322 research outputs found
Formal Safety and Security Assessment of an Avionic Architecture with Alloy
We propose an approach based on Alloy to formally model and assess a system
architecture with respect to safety and security requirements. We illustrate
this approach by considering as a case study an avionic system developed by
Thales, which provides guidance to aircraft. We show how to define in Alloy a
metamodel of avionic architectures with a focus on failure propagations. We
then express the specific architecture of the case study in Alloy. Finally, we
express and check properties that refer to the robustness of the architecture
to failures and attacks.Comment: In Proceedings ESSS 2014, arXiv:1405.055
Journalisme et développement
Les journalistes prĂ©tendent travailler en fonction des attentes supposĂ©es de leurs lecteurs ou auditeurs. En ce sens, on pourrait dire quâils font naturellement acte de communication afin de mieux faire passer lâinformation. La crise que traverse la presse, Ă©conomique mais aussi de confiance, peut faire planer un doute sur lâadĂ©quation entre les propositions des uns et les attentes des autres. Nâest-il pas temps pour les journalistes de prendre en considĂ©ration, tout en lâintĂ©grant dans leur propre logique, les outils de marketing dont disposent les journaux ? Le dĂ©veloppement de la presse (et dâabord sa survie) nâest-il pas Ă ce prix ? Exemple du quotidien rĂ©gional français « Sud Ouest ».Journalists claim to work according to the supposed expectations of their readers or listeners. Thus it could be said that they are involved naturally in communication in order to get over their information. The crisis that the press is currently undergoing, which is economic but which is also a crisis of confidence, might cause some doubt to be shed on the balance between the propositions made by journalists and the expectations of their readers/listeners-Isnât it time that journalists took into consideration the marketing tools that news papers have at their disposal and integrate them into their own logic? Isnât this the price to pay for the development of the press (and first of all, its survival)? The example is the regional daily, « Sud Ouest »
High-voltage-activated Ca2+ currents and the excitability of pyramidal neurons in the hippocampal CA3 subfield in rats depend on corticosterone and time of day
This study tested the time-of-day dependence of the intrinsic postsynaptic properties of hippocampal CA3 pyramidal neurons. High-voltage-activated Ca2+ currents and the Ca2+- and voltage-dependent afterhyperpolarizations were examined in slices of rat brains obtained at four distinct time periods. Just after onset of the dark phase, the steady-state amplitude of the Ca2+ current (-1.24 ± 0.11 nA) was significantly greater (P < 0.03) than that of the light phase (-0.84 ± 0.06 nA). Over the entire time range, the amplitude of the Ca2+ current correlated with plasma corticosterone levels in a U-shaped function. Furthermore, depolarization-induced excitability during the dark phase exhibited an increased spike after depolarization (3.1 ± 0.1 mV) and a slower adaptation of the firing frequency (146 ± 18%). These findings point to a dynamic time-of-day dependence of the CA3 neuronal properties and postsynaptic Ca2+ currents.
Microwave properties of Nd_0.5Sr_0.5MnO_3: a key role of the (x^2-y^2)-orbital effects
Transmittance of the colossal magnetoresistive compound Nd_0.5Sr_0.5MnO_3
showing metal-insulator phase transition has been studied by means of the
submm- and mm-wavelength band spectroscopy. An unusually high transparency of
the material provided direct evidence for the significant suppression of the
coherent Drude weight in the ferromagnetic metallic state. Melting of the
A-type antiferromagnetic states has been found to be responsible for a
considerable increase in the microwave transmission, which was observed at the
transition from the insulating to the metallic phase induced by magnetic field
or temperature. This investigation confirmed a dominant role of the
(x^2-y^2)-orbital degree of freedom in the low-energy optical properties of
Nd_0.5Sr_0.5MnO_3 and other doped manganites with planar (x^2-y^2)-orbital
order, as predicted theoretically. The results are discussed in terms of the
orbital-liquid concept.Comment: 8 pages, 3 figure
Is the formula of Traub still up to date in antemortem blood glucose level estimation?
According to the hypothesis of Traub, also known as the âformula of Traub', postmortem values of glucose and lactate found in the cerebrospinal fluid or vitreous humor are considered indicators of antemortem blood glucose levels. However, because the lactate concentration increases in the vitreous and cerebrospinal fluid after death, some authors postulated that using the sum value to estimate antemortem blood glucose levels could lead to an overestimation of the cases of glucose metabolic disorders with fatal outcomes, such as diabetic ketoacidosis. The aim of our study, performed on 470 consecutive forensic cases, was to ascertain the advantages of the sum value to estimate antemortem blood glucose concentrations and, consequently, to rule out fatal diabetic ketoacidosis as the cause of death. Other biochemical parameters, such as blood 3-beta-hydroxybutyrate, acetoacetate, acetone, glycated haemoglobin and urine glucose levels, were also determined. In addition, postmortem native CT scan, autopsy, histology, neuropathology and toxicology were performed to confirm diabetic ketoacidosis as the cause of death. According to our results, the sum value does not add any further information for the estimation of antemortem blood glucose concentration. The vitreous glucose concentration appears to be the most reliable marker to estimate antemortem hyperglycaemia and, along with the determination of other biochemical markers (such as blood acetone and 3-beta-hydroxybutyrate, urine glucose and glycated haemoglobin), to confirm diabetic ketoacidosis as the cause of deat
Validation of a new automatic smoking machine to study the effects of cigarette smoke in newborn lambs
The aim of this study was to describe the characteristics and validate the use of a new, custom-built automatic smoking machine (ASM), primarily designed to study the effects of an environmental tobacco smoke surrogate (ETS surrogate) exposure in animals of various sizes, including large animals. The equipment includes a programmable ASM coupled to a vented whole body chamber, where animals can be exposed to both mainstream and sidestream smoke. The user-friendly interface allows for full programming of puff volume (1-60 mL), time interval between two puffs (1-60 s) and between two cigarettes (1-60 min). Eight newborn lambs were exposed to either 10 (4 lambs, C10 group) or 20 (4 lambs, C20 group) cigarettes, 8 h per day for 15 days. Four additional control, lambs were exposed to air (C0 group). Weight gain was identical in all three groups of lambs. Urinary cotinine/creatinine ratio increased with the number of cigarettes smoked (C0: 11 ± 7 ng/mg; C10: 961 ± 539 ng/mg; C20: 1821 ± 312 ng/mg), with levels in the C10 and C20 groups in keeping with values published in infants exposed to ETS. Overall, results show that our new ASM is especially well suited for ETS surrogate exposure in non-restrained, non-anaesthetized large animals such as sheep
Changing fish distributions challenge the effective management of European fisheries.
Changes in fish distribution are being observed across the globe. In Europe's Common Fisheries Policy, the share of the catch of each fish stock is split among management areas using a fixed allocation key known as âRelative Stabilityâ: in each management area, member states get the same proportion of the total catch each year. That proportion is largely based on catches made by those member states in the 1970s. Changes in distribution can, therefore, result in a mismatch between quota shares and regional abundances within management areas, with potential repercussions for the status of fish stocks and the fisheries that depend on them. Assessing distribution changes is crucial to ensure adequate management and sustainable exploitation of our fish resources. We analysed scientific survey data using a threeâtiered analytical approach to provide, for the first time, an overview of changes in distribution for 19 northeast Atlantic fish species encompassing 73 commercial stocks over 30 yr. All species have experienced changes in distribution, five of which did so across management areas. A crossâspecies analysis suggested that shifts in areas of suitable thermal habitat, and densityâdependent use of these areas, are at least partly responsible for the observed changes. These findings challenge the current use of relative stability to allocate quotas.acceptedVersio
Copper-NHC-Mediated Semi-Hydrogenation and Hydroboration of Alkynes: Enhanced Catalytic Activity Using Ring-Expanded Carbenes
A series
of two-coordinate copper <i>tert</i>-butoxide
complexes bearing five-, six-, and seven-membered ring N-heterocyclic
carbenes, prepared by protonolysis of (NHC)ÂCuMes with <sup><i>t</i></sup>BuOH, have been used as catalytic precursors in the
semihydrogenation of alkynes with silanes/<sup><i>t</i></sup>BuOH and the hydroboration of alkynes with HBPin. Both processes
proceed with high regioselectivity and show enhancements with six-
and seven-membered ring carbenes
Reconfigurable quantum metamaterials
By coupling controllable quantum systems into larger structures we introduce
the concept of a quantum metamaterial. Conventional meta-materials represent
one of the most important frontiers in optical design, with applications in
diverse fields ranging from medicine to aerospace. Up until now however,
metamaterials have themselves been classical structures and interact only with
the classical properties of light. Here we describe a class of dynamic
metamaterials, based on the quantum properties of coupled atom-cavity arrays,
which are intrinsically lossless, reconfigurable, and operate fundamentally at
the quantum level. We show how this new class of metamaterial could be used to
create a reconfigurable quantum superlens possessing a negative index gradient
for single photon imaging. With the inherent features of quantum superposition
and entanglement of metamaterial properties, this new class of dynamic quantum
metamaterial, opens a new vista for quantum science and technology.Comment: 16 pages, 8 figure
Role of surface roughness in hard x-ray emission from femtosecond laser produced copper plasmas
The hard x-ray emission in the energy range of 30-300 keV from copper plasmas
produced by 100 fs, 806 nm laser pulses at intensities in the range of
10 W cm is investigated. We demonstrate that surface
roughness of the targets overrides the role of polarization state in the
coupling of light to the plasma. We further show that surface roughness has a
significant role in enhancing the x-ray emission in the above mentioned energy
range.Comment: 5 pages, 4 figures, to appear in Phys. Rev.
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