Living bacteria rheology: population growth, aggregation patterns and cooperative behaviour under different shear flows

The activity of growing living bacteria was investigated using real-time and in situ rheology -- in stationary and oscillatory shear. Two different strains of the human pathogen Staphylococcus aureus -- strain COL and its isogenic cell wall autolysis mutant -- were considered in this work. For low bacteria density, strain COL forms small clusters, while the mutant, presenting deficient cell separation, forms irregular larger aggregates. In the early stages of growth, when subjected to a stationary shear, the viscosity of both strains increases with the population of cells. As the bacteria reach the exponential phase of growth, the viscosity of the two strains follow different and rich behaviours, with no counterpart in the optical density or in the population's colony forming units measurements. While the viscosity of strain COL keeps increasing during the exponential phase and returns close to its initial value for the late phase of growth, where the population stabilizes, the viscosity of the mutant strain decreases steeply, still in the exponential phase, remains constant for some time and increases again, reaching a constant plateau at a maximum value for the late phase of growth. These complex viscoelastic behaviours, which were observed to be shear stress dependent, are a consequence of two coupled effects: the cell density continuous increase and its changing interacting properties. The viscous and elastic moduli of strain COL, obtained with oscillatory shear, exhibit power-law behaviours whose exponent are dependent on the bacteria growth stage. The viscous and elastic moduli of the mutant have complex behaviours, emerging from the different relaxation times that are associated with the large molecules of the medium and the self-organized structures of bacteria. These behaviours reflect nevertheless the bacteria growth stage.Comment: 9 pages, 10 figure

Explaining engagement levels of opportunity and necessity entrepreneurs

This paper investigates differences between opportunity and necessity entrepreneurs in terms of socio-demographics, attitudes and perception of obstacles . We use the 2004 Flash Eurobarometer Survey data. Explanatory variables include gender, age, education level and self-employed parents, risk tolerance, locus of control, perceptions of four obstacles and country effects. The obstacle variables include the perception of availibility of financial support; administrative complexity; of access to information on new venture creation and an unfavorable economic climate. Using probit equations we investigate differences in the preference for self-employment of opportunity and necessity entrepreneurs. A probit equation is estimated relating the explanatory variables to opportunity versus necessity entrepreneurship. Moreover, differences in the entrepreneurial engagement of opportunity and necessity entrepreneurs are investigated on the basis of a (ordered) multinomial logit model. Findings indicate that opportunity entrepreneurs have a higher preference for self-employment because of family encouragement. Also, opportunity entrepreneurs are found to perceive of administrative complexity and an unfavorable economic climate, negatively influencing their entrepreneurial involvement, while this is not the case for necessity entrepreneurs

Treatment of Nonmotor Symptoms in Parkinson's Disease

Nonmotor symptoms (NMS) are integral to Parkinson's disease (PD) and the management can often be challenging. In spite of the growing evidence that NMS have a key impact on the quality of life of patients and caregivers, most clinical trials still focus on motor symptoms as primary outcomes. As a consequence strong evidence-based treatment recommendations for NMS occurring in PD are spare. In this chapter, the current data addressing the treatment of major NMS such as sleep, cognitive and autonomic dysfunction, and depression and anxiety are described

Increasing Dominance - the Role of Advertising, Pricing and Product Design

Despite the empirical relevance of advertising strategies in concentrated markets, the economics literature is largely silent on the effect of persuasive advertising strategies on pricing, market structure and increasing (or decreasing) dominance. In a simple model of persuasive advertising and pricing with differentiated goods, we analyze the interdependencies between ex-ante asymmetries in consumer appeal, advertising and prices. Products with larger initial appeal to consumers will be advertised more heavily but priced at a higher level - that is, advertising and price discounts are strategic substitutes for products with asymmetric initial appeal. We find that the escalating effect of advertising dominates the moderating effect of pricing so that post-competition market shares are more asymmetric than pre-competition differences in consumer appeal. We further find that collusive advertising (but competitive pricing) generates the same market outcomes, and that network effects lead to even more extreme market outcomes, both directly and via the effect on advertising

How do major roads affect Barn Owls? Distributin, space use, food source and mortality

Road network expansion is known as one of the main factors responsible for the decline of Barn Owl (Tyto alba) populations in Europe, although the full causes of this decline are still poorly understood. In this context we evaluated several issues related to Barn Owl\u2019s ecology, in Southern Portugal, when interacting with major roads: (a) the effect of highway distance on owl\u2019s occurrence pattern, (b) the behavioral in the vicinity of major roads, (c) the role of road verges as an attraction factor due to prey abundance, and (d) owls\u2019 spatial and temporal patterns of road mortality. To assess species occurrence (presence/absence) we broadcasted Barn Owl adult calls in 122 sites at several distances from major roads and detected 47 individuals. From the set of environmental and road-related variables tested using logistic regression, only the distance to the highway showed a significant positive influence on Barn Owl presence (\u3b2= 0.995; p<0.05). Space use patterns and road crossing rates were investigated on the basis of seven radio-tagged individuals (4 &42, 3 &40), captured in their nests located close to the highway (<5 km). The crossing rate was low (one road crossing per 34.19 hours of radio-tracking). Of the tracked individuals only four (3 &42, 1 &40) had sample sizes strong enough to provide robust estimates of home-range size (Fixed Kernel Density Estimator 95%) and just a peripheral overlap between homeranges (ranging from 2.61 km2 to 9.37 km2) and the highway was observed. The overall abundance of small mammals, assessed through live-trapping, was significantly higher in highway verges (n=248) than in the two other dominant land uses (cork oak woodlands (n=35), and croplands (n=64), suggesting that road verges could be a suitable habitat for hunting. Between 2004 and 2007, 373 road-kills were detected in 314 km of national roads surveyed (0.30 Barn Owls kills.km-1.year-1). A higher number of casualties was registered in fall and winter months when the dispersion of juveniles occurs, while lower mortality frequencies were detected in the end of summer and early spring, corresponding to hatching and fledgling periods. Mortality hotspots revealed to be strongly related with altitude (\u3b2 =-0.026; p<0.05), eucalyptus or pine forest cover (\u3b2 =-0.001; p<0.05) and percentage of cropland areas crossed by the road (\u3b2 =0.332; p<0.05). Although major roads do not seem to act as effective barriers to Barn Owls\u2019 movements, their occurrence pattern is significantly affected by this linear structure. Moreover, the potential attraction effect due to higher prey density in the highway verges does not seem to have an effect in the foraging behavior of adults

Associations of physical activity with body weight and fat in men and women

OBJECTIVE: Increasing physical activity is strongly advocated as a key public health strategy for weight gain prevention. We investigated associations of leisure-time physical activity (LTPA) and occupational/domestic physical activity with body mass index (BMI) and a skinfold-derived index of body fat (sum of six skinfolds), among normal-weight and overweight men and women.DESIGN: Analyses of cross-sectional self-report and measured anthropometric data.SUBJECTS: A total of 1302 men and women, aged 18-78 y, who were part of a randomly selected sample and who agreed to participate in a physical health assessment.MEASUREMENTS: Self-report measures of physical activity, measured height and weight, and a skinfold-derived index of body fatness.RESULTS: Higher levels of LTPA were positively associated with the likelihood of being in the normal BMI and lower body fat range for women, but few or no associations were found for men. No associations were found between measures of occupational/domestic activity and BMI or body fat for men or women.CONCLUSION: By using a skinfold sum as a more direct measure of adiposity, this study extends and confirms the previous research that has shown an association between BMI and LTPA. Our results suggest gender differences in the relationship of leisure-time physical activity with body fatness. These findings, in conjunction with a better understanding of the causes of such differences, will have important public health implications for the development and targeting of weight gain prevention strategies.<br /

The entrepreneurial ladder, gender, and regional development

Gender differences at five levels of entrepreneurial engagement are explained using country effects while controlling for individual-level variables. We distinguish between individuals who have never considered starting up a business, those who are thinking about it, and nascent, young, and established entrepreneurs. We use a large international dataset that includes respondents from 32 European countries, three Asian countries, and the United States. Findings show that cross-country gender differences are largest in the first and final transitions of the entrepreneurial process. In par

Outlining a new collaborative business model as a result of the green Building Information Modelling impact in the AEC supply chain

BIM (Building Information Modelling) technological push has enabled to integrate the design/construction outcomes of 3D-CAD along the product/service AEC (Architecture, Engineering and Construction) SC (supply chain) through an intelligent DMS (Data Management System) based on standard and interoperable data formats. The proposed end-to-end approach overcomes a typical AEC gap, enables the operationalisation of the sustainable/green building LCA (Life Cycle Assessment) and puts together new collaborative relationships with the owner, among SC stakeholders and with new forms of BIM procurement. The outlined collaborative business model is based on the Quality Control and Assurance framework and provides conceptual consistency to the reintroduction of the owner concerns/satisfaction in the SC, as well as enables consistent and accountable relationships between (smart)materials procurement and building specification. An expert’s focus group carried out a preliminary check of the model’s interest/applicability, resulting in recommendations for its further detailing and for propositions development into a systematic enquiring process.info:eu-repo/semantics/acceptedVersio