2,194 research outputs found
Studies of ecomorphological variations of the European hare (Lepus europaeus) in Turkey
Hares (Lepus spp.) are widely distributed across the globe and are adapted to diverse climatic conditions. In order to study the ecomorphological variations of hares from Turkey, the body and cranial measurements and body weight, as well as coat color types, of 138 hares collected from all over Turkey between 2006 and 2012, were examined. Statistically significant differences between regional samples (p <0.05, ANOVA) only in terms of body weight and hindfoot length were found; however, there were a good number of external phenotypes, particularly in terms of coat color variants of the hare specimens. Furthermore, populations had similar variations in terms of morphometric measurement, body weight and coat coloration between different geographical regions. Turkish hares did not exhibit clinal variations from south to north in body and cranial measurements depending on the mean annual temperatures and precipitation. Therefore, it was assumed that all of these variations might be a polymorphism related to the local adaptations and high level of admixture of gene pools in Anatolia
Near-field flow structure of a confined wall jet on flat and concave rough walls
Experimental results are presented of the mean flow and turbulence characteristics in the near field of a plane wall jet issuing from a nozzle onto flat and concave walls consisting of fixed sand beds. This is a flow configuration of interest for sediment erosion, also referred to as scouring. The measurements were made with an acoustic profiler that gives access to the three components of the instantaneous velocities. For the flat-wall flow, it is shown that the outer-layer spatial growth rate and the maxima of the Reynolds stresses approach the values accepted for the far field of a wall jet at a downstream distance x/b0 ≈ 8. These maxima are only about half the values of a plane free jet. This reduction in Reynolds stresses is also observed in the shear-layer region, x/b0 11, the maximum Reynolds shear stress approaches the value of a plane free jet. This change in Reynolds stresses is related to the mean vertical velocity that is negative for x/b0 < 8 and positive further downstream. The evolution of the inner region of the wall jet is found to be in good agreement with a previous model that explicitly includes the roughness length. On the concave wall, the mean flow and the Reynolds stresses are drastically changed by the adverse pressure gradient and especially by the development of Görtler vortices. On the downslope side of the scour hole, the flow is nearly separating with the wall shear stress tending to zero, whereas on the upslope side, the wall-friction coefficient is increased by a factor of about two by Görtler vortices. These vortices extend well into the outer layer and, just above the wall, cause a substantial increase in Reynolds shear stres
Interactions between aquatic plants and turbulent flow : A field study using stereoscopic PIV
Peer reviewedPostprin
Effective kernel mapping for OpenCL applications in heterogeneous platforms
Many core accelerators are being deployed in many systems to improve the processing capabilities. In such systems, application mapping need to be enhanced to maximize the utilization of the underlying architecture. Especially in GPUs mapping becomes critical for multi-kernel applications as kernels may exhibit different characteristics. While some of the kernels run faster on GPU, others may refer to stay in CPU due to the high data transfer overhead. Thus, heterogeneous execution may yield to improved performance compared to executing the application only on CPU or only on GPU. In this paper, we propose a novel profiling-based kernel mapping algorithm to assign each kernel of an application to the proper device to improve the overall performance of an application. We use profiling information of kernels on different devices and generate a map that identifies which kernel should run on where to improve the overall performance of an application. Initial experiments show that our approach can effectively map kernels on CPU and GPU, and outperforms to a CPU-only and GPU-only approach. © 2012 IEEE
Near-field flow structure of a confined wall jet on flat and concave rough walls
Experimental results are presented of the mean flow and turbulence characteristics in the near field of a plane wall jet issuing from a nozzle onto flat and concave walls consisting of fixed sand beds. This is a flow configuration of interest for sediment erosion, also referred to as scouring. The measurements were made with an acoustic profiler that gives access to the three components of the instantaneous velocities. For the flat-wall flow, it is shown that the outer-layer spatial growth rate and the maxima of the Reynolds stresses approach the values accepted for the far field of a wall jet at a downstream distance . These maxima are only about half the values of a plane free jet. This reduction in Reynolds stresses is also observed in the shear-layer region, , the maximum Reynolds shear stress approaches the value of a plane free jet. This change in Reynolds stresses is related to the mean vertical velocity that is negative for and positive further downstream. The evolution of the inner region of the wall jet is found to be in good agreement with a previous model that explicitly includes the roughness length.On the concave wall, the mean flow and the Reynolds stresses are drastically changed by the adverse pressure gradient and especially by the development of Görtler vortices. On the downslope side of the scour hole, the flow is nearly separating with the wall shear stress tending to zero, whereas on the upslope side, the wall-friction coefficient is increased by a factor of about two by Görtler vortices. These vortices extend well into the outer layer and, just above the wall, cause a substantial increase in Reynolds shear stress
Marked overlap of four genetic syndromes with dyskeratosis congenita confounds clinical diagnosis
Financial support provided by The Medical Research Council-MR/K000292/1, Children with Cancer- 2013/144 and Blood Wise-14032 (AJW, LC, SC, AE, TV, HT and ID). KMG is supported by the National Institute for Health Research through the NIHR Southampton Biomedical Research Centre
Exact results of the mixed-spin Ising model on a decorated square lattice with two different decorating spins of integer magnitudes
The mixed-spin Ising model on a decorated square lattice with two different
decorating spins of the integer magnitudes S_B = 1 and S_C = 2 placed on
horizontal and vertical bonds of the lattice, respectively, is examined within
an exact analytical approach based on the generalized decoration-iteration
mapping transformation. Besides the ground-state analysis, finite-temperature
properties of the system are also investigated in detail. The most interesting
numerical result to emerge from our study relates to a striking critical
behaviour of the spontaneously ordered 'quasi-1D' spin system. It was found
that this quite remarkable spontaneous order arises when one sub-lattice of the
decorating spins (either S_B or S_C) tends towards their 'non-magnetic' spin
state S = 0 and the system becomes disordered only upon further single-ion
anisotropy strengthening. The effect of single-ion anisotropy upon the
temperature dependence of the total and sub-lattice magnetization is also
particularly investigated.Comment: 17 pages, 6 figure
Dynamic drag modeling of submerged aquatic vegetation canopy flows
Vegetation has a profound effect on flow and sediment transport
processes in natural rivers, by increasing both skin friction and form
drag. The increase in drag introduces a drag discontinuity between the
in-canopy flow and the flow above, which leads to the development of an
inflection point in the velocity profile, resembling a free shear layer.
Therefore, drag acts as the primary driver for the entire canopy system.
Most current numerical hydraulic models which incorporate vegetation
rely either on simple, static plant forms, or canopy-scaled drag terms.
However, it is suggested that these are insufficient as vegetation
canopies represent complex, dynamic, porous blockages within the flow,
which are subject to spatially and temporally dynamic drag forces. Here
we present a dynamic drag methodology within a CFD framework.
Preliminary results for a benchmark cylinder case highlight the accuracy
of the method, and suggest its applicability to more complex cases
Influence of steps on the tilting and adsorption dynamics of ordered Pn films on vicinal Ag(111) surfaces
Here we present a structural study of pentacene (Pn) thin films on vicinal
Ag(111) surfaces by He atom diffraction measurements and density functional
theory (DFT) calculations supplemented with van der Waals (vdW) interactions.
Our He atom diffraction results suggest initial adsorption at the step edges
evidenced by initial slow specular reflection intensity decay rate as a
function of Pn deposition time. In parallel with the experimental findings, our
DFT+vdW calculations predict the step edges as the most stable adsorption site
on the surface. An isolated molecule adsorbs as tilted on the step edge with a
binding energy of 1.4 eV. In addition, a complete monolayer (ML) with
pentacenes flat on the terraces and tilted only at the step edges is found to
be more stable than one with all lying flat or tilted molecules, which in turn
influences multilayers. Hence our results suggest that step edges can trap Pn
molecules and act as nucleation sites for the growth of ordered thin films with
a crystal structure similar to that of bulk Pn.Comment: 4 pages, 4 figures, 1 tabl
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