Power laws of natural swarms as fingerprints of an extended critical region.

Collective biological systems display power laws for macroscopic quantities and are fertile probing grounds for statistical physics. Besides power laws, natural insect swarms present strong scale-free correlations, suggesting closeness to phase transitions. Swarms exhibit imperfect dynamic scaling: their dynamical correlation functions collapse into single curves when written as functions of the scaled time tξ^{-z} (ξ: correlation length, z: dynamic exponent), but only for short times. Triggered by markers, natural swarms are not invariant under space translations. Measured static and dynamic critical exponents differ from those of equilibrium and many nonequilibrium phase transitions. Here we show the following: (i) The recently discovered scale-free-chaos phase transition of the harmonically confined Vicsek model has a novel extended critical region for N (finite) insects that contains several critical lines. (ii) As alignment noise vanishes, there are power laws connecting critical confinement and noise that allow calculating static critical exponents for fixed N. These power laws imply that the unmeasurable confinement strength is proportional to the perception range measured in natural swarms. (iii) Observations of natural swarms occur at different times and under different atmospheric conditions, which we mimic by considering mixtures of data on different critical lines and N. Unlike results of other theoretical approaches, our numerical simulations reproduce the previously described features of natural swarms and yield static and dynamic critical exponents that agree with observations.

Mean-field theory of chaotic insect swarms.

The harmonically confined Vicsek model displays qualitative and quantitative features observed in natural insect swarms. It exhibits a scale-free transition between single and multicluster chaotic phases. Finite-size scaling indicates that this unusual phase transition occurs at zero confinement [Phys. Rev. E 107, 014209 (2023)2470-004510.1103/PhysRevE.107.014209]. While the evidence of the scale-free-chaos phase transition comes from numerical simulations, here we present its mean-field theory. Analytically determined critical exponents are those of the Landau theory of equilibrium phase transitions plus dynamical critical exponent z=1 and a new critical exponent φ=0.5 for the largest Lyapunov exponent. The phase transition occurs at zero confinement and noise in the mean-field theory. The noise line of zero largest Lyapunov exponents informs observed behavior: (i) the qualitative shape of the swarm (on average, the center of mass rotates slowly at the rate marked by the winding number and its trajectory fills compactly the space, similarly to the observed condensed nucleus surrounded by vapor) and (ii) the critical exponents resemble those observed in natural swarms. Our predictions include power laws for the frequency of the maximal spectral amplitude and the winding number.

Scale-free chaos in the confined Vicsek flocking model.

The Vicsek model encompasses the paradigm of active dry matter. Motivated by collective behavior of insects in swarms, we have studied finite-size effects and criticality in the three-dimensional, harmonically confined Vicsek model. We have discovered a phase transition that exists for appropriate noise and small confinement strength. On the critical line of confinement versus noise, swarms are in a state of scale-free chaos characterized by minimal correlation time, correlation length proportional to swarm size and topological data analysis. The critical line separates dispersed single clusters from confined multicluster swarms. Scale-free chaotic swarms occupy a compact region of space and comprise a recognizable "condensed" nucleus and particles leaving and entering it. Susceptibility, correlation length, dynamic correlation function, and largest Lyapunov exponent obey power laws. The critical line and a narrow criticality region close to it move simultaneously to zero confinement strength for infinitely many particles. At the end of the first chaotic window of confinement, there is another phase transition to infinitely dense clusters of finite size that may be termed flocking black holes.

Consumption of seafood and its estimated heavy metals are associated with lipid profile and oxidative lipid damage on healthy adults from a Spanish Mediterranean area: A cross-sectional study.

The association between the consumption of seafood and its benefits on cardiovascular (CVD) risk can be challenged by its heavy metal (HM) content. This study aimed to explore the association of seafood consumption and its estimated HM contents with the lipid profile and lipid oxidation biomarkers in adults from a Spanish Mediterranean area who do not present risk factors for CVD. In this cross-sectional study, the clinical history, three-day dietary record, lipid profile (LDLc, HDLc, APOB/A, and triglyceride levels), plasma oxidised LDL (oxLDL) and 8-isoprostane levels of 81 adults without risk factors for CVD [43% men, with a mean age of 43.6 years (95%CI: 40.1-47.1)] were assessed. The HM [arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb)] contents of seafood were estimated according to data from analyses of marine species in the same Mediterranean area. Moderate adherence to the Mediterranean diet (score: 4.6 of 9) with a mean seafood consumption of 74.9g/day (95%CI: 59.9-89.9), including 22.7g of shellfish per day (95%CI: 13.5-31.9), was observed. The estimated HM contents were lower than the provisional tolerable weekly intakes (PTWIs): 21.12µg/kg/week As, 0.57µg/kg/week InAs, 0.15µg/kg/week Cd, 1.11µg/kg/week Hg and 0.28µg/kg/week Pb. After adjusting by confounder variables, an increase in shellfish consumption was associated with increases in the levels of LDLc (P=0.013), non-HDLc (P=0.015), APOB/A (P=0.02) and plasma oxLDL (P=0.002). Moreover, an increase in the estimated As and Hg levels in shellfish was associated with an increase in LDLc (P=0.015 and P=0.018, respectively), non-HDLc (P<0.008 and P<0.008, respectively), APOB/A ratio (P=0.008 and P=0.009, respectively), and oxLDL (P≤0.001 and P≤0.001, respectively) levels. In conclusion, in adults without risk factors for CVD, increasing shellfish consumption, even by a moderate amount, could favour a pro-atherogenic lipid profile and a higher level of oxidised LDL. These associations are likely influenced by the estimated exposure to As and Hg from shellfish despite these values are lower than the PTWIs.

Pharmaceutical consumption and cost in patients with dementia: A longitudinal study by the Registry of Dementias of Girona (ReDeGi) in Catalonia (Spain).

OBJECTIVE: Drug spending increases exponentially from the age of 65-70 years, and dementia is one of the diseases significantly contributing to this increase. Our aim was to describe pharmaceutical consumption and cost in patients with dementia, using the Anatomical Therapeutic Chemical (ATC) classification system. We also assessed the evolution of costs and consumption, and the variables associated to this evolution during three years. METHODS: Three years prospective cohort study using data from the ReDeGi and the Health Region of Girona (HRG) Pharmacy Unit database from the Public Catalan Healthcare Service (PCHS). Frequency of consumption and costs of ATC categories of drugs were calculated. RESULTS: Sample of 869 patients with dementia, most of them with a diagnosis of degenerative dementia (72.6%), and in a mild stage of the disease (68.2%). Central nervous system (CNS) drugs had the highest consumption rate (97.2%), followed by metabolic system drugs (80.1%), and cardiovascular system drugs (75.4%). Total pharmaceutical cost was of 2124.8 € per patient/year (standard deviation (SD)=1018.5 €), and spending on CNS drugs was 55.5% of the total cost. After 36 months, pharmaceutical cost increased in 694.9 € (SD=1741.9), which was associated with dementia severity and institutionalization at baseline. CONCLUSIONS: Pharmaceutical consumption and costs are high in patients with dementia, and they increase with time, showing an association with baseline dementia severity and institutionalization. CNS drugs are the pharmaceuticals with highest prescription rates and associated costs.

Genetic variation and structure in the Mediterranean shrubs Myrtus communis and Pistacia lentiscus in different landscape contexts.

Studies concerning different habitat configurations can provide insights into the complex interactions between species' life-history traits and the environment and can help to predict patterns in population genetics. In this study, we compared patterns of genetic variation in two Mediterranean shrub species (Myrtus communis and Pistacia lentiscus) that co-occur in populations within three contrasting landscape contexts: continuous, fragmented-connected and fragmented-isolated populations. Analysing variation at microsatellites loci, our results revealed weak responses to the landscape contexts. We rather found a population-specific response in both study species. However, despite both study species sharing similar levels of genetic diversity, Myrtus displayed higher levels of homozygosity and genetic differentiation among populations, stronger patterns of within-population spatial genetic structure, lower values of mutation-scaled effective population size and stronger evidence for recent genetic bottlenecks than Pistacia. This result highlights the influence of past events (e.g. historical connectivity, fluctuations in population size) and local factors (e.g. microhabitat availability for recruitment, habitat quality, plant density, native fauna) and that the landscape configuration per se (i.e. fragment size and/or isolation) might not completely determine the species' genetic patterns.

Permanent genetic resources added to molecular ecology resources database 1 April 2013-31 May 2013.

This article documents the addition of 234 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Acipenser sinensis, Aleochara bilineata, Aleochara bipustulata, Barbus meridionalis, Colossoma macropomum, Delia radicum, Drosophila nigrosparsa, Fontainea picrosperma, Helianthemum cinereum, Liomys pictus, Megabalanus azoricus, Pelteobagrus vachelli, Pleuragramma antarcticum, Podarcis hispanica type 1A, Sardinella brasiliensis and Sclerotinia homoeocarpa. These loci were cross-tested on the following species: Acipenser dabryanus, Barbus balcanicus, Barbus barbus, Barbus cyclolepis, Drosophila hydei, Drosophila melanogaster, Drosophila obscura, Drosophila subobscura, Fontainea australis, Fontainea fugax, Fontainea oraria, Fontainea rostrata, Fontainea venosa, Podarcis bocagei, Podarcis carbonelli, Podarcis liolepis, Podarcis muralis and Podarcis vaucheri.

[Patient associated fire in theatre: are we ready to prevent and/or manage it? Assessment of the anaesthetist's knowledge in Lorraine]. / Feu d'un patient au bloc opératoire: sommes-nous prêts à gérer ce type d'incident ? Résultats d'une enquête faite auprès des médecins anesthésistes-réanimateurs lorrains.

OBJECTIVE: To assess knowledge amongst anaesthetists as regards to fire involving surgical patients in Lorraine. STUDY DESIGN: A cross-sectional study was conducted using a postal questionnaire. METHOD: A 22-item postal questionnaire was therefore sent to all anaesthetists working in Lorraine between January and March, 2011. RESULTS: One hundred and twenty-eight questionnaires were returned (response rate: 36%). Sixty-two percent of the respondents had never participated in fire safety training. Fifty percent could not recollect the location of the fire extinguisher in their surgical unit. Sixty-three percent ignored the existence of a memo written by the Afssaps summarizing how to use safely alcohol-based skin preparations in the presence of an electrosurgical unit. Sixty-five percent gave at least one incorrect response in grading the various modes of oxygen supply regarding the risk of fire. Only 48% were able to identify the surgeries which posed the greatest fire risk. In such cases, 40% of respondents were not aware that a FiO(2) should be maintained below 30%, 43% that the use of nitrous oxide was forbidden and 32% that it was necessary to respect a drying time after the application of an alcohol-based solution. Concerning the management of a fire, most of the answers were correct. Finally, 97% of the respondents wished to be better informed on this particular topic. CONCLUSION: Our survey underlines a lack of knowledge amongst anaesthetists towards the risk of patient associated fire in theatre.

Population genetic structure in Myrtus communis L. in a chronically fragmented landscape in the Mediterranean: can gene flow counteract habitat perturbation?

Ancient managed landscapes provide ideal opportunities to assess the consequences of habitat fragmentation on the patterns of genetic diversity and gene flow in long-lived plant species. Using amplified fragment length polymorphism (AFLP) and allozyme markers, we quantified seed-mediated gene flow and population genetic diversity and structure in 14 populations of Myrtus communis (myrtle), a common endozoochorous shrub species of forest patches in lowland agricultural Mediterranean areas. Overall, allozyme diversity for myrtle was low (P(95) = 25%; A = 1.411; H(e) = 0.085) compared to other known populations, and a significant portion of populations (57%) had lower levels of allelic diversity and/or heterozygosity than expected at random, as shown by simulated resampling of the whole diversity of the landscape. We found significant correlations between allozyme variability and population size and patch isolation, but no significant inbreeding in any population. Genetic differentiation among populations for both allozyme and AFLP markers was significant (Phi(ST) = 0.144 and Phi(ST) = 0.142, respectively) but an isolation-by-distance pattern was not detected. Assignment tests on AFLP data indicated a high immigration rate in the populations (ca. 20-22%), likely through effective seed dispersal across the landscape by birds and mammals. Our results suggest that genetic isolation is not the automatic outcome of habitat destruction since substantial levels of seed-mediated gene flow are currently detectable. However, even moderate rates of gene flow seem insufficient in this long-lived species to counteract the genetic erosion and differentiation imposed by chronic habitat destruction.

[Burnout syndrome epidemiology]. / Epidemiología del síndrome de burnout.

The burnout syndrome constitutes a process which bears high prevalence and important consequences among sanitary professionals, particularly among nurses. Therefore, the authors have proposed to study the three dimensions of this syndrome, namely emotional tiredness, depersonalization and lack of a sense of achievement plus the function certain personal, labor, and institutional factors have in development of this process. The authors carried out a transversal study based on a random sample from among all the nursing staff at a Madrid hospital. Two methods to gather information were employed: one questionnaire gathered sociodemographic data, labor and institutional variables while the Maslach Burnout Inventory (MBI), in its verified Spanish version, studied the three burnout syndrome dimensions. The authors made a multiple logistical regression analysis, using as dependent variables the three syndrome scales and adjusting parameters for all the other variables. Clear risk factors were shown; these included unfavorable opinions professionals hold regarding institutional variables; the scale for emotional tiredness warrants special note.

Mutagenicidad en aguas de consumo mediante el test de reversión trp- en Escherichia coli / Mutagenicity in drinking water

Una de las principales fuentes de mutágenos ambientales se deriva de la cloración de las aguas de consumo público, ya que es bien conocido que el cloro reacciona con precursores del agua produciendo un grupo de compuestos que incluyen posibles carcinógenos humanos. Con el objeto de evaluar la actividad mutagénica de derivados orgánicos procedentes del agua de consumo de Madrid, nos planteamos utilizar el test de mutación reversa con Escherichia coli. Material y métodos: Se emplearon las cepas de Escherichia coli triptófano dependientes, WP2, WP2 uvrA – y WP2 uvrA – pKM 101. Cada experiencia se realizó con y sin activación metabólica (mezcla S9) y utilizando el método de incorporación en placa. Las muestras de agua fueron procesadas con el fin de concentrar los compuestos orgánicos clorados. Resultados y conclusiones: No hemos encontrado actividad mutagénica positiva con ninguna de las cepas de ensayo. Los mayores índices de mutación se obtuvieron con la cepa WP2 uvrA – pKM 101 y en las experiencias sin fracción microsomal (índice de mutación de 1,84) (AU)

Chlorinated drinking water is one of the primary sources of enviromental mutagens. Chlorine reacts with specific water precursors, creating a group of compounds with suspected human carcinogens. This study was conducted to investigate possible mutagenic activity in organic chlorinated compounds in the drinking water in Madrid using the Escherichia coli everse mutation assay. Materials and methods: Escherichia coli triptophan-dependent strains WP2, WP2 uvrA – and WP2 uvrA – pKM 101 were used in this study. Each test was performed with and without metabolic activation (S9 mix), using the plate incorporation method. The water samples were processed in order to concentrate the organic chlorinated compounds. Results and conclusions: No positive activity was found in any of the strains tested. The highest levels of mutagenicity appeared in the WP2 uvrA – pKM 101 strain and in the test where the microsome fraction was not used (index of mutation, 1.84) (AU)

Geriatría y urgencias hospitalarias / Geriatrics and hospital emergencies

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Adherence of mouse peritoneal macrophages following exposure to lead.

Lead is a toxin widely used in industry. Recently, medical investigation into lead exposure has turned to testing organ systems, such as the immune system, that historically were not associated with lead poisoning. We evaluated the effects of doses of 13, 130 or 1,300 ppm of lead on the adherence of mouse peritoneal cells, and particularly on macrophages. Cellular adherence was measured according to the De la Fuente technique. Adherence of macrophages showed significant changes in the 1,300 ppm group, revealing a reduction to 55% of the control group. The macrophage adherence index showed 91% sensitivity and 96% specificity. These results indicate a considerable reduction in the adherence of peritoneal macrophages following exposure to certain levels of lead.