1,039 research outputs found

    Critical Infrastructures You Can Trust: Where Telecommunications Fits

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    This paper discusses two NISs: the public telephone network (PTN) and the Internet. Being themselves large and complex NISs, they not only merit study in their own right but can help us to understand some of the technical problems faced by the developers and operators of other NISs. In addition, the high cost of building a global communications infrastructure from the ground up implies that one or both of these two networks is likely to furnish communications services for most other NISs. Therefore, an understanding of the vulnerabilties of the PTN and Internet informs the assessment of the trustworthiness of other NISs. Ideas for improving the trustworthiness of the PTN and Internet are also proposed, both for the short-term (by improved use of existing technologies and procedures) and for the long-term (by identifying some areas where the state-of-the-art is inadequate and research is therefore needed). Finally, some observations are offered about Internet telephony and the use of the Internet for critical infrastructures

    Imaging dielectric relaxation in nanostructured polymers by frequency modulation electrostatic force microscopy

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    We have developed a method for imaging the temperature-frequency dependence of the dynamics of nanostructured polymer films with spatial resolution. This method provides images with dielectric compositional contrast well decoupled from topography. Using frequency-modulation electrostatic-force-microscopy, we probe the local frequency-dependent (0.1–100 Hz) dielectric response through measurement of the amplitude and phase of the force gradient in response to an oscillating applied electric field. When the phase is imaged at fixed frequency, it reveals the spatial variation in dielectric losses, i.e., the spatial variation in molecular/dipolar dynamics, with 40 nm lateral resolution. This is demonstrated by using as a model system; a phase separated polystyrene/polyvinyl-acetate (PVAc) blend. We show that nanoscale dynamic domains of PVAc are clearly identifiable in phase images as those which light-up in a band of temperature, reflecting the variations in the molecular/dipolar dynamics approaching the glass transition temperature of PVAc

    Aggregated dynamic demand equations for specialistic-outpatient medical care:(Estimated from a time-series of cross-sections)

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    In this paper a dynamic model is presented which describes the development of the demand for specialistic medical care in The Netherlands, during the period 1960-1972. The "regionally correlated, time-wise auto-regressive" model is consistently estimated from a time-series of cross-sections, using a modified Aitken estimator. The dependent variables are the number of publicly insured patients referred from general care to specialistic care, and the amount of care consumed per patient referred. As independent variables we took demographic factors, the supply of different levels of medical care and the insurance system. The estimation results show a.o. important substitution possibilities between general and specialistic care, and a significant influence of supply and supply-related variables on the demand for specialistic care.</p

    Data concatenation, Bayesian concordance and coalescent-based analyses of the species tree for the rapid radiation of Triturus newts

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    The phylogenetic relationships for rapid species radiations are difficult to disentangle. Here we study one such case, namely the genus Triturus, which is composed of the marbled and crested newts. We analyze data for 38 genetic markers, positioned in 3-prime untranslated regions of protein-coding genes, obtained with 454 sequencing. Our dataset includes twenty Triturus newts and represents all nine species. Bayesian analysis of population structure allocates all individuals to their respective species. The branching patterns obtained by data concatenation, Bayesian concordance analysis and coalescent-based estimations of the species tree differ from one another. The data concatenation based species tree shows high branch support but branching order is considerably affected by allele choice in the case of heterozygotes in the concatenation process. Bayesian concordance analysis expresses the conflict between individual gene trees for part of the Triturus species tree as low concordance factors. The coalescent-based species tree is relatively similar to a previously published species tree based upon morphology and full mtDNA and any conflicting internal branches are not highly supported. Our findings reflect high gene tree discordance due to incomplete lineage sorting (possibly aggravated by hybridization) in combination with low information content of the markers employed (as can be expected for relatively recent species radiations). This case study highlights the complexity of resolving rapid radiations and we acknowledge that to convincingly resolve the Triturus species tree even more genes will have to be consulted

    Health–economic Benefits of Treating Trauma in Psychosis

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    Background: Co-occurrence of posttraumatic stress disorder (PTSD) in psychosis (estimated as 12%) raises personal suffering and societal costs. Health–economic studies on PTSD treatments in patients with a diagnosis of a psychotic disorder have not yet been conducted, but are needed for guideline development and implementation. This study aims to analyse the cost-effectiveness of guideline PTSD therapies in patients with a psychotic disorder. Methods: This health–economic evaluation alongside a randomized controlled trial included 155 patients with a psychotic disorder in care as usual (CAU), with comorbid PTSD. Participants received eye movement desensitization and reprocessing (EMDR) (n = 55), prolonged exposure (PE) (n = 53) or waiting list (WL) (n = 47) with masked assessments at baseline (T0) and at the two-month (post-treatment, T2) and six-month follow-up (T6). Costs were calculated using the TiC-P interview for assessing healthcare consumption and productivity losses. Incremental cost-effectiveness ratios and economic acceptability were calculated for quality-adjusted life years (EQ-5D-3L-based QALYs) and PTSD ‘Loss of diagnosis’ (LoD, CAPS). Results: Compared to WL, costs were lower in EMDR (-€1410) and PE (-€501) per patient per six months. In addition, EMDR (robust SE 0.024, t = 2.14, p = .035) and PE (robust SE 0.024, t = 2.14, p = .035) yielded a 0.052 and 0.051 incremental QALY gain, respectively, as well as 26% greater probability for LoD following EMDR (robust SE = 0.096, z = 2.66, p = .008) and 22% following PE (robust SE 0.098, z = 2.28, p = .023). Acceptability curves indicate high probabilities of PTSD treatments being the better economic choice. Sensitivity analyses corroborated these outcomes. Conclusion: Adding PTSD treatment to CAU for individuals with psychosis and PTSD seem to yield better health and less PTSD at lower costs, which argues for implementation

    Medical and surgical treatment for medication-induced tremor: case report and systematic review

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    Objective To present a case of refractory medication-induced tremor successfully treated with deep brain stimulation (DBS) of the thalamic ventral intermediate nucleus (Vim) and to propose a medical and surgical treatment algorithm based on a systematical review of the literature. Methods Patient data were retrospectively collected. A systematic search was performed in PubMed, Embase, and Cochrane Library. Subjective and objective data were pooled for analysis by classifying them into 5 predefined categories(no, minimal, moderate, good, and excellent effects). Results The patient presented with lithium-induced bilateral progressive hand tremor lasting 25 years. After DBS, he reported excellent tremor suppression until the last follow-up (36 months after Vim-DBS). For the review, 34 of 140 studies were included and evaluated (178 unique subjects, 31 different treatments). A good-to-excellent tremor suppression (50%-100%) in at least 50% of subjects was achieved using propranolol (12 studies, 50% of 56 subjects), tetrabenazine (5 studies, 51% of 13 subjects), and metoprolol (4 studies, 75% of 8 subjects). The effect of benztropine and diphenhydramine was none or only minimal to moderate (up to 50% improvement; both: 3 studies, 50% of 4 patients). One article reported minimal-to-moderate effectiveness after DBS of the ventral oral posterior nucleus of the thalamus. Methods were highly heterogeneous. All studies scored grade III or IV quality of evidence, which was insufficient for recommendations (level U). Conclusion Treatment decision making should be performed on a case-by-case basis considering the low level of evidence, and we propose a practically oriented treatment algorithm. Propranolol, tetrabenazine, and metoprolol might be effective. For selected and refractory cases, DBS might be considered.Neurological Motor Disorder
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