495 research outputs found
Electronic Trap Microscopy - A New Mode for Scanning Electron Microscopy (SEM)
Insulating layers on conducting substrate are investigated by means of secondary electron field emission SEFE in a digital SEM. The kinetics of charge storage and release with time and temperature are controlled and recorded by an external computer.The evaluation is performed pixel-wise with respect to electronic trap concentration nt0, trap capture cross section σc and thermal activation energy Et. Mapping of these trap parameters indicates hidden inhomogenities, defects and pre-treatments of the dielectric layers as well as the pattern of thermal bleaching and release of electrons. The latter ones appear as inhomogeneous processes starting with blinking centers and increasing their concentration with time and temperature
Proving Craig and Lyndon Interpolation Using Labelled Sequent Calculi
We have recently presented a general method of proving the fundamental
logical properties of Craig and Lyndon Interpolation (IPs) by induction on
derivations in a wide class of internal sequent calculi, including sequents,
hypersequents, and nested sequents. Here we adapt the method to a more general
external formalism of labelled sequents and provide sufficient criteria on the
Kripke-frame characterization of a logic that guarantee the IPs. In particular,
we show that classes of frames definable by quantifier-free Horn formulas
correspond to logics with the IPs. These criteria capture the modal cube and
the infinite family of transitive Geach logics
Explicit Evidence Systems with Common Knowledge
Justification logics are epistemic logics that explicitly include
justifications for the agents' knowledge. We develop a multi-agent
justification logic with evidence terms for individual agents as well as for
common knowledge. We define a Kripke-style semantics that is similar to
Fitting's semantics for the Logic of Proofs LP. We show the soundness,
completeness, and finite model property of our multi-agent justification logic
with respect to this Kripke-style semantics. We demonstrate that our logic is a
conservative extension of Yavorskaya's minimal bimodal explicit evidence logic,
which is a two-agent version of LP. We discuss the relationship of our logic to
the multi-agent modal logic S4 with common knowledge. Finally, we give a brief
analysis of the coordinated attack problem in the newly developed language of
our logic
HIV-1 Tat causes cognitive deficits and selective loss of parvalbumin, somatostatin, and neuronal nitric oxide synthase expressing hippocampal CA1 interneuron subpopulations
Memory deficits are characteristic of HIV-associated neurocognitive disorders (HAND) and co-occur with hippocampal pathology. The HIV-1 transactivator of transcription (Tat), a regulatory protein, plays a significant role in these events, but the cellular mechanisms involved are poorly understood. Within the hippocampus, diverse populations of interneurons form complex networks; even subtle disruptions can drastically alter synaptic output, resulting in behavioral dysfunction. We hypothesized that HIV-1 Tat would impair cognitive behavior and injure specific hippocampal interneuron subtypes. Male transgenic mice that inducibly expressed HIV-1 Tat (or non-expressing controls) were assessed for cognitive behavior or had hippocampal CA1 subregions evaluated via interneuron subpopulation markers. Tat exposure decreased spatial memory in a Barnes maze and mnemonic performance in a novel object recognition test. Tat reduced the percentage of neurons expressing neuronal nitric oxide synthase (nNOS) without neuropeptide Y immunoreactivity in the stratum pyramidale and the stratum radiatum, parvalbumin in the stratum pyramidale, and somatostatin in the stratum oriens, which are consistent with reductions in interneuron-specific interneuron type 3 (IS3), bistratified, and oriens-lacunosum-moleculare interneurons, respectively. The findings reveal that an interconnected ensemble of CA1 nNOS-expressing interneurons, the IS3 cells, as well as subpopulations of parvalbumin- and somatostatin-expressing interneurons are preferentially vulnerable to HIV-1 Tat. Importantly, the susceptible interneurons form a microcircuit thought to be involved in feedback inhibition of CA1 pyramidal cells and gating of CA1 pyramidal cell inputs. The identification of vulnerable CA1 hippocampal interneurons may provide novel insight into the basic mechanisms underlying key functional and neurobehavioral deficits associated with HAND
A Semantic Completeness Proof for TaMeD
International audienceDeduction modulo is a theoretical framework designed to introduce computational steps in deductive systems. This approach is well suited to automated theorem proving and a tableau method for first-order classical deduction modulo has been developed. We reformulate this method and give an (almost constructive) semantic completeness proof. This new proof allows us to extend the completeness theorem to several classes of rewrite systems used for computations in deduction modulo. We are then able to build a counter-model when a proof fails for these systems
Octahedral conversion of a-SiO2-host matrix by pulsed ion implantation
This is the abstract. The results of measurements of X-ray photoelectron
spectra (XPS) of a-SiO2-host material after pulsed implantation with [Mn+] and
[Co+, Mn+]-ions as well as DFT-calculations are presented. The low-energy shift
is found in XPS Si 2p and O 1s core-levels of single [Mn+] and dual [Co+, Mn+]
pulsed ion-implanted a-SiO2 (E = 30 keV, D = 2*10^17 cm^-2) with respect to
those of untreated a-SiO2.The similar changes are found in XPS Si 2p and O 1s
of stishovite compared to those of quartz. This means that the pulsed
ion-implantation induces the local high pressure effect which leads to an
appearance of SiO6-structural units in alpha-SiO2 host, forming
"stishovite-like" local atomic structure. This process can be described within
electronic bonding transition from the four-fold "quartz-like" to six-fold
"stishovite-like" high-pressure phase in SiO2 host-matrix. It is found that
such octahedral conversion depends on the fluence and starts with doses higher
than D = 3*10^16 cm^-2.Comment: 15 pages, 6 figures, 1 table, accepted in phys. stat. solidi (b
Towards a Proof Theory of G\"odel Modal Logics
Analytic proof calculi are introduced for box and diamond fragments of basic
modal fuzzy logics that combine the Kripke semantics of modal logic K with the
many-valued semantics of G\"odel logic. The calculi are used to establish
completeness and complexity results for these fragments
Defects and localized states in silica layers implanted with lead ions
The luminescence of silica films and glasses implanted with Pb+ ions was studied by means of time-resolved photoluminescence spectroscopy under synchrotron excitation. The ion-modified silica layers are "metal- dielectrics" composites the oxide part of which is represented by amorphous micro-heterogeneous phase with variable Pb2+ions. Two groups of emission centers are identified: such as: (1) radiation-induced oxygen-deficient centers (ODCs) and non-bridging oxygen atoms (NBOs) in the SiO2 matrix and (2) localized electronic states (LS) of the amorphous lead-silicate phase. © 2014 Elsevier B.V
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