Absence of epidemic threshold in scale free networks with degree correlations

Random scale-free networks have the peculiar property of being prone to the spreading of infections. Here we provide for the susceptible-infected-susceptible model an exact result showing that a scale-free degree distribution with diverging second moment is a sufficient condition to have null epidemic threshold in unstructured networks with either assortative or disassortative mixing. Degree correlations result therefore irrelevant for the epidemic spreading picture in these scale-free networks. The present result is related to the divergence of the average nearest neighbors degree, enforced by the degree detailed balance condition.

Detection of new cross-reacting carcinoembryonic antigen(s) on cultured tumor cells by mixed hemadsorption assay.

Antisera highly specific for carcinoembryonic antigen (CEA) from New Zealand White rabbits and a goat reacted strongly in antibody binding tests with cultured tumor cell lines, irrespective of the ability of the cell lines to produce CEA. The most reactive were colon carcinoma and melanoma cell lines, the former known to produce CEA and the latter not associated with CEA production. The reactivity was not diminished by absorption with perchloric acid extracts of normal lung or spleen, whereas absoprtion with purified CEA preparations abolished the reactivity. Quantitative absorption studies indicated that reactivity against CEA-producing cell lines could be totally removed by absorption with other CEA-producing lines but not with melanoma cell lines. Reactivity against melanoma cell lines could be completely removed by colon carcinoma cells as well as by melanoma cells. Antisera raised against purified CEA, after absorption with extracts of normal lung, still contained two populations of antibodies, one that binds a newly described antigen cross-reacting with CEA which is present on melanoma cells.

SPATIAL CORRELATION BETWEEN PHYSICAL PROPERTIES OF SOIL AND WEEDS IN TWO MANAGEMENT SYSTEMS

The spatial correlation between soil properties and weeds is relevant in agronomic and environmental terms. The analysis of this correlation is crucial for the interpretation of its meaning, for influencing factors such as dispersal mechanisms, seed production and survival, and the range of influence of soil management techniques. This study aimed to evaluate the spatial correlation between the physical properties of soil and weeds in no-tillage (NT) and conventional tillage (CT) systems. The following physical properties of soil and weeds were analyzed: soil bulk density, macroporosity, microporosity, total porosity, aeration capacity of soil matrix, soil water content at field capacity, weed shoot biomass, weed density, Commelina benghalensis density, and Bidens pilosa density. Generally, the ranges of the spatial correlations were higher in NT than in CT. The cross-variograms showed that many variables have a structure of combined spatial variation and can therefore be mapped from one another by co-kriging. This combined variation also allows inferences about the physical and biological meanings of the study variables. Results also showed that soil management systems influence the spatial dependence structure significantly.

Long-range correlations in diffusive systems away from equilibrium

We study the dynamics of density fluctuations in purely diffusive systems away from equilibrium. Under some conditions the static density correlation function becomes long ranged. We then analyze this behavior in the framework of nonequilibrium fluctuating hydrodynamics.

Correlations in weighted networks

We develop a statistical theory to characterize correlations in weighted networks. We define the appropriate metrics quantifying correlations and show that strictly uncorrelated weighted networks do not exist due to the presence of structural constraints. We also introduce an algorithm for generating maximally random weighted networks with arbitrary P(k,s) to be used as null models. The application of our measures to real networks reveals the importance of weights in a correct understanding and modeling of these heterogeneous systems.

The contributions of sensory dominance and attentional bias to cross-modal enhancement of visual cortex excitability.

Approaching or looming sounds (L-sounds) have been shown to selectively increase visual cortex excitability [Romei, V., Murray, M. M., Cappe, C., & Thut, G. Preperceptual and stimulus-selective enhancement of low-level human visual cortex excitability by sounds. Current Biology, 19, 1799-1805, 2009]. These cross-modal effects start at an early, preperceptual stage of sound processing and persist with increasing sound duration. Here, we identified individual factors contributing to cross-modal effects on visual cortex excitability and studied the persistence of effects after sound offset. To this end, we probed the impact of different L-sound velocities on phosphene perception postsound as a function of individual auditory versus visual preference/dominance using single-pulse TMS over the occipital pole. We found that the boosting of phosphene perception by L-sounds continued for several tens of milliseconds after the end of the L-sound and was temporally sensitive to different L-sound profiles (velocities). In addition, we found that this depended on an individual's preferred sensory modality (auditory vs. visual) as determined through a divided attention task (attentional preference), but not on their simple threshold detection level per sensory modality. Whereas individuals with "visual preference" showed enhanced phosphene perception irrespective of L-sound velocity, those with "auditory preference" showed differential peaks in phosphene perception whose delays after sound-offset followed the different L-sound velocity profiles. These novel findings suggest that looming signals modulate visual cortex excitability beyond sound duration possibly to support prompt identification and reaction to potentially dangerous approaching objects. The observed interindividual differences favor the idea that unlike early effects this late L-sound impact on visual cortex excitability is influenced by cross-modal attentional mechanisms rather than low-level sensory processes.

Affective state and voice : cross-cultural assessment of speaking behavior and voice sound characteristics : a normative multicenter study of 577 + 36 healthy subjects

BACKGROUND: Human speech is greatly influenced by the speakers' affective state, such as sadness, happiness, grief, guilt, fear, anger, aggression, faintheartedness, shame, sexual arousal, love, amongst others. Attentive listeners discover a lot about the affective state of their dialog partners with no great effort, and without having to talk about it explicitly during a conversation or on the phone. On the other hand, speech dysfunctions, such as slow, delayed or monotonous speech, are prominent features of affective disorders. METHODS: This project was comprised of four studies with healthy volunteers from Bristol (English: n = 117), Lausanne (French: n = 128), Zurich (German: n = 208), and Valencia (Spanish: n = 124). All samples were stratified according to gender, age, and education. The specific study design with different types of spoken text along with repeated assessments at 14-day intervals allowed us to estimate the 'natural' variation of speech parameters over time, and to analyze the sensitivity of speech parameters with respect to form and content of spoken text. Additionally, our project included a longitudinal self-assessment study with university students from Zurich (n = 18) and unemployed adults from Valencia (n = 18) in order to test the feasibility of the speech analysis method in home environments. RESULTS: The normative data showed that speaking behavior and voice sound characteristics can be quantified in a reproducible and language-independent way. The high resolution of the method was verified by a computerized assignment of speech parameter patterns to languages at a success rate of 90%, while the correct assignment to texts was 70%. In the longitudinal self-assessment study we calculated individual 'baselines' for each test person along with deviations thereof. The significance of such deviations was assessed through the normative reference data. CONCLUSIONS: Our data provided gender-, age-, and language-specific thresholds that allow one to reliably distinguish between 'natural fluctuations' and 'significant changes'. The longitudinal self-assessment study with repeated assessments at 1-day intervals over 14 days demonstrated the feasibility and efficiency of the speech analysis method in home environments, thus clearing the way to a broader range of applications in psychiatry. © 2014 S. Karger AG, Basel.

Upper gastrointestinal bleeding in cirrhosis: clinical and endoscopic correlations

The clinical data of 180 episodes of upper gastrointestinal bleeding in 168 patients with cirrhosis of the liver are examined. The source of bleeding had been determined by early endoscopy in all cases. In men under the age of 50 years, and without symptoms of liver failure, bleeding was due to ruptured gastro-oesophageal varices in 84% of cases. Severe liver failure was associated with acute lesions of gastric mucosa in many cases. No presumptive diagnosis of the source of haemorrhage could be based on the examination of other clinical data (presence of ascites, mode of presentation and pattern of bleeding, history of ulcer disease, alcoholism, and previous medication.

Medication use in pregnancy: a cross-sectional, multinational web-based study.

OBJECTIVES: Intercountry comparability between studies on medication use in pregnancy is difficult due to dissimilarities in study design and methodology. This study aimed to examine patterns and factors associated with medications use in pregnancy from a multinational perspective, with emphasis on type of medication utilised and indication for use. DESIGN: Cross-sectional, web-based study performed within the period from 1 October 2011 to 29 February 2012. Uniform collection of drug utilisation data was performed via an anonymous online questionnaire. SETTING: Multinational study in Europe (Western, Northern and Eastern), North and South America and Australia. PARTICIPANTS: Pregnant women and new mothers with children less than 1 year of age. PRIMARY AND SECONDARY OUTCOME MEASURES: Prevalence of and factors associated with medication use for acute/short-term illnesses, chronic/long-term disorders and over-the-counter (OTC) medication use. RESULTS: The study population included 9459 women, of which 81.2% reported use of at least one medication (prescribed or OTC) during pregnancy. Overall, OTC medication use occurred in 66.9% of the pregnancies, whereas 68.4% and 17% of women reported use of at least one medication for treatment of acute/short-term illnesses and chronic/long-term disorders, respectively. The extent of self-reported medicated illnesses and types of medication used by indication varied across regions, especially in relation to urinary tract infections, depression or OTC nasal sprays. Women with higher age or lower educational level, housewives or women with an unplanned pregnancy were those most often reporting use of medication for chronic/long-term disorders. Immigrant women in Western (adjusted OR (aOR): 0.55, 95% CI 0.34 to 0.87) and Northern Europe (aOR: 0.50, 95% CI 0.31 to 0.83) were less likely to report use of medication for chronic/long-term disorders during pregnancy than non-immigrants. CONCLUSIONS: In this study, the majority of women in Europe, North America, South America and Australia used at least one medication during pregnancy. There was a substantial inter-region variability in the types of medication used.

Upper gastrointestinal bleeding in cirrhosis: clinical and endoscopic correlations

The clinical data of 180 episodes of upper gastrointestinal bleeding in 168 patients with cirrhosis of the liver are examined. The source of bleeding had been determined by early endoscopy in all cases. In men under the age of 50 years, and without symptoms of liver failure, bleeding was due to ruptured gastro-oesophageal varices in 84% of cases. Severe liver failure was associated with acute lesions of gastric mucosa in many cases. No presumptive diagnosis of the source of haemorrhage could be based on the examination of other clinical data (presence of ascites, mode of presentation and pattern of bleeding, history of ulcer disease, alcoholism, and previous medication.

Mechanisms involved in the maintenance of inbreeding depression in gynodioecious "Silene vulgaris" (Caryophyllaceae): an experimental investigation

Summary Gynodioecy, the joint occurrence of females and hermaphrodites within natural populations, is a widely studied mating system ever since Darwin (1877). It is an exceptional mating system because continuous selection is necessary to maintain it. Since females only reproduce through ovules whereas hermaphrodites transmit genes through ovules and pollen, larger female fitness, in terms of seed output, is required to allow their maintenance. Two non-exclusive mechanisms can account for the maintenance of females. First, as females do not produce pollen they can reallocate their resources towards a higher ovule production. Second, hermaphrodites can self- and cross-fertilize whereas females are obligate outcrossers. Thus hermaphrodites should partly suffer from inbreeding depression (i.e.: the fitness decline of inbred relative to outbred individuals) and thereby produce less fit progeny than females. This thesis investigated the effects of self- and cross-fertilization of heimaphrodites over two consecutive generations. Inbreeding depression increased across the successive stages of the life- cycle (i.e.: from "seed traits" to "reproductive traits") displaying large inbreeding depression estimates (up to 0.76). This investigation not only detected large inbreeding depression estimates but also detected mechanisms involved in the maintenance of inbreeding depression. For instance cryptic self-incompatibility which is here a larger in vivo pollen performance of distant pollen compared to self-pollen; the expression of inbreeding depression especially in late life-cycle stages, and the appearance of females in the progeny of selfed hermaphrodites. The female biased sex ratio in the progeny of selfed hermaphrodites was a surprising result and could either come from the sex determining mechanisms (complex nucleo-cytoplasmic interaction(s)) and/or from inbreeding depression. Indeed, we not only got females and hermaphrodites but also partial male-sterile (PMS) individuals (i.e.: individuals with differing number of viable stamens). We detected that inbred pollen bearing plants (excluding females) have less viable stamens per flower than outbred plants. A positive correlation was detected between inbreeding depression for the number of viable stamens per flower and the difference in sex ratio between inbred and outbred individuals. A positive relationship was also detected between inbreeding depression for pollen viability and inbreeding depression for number of viable stamens per flower. Each correlation can either account for pleiotropic effects (a major gene acting on the two considered traits) or linkage disequilibrium between genes controlling each of the two related traits. If we hypothesize that these correlations are due to a major gene with pleiotropic effects, the positive relationship between inbreeding depression for number of viable stamens per flower and inbreeding depression for pollen viability showed that deleterious alleles present on a major gene coding for pollen production and viability depressed male fitness within inbred plants. The positive relationship between sex ratio difference between inbred and outbred individuals and inbreeding depression for number of viable stamens per flower indicates that (1) either number of viable stamens per flower is, in addition to inbreeding, also affected by the loci coding for sex determinism or, (2) the presence of females within the progeny of selfed hermaphrodites is a consequence of large inbreeding depression inhibiting pollen production, or (3) sex is here determined by a combination of loci coding for sex expression and inbreeding depression for male reproductive traits. In conclusion, Silene vulgaris has been shown to be a good model for understanding the evolution of mating systems that promote outbreeding. Résumé La gynodïoécie est définie comme étant la présence simultanée d'hermaphrodites et de femelles au sein de populations naturelles d'une même espèce. Ce système de reproduction a toujours fasciné le monde scientifique depuis Darwin, comme en témoigne ses écrits (1876, 1877) sur les systèmes de reproduction chez les plantes. Les femelles ne transmettent leurs gènes qu'à travers leurs ovules alors que les hermaphrodites transmettent leurs gènes à la fois par la voie mâle (le pollen) et la voie femelle (les ovules). La condition pour que la gynodïoécie se maintienne nécessite donc une fitness de la fonction femelle plus élevée chez les femelles que chez les hermaphrodites. Deux mécanismes mutuellement non exclusifs peuvent expliquer le maintien des femelles au sein de ces populations gynodioïques. D'une part, les femelles peuvent réallouer les ressources non utilisées pour la production de pollen et peuvent par conséquent produire plus d'ovules. D'autre part, la reproduction des femelles ne peut se faire que par allo-fécondation alors que les hermaphrodites, peuvent se reproduire à la fois par auto- et allo-fécondation. L'autofécondation s'accompagne en général d'une diminution de fitness de la descendance relativement à la progéniture issue d'allo-fécondation ; ce phénomène est connu sous le nom de dépression de consanguinité. Cette thèse avait pour but de mettre en évidence une éventuelle dépression de consanguinité chez Silene vulgaris, une espèce gynodioïque. Des hermaphrodites, issus de trois vallées alpines, ont été auto- et allo¬fécondés sur deux générations successives. La dépression de consanguinité pouvant s'exprimer à tous les stades de vie d'un individu, plusieurs traits de fitness, allant du nombre de graines par fruit à la production de gamètes ont été mesurés sur différents stades de vie successifs. L'estimation de la dépression de consanguinité totale atteignait des valeurs allant de 0.52 à 0.76 selon la vallée considérée, ce qui indiquerait que les hermaphrodites ont tout intérêt à limiter l'autofécondation et que les femelles ne devraient pas avoir de peine à subsister dans les vallées étudiées. Par la même occasion des mécanismes diminuant la purge potentielle du fardeau génétique, et permettant ainsi le maintien du « niveau » de dépression de consanguinité et par conséquence le maintien de la gynodïoécie ont été mis en évidence. En effet, nos résultats montrent que la dépression de consanguinité s'exprimait tard dans le cycle de vie permettant ainsi à un certain nombre individus consanguins de transmettre leurs allèles délétères à la génération suivante. D'autre part, la croissance in vivo des tubes polliniques d'auto-pollen était plus lente que celle de l'allo-pollen et donc en situation de compétition directe, les ovules devraient plutôt être issus d'allo-fécondation, diminuant ainsi les chances de purges d'allèles délétères. Enfin, l'apparition de femelles dans la progéniture d'hermaphrodites autofécondés diminue aussi les chances de purge d'allèles délétères. Il nous a été impossible de déterminer si l'apparition de femelles dans la descendance d'hermaphrodites autofécondés était due au déterminisme génétique du sexe ou si la différence de sexe ratio entre la descendance auto- et allo-fécondée était due à une éventuelle dépression de consanguinité inhibant la production de pollen. Nous avons observé que S. vulgaris ne présentaient pas uniquement des hermaphrodites et des femelles mais aussi toute sorte d'individus intermédiaires avec un nombre variable d'étamines viables. Nous avons pu mettre' en évidence des corrélations positives entre (1) la différence de sexe ratio (la proportion d'individus produisant du pollen) entre individus consanguins et non consanguins et une estimation de la dépression de consanguinité pour le nombre d'étamines viables d'individus produisant du pollen, ainsi qu'entre (2) la dépression de consanguinité pour le nombre d'étamines viables et celle estimée pour la viabilité du pollen. Chaque corrélation indique soit l'effet d'un (ou plusieurs) gène(s) pléiotropique(s), soit un déséquilibre de liaison entre les gènes. En considérant que ces corrélations sont le résultat d'effet pléiotropiques, la relation entre le nombre d'étamines viables par fleur et la viabilité du pollen, indiquerait un effet négatif de la consanguinité sur la production et la viabilité du pollen due partiellement à un gène majeur. La seconde corrélation indiquerait soit que les gènes responsables de la détermination du sexe agissent aussi sur l'expression de la fonction mâle soit que l'expression du sexe est sujette à la dépression de consanguinité, ou encore un mélange des deux. Aux regards de ces résultats, Silene vulgaris s'est avéré être un bon modèle de compréhension de l'évolution des systèmes de reproduction vers la séparation des sexes.

Effect of n-3 fatty acids on cerebral markers and the inflammatory response in sepsis

Introduction ICM+ software encapsulates our 20 years' experience in brain monitoring. It collects data from a variety of bedside monitors and produces time trends of parameters defi ned using confi gurable mathematical formulae. To date it is being used in nearly 40 clinical research centres worldwide. We present its application for continuous monitoring of cerebral autoregulation using near-infrared spectroscopy (NIRS). Methods Data from multiple bedside monitors are processed by ICM+ in real time using a large selection of signal processing methods. These include various time and frequency domain analysis functions as well as fully customisable digital fi lters. The fi nal results are displayed in a variety of ways including simple time trends, as well as time window based histograms, cross histograms, correlations, and so forth. All this allows complex information from bedside monitors to be summarized in a concise fashion and presented to medical and nursing staff in a simple way that alerts them to the development of various pathological processes. Results One hundred and fi fty patients monitored continuously with NIRS, arterial blood pressure (ABP) and intracranial pressure (ICP), where available, were included in this study. There were 40 severely headinjured adult patients, 27 SAH patients (NCCU, Cambridge); 60 patients undergoing cardiopulmonary bypass (John Hopkins Hospital, Baltimore) and 23 patients with sepsis (University Hospital, Basel). In addition, MCA fl ow velocity (FV) was monitored intermittently using transcranial Doppler. FV-derived and ICP-derived pressure reactivity indices (PRx, Mx), as well as NIRS-derived reactivity indices (Cox, Tox, Thx) were calculated and showed signifi cant correlation with each other in all cohorts. Errorbar charts showing reactivity index PRx versus CPP (optimal CPP chart) as well as similar curves for NIRS indices versus CPP and ABP were also demonstrated. Conclusions ICM+ software is proving to be a very useful tool for enhancing the battery of available means for monitoring cerebral vasoreactivity and potentially facilitating autoregulation guided therapy. Complexity of data analysis is also hidden inside loadable profi les, thus allowing investigators to take full advantage of validated protocols including advanced processing formulas.

Theoretical approach to the magnetostructural correlations in spin-Peierls compound CuGeO3

A theoretical density-functional study has been carried out to analyze the exchange coupling in the chains of CuGeO3 using discrete models. The results show a good agreement with the experimental exchange coupling constant (J) together with a strong dependence of J with the Cu-O-Cu angle. The calculation of the J values for a distorted model indicates a larger degree of dimerization than those reported previously.