1,697 research outputs found
Vortex Redistribution below the First-Order Transition Temperature in the \beta-Pyrochlore Superconductor KOs_2O_6
A miniature Hall sensor array was used to detect magnetic induction locally
in the vortex states of the -pyrochlore superconductor KOsO.
Below the first-order transition at K, which is associated
with a change in the rattling motion of K ions, the lower critical field and
the remanent magnetization both show a distinct decrease, suggesting that the
electron-phonon coupling is weakened below the transition. At high magnetic
fields, the local induction shows an unexpectedly large jump at
whose sign changes with position inside the sample. Our results demonstrate a
novel redistribution of vortices whose energy is reduced abruptly below the
first-order transition at .Comment: 5 pages, 4 figures, to be published in Phys. Rev. Let
Архаїчні рушники Півдня України (сюжети і семантика)
Groundwater is a life-sustaining resource that supplies water to
billions of people, plays a central part in irrigated agriculture
and influences the health of many ecosystems1,2. Most assessments
of global water resources have focused on surface water3–6, but
unsustainable depletion of groundwater has recently been
documented on both regional7,8 and global scales9–11. It remains
unclear how the rate of global groundwater depletion compares to
the rate of natural renewal and the supply needed to support
ecosystems. Here we define the groundwater footprint (the area
required to sustain groundwater use and groundwater-dependent
ecosystem services) and show that humans are overexploiting
groundwater in many large aquifers that are critical to agriculture,
especially in Asia and North America. We estimate that the size of
the global groundwater footprint is currently about 3.5 times the
actual area of aquifers and that about 1.7 billion people live in areas
where groundwater resources and/or groundwater-dependent
ecosystems are under threat. That said, 80 per cent of aquifers have
a groundwater footprint that is less than their area, meaning that
the net global value is driven by a few heavily overexploited
aquifers. The groundwater footprint is the first tool suitable for
consistently evaluating the use, renewal and ecosystem requirements
of groundwater at an aquifer scale. It can be combined
with the water footprint and virtual water calculations12–14, and
be used to assess the potential for increasing agricultural yields
with renewable groundwaterref15. The method could be modified
to evaluate other resources with renewal rates that are slow and
spatially heterogeneous, such as fisheries, forestry or soil
Концепция управления персоналом банка
Рассмотрены проблемы управления персоналом в коммерческих банках Украины в современных условиях перехода страны к рыночным отношениям. Даны предложения о том, что концепция работы с персоналом в Национальном банке может быть построена на взаимосвязи ее основных механизмов.Розглянуті проблеми управління персоналом в комерційних банках України в сучасних умовах переходу країни до ринкових відносин. Дані пропозиції про те, що концепція роботи з персоналом в Національному банку може бути побудований на взаємозв'язку її основних механізмів.The problems of personnel management in the commercial banks of Ukraine in the modern terms of transition of country to the market conditions are considered. Suggestions that conception of work with a personnel in the National bank can be built on intercommunication of its basic mechanisms are given
Vortex Solid-Liquid Transition in BiSrCaCuO with a High Density of Strong Pins
The introduction of a large density of columnar defects in %underdoped
BiSrCaCuO crystals does not, at sufficiently low
vortex densities, increase the irreversibility line beyond the first order
transition (FOT) field of pristine crystals. At such low fields, the flux line
wandering length behaves as in pristine
%BiSrCaCuO crystals. Next, vortex positional
correlations along the --axis in the vortex Bose glass at fields above the
FOT are smaller than in the low--field vortex solid. Third, the
Bose-glass-to-vortex liquid transition is signaled by a rapid decrease in
c-axis phase correlations. These observations are understood in terms of the
``discrete superconductor'' model.Comment: 4 pages, 4 figures Submitted to Phys. Rev. B Rapid Comm. 16-1-2004
Revised version 18-3-200
Magnetization Decay due to Vortex Phase Boundary Motion in BSCCO
We identify a new regime of decay of the irreversible magnetization in clean
BiSrCaCuO crystals, at induction values close to the
``second peak field'' at which the bulk critical current density steeply
increases. A time window is identified during which the decay of the induction
is controlled by the slow propagation of the phase transformation front across
the sample.Comment: 2 pages, 3 figures Paper submitted to the conference proceedings of
M2S-2000 Houston T
New High Field State of Flux Line Lattice in Unconventional Superconductor CeCoIn_5
Ultrasound velocity measurements of the unconventional superconductor
CeCoIn_5 with extremely large Pauli paramagnetic susceptibility reveal an
unusual structural transformation of the flux line lattice (FLL) in the
vicinity of the upper critical field. The transition field coincides with that
at which heat capacity measurements reveal a second order phase transition. The
lowering of the sound velocity at the transition is consistent with the
collapse of the FLL tilt modulus and a crossover to quasi two-dimensional FLL
pinning. These results provide a strong evidence that the high field state is
the Fulde-Ferrel-Larkin-Ovchinikov phase, in which the order parameter is
spatially modulated and has planar nodes aligned perpendicular to the vortices.Comment: 5 pages, 4 figure
Severe leptospirosis in a Dutch traveller returning from the Dominican Republic, October 2011
In October 2011, a case of leptospirosis was identified in a Dutch traveller returning from the Dominican Republic to the Netherlands. The 51-year-old man had aspired muddy water in the Chavón river on 29 September. Twenty days later he presented with fever, nausea, vomiting, diarrhoea, arthralgia, headache, conjunctival suffusion and icterus. Leptospira serovar Icterohaemorrhagiae or Australis infection was confirmed ten days later by laboratory testing
On Distributive Subalgebras of Qualitative Spatial and Temporal Calculi
Qualitative calculi play a central role in representing and reasoning about
qualitative spatial and temporal knowledge. This paper studies distributive
subalgebras of qualitative calculi, which are subalgebras in which (weak)
composition distributives over nonempty intersections. It has been proven for
RCC5 and RCC8 that path consistent constraint network over a distributive
subalgebra is always minimal and globally consistent (in the sense of strong
-consistency) in a qualitative sense. The well-known subclass of convex
interval relations provides one such an example of distributive subalgebras.
This paper first gives a characterisation of distributive subalgebras, which
states that the intersection of a set of relations in the subalgebra
is nonempty if and only if the intersection of every two of these relations is
nonempty. We further compute and generate all maximal distributive subalgebras
for Point Algebra, Interval Algebra, RCC5 and RCC8, Cardinal Relation Algebra,
and Rectangle Algebra. Lastly, we establish two nice properties which will play
an important role in efficient reasoning with constraint networks involving a
large number of variables.Comment: Adding proof of Theorem 2 to appendi
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