2,877 research outputs found
An n-sided polygonal model to calculate the impact of cyber security events
This paper presents a model to represent graphically the impact of cyber
events (e.g., attacks, countermeasures) in a polygonal systems of n-sides. The
approach considers information about all entities composing an information
system (e.g., users, IP addresses, communication protocols, physical and
logical resources, etc.). Every axis is composed of entities that contribute to
the execution of the security event. Each entity has an associated weighting
factor that measures its contribution using a multi-criteria methodology named
CARVER. The graphical representation of cyber events is depicted as straight
lines (one dimension) or polygons (two or more dimensions). Geometrical
operations are used to compute the size (i.e, length, perimeter, surface area)
and thus the impact of each event. As a result, it is possible to identify and
compare the magnitude of cyber events. A case study with multiple security
events is presented as an illustration on how the model is built and computed.Comment: 16 pages, 5 figures, 2 tables, 11th International Conference on Risks
and Security of Internet and Systems, (CRiSIS 2016), Roscoff, France,
September 201
Vacuum-field Rabi oscillations in atomically doped carbon nanotubes
We report a strictly non-exponential spontaneous decay dynamics of an excited
two-level atom placed inside or at different distances outside a carbon
nanotube. This is the result of strong non-Markovian memory effects arising
from the rapid frequency variation of the photonic density of states near the
nanotube. The system exhibits vacuum-field Rabi oscillations when the atom is
close enough to the nanotube surface and the atomic transition frequency is in
the vicinity of the resonance of the photonic density of states.Comment: 4 pages, 2 figure
Quantifying Wetting Dynamics with Triboelectrification
Wetting is often perceived as an intrinsic surface property of materials, but
determining its evolution is complicated by its complex dependence on roughness
across the scales. The Wenzel state, where liquids have intimate contact with
the rough substrate, and the Cassie-Baxter state, where liquids sit onto air
pockets formed between asperities, are only two states among the plethora of
wetting behaviors. Furthermore, transitions from the Cassie-Baxter to the
Wenzel state dictate completely different surface performance, such as
anti-contamination, anti-icing, drag reduction etc.; however, little is known
about how transition occurs during time between the several wetting modes. In
this paper, we show that wetting dynamics can be accurately quantified and
tracked using solid-liquid triboelectrification. Theoretical underpinning
reveals how surface micro-/nano-geometries regulate stability/infiltration,
also demonstrating the generality of our theoretical approach in understanding
wetting transitions.Comment: Both Main and SI uploaded in a single fil
Thin Film Rupture from the Atomic Scale
The retraction of thin films, as described by the Taylor-Culick (TC) theory,
is subject to widespread debate, particularly for films at the nanoscale. We
use non-equilibrium molecular dynamics simulations to explore the validity of
the assumptions used in continuum models, by tracking the evolution of holes in
a film. By deriving a new mathematical form for the surface shape and
considering a locally varying surface tension at the front of the retracting
film, we reconcile the original theory with our simulation data to recover a
corrected TC speed valid at the nanoscale
The Biological Impact of Concurrent Exposure to Metallic Nanoparticles and a Static Magnetic Field
The rapid advancement of technology has led to an exponential increase of both nanomaterial and magnetic field utilization in applications spanning a variety of sectors. While extensive work has focused on the impact of these two variables on biological systems independently, the existence of any synergistic effects following concurrent exposure has yet to be investigated. This study sought to ascertain the induced alterations to the stress and proliferation responses of the human adult low calcium, high temperature keratinocyte (HaCaT) cell line by the application of a static magnetic field (approximately 0.5 or 30âmT) in conjunction with either gold or iron oxide nanoparticles for a duration of 24âh. By evaluating targets at a cellular, protein, and genetic level a complete assessment of the HaCaT response was generated. A magnetic field-dependent proliferative effect was found (âŒ15%), which correlated with a decrease in reactive oxygen species and a simultaneous increase in ki67 expression, all occurring independently of nanoparticle presence. Furthermore, the application of a static magnetic field was able to counteract the cellular stress response induced by nanoparticle exposure through a combination of decreased reactive oxygen species production and modification of gene regulation. Therefore, we conclude that while these variables each introduce the potential to uniquely influence physiological events, no negative synergistic reactions were identified
Induction of apoptotic lesions in liver and lymphoid tissues and modulation of cytokine mRNA expression by acute exposure to deoxynivalenol in piglets
Six 1-month-old piglets were intravenously injected with deoxynivalenol (DON) at the concentration of 1 mg/kg body weight, with three pigs each necropsied at 6 and 24 h post-injection (PI) for investigation of hepatotoxicity and immunotoxicity with special attention to apoptotic changes and cytokine mRNA expression. Histopathological examination of the DON-injected pigs revealed systemic apoptosis of lymphocytes in lymphoid tissues and hepatocytes. Apoptosis of lymphocytes and hepatocytes was confirmed by the TdT-mediated dUTP-biotin nick end-labeling (TUNEL) method and immunohistochemical staining against single-stranded DNA and cleaved caspase-3. The number of TUNEL-positive cells in the thymus and Peyer's patches of the ileum was increased at 24 h PI compared to 6 h PI, but the peak was at 6 h PI in the liver. The mRNA expression of interleukin (IL)-1ÎČ, IL-6, IL-18, and tumor necrosis factor (TNF)-α in the spleen, thymus and mesenteric lymph nodes were determined by semi-quantitative RT-PCR, and elevated expression of IL-1ÎČ mRNA at 6 h PI and a decrease of IL-18 mRNA at 24 h PI were observed in the spleen. IL-1ÎČ and IL-6 mRNA expressions increased significantly at 6 h PI in the thymus, but TNF-α decreased at 6 h PI in the mesenteric lymph nodes. These results show the apoptosis of hepatocytes suggesting the hepatotoxic potential of DON, in addition to an immunotoxic effect on the modulation of proinflammatory cytokine genes in lymphoid organs with extensive apoptosis of lymphocytes induced by acute exposure to DON in pigs
The mediating effect of the cyberchondria and anxiety sensitivity in the association between problematic internet use, metacognition beliefs, and fear of COVID-19 among Iranian online population
With the rapid growth of the novel coronavirus disease 2019 (COVID-19), individuals may try to find related medical information using the internet to overcome their fears. Under such circumstances, individuals with the features of cyberchondria, anxiety sensitivity, and metacognitive beliefs in negative thoughts may suffer more fears than those without these features. Therefore, the present study proposed a model to understand the associations between problematic internet use (PIU), cyberchondria, anxiety sensitivity, metacognition beliefs, and fear of COVID-19. Utilizing a cross-sectional online survey, 651 Iranians completed the following psychometric scales: Metacognition Questionnaire-30 (MCQ-30), Anxiety Sensitivity Questionnaire (ASI), Cyberchondria Severity Scale-Short Form (CSS-12), Fear of COVID-19 Scale (FCVâ19S), and Generalized Problematic Internet Use Scale (GPIUS). Structural equation modeling (SEM) was used to assess the proposed model via several fit indices. The indices include Tucker-Lewis index (TLI), comparative fit index (CFI), standardized root mean square residual (SRMR), and root mean square error of approximation (RMSEA). The fit indices (CFI = 0.948, TLI = 0.938, RMSEA = 0.053, and SRMR = 0.001) indicated the good fit between the data and the proposed model. Moreover, fear of COVID-19 was significantly and directly predicted by cyberchondria (ÎČ = 0.479, p < .001) and anxiety sensitivity (ÎČ = 0.286, p < .001). The relationship between PIU and cyberchondria with fear of COVID-19 was mediated significantly by anxiety sensitivity and metacognitive beliefs. Because fear of COVID-19 was found to be significantly associated with cyberchondria and anxiety sensitivity, healthcare providers may want to provide additional support for those with cyberchondria and anxiety sensitivity tendencies
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