Quarantine generated phase transition in epidemic spreading

We study the critical effect of quarantine on the propagation of epidemics on an adaptive network of social contacts. For this purpose, we analyze the susceptible-infected-recovered (SIR) model in the presence of quarantine, where susceptible individuals protect themselves by disconnecting their links to infected neighbors with probability w, and reconnecting them to other susceptible individuals chosen at random. Starting from a single infected individual, we show by an analytical approach and simulations that there is a phase transition at a critical rewiring (quarantine) threshold w_c separating a phase (w<w_c) where the disease reaches a large fraction of the population, from a phase (w >= w_c) where the disease does not spread out. We find that in our model the topology of the network strongly affects the size of the propagation, and that w_c increases with the mean degree and heterogeneity of the network. We also find that w_c is reduced if we perform a preferential rewiring, in which the rewiring probability is proportional to the degree of infected nodes.Comment: 13 pages, 6 figure

Numerical evaluation of the upper critical dimension of percolation in scale-free networks

We propose a numerical method to evaluate the upper critical dimension $d_c$ of random percolation clusters in Erd\H{o}s-R\'{e}nyi networks and in scale-free networks with degree distribution ${\cal P}(k) \sim k^{-\lambda}$, where $k$ is the degree of a node and $\lambda$ is the broadness of the degree distribution. Our results report the theoretical prediction, $d_c = 2(\lambda - 1)/(\lambda - 3)$ for scale-free networks with $3 < \lambda < 4$ and $d_c = 6$ for Erd\H{o}s-R\'{e}nyi networks and scale-free networks with $\lambda > 4$. When the removal of nodes is not random but targeted on removing the highest degree nodes we obtain $d_c = 6$ for all $\lambda > 2$. Our method also yields a better numerical evaluation of the critical percolation threshold, $p_c$, for scale-free networks. Our results suggest that the finite size effects increases when $\lambda$ approaches 3 from above.Comment: 10 pages, 5 figure

The effect of exposure to radiofrequency fields on cancer risk in the general and working population: a protocol for a systematic review of human observational studies

BACKGROUND: The World Health Organization (WHO) has an ongoing project to assess potential health effects of exposure to radiofrequency electromagnetic fields (RF-EMF) in the general and working population. Here we present the protocol for a systematic review of the scientific literature on cancer hazards from exposure to RF-EMF in humans, commissioned by the WHO as part of that project. OBJECTIVE: To assess the quality and strength of the evidence provided by human observational studies for a causal association between exposure to RF-EMF and risk of neoplastic diseases. ELIGIBILITY CRITERIA: We will include cohort and case-control studies investigating neoplasia risks in relation to three types of exposure to RF-EMF: near-field, head-localized, exposure from wireless phone use (SR-A); far-field, whole body, environmental exposure from fixed-site transmitters (SR-B); near/far-field occupational exposures from use of handheld transceivers or RF-emitting equipment in the workplace (SR-C). While no restriction on tumour type will be applied, we will focus on selected neoplasms of the central nervous system (brain, meninges, pituitary gland, acoustic nerve) and salivary gland tumours (SR-A); brain tumours and leukaemias (SR-B, SR-C). INFORMATION SOURCES: Eligible studies will be identified through Medline, Embase, and EMF-Portal. RISK-OF-BIAS ASSESSMENT: We will use a tailored version of the OHAT's tool to evaluate the study's internal validity. DATA SYNTHESIS: We will consider separately studies on different tumours, neoplasm-specific risks from different exposure sources, and a given exposure-outcome pair in adults and children. When a quantitative synthesis of findings can be envisaged, the main aims of the meta-analysis will be to assess the strength of association and the shape of the exposure-response relationship; to quantify the degree of heterogeneity across studies; and explore the sources of inconsistency (if any). When a meta-analysis is judged inappropriate, we will perform a narrative synthesis, complemented by a structured tabulation of results and appropriate visual displays. EVIDENCE ASSESSMENT: Confidence in evidence will be assessed in line with the GRADE approach. FUNDING: This project is supported by the World Health Organization. Co-financing was provided by the New Zealand Ministry of Health; the Istituto Superiore di Sanita in its capacity as a WHO Collaborating Centre for Radiation and Health; ARPANSA as a WHO Collaborating Centre for Radiation Protection. REGISTRATION: PROSPERO CRD42021236798

Coevolution of Glauber-like Ising dynamics on typical networks

We consider coevolution of site status and link structures from two different initial networks: a one dimensional Ising chain and a scale free network. The dynamics is governed by a preassigned stability parameter $S$, and a rewiring factor $\phi$, that determines whether the Ising spin at the chosen site flips or whether the node gets rewired to another node in the system. This dynamics has also been studied with Ising spins distributed randomly among nodes which lie on a network with preferential attachment. We have observed the steady state average stability and magnetisation for both kinds of systems to have an idea about the effect of initial network topology. Although the average stability shows almost similar behaviour, the magnetisation depends on the initial condition we start from. Apart from the local dynamics, the global effect on the dynamics has also been studied. These parameters show interesting variations for different values of $S$ and $\phi$, which helps in determining the steady-state condition for a given substrate.Comment: 8 pages, 10 figure

Epidemics in partially overlapped multiplex networks

Many real networks exhibit a layered structure in which links in each layer reflect the function of nodes on different environments. These multiple types of links are usually represented by a multiplex network in which each layer has a different topology. In real-world networks, however, not all nodes are present on every layer. To generate a more realistic scenario, we use a generalized multiplex network and assume that only a fraction $q$ of the nodes are shared by the layers. We develop a theoretical framework for a branching process to describe the spread of an epidemic on these partially overlapped multiplex networks. This allows us to obtain the fraction of infected individuals as a function of the effective probability that the disease will be transmitted $T$. We also theoretically determine the dependence of the epidemic threshold on the fraction $q > 0$ of shared nodes in a system composed of two layers. We find that in the limit of $q \to 0$ the threshold is dominated by the layer with the smaller isolated threshold. Although a system of two completely isolated networks is nearly indistinguishable from a system of two networks that share just a few nodes, we find that the presence of these few shared nodes causes the epidemic threshold of the isolated network with the lower propagating capacity to change discontinuously and to acquire the threshold of the other network.Comment: 13 pages, 4 figure

Art therapy, arts-based research and transitional stories of domestic violence and abuse

Visual imagery within qualitative research is an established method of gathering data that has parallels to the way in which images are used within art therapy. This paper explores how visual imagery was used to investigate women’s responses to domestic violence and abuse and examines how art therapy principles shaped the development and conducting of that research. Through the use of collage, participants created visual representations of their responses to experiences of domestic violence and abuse. The visual representations were, when combined with spoken words, created stories that reference the past, present and future. The stories created have been termed transitional stories of domestic violence. These stories show that the home has special significance for women as they transition away from domestic violence and plan for their future. The home becomes both a metaphorical and physical manifestation and container of hopes for a harmonious future that often incorporates the desire for the return to the idea of a complete family. This paper will present the findings of the arts-based research conducted, and consider the implications upon art therapy practice of those findings.N

Surface Photochemistry: 3,3′-Dialkylthia and Selenocarbocyanine Dyes Adsorbed onto Microcrystalline Cellulose

In this work, thia and selenocarbocyanines with n-alkyl chains of different length, namely with methyl, ethyl, propyl, hexyl and decyl substituents, were studied in homogeneous and heterogeneous media for comparison purposes. For both carbocyanine dyes adsorbed onto microcrystalline cellulose, a remarkable increase in the fluorescence quantum yields and lifetimes were detected, when compared with solution. Contrary to the solution behaviour, where the increase in the n-alkyl chains length increases to a certain extent the fluorescence emission ΦF and τF, on powdered solid samples a decrease of ΦF and τF was observed. The use of an integrating sphere enabled us to obtain absolute ΦF’s for all the powdered samples. The main difference for liquid homogeneous samples is that the increase of the alkyl chain strongly decreases the ΦF values, both for thiacarbocyanines and selenocarbocyanines. A lifetime distribution analysis for the fluorescence of these dyes adsorbed onto microcrystalline cellulose, evidenced location on the ordered and crystalline part of the substrate, as well as on the more disordered region where the lifetime is smaller. The increase of the n-alkyl chains length decreases the photoisomer emission for the dyes adsorbed onto microcrystalline cellulose, as detected for high fluences of the laser excitation, for most samples

Religious pro-sociality? Experimental evidence from a sample of 766 Spaniards

This study explores the relationship between several personal religion-related variables and social behaviour, using three paradigmatic economic games: the dictator (DG), ultimatum (UG), and trust (TG) games. A large carefully designed sample of the urban adult population in Granada (Spain) is employed (N = 766). From participants' decisions in these games we obtain measures of altruism, bargaining behaviour and sense of fairness/equality, trust, and positive reciprocity. Three dimensions of religiosity are examined: (i) religious denomination; (ii) intensity of religiosity, measured by active participation at church services; and (iii) conversion out into a different denomination than the one raised in. The major results are: (i) individuals with “no religion” made decisions closer to rational selfish behaviour in the DG and the UG compared to those who affiliate with a “standard” religious denomination; (ii) among Catholics, intensity of religiosity is the key variable that affects social behaviour insofar as religiously-active individuals are generally more pro-social than non-active ones; and (iii) the religion raised in seems to have no effect on pro-sociality, beyond the effect of the current measures of religiosity. Importantly, behaviour in the TG is not predicted by any of the religion-related variables we analyse. While the results partially support the notion of religious pro-sociality, on the other hand, they also highlight the importance of closely examining the multidimensional nature of both religiosity and pro-social behaviour

Is there adaptation in the ozone mortality relationship: A multi-city case-crossover analysis

<p>Abstract</p> <p>Background</p> <p>Ozone has been associated with daily mortality, mainly in the summer period. Despite the ample literature on adaptation of inflammatory and pulmonary responses to ozone, and the link, in cohort studies, between lung function and mortality risk there has been little done to date to examine the question of adaptation in the acute mortality risk associated with ambient ozone.</p> <p>Methods</p> <p>We applied a case-crossover design in 48 US cities to examine the ozone effect by season, by month and by age groups, particularly focusing on whether there was an adaptation effect.</p> <p>Results</p> <p>We found that the same day ozone effect was highest in summer with a 0.5% (95% CI: 0.38, 0.62) increase in total mortality for 10 ppb increase in 8-hr ozone, whilst the effect decrease to null in autumn and winter. We found higher effects in the months May- July with a 0.46% (95% CI: 0.24, 0.68) increase in total mortality for 10 ppb increase in ozone in June, and a 0.65% (95% CI: 0.47, 0.82) increase in mortality during July. The effect decreased in August and became null in September. We found similar effects from the age group 51–60 up to age 80 and a lower effect in 80 years and older.</p> <p>Conclusion</p> <p>The mortality effects of ozone appear diminished later in the ozone season, reaching the null effect previously reported in winter by September. More work should address this issue and examine the biological mechanism of adaptation.</p

Feasibility of a cohort study on health risks caused by occupational exposure to radiofrequency electromagnetic fields

Breckenkamp J, Berg-Beckhoff G, Muenster E, et al. Feasibility of a cohort study on health risks caused by occupational exposure to radiofrequency electromagnetic fields. Environmental Health. 2009;8(1):23.Background: The aim of this study was to examine the feasibility of performing a cohort study on health risks from occupational exposure to radiofrequency electromagnetic fields (RF-EMF) in Germany. Methods: A set of criteria was developed to evaluate the feasibility of such a cohort study. The criteria aimed at conditions of exposure and exposure assessment (level, duration, preferably on an individual basis), the possibility to assemble a cohort and the feasibility of ascertaining various disease endpoints. Results: Twenty occupational settings with workers potentially exposed to RF-EMF and, in addition, a cohort of amateur radio operators were considered. Based on expert ratings, literature reviews and our set of predefined criteria, three of the cohorts were identified as promising for further evaluation: the personnel (technicians) of medium/short wave broadcasting stations, amateur radio operators, and workers on dielectric heat sealers. After further analyses, the cohort of workers on dielectric heat sealers seems not to be feasible due to the small number of exposed workers available and to the difficulty of assessing exposure (exposure depends heavily on the respective working process and mixture of exposures, e.g. plastic vapours), although exposure was highest in this occupational setting. The advantage of the cohort of amateur radio operators was the large number of persons it includes, while the advantage of the cohort of personnel working at broadcasting stations was the quality of retrospective exposure assessment. However, in the cohort of amateur radio operators the exposure assessment was limited, and the cohort of technicians was hampered by the small number of persons working in this profession. Conclusion: The majority of occupational groups exposed to RF-EMF are not practicable for setting up an occupational cohort study due to the small numbers of exposed subjects or due to exposure levels being only marginally higher than those of the general public