78 research outputs found

    URBAN TERRAIN CLIMATOLOGY AND REMOTE SENSING *

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    . Urban areas have been conceived of as monolithic heat islands because traditional ground observation techniques do not lend themselves to more specific analyses. Observations of urban energy-exchange obtained from calibrated electro-optical scanners combined with energy budget simulation techniques provide tools to relate the urban land use mosaic to the heat island phenomenon. Maps of surface energy-related phenomena were made from airborne scanner outputs for selected flightpaths across the city of Baltimore, Maryland. Conditions for the flight time were simulated according to the various types of land use using an energy budget simulation model which lends itself to extrapolation of simulated grid-point conditions into a map form. Maps made by simulation compare sufficiently well with those made by aerial observation to encourage further refinement of the simulation approach.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72392/1/j.1467-8306.1976.tb01110.x.pd

    Field observations of soil temperature and water tension feedback effects on needle ice nights

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    Numerous laboratory studies have indicated that thermal gradients may produce appreciable soil water movement in the absence of a strong suction field. In addition the soil water flow and thermal properties are physically interrelated. This paper presents field data taken during needle ice events at Vancouver, Canada, and yields an indication of the magnitude of interaction between the thermal and water flow properties. This feedback determines the state of soil frost hazard in a location where damage to plant material is produced by ice frost hazard in a location where damage to plant material is produced by ice needle growth. Further apparently anomalous interruption in the normal parabolic temperature-time pattern during radiation events is interpreted as the product of water flow down a thermal gradient. Zahlreiche Laboratoriumsstudien deuteten darauf hin, daß thermische Gradienten selbst bei Abwesenheit starker Saugkräfte bedeutsame Wasserbewegungen im Boden hervorrufen können. Überdies stehen die Strömung des Bodenwassers und die thermischen Eigenschaften des Bodens damit in physikalischem Zusammenhang. Die vorliegende Arbeit enthält Meßdaten, die während der Bildung von Nadeleis in Vancouver, Kanada, gewonnen wurden und größenordnungsmäßige Beziehungen zwischen Wärme- und Wasserstrom im Boden angeben. Die Rückkopplung zwischen den beiden Strömen bestimmt die Bodenfrostgefahr an Orten, wo Pflanzenschäden durch Eisnadelbildung hervorgerufen werden. Eine offensichtlich abnormale Unterbrechung des normalen Temperatur-Zeit-Verhältnisses während des Ausstrahlungsvorganges wird als Effekt der Wasserströmung entsprechend einem einem thermischen Gradienten interpretiert.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41661/1/703_2005_Article_BF02247747.pd

    The climatonomy of a needle ice event: An experiment in simulation climatology

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    Soil surface temperature, net radiation and surface heave are used to evaluate a computer simulation of a needle ice event at Vancouver, Canada. The simulation which includes fusion and soil water flow effects, provides a working example of a simulation-sensitivity experiment in climatology and therefore has implications which transcend the rather restricted subject of diurnal soil frost effects. Die Temperatur der Bodenoberfläche, die Strahlungsbilanz und die Bodenbewegung werden in einem Rechenmodell benützt, das die Eisnadelbildung in Vancouver, Kanada, simuliert. Das Modell, welches den Gefriervorgang und den Effekt der Wasserströmung im Boden einbezieht, stellt ein Beispiel eines Simulations- und Sensitivitätsexperiments in der Klimatologie dar, welches über die Belange des beschränkten Sachgebietes der Bodenfrosteffekte hinausgeht.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41665/1/704_2005_Article_BF02253559.pd

    Risk Factors Related to Inflammation and Endothelial Dysfunction in the DCCT/EDIC Cohort and Their Relationship With Nephropathy and Macrovascular Complications

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    OBJECTIVE—Because endothelial cell dysfunction and inflammation are key contributors to the development of complications in type 1 diabetes, we studied risk factors related to endothelial dysfunction and inflammation (C-reactive protein and fibrinogen, soluble vascular cell adhesion molecule-1, intracellular adhesion molecule-1, and E-selectin, and fibrinolytic markers) in a subgroup of patients from the Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Intervention and Complications (EDIC) study cohort

    Impact of diabetes duration and cardiovascular risk factors on mortality in type 2 diabetes: the Hoorn Study

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    Background. Several studies have reported differences in the mortality risk between diabetic subjects detected by screening and known diabetic patients. We studied mortality in relation to diabetes duration, and the contribution of other cardiovascular risk factors to the elevated risk. Materials and methods. Participants were type 2 diabetic subjects (n = 174) of a population-based cohort study. Of these, 95 were diagnosed by screening. Known diabetic subjects were grouped into two categories of diabetes duration, with a median duration of 2.4 and 11.2 years, respectively. We assessed the contribution of classical cardiovascular risk factors (dyslipidaemia, hypertension, and prior myocardial infarction), and of new cardiovascular risk factors (microalbuminuria, von Willebrand factor, sVCAM-1 and C-reactive protein) to the mortality risk during nearly 10 years of follow up. Cox's proportional hazards model was used to study the association of diabetes duration and mortality. Results. The age- and sex-adjusted relative risks of mortality were 2.06 (95% C.I. 1.04-4.10) and 3.19 (1.64-6.20) for the patients with short- and long-term diabetes compared with the screening-detected diabetic subjects, respectively. Adjustment for cardiovascular risk factors resulted in a reduction of mortality risk in both groups: 1.13 (0.51-2.50) and 2.39 (1.18-4.83), respectively. Mortality risk significantly increased with increasing diabetes duration, even after multiple adjustment (P-value for trend ranged from < 0.001-0.018). Conclusions. Mortality risk increased with increasing diabetes duration. In subjects with short diabetes duration the mortality risk could largely be attributed to other risk factors. In subjects with a longer diabetes duration, however, the elevated mortality risk was independent of these cardiovascular risk factors

    Characterization of anticoagulant heparinoids by immunoprofiling

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    Heparinoids are used in the clinic as anticoagulants. A specific pentasaccharide in heparinoids activates antithrombin III, resulting in inactivation of factor Xa and–when additional saccharides are present–inactivation of factor IIa. Structural and functional analysis of the heterogeneous heparinoids generally requires advanced equipment, is time consuming, and needs (extensive) sample preparation. In this study, a novel and fast method for the characterization of heparinoids is introduced based on reactivity with nine unique anti-heparin antibodies. Eight heparinoids were biochemically analyzed by electrophoresis and their reactivity with domain-specific anti-heparin antibodies was established by ELISA. Each heparinoid displayed a distinct immunoprofile matching its structural characteristics. The immunoprofile could also be linked to biological characteristics, such as the anti-Xa/anti-IIa ratio, which was reflected by reactivity of the heparinoids with antibodies HS4C3 (indicative for 3-O-sulfates) and HS4E4 (indicative for domains allowing anti-factor IIa activity). In addition, the immunoprofile could be indicative for heparinoid-induced side-effects, such as heparin-induced thrombocytopenia, as illustrated by reactivity with antibody NS4F5, which defines a very high sulfated domain. In conclusion, immunoprofiling provides a novel, fast, and simple methodology for the characterization of heparinoids, and allows high-throughput screening of (new) heparinoids for defined structural and biological characteristics

    A rockslide-generated tsunami in a Greenland fjord rang Earth for 9 days

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    Climate change is increasingly predisposing polar regions to large landslides. Tsunamigenic landslides have occurred recently in Greenland (Kalaallit Nunaat), but none have been reported from the eastern fjords. In September 2023, we detected the start of a 9-day-long, global 10.88-millihertz (92-second) monochromatic very-long-period (VLP) seismic signal, originating from East Greenland. In this study, we demonstrate how this event started with a glacial thinning–induced rock-ice avalanche of 25 × 106 cubic meters plunging into Dickson Fjord, triggering a 200-meter-high tsunami. Simulations show that the tsunami stabilized into a 7-meter-high long-duration seiche with a frequency (11.45 millihertz) and slow amplitude decay that were nearly identical to the seismic signal. An oscillating, fjord-transverse single force with a maximum amplitude of 5 × 1011 newtons reproduced the seismic amplitudes and their radiation pattern relative to the fjord, demonstrating how a seiche directly caused the 9-day-long seismic signal. Our findings highlight how climate change is causing cascading, hazardous feedbacks between the cryosphere, hydrosphere, and lithosphere.acceptedVersio
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