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Search Results: 1 - 10 of 32288 matches for " Peter Kreins "
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Forecasting the e ects of EU policy measures on the nitrate pollution of groundwater and surface waters

Ralf Kunkel,Peter Kreins,Bjrn Tetzlaff,Frank Wendland,

环境科学学报(英文版) , 2010,
Abstract: We used the interdisciplinary model network REGFLUD to predict the actual mean nitrate concentration in percolation water at the scale of the Weser river basin (Germany) using an area di erentiated (100 m 100 m) approach. REGFLUD combines the agro-economic model RAUMIS for estimating nitrogen surpluses and the hydrological models GROWA/DENUZ for assessing the nitrate leaching from the soil. For areas showing predicted nitrate concentrations in percolation water above the European Union (EU) groundwater quality standard of 50 mg NO3-N/L, e ective agri-environmental reduction measures need to be derived and implemented to improve groundwater and surface water quality by 2015. The e ects of already implemented agricultural policy are quantified by a baseline scenario projecting the N-surpluses from agricultural sector to 2015. The REGFLUD model is used to estimate the e ects of this scenario concerning groundwater and surface water pollution by nitrate. From the results of the model analysis the needs for additional measures can be derived in terms of required additional N-surplus reduction and in terms of regional prioritization of measures. Research work will therefore directly support the implementation of the Water Framework Directive of the European Union in the Weser basin.
Application of two phosphorus models with different complexities in a mesoscale river catchment
F. F. Hattermann, H. G mann, T. Conradt, M. Kaltofen, P. Kreins,F. Wechsung
Advances in Geosciences (ADGEO) , 2007,
Abstract: Central Europe, the focus region of this study, is a region in transition, climatically from maritime to continental and politically from formerly more planning-oriented to more market-oriented management regimes, and in terms of climate change from regions of increasing precipitation in the west and north of Europe to regions of decreasing precipitation in central and southern Europe. The Elbe basin, a trans-boundary catchment flowing from the Czech Republic through Germany into the North Sea, was selected to investigate the possible impacts of global change on crop yields and water resources in this region. For technical reasons, the paper has been split into two parts, the first showing the overall model concept, the model set-up for the agricultural sector, and first results linking eco-hydrological and agro-economic tools for the German part of the basin. The second part describes the model set-up for simulating water supply and demand linking eco-hydrological and water management tools for the entire basin including the Czech part.
Natural Rights, Morality, and the Law  [PDF]
Drum Peter
Beijing Law Review (BLR) , 2011, DOI: 10.4236/blr.2011.21004
Abstract: It is argued that despite attempts to discount the importance of natural rights for morality, they are fundamental to it; therefore, so too are natural rights to the legitimacy of the law.
Price Stability and the Growth Maximizing Rate of Inflation for Ghana  [PDF]
Peter Quartey
Modern Economy (ME) , 2010, DOI: 10.4236/me.2010.13021
Abstract: Monetary policy in Ghana, which is typical of many central banks, over the years, has focused on ensuring price stability or low inflation. The aim of the policy of price stability is to provide a stable environment for real sector activities to flourish. However, the outcome of the policy on real sector activities has not been subjected to any empirical investigation and this forms the focus of the study. For instance, the Central Bank has focused on single digit inflation and whether such a low rate is growth maximizing is yet to be ascertained. The study therefore investigates the revenue maximizing and the ‘growth maximizing’ rate of inflation for Ghana using data from Bank of Ghana and WDI. The study finds that economic performance is higher under low inflation era than when inflation is high. It also established the revenue maximizing rate of inflation using the Laffer curve approach is lower than the growth maximizing rate of inflation. Also, from the results, it can be deduced that the single digit inflation target set by the Central bank is not growth maximizing.
Aristotle’s Definition of Place and of Matter  [PDF]
Peter Drum
Open Journal of Philosophy (OJPP) , 2011, DOI: 10.4236/ojpp.2011.11006
Abstract: The accuracy of Aristotle’s definition of place is defended in terms of his form-matter theory. This theory is in turn defended against the objectionable notion that it entails matter is ultimately characterless.
Adapted Caussinus-Mestre Algorithm for Networks of Temperature series (ACMANT)  [PDF]
Peter Domonkos
International Journal of Geosciences (IJG) , 2011, DOI: 10.4236/ijg.2011.23032
Abstract: Any change in technical or environmental conditions of observations may result in bias from the precise values of observed climatic variables. The common name of these biases is inhomogeneity (IH). IHs usually appear in a form of sudden shift or gradual trends in the time series of any variable, and the timing of the shift indicates the date of change in the conditions of observation. The seasonal cycle of radiation intensity often causes marked seasonal cycle in the IHs of observed temperature time series, since a substantial portion of them has direct or indirect connection to radiation changes in the micro-environment of the thermometer. Therefore the magnitudes of temperature IHs tend to be larger in summer than in winter. A new homogenisation method (ACMANT) has recently been developed which treats in a special way the seasonal changes of IH-sizes in temperature time series. The ACMANT is a further development of the Caussinus-Mestre method, that is one of the most effective tool among the known homogenising methods. The ACMANT applies a bivariate test for searching the timings of IHs, the two variables are the annual mean temperature and the amplitude of seasonal temperature-cycle. The ACMANT contains several further innovations whose efficiencies are tested with the benchmark of the COST ES0601 project. The paper describes the properties and the operation of ACMANT and presents some verification results. The results show that the ACMANT has outstandingly high performance. The ACMANT is a recommended method for homogenising networks of monthly temperature time series that observed in mid- or high geographical latitudes, because the harmonic seasonal cycle of IH-size is valid for these time series only.
Random but System-Wide Unique Unlinkable Parameters  [PDF]
Peter Schartner
Journal of Information Security (JIS) , 2012, DOI: 10.4236/jis.2012.31001
Abstract: When initializing cryptographic systems or running cryptographic protocols, the randomness of critical parameters, like keys or key components, is one of the most crucial aspects. But, randomly chosen parameters come with the intrinsic chance of duplicates, which finally may cause cryptographic systems including RSA, ElGamal and Zero-Knowledge proofs to become insecure. When concerning digital identifiers, we need uniqueness in order to correctly identify a specific action or object. Unfortunately we also need randomness here. Without randomness, actions become linkable to each other or to their initiator’s digital identity. So ideally the employed (cryptographic) parameters should fulfill two potentially conflicting requirements simultaneously: randomness and uniqueness. This article proposes an efficient mechanism to provide both attributes at the same time without highly constraining the first one and never violating the second one. After defining five requirements on random number generators and discussing related work, we will describe the core concept of the generation mechanism. Subsequently we will prove the postulated properties (security, randomness, uniqueness, efficiency and privacy protection) and present some application scenarios including system-wide unique parameters, cryptographic keys and components, identifiers and digital pseudonyms.
Enlarged cauda equina nerve roots in Cerebrotendinous Xanthomatosis  [PDF]
Peter Kalina
Open Journal of Clinical Diagnostics (OJCD) , 2011, DOI: 10.4236/ojcd.2011.13006
Abstract: CXT is a rare inherited autosomal recessive lipid storage disease due to the impaired metabolic pathway of cholesterol secondary to a deficiency in 27- sterol hydroxylase, an enzyme in the synthesis of chenodeoxycholic acid (CDCA), a primary bile acid. Abnormal bile acid synthesis leads to elevated plasma Cholestanol (a derivative of cholesterol) accumulation, especially in the lens, central nervous system (CNS) and tendons.
Spinal Cord Compression by Thoracic Vertebral Hemangioma—A Case Report  [PDF]
Peter Kalina
Open Journal of Medical Imaging (OJMI) , 2012, DOI: 10.4236/ojmi.2012.21005
Abstract: A 68 year old with lower extremity numbness, vibratory sensation loss, coldness and burning of his feet, unsteady gait, frequent falls and a sensory level had an MRI demonstrating aT7 and T8 vertebral body/posterior element lesion with epidural extension, cord compression and foraminal extension (Figures 1-5). Decompressive laminectomy/resection confirmed vertebral hemangioma, a common benign neoplasm that typically remains asymptomatic, found incidentally in 10% of the population. Progressive vertebral body hemangiomas may cause cord or nerve root compression due to epidural tumor extension, expanded bone, hematoma or fracture. Radiographs demonstrate course vertical striations caused by thick trabeculae. CT in indolent lesions demonstrates fat density while compressive lesions demonstrate soft tissue density. Indolent lesions follow fat signal on MRI; symptomatic lesions are T1 isointense/T2 hyperintense. Work-up for aggressive hemangiomas includes angiography to determine vascularity, identify feeding/draining vessels and identify blood supply to the cord. Biopsy helps differentiate hemangioma, lymphoma, myeloma or metastasis. Management of symptomatic hemangiomas includes vertebroplasty for pain, radiation for pain, compression or pre-op and decompressive laminectomy for epidural disease. Embolization of feeding vessels may be performed pre-op or may be curative. Hemangioma causing cord compression and neurologic symptoms by extraosseous extension is much less common than benign hemangioma. Imaging features may suggest potential for progression.
Tay-Sachs and French Canadians: A Case of Gene-Culture Co-evolution?  [PDF]
Peter Frost
Advances in Anthropology (AA) , 2012, DOI: 10.4236/aa.2012.23016
Abstract: Tay-Sachs, an inherited neurological disorder, is unusually common among French Canadians from eastern Quebec. Two alleles are responsible, one being specific to the north shore of the St. Lawrence and the other to the south shore. This pattern of convergent evolution suggests the presence of a selection pressure limited to eastern Quebec. Both alleles probably arose after the British conquest of Quebec in 1759 or at least were uncommon previously. To explain the high incidence of Tay-Sachs among Ashkenazi Jews, some authors have invoked heterozygote advantage, i.e., heterozygous individuals enjoy a higher rate of neuronal growth, and thus greater learning capacity, without the neurological deterioration of homozygous individuals. Such an advantage would have helped Ashkenazim perform the mental effort required for work in trade and crafts. A similar situation may have developed in eastern Quebec, where the relative scarcity of British and American merchants made it easier for French Canadians to enter occupations that required literacy, numeracy, and future time orientation.
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