680 research outputs found

    Estimating Defensive Cyber Operator Decision Confidence

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    As technology continues to advance the domain of cyber defense, signature and heuristic detection mechanisms continue to require human operators to make judgements about the correctness of machine decisions. Human cyber defense operators rely on their experience, expertise, and understanding of network security, when conducting cyber-based investigations, in order to detect and respond to cyber alerts. Ever growing quantities of cyber alerts and network traffic, coupled with systemic manpower issues, mean no one has the time to review or change decisions made by operators. Since these cyber alert decisions ultimately do not get reviewed again, an inaccurate decision could cause grave damage to the network and host systems. The Cyber Intruder Alert Testbed (CIAT), a synthetic task environment (STE), was expanded to include investigative pattern of behavior monitoring and confidence reporting capabilities. By analyzing the behavior and confidence of participants while they conducted cyber-based investigations, this research was able to identify a mapping between investigative patterns of behavior and decision confidence. The total time spent on a decision, the time spent using different investigative tools, and total number of tool transitions, were all factors which influenced the reported confidence of participants when conducting cyber-based investigations

    Pathologies Affecting Reef Corals at the Flower Garden Banks, Northwestern Gulf of Mexico

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    The Flower Garden Banks are high-latitude reefs consisting of coral caps on the top of salt domes in the northwestern Gulf of Mexico. Limited studies to date report low incidence of coral disease on these reefs. Surveys were conducted to document the extent of coral diseases throughout the Flower Garden Banks, including types of disease present, species affected, percentage of recent colony mortality, cases of false disease, and descriptions of new pathologies. Very few of the known (or reported) Western Atlantic diseases were found, and they occurred at extremely low frequencies. Tissue-skeletal anomalies were common. Several conditions resembled known diseases, although their appearance was not wholly consistent with described pathologies and they may represent different conditions. Both ridge-mortality disease and rapid wasting disease were confirmed to be the result of fish biting activities. Several novel pathologic conditions that do not fit the description or known etiology of any currently described coral disease were discovered at relatively high prevalence rates. Because of an absence of standardized coral disease nomenclature and the unknown etiology of these novel syndromes, they are tentatively named pale ring, pale patch, and mottling syndromes on the basis of field characteristics

    Improving probe set selection for microbial community analysis by leveraging taxonomic information of training sequences

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    <p>Abstract</p> <p>Background</p> <p>Population levels of microbial phylotypes can be examined using a hybridization-based method that utilizes a small set of computationally-designed DNA probes targeted to a gene common to all. Our previous algorithm attempts to select a set of probes such that each training sequence manifests a unique theoretical hybridization pattern (a binary fingerprint) to a probe set. It does so without taking into account similarity between training gene sequences or their putative taxonomic classifications, however. We present an improved algorithm for probe set selection that utilizes the available taxonomic information of training gene sequences and attempts to choose probes such that the resultant binary fingerprints cluster into real taxonomic groups.</p> <p>Results</p> <p>Gene sequences manifesting identical fingerprints with probes chosen by the new algorithm are more likely to be from the same taxonomic group than probes chosen by the previous algorithm. In cases where they are from different taxonomic groups, underlying DNA sequences of identical fingerprints are more similar to each other in probe sets made with the new versus the previous algorithm. Complete removal of large taxonomic groups from training data does not greatly decrease the ability of probe sets to distinguish those groups.</p> <p>Conclusions</p> <p>Probe sets made from the new algorithm create fingerprints that more reliably cluster into biologically meaningful groups. The method can readily distinguish microbial phylotypes that were excluded from the training sequences, suggesting novel microbes can also be detected.</p

    Cellular immune response to intrastriatally implanted allogeneic bone marrow stromal cells in a rat model of Parkinson's disease

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    <p>Abstract</p> <p>Background</p> <p>Marrow stromal cells (MSC), the non-hematopoietic precursor cells in bone marrow, are being investigated for therapeutic potential in CNS disorders. Although <it>in vitro </it>studies have suggested that MSC may be immunologically inert, their immunogenicity following transplantation into allogeneic recipients is unclear. The primary objective of this study was to investigate the cellular immune response to MSC injected into the striatum of allogeneic recipients (6-hydroxydopamine [6-OHDA]-hemilesioned rats, an animal model of Parkinson's disease [PD]), and the secondary objective was to determine the ability of these cells to prevent nigrostriatal dopamine depletion and associated motor deficits in these animals.</p> <p>Methods</p> <p>5-Bromo-2-deoxyuridine (BrdU) – labeled MSC from two allogeneic sources (Wistar and ACI rats) were implanted into the striatum of adult Wistar rats at the same time as 6-OHDA was administered into the substantia nigra. Behavioral tests were administered one to two weeks before and 16–20 days after 6-OHDA lesioning and MSC transplantation. Immunocytochemical staining for T helper and T cytotoxic lymphocytes, microglia/macrophages, and major histocompatibility class I and II antigens was performed on post-transplantation days 22–24. MSC were detected with an anti-BrdU antibody.</p> <p>Results</p> <p>Tissue injury due to the transplantation procedure produced a localized cellular immune response. Unexpectedly, both sources of allogeneic MSC generated robust cellular immune responses in the host striatum; the extent of this response was similar in the two allograft systems. Despite these immune responses, BrdU<sup>+ </sup>cells (presumptive MSC) remained in the striatum of all animals that received MSC. The numbers of remaining MSC tended to be increased (<it>p </it>= 0.055) in rats receiving Wistar MSC versus those receiving ACI MSC. MSC administration did not prevent behavioral deficits or dopamine depletion in the 6-OHDA-lesioned animals.</p> <p>Conclusion</p> <p>MSC, when implanted into the striatum of allogeneic animals, provoke a marked immune response which is not sufficient to clear these cells by 22–24 days post-transplantation. In the experimental paradigm in this study, MSC did not prevent nigrostriatal dopamine depletion and its associated behavioral deficits. Additional studies are indicated to clarify the effects of this immune response on MSC survival and function before initiating trials with these cells in patients with PD or other neurodegenerative disorders.</p

    Bianisotropic Effective Parameters of Optical Metamagnetics and Negative-Index Materials

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    Approaches to the adequate homogenization of optical metamaterials are becoming more and more complex, primarily due to an increased understanding of the role of asymmetric electrical and magnetic responses, in addition to the nonlocal effects of the surrounding medium, even in the simplest case of plane-wave illumination. The current trend in developing such advanced homogenization descriptions often relies on utilizing bianisotropic models as a base on top of which novel optical characterization techniques can be built. In this paper, we first briefly review general principles for developing a bianisotropic homogenization approach. Second, we present several examples validating and illustrating our approach using single-period passive and active optical metamaterials. We also show that the substrate may have a significant effect on the bianisotropic characteristics of otherwise symmetric passive and active metamaterials

    Harm avoidance is related to mismatch negativity (MMN) amplitude in healthy subjects

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    peer reviewedEvent-related potential (ERP) studies evidenced that some personality dimensions induced different controlled cognitive attitudes towards the processing of information. However, few data are available on the possible relationships between personality and automatic attention or early sensory processing. In the present study the relationships between the mismatch negativity (MMN) and personality described by the Cloninger model of personality were investigated. Subjects were 32 healthy volunteers. The MMN was recorded with frequent stimuli tones of 1470 Hz, 70 dB and 40 ms duration, and target (20%) tones of 1470 Hz, 70 dB, 80 ms duration. The subjects completed a French version of the 226-item self-questionnaire TCI within the day following psychophysiological recording. The results showed that the HA dimension was negatively correlated with the MMN amplitude. The association was more present among women than men. No significant relationship existed between the other dimensions of personality and either the MMN amplitude or latency. These findings suggest that the MMN is related to the behavioral inhibition system (BIS), a fact which is consistent with clinical studies conducted on schizophrenia and anxiety disorders. In conclusion, this study suggests that personality dimensions induce different automatic attitudes towards the processing of information. (C) 2002 Published by Elsevier Science Ltd

    How U.S. Ocean Policy and Market Power Can Reform the Coral Reef Wildlife Trade

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    As the world’s largest importer of marine ornamental species for the aquaria, curio, home décor, and jewelry industries, the United States has an opportunity to leverage its considerable market power to promote more sustainable trade and reduce the effects of ornamental trade stress on coral reefs worldwide. Evidence indicates that collection of some coral reef animals for these trades has caused virtual elimination of local populations, major changes in age structure, and promotion of collection practices that destroy reef habitats. Management and enforcement of collection activities in major source countries such as Indonesia and the Philippines remain weak. Strengthening US trade laws and enforcement capabilities combined with increasing consumer and industry demand for responsible conservation can create strong incentives for improving management in source countries. This is particularly important in light of the March 2010 failure of the parties to the Convention on International Trade in Endangered Species (CITES) to take action on key groups of corals

    Музейна справа сучасної Франції на прикладі музею Бранлі

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    The article sums up the results of the first year of operation du quai Braniy. It also sheds light on multicultural image of modern France
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