6,534 research outputs found
A Security Monitoring Framework For Virtualization Based HEP Infrastructures
High Energy Physics (HEP) distributed computing infrastructures require
automatic tools to monitor, analyze and react to potential security incidents.
These tools should collect and inspect data such as resource consumption, logs
and sequence of system calls for detecting anomalies that indicate the presence
of a malicious agent. They should also be able to perform automated reactions
to attacks without administrator intervention. We describe a novel framework
that accomplishes these requirements, with a proof of concept implementation
for the ALICE experiment at CERN. We show how we achieve a fully virtualized
environment that improves the security by isolating services and Jobs without a
significant performance impact. We also describe a collected dataset for
Machine Learning based Intrusion Prevention and Detection Systems on Grid
computing. This dataset is composed of resource consumption measurements (such
as CPU, RAM and network traffic), logfiles from operating system services, and
system call data collected from production Jobs running in an ALICE Grid test
site and a big set of malware. This malware was collected from security
research sites. Based on this dataset, we will proceed to develop Machine
Learning algorithms able to detect malicious Jobs.Comment: Proceedings of the 22nd International Conference on Computing in High
Energy and Nuclear Physics, CHEP 2016, 10-14 October 2016, San Francisco.
Submitted to Journal of Physics: Conference Series (JPCS
A versatile scanning photocurrent mapping system to characterize optoelectronic devices based on 2D materials
The investigation of optoelectronic devices based on two-dimensional
materials and their heterostructures is a very active area of investigation
with both fundamental and applied aspects involved. We present a description of
a home-built scanning photocurrent microscope that we have designed and
developed to perform electronic transport and optical measurements of
two-dimensional materials based devices. The complete system is rather
inexpensive (<10000 EUR) and it can be easily replicated in any laboratory. To
illustrate the setup we measure current-voltage characteristics, in dark and
under global illumination, of an ultra-thin PN junction formed by the stacking
of an n-doped few-layer MoS2 flake onto a p-type MoS2 flake. We then acquire
scanning photocurrent maps and by mapping the short circuit current generated
in the device under local illumination we find that at zero bias the
photocurrent is generated mostly in the region of overlap between the n-type
and p-type flakes.Comment: 9 pages, 3 figures, 1 table, supporting informatio
Low frequency noise due to magnetic inhomogeneities in submicron FeCoB/MgO/FeCoB magnetic tunnel junctions
We report on room temperature low frequency noise due to magnetic
inhomogeneities/domain walls (MI/DWs) in elliptic submicron FeCoB/MgO/FeCoB
magnetic tunnel junctions with an area between 0.0245 and 0.0675{\mu}m2. In the
smaller area junctions we found an unexpected random telegraph noise (RTN1),
deeply in the parallel state, possibly due to stray field induced MI/DWs in the
hard layer. The second noise source (RTN2) is observed in the antiparallel
state for the largest junctions. Strong asymmetry of RTN2 and of related
resistance steps with current indicate spin torque acting on the MI/DWs in the
soft layer at current densities below 5x10^5 A/cm2.Comment: 12 pages, 4 figure
Modelo de atención por parte de la secretaria de educación del distrito en el marco del restablecimiento de derechos a la población indígena embera en situación de desplazamiento
Actualmente, en la ciudad de Bogotá residen a causa del fenómeno de desplazamiento 864 indígenas de la etnia Embera, esta población, por su situación de desplazamiento, no se encuentra reportada como comunidad indígena reconocida oficialmente establecida en la ciudad. Tras realizar una recopilación de la normatividad vigente respecto a la atención integral a personas en situación de desplazamiento referente al tema de educación y etno-educación, se definió un procedimiento para integrar a la población Indígena en situación de desplazamiento al sistema educativo oficial del distrito y las pautas que deberá cumplir una institución educativa para garantizar el derecho a la educación a la población vulnerable. Producto de todo esto se determina la forma en que la Secretaria de Educación garantizara el acceso al sistema educativo oficial a las comunidades indígenas en situación de desplazamiento con una educación incluyente, diferenciada y especifica de acuerdo al requerimiento expresado por parte de la corte constitucional, los órganos internacionales y las necesidades reales de la población indígena Ember
Achradina pulchra, a Unique Dinoflagellate (Amphilothales, Dinophyceae) with a Radiolarian-like Endoskeleton of Celestite (Strontium Sulfate)
We examined the planktonic dinoflagellate Achradina pulchra by light and scanning electron microscopies from the South and North Atlantic oceans. The basket-like skeleton has been interpreted as a thick cell covering or pellicle of organic composition, or as a siliceous endoskeleton. The skeleton of Achradina is known only from fresh material, being absent in preserved samples, sediments or the fossil record. X-ray microanalysis revealed that the endoskeleton of Achradina is composed of celestite (strontium sulfate) with traces of barite (barium sulfate), two minerals that readily dissolve after cell death. To date, Acantharia and polycystine radiolarians (Retaria) were the only known organisms with a skeleton of this composition. We can now add a dinoflagellate to the list of such mineralized skeletons, which influence on the biogeochemical fluxes of strontium and barium in the oceans. Moreover, we provided the first molecular data for a skeleton-bearing dinoflagellate. Molecular phylogeny based on the SSU rRNA gene sequences revealed that Achradina and several environmental clones branched as an independent lineage within the short-branching dinokaryotic dinoflagellates. To date, seven clades of dinokaryotic dinoflagellates are known living as symbionts in the endoplasm of Acantharia and polycystine radiolarians. Because celestite built skeletons were unknown outside radiolarians, we suggested that the ancestors of Achradina acquired the genes implicated in the deposition of strontium and barium from radiolarian hosts though a horizontal gene transfer event between microbial eukaryotes
TCT-386 Global risk score for choosing the best revascularization strategy in patients with unprotected left main stenosis
Modernista, 1920.Primer pla d'edifici unifamiliar.De planta baixa,
planta semisoterrani i un cos de garatge
adossat.Les obertures situen a les llindes
uns motllurats i sinuosos motius escultòrics.
Un element de ceràmica divideix els baixos
del coronament
A strain tunable single-layer MoS2 photodetector
Strain engineering, which aims to tune the bandgap of a semiconductor by the
application of strain, has emerged as an interesting way to control the
electrical and optical properties of two-dimensional (2D) materials. Apart from
the changes in the intrinsic properties of 2D materials, the application of
strain can be also used to modify the characteristics of devices based on them.
In this work, we study flexible and transparent photodetectors based on
single-layer MoS2 under the application of biaxial strain. We find that by
controlling the level of strain, we can tune the photoresponsivity (by 2-3
orders of magnitude), the response time (from <80 ms to 1.5 s) and the spectral
bandwidth (with a gauge factor of 135 meV/% or 58 nm/%) of the device.Comment: 3 main text figures and 12 supporting information figure
Transcriptional profiling reveals functional links between RasGrf1 and Pttg1 in pancreatic beta cells
Background: Our prior characterization of RasGrf1 deficient mice uncovered significant defects in pancreatic islet count and size as well as beta cell development and signaling function, raising question about the mechanisms linking RasGrf1 to the generation of those"pancreatic" phenotypes. Results: Here, we compared the transcriptional profile of highly purified pancreatic islets from RasGrf1 KO mice to that of WT control animals using commercial oligonucleotide microarrays. RasGrf1 elimination resulted in differential gene expression of numerous components of MAPK- and Calcium-signaling pathways,suggesting a relevant contribution of this GEF to modulation of cellular signaling in the cell lineages integrating the pancreatic islets. Whereas the overall transcriptional profile of pancreatic islets was highly specific in comparison to other organs of the same KO mice, a significant specific repression of Pttg1 was a common transcriptional alteration shared with other tissues of neuroectodermal origin. This observation,together with the remarkable pancreatic phenotypic similarities between RasGrf1 KO and Pttg1 KO mice suggested the possibility of proximal functional regulatory links between RasGrf1 and Pttg1 in pancreatic cell lineages expressing these proteins. Analysis of the mPttg1 promoter region identified specific recognition sites for numerous transcription factors which were also found to be differentially expressed in RasGrf1 KO pancreatic islets and are known to be relevant for Ras-ERK signaling as well as beta cell function. Reporter luciferase assays in BT3 insulinoma cells demonstrated the ability of RasGrf1 to modulate mPttg1 promoter activity through ERK-mediated signals. Analysis of the phenotypic interplay between RasGrf1 and Pttg1 in double knockout RasGrf1/Pttg1 mice showed that combined elimination of the two loci resulted in dramatically reduced values of islet and beta cell count and glucose homeostasis function which neared those measured in single Pttg1 KO mice and were significantly lower than those observed in individual RasGrf1 KO mice. Conclusions: The specific transcriptional profile and signaling behavior of RasgGrf1 KO pancreatic islets, together with the dominance of Pttg1 over RasGrf1 with regards to the generation of these phenotypes in mouse pancreas, suggest that RasGrf1 is an important upstream component of signal transduction pathways regulating Pttg1 expression and controlling beta cell development and physiological response
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