1,155 research outputs found
Population dynamics of Ichthyophthirius Multifiliis
Imperial Users onl
The current panorama of European Network of Earth Observation Networks and the need for an European Network of Networks - ENEON
ENEON is the European Network of Earth Observation Networks, funded by the European Union under the H2020ConnectinGEO project mainly including non-space networks to better coordinate them, with the aim of providing better observations for resolving interdisciplinary problems, to improve the European in-situ participation in GEO and in support of the implementation and monitoring of the UN Sustainable Development Goals
Low-Temperature Rapid Synthesis and Superconductivity of Fe-Based Oxypnictide Superconductors
we were able to develop a novel method to synthesize Fe-based oxypnictide
superconductors. By using LnAs and FeO as the starting materials and a
ball-milling process prior to solid-state sintering, Tc as high as 50.7 K was
obtained with the sample of Sm 0.85Nd0.15FeAsO0.85F0.15 prepared by sintering
at temperatures as low as 1173 K for times as short as 20 min.Comment: 2 pages,2 figures, 1 tabl
High superconducting anisotropy and weak vortex pinning in Co doped LaFeAsO
Here, we present an electrical transport study in single crystals of
LaFeCoAsO ( K) under high magnetic fields. In
contrast to most of the previously reported Fe based superconductors, and
despite its relatively low , LaFeCoAsO shows a superconducting
anisotropy which is comparable to those seen for instance in the cuprates or
, where
is the effective mass anisotropy. Although, in the present case and as in all
Fe based superconductors, as . Under
the application of an external field, we also observe a remarkable broadening
of the superconducting transition particularly for fields applied along the
inter-planar direction. Both observations indicate that the low dimensionality
of LaFeCoAsO is likely to lead to a more complex vortex
phase-diagram when compared to the other Fe arsenides and consequently, to a
pronounced dissipation associated with the movement of vortices in a possible
vortex liquid phase. When compared to, for instance, F-doped compounds
pertaining to same family, we obtain rather small activation energies for the
motion of vortices. This suggests that the disorder introduced by doping
LaFeAsO with F is more effective in pinning the vortices than alloying it with
Co.Comment: 7 figures, 7 pages, Phys. Rev. B (in press
Probing fractal magnetic domains on multiple length scales in Nd2Fe14B
Using small-angle neutron scattering, we demonstrate that the complex
magnetic domain patterns at the surface of Nd2Fe14B, revealed by quantitative
Kerr and Faraday microscopy, propagate into the bulk and exhibit structural
features with dimensions down to 6 nm, the domain wall thickness. The observed
fractal nature of the domain structures provides an explanation for the
anomalous increase in the bulk magnetization of Nd2Fe14B below the
spin-reorientation transition. These measurements open up a rich playground for
studies of fractal structures in highly anisotropic magnetic systems.Comment: Accepted for publication in Phys. Rev. Lett. (4 pages, 4 figures
Highlighting continued uncertainty in global land cover maps for the user community
In the last 10 years a number of new global datasets have been created and new, more sophisticated alorithms have been designed to classify land cover. GlobCover and MODIS v.5 are the most recent global land cover products available, where GlobCover (300 m) has the finest spatial resolution of other comparable products such as MODIS v.5 (50 m) and GLC-2000 (1 km). This letter shows that the thematic accuracy in the cropland domain has decreased when comparing these two latest products. This disagreement is also evident spatially when examining maps of cropland and forest disargeement between GLC-2000, MODIS and GlobCover. The analysis highlights the continued uncertainty surrounding these prducts, with a combined forest and cropland disagreement of 893 Mha (GlobCover versus MODIS v.5). This letter suggests that data sharing efforts and the provision of more 'in situ' data for training, calibration and validation are very important conditions for improving future global land cover products
Suitable and optimal locations for implementing photovoltaic water pumping systems for grassland irrigation in China
Grassland plays a key role for the food security of China because of the large number of livestock raised in those areas. Thus, grassland degradation due to climate change and overgrazing is considered as one of the most severe environmental and economic threat for the future sustainable development of China. Photovoltaic water pumping systems for irrigation can play a fundamental role for the conservation of grassland areas.
This paper investigates the geospatial distribution of the technically suitable grassland locations for the implementation of photovoltaic water pumping systems. The technically suitable grassland areas were taken as starting point to assess the optimal locations. The assessment of the optimal locations was conducted using a spatially explicit optimization model of renewable energy systems based on the cost minimization of the whole forage supply chain.
The results indicate that the photovoltaic water pumping systems provide high potential for improving forage productivity, contributing to meet the local demand. the optimal areas are highly sensitive to several environmental and economic parameters such as increased forage potential yield, forage management costs, forage water requirements, ground water depth, forage price and CO2. Most of the optimal areas are selected when the market forage price ranges from 300 to 500 $/tonne DM, indicating that the forage produced using PVWP technology for irrigation is already competitive compared to the imported forage
Operationalizing Resilience Against Natural Disaster Risk: Opportunities, Barriers, and a Way Forward
The risks from floods have been rising globally due to increasing population, urbanization and economic development in hazard prone areas. The number of flood disasters throughout the world nearly doubled in the decade from 2000-2009 compared to the previous decade. There have been more flood disasters in the last four years (2010-2013) than in the whole decade of the 1980's. Evidence indicates that climate change-induced sea level rise, storm surge and more intense flooding will reinforce this trend unless risk management measures are undertaken immediately to well manage future losses and make communities more resilient to flooding.
It is widely recognized that there is a mutually reinforcing relationship between disaster risk and development: disasters impact development and development impacts disasters. Evidence shows that repeated disasters undermine long-term socio-economic objectives. This is particularly evident in low income countries where disasters can impede the development process. The extensive time required to recover from damage, loss of capacity with which to rebuild and systemic risk negatively affect livelihoods in these countries, in the extreme case trapping people in poverty. In developed countries, recent floods triggered massive economic losses and undermined long-term competitiveness. The impact of disasters is felt most acutely by households and communities. In both developing and developed countries alike, local level studies strongly indicate that the poor suffer disproportionately due to the lack of financial and social safety nets, and institutional representation. Development can affect disaster risk via three main channels: by (1) increasing the physical assets and people exposed to the risk, (2) increasing the capacity to reduce the risk, respond to the risk and recover from the risk and (3) increasing or decreasing the vulnerability based on specific development strategies chosen. We identify this interaction as a key research gap; taking account of and balancing development opportunities with disaster risk will require a paradigm shift in the way we think about and do both development and disaster risk management
Brazilian spring wheat germplasm as source of genetic variability.
As part of a Canada-Brazil germplasm exchange, 106 modern and ancient Brazilian spring wheat cultivars have been genotyped and phenotypically evaluated in Canada since 201
Formation of heavy quasiparticle state in two-band Hubbard model
A realization of heavy fermion state is investigated on the basis of two-band
Hubbard model. By means of the slave-boson mean-field approximation, it is
shown that for the intermediate electron density, n_e=1.5, the inter-band
Coulomb repulsion U strongly emphasizes initially small difference between
bands, and easily stabilizes integral valence in the lower band. As a result, a
strong renormalization takes place in the lower band and the mixing strength
between two bands. It gives rise to a sharp peak at the Fermi level in the
quasiparticle density of states, as that obtained in the periodic Anderson
model. In contrast to a simple insight that the Hund's-rule coupling J reduces
the characteristic energy, it turns out to be almost irrelevant to the
renormalization for J<U. The required conditions are suitable for LiV_2O_4, the
first observed heavy fermion compound in transition metal oxide.Comment: 5 pages, 4 figures, to be published in Phys. Rev.
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