2,124 research outputs found
Non-equilibrium transport through a disordered molecular nanowire
We investigate the non-equilibrium transport properties of a disordered
molecular nanowire. The nanowire is regarded as a quasi-one-dimensional organic
crystal composed of self-assembled molecules. One orbital and a single random
energy are assigned to each molecule while the intermolecular coupling does not
fluctuate. Consequently, electronic states are expected to be spatially
localized. We consider the regime of strong localization, namely, the
localization length is smaller than the length of the molecular wire.
Electron-vibron interaction, taking place in each single molecule, is also
taken into account. We investigate the interplay between disorder and
electron-vibron interaction in response to either an applied electric bias or a
temperature gradient. To this end, we calculate the electric and heat currents
when the nanowire is connected to leads, using the Keldysh non-equilibrium
Green's function formalism. At intermediate temperature, scattering by disorder
dominates both charge and heat transport. We find that the electron-vibron
interaction enhances the effect of the disorder on the transport properties due
to the exponential suppression of tunneling
Differential algebraic equations of MOS circuits and jump behavior
Many nonlinear electronic circuits showing fast switching behavior exhibit jump effects which occurs when the state space of the electronic system contains a fold. This leads to difficulties during the simulation of these systems with standard circuit simulators. A method to overcome these problems is by regularization, where parasitic inductors and capacitors are added at the suitable locations. However, the transient solution will not be reliable if this regularization is not done in accordance with Tikhonov's Theorem. A geometric approach is taken to overcome these problems by explicitly computing the state space and jump points of the circuit. Until now, work has been done in analyzing example circuits exhibiting this behavior for BJT transistors. In this work we apply these methods to MOS circuits (Schmitt trigger, flip flop and multivibrator) and present the numerical results. To analyze the circuits we use the EKV drain current model as equivalent circuit model for the MOS transistors.DFGDAA
Beyond Win-Win in Cyberspace
Published in cooperation with the American Bar Association Section of Dispute Resolutio
Universality and its Origins at the Amorphous Solidification Transition
Systems undergoing an equilibrium phase transition from a liquid state to an
amorphous solid state exhibit certain universal characteristics. Chief among
these are the fraction of particles that are randomly localized and the scaling
functions that describe the order parameter and (equivalently) the statistical
distribution of localization lengths for these localized particles. The purpose
of this Paper is to discuss the origins and consequences of this universality,
and in doing so, three themes are explored. First, a replica-Landau-type
approach is formulated for the universality class of systems that are composed
of extended objects connected by permanent random constraints and undergo
amorphous solidification at a critical density of constraints. This formulation
generalizes the cases of randomly cross-linked and end-linked macromolecular
systems, discussed previously. The universal replica free energy is
constructed, in terms of the replica order parameter appropriate to amorphous
solidification, the value of the order parameter is obtained in the liquid and
amorphous solid states, and the chief universal characteristics are determined.
Second, the theory is reformulated in terms of the distribution of local static
density fluctuations rather than the replica order parameter. It is shown that
a suitable free energy can be constructed, depending on the distribution of
static density fluctuations, and that this formulation yields precisely the
same conclusions as the replica approach. Third, the universal predictions of
the theory are compared with the results of extensive numerical simulations of
randomly cross-linked macromolecular systems, due to Barsky and Plischke, and
excellent agreement is found.Comment: 10 pages, including 3 figures (REVTEX
Immunoadsorption of agonistic autoantibodies against α1-adrenergic receptors in patients with mild to moderate dementia
Dementia has been shown to be associated with agonistic autoantibodies. The deleterious action of autoantibodies on the {alpha}1-adrenergic receptor for brain vasculature has been demonstrated in animal studies. In the current study, 169 patients with dementia were screened for the presence of agonistic autoantibodies. 47% of patients suffering from mild to moderate Alzheimer's disease and/or vascular dementia carried these autoantibodies. Eight patients positive for autoantibodies underwent immunoadsorption. Patients treated on four consecutive days were subsequently negative for autoantibodies and displayed stabilization of cognitive and mental condition during 12-18 months' follow-up. In patients treated for 2-3 days, autoantibodies were reduced by only 78%. They suffered a rebound of autoantibodies during follow-up, benefited from immunoadsorption too, but their mental parameters worsened. We provide first data on the clinical relevance of agonistic autoantibodies in dementia and show that immunoadsorption is safe and efficient in removing autoantibodies with overall benefits for patients
Optimizing internet-delivered cognitive behaviour therapy for alcohol misuse—a randomized factorial trial examining effects of a pre-treatment assessment interview and guidance
Background: Internet-delivered cognitive behavioral therapy (ICBT) for alcohol misuse has potential to radically improve access to evidence-based care, and there is a need to investigate ways to optimize its delivery in clinical settings. Guidance from a clinician has previously been shown to improve drinking outcomes in ICBT, and some studies suggest that pre-treatment assessments may contribute in initiating early change. The objective of this study was to investigate the added and combined effects of a pre-treatment assessment interview and guidance on the outcomes of ICBT for alcohol misuse delivered in an online therapy clinic.
Methods: A 2X2 factorial randomized controlled trial was conducted where participants received access to an 8-week ICBT program, and either a pre-treatment assessment interview (Factor 1), guidance (Factor 2), a combination of these, or neither of these. Participants were 270 individuals (66.8% female, mean age = 46.5) scoring 8 or more on the Alcohol Use Disorders Identification Test and consuming 14 standard drinks or more in the preceding week. Primary outcomes were number of drinks consumed and number of heavy drinking days during the preceding week, 3 months post-treatment.
Results: Large within-group effects were found in terms of alcohol reductions (dw ≥ 0.82, p < 0.001), but neither of the factors significantly improved drinking outcomes. Guidance was associated with greater adherence (i.e. completed modules).
Conclusions: Neither a pre-treatment assessment interview nor guidance from a clinician appears to improve drinking outcomes resulting from internet-delivered cognitive behaviour therapy for alcohol misuse when delivered in a routine online therapy clinic.
Trial registration: NCT03984786. Registered 13 June 2019, https://clinicaltrials.gov/ct2/show/NCT03984786.
Keywords: Alcohol; Assessment reactivity; Cognitive behavior therapy; Guidance; Internet; Treatmen
Today’s older adults are cognitively fitter than older adults were 20 years ago, but when and how they decline is no different than in the past
History-graded increases in older adults' levels of cognitive performance are well documented, but little is known about historical shifts in within-person change: cognitive decline and onset of decline. We combined harmonized perceptual-motor speed data from independent samples recruited in 1990 and 2010 to obtain 2,008 age-matched longitudinal observations (M = 78 years, 50% women) from 228 participants in the Berlin Aging Study (BASE) and 583 participants in the Berlin Aging Study II (BASE-II). We used nonlinear growth models that orthogonalized within- and between-person age effects and controlled for retest effects. At age 78, the later-born BASE-II cohort substantially outperformed the earlier-born BASE cohort (d = 1.20; 25 years of age difference). Age trajectories, however, were parallel, and there was no evidence of cohort differences in the amount or rate of decline and the onset of decline. Cognitive functioning has shifted to higher levels, but cognitive decline in old age appears to proceed similarly as it did two decades ago
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