1,225 research outputs found
Diversity of N2-fixing cyanobacteria from Andalusian paddy fields and analysis of their potential as bioinoculants
The marshes of the Guadalquivir River contain the largest area of rice cultivation in Spain, where more than 40,000 ha are used every year for rice production. These wetland areas provide a perfect place for rice cultivation, and represent a unique aquaticterrestrial habitat that hold more wintering waterfowl than any other European wetland.
Paddies require large amounts nitrogen and phosphorus for their growth, development and production. Though, flooded conditions used for rice cultivation drastically diminish efficiency inorganic nitrogen fertilizers, being only 30â40% used by the plant, and in some cases even less. Large amounts of nitrogen fertilizers are dissolved in the surface water and lost, causing environmental pollution and health problems due to losses through N2O and NO volatilization, denitrification, and leaching (Ishii et al., 2011)
How to Establish and Follow up a Large Prospective Cohort Study in the 21st Century - Lessons from UK COSMOS.
Large-scale prospective cohort studies are invaluable in epidemiology, but they are increasingly difficult and costly to establish and follow-up. More efficient methods for recruitment, data collection and follow-up are essential if such studies are to remain feasible with limited public and research funds. Here, we discuss how these challenges were addressed in the UK COSMOS cohort study where fixed budget and limited time frame necessitated new approaches to consent and recruitment between 2009-2012. Web-based e-consent and data collection should be considered in large scale observational studies, as they offer a streamlined experience which benefits both participants and researchers and save costs. Commercial providers of register and marketing data, smartphones, apps, email, social media, and the internet offer innovative possibilities for identifying, recruiting and following up cohorts. Using examples from UK COSMOS, this article sets out the dos and don'ts for today's cohort studies and provides a guide on how best to take advantage of new technologies and innovative methods to simplify logistics and minimise costs. Thus a more streamlined experience to the benefit of both research participants and researchers becomes achievable
Pretransitional phenomena in dilute crystals with first-order phase transition
Pretransitional phenomena at first-order phase transition in crystals diluted
by 'neutral' impurities (analogue of nonmagnetic atoms in dilute magnets) are
considered. It is shown that field dependence of order parameter becomes
nonanalytical in the stability region of the ordered phase, while smeared jumps
of thermodynamic parameters and anomalous (non-exponential) relaxation appear
near transition temperature of pure crystal.Comment: 4 page
Finite strain Landau theory of high pressure phase transformations
The properties of materials near structural phase transitions are often
successfully described in the framework of Landau theory. While the focus is
usually on phase transitions, which are induced by temperature changes
approaching a critical temperature T-c, here we will discuss structural phase
transformations driven by high hydrostatic pressure, as they are of major
importance for understanding processes in the interior of the earth. Since at
very high pressures the deformations of a material are generally very large,
one needs to apply a fully nonlinear description taking physical as well as
geometrical nonlinearities (finite strains) into account. In particular it is
necessary to retune conventional Landau theory to describe such phase
transitions. In Troster et al (2002 Phys. Rev. Lett. 88 55503) we constructed a
Landau-type free energy based on an order parameter part, an order
parameter-(finite) strain coupling and a nonlinear elastic term. This model
provides an excellent and efficient framework for the systematic study of phase
transformations for a wide range of materials up to ultrahigh pressures
Spatial variation and temporal trends of testicular cancer in Great Britain
Increases in testicular cancer incidence have been reported in several countries over a long period. Geographical variability has also been reported in some studies. We have investigated temporal trends and spatial variation of testicular cancer at ages 20â49 in Britain. Temporal trends in testicular cancer incidence were examined, 1974 to 1991 and in mortality, 1981â1997. Spatial variation in incidence was analysed across electoral wards, 1975 to 1991. We used Poisson regression to examine for regional and socio-economic effects and Bayesian mapping techniques to analyse small-area spatial variability. Incidence increased from 6.5 to 11.1 per 100â000 in men at ages 20â34, and from 5.6 to 9.7 per 100â000 in men at ages 35â49, while mortality declined by 50% in both age groups. Risks of testicular cancer varied across regional cancer registries, ranging from 0.79 (95% CI: 0.73â0.84) to 1.32 (95% CI: 1.25â1.38), and was higher in the most affluent compared with the most deprived areas. Analyses within 2 regions (one predominantly urban, the other predominantly rural) did not indicate any localized geographical clustering. The increasing incidence contrasted with a decreasing mortality over time in Great Britain, similar to that found in other countries. The higher risk in more affluent areas is not consistent with findings on social class at the individual level. The absence of any marked geographical variability at small area scale argues against a geographically varying environmental factor operating strongly in the aetiology of testicular cancer. © 2001 Cancer Research Campaign http://www.bjcancer.co
Ground state representations of loop algebras
Let g be a simple Lie algebra, Lg be the loop algebra of g. Fixing a point in
S^1 and identifying the real line with the punctured circle, we consider the
subalgebra Sg of Lg of rapidly decreasing elements on R. We classify the
translation-invariant 2-cocycles on Sg. We show that the ground state
representation of Sg is unique for each cocycle. These ground states correspond
precisely to the vacuum representations of Lg.Comment: 22 pages, no figur
Graduate dress code: How undergraduates are planning to use hair, clothes and make-up to smooth their transition to the workplace
This article explores the relationship between studentsâ identities, their ideas about professional appearance and their anticipated transition to the world of work. It is based on a series of semi-structured interviews with 13 students from a vocationally-focused university in England. It was found that participants viewed clothing and appearance as an important aspect of their transition to the workplace. They believed that, if carefully handled, their appearance could help them to fit in and satisfy the expectations of employers, although some participants anticipated that this process of fitting in might compromise their identity and values. The article addresses studentsâ anticipated means of handling the tension between adapting to a new environment and âbeing themselvesâ. It is argued that the way this process is handled is intertwined with wider facets of identity â most notably those associated with gender.The article is based on research funded by the University of Derby. © 2015 IP Publishing Ltd. ((http://www.ippublishing.com). Reproduced by permission
High-pressure phase and transition phenomena in ammonia borane NH3BH3 from X-ray diffraction, Landau theory, and ab initio calculations
Structural evolution of a prospective hydrogen storage material, ammonia
borane NH3BH3, has been studied at high pressures up to 12 GPa and at low
temperatures by synchrotron powder diffraction. At 293 K and above 1.1 GPa a
disordered I4mm structure reversibly transforms into a new ordered phase. Its
Cmc21 structure was solved from the diffraction data, the positions of N and B
atoms and the orientation of NH3 and BH3 groups were finally assigned with the
help of density functional theory calculations. Group-theoretical analysis
identifies a single two-component order parameter, combining ordering and
atomic displacement mechanisms, which link an orientationally disordered parent
phase I4mm with ordered distorted Cmc21, Pmn21 and P21 structures. We propose a
generic phase diagram for NH3BH3, mapping three experimentally found and one
predicted (P21) phases as a function of temperature and pressure, along with
the evolution of the corresponding structural distortions. Ammonia borane
belongs to the class of improper ferroelastics and we show that both
temperature- and pressure-induced phase transitions can be driven to be of the
second order. The role of N-H...H-B dihydrogen bonds and other intermolecular
interactions in the stability of NH3BH3 polymorphs is examined.Comment: 23 pages, 7 figure
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âIf you look the part youâll get the jobâ: should career professionals help clients to enhance their career image?
This article presents a critical exploration of the role of career professionals in supporting people to reflect on and enhance their appearance, attractiveness and self-presentation (career image). The article is conceptual and based on a review of the broader literature on career success, appearance and attractiveness. It explores the evidence for a relationship between attractiveness and career, and the authors propose a conceptual framework in which career image is comprised of three elements (interpersonal skills, aesthetic presentation and beauty). The paper examines a possible role for career professionals in relation to this and then critically examines this role and concludes with the proposition of a research agenda in this area
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