6,131 research outputs found
Study of Giant Pairing Vibrations with neutron-rich nuclei
We investigate the possible signature of the presence of giant pairing states
at excitation energy of about 10 MeV via two-particle transfer reactions
induced by neutron-rich weakly-bound projectiles. Performing particle-particle
RPA calculations on Pb and BCS+RPA calculations on Sn, we
obtain the pairing strength distribution for two particles addition and removal
modes. Estimates of two-particle transfer cross sections can be obtained in the
framework of the 'macroscopic model'. The weak-binding nature of the projectile
kinematically favours transitions to high-lying states. In the case of (~^6He,
\~^4He) reaction we predict a population of the Giant Pairing Vibration with
cross sections of the order of a millibarn, dominating over the mismatched
transition to the ground state.Comment: Talk presented in occasion of the VII School-Semina r on Heavy Ion
Physics hosted by the Flerov Laboratory (FLNR/JINR) Dubna, Russia from May 27
to June 2, 200
Environmental factors influence both abundance and genetic diversity in a widespread bird species.
Genetic diversity is one of the key evolutionary variables that correlate with population size, being of critical importance for population viability and the persistence of species. Genetic diversity can also have important ecological consequences within populations, and in turn, ecological factors may drive patterns of genetic diversity. However, the relationship between the genetic diversity of a population and how this interacts with ecological processes has so far only been investigated in a few studies. Here, we investigate the link between ecological factors, local population size, and allelic diversity, using a field study of a common bird species, the house sparrow (Passer domesticus). We studied sparrows outside the breeding season in a confined small valley dominated by dispersed farms and small-scale agriculture in southern France. Population surveys at 36 locations revealed that sparrows were more abundant in locations with high food availability. We then captured and genotyped 891 house sparrows at 10 microsatellite loci from a subset of these locations (N = 12). Population genetic analyses revealed weak genetic structure, where each locality represented a distinct substructure within the study area. We found that food availability was the main factor among others tested to influence the genetic structure between locations. These results suggest that ecological factors can have strong impacts on both population size per se and intrapopulation genetic variation even at a small scale. On a more general level, our data indicate that a patchy environment and low dispersal rate can result in fine-scale patterns of genetic diversity. Given the importance of genetic diversity for population viability, combining ecological and genetic data can help to identify factors limiting population size and determine the conservation potential of populations
Adaptive latitudinal variation in Common Blackbird Turdus merula nest characteristics
Nest construction is taxonomically widespread, yet our understanding of adaptive
intraspecific variation in nest design remains poor. Nest characteristics are
expected to vary adaptively in response to predictable variation in spring temperatures
over large spatial scales, yet such variation in nest design remains largely
overlooked, particularly amongst open-cup-nesting birds. Here, we systematically
examined the effects of latitudinal variation in spring temperatures and precipitation
on the morphology, volume, composition, and insulatory properties of
open-cup-nesting Common Blackbirds’ Turdus merula nests to test the hypothesis
that birds living in cooler environments at more northerly latitudes would build
better insulated nests than conspecifics living in warmer environments at more
southerly latitudes. As spring temperatures increased with decreasing latitude, the
external diameter of nests decreased. However, as nest wall thickness also
decreased, there was no variation in the diameter of the internal nest cups. Only
the mass of dry grasses within nests decreased with warmer temperatures at lower
latitudes. The insulatory properties of nests declined with warmer temperatures at
lower latitudes and nests containing greater amounts of dry grasses had higher insulatory
properties. The insulatory properties of nests decreased with warmer temperatures
at lower latitudes, via changes in morphology (wall thickness) and
composition (dry grasses). Meanwhile, spring precipitation did not vary with latitude,
and none of the nest characteristics varied with spring precipitation. This suggests
that Common Blackbirds nesting at higher latitudes were building nests with
thicker walls in order to counteract the cooler temperatures. We have provided evidence
that the nest construction behavior of open-cup-nesting birds systematically
varies in response to large-scale spatial variation in spring temperatures
Highly-Parallel, Highly-Compact Computing Structures Implemented in Nanotechnology
In this paper, we describe work in which we are evaluating how the evolving properties of nano-electronic devices could best be utilized in highly parallel computing structures. Because of their combination of high performance, low power, and extreme compactness, such structures would have obvious applications in spaceborne environments, both for general mission control and for on-board data analysis. However, the anticipated properties of nano-devices mean that the optimum architecture for such systems is by no means certain. Candidates include single instruction multiple datastream (SIMD) arrays, neural networks, and multiple instruction multiple datastream (MIMD) assemblies
Direct Immunosensor Design Based on the Electrochemical Reduction of 4-((4-Nitrophenyl) ethynyl) benzenethiol Monolayers
The synthesis and characterization of novel N-arylhydroxylamine-based molecular wires are described for use in the site-directed covalent immobilization of whole IgG antibodies onto gold electrode surfaces. The hydroxylamine, electrochemically generated in situ from reduction of the corresponding nitrobenzene, is stable under a wide range of solution conditions and reacts selectively with carbohydrate away from the antibody-binding site to allow the development of immunosensors with maximal activity. Cyclic voltammetric responses have shown a direct correlation between the structure and length of the molecular wire and its stability and concentration at the electrode surface
Understanding the differences of integrating building performance simulation in the architectural education system
In order to assist tertiary architectural education institutions as well as the architecture profession in developing course material and training packages related to Building Performance Simulation (BPS), we present
the outcome of a survey conducted in Australia, India, the US and the UK. The main objective of the survey was to investigate how BPS is taught at a number of different architecture schools at universities in these countries and to point out potential difficulties and barriers. Based on the survey, the paper proposes a number of recommendations and highlights
opportunities for future degree schemes that develop module content and learning objectives/ outcome for teaching BPS at architectural tertiary educational institutions.Christina J. Hopfe, Veronica Soebarto, Dru Crawley, Rajan Rawa
Biosensors for the monitoring of harmful algal blooms
Peer Reviewed Paper.
DOI: https://doi.org/10.1016/j.copbio.2017.02.018
Citation: McPartlin, D. A., Loftus, J. H., Crawley, A. S., Silke, J., Murphy, C. S., & O’Kennedy, R. J. (2017). Biosensors for the monitoring of harmful algal blooms. Current Opinion in Biotechnology, 45, 164–169. https://doi.org/10.1016/j.copbio.2017.02.018Harmful algal blooms (HABs) are a major global concern due to their propensity to cause environmental damage, healthcare issues and economic losses. In particular, the presence of toxic phytoplankton is a cause for concern. Current HAB monitoring programs often involve laborious laboratory-based analysis at a high cost and with long turnaround times. The latter also hampers the potential to develop accurate and reliable models that can predict HAB occurrence. However, a promising solution for this issue may be in the form of remotely deployed biosensors, which can rapidly and continuously measure algal and toxin levels at the point-of-need (PON), at a low cost. This review summarises the issues HABs present, how they are difficult to monitor and recently developed biosensors that may improve HAB-monitoring challenges
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