760 research outputs found
Molecular and behavioural evidence for gene flow between host races of the larch budmoth Zeiraphera diniana
Larch and pine associated populations of Zeiraphera diniana (Lepidoptera: Tortricidae) differ
in a number of heritable traits, but pheromone-mediated cross-attraction occurs between
them in the wild. Using a quartet mate choice design (one male and one female of each type
per cage) we estimate that, following cross-attraction by pheromones, the subsequent
probability of hybridization is approximately 28%. We also examined molecular data, and
were unable to distinguish between the races on the basis of 695bp of mitochondrial COI,
tRNA-leucine, and COII gene sequence. Both results support earlier field studies suggesting
that larch- and pine-feeding populations are host races that hybridize at an appreciable level
in the wild. The shared mitochondrial haplotypes we observed are also consistent with
ongoing and successful gene flow between the two host races
Atypical Western Mediterranean deep water formation during winter 2005
The meteorological conditions in winter 2005, with anomalously low precipitation and unusual persistency of northerlies over the NW Mediterranean, caused a large extension both in time and space of deep convection processes. As a consequence, where convection typically gives rise to the Western Intermediate Waters (WIW) a New Western Mediterranean Deep Water (N-WMDW) was produced, slightly denser (+0.01kg mâ3), warmer (+0.05ÂșC) and saltier (+0.03) than the usual WMDW. Moreover, near the continental slope, a cascading of colder and even denser water was found (-0.1ÂșC and +0.025 kg mâ3), formed over the shelf (C-WMDW). In both cases it appears the high surface salinity as a responsible for the excess of density. The origin of this higher surface salinity is discusse
Clinical Application of Sonographic Elasticity Imaging for Aging of Deep Venous Thrombosis
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135197/1/jum2003225443.pd
Diapycnal Nutrient Fluxes in the Cape Ghir upwelling region
European Geosciences Union General Assembly 22-27 April 2012, Vienna, Austria.-- 1 pageAn oceanographic survey was carried out from 18 to 29 October 2010 in the Canary Basin (PROMECA project). Near Cape Ghir, in the Northwest Africa coastal upwelling, 17 CTD casts were made to obtain continuous records of conductivity and temperature with depth, and to collect waters samples for nutrients analyses. Additionally, free-fall turbulence profiles were obtained at each station. 14 Expandable bathythermographs (XBTs) were deployed between stations to increase the grid resolution of the temperature field. Velocity data were acquired with a vessel-mounted Acoustic Doppler Current Profiler (ADCP) with a vertical bin size of 8 m. Water samples for nutrients: nitrate + nitrite (N+N), phosphates and silicates, were collected from 12 depths (down to 2000 m or the maximum depth), with 12-l Niskin bottles mounted on the rosettes sampler. The first results show low to moderate concentrations of nutrients offshore, with average values in the upper 150 m of 2.45 ± 1.98, 0.37 ± 0.18 and 1.47 ± 0.94 ΌM for N+N, phosphate and silicate, respectively. However, for stations near the Cape Ghir upwelling filament or influenced by this feature, a significant increase in the concentration of nutrients (up to 10 ”M of N+N at 200 m) was observed. We have estimated and compared the diapycnal nutrient flux in the region by using two different approaches. First, we used the dissipation rates of turbulent kinetic energy and thermal variance estimated from microstructure data acquired from turbulence profilers, and applied a model based on the dissipation ratio. This way we obtain net turbulence diffusivities in regions where there is an interaction of processes of double diffusion and turbulence induced by vertical shear of the flow. The second approach is based on obtaining diapycnal diffusivities with parameterizations of the gradient Richardson number and density ratioPeer Reviewe
Feasibility of applying ultrasound strain imaging to detect renal transplant chronic allograft nephropathy
Feasibility of applying ultrasound strain imaging to detect renal transplant chronic allograft nephropathy.Chronic renal transplant fibrosis, often termed Chronic Allograft Nephropathy, may progress undetected. Since renal fibrosis may be accompanied by a change in measurable elastic tissue properties, ultrasound strain measurements may be useful in its detection. Ultrasound strain imaging was performed for two subjects with renal transplants; one with normal renal function and one with mild renal insufficiency and biopsy demonstrated fibrosis. Subjects underwent ultrasound examination with application of a controlled deformation using phase-sensitive, two-dimensional speckle tracking to evaluate internal tissue motion to measure tissue displacement and strain. Measurements over multiple beams for an equivalent deformational stress showed there was a threefold differences in renal cortical strain between the two subjects. These data suggest that ultrasound elasticity imaging may prove useful in measuring mechanical changes related to fibrosis within the transplant kidney
Dissolved Organic Matter (DOM) in the open Mediterranean Sea. I. Basin-Wide distribution and drivers of chromophoric DOM
Original research articleChromophoric dissolved organic matter (CDOM) in the open Mediterranean Sea (MedSea) is barely documented, remaining the basinâwide patterns in intermediate and deep waters still enigmatic. Here, fullâdepth distributions of CDOM absorption coefficients and spectral slopes recorded during the HOTMIX 2014 cruise are presented and their respective environmental drivers resolved. General Additive Models (GAMs) in surface waters and Optimum MultiParameter (OMP) water mass analysis in deep waters were applied. In the surface, apparent oxygen utilisation (AOU), a proxy to cumulative net community respiration, explained most of the variability of dissolved organic carbon (DOC) and the absorption coefficient at 254âŻnm (a254), whereas the absorption coefficient at 325âŻnm (a325), and the spectral slopes were mostly explained by potential temperature, a proxy to stratification and solar radiation, indicating that both water column stability and photobleaching may drive the variability of the UVâA absorbing CDOM components. In deep waters, the effect of water mass mixing and basinâscale mineralization were discerned from local mineralization processes. Water mass mixing and basinâscale mineralization contributed more substantially to explain the variability of DOC, a254 and a325 (82â91%) than the variability of the spectral slopes (35â64%). Local mineralization processes indicate that DOC and CDOM play a more relevant role in the carbon cycle in the Eastern (EastMed) than in the Western (WestMed) Mediterranean: whereas DOC contributed to 66âŻÂ±âŻ10% of the oxygen demand in the EastMed, it represented only 24âŻÂ±âŻ4% in the WestMed. Independently of basins and layers, a254 revealed as an excellent proxy to the concentration of DOC in the MedSea. Also, the unexpected inverse relationship of a325 with AOU indicates that the consumption of the UVâA absorbing CDOM fraction prevails over their productionSpanish Ministry of Education and Culture, Spanish Ministry of Economy and Competitiviness, FEDER, CSIC, University of GranadaVersiĂłn del editor3,26
Model-Based Reconstructive Elasticity Imaging Using Ultrasound
Elasticity imaging is a reconstructive imaging technique where tissue motion in response to mechanical excitation is measured using modern imaging systems, and the estimated displacements are then used to reconstruct the spatial distribution of Young's modulus. Here we present an ultrasound elasticity imaging method that utilizes the model-based technique for Young's modulus reconstruction. Based on the geometry of the imaged object, only one axial component of the strain tensor is used. The numerical implementation of the method is highly efficient because the reconstruction is based on an analytic solution of the forward elastic problem. The model-based approach is illustrated using two potential clinical applications: differentiation of liver hemangioma and staging of deep venous thrombosis. Overall, these studies demonstrate that model-based reconstructive elasticity imaging can be used in applications where the geometry of the object and the surrounding tissue is somewhat known and certain assumptions about the pathology can be made
Sonographic Elasticity Imaging of Acute and Chronic Deep Venous Thrombosis in Humans
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135317/1/jum20062591179.pd
Dissolved organic matter (DOM) in the open Mediterranean Sea. II: Basin-wide distribution and drivers of fluorescent DOM
Research articleFluorescent dissolved organic matter (FDOM) in the Mediterranean Sea was analysed by excitationâemission matrix (EEM) spectroscopy and parallel factor (PARAFAC) analysis during the cruise HOTMIX 2014. A 4âcomponent model, including 3 humicâlike and 1 proteinâlike compounds, was obtained. To decipher the environmental factors that dictate the distributions of these components, we run generalized additive models (GAMs) in the epipelagic layer and an optimum multiparametric (OMP) water masses analysis in the mesoâ and bathypelagic layers. In the epipelagic layer, apparent oxygen utilization (AOU) and temperature presented the most significant effects on the variability of the marine humic-like peak M fluorescence, suggesting that its distribution was controlled by the net community respiration of organic matter and photobleaching. On the contrary, the variability of the soil humic-like peak E and the proteinâlike peak T fluorescence was explained mainly by the prokaryotic heterotrophic abundance, which decreased eastwards. In the mesoâ and bathypelagic layers, water mass mixing and basinâscale mineralization processes explained >72% and 63% of the humicâlike and proteinâlike fluorescence variability, respectively. When analysing the two basins separately, the OMP model offered a better explanation of the distribution of fluorescence in the eastern Mediterranean Sea, as expected from the reduced biological activity in this ultraâoligotrophic basin. Furthermore, while western Mediterranean deep waters display the usual trend in the global ocean (increase of humicâlike fluorescence and decrease of proteinâlike fluorescence with higher AOU values), the eastern Mediterranean deep waters presented an opposite trend. Different initial fluorescence intensities of the water masses that mix in the eastern basin, with Adriatic and Aegean origins, seem to be behind this contrasting pattern. The analysis of the transectâscale mineralization processes corroborate this hypothesis, suggesting a production of humicâlike and a consumption of proteinâlike fluorescence in parallel with water mass ageing. Remarkably, the transectâscale variability of the chromophoric dissolved organic matter (CDOM) absorbing at the excitation wavelength of the humicâlike peak M indicates an unexpected loss with increasing AOU, which suggests that the consumption of the nonâfluorescent fraction of CDOM absorbing at that wavelength exceeded the production of the fluorescent fraction observed hereProject HOTMIX (reference CTM2011â30010âC02 01âMAR and 02âMAR), coâfinanced with FEDER funds (re ference BESâ2012â056175) ; the project MODMED from CSIC (PIE, 201730E020) and the project FERMIO (MINECO, CTM2014â57334âJIN), coâfinanced with FEDER fundsVersiĂłn del editor3,26
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