1,143 research outputs found

    On Spatial Consensus Formation: Is the Sznajd Model Different from a Voter Model?

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    In this paper, we investigate the so-called ``Sznajd Model'' (SM) in one dimension, which is a simple cellular automata approach to consensus formation among two opposite opinions (described by spin up or down). To elucidate the SM dynamics, we first provide results of computer simulations for the spatio-temporal evolution of the opinion distribution L(t)L(t), the evolution of magnetization m(t)m(t), the distribution of decision times P(τ)P(\tau) and relaxation times P(μ)P(\mu). In the main part of the paper, it is shown that the SM can be completely reformulated in terms of a linear VM, where the transition rates towards a given opinion are directly proportional to frequency of the respective opinion of the second-nearest neighbors (no matter what the nearest neighbors are). So, the SM dynamics can be reduced to one rule, ``Just follow your second-nearest neighbor''. The equivalence is demonstrated by extensive computer simulations that show the same behavior between SM and VM in terms of L(t)L(t), m(t)m(t), P(τ)P(\tau), P(μ)P(\mu), and the final attractor statistics. The reformulation of the SM in terms of a VM involves a new parameter σ\sigma, to bias between anti- and ferromagnetic decisions in the case of frustration. We show that σ\sigma plays a crucial role in explaining the phase transition observed in SM. We further explore the role of synchronous versus asynchronous update rules on the intermediate dynamics and the final attractors. Compared to the original SM, we find three additional attractors, two of them related to an asymmetric coexistence between the opposite opinions.Comment: 22 pages, 20 figures. For related publications see http://www.ais.fraunhofer.de/~fran

    Psychophysical Evaluation of a Sanshool Derivative (Alkylamide) and the Elucidation of Mechanisms Subserving Tingle

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    Previous studies investigated the neural and molecular underpinnings of the tingle sensation evoked by sanshool and other natural or synthetic alkylamides. Currently, we sought to characterize the psychophysical properties associated with administration of these compounds. Like other chemesthetic stimuli, the synthetic tingle analog isobutylalkylamide (IBA) evoked a sensation that was temporally dynamic. Repeated IBA application at short (30 sec) interstimulus intervals (ISI) resulted in a tingle sensation that increased across trials. Application at longer ISIs (∼30 min) resulted in a sensation of decreased intensity consistent with self-desensitization. Prior treatment with the TRPV1 or TRPA1 agonists, capsaicin and mustard oil did not cross-desensitize the tingle sensation evoked by IBA suggesting that neither TRPV1 nor TRPA1 participate in the transduction mechanism sub-serving tingle. When evaluated over 30-min time period, lingual IBA evoked a sensation that was described initially as tingling and pungent but after approximately 15 min, as a cooling sensation. Further, we found that the sensation evoked by lingual IBA was potentiated by simultaneous application of cold (0°C) and cool (21°C) thermal stimuli but was unaffected by warm (33°C) and hot (41°C) temperatures. Finally, to test the hypothesis that the tingling sensation is subserved by the activation of mechanosensitve fibers, we evaluated lingual tactile thresholds in the presence and absence of lingual IBA. The presence of IBA significantly raised lingual tactile thresholds, whereas capsaicin did not, identifying a role for mechanosensitive fibers in conveying the tingle sensation evoked by sanshool-like compounds. Collectively, these results show that lingual alkylamide evokes a complex sensation that is temporally dynamic and consistent with in vitro and in vivo experiments suggesting these compounds activate mechanosensitve neurons via blockade of KCNK two-pore potassium channels to induce the novel tingling sensation

    Electrical Conductivity Measurements on Gel Grown KDP Crystals Added with KCL and KNO3

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    SILVER NANOPARTICLES FROM TRIANTHEMA PORTULACASTRUM: GREEN SYNTHESIS, CHARACTERIZATION, ANTIBACTERIAL AND ANTICANCER PROPERTIES

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    ABSTRACTObjective: In this study, silver nanoparticles (SNPs) were synthesized using an aqueous extract of Trainthema portulacastrum and silver ions (Ag+)which have been proven against certain pathogenic bacterial strains and hepatocellular carcinoma (HepG2) cell line.Methods: The bio fabricated nanoparticles were confirmed by surface plasmon resonance which were characterized by biophysical measuresutilizing the ultraviolet-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray, and transmission electron microscope(TEM), Fourier transform infrared spectroscopy, particle size analyzer, and X-ray diffraction. Antibacterial efficacy against Enterobacter aerogens,Proteus mirabilis, Escherichia coli, Staphylococcus epidermis, and Bacillus subtilis. The effect of SNPs tested against HepG2 and NIH/3T3 cell lineexhibits a dose-dependent toxicity.Results and Conclusion: The SEM and TEM images confirmed the presence of spherical and hexagonal shape (0.3-4 μm) of nanocrystalline particleswith the size range of 11.5-29.2 nm. The average particles size of SNPs is 190.3±17.0 nm. Antibacterial activity was carried out by agar well diffusionmethod against different pathogenic bacteria of which B. subtilis showed a significant zone of inhibition 8.66 mm and 12.0 mm for aqueous plantextract and synthesized SNPs. The effect of SNPs tested against HepG2 and NIH/3T3 cell line exhibits a dose-dependent toxicity. In case of HepG2, thecell viability was decreased to 50% (IC50) at the concentration of 173.8±0.84 μg/mL. From the results, it can be concluded that the SNPs fabricatedusing green synthesis method will be a promising candidate in the biomedical field, due to its high bioactive properties.Keywords: Silver nanoparticles, Trainthema portulacastrum, Antibacterial activity, Cytotoxic activity

    A note on a gauge-gravity relation and functional determinants

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    We present a refinement of a recently found gauge-gravity relation between one-loop effective actions: on the gauge side, for a massive charged scalar in 2d dimensions in a constant maximally symmetric electromagnetic field; on the gravity side, for a massive spinor in d-dimensional (Euclidean) anti-de Sitter space. The inclusion of the dimensionally regularized volume of AdS leads to complete mapping within dimensional regularization. In even-dimensional AdS, we get a small correction to the original proposal; whereas in odd-dimensional AdS, the mapping is totally new and subtle, with the `holographic trace anomaly' playing a crucial role.Comment: 6 pages, io

    Shari T. Oral History

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    All oral histories in the Under the Rainbow: Oral Histories of Gay, Lesbian, Bisexual, Transgender, Intersex and Queer People in Kansas are copyrighted and protected by copyright law (Title 17, U. S. Code). Requests for permission to publish quotations beyond “fair use” from this collection should be addressed to: Tami Albin ([email protected] or [email protected] ) Director of Under the Rainbow: Oral Histories of GLBTIQ People in Kansas Anschutz Library 1301 Hoch Auditoria Dr. University of Kansas Lawrence, KS 66045 Requestors must identify: 1. Type of publication 2. Proposed title 3. Specific passages to be quoted, 4. Anticipated uses of the passages 5. Publisher’s name 6. Expected date of publication.This interview was made possible in part by the generous support of the University of Kansas Libraries and the University of Kansas grants 2302114, 2301283, 2301334

    Synthesis and Characterization of Chitosan Nanoaggregates from Gladius of Uroteuthis duvauceli

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    We report the synthesis, characterization, and biological properties of chitosan nanoaggregates from gladius of squid, Uroteuthis duvauceli. β-Chitin extracted from gladius was deacetylated to chitosan and further reduced to nanosize using ionic gelation process. The morphology and occurrence of chitosan nanoaggregates (CSNA) were observed using transmission electron microscopy (TEM). The degree of deacetylation (DD%) calculated from Fourier transform infrared (FTIR) spectrum showed high value (~94 ± 1.25%) for chitosan. The CSNA depicts low molecular weight, stable positive zeta potential, and less ash and moisture content with high water and fat binding capacity. The antimicrobial activity was tested against pathogenic microorganisms, which depicted significant rate of inhibition against Staphylococcus aureus and Escherichia coli due to high cellular uptake. The antioxidant analysis for CSNA demonstrated high reducing power and scavenging activity towards superoxide radicals compared with the commercially available chitosan. Furthermore, nanoaggregates exhibited low cytotoxic behavior in biological in vitro tests performed using cervical cancer cell line. These results indicate that chitosan nanoaggregates synthesized from waste gladius will be highly efficient and safe candidate for biological applications as food packing film, drug carrier, and tissue engineering

    Regional vesicular acetylcholine transporter distribution in human brain: A [18F]fluoroethoxybenzovesamicol positron emission tomography study

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    Prior efforts to image cholinergic projections in human brain in vivo had significant technical limitations. We used the vesicular acetylcholine transporter (VAChT) ligand [18F]fluoroethoxybenzovesamicol ([18F]FEOBV) and positron emission tomography to determine the regional distribution of VAChT binding sites in normal human brain. We studied 29 subjects (mean age 47 [range 20–81] years; 18 men; 11 women). [18F]FEOBV binding was highest in striatum, intermediate in the amygdala, hippocampal formation, thalamus, rostral brainstem, some cerebellar regions, and lower in other regions. Neocortical [18F]FEOBV binding was inhomogeneous with relatively high binding in insula, BA24, BA25, BA27, BA28, BA34, BA35, pericentral cortex, and lowest in BA17–19. Thalamic [18F]FEOBV binding was inhomogeneous with greatest binding in the lateral geniculate nuclei and relatively high binding in medial and posterior thalamus. Cerebellar cortical [18F]FEOBV binding was high in vermis and flocculus, and lower in the lateral cortices. Brainstem [18F]FEOBV binding was most prominent at the mesopontine junction, likely associated with the pedunculopontine–laterodorsal tegmental complex. Significant [18F]FEOBV binding was present throughout the brainstem. Some regions, including the striatum, primary sensorimotor cortex, and anterior cingulate cortex exhibited age‐related decreases in [18F]FEOBV binding. These results are consistent with prior studies of cholinergic projections in other species and prior postmortem human studies. There is a distinctive pattern of human neocortical VChAT expression. The patterns of thalamic and cerebellar cortical cholinergic terminal distribution are likely unique to humans. Normal aging is associated with regionally specific reductions in [18F]FEOBV binding in some cortical regions and the striatum.Using [18F]FEOBV PET, we describe the distribution of cholinergic terminals in human brain. The distribution of cholinergic terminals is similar to that found in other mammals with some distinctive features in cortex, thalamus, and cerebellum. There are regionally specific age‐related changes in cholinergic terminal density.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146604/1/cne24541.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146604/2/cne24541_am.pd

    Estimation of Sea Ice Thickness Distributions through the Combination of Snow Depth and Satellite Laser Altimetry Data

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    Combinations of sea ice freeboard and snow depth measurements from satellite data have the potential to provide a means to derive global sea ice thickness values. However, large differences in spatial coverage and resolution between the measurements lead to uncertainties when combining the data. High resolution airborne laser altimeter retrievals of snow-ice freeboard and passive microwave retrievals of snow depth taken in March 2006 provide insight into the spatial variability of these quantities as well as optimal methods for combining high resolution satellite altimeter measurements with low resolution snow depth data. The aircraft measurements show a relationship between freeboard and snow depth for thin ice allowing the development of a method for estimating sea ice thickness from satellite laser altimetry data at their full spatial resolution. This method is used to estimate snow and ice thicknesses for the Arctic basin through the combination of freeboard data from ICESat, snow depth data over first-year ice from AMSR-E, and snow depth over multiyear ice from climatological data. Due to the non-linear dependence of heat flux on ice thickness, the impact on heat flux calculations when maintaining the full resolution of the ICESat data for ice thickness estimates is explored for typical winter conditions. Calculations of the basin-wide mean heat flux and ice growth rate using snow and ice thickness values at the 70 m spatial resolution of ICESat are found to be approximately one-third higher than those calculated from 25 km mean ice thickness values
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