425 research outputs found
Multiadaptive Galerkin Methods for ODEs III: A Priori Error Estimates
The multiadaptive continuous/discontinuous Galerkin methods mcG(q) and mdG(q)
for the numerical solution of initial value problems for ordinary differential
equations are based on piecewise polynomial approximation of degree q on
partitions in time with time steps which may vary for different components of
the computed solution. In this paper, we prove general order a priori error
estimates for the mcG(q) and mdG(q) methods. To prove the error estimates, we
represent the error in terms of a discrete dual solution and the residual of an
interpolant of the exact solution. The estimates then follow from interpolation
estimates, together with stability estimates for the discrete dual solution
Investigation of rising nitrate concentrations in groundwater in the Eden Valley, Cumbria: Phase 1 project scoping study
This is the Investigation of rising nitrate concentrations in groundwater in the Eden Valley, Cumbria report produced by the Environment Agency in 2003. This report focuses on groundwater nitrate concentrations in the Eden Valley. Most boreholes in the Eden Valley had nitrate concentrations less than 20 mg/l but a significant number had higher concentrations, some exceeding the EC maximum admissible concentration for drinking water of 50 mg/l. The main objectives of this report were to investigate the causes of rising nitrate concentrations in groundwater in the Permo-Triassic sandstone aquifers of the Eden Valley area and provide sufficient understanding of the groundwater and surface water flow system, including the sources of the nitrate contamination and the processes controlling nitrate movement, so that possible management options for reversing this trend can be considered
Investigation of rising nitrate concentrations in groundwater in the Eden Valley, Cumbria. 3, saturated zone studies
This component Work Package of the Eden Valley Project was undertaken with the objective of determining the hydrogeological regime and hydrochemical stratification in selected boreholes. The subsequent aim is to apply this to better understand timescales for water movement through the saturated zone along a transect ending near to the River Eden where the Permo-Triassic sandstone aquifer is exposed or underlies thin superficial deposits.
A previous report in this series confirmed rising nitrate trends in groundwater in the study area, and suggested that with continued land use practices and with no evidence of denitrification, that this trend would continue. Another concluded that the average recharge rate is probably in the range 425-470 mm/y and the rate of water movement through the unsaturated zone is c. 3.5-3.85 m/y. Based on this estimate of water movement in the unsaturated zone, the travel time for recharge to migrate from the soil to the water table (or the delay imposed by the unsaturated zone) over most of the area where the sandstone is free of superficial deposits in the Eden Valley is c. 14 years. However if the higher fells are not considered - closer to 10 years.
Given the inherent uncertainties and limitations associated with the various methods for determining the hydrogeological regime in a boreholem, methods proposed were:
(i) to date the pore water profile within the saturated zone using CFC and SF6 tracers
(ii) to determine the variation of aquifer properties with depth, for the matrix (using laboratory techniques) and the aquifer (using field pumping techniques).
(iii) To use groundwater models to estimate groundwater travel times in the saturated zones (this part of the project has not yet been funded).
A transect approach was adopted using existing boreholes to the east of Penrith to the Eden floodplain and addressing gaps with infill drilling. Despite early promise other boreholes (on a ‘southern’ transect) were discounted due to inaccessibility or unsuitable construction. A c. 4km transect from the east of Penrith in a north-western direction to the floodplain of the River Eden was selected starting at previously drilled project borehole
4,7-Dichloroquinoline
The two molecules in the asymmetric unit of the title compound, C9H5Cl2N, are both essentially planar (r.m.s. deviations for all non-H atoms = 0.014 and 0.026 Å). There are no close C—H⋯Cl contacts
Type 1 plasminogen activator inhibitor binds to fibrin via vitronectin
Type 1 plasminogen activator inhibitor (PAI-1), the primary inhibitor of tissue-type plasminogen activator (t-PA), circulates as a complex with the abundant plasma glycoprotein, vitronectin. This interaction stabilizes the inhibitor in its active conformation. In this report, the effects of vitronectin on the interactions of PAI-1 with fibrin clots were studied. Confocal microscopic imaging of platelet-poor plasma clots reveals that essentially all fibrin-associated PAI-1 colocalizes with fibrin-bound vitronectin. Moreover, formation of platelet-poor plasma clots in the presence of polyclonal antibodies specific for vitronectin attenuated the inhibitory effects of PAI-1 on t-PA-mediated fibrinolysis. Addition of vitronectin during clot formation markedly potentiates PAI-1-mediated inhibition of lysis of 125I-labeled fibrin clots by t-PA. This effect is dependent on direct binding interactions of vitronectin with fibrin. There is no significant effect of fibrin-associated vitronectin on fibrinolysis in the absence of PAI-1. The binding of PAI-1 to fibrin clots formed in the absence of vitronectin was characterized by a low affinity (Kd ~ 3.5 μM) and rapid loss of PAI-1 inhibitory activity over time. In contrast, a high affinity and stabilization of PAI-1 activity characterized the cooperative binding of PAI- 1 to fibrin formed in the presence of vitronectin. These findings indicate that plasma PAI-1-vitronectin complexes can be localized to the surface of fibrin clots; by this localization, they may modulate fibrinolysis and clot reorganization
Tissue-specific calibration of extracellular matrix material properties by transforming growth factor-beta and Runx2 in bone is required for hearing
Publisher version: http://www.nature.com/embor/journal/v11/n10/full/embor2010135.htmlDA - 20100917 IS - 1469-3178 (Electronic) IS - 1469-221X (Linking) LA - ENG PT - JOURNAL ARTICLEDA - 20100917 IS - 1469-3178 (Electronic) IS - 1469-221X (Linking) LA - ENG PT - JOURNAL ARTICLEDA - 20100917 IS - 1469-3178 (Electronic) IS - 1469-221X (Linking) LA - ENG PT - JOURNAL ARTICLEPhysical cues, such as extracellular matrix stiffness, direct cell differentiation and support tissue-specific function. Perturbation of these cues underlies diverse pathologies, including osteoarthritis, cardiovascular disease and cancer. However, the molecular mechanisms that establish tissue-specific material properties and link them to healthy tissue function are unknown. We show that Runx2, a key lineage-specific transcription factor, regulates the material properties of bone matrix through the same transforming growth factor-beta (TGFbeta)-responsive pathway that controls osteoblast differentiation. Deregulated TGFbeta or Runx2 function compromises the distinctly hard cochlear bone matrix and causes hearing loss, as seen in human cleidocranial dysplasia. In Runx2(+/-) mice, inhibition of TGFbeta signalling rescues both the material properties of the defective matrix, and hearing. This study elucidates the unknown cause of hearing loss in cleidocranial dysplasia, and demonstrates that a molecular pathway controlling cell differentiation also defines material properties of extracellular matrix. Furthermore, our results suggest that the careful regulation of these properties is essential for healthy tissue functio
LoCuSS: Luminous infrared galaxies in the merging cluster Abell 1758 at z=0.28
We present the first galaxy evolution results from the Local Cluster
Substructure Survey (LoCuSS), a multi-wavelength survey of 100 X-ray selected
galaxy clusters at 0.15<z<0.30. LoCuSS combines far-UV through far-IR
observations of cluster galaxies with gravitational lensing analysis and X-ray
data to investigate the interplay between the hierarchical assembly of clusters
and the evolution of cluster galaxies. Here we present new panoramic
Spitzer/MIPS 24micron observations of the merging cluster Abell 1758 at z=0.279
spanning 6.5x6.5Mpc and reaching a 90% completeness limit of 400uJy. We
estimate a global cluster SFR of 910\pm320 M_sun/yr within 3 Mpc of the cluster
centre, originating from 42 galaxies with L_IR > 5x10^10 L_sun. The obscured
activity in A1758 is therefore comparable with that in Cl 0024+1654, the most
active cluster previously studied at 24um. The obscured galaxies faithfully
trace the cluster potential as revealed by the weak-lensing mass map of the
cluster, including numerous mass peaks at R~2-3Mpc that are likely associated
with infalling galaxy groups and filamentary structures. However the core
(R<500kpc) of A1758N is 2x more active in the IR than that of A1758S, likely
reflecting differences in the recent dynamical history of the two clusters. The
24micron results from A1758 therefore suggest that dust-obscured cluster
galaxies are common in merging clusters and suggests that obscured activity in
clusters is triggered by both the details of cluster-cluster mergers and
processes that operate at larger radii including those within in-falling
groups. Our ongoing far-UV through far-IR observations of a large sample of
clusters should allow us to disentangle the different physical processes
responsible for triggering obscured star formation in clusters.Comment: 13 pages, 9 figures. Accepted for publication in MNRA
Evidence of porcine and human endothelium activation by cancer-associated carbohydrates expressed on glycoproteins and tumour cells
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65560/1/jphysiol.2003.054783.pd
(E)-3-(2,6-Dichlorophenyl)-1-(4-methoxyphenyl)prop-2-en-1-one
In the title compound, C16H12Cl2O2, the dichlorophenyl and methoxyphenyl groups are linked by a prop-2-en-1-one group. The C=C double bond is trans configured. The molecule is not planar, as can be seen from the dihedral angle of 6.21 (7)° between the planes of the two rings. The crystal structure can be described by two types of crossed layers which are parallel to (110) and (10)
Are concentrations of pollutants in sharks, rays and skates (Elasmobranchii) a cause for concern? A systematic review
This review represents a comprehensive analysis on pollutants in elasmobranchs including meta-analysis on the most studied pollutants: mercury, cadmium, PCBs and DDTs, in muscle and liver tissue. Elasmobranchs are particularly vulnerable to pollutant exposure which may pose a risk to the organism as well as humans that consume elasmobranch products. The highest concentrations of pollutants were found in sharks occupying top trophic levels (Carcharhiniformes and Lamniformes). A human health risk assessment identified that children and adults consuming shark once a week are exposed to over three times more mercury than is recommended by the US EPA. This poses a risk to local fishing communities and international consumers of shark-based products, as well as those subject to the widespread mislabelling of elasmobranch products. Wider screening studies are recommended to determine the risk to elasmobranchs from emerging pollutants and more robust studies are recommended to assess the risks to human health
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