137 research outputs found
Detecting Anomalous Network Communication Patterns Using Graph Convolutional Networks
To protect an organizations' endpoints from sophisticated cyberattacks,
advanced detection methods are required. In this research, we present
GCNetOmaly: a graph convolutional network (GCN)-based variational autoencoder
(VAE) anomaly detector trained on data that include connection events among
internal and external machines. As input, the proposed GCN-based VAE model
receives two matrices: (i) the normalized adjacency matrix, which represents
the connections among the machines, and (ii) the feature matrix, which includes
various features (demographic, statistical, process-related, and Node2vec
structural features) that are used to profile the individual nodes/machines.
After training the model on data collected for a predefined time window, the
model is applied on the same data; the reconstruction score obtained by the
model for a given machine then serves as the machine's anomaly score.
GCNetOmaly was evaluated on real, large-scale data logged by Carbon Black EDR
from a large financial organization's automated teller machines (ATMs) as well
as communication with Active Directory (AD) servers in two setups: unsupervised
and supervised. The results of our evaluation demonstrate GCNetOmaly's
effectiveness in detecting anomalous behavior of machines on unsupervised data
Mice Deficient in Ribosomal Protein S6 Phosphorylation Suffer from Muscle Weakness that Reflects a Growth Defect and Energy Deficit
BACKGROUND: Mice, whose ribosomal protein S6 cannot be phosphorylated due to replacement of all five phosphorylatable serine residues by alanines (rpS6(P-/-)), are viable and fertile. However, phenotypic characterization of these mice and embryo fibroblasts derived from them, has established the role of these modifications in the regulation of the size of several cell types, as well as pancreatic beta-cell function and glucose homeostasis. A relatively passive behavior of these mice has raised the possibility that they suffer from muscle weakness, which has, indeed, been confirmed by a variety of physical performance tests. METHODOLOGY/PRINCIPAL FINDINGS: A large variety of experimental methodologies, including morphometric measurements of histological preparations, high throughput proteomic analysis, positron emission tomography (PET) and numerous biochemical assays, were used in an attempt to establish the mechanism underlying the relative weakness of rpS6(P-/-) muscles. Collectively, these experiments have demonstrated that the physical inferiority appears to result from two defects: a) a decrease in total muscle mass that reflects impaired growth, rather than aberrant differentiation of myofibers, as well as a diminished abundance of contractile proteins; and b) a reduced content of ATP and phosphocreatine, two readily available energy sources. The abundance of three mitochondrial proteins has been shown to diminish in the knockin mouse. However, the apparent energy deficiency in this genotype does not result from a lower mitochondrial mass or compromised activity of enzymes of the oxidative phosphorylation, nor does it reflect a decline in insulin-dependent glucose uptake, or diminution in storage of glycogen or triacylglycerol (TG) in the muscle. CONCLUSIONS/SIGNIFICANCE: This study establishes rpS6 phosphorylation as a determinant of muscle strength through its role in regulation of myofiber growth and energy content. Interestingly, a similar role has been assigned for ribosomal protein S6 kinase 1, even though it regulates myoblast growth in an rpS6 phosphorylation-independent fashion
Gravitational Quenching in Massive Galaxies and Clusters by Clumpy Accretion
We consider a simple gravitational-heating mechanism for the long-term
quenching of cooling flows and star formation in massive dark-matter haloes
hosting ellipticals and clusters. The virial shock heating in haloes >10^12 Mo
triggers quenching in 10^12-13 Mo haloes (Birnboim, Dekel & Neistein 2007). We
show that the long-term quenching in haloes >Mmin~7x10^12 Mo could be due to
the gravitational energy of cosmological accretion delivered to the inner-halo
hot gas by cold flows via ram-pressure drag and local shocks. Mmin is obtained
by comparing the gravitational power of infall into the potential well with the
overall radiative cooling rate. The heating wins if the gas inner density cusp
is not steeper than r^-0.5 and if the masses in the cold and hot phases are
comparable. The effect is stronger at higher redshifts, making the maintenance
easier also at later times. Clumps >10^5 Mo penetrate to the inner halo with
sufficient kinetic energy before they disintegrate, but they have to be <10^8
Mo for the drag to do enough work in a Hubble time. Pressure confined ~10^4K
clumps are stable against their own gravity and remain gaseous once below the
Bonnor-Ebert mass ~10^8 Mo. They are also immune to tidal disruption. Clumps in
the desired mass range could emerge by thermal instability in the outer halo if
the conductivity is not too high. Alternatively, such clumps may be embedded in
dark-matter subhaloes if the ionizing flux is ineffective, but they separate
from their subhaloes by ram pressure before entering the inner halo. Heating by
dynamical friction becomes dominant for massive satellites, which can
contribute up to one third of the total gravitational heating. We conclude that
gravitational heating by cosmological accretion is a viable alternative to AGN
feedback as a long-term quenching mechanism.Comment: 24 pages, 20 figures, some improvements, MNRAS accepted versio
Gravitational Quenching in Massive Galaxies and Clusters by Clumpy Accretion
We consider a simple gravitational-heating mechanism for the long-term
quenching of cooling flows and star formation in massive dark-matter haloes
hosting ellipticals and clusters. The virial shock heating in haloes >10^12 Mo
triggers quenching in 10^12-13 Mo haloes (Birnboim, Dekel & Neistein 2007). We
show that the long-term quenching in haloes >Mmin~7x10^12 Mo could be due to
the gravitational energy of cosmological accretion delivered to the inner-halo
hot gas by cold flows via ram-pressure drag and local shocks. Mmin is obtained
by comparing the gravitational power of infall into the potential well with the
overall radiative cooling rate. The heating wins if the gas inner density cusp
is not steeper than r^-0.5 and if the masses in the cold and hot phases are
comparable. The effect is stronger at higher redshifts, making the maintenance
easier also at later times. Clumps >10^5 Mo penetrate to the inner halo with
sufficient kinetic energy before they disintegrate, but they have to be <10^8
Mo for the drag to do enough work in a Hubble time. Pressure confined ~10^4K
clumps are stable against their own gravity and remain gaseous once below the
Bonnor-Ebert mass ~10^8 Mo. They are also immune to tidal disruption. Clumps in
the desired mass range could emerge by thermal instability in the outer halo if
the conductivity is not too high. Alternatively, such clumps may be embedded in
dark-matter subhaloes if the ionizing flux is ineffective, but they separate
from their subhaloes by ram pressure before entering the inner halo. Heating by
dynamical friction becomes dominant for massive satellites, which can
contribute up to one third of the total gravitational heating. We conclude that
gravitational heating by cosmological accretion is a viable alternative to AGN
feedback as a long-term quenching mechanism.Comment: 24 pages, 20 figures, some improvements, MNRAS accepted versio
Mice deficient in ribosomal protein S6 phosphorylation suffer from muscle weakness that reflects a growth defect and energy deficit. PLoS One
Abstract Background: Mice, whose ribosomal protein S6 cannot be phosphorylated due to replacement of all five phosphorylatable serine residues by alanines (rpS6 P2/2 ), are viable and fertile. However, phenotypic characterization of these mice and embryo fibroblasts derived from them, has established the role of these modifications in the regulation of the size of several cell types, as well as pancreatic b-cell function and glucose homeostasis. A relatively passive behavior of these mice has raised the possibility that they suffer from muscle weakness, which has, indeed, been confirmed by a variety of physical performance tests
An absent presence: Separated child migrants’ caring practices and the fortified neoliberal state
This paper explores the ambivalent positioning of separated child migrants in the UK with a focus on the care that they provide for each other. Drawing on interview data with state and non-state adult stakeholders involved in the immigration-welfare nexus, we consider how children’s care practices are viewed and represented. We argue that separated children’s caring practices assume an absent presence in the discourses mobilised by these actors: either difficult to articulate or represented in negative and morally-laden terms, reflective of the UK’s 'hostile environment' towards migrants and advanced capitalist constructions of childhood. Such an examination sheds light on the complex state attempts to manage the care and migration regimes, and the way that care can serve as a way of making and marking inclusions and exclusions. Here we emphasise the political consequences for separated child migrants in an age of neoliberal state retrenchment from public provision of care and rising xenophobic nationalism
DeepSearch: A Simple and Effective Blackbox Attack for Deep Neural Networks
Although deep neural networks have been very successful in
image-classification tasks, they are prone to adversarial attacks. To generate
adversarial inputs, there has emerged a wide variety of techniques, such as
black- and whitebox attacks for neural networks. In this paper, we present
DeepSearch, a novel fuzzing-based, query-efficient, blackbox attack for image
classifiers. Despite its simplicity, DeepSearch is shown to be more effective
in finding adversarial inputs than state-of-the-art blackbox approaches.
DeepSearch is additionally able to generate the most subtle adversarial inputs
in comparison to these approaches
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