743 research outputs found
Support to organic farming and bio-energy as rural development drivers
The paper conducts an analysis of the potentials of organic farming and bioenergy as win-win-win strategies promoting economic growth, employment and the environment at the same time. Empirical evidence does not indicate that conversion to organic farming will enhance economic growth and employment, but there are environmental benefits primarily due to the absence of pesticides. If energy crops are grown on idle land bioenergy has the potential of generating economic activities and employment alongside with CO2 reductions. Liquid biofuel production is a relatively expensive way of reducing CO2, but there is a potential for technological breakthroughs making it economically viable to use low value feedstock like straw and waste for bioethanol production. It is recommended that the positive environmental effects of organic farming and bioenergy are internalised through green taxes on the negative externalities from conventional farming and fossil energy use
From the macroscopic to the microscopic: some scientific insights
The full report in which this chapter appears is in ORE: http://hdl.handle.net/10871/1416
Thermodynamics of O(N) sigma models: 1/N corrections
The thermodynamics of the O(N) linear and nonlinear sigma models in 3+1
dimensions is studied. We calculate the pressure to next-to-leading order in
the 1/N expansion and show that at this order, temperature-independent
renormalization is only possible at the minimum of the effective potential. The
1/N expansion is found to be a good expansion for N as low as 4, which is the
case relevant for low-energy QCD phenomenology. We consider the cases with and
without explicit symmetry breaking. We show that previous next-to-leading order
calculations of the pressure are either breaking down in the temperatures of
interest, or based on unjustifiable high-energy approximations.Comment: 11 pages, 5 figures, revte
Mass Expansions of Screened Perturbation Theory
The thermodynamics of massless phi^4-theory is studied within screened
perturbation theory (SPT). In this method the perturbative expansion is
reorganized by adding and subtracting a mass term in the Lagrangian. We
analytically calculate the pressure and entropy to three-loop order and the
screening mass to two-loop order, expanding in powers of m/T. The truncated
m/T-expansion results are compared with numerical SPT results for the pressure,
entropy and screening mass which are accurate to all orders in m/T. It is shown
that the m/T-expansion converges quickly and provides an accurate description
of the thermodynamic functions for large values of the coupling constant.Comment: 22 pages, 10 figure
Identification of miRNA targets with stable isotope labeling by amino acids in cell culture
miRNAs are small noncoding RNAs that regulate gene expression. We have used stable isotope labeling by amino acids in cell culture (SILAC) to investigate the effect of miRNA-1 on the HeLa cell proteome. Expression of 12 out of 504 investigated proteins was repressed by miRNA-1 transfection. This repressed set of genes significantly overlaps with miRNA-1 regulated genes that have been identified with DNA array technology and are predicted by computational methods. Moreover, we find that the 3′-untranslated region for the repressed set are enriched in miRNA-1 complementary sites. Our findings demonstrate that SILAC can be used for miRNA target identification and that one highly expressed miRNA can regulate the levels of many different proteins
Eclipsing Binaries in Open Clusters
Detached eclipsing binaries are very useful objects for calibrating
theoretical stellar models and checking their predictions. Detached eclipsing
binaries in open clusters are particularly important because of the additional
constraints on their age and chemical composition from their membership of the
cluster. I compile a list containing absolute parameters of well-studied
eclipsing binaries in open clusters, and present new observational data on the
B-type systems V1481 Cyg and V2263 Cyg which are members of the young open
cluster NGC 7128.Comment: 4 pages, 2 colour figures. Poster presentation for IAUS 240 (Binary
Stars as Critical Tools and Tests in Contemporary Astrophysics), Prague,
August 2006. The poster itself can be dowloaded in ppt and pdf versions from
http://www.astro.keele.ac.uk/~jkt/pubs.htm
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