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Search Results: 1 - 10 of 585708 matches for " A. N. Hahmann "
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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.
Toward a climate downscaling for the Eastern Mediterranean at high-resolution
A. N. Hahmann, D. Rostkier-Edelstein, T. T. Warner, Y. Liu, F. Vandenberghe,S. P. Swerdlin
Advances in Geosciences (ADGEO) , 2007,
Abstract: As a first step toward downscaling global model simulations of future climates for the eastern Mediterranean Sea and surrounding land area, mesoscale-model simulations with the Pennsylvania State University – National Center for Atmospheric Research (NCAR) mesoscale model, version 5 (MM5) are verified in the context of precipitation amount. The simulations are driven with January NCAR-NCEP reanalysis project (NNRP) lateral-boundary conditions and assimilate surface and upper air observations. The results of the simulations compare reasonably well with rain gauge and satellite estimates of monthly total precipitation, and the model reproduces the overall trends in inter-annual precipitation variability for one test region. Cyclones during the period were tracked, and their properties identified.
Development and first assessment of a questionnaire for health care utilization and costs for cardiac patients
Bernd Schweikert, Harry Hahmann, Reiner Leidl
BMC Health Services Research , 2008, DOI: 10.1186/1472-6963-8-187
Abstract: To design the questionnaire, the literature was searched for contributions to the assessment of utilization of health care resources by patient-administered questionnaires. Based on these findings, we developed a retrospective questionnaire appropriate for the measurement of disease-related costs over a period of 3 months in ACE patients. Items were generated by reviewing existing guidelines and by interviewing medical specialists and patients. In this study, the questionnaire was tested on 106 patients, aging 35–65 who were admitted for rehabilitation after ACE. It was compared with prospectively measured data; selected items were compared with administrative data from sickness funds.The questionnaire was accepted well (response rate = 88%), and respondents completed the questionnaire in an average time of 27 minutes. Concordance between retrospective and prospective data showed an intraclass correlation (ICC) ranging between 0.57 (cost of medical intake) and 0.9 (hospital days) with the other main items (physician visits, days off work, medication) clustering around 0.7. Comparison between self-reported and administrative data for days off work and hospitalized days were possible for n = 48. Respective ICCs ranged between 0.92 and 0.94, although differences in mean levels were observed.The questionnaire was accepted favorably and correlated well with alternative measurement approaches. This first assessment showed promising characteristics of this questionnaire in different aspects of validity for patients with ACE. However, additional research and more extensive tests in other patient groups would be worthwhile.The valid and reliable measurement of health service utilization, productivity losses and consequently total disease-related costs is a prerequisite for health economic analysis. While health effects can be measured by numerous generic and disease-specific instruments [1-3], much less work has been done regarding standardized methods to measure health care
Measuring Completeness of Building Footprints in OpenStreetMap over Space and Time
Robert Hecht,Carola Kunze,Stefan Hahmann
ISPRS International Journal of Geo-Information , 2013, DOI: 10.3390/ijgi2041066
Abstract: Due to financial or administrative constraints, access to official spatial base data is currently limited to a small subset of all potential users in the field of spatial planning and research. This increases the usefulness of Volunteered Geographic Information (VGI), in particular OpenStreetMap (OSM), as supplementary datasets or, in some cases, alternative sources of primary data. In contrast to the OSM street network, which has already been thoroughly investigated and found to be practically complete in many areas, the degree of completeness of OSM data on buildings is still unclear. In this paper we describe methods to analyze building completeness and apply these to various test areas in Germany. Official data from national mapping and cadastral agencies is used as a basis for comparison. The results show that unit-based completeness measurements (e.g., total number or area of buildings) are highly sensitive to disparities in modeling between official data and VGI. Therefore, we recommend object-based methods to study the completeness of OSM building footprint data. An analysis from November 2011 in Germany indicated a completeness of 25% in the federal states of North Rhine-Westphalia and 15% in Saxony. Although further analyses from 2012 confirm that data completeness in Saxony has risen to 23%, the rate of new data input was slowing in the year 2012.
"CITY 2020+": assessing climate change impacts for the city of Aachen related to demographic change and health – a progress report
C. Schneider, C. Balzer, M. Buttst dt, K. E er, S. Ginski, J. Hahmann, G. Ketzler, M. Klemme, A. Kr pelin, H. Merbitz, S. Michael, T. Sachsen, A. Siuda, M. Weishoff-Houben, M. F. Brunk, W. Dott, H. Hofmeister, C. Pfaffenbach, C. Roll,K. Selle
Advances in Science and Research (ASR) , 2011, DOI: 10.5194/asr-6-261-2011
Abstract: The research initiative CITY 2020+ assesses the risks and opportunities for residents in urban built environments under projected demographic and climate change for the year 2020 and beyond, using the city of Aachen as a case study. CITY 2020+ develops strategies, options and tools for planning and developing sustainable future city structures. The investigation focuses on how urban environment, political structure and residential behaviour can best be adapted, with attention to the interactions among structural, political, and sociological configurations and their impacts on human health. The interdisciplinary research is organized in three clusters. Within the first cluster, strategies of older people exposed to heat stress, and their networks as well as environmental health risks according to atmospheric conditions are examined. The second cluster addresses governance questions, urban planning and building technologies as well as spatial patterns of the urban heat island. The third cluster includes studies on air quality related to particulate matter and a historical perspective of city development concerning environmental issues and climate variability. However, it turns out that research topics that require an interdisciplinary approach are best addressed not by pre-structuring the work into related sub-projects but through combining them according to shared methodological approaches. Examples illustrating this rather practical approach within ongoing research are presented in this paper.
Age-Dependency of Clinical Characteristics of Patients Participating Cardiovascular Rehabilitation Results from the German  [PDF]
Roland Nebel, Michael Marx, Michael Geier, Brigitte Buran-Kilian, Taoufik Ouarrak, Manju Guha, Gregor Sauer, Gerd B?nner, Harry Hahmann, Ralf Jordan, Michaela Julia Engelhard, Bernhard Rauch, Birna Bjarnason-Wehrens
Open Journal of Therapy and Rehabilitation (OJTR) , 2014, DOI: 10.4236/ojtr.2014.24026
Abstract: Background: Cardiovascular rehabilitation in Germany traditionally is offered as inpatient service often located far from patient’s residence, and ambulatory rehabilitation still represents a minority. The German Registry of Ambulatory Cardiac Rehabilitation (KARREE) was designed to contribute to rehabilitation quality assurance and to evaluate clinical characteristics of patients participating in ambulatory rehabilitation centers. Methods: In four ambulatory rehabilitation centers 2989 patients were consecutively registered from 2008 to 2011 and evaluated with respect to social status, cardiovascular diagnoses and risk factors, psychological status, medication and short term clinical and social outcome. Results: Most patients referred to the ambulatory cardiac rehabilitation had an acute cardiovascular event, with patients after acute coronary syndrome representing the majority (59.9%). Female were strongly underrepresented (16.7%). Patient’s clinical characteristics varied with the age groups evaluated (<50 years, 50 - 70 years, > 70 years). Whereas the reported physical inactivity, overweight and cigarette smoking was declining with age, diabetes and hypertension significantly increased. Furthermore the reported and evaluated psychosocial stress was declining with age. Regarding the group of patients still employed, 43.5 % were estimated as fit for work directly at the end of the rehabilitation program, whereas a stepwise reintegration into employment was performed in 16.7%. The majority of patients were transferred to ambulatory heart groups or other forms of after care for stabilizing regular physical activity. Conclusions: The large variation of the characteristics of patients participating cardiac rehabilitation underscore the need of an individualized approach for a successful implementation of secondary prevention and reintegration of these patients into their social life.
Dynamic Changes in Lipid Peroxidation and Antioxidant Level in Rat’s Tissues with Macrovipera lebetina obtusa and Montivipera raddei Venom Intoxication  [PDF]
N. A. Zaqaryan, N. A. Ghazaryan, N. M. Ayvazyan
Journal of Biophysical Chemistry (JBPC) , 2014, DOI: 10.4236/jbpc.2014.54017
Abstract: We investigated the balance of free radicals in different tissues (liver, heart, brain and muscle) of rats in course of in vivo and in vitro processing by Macrovipera lebetina obtusa (MLO) and Montivipera raddei (MR) snake venoms. Chemiluminescence (ChL) levels were examined in tissue assays after incubation (at 37 °C for a period of 10 min) with venom for in vitro experiments and in tissue assays isolated of 10 min after venom injection for in vivo experiments. The TBA-test was also performed to confirm the free radical expression. The activities of antioxidant enzymes (such as superoxide dismutase and glutathione peroxidase) in isolated tissues were detected by spectro-photometry. During the in vitro processing chemiluminescence levels of tissue homogenates significantly decreased, while in course of in vivo intoxication the level of ChL was elevated in brain and liver; lipid peroxidation also increased in brain tissue, but there was no significant balance change in other tissues; the activity of superoxide dismutase mainly correlated with changes of free radical balance during intoxication. On the contrary, the activity of glutathione peroxidase showed the reverse tendencies to change. We suggest that free radicals and their oxidative stresses may play a role in the early stage of intoxication causing the so-named “spreading-effect”, which is very characteristic for the venom of vipers.
Review of the Book “Causality and Reversibility in Irreversible Time”  [PDF]
A. N. Morozov
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.33029
Abstract: The book concerns a number of the most fundamental concepts and problems of modern physics: causality, entanglement and the nature of time. A distinguishing feature of author’s approach is equal attention to both the theoretical and experimental challenges posed by those issues. From very beginning, in Introduction the author points out Kozyrev causal mechanics, suggested about fifty years ago, as an inspirable source of ideas devel-oped him at the modern level of rigor.
Evolving Green Aviation Transport System: A Hoilistic Approah to Sustainable Green Market Development  [PDF]
A. N. Sarkar
American Journal of Climate Change (AJCC) , 2012, DOI: 10.4236/ajcc.2012.13014
Abstract: Aviation is one of the fastest growing industries as well as transportation modes in the world. Global aviation contributes about 2% of global greenhouse gas emissions and supports 8% of the world economic activity in terms of GDP. With the phenomenal growth in air trafficking by the national and international airliners the total carbon space available for flying is getting progressively diminished and the consequential emission levels are also becoming alarming over passage of time. The paper describes the concept of evolution of Green Transport system with focus on manufacturing of green aircraft and sustainable green marketing involving green supply chain. This entails introduction of New and innovative technologies, including aircraft designing, improving operational efficiency, air traffic control & monitoring etc; combined with emission mitigation efforts towards sustainable growth of the industry, can make enormous improvements in emission control and reduction in a planned and system-based manner. These integrated approaches are proposed to be used to harmonize the systems and processes that can essentially constitute the suggested framework of the Green Aviation Transport system. The paper, inter alia, discusses various conceptual, strategic, technological and economic and environmental dimensions of the Green Aviation transport system with focus on creating new Green Marketing opportunities for the aviation industry in future.
Theory of pleiotropic action of biologically active compounds and medicines—Basic principles and practical application  [PDF]
N. A. Bizunok
Open Journal of Clinical Diagnostics (OJCD) , 2013, DOI: 10.4236/ojcd.2013.33017
Abstract: This article represents the main positions of the theory of pleiotropic action of biologically active compounds (BACs) and medicines, which has been designed by the author based on her own experimental researches. The term “pleiotropy” means the ability of the BACs and medicines to implement more than one mechanism of action resulting in the specific biological (pharmacological) effect. The interaction of these mechanisms forms a distinct pattern of biological response (pleiotropic pattern), which reflects the change in his character with the increased dose (concentration)-dependent efficacy of BACs and medicines. The article consists of description of different pleiotropic patterns established in experiments on the model of reactive oxygen species (ROS) generation by macrophages dependent on activity of specialized enzyme called Nox2-NAD(P)H oxidase (Nox2, EC 1.6.3.1). Moreover, it consists of explanation of pharmacodynamic nature of pleiotropic patterns by means of application Chou-Talalay median effect equalization and combination index (CI) theory. The novel theory explains unsolved until now universal aspects of activity BACs and medicines, such as slope angles of “dose-effect” dependences in the conditions relevant in vivo, and it is of fundamental interest. However, it has applications in experimental pharmacology, as it allows defining the choice of the individual compounds and combinations, modulating the trust effect selectively and efficiently. This knowledge opens up new approaches to medicines discovery and evaluation, their rational dosing and combining.
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