A New Technique for Firn Grain-Size Measurement Using SEM Image Analysis

Firn microstructure is accurately characterized using images obtained from scanning electron microscopy (SEM). Visibly etched grain boundaries within images are used to create a skeleton outline of the microstructure. A pixel-counting utility is applied to the outline to determine grain area. Firn grain sizes calculated using the technique described here are compared to those calculated using the techniques of Cow (1969) and Gay and Weiss (1999) on samples of the same material, and are found to be substantially smaller. The differences in grain size between the techniques are attributed to sampling deficiencies (e.g. the inclusion of pore filler in the grain area) in earlier methods. The new technique offers the advantages of greater accuracy and the ability to determine individual components of the microstructure (grain and pore), which have important applications in ice-core analyses. The new method is validated by calculating activation energies of grain boundary diffusion using predicted values based on the ratio of grain-size measurements between the new and existing techniques. The resulting activation energy falls within the range of values previously reported for firn/ice.

Grazing response patterns indicate isolation of semi-natural European grasslands

Identifying drivers of species diversity is a major challenge in understanding and predicting the dynamics of species-rich semi-natural grasslands. In particular in temperate grasslands changes in land use and its consequences, i.e. increasing fragmentation, the on-going loss of habitat and the declining importance of regional processes such as seed dispersal by livestock, are considered key drivers of the diversity loss witnessed within the last decades. It is a largely unresolved question to what degree current temperate grassland communities already reflect a decline of regional processes such as longer distance seed dispersal. Answering this question is challenging since it requires both a mechanistic approach to community dynamics and a sufficient data basis that allows identifying general patterns. Here, we present results of a local individual- and trait-based community model that was initialized with plant functional types (PFTs) derived from an extensive empirical data set of species-rich grasslands within the `Biodiversity Exploratories' in Germany. Driving model processes included above- and belowground competition, dynamic resource allocation to shoots and roots, clonal growth, grazing, and local seed dispersal. To test for the impact of regional processes we also simulated seed input from a regional species pool. Model output, with and without regional seed input, was compared with empirical community response patterns along a grazing gradient. Simulated response patterns of changes in PFT richness, Shannon diversity, and biomass production matched observed grazing response patterns surprisingly well if only local processes were considered. Already low levels of additional regional seed input led to stronger deviations from empirical community pattern. While these findings cannot rule out that regional processes other than those considered in the modeling study potentially play a role in shaping the local grassland communities, our comparison indicates that European grasslands are largely isolated, i.e. local mechanisms explain observed community patterns to a large extent.

Improving memory in elderly adults by instructing them in professional actors' learning strategies

This study examined a new type of cognitive intervention. For four weeks, participants (ages 65 to 82) were instructed in professional acting techniques, followed by rehearsal and performance of theatrical scenes. Although the training was not targeted in any way to the tasks used in pre- and post-testing, participants produced significantly higher recall and recognition scores after the intervention. It is suggested that the cognitive effort involved in analyzing and adopting theatrical characters' motivations (and then experiencing those characters' mental/emotional states during performance) is responsible for the observed improvement. A secondary strand of this study showed that participants who were given annotated scripts in which the implied goals of the characters were made explicit demonstrated significantly faster access to the stored material, as measured by a computer latency task.

Impact of Earth radiation pressure on LAGEOS orbits and on the global scale

The indirect solar radiation pressure caused by reflected or re-emitted radiation by the Earth’s surface is an important non-gravitational force perturbing the orbits of geodetic satellites (Rubincam and Weiss, 1986; Martin and Rubincam, 1996). In the case of LAGEOS this acceleration is of the order of 15% of the direct solar radiation pressure. Therefore, Earth radiation pressure has a non-negligible impact not only on LAGEOS orbits, but also on the SLR-derived terrestrial reference frame. We investigate the impact of the Earth radiation pressure on LAGEOS orbits and on the SLR-derived parameters. Earth radiation pressure has a remarkable impact on the semi-major axes of the LAGEOS satellites, causing a systematic reduction of 1.5 mm. The infrared Earth radiation causes a reduction of about 1.0 mm and the Earth’s reflectivity of 0.5 mm of the LAGEOS’ semi-major axes. The global scale defined by the SLR network is changed by 0.07 ppb, when applying Earth radiation pressure. The resulting station heights differ by 0.5-0.6 mm in the solution with and without Earth radiation pressure. However, when range biases are estimated, the height differences are absorbed by the range biases, and thus, the station heights are not shifted.

Exogenous gonadotropins do not increase the blood-follicular transportation capacity of extra-ovarian hormones such as prolactin and cortisol.

BACKGROUNDS In vitro fertilization involves high dosage gonadotropin stimulation, which apparently has some negative impact on follicular endocrine function. As chorionic gonadotropin stimulation has been shown to increase the blood-follicular permeability in animal models, this raises the question if such an effect also applies to gonadotropins in humans, possibly affecting the endocrine follicular milieu. FINDINGS Follicular fluid and serum were collected at the time of follicular aspiration in in vitro fertilisation without (Natural cycle IVF, n = 24) and with (conventional gonadotropin stimulated IVF, n = 31) gonadotropin stimulation. The concentration of the extra-ovarian hormones prolactin and cortisol were analysed by immunoassays. RESULTS Median serum prolactin and cortisol concentrations were 12.3 ng/mL and 399 nmol/L without versus 32.2 ng/mL and 623 nmol/L with gonadotropin stimulation. The corresponding concentrations in follicular fluid were 20.6 ng/mL and 445 nmol/L versus 28.8 ng/ml and 456 nmol/L for prolactin and cortisol. As a consequence, mean follicular fluid:serum ratios were significantly reduced under gonadotropin stimulation (prolactin p = 0.0138, cortisol p = 0.0001). As an enhanced blood-follicular permeability and transportation, induced by gonadotropin stimulation, would result in increased instead of decreased follicular fluid:serum ratios as found in this study, it can be assumed that this does not affect extra-ovarian protein and steroid hormones as illustrated by prolactin and cortisol. CONCLUSIONS The model of serum follicular fluid:serum ratio of hormones, produced outside the ovaries, did not reveal a gonadotropin induced increased blood-follicular transportation capacity. Therefore it can be assumed that the effect of gonadotropins on follicular endocrine function is not due to an increased ovarian permeability of extra-ovarian hormones.

Das offene Selbstgespräch in Dyaden: Dessen Zusammenhang mit Selbstdarstellungstendenzen und Einfluss auf den Partner

Ausgangslage und Fragestellung In der Forschung zum Selbstgespräch im Sport dominiert die Frage nach dessen Auswir-kungen auf die sprechende Person selber. Gemäss Diaz (1992) besitzt das offene Selbstgespräch aber neben der individuell-regulatorischen auch eine sozial-kommunikative Funktion. Diese sozial-kommunikative Funktion und der damit verbunde-ne Einfluss des Selbstgesprächs auf Beobachter wurden in der Sportwissenschaft bisher nur marginal untersucht (z.B. Gould & Weiss, 1981; Van Raalte, Brewer, Cornelius & Pe-titpas, 2006). Im angestrebten Forschungsvorhaben sollen zwei Fragen geklärt werden: Steht das of-fene, während dem Wettkampf geäusserte Selbstgespräch eines Athleten in Zusammen-hang mit dessen Selbstdarstellung? Beeinflusst das offene Selbstgespräch eines Athle-ten den Dyadenpartner und wie sie sich gegenseitig wahrnehmen? Methode Es werden Doppelpartien im Badminton per Videokamera aufgezeichnet. Mittels einer Korrelationsanalyse soll überprüft werden, ob die so erhobenen Selbstgesprächsaussa-gen mit dem Persönlichkeitsmerkmal „Selbstdarstellung“ der Probanden zusammenhän-gen. Nach Spielschluss werden die Probanden entsprechend eines video-stimulierten Fremdkonfrontationsinterviews mit Spielausschnitten konfrontiert, die offenes Selbstge-spräch ihres Dyadenpartners enthalten. Sie werden dabei nach ihren Kognitionen sowie Emotionen gefragt, die sie während der entsprechenden Spielsituation erlebten. Aktuelle Fragen Welcher Fragebogen zur Erhebung des Persönlichkeitsmerkmals „Selbstdarstellung“ soll Verwendung finden? Zur Auswahl steht ein noch zu übersetzender, validierter, engli-scher und sportspezifischer Fragebogen und die Verwendung eines deutschen Frage-bogens, der habituelle Selbstdarstellungstechniken im Allgemeinen erhebt. Wie soll beim video-stimulierten Fremdkonfrontationsinterview vorgegangen werden? Werden den Probanden z.B. das ganze Spiel oder nur ausgewählte Ausschnitte gezeigt, in denen offenes Selbstgespräch vorkommt? Wie zeitnah muss das Interview durchge-führt werden? Literatur Diaz, R. M. (1992). Methodological Concerns in the Study of Private Speech. In R. M. Diaz & L. E. Berk (Eds.), Private speech. From social interaction to self-regulation (pp. 55-81). Hillsdale, NJ: Lawrence Erlbaum. Gould, D. & Weiss, M. (1981). The effects of model similarity and model talk on self-efficacy and muscular endurance. Journal of Sport Psychology, 3, 17-29. Van Raalte, J. L., Brewer, B. W., Cornelius, A. E. & Petitpas, A. J. (2006). Self-presentational effects of self-talk on perceptions of tennis players. Hellenic Journal of Psychology, 3, 134-149.