Percentile Queries in Multi-Dimensional Markov Decision Processes

Markov decision processes (MDPs) with multi-dimensional weights are useful to analyze systems with multiple objectives that may be conflicting and require the analysis of trade-offs. We study the complexity of percentile queries in such MDPs and give algorithms to synthesize strategies that enforce such constraints. Given a multi-dimensional weighted MDP and a quantitative payoff function $f$, thresholds $v_i$ (one per dimension), and probability thresholds $\alpha_i$, we show how to compute a single strategy to enforce that for all dimensions $i$, the probability of outcomes $\rho$ satisfying $f_i(\rho) \geq v_i$ is at least $\alpha_i$. We consider classical quantitative payoffs from the literature (sup, inf, lim sup, lim inf, mean-payoff, truncated sum, discounted sum). Our work extends to the quantitative case the multi-objective model checking problem studied by Etessami et al. in unweighted MDPs.Comment: Extended version of CAV 2015 pape

Investigation of the AODV and the SDWCA QoS handling at different utilisation levels in adaptive clustering environments

A simulation study using NS2 simulator using two main routing protocols with specific design parameters has been carried out to investigate the QoS main parameters such as throughput, delay, Jitter, Control Overhead, Number of packets, number of packets dropped and the rating overheads. The traffic is made of CBR slow video traffic. From the result it is noted that the SDWCA routing protocol outperforms the AODV routing protocols in the throughput, the delay and the jitter issues at different loading levels

Developing a framework for arts in health programs targeting individuals with chronic pain: a mixed-methods study of practitioners

Objectives: Chronic pain is a leading cause of morbidity and disability across the world. Cultural engagement may be a valuable tool in addressing the social disconnection that often accompanies chronic pain. This study sought to develop a framework for arts in health programs targeting individuals with chronic pain. / Study design: Sequential explanatory mixed-methods study. / Methods: Web-based, cross-sectional survey sent to arts and cultural professionals to assess their experience with arts in health programming. Semi-structured interviews conducted with a sample of survey respondents to explore their perspectives on targeted arts in health programming for individuals with chronic pain. / Results: Between October 2019 and January 2020, 208 surveys were completed by arts and cultural professionals. One hundred and twenty (58%) of the respondents indicated that they currently run an arts in health or museums in health program. Among these 120 respondents, 52 (43%) targeted older adults, 50 (42%) targeted individuals with mental health concerns, and 18 (15%) targeted individuals living with pain. Improving well-being (101 [84%]) and reducing social isolation (90 [75%]) were the most common intended program outcomes, while improving pain was the least common outcome (26 [22%]). Fifteen survey respondents were interviewed. Interviewees identified four interdependent themes regarding best practices for arts in health programs pertaining to (1) program content and structure, (2) program facilitation, (3) partnerships, and (4) programs for individuals with chronic pain. / Conclusions: The cultural sector can support chronic pain prevention and treatment efforts through the development of specialized programs. This study provides a framework for developing arts in health programs that support individuals living with chronic pain

Testing gene-environment interactions in gene-based association studies

Gene-based and single-nucleotide polymorphism (SNP) set association studies provide an important complement to SNP analysis. Kernel-based nonparametric regression has recently emerged as a powerful and flexible tool for this purpose. Our goal is to explore whether this approach can be extended to incorporate and test for interaction effects, especially for genes containing rare variant SNPs. Here, we construct nonparametric regression models that can be used to include a gene-environment interaction effect under the framework of the least-squares kernel machine and examine the performance of the proposed method on the Genetic Analysis Workshop 17 unrelated individuals data set. Two hundred simulated replicates were used to explore the power for detecting interaction. We demonstrate through a genome scan of the quantitative phenotype Q1 that the simulated gene-environment interaction effect in the data can be detected with reasonable power by using the least-squares kernel machine method

Mean-field cooperativity in chemical kinetics

We consider cooperative reactions and we study the effects of the interaction strength among the system components on the reaction rate, hence realizing a connection between microscopic and macroscopic observables. Our approach is based on statistical mechanics models and it is developed analytically via mean-field techniques. First of all, we show that, when the coupling strength is set positive, the model is able to consistently recover all the various cooperative measures previously introduced, hence obtaining a single unifying framework. Furthermore, we introduce a criterion to discriminate between weak and strong cooperativity, based on a measure of "susceptibility". We also properly extend the model in order to account for multiple attachments phenomena: this is realized by incorporating within the model $p$-body interactions, whose non-trivial cooperative capability is investigated too.Comment: 25 pages, 4 figure

An Optical Counterpart to the Anomalous X-ray Pulsar 4U 0142+61

The energy source of the anomalous X-ray pulsars is not well understood, hence their designation as anomalous. Unlike binary X-ray pulsars, no companions are seen, so the energy cannot be supplied by accretion of matter from a companion star. The loss of rotational energy, which powers radio pulsars, is insufficient to power AXPs. Two models are generally considered: accretion from a large disk left over from the birth process, or decay of a very strong magnetic field (10^15 G) associated with a 'magnetar'. The lack of counterparts at other wavelengths has hampered progress in our understanding of these objects. Here, we present deep optical observations of the field around 4U 0142+61, which is the brightest AXP in X-rays. We find an object with peculiar optical colours at the position of the X-ray source, and argue that it is the optical counterpart. The optical emission is too faint to admit the presence of a large accretion disk, but may be consistent with magnetospheric emission from a magnetar.Comment: 16 pages, 3 figures, accepted by Nature. Press embargo until 1900 hrs London time (GMT) on 6 December 200

Evolution of cooperation driven by zealots

Recent experimental results with humans involved in social dilemma games suggest that cooperation may be a contagious phenomenon and that the selection pressure operating on evolutionary dynamics (i.e., mimicry) is relatively weak. I propose an evolutionary dynamics model that links these experimental findings and evolution of cooperation. By assuming a small fraction of (imperfect) zealous cooperators, I show that a large fraction of cooperation emerges in evolutionary dynamics of social dilemma games. Even if defection is more lucrative than cooperation for most individuals, they often mimic cooperation of fellows unless the selection pressure is very strong. Then, zealous cooperators can transform the population to be even fully cooperative under standard evolutionary dynamics.Comment: 5 figure

Infratentorial superficial siderosis: Classification, diagnostic criteria and rational investigation pathway

Central nervous system infratentorial superficial siderosis (iSS) is increasingly detected by blood-sensitive MRI sequences. Despite this, there are no standardized diagnostic criteria, and the clinical-radiological spectrum, causes and optimum investigation strategy are not established. We reviewed clinical and radiological details of patients with iSS assessed at a specialist neurological center from 2004-2016 using pre-defined standardized radiological criteria. All imaging findings were rated blinded to clinical details. We identified 65 patients with iSS, which we classified into two groups: type 1 (classical) and type 2 (secondary) iSS. Type 1 (classical) iSS included 48 patients without any potentially causal radiologically-confirmed spontaneous or traumatic intracranial hemorrhage, of whom 39 (83%) had hearing loss, ataxia or myelopathy; type 2 (secondary) iSS included 17 patients with a potentially causal radiologically-confirmed spontaneous or traumatic intracranial hemorrhage, of whom none had hearing loss, ataxia or myelopathy. Of the patients with type 1 (classical) iSS, 40 (83%) had a potentially causal cranial or spinal dural abnormality; 5 (11%) had an alternative cause; and 3 (6%) had no cause identified. Intra-arterial digital subtraction angiography did not identify any underlying causal lesions for type 1 iSS. Type 1 (classical) iSS, defined using simple radiological criteria, is associated with a characteristic neurological syndrome. Rational investigation, including spinal MRI, nearly always reveals a potential cause, most often a dural abnormality. Catheter angiography appears to be unhelpful, suggesting that classical iSS is not associated with macrovascular arterial pathology. Recognition of type 1 (classical) iSS should allow timely diagnosis and early consideration of treatment

On reminder effects, drop-outs and dominance: evidence from an online experiment on charitable giving

We present the results of an experiment that (a) shows the usefulness of screening out drop-outs and (b) tests whether different methods of payment and reminder intervals affect charitable giving. Following a lab session, participants could make online donations to charity for a total duration of three months. Our procedure justifying the exclusion of drop-outs consists in requiring participants to collect payments in person flexibly and as known in advance and as highlighted to them later. Our interpretation is that participants who failed to collect their positive payments under these circumstances are likely not to satisfy dominance. If we restrict the sample to subjects who did not drop out, but not otherwise, reminders significantly increase the overall amount of charitable giving. We also find that weekly reminders are no more effective than monthly reminders in increasing charitable giving, and that, in our three months duration experiment, standing orders do not increase giving relative to one-off donations

Betel nut and tobacco chewing; potential risk factors of cancer of oesophagus in Assam, India

Cancer of the oesophagus is the most commonly diagnosed cancer in males in Assam, in north-eastern India, and ranks second for females. The chewing of betel nut, with or without tobacco and prepared in various ways, is a common practice in the region and a case–control study has been designed to study the pattern of risk associated with different ways of preparing and chewing the nuts. 358 newly diagnosed male patients and 144 female have been interviewed together with 2 control subjects for each case chosen at random from among the attendants who accompanied patients to hospital. There were significant trends in risk ratios associated with the frequency of chewing each day, with the duration of chewing in years and with the age at which the habit was started that were apparent for both males and females and which remained significant after allowance was made for other known risk factors, notably tobacco smoking and alcohol consumption. The adjusted ratios, in comparison with non-chewers, were 13.3 M and 5.7 F for chewing more than 20 times a day, 10.6 M and 7.2 F for persons who had chewed for more than 20 years and 10.3 M and 5.3 F for those who had started before the age of 20. Among the different combinations of ingredients that were chewed the adjusted odds ratios were highest for those who had been using fermented betel nut with any form of tobacco (7.1 M and 3.6 F). The risk associated with tobacco smoking and alcohol consumption, which are high in some parts of the world, were less in Assam than those associated with the chewing of betel nut. © 2001 Cancer Research Campaign http://www.bjcancer.co