A Study of the Relationship Between Antivirus Regressions and Label Changes

AntiVirus (AV) products use multiple components to detect malware. A component which is found in virtually all AVs is the signature-based detection engine: this component assigns a particular signature label to a malware that the AV detects. In previous analysis [1-3], we observed cases of regressions in several different AVs: i.e. cases where on a particular date a given AV detects a given malware but on a later date the same AV fails to detect the same malware. We studied this aspect further by analyzing the only externally observable behaviors from these AVs, namely whether AV engines detect a malware and what labels they assign to the detected malware. In this paper we present the results of the analysis about the relationship between the changing of the labels with which AV vendors recognize malware and the AV regressions

Comparing Detection Capabilities of AntiVirus Products: An Empirical Study with Different Versions of Products from the Same Vendors

In this paper we report results of an empirical analysis of the detection capabilities of 9 AntiVirus (AV) products when they were subjected to 3605 malware samples collected on an experimental network over a period of 31 days in NovemberDecember 2013. We compared the detection capabilities of the version of the AV products that the vendors make available for free in VirusTotal versus the full capability products that they make available via their own website. The analysis has been done using externally observable properties of the AV products: namely whether they detect a given malware. The paper reports extensive analysis of the results. A surprising finding of our study was that only one of the vendors had a full capability version which detected all the malware that their VirusTotal version could detect

Uso de marcação não radiativa para identificação de grandes rearranjos gênicos na deficiência da 21-hidroxilase

PURPOSE: To establish the Southern blotting technique using hybridization with a nonradioactive probe to detect large rearrangements of CYP21A2 in a Brazilian cohort with congenital adrenal hyperplasia due to 21-hydroxylase deficiency (CAH-21OH). METHOD: We studied 42 patients, 2 of them related, comprising 80 non-related alleles. DNA samples were obtained from peripheral blood, digested by restriction enzyme Taq I, submitted to Southern blotting and hybridized with biotin-labeled probes. RESULTS: This method was shown to be reliable with results similar to the radioactive-labeling method. We found CYP21A2 deletion (2.5%), large gene conversion (8.8%), CYP21AP deletion (3.8%), and CYP21A1P duplication (6.3%). These frequencies were similar to those found in our previous study in which a large number of cases were studied. Good hybridization patterns were achieved with a smaller amount of DNA (5 mug), and fragment signs were observed after 5 minutes to 1 hour of exposure. CONCLUSIONS: We established a non-radioactive (biotin) Southern blot/hybridization methodology for CYP21A2 large rearrangements with good results. Despite being more arduous, this technique is faster, requires a smaller amount of DNA, and most importantly, avoids problems with the use of radioactivity.OBJETIVO: Padronizar a técnica de Southern blotting usando hibridização com material não radioativo para detectar grandes rearranjos no gene CYP21A2 em uma amostra da população brasileira com hiperplasia adrenal congênita. MÉTODO: Foram estudados 42 pacientes, 2 dos quais aparentados, totalizando 80 alelos não relacionados. As amostras de DNA foram obtidas de sangue periférico, digeridas com enzima de restrição Taq I, realizado Southern blotting e hibridizadas com sonda marcada com biotina. RESULTADOS: O método se mostrou eficaz, com resultados similares aos encontrados ao utilizar a metodologia com material radioativo. Foram encontradas 2,5% de deleção do CYP21A2, 8,8% de grandes conversões, 3,8% de deleção do CYP21A1P e 6,3% de duplicação do CYP21A1P. Estas freqüências foram similares às encontradas em nosso estudo prévio, onde um número significante de casos foi estudado. Um bom padrão de hibridização foi alcançado utilizando menor quantidade de DNA (5mg) e a emissão de sinais foi observada entre 5 minutos e 1 hora de exposição. CONCLUSÕES: Padronizamos uma técnica de Southern blotting/ hibridização com material não radioativo (biotina) para a pesquisa de grandes rearranjos no gene CYP21A2 com bons resultados. Apesar de ser mais trabalhoso, este método é mais rápido, utiliza menores quantidades de DNA e, principalmente, evita problemas com o uso de radioatividade

Strong coupling theory for driven tunneling and vibrational relaxation

We investigate on a unified basis tunneling and vibrational relaxation in driven dissipative multistable systems described by their N lowest lying unperturbed levels. By use of the discrete variable representation we derive a set of coupled non-Markovian master equations. We present analytical treatments that describe the dynamics in the regime of strong system-bath coupling. Our findings are corroborated by ``ab-initio'' real-time path integral calculations.Comment: 4 LaTeX pages including 3 figure

Arabidopsis seedlings display a remarkable resilience under severe mineral starvation using their metabolic plasticity to remain self-sufficient for weeks

During the life cycle of plants, seedlings are considered vulnerable because they are at the interface between the highly stress tolerant seed embryos and the established plant, and must develop rapidly, often in a challenging environment, with limited access to nutrients and light. Using a simple experimental system, whereby the seedling stage of Arabidopsis is considerably prolonged by nutrient starvation, we analysed the physiology and metabolism of seedlings maintained in such conditions up to 4 weeks. Although development was arrested at the cotyledon stage, there was no sign of senescence and seedlings remained viable for weeks, yielding normal plants after transplantation. Photosynthetic activity compensated for respiratory carbon losses, and energy dissipation by photorespiration and alternative oxidase appeared important. Photosynthates were essentially stored as organic acids, while the pool of free amino acids remained stable. Seedlings lost the capacity to store lipids in cytosolic lipid droplets, but developed large plastoglobuli. Arabidopsis seedlings arrested in their development because of mineral starvation displayed therefore a remarkable resilience, using their metabolic and physiological plasticity to maintain a steady state for weeks, allowing resumption of development when favourable conditions ensue

Cirurgia de revascularização do miocárdio: complicações pleuro-pulmonares agudas caracterizadas por tomografia computadorizada de tórax

INTRODUCTION: Pleuropulmonary changes are common following coronary artery bypass grafting surgery performed with a saphenous vein graft, with or without an internal mammary artery. The presence of atelectasis or pleural effusions reflects the thoracic trauma. PURPOSE: To define the postoperative incidence of changes in the lung and in the pleural space and to evaluate the influence of the trauma. METHODS: Thirty patients underwent elective coronary artery bypass grafting surgery (8 saphenous vein grafts and 22 saphenous vein grafts and internal mammary artery grafts with pleurotomy). Chest tubes in the left pleural space were used in all internal mammary artery patients. On the second (day 2) and seventh (day 7) postoperative day, patients underwent a computed tomography, and pleural effusions were rated as follows: grade 0 = no fluid to grade 4 = fluid in more than 75% of the hemithorax. Atelectasis was rated as follows: laminar = 1, segmental = 3, and lobar = 10 points. RESULTS: All patients had pleural effusion or atelectasis. Between day 2 and day 7, the number of patients with effusions or atelectasis on the right side decreased (P < 0.05). The incidence of effusions on day 2 in the saphenous vein graft group (87.5%) was higher (P < 0.05) than in the internal mammary artery group (52.3%). The incidence of atelectasis in the lower right lobe decreased (P < 0.05) from 86.7% (day 2) to 26.7% (day 7). The degree of atelectasis in both sides did not differ on day 2 (P = 0.42) but did on day 7 (P < 0.0001). There was a decrease in the atelectasis from day 2 to day 7 on the right side (P < 0.001), but not on the left (P = 0.21). On day 2 there was a relationship between atelectasis and effusion on the right (P = 0.04), but not on the left (P = 0.113). CONCLUSION: The present series demonstrates that there is a high incidence of both minimal pleural effusion and atelectasis after coronary artery bypass grafting surgery, which drops on the right side from day 2 to day 7 post surgery. Factors that contribute to the persistence of changes on the left side include the thoracic trauma and the presence of chest tubes and pericardial effusion.INTRODUÇÃO: O comprometimento pleuro-pulmonar é freqüente após cirurgia de revascularização do miocárdio independente do uso de veia safena ou de artéria mamária interna. A presença de atelectasias e derrame pleural tem sido atribuída ao trauma torácico. OBJETIVOS: Definir a incidência do comprometimento pleuro-pulmonar observado através de tomografia computadorizada, analisando a influência do trauma no desenvolvimento destas complicações. MÉTODOS: Trinta pacientes foram submetidos a cirurgia eletiva de revascularização do miocárdio (8 safena e 22 também mamária com pleurotomia). Foi drenada a cavidade pleural esquerda de todos os pacientes do grupo mamária. Realizada Tomografia Computadorizada do tórax no 2º e 7º dias pós-op, avaliando-se o derrame pleural (0: sem líquido e 4: derrame em mais de 75% do hemitórax) e atelectasias (laminar: 1, segmentar: 3 e lobar: 10 pontos). RESULTADOS: Todos os pacientes apresentaram derrame pleural ou atelectasia. Entre o 2º e o 7º dia, o número de pacientes com derrame ou com atelectasia, no lado direito, diminuiu (p < 0.05). A prevalência de derrames, no 2º dia, no grupo safena, (87.5%) foi maior (p < 0.05) do que no grupo mamária (52.3%). A prevalência de atelectasias no lobo inferior direito diminuiu (p < 0.05) de 86.7% (2º dia) para 26.7% (7º dia). O grau de atelectasias, em ambos os lados, não diferiu no dia 2 (p = 0,42) mas sim no dia 7 (p < 0.0001). Houve diminuição das atelectasias do dia 2 para o 7, à direita (p < 0.001), mas não à esquerda (p = 0.21). Houve correlação (dia 2) entre as atelectasias e os derrames à direita (p = 0.04), mas não à esquerda (p = 0.113). CONCLUSÃO: Este estudo evidencia alta prevalência de derrame pleural e atelectasias após cirurgia de revascularização do miocárdio, que se reduz à direita no 7º dia de pós-operatório. Os fatores envolvidos na persis-tência das alterações à esquerda incluem o maior trauma torácico, ressaltando-se a drenagem e a presença de derrame pericárdico

Input variable selection in time-critical knowledge integration applications: A review, analysis, and recommendation paper

This is the post-print version of the final paper published in Advanced Engineering Informatics. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2013 Elsevier B.V.The purpose of this research is twofold: first, to undertake a thorough appraisal of existing Input Variable Selection (IVS) methods within the context of time-critical and computation resource-limited dimensionality reduction problems; second, to demonstrate improvements to, and the application of, a recently proposed time-critical sensitivity analysis method called EventTracker to an environment science industrial use-case, i.e., sub-surface drilling. Producing time-critical accurate knowledge about the state of a system (effect) under computational and data acquisition (cause) constraints is a major challenge, especially if the knowledge required is critical to the system operation where the safety of operators or integrity of costly equipment is at stake. Understanding and interpreting, a chain of interrelated events, predicted or unpredicted, that may or may not result in a specific state of the system, is the core challenge of this research. The main objective is then to identify which set of input data signals has a significant impact on the set of system state information (i.e. output). Through a cause-effect analysis technique, the proposed technique supports the filtering of unsolicited data that can otherwise clog up the communication and computational capabilities of a standard supervisory control and data acquisition system. The paper analyzes the performance of input variable selection techniques from a series of perspectives. It then expands the categorization and assessment of sensitivity analysis methods in a structured framework that takes into account the relationship between inputs and outputs, the nature of their time series, and the computational effort required. The outcome of this analysis is that established methods have a limited suitability for use by time-critical variable selection applications. By way of a geological drilling monitoring scenario, the suitability of the proposed EventTracker Sensitivity Analysis method for use in high volume and time critical input variable selection problems is demonstrated.E

Profile of Service Use and Barriers to Access to Care among Brazilian Children and Adolescents with Autism Spectrum Disorders

Delayed diagnosis and a lack of adequate care for people with autism spectrum disorder (ASD) are related to worse outcomes and quality of life. This study aimed to identify the profile of service use, barriers to access care, and factors related to those barriers in Brazilian families with children with ASD. A total of 927 families with children with ASD (3-17 years) from five Brazilian regions completed an online version of the Caregivers Needs Survey. Results showed that the most used services were behavioral interventions and pharmacotherapy, while the most used professionals were neurologists, nutritionists, speech therapists, psychiatrists, psychologists, and pediatricians. The main barriers included waiting lists, costs, and the absence of services or treatment. Service use varied according to age, the region of residence, type of health care system used, and the parents/caregivers\u27 education. Access to behavioral interventions was more frequent among users of the private system/health insurance and families whose caregivers had higher education. The absence of specialized services/treatments was less frequent among residents of state capitals and families whose caregivers had higher levels of education. This study highlights how families with children/adolescents with ASD in Brazil face significant barriers to access care related to sociodemographic factors

Phase diffusion as a model for coherent suppression of tunneling in the presence of noise

We study the stabilization of coherent suppression of tunneling in a driven double-well system subject to random periodic $\delta-$function ``kicks''. We model dissipation due to this stochastic process as a phase diffusion process for an effective two-level system and derive a corresponding set of Bloch equations with phase damping terms that agree with the periodically kicked system at discrete times. We demonstrate that the ability of noise to localize the system on either side of the double-well potenital arises from overdamping of the phase of oscillation and not from any cooperative effect between the noise and the driving field. The model is investigated with a square wave drive, which has qualitatively similar features to the widely studied cosinusoidal drive, but has the additional advantage of allowing one to derive exact analytic expressions.Comment: 17 pages, 4 figures, submitted to Phys. Rev.

Electron energy loss and induced photon emission in photonic crystals

The interaction of a fast electron with a photonic crystal is investigated by solving the Maxwell equations exactly for the external field provided by the electron in the presence of the crystal. The energy loss is obtained from the retarding force exerted on the electron by the induced electric field. The features of the energy loss spectra are shown to be related to the photonic band structure of the crystal. Two different regimes are discussed: for small lattice constants $a$ relative to the wavelength of the associated electron excitations $\lambda$, an effective medium theory can be used to describe the material; however, for $a\sim\lambda$ the photonic band structure plays an important role. Special attention is paid to the frequency gap regions in the latter case.Comment: 12 pages, 7 figure