1,686 research outputs found

    NoSEBrEaK - Attacking Honeynets

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    It is usually assumed that Honeynets are hard to detect and that attempts to detect or disable them can be unconditionally monitored. We scrutinize this assumption and demonstrate a method how a host in a honeynet can be completely controlled by an attacker without any substantial logging taking place

    M+D: conceptual guidelines for compiling a materials library

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    This article proposes to present a study conducted by the Raw Materials research group, the results of which comprise the conceptual guidelines for compiling an M+D material library. The study includes the topic, materials and design taking the impact of the changes that came into being in the post industrial era on project methodologies and the search for information regarding materials. Taking into account the importance and complexity that these relationships have taken on currently, we have studied the issue of materials based on Manzini (1983) and Ashby and Johnson (2002). Afterward different databases and materials libraries located in the Brazil, the United States, France and Italy geared toward design professionals and students were analyzed to understand what information and means of access to them were available. The project methodologies were approached based on Löbach (1991), Bürdeck (1994), Schulmann (1994), Baxter (1998), Dantas (1998 and 2005) and Papanek (1995 and 2000). This study sought to identify the key elements of the role of materials in the project process today, to serve as a parameter for the analysis of the models studied. A comparative analysis of the models investigated enabled identification of positive and negative aspects to adapt to the needs previously mentioned and identify conceptual guidelines for compiling a collection of materials for use in design projects. Keywords: Design, Materials, Project Methodology, Library</p

    Structured recursive separator decompositions for planar graphs in linear time (Extended Abstract)

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    Given a triangulated planar graph G on n vertices and an integer r &lt; n, an r-division of G with few holes is a decomposition of G into O(n/r) regions of size at most r such that each region contains at most a constant number of faces that are not faces of G (also called holes), and such that, for each region, the total number of vertices on these faces is O( √ r). We provide an algorithm for computing r-divisions with few holes in linear time. In fact, our algorithm computes a structure, called decomposition tree, which represents a recursive decomposition of G that includes r-divisions for essentially all values of r. In particular, given an exponentially increasing sequence r = (r1, r2, ...), our algorithm can produce a recursive r-division with few holes in linear time. r-divisions with few holes have been used in efficient algorithms to compute shortest paths, minimum cuts, and maximum flows. Our linear-time algorithm improves upon the decomposition algorithm used in the state-of-the-art algorithm for minimum st-cut (Italiano, Nussbaum, Sankowski, and Wulff-Nilsen, STOC 2011), removing one of the bottlenecks in the overall running time of their algorithm (analogously for minimum cut in planar and bounded-genus graphs)

    Absolute emission rates of Spontaneous Parametric Down Conversion into single transverse Gaussian modes

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    We provide an estimate on the absolute values of the emission rate of photon pairs produced by spontaneous parametric down conversion in a bulk crystal when all interacting fields are in single transverse Gaussian modes. Both collinear and non-collinear configurations are covered, and we arrive at a fully analytical expression for the collinear case. Our results agree reasonably well with values found in typical experiments, which allows this model to be used for understanding the dependency on the relevant experimental parameters.Comment: RevTeX, 7 pages, 4 figures; this version has a short section discussing ratios between pump and target waist

    Frequency Measurement of an Ar+ Laser Stabilized on Narrow Lines of Molecular Iodine at 501.7 nm

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    A spectrometer for ultra high-resolution spectroscopy of molecular iodine at wave length 501.7 nm, near the dissociation limit is described. Line shapes about 30 kHz wide (HWHM) were obtained using saturation spectroscopy in a pumped cell. The frequency of an Ar+ laser was locked to a hyperfine component of the R(26)62-0 transition and the first absolute frequency measurement of this line is reported

    A Comparative Transcriptome Analysis of Human and Porcine Choroid Plexus Cells in Response to Streptococcus suis Serotype 2 Infection Points to a Role of Hypoxia

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    Streptococcus suis (S. suis) is an important opportunistic pathogen, which can cause septicemia and meningitis in pigs and humans. Previous in vivo observations in S. suisinfected pigs revealed lesions at the choroid plexus (CP). In vitro experiments with primary porcine CP epithelial cells (PCPEC) and human CP epithelial papilloma (HIBCPP) cells demonstrated that S. suis can invade and traverse the CP epithelium, and that the CP contributes to the inflammatory response via cytokine expression. Here, next generation sequencing (RNA-seq) was used to compare global transcriptome profiles of PCPEC and HIBCPP cells challenged with S. suis serotype (ST) 2 infected in vitro, and of pigs infected in vivo. Identified differentially expressed genes (DEGs) were, amongst others, involved in inflammatory responses and hypoxia. The RNA-seq data were validated via quantitative PCR of selected DEGs. Employing Gene Set Enrichment Analysis (GSEA), 18, 28, and 21 enriched hallmark gene sets (GSs) were identified for infected HIBCPP cells, PCPEC, and in the CP of pigs suffering from S. suis ST2 meningitis, respectively, of which eight GSs overlapped between the three different sample sets. The majority of these GSs are involved in cellular signaling and pathways, immune response, and development, including inflammatory response and hypoxia. In contrast, suppressed GSs observed during in vitro and in vivo S. suis ST2 infections included those, which were involved in cellular proliferation and metabolic processes. This study suggests that similar cellular processes occur in infected human and porcine CP epithelial cells, especially in terms of inflammatory response

    Peptide Signatures for Prognostic Markers of Pancreatic Cancer by MALDI Mass Spectrometry Imaging

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    Simple Summary: Pancreatic cancer remains one of the most lethal tumor entities worldwide given its overall 5-year survival after diagnosis of 9%. Thus, further understanding of molecular changes to improve individual prognostic assessment as well as diagnostic and therapeutic advancement is crucial. The aim of this study was to investigate the feasibility of Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) to identify specific peptide signatures linked to established prognostic parameters of pancreatic cancer. In a patient cohort of 18 patients with exocrine pancreatic cancer after tumor resection, MALDI imaging analysis additional to histopathological assessment was performed. Applying this method to tissue sections of the tumors, we were able to identify discriminative peptide signatures corresponding to nine proteins for the prognostic histopathological features lymphatic vessel invasion, lymph node metastasis and angioinvasion. This demonstrates the technical feasibility of MALDI-MSI to identify peptide signatures with prognostic value through the workflows used in this study. Abstract: Despite the overall poor prognosis of pancreatic cancer there is heterogeneity in clinical courses of tumors not assessed by conventional risk stratification. This yields the need of additional markers for proper assessment of prognosis and multimodal clinical management. We provide a proof of concept study evaluating the feasibility of Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) to identify specific peptide signatures linked to prognostic parameters of pancreatic cancer. On 18 patients with exocrine pancreatic cancer after tumor resection, MALDI imaging analysis was performed additional to histopathological assessment. Principal component analysis (PCA) was used to explore discrimination of peptide signatures of prognostic histopathological features and receiver operator characteristic (ROC) to identify which specific m/z values are the most discriminative between the prognostic subgroups of patients. Out of 557 aligned m/z values discriminate peptide signatures for the prognostic histopathological features lymphatic vessel invasion (pL, 16 m/z values, eight proteins), nodal metastasis (pN, two m/z values, one protein) and angioinvasion (pV, 4 m/z values, two proteins) were identified. These results yield proof of concept that MALDI-MSI of pancreatic cancer tissue is feasible to identify peptide signatures of prognostic relevance and can augment risk assessment

    Long-distance frequency dissemination with a resolution of 10-17

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    We use a new technique to disseminate microwave reference signals along ordinary optical fiber. The fractional frequency resolution of a link of 86 km in length is 10-17 for a one day integration time, a resolution higher than the stability of the best microwave or optical clocks. We use the link to compare the microwave reference and a CO2/OsO4 frequency standard that stabilizes a femtosecond laser frequency comb. This demonstrates a resolution of 3.10-14 at 1 s. An upper value of the instability introduced by the femtosecond laser-based synthesizer is estimated as 1.10-14 at 1 s
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