.0077\pm0.0015\pm0.0009, and Γ(Ds+KSK+π+π)/Γ(Ds+KSKπ+π+)=0.586±0.052±0.043\Gamma(D^+_s\to K_S K^+\pi^+\pi^-)/\Gamma(D^+_s\to K_S K^-\pi^+\pi^+)=0.586\pm0.052\pm0.043, where in each case the first error is statistical and the second error is systematic.Comment: 4 pages, 1 table, 2 figures, submitted to Physical Review Letter

    Search for CP violation in D0 and D+ decays

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    A high statistics sample of photoproduced charm particles from the FOCUS (E831) experiment at Fermilab has been used to search for CP violation in the Cabibbo suppressed decay modes D+ to K-K+pi+, D0 to K-K+ and D0 to pi-pi+. We have measured the following CP asymmetry parameters: A_CP(K-K+pi+) = +0.006 +/- 0.011 +/- 0.005, A_CP(K-K+) = -0.001 +/- 0.022 +/- 0.015 and A_CP(pi-pi+) = +0.048 +/- 0.039 +/- 0.025 where the first error is statistical and the second error is systematic. These asymmetries are consistent with zero with smaller errors than previous measurements.Comment: 12 pages, 4 figure
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