163 research outputs found
Sex differences in intimate relationships
Social networks have turned out to be of fundamental importance both for our
understanding human sociality and for the design of digital communication
technology. However, social networks are themselves based on dyadic
relationships and we have little understanding of the dynamics of close
relationships and how these change over time. Evolutionary theory suggests
that, even in monogamous mating systems, the pattern of investment in close
relationships should vary across the lifespan when post-weaning investment
plays an important role in maximising fitness. Mobile phone data sets provide
us with a unique window into the structure of relationships and the way these
change across the lifespan. We here use data from a large national mobile phone
dataset to demonstrate striking sex differences in the pattern in the
gender-bias of preferred relationships that reflect the way the reproductive
investment strategies of the two sexes change across the lifespan: these
differences mainly reflect women's shifting patterns of investment in
reproduction and parental care. These results suggest that human social
strategies may have more complex dynamics than we have tended to assume and a
life-history perspective may be crucial for understanding them.Comment: 5 pages, 3 figures, contains electronic supplementary materia
THE GENERAL SPATIAL SYSTEM OF ROCKY ENVIRONMENT FOR BUILDING PURPOSES
The paper summarizes and methodizes the necessary civil engineering knowledge for
the consideration of interaction between the construction and its rocky environment planned
from the point of view of both the construction and the earth's crust region. The rocky environment
of the construction has been formed under natural conditions. This determines its properties.
Models constructed by the selection of earth's crust elements of uniform properties and
by carrying out the necessary and possible generalizations serve to eyaluate the interactions
Autonomic SLA-Aware service virtualization for distributed systems
Cloud Computing builds on the latest achievements of diverse research areas, such as Grid Computing, Service-oriented computing, business processes and virtualization. Managing such heterogeneous environments requires sophisticated interoperation of adaptive coordinating components. In this paper we introduce an SLA-aware Service Virtualization architecture that provides non-functional guarantees in the form of Service Level Agreements and consists of a three-layered infrastructure including agreement negotiation, service brokering and on demand deployment. In order to avoid costly SLA violations, flexible and adaptive SLA attainment strategies are used with a failure propagation approach. We demonstrate the advantages of our proposed solution with a biochemical case study in a Cloud simulation environment. © 2011 IEEE
Different sensing mechanisms in single wire and mat carbon nanotubes chemical sensors
Chemical sensing properties of single wire and mat form sensor structures
fabricated from the same carbon nanotube (CNT) materials have been compared.
Sensing properties of CNT sensors were evaluated upon electrical response in
the presence of five vapours as acetone, acetic acid, ethanol, toluene, and
water. Diverse behaviour of single wire CNT sensors was found, while the mat
structures showed similar response for all the applied vapours. This indicates
that the sensing mechanism of random CNT networks cannot be interpreted as a
simple summation of the constituting individual CNT effects, but is associated
to another robust phenomenon, localized presumably at CNT-CNT junctions, must
be supposed.Comment: 12 pages, 5 figures,Applied Physics A: Materials Science and
Processing 201
Detection of fine-scale relationships between species composition and biomass in grassland
We elaborated and tested a novel operative framework for sampling and analysing fine-scale pattern of plant composition and biomass. We combined presence/absence sampling of plant species with non-destructive biomass estimation. In an open perennial sand grassland, we used 46 m long circular transects consisting of 0. 05 m by 0. 05 m adjoining elementary sampling units. This arrangement allows us to scale across a range of 0. 05 to 20 m. For measuring aboveground green biomass, we applied digital camera sensitive to red and near infrared parts of light spectrum, and we calculated normalised differential vegetation index (NDVI). We used information statistics proposed by Juhász-Nagy to study the association between spatial patterns of production and species composition. Since information statistical functions applied require binary data, we transformed NDVI data into one or several binary variables. We found that not only dominant species but subordinate gap species were also associated to high biomass, although the strength of association varied across scales. Most of the significant associations were detected at fine scales, from 0. 05 to 0. 25 m. At the scales commensurable with quadrat sizes usually applied in grasslands, i. e., from 0. 5 to 2. 0 m, we could hardly find any significant associations between species composition and biomass. We concluded that the novel methods applied proved reliable for studying fine-scale relationships between species composition and biomass
Bi-Laplacian Growth Patterns in Disordered Media
Experiments in quasi 2-dimensional geometry (Hele Shaw cells) in which a
fluid is injected into a visco-elastic medium (foam, clay or
associating-polymers) show patterns akin to fracture in brittle materials, very
different from standard Laplacian growth patterns of viscous fingering. An
analytic theory is lacking since a pre-requisite to describing the fracture of
elastic material is the solution of the bi-Laplace rather than the Laplace
equation. In this Letter we close this gap, offering a theory of bi-Laplacian
growth patterns based on the method of iterated conformal maps.Comment: Submitted to PRL. For further information see
http://www.weizmann.ac.il/chemphys/ander
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