On the challenge to improve the density response with unusual gradient approximations

Certain excitations, especially ones of long-range charge transfer character, are poorly described by time-dependent density functional theory (TDDFT) when typical (semi-)local functionals are used. A proper description of these excitations would require an exchange-correlation response differing substantially from the usual (semi-)local one. It has recently been shown that functionals of the generalized gradient approximation (GGA) type can yield unusual potentials, mimicking features of the exact exchange derivative discontinuity and showing divergences on orbital nodal surfaces. We here investigate whether these unusual potential properties translate into beneficial response properties. Using the Sternheimer formalism we closely investigate the response obtained with the 2013 exchange approximation by Armiento and K\"ummel (AK13) and the 1988 exchange approximation by Becke (B88), both of which show divergences on orbital nodal planes. Numerical calculations for Na2 as well as analytical and numerical calculations for the hydrogen atom show that the response of AK13 behaves qualitatively different from usual semi local functionals. However, the AK13 functional leads to fundamental instabilities in the asymptotic region that prevent its practical application in TDDFT. Our findings may help the development of future improved functionals, and corroborate that the frequency-dependent Sternheimer formalism is excellently suited for running and analyzing TDDFT calculations

Is a Bimodal Force-Time Curve Related to Countermovement Jump Performance?

A countermovement jump (CMJ) represents one of the most frequently used performance tests for monitoring neuromuscular function in athletes. An often-overlooked feature that may provide some useful diagnostic information is the actual shape of the force-time curve. The aim of this study was therefore to consider how the shape of the force-time curve influences jump performance. Thirty-three male rugby union players performed two CMJs on a force plate, with discrete variables and continuous curve analysis used. The subjects were dichotomized based on shape of the force-time curve during the propulsion phase and by jump height. The differences between the unimodal and bimodal groups were unclear for jump height (ES = 0.28, ±0.58) and reactive strength index-modified (ES = −0.30, ±0.59). A substantial difference between high (40.2 ± 2.9 cm) and low (31.2 ± 3.2 cm) jumpers only existed in the late propulsion phase by 79.0% to 97.0% of the normalized force-time curve. A bimodal force-time curve is not representative of an optimal pattern of performance and simply reflects an inefficient stretch-shortening cycle. The inter-individual variability that exists in braking COM displacement renders temporal phase analysis impractical in cross-sectional type studies

A comparison of catch phase force-time characteristics during clean derivatives from the knee

The aim of this study was to compare load-absorption force-time characteristics of the clean from the knee (CK), power clean from the knee (PCK) and clean pull from the knee (CPK). Ten collegiate athletes (age 27.5 ± 4.2 years; height 180.4 ± 6.7 cm; mass 84.4 ± 7.8 kg), performed three repetitions each of the CK, PCK and CPK with 90% of their 1RM power clean on a force platform. The CK load-absorption duration (0.95 ± 0.35 s) was significantly longer compared to the CPK (0.44 ± 0.15 s; p 0.05, d = 1.08), with no differences between PCK and CPK (p > 0.05, d = 0.91). The CPK demonstrated the greatest mean force (2039 ± 394 N), which was significantly greater than the PCK (1771 ± 325 N; p = 0.012, d = 0.83), but not significantly different to the CK (1830 ± 331 N; p > 0.05, d = 0.60); CK and PCK were not different (p > 0.05, d = 0.18). Significantly more load-absorption work was performed during the CK (655 ± 276 J) compared to the PCK (288 ± 109 J; d = 1.75, p 0.05). Additionally, more load-absorption work was performed during the CPK compared to the PCK (d = 1.90, p = 0.032). Inclusion of the catch phase during the CK does not provide any additional stimulus in terms of mean force or work during the load-absorption phase compared to the CPK, while the CPK may be beneficial in training rapid force absorption due to high force and a short duration

Pairs-Trading: Umsetzung einer quantitativen Handelsstrategie am deutschen Aktienmarkt zur Prüfung der schwachen Markteffizienz

Alternative Investments rückten in den letzten Jahren aufgrund ihres Diversikationseffekts mit traditionellen Anlagen und ihrer guten Performance auch in fallenden Märkten in den Blickpunkt der Investoren. Alleine die Hedge Fonds Branche konnte laut Barclay Hedge das verwaltete Anlagevolumen in den Jahren 1997 bis 2007 von 118,23 Mrd. Dollar auf 2136,83 Mrd. Dollar steigern. Erst im Jahr 2008 sanken die verwalteten Gelder um 678,93 Mrd. Dollar. Auslöser war die Immobilienkrise in den USA, die weltweit den Kapitalmärkten und auch der Hedge Fonds Branche Kursverluste zufügte. Seitdem verzeichnet die Branche wieder jährliche Zuwächse des Anlagevolumens, das von Tausenden von Hedge Fonds, die eine äußerst heterogene Gruppe bilden, verwaltet wird. Eine Hedge Fonds Kategorie, die so genannten Relative-Value-Strategien, nutzt dabei Fehlbewertungen zwischen verbundenen Wertpapieren gewinnbringend aus. Diese Arbeit hat das Ziel, den Erfolg der Pairs-Trading-Strategie, eine Unterkategorie der Relative-Value-Strategien, am deutschen Aktienmarkt zu testen und anschließend zu prüfen, ob die risikoadjustierte Performance mit der schwachen Markteffizienz zu vereinbaren ist.The aim of the following thesis is to test a hedge fund strategy, pairs trading, with daily data over 1997-2007. German stocks a matched into pairs if the difference between their cumulative returns form a stationary process. It shows that the weak market efficieny hypothesis has to be rejected for the investigation period

Paid work, unpaid time prosperity in European welfare regimes

Este estudo visa uma abordagem teórica e empírica com o objectivo de dife renciar quem são os vencedores e os perdedores nas novas formas de trabalho e quais são as novas formas nos quatro regimes de bem-estar europeus. Para tal foram analisados os dados disponíveis da «European Foundation’s 1998 Survey» sobre o horário de trabalho actual e o horário de trabalho preferen cial, a «3rd European Survey» sobre as condições de trabalho no ano 2000, nos 15 países da UE, para além de outras fontes estatísticas nacionais e internacionais

Kulturelles und kommunikatives Gedächtnis. Überlegungen zum Selbstverständnis der Pastoraltheologie in einer Mediengesellschaft

Pastoraltheologie versteht sich heute zumeist als Theorie der Praxis. Sie ist also nicht selber Praxis, sondern der Theoriehorizont von Praxis. Diese Theorie ist handlungsstiftend, bewahrt aber auch vor Handlungsdruck. Pastoraltheologie untersucht die das pastorale Handeln bestimmenden Theoriekonstrukte, etwa die Dekadenztheorie, die davon ausgeht, daß sich alles zum Schlechteren wandelt, die Fortschrittstheorie, die den Fortschritt als dominierende Kategorie der Geschichte annimmt, die Sündenbocktheorie, die schon immer weiß, wer woran schuld ist; aber auch elaboriertere Theorien wie die Säkularisierungstheorie, die von einem Abnehmen religiöser Weltdeutung ausgeht, oder die Modernisierungstheorie, die einen Ubergang von der Moderne in die reflexive Moderne konstatiert. (...)  English Cultural and communicative memory - Reflections on the self-unterstanding of pastoral theology in media-society.Pastoral theology is critized by observers for being a modern disciplin more obliged to modern than to theological reflections. The author in this article tries to proof that pastoral theology coUJ.d fulfil a special task in media-society: to mediate between the cultural and the communicative memory (according to Jan Assmann). Doing this, pastoral theology could save theology from redundance on one siae and save media from the building of clichees. In this way, pastoral theology would be a synchrone corrective for theology and a diachrone one for media