Uncertainties and shortcomings of ground surface temperature histories derived from inversion of temperature logs

Analysing borehole temperature data in terms of ground surface history can add useful information to reconstructions of past climates. Therefore, a rigorous assessment of uncertainties and error sources is a necessary prerequisite for the meaningful interpretation of such ground surface temperature histories. This study analyses the most prominent sources of uncertainty. The diffusive nature of the process makes the inversion relatively robust against incomplete knowledge of the thermal diffusivity. Similarly the influence of heat production is small. It turns out that for investigations of the last 1000 to 100000 years the maximum depth of the temperature log is crucial. More than 3000 m are required for an optimal inversion. Reconstructions of the last one or two millennia require only modestly deep logs (>300 m) but suffer severely from noisy data.Comment: 28 pages, 18 figure, 3 table

KnowSe: Fostering user interaction context awareness

The CSCW area has recognized the concept of awareness as a critical issue to focus on (Schmidt et al., 2002) since “users who work together require adequate information about their environment” (Gross and Prinz, 2003). The environment of an individual encompasses her connections with other people, as well as with digital resources and actions (tasks or processes). If connections are not clear or hidden to the individual or to the group, the cost is a lack of awareness in the organization (McArthur and Bruza, 2003), which not only leads to inefficient cooperation but can even prevent it from being started. Unveiling the relations between persons, topics, tasks and processes to computer workers facilitates cooperative work by increasing the awareness of the personal social networks and the role of an individual in the organization, a project, or a group. These connections can be created and modeled manually but a better approach is to develop semi-automatic or even automatic tools to create and share them (McArthur and Bruza, 2003). Based on emails, McArthur and Bruza (2003) have computed such kind of connections, and suggest using more global corpora as well as taking into account dynamic ones

Detecting real user tasks by training on laboratory contextual attention metadata

Detecting the current task of a user is essential for providing her with contextualized and personalized support, and using Contextual Attention Metadata (CAM) can help doing so. Some recent approaches propose to perform automatic user task detection by means of task classifiers using such metadata. In this paper, we show that good results can be achieved by training such classifiers offline on CAM gathered in laboratory settings. We also isolate a combination of metadata features that present a significantly better discriminative power than classical ones

Exploiting the user interaction context for automatic task detection

Detecting the task a user is performing on her computer desktop is important for providing her with contextualized and personalized support. Some recent approaches propose to perform automatic user task detection by means of classifiers using captured user context data. In this paper we improve on that by using an ontology-based user interaction context model that can be automatically populated by (i) capturing simple user interaction events on the computer desktop and (ii) applying rule-based and information extraction mechanisms. We present evaluation results from a large user study we have carried out in a knowledge-intensive business environment, showing that our ontology-based approach provides new contextual features yielding good task detection performance. We also argue that good results can be achieved by training task classifiers `online' on user context data gathered in laboratory settings. Finally, we isolate a combination of contextual features that present a significantly better discriminative power than classical ones

Thermal Conductivity from Core and Well log Data

The relationships between thermal conductivity and other petrophysical properties have been analysed for a borehole drilled in a Tertiary Flysch sequence. We establish equations that permit us to predict rock thermal conductivity from logging data. A regression analysis of thermal conductivity, bulk density, and sonic velocity yields thermal conductivity with an average accuracy of better than 0.2 W/(m K). As a second step, logging data is used to compute a lithological depth profile, which in turn is used to calculate a thermal conductivity profile. From a comparison of the conductivity-depth profile and the laboratory data it can be concluded that thermal conductivity can be computed with an accuracy of less than 0.3 W/(m K)from conventional wireline data. The comparison of two different models shows that this approach can be practical even if old and incomplete logging data is used. The results can be used to infer thermal conductivity for boreholes without appropriate core data that are drilled in a similar geological setting.Comment: 18 pages, 9 figure, 3 table

Automatic detection of accommodation steps as an indicator of knowledge maturing

Jointly working on shared digital artifacts – such as wikis – is a well-tried method of developing knowledge collectively within a group or organization. Our assumption is that such knowledge maturing is an accommodation process that can be measured by taking the writing process itself into account. This paper describes the development of a tool that detects accommodation automatically with the help of machine learning algorithms. We applied a software framework for task detection to the automatic identification of accommodation processes within a wiki. To set up the learning algorithms and test its performance, we conducted an empirical study, in which participants had to contribute to a wiki and, at the same time, identify their own tasks. Two domain experts evaluated the participants’ micro-tasks with regard to accommodation. We then applied an ontology-based task detection approach that identified accommodation with a rate of 79.12%. The potential use of our tool for measuring knowledge maturing online is discussed

Oppositionstradition versus Regierungsverantwortung : Die Positionen der SPD in der Außen- und Sicherheitspolitik zwischen 1993 und 2005

Die SPD trug im Laufe ihrer Geschichte zu verschiedenen Zeitpunkten Regierungsverantwortung. Doch jedes Mal tat sie sich schwer mit der Bürde der administrativen Staatslenkung. Oftmals waren Schwierigkeiten bei der Gewöhnung an die Regierungstätigkeit schon nach kurzer Zeit erkennbar. Außerdem war es immer von Bedeutung, ob die SPD während ihrer Regierungszeit den Bundeskanzler stellte, oder ob sie der Bundesregierung lediglich als Juniorpartner angehörte. Die vorliegende Arbeit stellt die Positionen der SPD in der Außen- und Sicherheitspolitik während der Oppositionsjahre von 1993 bis 1998 sowie während der nächsten sieben Jahre in wiedererlangter Regierungsverantwortung von 1998 bis 2005 dar. Die Arbeit untersucht, ob die SPD als Partei bzw. die wesentlichen Akteure der SPD im Jahre 1998 im Bereich der Außen- und Sicherheitspolitik auf die Übernahme von Regierungsverantwortung vorbereitet gewesen sind. Beschrieben werden zunächst die Jahre von der Gründung der deutschen Sozialdemokratie 1863 bis 1993 in einem Überblick. Schwerpunkt dieser Betrachtung bilden die außenpolitischen Grundsatzentscheidungen sowie die Probleme, die die SPD während dieser Zeit bei der Realisierung von Oppositionswünschen im praktischen Regierungshandeln zwischen 1969 und 1982 hatte. Darauf folgt dann die eingehende Analyse der Jahre von 1993 bis 2005. Mit der Untersuchung dieses Zeitraumes soll der Versuch gemacht werden, fünf Jahre vor Regierungseintritt mit den Jahren in Regierungsverantwortung (als "Kanzlerpartei" und Partei zweier sozialdemokratischer Verteidigungsminister) zu vergleichen. Der Fokus richtet sich zum einen auf die Entscheidungen, welche die SPD auf den Parteitagen traf. Zum anderen stehen die Diskussionen im Parteivorstand, im Präsidium und im Parteirat im Zentrum der Betrachtung. Zu diesem Zweck analysiert die Arbeit unter anderem eine umfangreiche Sammlung von Parteitagsprotokollen und Parteitagsbeschlüssen sowie Protokolle der Sitzungen des Präsidiums, des Parteivorstandes und des Parteirates, aber auch die Regierungsprogramme im Vorfeld der Bundestagswahlen 1994, 1998, 2002 und 2005. Dadurch werden die zu den jeweiligen Zeitpunkten aktuellen Meinungen sozusagen "ungefiltert" erkennbar. Ferner wird auf Protokolle von Plenarsitzungen des Deutschen Bundestages und auf eine vielschichtige Auswahl von Presseartikeln zurückgegriffen. Daraus wird ersichtlich, welche Kompromisse gebildet wurden oder eben nicht, wie sich einzelne Akteure verhielten, mit welcher Intensität die Delegierten der Bundesparteitage hinter der Positionsfindung der Parteiführung standen - oder eben nicht standen - und wie die Öffentlichkeit auf die Entscheidungen reagierte. Neben diesen Quellen haben sich maßgebliche Akteure der SPD-Außenpolitik im zu untersuchenden Zeitraum bereit erklärt, zur Außen- und Sicherheitspolitik der SPD Rede und Antwort zu stehen. Diese Interviews sind für den Verfasser der Arbeit eine große Stütze, um zu einer wirklich umfassenden Würdigung des Themas zu gelangen. Es ist eine Herausforderung, die Jahre, in denen Sozialdemokraten zum ersten Mal in der über 140-jährigen Parteigeschichte über den Einsatz von Militär im Ausland entscheiden mussten, zu analysieren. Interessant für die nahe Zukunft wird allerdings sein, welche Konsequenzen die SPD selbst aus den dargestellten Ereignissen noch ziehen wird

Stimulation of adventitious root formation by laser wounding in rose cuttings: A matter of energy and pattern

Adventitious root (AR) formation is the basis of vegetative propagation in rose, be it via stem cuttings or via stenting. During this process, wounding plays a pivotal role since cell reprogramming takes place at the tissue adjacent to the wound. We investigated the effects of wounding on AR formation on leafy single-node stem cuttings of the rose rootstock R. canina ‘Pfänder’ (codes R02-3 and R02-6) and the cut rose cultivar Rosa ‘Tan09283’ (Registration name ‘Beluga’). Laser wounding treatments were based on the assisted removal of tissue layers located in the bark. The positioning of wounding was studied based on two marking directions: along the cutting base (strip pattern) and around the cutting base (ring pattern). Additionally, the effects of external supply of indole-butyric acid (IBA 1 mg L-1) on rooting were analyzed. Results showed that in order to remove specific tissue layers, the calculation of the laser energy density (J cm-2) in terms of cutting diameter was necessary. Interestingly, the application of energy densities from 2.5 J cm-2 up to approximately 8.5 J cm-2 were sufficient to expose the tissue layers of epidermis up to regions of phloem. Regarding AR formation for R. canina ‘Pfänder’, characterized by a low rooting response, an increase in the rooting percentage was registered when the laser treatment eliminated the tissue up to phloem proximities. Analysis of the nodal position showed that bud location was a preferential place for AR formation independently of wounding treatment. In case of Rosa ‘Tan09283’, laser treatments did not reduce its high rooting capacity, but an apparent reduction in rooting quality due to an investment in tissue healing was observed when wounding reached deeper layers such as parenchyma and sclerenchyma. Results also showed a strong AR formation directly from wounded regions in case of Rosa ‘Tan09283’ specifically when the wound was located below the axillary bud. In conclusion, wounding by assisted-elimination of layers by laser can induce positive effects on AR formation of single-node stem cuttings of the rose if energy applied is able to expose phloem proximities, a longitudinal orientation, and relative position to the axillary bud are considered

Importance sampling of randomized measurements for probing entanglement

We show that combining randomized measurement protocols with importance sampling allows for characterizing entanglement in significantly larger quantum systems and in a more efficient way than in previous work. A drastic reduction of statistical errors is obtained using classical techniques of machine-learning and tensor networks using partial information on the quantum state. In present experimental settings of engineered many-body quantum systems this effectively doubles the (sub-)system sizes for which entanglement can be measured. In particular, we show an exponential reduction of the required number of measurements to estimate the purity of product states and GHZ states.Comment: 6+6 pages, 3+4 figures, accepted version. Code available at https://github.com/bvermersch/RandomMea