4,411 research outputs found

    Equilibration of High Molecular-Weight Polymer Melts: A Hierarchical Strategy

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    A strategy is developed for generating equilibrated high molecular-weight polymer melts described with microscopic detail by sequentially backmapping coarse-grained (CG) configurations. The microscopic test model is generic but retains features like hard excluded volume interactions and realistic melt densities. The microscopic representation is mapped onto a model of soft spheres with fluctuating size, where each sphere represents a microscopic subchain with NbN_{\rm b} monomers. By varying NbN_{\rm b} a hierarchy of CG representations at different resolutions is obtained. Within this hierarchy, CG configurations equilibrated with Monte Carlo at low resolution are sequentially fine-grained into CG melts described with higher resolution. A Molecular Dynamics scheme is employed to slowly introduce the microscopic details into the latter. All backmapping steps involve only local polymer relaxation thus the computational efficiency of the scheme is independent of molecular weight, being just proportional to system size. To demonstrate the robustness of the approach, microscopic configurations containing up to n=1000n=1000 chains with polymerization degrees N=2000N=2000 are generated and equilibration is confirmed by monitoring key structural and conformational properties. The extension to much longer chains or branched polymers is straightforward

    Current management of obsessive and phobic states

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    Obsessional states show an average point prevalence of 1%–3% and a lifetime prevalence of 2%–2.5%. Most treatment-seeking patients with obsessions continue to experience significant symptoms after 2 years of prospective follow-up. A significant burden of impairment, distress, and comorbidity characterize the course of the illness, leading to an increased need for a better understanding of the nature and management of this condition. This review aims to give a representation of the current pharmacological and psychotherapeutic strategies used in the treatment of obsessive-compulsive disorder. Antidepressants (clomipramine and selective serotonin reuptake inhibitors) are generally the first-line choice used to handle obsessional states, showing good response rates and long-term positive outcomes. About 40% of patients fail to respond to selective serotonin reuptake inhibitors. So far, additional pharmacological treatment strategies have been shown to be effective, ie, administration of high doses of selective serotonin reuptake inhibitors, as well as combinations of different drugs, such as dopamine antagonists, are considered efficacious and well tolerated strategies in terms of symptom remission and side effects. Psychotherapy also plays an important role in the management of obsessive-compulsive disorder, being effective for a wide range of symptoms, and many studies have assessed its long-term efficacy, especially when added to appropriate pharmacotherapy. In this paper, we also give a description of the clinical and psychological features likely to characterize patients refractory to treatment for this illness, with the aim of highlighting the need for greater attention to more patient-oriented management of the disease

    Blunted glucocorticoid and mineralocorticoid sensitivity to stress in people with diabetes.

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    Psychological stress may contribute to type 2 diabetes but mechanisms are still poorly understood. In this study, we examined whether stress responsiveness is associated with glucocorticoid and mineralocorticoid sensitivity in a controlled experimental comparison of people with type 2 diabetes and non-diabetic participants. Thirty-seven diabetes patients and 37 healthy controls underwent psychophysiological stress testing. Glucocorticoid (GR) and mineralocorticoid sensitivity (MR) sensitivity were measured by dexamethasone- and prednisolone-inhibition of lipopolysaccharide (LPS)-induced interleukin (IL) 6 levels, respectively. Blood pressure (BP) and heart rate were monitored continuously, and we periodically assessed salivary cortisol, plasma IL-6 and monocyte chemotactic protein (MCP-1). Following stress, both glucocorticoid and mineralocorticoid sensitivity decreased among healthy controls, but did not change in people with diabetes. There was a main effect of group on dexamethasone (F(1,74)=6.852, p=0.013) and prednisolone (F(1,74)=7.295, p=0.010) sensitivity following stress at 45 min after tasks. People with diabetes showed blunted stress responsivity in systolic BP, diastolic BP, heart rate, IL-6, MCP-1, and impaired post-stress recovery in heart rate. People with Diabetes had higher cortisol levels as measured by the total amount excreted over the day and increased glucocorticoid sensitivity at baseline. Our study suggests that impaired stress responsivity in type-2 diabetes is in part due to a lack of stress-induced changes in mineralocorticoid and glucocorticoid sensitivity

    The Average AMS fellow who died before Aug. 2022 lived 83.36 years, published 98.53 papers, and was cited 2473.23 times

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    Using data collected from the AMS websites, and the internet in general, we compute the weight-enumerator of the set of 145 AMS fellows who passed away before Aug. 2022, according to the statistics [Age, Number of Publications, Number of Citations]. Using Maple and elementary calculus, we deduced from it the numbers stated in the title, as well as much more detailed and fascinating statistical information. For example, while the correlation coefficient between the number of publications and number of citations is, not surprisingly, positive, it is far lower than one would expect, being a mere 0.5797 . The appendices contain the rankings according to longevity, number of publications, and number of citations.Comment: 23 pages. Accompanied by a Maple package obtainable from https://sites.math.rutgers.edu/~zeilberg/tokhniot/AMSrip.tx

    Analisa Pengaruh Corporate Social Responsibility Terhadap Brand Image Dan Customer Loyalty Di Pop! Hotels Indonesia

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    Penelitian ini dilakukan untuk menganalisa pengaruh CSR terhadap brand image dan customer loyalty pada Pop! Hotels di Indonesia. Penelitian ini menggunakan pendekatan kuantitatif kausal dengan bantuan penyebaran kuesioner yang dibagikan kepada 200 responden yang pernah menginap di Pop! Hotels di Indonesia. Hasil penelitian menunjukkan bahwa CSR berpengaruh positif dan signifikan terhadap brand image dan customer loyalty. Selain itu CSR juga berpengaruh secara tidak langsung terhadap customer loyalty dengan brand image sebagai variabel intervening. This research aimed to analyse the impact of CSR on brand image and customer loyalty. Survey was conducted to 200 respondents who have stayed at Pop! Hotels Indonesia. The result showed that CSR had a positive and significant impact on brand image and customer loyalty. Moreover, CSR also had an indirect impact on customer loyalty with brand image as the intervening variable

    The Walk-in Counselling Model of Service Delivery: Who Benefits Most?

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    The walk-in counselling (WIC) model of service delivery has been found to reduce psychological distress more quickly than a traditional model of service delivery involving a wait list. A question remains, however, as to the relative benefit of the WIC model for different client groups. The present study uses graphical inspection and multilevel modeling to conduct moderator analyses comparing two agencies, one with a WIC clinic and the other with a traditional wait list approach, and their relative impact on psychological distress. Key findings regarding the differential benefits for different types of presenting problems as well as clients at different stages of change are discussed. La recherche montre qu\u27un service de consultation sans rendez-vous réduit la détresse psychologique plus rapidement qu\u27un modèle traditionnel fonctionnant avec liste d\u27attente. Les bénéfices relatifs du modèle de consultation sans rendez-vous pour différentes clientèles demeurent cependant méconnus. Cette étude utilise l\u27inspection de graphiques et la modélisation multiniveau afin de mener une analyse de modération qui compare deux cliniques: sans rendez-vous ou suivant le modèle traditionnel avec liste d\u27attente. L\u27étude examine les impacts relatifs de ces modèles sur la détresse psychologique. Les principaux résultats portent sur les bénéfices différentiels selon les problématiques de santé mentale présentées et selon les stades de changement des usagers

    Validation Of A Cariogenic Biofilm Model To Evaluate The Effect Of Fluoride On Enamel And Root Dentine Demineralization

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    Due to gingival recession both enamel and root dentine are at risk of developing caries. Both tissues are exposed to a similar environment, however there is not a validated model to evaluate the effect of fluoride on these dental substrates simultaneously. Hence, this study aimed to validate a caries model to evaluate the effect of fluoride to prevent demineralization on enamel and root-dentine. Streptococcus mutans UA159 biofilms were formed on saliva-coated bovine enamel and root dentine slabs (n = 12 per group) mounted in the same well of culture plates. The biofilms were exposed 8x/day to 10% sucrose and treated 2x/day with fluoridated solutions containing 0, 150, 450, or 1,350 ppm F; thus, simulating the use of low to high fluoride concentration toothpastes. The pH values of the culture medium was monitored 2x/day as a biofilm acidogenicity indicator. After 96 h, biofilms were collected for fluoride concentration analysis. The percentage of surface hardness loss (% SHL) was calculated for slabs. The fluoride uptake by the enamel and dentine was also determined. The model showed a dose-response because the biofilm and fluoride uptake increased and % SHL decreased at increasing fluoride concentrations (p < 0.05). Fluoride in the biofilm formed on dentine and fluoride uptake by dentine were higher than those for enamel. With the same fluoride concentration treatment, the percentage of reduction of demineralization was lower for dentine than for enamel. In conclusion, the model was validated in terms of a dose-response effect of fluoride on enamel and root dentine. Furthermore, the findings support the clinical data, suggesting that higher fluoride concentrations are necessary to control caries of root dentine than of enamel.111Foundation of UNICAMP (FUNCAMP) [4252

    Principles of wide bandwidth acoustic detectors and the single-mass DUAL detector

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    We apply the standard theory of the elastic body to obtain a set of equations describing the behavior of an acoustic Gravitational Wave detector, fully taking into account the 3-dimensional properties of the mass, the readout and the signal. We show that the advantages given by a Dual detector made by two nested oscillators can also be obtained by monitoring two different acoustic modes of the same oscillator, thus easing the detector realization. We apply these concepts and by means of an optimization process we derive the main figures of such a single-mass Dual detector designed specifically for the frequency interval 2-5kHz. Finally we calculate the SQL sensitivity of this detector.Comment: 29 pages, 10 figure

    Abundance of arthropods as food for meadow bird chicks in response to short- and long-term soil wetting in Dutch dairy grasslands

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    BackgroundThroughout the world, intensive dairy farming has resulted in grasslands almost devoid of arthropods and birds. Meadow birds appear to be especially vulnerable during the chick-rearing period. So far, studies have focused mainly on describing population declines, but solutions to effectively stop these trends on the short-term are lacking. In this study at a single farm, we experimentally manipulated soil moisture through occasional irrigation, to mitigate against early season drainage and create favorable conditions for the emergence of above-ground arthropods during the meadow bird chick rearing phase.MethodsTo guarantee the presence of at least a sizeable arthropod community for the measurement of effects of wetting, we selected a farm with low intensity management. The land use and intensity of the study site and surroundings were categorized according to the national land use database and quantified using remote sensing imagery. From May 1 to June 18, 2017, we compared a control situation, with no water added, to two wetting treatments, a “short-term” (3 weeks) treatment based on wetting on warm days with a sprinkler system and a “long-term” treatment next to a water pond with a consistently raised water table from 2010. We measured soil temperature, soil moisture and resistance as well as the biomass of arthropods at 3-day intervals. Flying arthropods were sampled by sticky traps and crawling arthropods by pitfall traps. Individual arthropods were identified to Order and their length recorded, to assess their relevance to meadow bird chicks.ResultsThe land use analysis confirmed that the selected dairy farm had very low intensity management. This was different from most of the surrounding area (20 km radius), characterized by (very) high intensity land use. The experiments showed that irrigation contributed to cooler soils during midday, and that his happened already in the early part of the season; the differences with the control increased with time. In the short- and long-term treatments, soil moisture increased and soil resistance decreased from the mid-measurement period onward. Compared with the control, cumulative arthropod biomass was higher in the long-term treatment, but showed no change in the irrigation treatment. We conclude that small-scale interventions, such as occasional irrigation, favorably affected local soil properties. However, the effects on above-ground arthropod abundance currently appear limited or overridden by negative landscape-scale processes on arthropods

    Melnikov theory to all orders and Puiseux series for subharmonic solutions

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    We study the problem of subharmonic bifurcations for analytic systems in the plane with perturbations depending periodically on time, in the case in which we only assume that the subharmonic Melnikov function has at least one zero. If the order of zero is odd, then there is always at least one subharmonic solution, whereas if the order is even in general other conditions have to be assumed to guarantee the existence of subharmonic solutions. Even when such solutions exist, in general they are not analytic in the perturbation parameter. We show that they are analytic in a fractional power of the perturbation parameter. To obtain a fully constructive algorithm which allows us not only to prove existence but also to obtain bounds on the radius of analyticity and to approximate the solutions within any fixed accuracy, we need further assumptions. The method we use to construct the solution -- when this is possible -- is based on a combination of the Newton-Puiseux algorithm and the tree formalism. This leads to a graphical representation of the solution in terms of diagrams. Finally, if the subharmonic Melnikov function is identically zero, we show that it is possible to introduce higher order generalisations, for which the same kind of analysis can be carried out.Comment: 30 pages, 6 figure
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