335 research outputs found
Grande Ronde Basin spring chinook salmon captive broodstock program: F₁ generation performance
No full textTim Hoffnagle, Rich Carmichael, Joseph Feldhaus, Deb Eddy, Nick Albrecht, Sally Gee.This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
Do Individuals Recognize Cascade Behavior of Others? - An Experimental Study -
No full textIn an information cascade experiment participants are confronted with artificial predecessors predicting in line with the BHW model (Bikchandani et al., 1992). Using the BDM (Becker et al., 1964) mechanism we study participants' probability perceptions based on maximum prices for participating in the prediction game. We find increasing maximum prices the more coinciding predictions of predecessors are observed, regardless of whether additional information is revealed by these predictions. Individual price patterns of more than two thirds of the participants indicate that cascade behavior of predecessors is not recognized.Information Cascades, Bayes' Rule, Decision Under Risk and Uncertainty, Experimental Economics.
The Uniqueness of Extremum Estimation
No full textLet W denote a family of probability distributions with parameter space Τ, and WG be a subfamily of W depending on a mapping G:Θ -> Τ. Extremum estimations of the parameter vector ν ∈ Θ are considered. Some sufficient conditions are presented to ensure the uniqueness with probability one. As important applications, the maximum likelihood estimation in curved exponential families and nonlinear regression models with independent disturbances as well as the maximum likelihood estimation of the location and scale parameters of Gumbel distributions are treated.Extremum Estimation, Sard’s Theorem, Nonlinear Regression, Curved Exponential Families, Gumbel Distributions.
Formative Measurement Models in Covariance Structure Analysis: Specification and Identification
No full textMany researchers seem to be unsure about how to specify formative measurement models in software programs like LISREL or AMOS and to establish identification of the corresponding structural equation model. In order to make identification easier, a new, mainly graphically oriented approach is presented for a specific class of recursive models with formative indicators. Using this procedure it is shown that some models have erroneously been considered underidentified. Furthermore, it is shown that specifying formative indicators as exogenous variables rises serious conceptual and substantial issues in the case that the formative construct is truly endogenous (i. e. influenced by more remote causes). An empirical study on the effects and causes of brand competence illustrates this point.Formative Indicators; Latent Variables; Covariance Structure Analysis; Identification
Forest storm damage analyses in Southwestern Germany using long-term experimental growth and yield plot data
No full textAufgrund der großen Bedeutung von Sturmschäden für die Waldbewirtschaftung wurde eine bislang noch nicht zur Analyse von Sturmschäden ausgewertete Datengrundlage, die langfristigen waldwachstumskundlichen Versuchsflächen in Baden-Württemberg, analysiert. Die zwei Hauptziele der vorliegenden Dissertation lauteten:
Evaluierung und Erweiterung des bestehenden BWI-Modells für Sturmschäden durch Sturm Lothar in Baden-Württemberg (Schmidt 2006, Schmidt et al. 2009) anhand waldwachstumskundlicher Versuchsflächendaten
Erstellen eines Erklärungs- und Prognosemodells für Sturmschäden anhand langfristiger Sturmschadensdaten waldwachstumskundlicher Versuchsflächen in Baden-Württemberg mit besonderer Berücksichtigung der Schadabhängigkeit von der waldbaulichen Behandlung.
Der Datensatz der langfristigen waldwachstumskundlichen Versuchsflächen beinhaltet ca. 900.000 Baumbeobachtungen zwischen ca. 1890 und 2007 mit Schwerpunkt auf der zweiten Hälfte des 20. Jahrhunderts. In diesem Datensatz sind ca. 20.000 sturmgeschädigte Bäume enthalten, die vorwiegend auf die Stürme Wiebke (1990) und Lothar (1999) entfallen. Eine Differenzierung von Windwurf und Bruch ist nicht dokumentiert. Fichte (47%) und Douglasie (21%) stellen zusammen mit ca. zwei Dritteln den größten Baumartenanteil im gesamten Datensatz dar. Kiefer und Lärche sind zusammen mit ca. 12 %, Buche und Tanne mit je ca. 8 % vertreten. Geringe Anteile entfallen auf die Eiche (ca. 2%). Die Besonderheit des Datensatzes liegt in der gleichzeitigen Verfügbarkeit einzelbaumweiser und bestandesweiser dendrometrischer Größen sowie Informationen über die waldbaulichen Eingriffe. Bei der Auswertung kamen CART-Methoden (classification and regression trees, Entscheidungsbäume) und statistische Modellierung zum Einsatz.
Das Vorgehen bei der statistischen Modellierung kann folgendermaßen charakterisiert werden: Im Rahmen der Erweiterung des vorhandenen BWI-Modells für Schäden durch Sturm Lothar (Ziel 1) wurde getestet, ob Prädiktoren der Versuchsflächendaten, die bei der Entwicklung des BWI-Modells nicht zur Verfügung standen, weitere Beiträge zur Erklärung von Sturmschäden liefern. Im Rahmen der Erstellung des Erklärungs- und Prognosemodells anhand langfristiger Versuchsflächendaten (Ziel 2) wurde ein vierstufiges Modellierungskonzept eingesetzt, um das Auftreten von Sturmschäden allgemein, das Auftreten von flächigen Sturmschäden sowie das Auftreten von Einzelbaum- und kleinflächigen Schäden zu untersuchen.
Die wesentlichen Ergebnisse bezüglich der Evaluierung des BWI-Modells anhand von Versuchsflächendaten für Sturm Lothar (Ziel 1) lieferten die Erkenntnis, dass die im Modell enthaltenen Effekte auch die Trends in den Versuchsflächendaten korrekt wiedergeben. Insgesamt überschätzte das BWI-Modell das Sturmrisiko auf den Versuchsflächen jedoch mäßig. Im Zuge der Modellerweiterung wurde festgestellt, dass insbesondere die eingriffsbasierten Variablen deutliche Modellverbesserungen erlauben.
Im Zuge der Erstellung des Erklärungs- und Prognosemodells für Sturmschäden anhand langfristiger Versuchsflächendaten (Ziel 2) zeigten sich folgende Ergebnisse:
- Die Baumarten- und Baumhöheneffekte haben auch für die Erklärung von Sturmschäden mehrerer Sturmereignisse den größten Einfluss.
- Der erhebliche Einfluss (ca. 20%) der waldbaulichen Eingriffe ließ sich vorwiegend durch die relative Entnahmestärke während der fünf bzw. zehn Jahre vor dem Sturmereignis quantifizieren.
- Die Wirkung des Durchforstungsquotienten im Modell weist insbesondere bei größeren Bestandeshöhen (Vorratspflege) auf labilisierende Einflüsse von Eingriffen ins Herrschende hin.
- Die einzelbaum- und bestandesweisen h/d-Werte lieferten widersprüchliche Ergebnisse. H/d-Werte werden generell als ungeeignet für die Beschreibung von Sturmschäden bzw. Windwurfschäden eingestuft. Eine Trennung von Bruch- und Wurfschäden war im Datenmaterial nicht dokumentiert und daher in der Analyse nicht abbildbar.
- Die Sturmgefährdung der Douglasie erscheint auf der Grundlage der Versuchsflächendaten mindestens ebenso hoch wie die der Fichte. Die deutlich höheren Schadensanteile bei Douglasie im Vergleich mit denen der Fichte sind mutmaßlich auf standörtliche Verhältnisse zurückzuführen, so dass die Annahme generell höherer Sturmschadensdisposition für Douglasie verfrüht wäre.
- Einzelbaumdaten besitzen offensichtlich geringen Erklärungswert für das Sturmrisiko, sofern bestandesweise präzise Kenngrößen vorliegen.
Es folgt die Diskussion des Datenmaterials, der verwendeten Methoden und der Übertragbarkeit der Ergebnisse. Aus den Ergebnissen werden Schlussfolgerungen für die waldbauliche Behandlung aus Sicht der Sturmrisikominimierung sowie für die Sturmschadensforschung abgeleitet.
Due to the severe impact of storm damage on forest management, this dissertation focuses on the analysis of storm damage based on data from long-term experimental growth and yield plots in Southwestern Germany. The two main objectives of this study are:
- Evaluation and extension of an existing storm damage model (Schmidt) using experimental plot data. The existing storm damage model had originally been developed based on systematic sample data of the National Forest Inventory (NFI) describing storm damage of the 1999 winter storm ‘Lothar’.
- Modeling storm damage based on the long-term experimental plot data containing several storm events, with special focus on the impact of silvicultural interventions on the severity of storm damage.
The data set of the long-term experimental growth and yield plots contain 900,000 observations between 1890 and 2007, primarily after 1950. It contains approximately 20,000 trees damaged predominantly by two storms in 1990 and 1999. Windthrow and snap are not documented separately. Norway spruce (47%) and Douglas fir (21%) constitute two thirds of the data, Scots pine and larch species (European and Japanese larch) together amount to 12 %, and European beech and Silver fir each represent 8 %. Oak species (Sessile and Pedonculate oak) only represent a small proportion of the data (2 %). Special features of the data source are the availability of dendrometric single tree and stand data as well as precise documentation of the silvicultural interventions. For the analyses we applied data mining methods and statistical empirical modeling.
The modeling approaches of the two main objectives can be characterized as follows:
For the extension of the existing NFI-model for single storm damage data (1999 storm) additional potential predictor variables in the experimental plot data were tested, which had not been available with the original NFI data. Model improvement by those predictors was quantified.
A four-stage modeling concept was applied to model storm risk of the long-term experimental plot data, analyzing the general occurrence of storm damage and the occurrence of total, partial and tree-level storm damage.
Results
Evaluating the existing NFI-model for single storm event data showed good general correspondence between the modeled effects and the observed phenomena responsible for storm damage in the experimental plot data (only 1999 damage data). In total, though, the NFI model overestimated storm risk for the experimental plots moderately. Including two additional predictor variables that were only available in the experimental plot data improved model predictions to a medium extent.
Developing the modeling system for the long-term damage data yielded the following results:
- The effects of tree species and tree height have the largest impact on storm damage data, even if considering multiple damage events.
- The significant influence of silvicultural interventions (approximately 20%) can be quantified by the relative intensity of thinnings during the five, and sometimes up to ten years preceding the storm event.
- The effect of the thinning quotient (mean diameter of removed trees/mean diameter of all trees prior to thinning) suggests that interventions removing trees from the dominant classes significantly destabilize stands, especially during the late stand developmental phases when the stands have reached considerable stand heights.
- The single tree and stand-specific h/d ratios had inconsistent effects. While the h/d ratio may be unsuitable for characterizing the dynamic phenomena involved in turnover, it is assumed that it indicates rather well the more static incident of stem snap. However, these two different forms of storm damage were not recorded separately in the data and could consequently not be differentiated.
- The storm risk of Douglas fir appears to be at least as high as the risk of Norway spruce, based on experimental plot data. While the storm damage in Douglas fir stands even exceeded the damage encountered in Norway spruce stands, it should not be concluded that Douglas fir as a tree species is generally more prone to storm damage then Norway spruce. The reason is that the Douglas fir stands in the experimental plot data on average grow on sites that are in general considered more difficult for developing a deep root architecture and thus tend to develop less firm anchorage than on the Norway spruce sites.
- Single tree data apparently carry little information explaining storm risk, if precise stand level data are available.
A discussion of the reliability of the data sources and the suitability of the applied methods follows the presentation of the results. Conclusions for the silvicultural treatment – from the viewpoint of minimizing storm risk – and for storm damage research are deduced from these results
Engineered nanopores for bioanalytical applications /
No full textThis book is the first to explore both the development and application of nanopores with practical analytical applications as the primary focus. These nanoscale analytical techniques have exciting potential as they can be used in applications such as DNA sequencing, DNA fragment sizing, DNA/protein binding, and protein/protein binding. Importantly this book aims to provide a solid professional reference on nanopores for readers in both academia and industry, and engineering and biomedical fields. In addition, the aim of this book is to share with the scientific and engineering communities the experimental and fabrication methods necessary to carry out nanopore-based experiments for developing new devices. Includes application case studies for detection, identification and analysis of biomolecules and related functional nanomaterials Introduces the techniques of manufacturing solid state materials with functional nanopores Explains the use of nanopores in DNA sequencing and the wider range of applications from environmental monitoring to forensics.This book is the first to explore both the development and application of nanopores with practical analytical applications as the primary focus. These nanoscale analytical techniques have exciting potential as they can be used in applications such as DNA sequencing, DNA fragment sizing, DNA/protein binding, and protein/protein binding. Importantly this book aims to provide a solid professional reference on nanopores for readers in both academia and industry, and engineering and biomedical fields. In addition, the aim of this book is to share with the scientific and engineering communities the experimental and fabrication methods necessary to carry out nanopore-based experiments for developing new devices. Includes application case studies for detection, identification and analysis of biomolecules and related functional nanomaterials Introduces the techniques of manufacturing solid state materials with functional nanopores Explains the use of nanopores in DNA sequencing and the wider range of applications from environmental monitoring to forensics.Print version record.Includes bibliographical references and index.Chapter 1. Ion transport in nanopores / T. Albrecht, T. Gibb and P. Nuttall -- chapter 2. DNA translocation / Oliver Otto and Ulrich F. Keyser -- chapter 3. Instrumentation for low-noise high-bandwidth nanopore recording / Vincent Tabard-Cossa -- chapter 4. Biological pores on lipid bilayers / Joseph W.F. Robertson -- chapter 5. Solid-state nanopore fabrication / Thomas Gibb and Mariam Ayub -- chapter 6. Case studies using solid-state pores / Gaurav Goyal [and three others].Elsevie
The Role of Highly-Resolved Gust Speed in Simulations of Storm Damage in Forests at the Landscape Scale: A Case Study from Southwest Germany
No full textRoutinely collected booking records of salvaged timber from the period 1979–2008 were used to empirically model the (1) storm damage probability; (2) proportions of storm-damaged timber and (3) endemic storm damage risk in the forest area of the German federal state of Baden-Wuerttemberg by applying random forests. Results from cross-validated predictor importance evaluation demonstrate that the relative impact of modeled gust speed fields on the predictive accuracy of the random forests models was greatest compared to the impact of forest and soil features. Forest areas prone to storm damage occurring within a period of five years were mainly located in mountainous upland regions where maximum gust speed exceeds 31 m/s in a five-year return period and conifers dominate the tree species composition. While mean storm damage probability continuously increased with increasing statistical gust speed proportions of storm-damaged timber peaked at a statistical maximum gust speed value of 29 m/s occurring in a five-year return period. Combining the statistical gust speed field with daily gust speed fields of two exceptional winter storms improved model accuracy and considerably increased the explained variance. Endemic storm damage risk was calculated from endemic storm damage probability and proportions of endemically storm-damaged timber. In combination with knowledge of local experts the storm damage risk modeled in a 50 m × 50 m resolution raster dataset can easily be used to identify areas prone to storm damage and to adapt silvicultural management regimes to make forests more windfirm
Review on the projections of future storminess over the North Atlantic European region
No full textThis is an overview of the results from previously published climate modeling studies reporting on projected aspects of future storminess over the North Atlantic European region (NAER) in the period 2020–2190. Changes in storminess are summarized for seven subregions in the study area and rated by a categorical evaluation scheme that takes into account emission scenarios and modeling complexity in the reviewed studies. Although many of the reviewed studies reported an increase in the intensity of high-impact wind speed and extreme cyclone frequency in the second half of the 21st century, the projections of aspects of future storminess over the NAER differed regionally. There is broad consensus that the frequency and intensity of storms, cyclones, and high-impact wind speed will increase over Central and Western Europe, and these changes will probably have the potential to produce more damage. In contrast, future extratropical storminess over Southern Europe is very likely to decrease. For Northern and Eastern Europe the results of the evaluation are inconclusive, because there is an indication of increasing as well as decreasing development of the evaluated aspects of future storminess. Concerning the storm track, we found indications of a likely north- and eastward shift in most assessed studies. Results from three studies suggest a northeastward shift of the North Atlantic Oscillation
Light absorption and light-use efficiency in mixtures of Abies alba and Picea abies along a productivity gradient
No full textImproving empirical storm damage models by coupling with high-resolution gust speed data
No full text- …
