593 research outputs found
Land Use Change in Europe- Scenarios for a Project Area in East Germany, Poland and the Czech Republic
This study identifies plausible scenarios for land use changes for a project area located at the coexistent borders of Poland, the Czech Republic and East Germany. The time frame is 1992 to 2050 with an intermediate step in 2020. The basis for the scenarios is an analysis of the driving forces for land use change in the context of the study area. The main emphasis here is on the EU's Common Agricultural Policy and trends in agriculture and forestry in the three countries of the project area. In addition former land use change, spread of urban areas, the state of mining areas, recreation and nature conservation and policies related to land use planning are of importance and therefore analyzed for each country.
The direction of land use change between 1960 and present was a decrease in agricultural land and an increase in forest and 'other' area, which mainly consists of urban area and area for infrastructure. Recent changes in the Common Agricultural Policy aim at reducing overproduction an cut spending in general. The prevailing tendency is to liberalize the agricultural sector to shift from product tied payments to direct payments to farmers for social, environmental or cultural duties. Since the political changes in 1989 the three countries of the project area have undergone significant economic and structural changes. East Germany as part of Unified Germany and part of the EU has experienced the most drastic restructuring of the agricultural sector with the main feature of major job losses and production decreases, especially in the livestock sector. Similar developments, though not as radical, can be observed in Poland and the Czech Republic.
The first Scenario, "Large Scale Increase of Wooded Area", anticipates the introduction of a free market economy to the agricultural sector. No more subsidies are required for agriculture. Large areas of marginal farmland have to be taken out of production. The price of land decreases. Farmers will either afforest their farmland or sell it to non-agricultural uses like urban development, recreation or nature conservation are options for farmers. A quantification for the project area foresees by 2050 a decrease of agricultural land to half of its size in 1992, a doubling of forest and an increase of 'other' area by 80%.
Scenario 2, "Alternative Agricultural Products", assumes a shift from food production to nonfood products, mainly biofuel and incentives for an extensification of agricultural production. Subsidies, that are still required for the agricultural sector, will be kept. The overall policy aims at keeping the land open, avoiding uncontrolled spreading of urban development and providing prospect for development and employment in rural areas.
The main characteristic of Scenario 3, "Europe as Food Exporter", is an increase in the demand for agricultural products, which by approximately 2010 triggers a increase in the world market price for food products. Reasons for this are population and wealth increase, especially in China an south east Asia, combined with environmental constraints like water or fertile land scarcity and erosion. As a result agricultural production in Europe becomes prosperous in the frame of a free market environment. No further subsidies are required for the sector. Until 2010 the development is similar to Scenario 2. Scenario 2 and 3 show only modest changes in land use patterns, but the agricultural production structure differs. Scenario 2 focuses on a mixture of food and non-food products, while in Scenario 3 all available farmland is used for food production after 2010
Hierarchically nested factor model from multivariate data
We show how to achieve a statistical description of the hierarchical
structure of a multivariate data set. Specifically we show that the similarity
matrix resulting from a hierarchical clustering procedure is the correlation
matrix of a factor model, the hierarchically nested factor model. In this
model, factors are mutually independent and hierarchically organized. Finally,
we use a bootstrap based procedure to reduce the number of factors in the model
with the aim of retaining only those factors significantly robust with respect
to the statistical uncertainty due to the finite length of data records.Comment: 7 pages, 5 figures; accepted for publication in Europhys. Lett. ; the
Appendix corresponds to the additional material of the accepted letter
Predictors of self-rated health: a 12-month prospective study of IT and media workers
OBJECTIVE: The aim of the present study was to determine health-related risk and salutogenic factors and to use these to construct prediction models for future self-rated health (SRH), i.e. find possible characteristics predicting individuals improving or worsening in SRH over time (0â12 months). METHODS: A prospective study was conducted with measurements (physiological markers and self-ratings) at 0, 6 and 12 months, involving 303 employees (187 men and 116 women, age 23â64) from four information technology and two media companies. RESULTS: There were a multitude of statistically significant cross-sectional correlations (Spearman's Rho) between SRH and other self-ratings as well as physiological markers. Predictors of future SRH were baseline ratings of SRH, self-esteem and social support (logistic regression), and SRH, sleep quality and sense of coherence (linear regression). CONCLUSION: The results of the present study indicate that baseline SRH and other self-ratings are predictive of future SRH. It is cautiously implied that SRH, self-esteem, social support, sleep quality and sense of coherence might be predictors of future SRH and therefore possibly also of various future health outcomes
Spanning Trees and bootstrap reliability estimation in correlation based networks
We introduce a new technique to associate a spanning tree to the average
linkage cluster analysis. We term this tree as the Average Linkage Minimum
Spanning Tree. We also introduce a technique to associate a value of
reliability to links of correlation based graphs by using bootstrap replicas of
data. Both techniques are applied to the portfolio of the 300 most capitalized
stocks traded at New York Stock Exchange during the time period 2001-2003. We
show that the Average Linkage Minimum Spanning Tree recognizes economic sectors
and sub-sectors as communities in the network slightly better than the Minimum
Spanning Tree does. We also show that the average reliability of links in the
Minimum Spanning Tree is slightly greater than the average reliability of links
in the Average Linkage Minimum Spanning Tree.Comment: 17 pages, 3 figure
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Recent Revisions to PVWATTS
PVWATTS is an Internet-accessible software program that allows the user to easily calculate the energy production and cost savings for grid-connected photovoltaic (PV) systems located throughout the United States. To ensure that PVWATTS continues to meet its users' needs, an online survey form was provided to users to identify areas for improvement. The results of the survey were used to prioritize improvements to PVWATTS in FY2005. PVWATTS was revised by changing the PV system specification input for system size from an AC power rating to a nameplate DC power rating; adding an input for an overall DC to AC derate factor; updating the residential electric rates; adding monthly and yearly solar radiation values for the PV array; and simplifying the user interface for Version 2
Proposal for a Performance Dashboard for the Monitoringof Water and Sewage Service Companies (WaSCs)
The water and sewage industry provides an essential service to the community, but it is characterized by natural monopoly tendencies of service suppliers. In this framework, it is very important to assist regulators with a small set of critical indicators (performance dashboard) for the evaluation and monitoring of the service provided by Water and Sewage Companies (WaSCs). The paper originates from the analysis of situation of Piemonte (Italy), where each regional and local body adopts a proprietary Performance Measurement System (PMS). In order to improve the coordination of information flow and to support the definition of common service standards, a methodology to merge existing PMSs and define a unique shared reference system is proposed. The Kaplan and Norton's Balanced Scorecard (BSC) is adopted as the reference model of this approach. BSC is widely recognized to be an exhaustive and balanced framework in describing the performances of an organization and ensures that all the operational aspects of WaSCs are adequately monitored. The output of the proposed procedure is a general performance dashboard for the monitoring of WaSCs. The dashboard is shown and some remarks about indicators properties are developed. In particular, this analysis highlights some common pitfalls originated by a ârushed' aggregation of several performance indicators. Description is supported by several example
Cost-effectiveness of alternative methods of surgical repair of inguinal hernia
Objectives: To assess the relative cost-effectiveness of laparoscopic methods of inguinal hernia repair compared with open flat mesh and open non-mesh repair. Methods: Data on the effectiveness of these alternatives came from three systematic reviews comparing: (i) laparoscopic methods with open flat mesh or non-mesh methods; (ii) open flat mesh with open non-mesh repair; and (iii) methods that used synthetic mesh to repair the hernia defect with those that did not. Data on costs were obtained from the authors of economic evaluations previously conducted alongside trials included in the reviews. A Markov model was used to model cost-effectiveness for a five-year period after the initial operation. The outcomes of the model were presented using a balance sheet approach and as cost per hernia recurrence avoided and cost per extra day at usual activities. Results: Open flat mesh was the most cost-effective method of preventing recurrences. Laparoscopic repair provided a shorter period of convalescence and less long-term pain compared with open flat mesh but was more costly. The mean incremental cost per additional day back at usual activities compared with open flat mesh was âŹ38 and âŹ80 for totally extraperitoneal and transabdominal preperitoneal repair, respectively. Conclusions: Laparoscopic repair is not cost-effective compared with open flat mesh repair in terms of cost per recurrence avoided. Decisions about the use of laparoscopic repair depend on whether the benefits (reduced pain and earlier return to usual activities) outweigh the extra costs and intraoperative risks. On the evidence presented here, these extra costs are unlikely to be offset by the short-term benefits of laparoscopic repair.Luke Vale, Adrian Grant, Kirsty McCormack, Neil W. Scott and the EU Hernia Trialists Collaboratio
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Long-Term Performance Data and Analysis of CIS/CIGS Modules Deployed Outdoors
The long-term performance data of copper indium diselenide (CIS) and gallium-alloyed CIS (CIGS) photovoltaic (PV) modules are investigated to assess the reliability of this technology
Ward's Hierarchical Clustering Method: Clustering Criterion and Agglomerative Algorithm
The Ward error sum of squares hierarchical clustering method has been very
widely used since its first description by Ward in a 1963 publication. It has
also been generalized in various ways. However there are different
interpretations in the literature and there are different implementations of
the Ward agglomerative algorithm in commonly used software systems, including
differing expressions of the agglomerative criterion. Our survey work and case
studies will be useful for all those involved in developing software for data
analysis using Ward's hierarchical clustering method.Comment: 20 pages, 21 citations, 4 figure
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