870 research outputs found
Phosphoinositide hydrolysis mediated by H1 receptors in autoimmune myocarditis mice
Stimulation of phosphoinositide hydrolysis in myocardium from autoimmune myocarditis mice by ThEA and histamine was assayed. Myocardium from autoimmune heart, but not the normal forms, specifically increased phosphoinositide turnover in the presence of histaminergic agonists. This increment was blocked by a specific H1 antagonist mepyramine and to the same extent by the phospholipase C inhibitor NCDC. By using a binding assay H1 histaminergic receptors were detected in autoimmune heart membrane preparations, but this was not observed in normal heart. These data suggest that autoimmune myocardium expressed a functional H1 receptor that could involve a distinctive mechanism operating in the disease
Museum Websites of the First Wave: The rise of the virtual museum
In this paper, we analyse trends of the first wave of museum websites (from the 1990s to the early 2000s) to understand how the characteristics of the Internet (specifically the World Wide Web), of museum staff, and museum audiences shaped the adoption of technology and new forms of participation and what they can tell us about engagement for museums of the future. The early development of online museum resources parallels the development of the EVA conference, which was establishing itself at a similar time
Cholinoceptor Activation Subserving the Effects of Interferon Gamma on the Contractility of Rat Ileum
Recombinant rat interferon Îł stimulated the contractility of
isolated rat ileum at doses of 4â12 units/ml. Muscarinic
cholinoceptors were involved, as treatment of the tissue with
atropine prevented the contractile response of the ileum.
Furthermore, interferon Îł increased the affinity of carbachol for
the cholinoceptors and did not change its maximum effect. Neurogenic
pathways were also involved since pretreatment of ileum with
hexamethonium, hemicholinium or tetrodotoxin impaired the
contractile effect of interferon Îł. In contrast to the action of
exogenous carbachol, the effects of interferon Îł are indirect. They
appear to involve a G protein regulating phosphoinositide turnover
and cytoskeletal structures since they could not be induced in ileum
strips that were pretreated with pertussis toxin, phospholipase C
inhibitors (2-nitro-carboxyphenyl, NN-diphenyl carbamate and
neomycin), cytochalasine B or colchicine
Homogeneous and Narrow Bandwidth of Spike Initiation in Rat L1 Cortical Interneurons
The cortical layer 1 (L1) contains a population of GABAergic interneurons, considered a key component of information integration, processing, and relaying in neocortical networks. In fact, L1 interneurons combine top\u2013down information with feed-forward sensory inputs in layer 2/3 and 5 pyramidal cells (PCs), while filtering their incoming signals. Despite the importance of L1 for network emerging phenomena, little is known on the dynamics of the spike initiation and the encoding properties of its neurons. Using acute brain tissue slices from the rat neocortex, combined with the analysis of an existing database of model neurons, we investigated the dynamical transfer properties of these cells by sampling an entire population of known \u201celectrical classes\u201d and comparing experiments and model predictions. We found the bandwidth of spike initiation to be significantly narrower than in L2/3 and 5 PCs, with values below 100 cycle/s, but without significant heterogeneity in the cell response properties across distinct electrical types. The upper limit of the neuronal bandwidth was significantly correlated to the mean firing rate, as anticipated from theoretical studies but not reported for PCs. At high spectral frequencies, the magnitude of the neuronal response attenuated as a power-law, with an exponent significantly smaller than what was reported for pyramidal neurons and reminiscent of the dynamics of a \u201cleaky\u201d integrate-and-fire model of spike initiation. Finally, most of our in vitro results matched quantitatively the numerical simulations of the models as a further contribution to independently validate the models against novel experimental data
A renormalization-group analysis of the interacting resonant level model at finite bias: Generic analytic study of static properties and quench dynamics
Using a real-time renormalization group method we study the minimal model of
a quantum dot dominated by charge fluctuations, the two-lead interacting
resonant level model, at finite bias voltage. We develop a set of RG equations
to treat the case of weak and strong charge fluctuations, together with the
determination of power-law exponents up to second order in the Coulomb
interaction. We derive analytic expressions for the charge susceptibility, the
steady-state current and the conductance in the situation of arbitrary system
parameters, in particular away from the particle-hole symmetric point and for
asymmetric Coulomb interactions. In the generic asymmetric situation we find
that power laws can be observed for the current only as function of the level
position (gate voltage) but not as function of the voltage. Furthermore, we
study the quench dynamics after a sudden switch-on of the level-lead couplings.
The time evolution of the dot occupation and current is governed by exponential
relaxation accompanied by voltage-dependent oscillations and characteristic
algebraic decay.Comment: 24 pages, 13 figures; revised versio
Assisted hopping and interaction effects in impurity models
We study, using Numerical Renormalization Group methods, the generalization
of the Anderson impurity model where the hopping depends on the filling of the
impurity. We show that the model, for sufficiently large values of the assisted
hopping term, shows a regime where local pairing correlations are enhanced.
These correlations involve pairs fluctuating between on site and nearest
neighbor positions
Kondo quantum dot coupled to ferromagnetic leads: Numerical renormalization group study
We systematically study the influence of ferromagnetic leads on the Kondo
resonance in a quantum dot tuned to the local moment regime. We employ Wilson's
numerical renormalization group method, extended to handle leads with a spin
asymmetric density of states, to identify the effects of (i) a finite spin
polarization in the leads (at the Fermi-surface), (ii) a Stoner splitting in
the bands (governed by the band edges) and (iii) an arbitrary shape of the
leads density of states. For a generic lead density of states the quantum dot
favors being occupied by a particular spin-species due to exchange interaction
with ferromagnetic leads leading to a suppression and splitting of the Kondo
resonance. The application of a magnetic field can compensate this asymmetry
restoring the Kondo effect. We study both the gate-voltage dependence (for a
fixed band structure in the leads) and the spin polarization dependence (for
fixed gate voltage) of this compensation field for various types of bands.
Interestingly, we find that the full recovery of the Kondo resonance of a
quantum dot in presence of leads with an energy dependent density of states is
not only possible by an appropriately tuned external magnetic field but also
via an appropriately tuned gate voltage. For flat bands simple formulas for the
splitting of the local level as a function of the spin polarization and gate
voltage are given.Comment: 18 pages, 18 figures, accepted for publication in PR
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The challenges of long-delayed prosecutions in fighting impunity in Bangladesh
This article focuses on the challenges of âlong-delayedâ prosecutions, that is, criminal prosecutions that begin decades after the conflict, using the experience of the International Criminal Tribunal for Bangladesh (ICT-BD) as a case study. This issue is still an insufficiently discussed topic even though such prosecutions are likely to become more common in the future. The focus of this article is mainly on the legal and broader, transitional justice challenges of long-delayed prosecutions at the ICT-BD. The article examines how such prosecutions have had a contradictory, twofold effect: on the one hand, they have partially broken the endemic culture of impunity that was allowed to prevail for decades in Bangladesh. On the other hand, however, they have been highly controversial and may have served to deepen alienation of the Islamist opposition in Bangladesh. The article concludes that the question of whether long-delayed prosecutions are desirable for a particular society remains highly context-dependent and, in some cases, mechanisms other than criminal trials may be better suited to dealing with the past
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âIf I Would Stay Alive, I Would Be Their Voiceâ: On the Legitimacy of International People's Tribunals
In recent years there has been a proliferation of People's Tribunals (PTs), promising to address atrocities that have fallen through the net of a statist international legal order. However, the status of such informal tribunals has remained controversial in both literature and practice. The dominant view has been that PTs simply lack legitimate authority. Positing that, in the language game of legitimacy, PTs are put on a perpetual argumentative backfoot, this article examines aspects of their input, process and output legitimacy. It is argued that the right of victims-survivors to be heard reigns supreme and it is in upholding that right that the authority of PTs is legitimised. In the current state of international justice, PTs constitute indispensable, quasi-judicial institutions that bridge gaps in access to justice, challenge official narratives (or silences) about atrocities and, potentially, open up new avenues towards justice and recognition
Analysing the distance decay of community similarity in river networks using Bayesian methods
The distance decay of community similarity (DDCS) is a pattern that is widely observed in terrestrial
and aquatic environments. Niche-based theories argue that species are sorted in space according
to their ability to adapt to new environmental conditions. The ecological neutral theory argues
that community similarity decays due to ecological drift. The continuum hypothesis provides an
intermediate perspective between niche-based theories and the neutral theory, arguing that niche
and neutral factors are at the opposite ends of a continuum that ranges from competitive to stochastic
exclusion. We assessed the association between niche-based and neutral factors and changes in
community similarity measured by Sorensenâs index in riparian plant communities. We assessed the
importance of neutral processes using network distances and flow connection and of niche-based
processes using Strahler order differences and precipitation differences. We used a hierarchical
Bayesian approach to determine which perspective is best supported by the results. We used dataset
composed of 338 vegetation censuses from eleven river basins in continental Portugal. We observed
that changes in Sorensen indices were associated with network distance, flow connection, Strahler
order difference and precipitation difference but to different degrees. The results suggest that
community similarity changes are associated with environmental and neutral factors, supporting the
continuum hypothesisinfo:eu-repo/semantics/publishedVersio
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