818 research outputs found
Wound Complications Following Resection of Adductor Compartment Tumours
Purpose Limb salvage surgery of soft tissue sarcomas is associated with both a risk of local recurrence and wound complications.
Although the lower limb appears to be at greater risk of wound-related morbidity, few studies separate anatomical
compartments. We believe that the adductor compartment of the thigh has a particularly high rate of complications and so
performed a retrospective analysis of all soft tissue sarcomas arising in this region undergoing limb salvage
Momentum dependence of the superconducting gap in NdFeAsO1-xFx single crystals measured by angle resolved photoemission spectroscopy
We use angle resolved photoemission spectroscopy (ARPES) to study the
momentum dependence of the superconducting gap in NdFeAsO1-xFx single crystals.
We find that the Gamma hole pocket is fully gapped below the superconducting
transition temperature. The value of the superconducting gap is 15 +- 1.5 meV
and its anisotropy around the hole pocket is smaller than 20% of this value.
This is consistent with an isotropic or anisotropic s-wave symmetry of the
order parameter or exotic d-wave symmetry with nodes located off the Fermi
surface sheets. This is a significant departure from the situation in the
cuprates, pointing to possibility that the superconductivity in the iron
arsenic based system arises from a different mechanism.Comment: 4 pages, 3 figure
Flexible provisioning of Web service workflows
Web services promise to revolutionise the way computational resources and business processes are offered and invoked in open, distributed systems, such as the Internet. These services are described using machine-readable meta-data, which enables consumer applications to automatically discover and provision suitable services for their workflows at run-time. However, current approaches have typically assumed service descriptions are accurate and deterministic, and so have neglected to account for the fact that services in these open systems are inherently unreliable and uncertain. Specifically, network failures, software bugs and competition for services may regularly lead to execution delays or even service failures. To address this problem, the process of provisioning services needs to be performed in a more flexible manner than has so far been considered, in order to proactively deal with failures and to recover workflows that have partially failed. To this end, we devise and present a heuristic strategy that varies the provisioning of services according to their predicted performance. Using simulation, we then benchmark our algorithm and show that it leads to a 700% improvement in average utility, while successfully completing up to eight times as many workflows as approaches that do not consider service failures
Landscape transformations produce favorable roosting conditions for turkey vultures and black vultures
Recent increases in turkey vulture (Cathartes aura) and black vulture (Coragyps atratus) populations in North America have been attributed in part to their success adapting to human-modified landscapes. However, the capacity for such landscapes to generate favorable roosting conditions for these species has not been thoroughly investigated. We assessed the role of anthropogenic and natural landscape elements on roosting habitat selection of 11 black and 7 turkey vultures in coastal South Carolina, USA using a GPS satellite transmitter dataset derived from previous research. Our dataset spanned 2006–2012 and contained data from 7916 nights of roosting. Landscape fragmentation, as measured by land cover richness, influenced roosting probability for both species in all seasons, showing either a positive relationship or peaking at intermediate values. Roosting probability of turkey vultures was maximized at intermediate road densities in three of four seasons, and black vultures showed a positive relationship with roads in fall, but no relationship throughout the rest of the year. Roosting probability of both species declined with increasing high density urban cover throughout most of the year. We suggest that landscape transformations lead to favorable roosting conditions for turkey vultures and black vultures, which has likely contributed to their recent proliferations across much of the Western Hemisphere
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An approach to melodic segmentation and classification based on filtering with the Haar wavelet
We present a novel method of classification and segmentation of melodies in symbolic representation. The method is based on filtering pitch as a signal over time with the Haar-wavelet, and we evaluate it on two tasks. The filtered signal corresponds to a single-scale signal ws from the continuous Haar wavelet transform. The melodies are first segmented using local maxima or zero-crossings of ws. The
segments of ws are then classified using the k–nearest neighbour algorithm with Euclidian and city-block distances. The method proves more effective than using unfiltered pitch signals and Gestalt-based segmentation when used to recognize the parent works of segments from Bach’s Two-Part Inventions (BWV 772–786). When used to classify 360 Dutch folk tunes into 26 tune families, the performance of the
method is comparable to the use of pitch signals, but not as good as that of string-matching methods based on multiple features
Thermal tides in the Martian middle atmosphere as seen by the Mars Climate Sounder
The first systematic observations of the middle atmosphere of Mars (35–80km) with the Mars Climate Sounder (MCS) show dramatic patterns of diurnal thermal variation, evident in retrievals of temperature and water ice opacity. At the time of writing, the data set of MCS limb retrievals is sufficient for spectral analysis within a limited range of latitudes and seasons. This analysis shows that these thermal variations are almost exclusively associated with a diurnal thermal tide. Using a Martian general circulation model to extend our analysis, we show that the diurnal thermal tide dominates these patterns for all latitudes and all seasons
Evidence for Supercurrent Connectivity in Conglomerate Particles in NdFeAsO1-d
Here we use global and local magnetometry and Hall probe imaging to
investigate the electromagnetic connectivity of the superconducting current
path in the oxygen-deficient fluorine-free Nd-based oxypnictides. High
resolution transmission electron microscopy and scanning electron microscopy
show strongly-layered crystallites, evidence for a ~ 5nm amorphous oxide around
individual particles, and second phase neodymium oxide which may be responsible
for the large paramagnetic background at high field and at high temperatures.
From global magnetometry and electrical transport measurements it is clear
that there is a small supercurrent flowing on macroscopic sample dimensions
(mm), with a lower bound for the average (over this length scale) critical
current density of the order of 103 A/cm2. From magnetometry of powder samples
and local Hall probe imaging of a single large conglomerate particle ~120
microns it is clear that on smaller scales, there is better current
connectivity with a critical current density of the order of 5 x 104 A/cm2. We
find enhanced flux creep around the second peak anomaly in the magnetisation
curve and an irreversibility line significantly below Hc2(T) as determined by
ac calorimetry.Comment: 11 pages, 4 figure
Determination of angiotensin I-converting enzyme activity in equine blood: lack of agreement between methods of analysis
Angiotensin-I converting enzyme (ACE) is a key regulator of blood pressure, electrolytes and fluid homeostasis through conversion of angiotensin I into angiotensin II. Recently, a genetic polymorphism of the ACE gene, which accounts for 47% of the variation of ACE activity in blood, has been advocated as a biomarker of athletic aptitude. Different methods of analysis and determination of ACE activity in plasma have been used in human and equine research without a consensus of a "gold standard" method. Different methods have often been used interchangeably or cited as being comparable in the existing literature; however, the actual agreement between assays has not been investigated. Therefore, in this study, we evaluated the level of agreement between three different assays using equine plasma obtained from 29 horses. Two spectrophotometric assays using Furylacryloyl-phenylalanyl-glycyl-glycine as substrate and one fluorimetric assay utilizing o-aminobenzoic acid-FRK-(Dnp)P-OH were employed. The results revealed that the measurements from the different assays were not in agreement, indicating that the methods should not be used interchangeably for measurement of equine ACE activity. Rather, a single method of analysis should be adopted to achieve comparable results and critical appraisal of the literature is needed when attempting to compare results obtained from different assays
Pairing symmetry and properties of iron-based high temperature superconductors
Pairing symmetry is important to indentify the pairing mechanism. The
analysis becomes particularly timely and important for the newly discovered
iron-based multi-orbital superconductors. From group theory point of view we
classified all pairing matrices (in the orbital space) that carry irreducible
representations of the system. The quasiparticle gap falls into three
categories: full, nodal and gapless. The nodal-gap states show conventional
Volovik effect even for on-site pairing. The gapless states are odd in orbital
space, have a negative superfluid density and are therefore unstable. In
connection to experiments we proposed possible pairing states and implications
for the pairing mechanism.Comment: 4 pages, 1 table, 2 figures, polished versio
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