6,471 research outputs found
OS diversity for intrusion tolerance: Myth or reality?
One of the key benefits of using intrusion-tolerant systems is the possibility of ensuring correct behavior in the presence of attacks and intrusions. These security gains are directly dependent on the components exhibiting failure diversity. To what extent failure diversity is observed in practical deployment depends on how diverse are the components that constitute the system. In this paper we present a study with operating systems (OS) vulnerability data from the NIST National Vulnerability Database. We have analyzed the vulnerabilities of 11 different OSes over a period of roughly 15 years, to check how many of these vulnerabilities occur in more than one OS. We found this number to be low for several combinations of OSes. Hence, our analysis provides a strong indication that building a system with diverse OSes may be a useful technique to improve its intrusion tolerance capabilities
Biological performance of natural-based polymers for tissue engineering scaffolding
[Excerpt] One of the open issues in the Tissue Engineering area is whether scaffolds are needed at all to regenerate many tissue defects. This is a fundamental question that may be answered by providing
clear evidence of success by scaffold-less tissue regeneration strategies. In its absence, many groups within this research community are focused in the development of scaffold-dependent strategies.
Natural-based biomaterials have been proposed and explored to meet the requirements of many applications in the Tissue Engineering and Regenerative Medicine. Among the important characteristics of those biomaterials it should be highlighted the easy biodegradation by normal metabolic pathways, the low cytotoxicity and low immunogenic reaction upon implantation and the myriad of properties obtained by combination of those materials with other biodegradable polymers. This later strategy has been
pursued in our lab in the quest to obtain scaffolds that effectively help, assist and drive cells to regenerate connective tissues. [...]info:eu-repo/semantics/publishedVersio
Minimally Extended Left-Right Symmetric Model for Dark Matter with U(1) Portal
A minimal extension of the left-right symmetric model for neutrino masses
that includes a vector-like singlet fermion dark matter (DM) is presented with
the DM connected to the visible sector via a gauged U(1) portal. We discuss the
symmetry breaking in this model and calculate the mass and mixings of the extra
heavy neutral gauge boson at the TeV scale. The extra gauge boson can decay to
both standard model particles as well to dark matter. We calculate the relic
density of the singlet fermion dark matter and its direct detection cross
section and use these constraints to obtain the allowed parameter range for the
new gauge coupling and the dark matter mass.Comment: 19 pages, 8 figure
INJECTABLE HYBRID SYSTEM FOR STRONTIUM LOCAL DELIVERY TO PROMOTE BONE REGENERATION
In bone tissue regeneration strategies, injectable bone substitutes are very attractive since they can
be applied with minimally invasive surgical procedures and can perfectly fill irregular defects created
in cases of trauma, infection or tumor resection. These materials must combine adequate mechanical
properties with the ability to induce new bone formation. Incorporating strontium (Sr) in bone
substitute biomaterials may be a strategy to achieve high Sr concentrations, not in a systemic but in
a local environment, taking advantage of the osteoanabolic and anti-osteoclastic activity of Sr, for
the enhancement of new bone formation. In this context, the aim of the present work was to
evaluate the response of a Sr-hybrid injectable system for bone regeneration, designed by our
group, consisting of hydroxyapatite microspheres doped with Sr and an alginate vehicle crosslinked in
situ with Sr, in an in vivo scenario. Two different animal models were used, rat (Wistar) and sheep
(Merino Branco) critical sized bone defect. Non Sr-doped similar materials (Ca-hybrid) or empty
defects were used as control. Sr-hybrid system led to an increased bone formation in both center
and periphery of a rat critical sized defect compared to a non Sr–doped similar system, where new
bone formation was restricted to the periphery. Moreover newly formed bone was identified as early
as one week after its implantation in a sheep model. After eight weeks, the bone surrounded the
microspheres, both in the periphery and in the center of the defect. Most importantly, the hybrid
system provided a scaffold for cell migration and tissue ingrowth and offered structural support, as
observed in both models. The effective improvement of local bone formation suggests that this might
be a promising approach for bone regeneration, especially in osteoporotic conditions
Prediction of stiffness from orientation data of glass reinforced injection moldings
The complex thermo-mechanical process developing in
injection molding leads to through-thickness and point to
point variation of fiber orientation. It is not economically
viable to characterize experimentally the variation of fiber
orientation. Thus, efforts have been put into modeling the
fiber orientation in injection molding. Some commercially
available programs already allow the prediction of fiber
orientation distribution in moldings.
If the fiber orientation field is known it is possible to
calculate the major elastic properties, which can be input
into finite-element structural analysis codes to predict
product performance.
That approach was followed in this work to compare the
experimental flexure behavior of glass fiber reinforced
polycarbonate injection molded discs with predictions
obtained from FEM simulations. The data used in the FEM
code was calculated from the fiber orientation data
predicted using the software C-Mold.(undefined
Análise exploratória de dados de monitoramento dos animais em um sistema de integração lavoura-pecuária.
Resumo: A aplicação dos preceitos da Agricultura de Precisão em um sistema de Integração Lavoura-Pecuária (ILP) envolve um grau de dificuldade maior devido ao número de fatores envolvidos e a presença da componente animal. Variáveis como a mobilidade, pisoteio, dejeções dos animais e zonas preferenciais podem impactar o sistema e devem ser consideradas. O objetivo deste trabalho é realizar uma análise exploratória dos dados de monitoramento de animais em um sistema ILP. Os dados foram obtidos por aparelhos GPS afixados em animais do rebanho e complementados por observações de campo. São apresentados mapas derivados da aplicação do estimador de intensidade Kernel para situações distintas e levantadas hipóteses sobre os comportamentos dos animais
Análise exploratória de dados de monitoramento dos animais em um sistema de integração lavoura-pecuária.
Resumo: A aplicação dos preceitos da Agricultura de Precisão em um sistema de Integração Lavoura-Pecuária (ILP) envolve um grau de dificuldade maior devido ao número de fatores envolvidos e a presença da componente animal. Variáveis como a mobilidade, pisoteio, dejeções dos animais e zonas preferenciais podem impactar o sistema e devem ser consideradas. O objetivo deste trabalho é realizar uma análise exploratória dos dados de monitoramento de animais em um sistema ILP. Os dados foram obtidos por aparelhos GPS afixados em animais do rebanho e complementados por observações de campo. São apresentados mapas derivados da aplicação do estimador de intensidade Kernel para situações distintas e levantadas hipóteses sobre os comportamentos dos animais
Correlação entre medidas de condutividade elétrica em sistema de integração lavoura-pecuária.
Apsul América
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