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Search Results: 1 - 10 of 461904 matches for " A. Mikkelsen "
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Dime dónde vives y sabré por qué llegaste. Movilidad territorial y poblamiento de localidades peque?as del partido de General Pueyrredon (Buenos Aires)
Ares, Sofía Estela;Mikkelsen, Claudia Andrea;
Investigaciones geográficas , 2010,
Abstract: recognizing the space transformations related to the residential behaviors and the mobility of the population requires taking into consideration all the mobility habits, whatever the distance and duration. the purpose of this work is to put into evidence the prevailing motivations in the processes of observed mobility of the population in a set of minor cities next to provincial routes 11th south and 226th of general pueyrredon district (buenos aires province). primary data were collected through ninety eight semi-structured surveys carried out in the space units that comprise the study area. the selection of the sampling units was accomplished through a non probabilistic method. the results show a set of non similarities among distinctive settlement lines, and even within them, and point to processes of consolidation of the social-territorial fragmentation beyond the main district urban area.
Dime dónde vives y sabré por qué llegaste. Movilidad territorial y poblamiento de localidades peque as del partido de General Pueyrredon (Buenos Aires)
Sofía Estela Ares,Claudia Andrea Mikkelsen
Investigaciones geográficas , 2010,
Abstract: Reconocer las transformaciones espaciales relacionadas con los comportamientos residenciales y la movilidad de la población, requiere tomar en consideración el conjunto de formas de movilidad, cualquiera sea la distancia y duración. El propósito de este trabajo es poner en evidencia las motivaciones intervinientes en los procesos de movilidad de la población observadas en un conjunto de localidades menores próximas a las rutas provinciales 11 sur y 226 del Partido de General Pueyrredon (Buenos Aires). Los datos primarios fueron obtenidos a través de la realización de noventa y ocho encuestas semi-estructuradas relevadas en las unidades espaciales que conforman el área en estudio. La selección de las unidades de muestreo se llevó a cabo a través de un método aleatorio, no probabilístico. Los resultados muestran un conjunto de disimilitudes entre los ejes de poblamiento y aun al interior de éstos, y se alan procesos de consolidación de la fragmentación socio-territorial más allá del aglomerado principal del distrito.
Large surface meltwater discharge from the Kangerlussuaq sector of the Greenland ice sheet during the record-warm year 2010 explained by detailed energy balance observations
D. van As,A. L. Hubbard,B. Hasholt,A. B. Mikkelsen
The Cryosphere , 2012, DOI: 10.5194/tc-6-199-2012
Abstract: This study uses data from six on-ice weather stations, calibrated MODIS-derived albedo and proglacial river gauging measurements to drive and validate an energy balance model. We aim to quantify the record-setting positive temperature anomaly in 2010 and its effect on mass balance and runoff from the Kangerlussuaq sector of the Greenland ice sheet. In 2010, the average temperature was 4.9 °C (2.7 standard deviations) above the 1974–2010 average in Kangerlussuaq. High temperatures were also observed over the ice sheet, with the magnitude of the positive anomaly increasing with altitude, particularly in August. Simultaneously, surface albedo was anomalously low in 2010, predominantly in the upper ablation zone. The low albedo was caused by high ablation, which in turn profited from high temperatures and low winter snowfall. Surface energy balance calculations show that the largest melt excess (~170%) occurred in the upper ablation zone (above 1000 m), where higher temperatures and lower albedo contributed equally to the melt anomaly. At lower elevations the melt excess can be attributed to high atmospheric temperatures alone. In total, we calculate that 6.6 ± 1.0 km3 of surface meltwater ran off the ice sheet in the Kangerlussuaq catchment in 2010, exceeding the reference year 2009 (based on atmospheric temperature measurements) by ~150%. During future warm episodes we can expect a melt response of at least the same magnitude, unless a larger wintertime snow accumulation delays and moderates the melt-albedo feedback. Due to the hypsometry of the ice sheet, yielding an increasing surface area with elevation, meltwater runoff will be further amplified by increases in melt forcings such as atmospheric heat.
Surface mass budget and meltwater discharge from the Kangerlussuaq sector of the Greenland ice sheet during record-warm year 2010
D. van As,A. Hubbard,B. Hasholt,A. B. Mikkelsen
The Cryosphere Discussions , 2011, DOI: 10.5194/tcd-5-2319-2011
Abstract: The year 2010 has been anomalously warm in most of Greenland, most notably in the south and along the western coast. Our study targets the Kangerlussuaq region around 67° N in Southwest Greenland, where the temperature anomalies were record setting. In 2010, the average temperature was 5 °C (2.7 standard deviations) above the 1974–2010 average in the town of Kangerlussuaq. High temperatures were also observed over the ice sheet, with the positive anomaly increasing with altitude. Also surface albedo, from calibrated MODIS measurements, was anomalously low in 2010, chiefly in the upper ablation zone. The low albedo was caused by the high ablation in 2010, which profited in turn from high temperatures, low albedo, and of low wintertime accumulation. The largest melt excess (166%) was found in the upper ablation zone, where higher temperatures and lower albedo contributed equally to the melt anomaly. In total, we estimate that 6.6 km3 of surface meltwater ran off the ice sheet in the Kangerlussuaq catchment area in 2010, exceeding "normal" year 2009 by 145%. When compared to discharge estimated from discharge measurements in the proglacial river we find good agreement. The time lag between the records is caused by storage within and underneath the ice sheet, and suggests adaption of the subglacial drainage system to meltwater availability, with more efficient drainage occurring after the peak of the melt season.
Review of Survey activities 2011: Methane and possible gas hydrates in the Disko Bugt region, central West Greenland
Mikkelsen, N.,Laier, T.,Nielsen, T.,Kuijpers, A.
Geological Survey of Denmark and Greenland Bulletin , 2012,
The Influence of an Exogenous Microbial Enzyme Supplement on Feed Consumption, Body Growth and Follicular Development of Pre-Lay Pullets on Maize-Soy Diets
N. Chauynarong,P.A. Iji,S. Isariyodom,L. Mikkelsen
International Journal of Poultry Science , 2008,
Abstract: An experiment was conducted to examine the benefits of supplementing maize-soy diets with a composite microbial enzyme, Allzyme SSF, for laying hens at the pullet stage. Seven hundred and twenty 12-week old Isa Brown pullets were used in the different level of protein content diets. Feed intake from 12 to 16 weeks of age was unaffected by the enzyme supplement, except at the lowest protein content (P<0.05). Feed intake was, however, affected by the enzyme supplement between 16 and 20 weeks (P<0.001) and over the entire trial period (P<0.05). Body weight at 16 weeks of age was reduced (P<0.05) on the control low-protein diet. Feed conversion ratio was not affected by dietary protein content or through supplementation with the microbial enzyme. The relative weight of the ovary was reduced (P<0.01) on the low protein control diet, but the weight of visceral organs associated with digestion was not affected. The pullets in all groups failed to come into lay at 17 weeks of age, mainly due to very severe winter, as the experiment was conducted in a house that was not completely temperature-controlled. Onset of lay occurred from about 23 weeks of age, after the hens were already on a commercial diet but effects of previous dietary treatments on early egg production were noticeable.
Comparing linear ion-temperature-gradient-driven mode stability of the National Compact Stellarator Experiment and a shaped tokamak
J. A. Baumgaertel,G. W. Hammett,D. R. Mikkelsen
Physics , 2012, DOI: 10.1063/1.4791657
Abstract: One metric for comparing confinement properties of different magnetic fusion energy configurations is the linear critical gradient of drift wave modes. The critical gradient scale length determines the ratio of the core to pedestal temperature when a plasma is limited to marginal stability in the plasma core. The gyrokinetic turbulence code GS2 was used to calculate critical temperature gradients for the linear, collisionless ion temperature gradient (ITG) mode in the National Compact Stellarator Experiment (NCSX) and a prototypical shaped tokamak, based on the profiles of a JET H-mode shot and the stronger shaping of ARIES-AT. While a concern was that the narrow cross section of NCSX at some toroidal locations would result in steep gradients that drive instabilities more easily, it is found that other stabilizing effects of the stellarator configuration offset this so that the normalized critical gradients for NCSX are competitive with or even better than for the tokamak. For the adiabatic ITG mode, NCSX and the tokamak had similar critical gradients, though beyond marginal stability, NCSX had larger growth rates. However, for the kinetic ITG mode, NCSX had a higher critical gradient and lower growth rates until a/L_T is approximately 1.5 times a/L_{T,crit}, when it surpassed the tokamak's. A discussion of the results presented with respect to a/L_T vs. R/L_T is included.
The Effect of Glucose Added to the Dialysis Fluid on Blood Pressure, Vasoactive Hormones and Energy Transfer during Hemodialysis in Chronic Renal Failure  [PDF]
Erling B. Pedersen, Birte Ardal, Jesper N. Bech, Thomas G. Lauridsen, Niels A. Larsen, Lisbeth Mikkelsen, Maren Sangill, Ingrid M. Thomsen
Open Journal of Nephrology (OJNeph) , 2011, DOI: 10.4236/ojneph.2011.12002
Abstract: Background: Previous studies showed that blood pressure was reduced in patients with chronic renal failure during hemodialysis with glucose added to the dialysis fluid. We wanted to test the hypotheses that blood pressure is reduced in non-diabetic and diabetic dialysis patients, when glucose is added to the dialysis fluid, and that blood pressure changes are caused by changes in plasma concentrations of vasoactive hormones or to vasodilation secondary to an increase in body temperature. Methods: The effect of dialysis with glucose added to the dialysis fluid was measured in three randomized, placebo-controlled, un-blinded and cross-over studies with periods of one week duration. In non-diabetic nephropathy (Study 1, n = 19) and diabetic nephropathy (Study 2, n = 15), we measured blood pressure (BP) and pulse rate (PR), plasma concentrations of glucose (p-Glucose), renin (PRC), angiotensin II (p-AngII), endothelin (p-Endot), insulin (p-Ins), glucagon (p-Glu), and human growth hormone (p-hGH). In non-diabetic nephropathy (Study 3, n = 24), we measured the effect of dialysis with glucose added to the dialysis fluid on energy transport from form the body using body temperature control. Results: Study 1 and 2 showed that BP, PRC, p-AngII, and p-Ins were unchanged, whereas P-Endot increased and P-hGH decreased, in dialysis patients with or without glucose added to the dialysis fluid. In diabetics, a marginal increase in p-Glu was measured during dialysis with glucose, but not without glucose. Study 3 showed that SBP increased significantly using dialysis with temperature control of dialysis fluid compared with no temperature control (145 versus 138 mm Hg). In parallel with the increase in SBP, the energy flux from the patients was significantly higher with temperature control than without. Conclusion: In non-diabetics and diabetics, blood pressure was unchanged during dialysis with glucose added to the dialysis fluid in a short-term study. Vasoactive hormones in plasma were changed in the same way independently of glucose in the dialysis fluid. Systolic blood pressure increased using dialysis with temperature control of dialysis fluid, presumably due to vasoconstriction to prevent or antagonize a fall in body temperature.
Atmospheric boundary layer wind profile at a flat coastal site – wind speed lidar measurements and mesoscale modeling results
R. Floors, E. Batchvarova, S.-E. Gryning, A. N. Hahmann, A. Pe a,T. Mikkelsen
Advances in Science and Research (ASR) , 2011, DOI: 10.5194/asr-6-155-2011
Abstract: Wind profiles up to 600 m height are investigated. Measurements of mean wind speed profiles were obtained from a novel wind lidar and compared to model simulations from a mesoscale model (WRF-ARW v3.1). It is found that WRF is able to predict the mean wind profile rather well and typically within 1–2 m s 1 to the individual measured values. WRF underpredicts the normalized wind profile, especially for stable conditions. The effect of baroclinicity on the upper part of the wind profile is discussed.
Partial Regulatory T Cell Depletion Prior to Acute Feline Immunodeficiency Virus Infection Does Not Alter Disease Pathogenesis
S. Rochelle Mikkelsen,Julie M. Long,Lin Zhang,Erin R. Galemore,Sue VandeWoude,Gregg A. Dean
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017183
Abstract: Feline immunodeficiency virus (FIV) infection in cats follows a disease course similar to HIV-1, including a short acute phase characterized by high viremia, and a prolonged asymptomatic phase characterized by low viremia and generalized immune dysfunction. CD4+CD25hiFoxP3+ immunosuppressive regulatory T (Treg) cells have been implicated as a possible cause of immune dysfunction during FIV and HIV-1 infection, as they are capable of modulating virus-specific and inflammatory immune responses. Additionally, the immunosuppressive capacity of feline Treg cells has been shown to be increased during FIV infection. We have previously shown that transient in vivo Treg cell depletion during asymptomatic FIV infection reveals FIV-specific immune responses suppressed by Treg cells. In this study, we sought to determine the immunological influence of Treg cells during acute FIV infection. We asked whether Treg cell depletion prior to infection with the highly pathogenic molecular clone FIV-C36 in cats could alter FIV pathogenesis. We report here that partial Treg cell depletion prior to FIV infection does not significantly change provirus, viremia, or CD4+ T cell levels in blood and lymphoid tissues during the acute phase of disease. The effects of anti-CD25 mAb treatment are truncated in cats acutely infected with FIV-C36 as compared to chronically infected cats or FIV-na?ve cats, as Treg cell levels were heightened in all treatment groups included in the study within two weeks post-FIV infection. Our findings suggest that the influence of Treg cell suppression during FIV pathogenesis is most prominent after Treg cells are activated in the environment of established FIV infection.
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