642 research outputs found
Bulk dynamics for interfacial growth models
We study the influence of the bulk dynamics of a growing cluster of particles
on the properties of its interface. First, we define a {\it general bulk growth
model} by means of a continuum Master equation for the evolution of the bulk
density field. This general model just considers arbitrary addition of
particles (though it can be easily generalized to consider substraction) with
no other physical restriction. The corresponding Langevin equation for this
bulk density field is derived where the influence of the bulk dynamics is
explicitly shown. Finally, when it is assumed a well-defined interface for the
growing cluster, the Langevin equation for the height field of this interface
for some particular bulk dynamics is written. In particular, we obtain the
celebrated Kardar-Parisi-Zhang (KPZ) equation. A Monte Carlo simulation
illustrates the theoretical results.Comment: 6 pages, 2 figure
Collisional rates for the inelastic Maxwell model: application to the divergence of anisotropic high-order velocity moments in the homogeneous cooling state
The collisional rates associated with the isotropic velocity moments
and
are exactly derived in the case of the
inelastic Maxwell model as functions of the exponent , the coefficient of
restitution , and the dimensionality . The results are applied to
the evolution of the moments in the homogeneous free cooling state. It is found
that, at a given value of , not only the isotropic moments of a degree
higher than a certain value diverge but also the anisotropic moments do. This
implies that, while the scaled distribution function has been proven in the
literature to converge to the isotropic self-similar solution in well-defined
mathematical terms, nonzero initial anisotropic moments do not decay with time.
On the other hand, our results show that the ratio between an anisotropic
moment and the isotropic moment of the same degree tends to zero.Comment: 7 pages, 2 figures; v2: clarification of some mathematical statements
and addition of 7 new references; v3: Published in "Special Issue: Isaac
Goldhirsch - A Pioneer of Granular Matter Theory
Viability of competing field theories for the driven lattice gas
It has recently been suggested that the driven lattice gas should be
described by a novel field theory in the limit of infinite drive. We review the
original and the new field theory, invoking several well-documented key
features of the microscopics. Since the new field theory fails to reproduce
these characteristics, we argue that it cannot serve as a viable description of
the driven lattice gas. Recent results, for the critical exponents associated
with this theory, are re-analyzed and shown to be incorrect.Comment: 4 pages, revtex, no figure
EVALUATION OF BONE MINERAL DENSITY USING RADIOGRAPHIC OPTICAL DENSITOMETRY OF PRE AND POSTPUBERTAL BITCHES SUBMITTED TO OVARIOHYSTERECTOMY
The reduction of gonadal steroid hormone secretion is identified as one ofthe factors responsible for the decrease in bone mass and, consequently, a decrease in bone mineral density. The study aimed to evaluate the bone mineral density by using radiographic optical densitometry of the distal epiphyseal region of the radius and ulna in prepubertal and post pubertal bitches submitted to ovariohysterectomy (OVH). Thirtyfour female dogs were divided into two groups of 16 animals, according with age of neutering: G1 - prepubertal bitches submitted to OVH; G2 - postpubertal bitches submitted to OVH. The animals were submitted to the evaluation of bone mineral density at 24 h before the surgical procedure, 24 and 48 weeks after the surgical procedure. No significant differences in bone mineral density were identified in all groups. Ovariohysterectomy in pre and postpubertal bitches did not induce significant variations in bone mineral density of the distal epiphyseal region of the radius and ulna by using radiographic optical densitometry, during 48 weeks of evaluation
Echovirus 13 Aseptic Meningitis, Brazil
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Previous issue date: 2006Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil.Secretaria Municipal de Saúde do Rio Grande do Sul. Rio Grande, RS, Brasil.Instituto de Pesquisas Biológicas. Rio Grande, RS, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil
Malware Distributed Collection And Pre-classification System Using Honeypot Technology
Malware has become a major threat in the last years due to the ease of spread through the Internet. Malware detection has become difficult with the use of compression, polymorphic methods and techniques to detect and disable security software. Those and other obfuscation techniques pose a problem for detection and classification schemes that analyze malware behavior. In this paper we propose a distributed architecture to improve malware collection using different honeypot technologies to increase the variety of malware collected. We also present a daemon tool developed to grab malware distributed through spam and a pre-classification technique that uses antivirus technology to separate malware in generic classes. © 2009 SPIE.7344Grossman, J., Niedzialkowski, T.C., Hacking Intranet Websites from the Outside - Javascript malware just got a lot more dangerous (2006) Black Hat, , http://www.blackhat.com/presentations/bhusa-06/BH-US-06-Grossman.pdf, USA, Las Vegas, Available atWhitehouse, O., An Analysis of Address Space Layout Randomization on Windows Vista (2007) Symantec Advanced Threat Research, , http://www.symantec.com/avcenter/reference/Address-Space-Layout-Randomization.pdf, White paper available atWhitehouse, O., Analysis of GS Protections in Microsoft Windows Vista (2007) Symantec Advanced Threat Research, , http://www.symantec.com/avcenter/reference/GS-Protections-in-Vista.pdf, White paper available atMcDermott, J., Fox, C., Using abuse cases models for security requirement analysis (1999) Proceedings of the 15th Annual Computer Security Applications Conference, p. 55. , IEEE Computer Society, ISBN:0-7695-0346-2Collection, , http://Nepenthes.carnivore.it, Available at:, Accessed on January 2009Baecher, P., The Nepenthes Platform: An Efficient Approach to Collect Malware (2006) Recent Advances in Intrusion Detection, pp. 165-184. , Springer Berlin, HeidelbergHoneytrap, , http://honeytrap.mwcollect.org, Available at:, Accessed on January 2009Zhuge, J., Holz, T., Han, X., Song, C., Zou, W., Collecting Autonomous Spreading Malware Using Highinteraction Honeypots (2007) Proceedings of 9th International Conference on Information and Communications Security (ICICS'07), , Zhengzhou, China, DecemberProvos, N., Holz, T., (2007) Virtual Honeypots: From Botnet Tracking to Intrusion Detection, , Addison Wesley, ISBN: 0-321-33632-1Seifert, C., Welch, I., Komisarczuk, P., HoneyC - The Low-Interaction Client Honeypot (2007) Proceedings of the 2007 NZCSRCS, , Waikato University, Hamilton, New Zealand, AprilNazario, J., Phoneyc, , http://svn.carnivore.it/browser/phoneyc, Accessed on January 2009Seifert, C., Steenson, R., Holz, T., Yuan, B., Davis, M.A., Know Your Enemy: Malicious Web Servers, , http://www.honeynet.org/papers/mws, Available at:, Accessed on January 2009Spitzner, L., (2002) Honeypots: Tracking Hackers, , Addison Wesley, ISBN: 0-321-10895-1http://www.honeypots-alliance.org.br, Brazilian Honeypots Alliance, Distributed Honeypots Project. Available at:, Accessed on January 200
Choosing components in the additive main effect and multiplicative interaction (AMMI) models
Green manure in coffee systems in the region of Zona da Mata, Minas Gerais: characteristics and kinetics of carbon and nitrogen mineralization.
The use of green manure may contribute to reduce soil erosion and increase the soil organic matter content and N availability in coffee plantations in the Zona da Mata, State of Minas Gerais, in Southeastern Brazil. The potential of four legumes (A. pintoi, C. mucunoides, S. aterrimum and S. guianensis)to produce above-ground
biomass, accumulate nutrients and mineralize N was studied in two coffee plantations of subsistence farmers under different climate conditions. The biomass production of C. mucunoides was influenced by the shade of the coffee plantation.C. mucunoides tended to mineralize more N than the other legumes due to the low polyphenol content and polyphenol/N ratio. In the first year, the crop establishment of A. pintoi in the area took longer than of the other legumes, resulting in lower biomass production and N2 fixation. In the long term, cellulose was the main
factor controlling N mineralization. The biochemical characteristics, nutrient accumulation and biomass production of the legumes were greatly influenced by
the altitude and position of the area relative to the sun
Indicadores De Desempenho Motor Como Preditores De Fragilidade Em Idosos Cadastrados Em Uma Unidade De Saúde Da Família
This study aimed to identify the motor performance tests more strongly associated with frailty and respective cut-off points and verify the best motor performance indicator as screening tool to discriminate frailty in elderly registered in Family Health Unit Participated in the study 139 elderly aged ≥60 years 105 women and 34 men The frailty was identified by the criteria of Fried et al (2001) The motor performance tests realized were: Handgrip strength (HS) sit-to-stand test walk test (WT) and pick up a pen test Logistic regression analysis was used to associate the motor performance tests and frailty The cutoff points were evaluated by parameters provided by Receiver Operating Characteristic curve (ROC) with significance level of 5% Data were analyzed using SPSS 210 and MedCalc The mean age was 7232 ± 84 The walk test was positively associated with frailty (OR 130; p <001) and handgrip strength in elderly women was inversely associated with frailty on feminine sex (OR 074; p <0001) The WT presented a cutoff 5s (sensitivity 889 and specificity 745%) and the handgrip in the women obtained a cutoff point 146 kgf (sensitivity 833 and specificity 790%) It was concluded that the walk test was the best screening indicator to discriminate the frailty in elderly both sexes registered in a Family Health Unit. © Edições Desafio Singular.122889
Qualidade fisiológica de sementes de milho sob diferentes condições de armazenamento
This study aims to examine the quality of corn seeds stored under different conditions from May to October, 2008. The experiment was conducted at the Research Laboratory of Seed Analysis of Federal University of Tocantins, Gurupi Campus, with seeds of commercial cultivars of corn obtained in the F2 generation, stored under the environmental conditions of the state of Tocantins, and in cold chamber (20 °C, and relative humidity of 20%). In order to obtain the salt stress, solutions of potassium chloride (KCl) were used in the following concentrations (mol m-3): zero (T1), 30 (T2), 90 (T3), 170 (T4) and 260 (T5). In order to evaluate the quality of seeds, the following tests were made: germination, germination speed index, seed health and seedling length. The experimental design was a randomized complete block with three replications in a factorial 2x5 (storage conditions x concentration of KCl). Subsequent analysis of ANOVA and application of Tukey's test at 5% were carried out. The average percentage of seed germination was 3.86% and 94% for the storage environmental conditions and cold chamber, respectively. At the highest concentration of KCl, seedlings were 18.33 mm seedling-1 shoot length, and at the lowest concentration, the control, 74 mm seedling-1. The results showed that environmental conditions from May to October in Gurupi, state of Tocantins, are not suitable for storage of seed corn without refrigeration.O objetivo deste trabalho foi avaliar a qualidade de sementes de milho armazenadas em diferentes condições, durante os meses de maio a outubro de 2008. O experimento foi conduzido no Laboratório de Pesquisa em Análise de Sementes do Campus Universitário de Gurupi - TO, da Universidade Federal do Tocantins, utilizando-se sementes de cultivares comerciais de milho obtidas na geração F2, armazenadas em condições ambientais do estado do Tocantins, e em câmara fria (20 °C, e umidade relativa de 20%). Utilizou-se soluções de cloreto de potássio (KCl) para a obtenção do estresse salino, nas seguintes concentrações (mol m-3): zero (T1); 30 (T2); 90 (T3); 170 (T4) e 260 (T5). Para a avaliação da qualidade das sementes testou-se: a germinação, o índice de velocidade de germinação, sanidade das sementes e o comprimento de plântula. Adotou-se o delineamento experimental inteiramente casualizado, com três repetições, num esquema fatorial 2x5 (condições de armazenamento x concentração de KCl), posteriormente foi realizada análise de variância e aplicado o teste de Tukey a 5%. As porcentagens médias de germinação, das sementes, foram de 3,86% e 94% para as condições de armazenamento ambiente e câmara fria, respectivamente. Na maior concentração de KCl as plântulas apresentaram 18,33 mm plântula-1 de comprimento de parte área, sendo que na menor concentração, a testemunha, 74 mm plântula-1. As condições ambientais de Gurupi-TO, Estado do Tocantins, nos meses de maio à outubro são pouco apropriadas ao armazenamento de sementes de milho sem refrigeração
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