A three-sphere swimmer for flagellar synchronization

In a recent letter (Friedrich et al., Phys. Rev. Lett. 109:138102, 2012), a minimal model swimmer was proposed that propels itself at low Reynolds numbers by a revolving motion of a pair of spheres. The motion of the two spheres can synchronize by virtue of a hydrodynamic coupling that depends on the motion of the swimmer, but is rather independent of direct hydrodynamic interactions. This novel synchronization mechanism could account for the synchronization of a pair of flagella, e.g. in the green algae Chlamydomonas. Here, we discuss in detail how swimming and synchronization depend on the geometry of the model swimmer and compute the swimmer design for optimal synchronization. Our analysis highlights the role of broken symmetries for swimming and synchronization.Comment: 25 pages, 4 color figures, provisionally accepted for publication in the New Journal of Physic

A numerical case study on the sensitivity of latent heat-flux and cloudiness to the distribution of land-use

The accomplished case studies focus on the influence of land-use on the distributions of latent heat-fluxes and cloud-water. The numerical case studies were performed with the threedimensional non-hydrostatic Mesoscale-Model GESIMA for different land-use distributions applying always the same initial conditions of a cloudy day in spring with a geostrophic wind of 8 m/s from the west. The cloud-water distributions at different times and at different levels, their temporal development, the daily sums of the domain-averaged latent heat-fluxes and cloud-water mixing ratios were investigated. Even simple initial conditions (no orography, stable atmosphere) and simple pattern in the land-use distributions emphasize that the influence of surface heterogeneity on meteorological processes cannot be neglected. As shown in this case study, land-use distribution influences the distribution and the amount of cloud-water as weil as the latent heat-flux. On the whole, all these processes are very complex and non-linear.Die durchgeführten Sensitivitätsstudien konzentrieren sich auf den Einfluß der Landnutzungsverteilung auf die Flüsse latenter Wärme und das Wolkenwasser. Die numerischen Untersuchungen wurden mit dem dreidimensionalen nicht-hydrostatischen Mesoskalen-Modell GESIMA für verschiedene Landnutzungsmuster unter immer den gleichen meteorologischen Anfangsbedingungen für einen bewölkten Frühlingstag mit einem geostrophischen Wind von 8 m/s durchgeführt. Die Wolkenwasserverteilung zu bestimmten Zeiten und in bestimmten Niveaus, die zeitliche Entwicklung der Wolkenwasserverteilung, die Tagessummen der Gebietsmittelwerte der Flüsse latenter Wärme und des Wolkenwassers werden untersucht. Auch einfache Randbedingungen (keine Orographie, stabile, atmosphärische Bedingungen) und einfache Landnutzungsverteilungsmuster machen deutlich, daß der Einfluß der Heterogenität der Unterlage auf meteorologische Prozesse nicht zu vernachlässigen ist. Sie kann entscheidend die Verteilungen der Flüsse latenter Wärme und des Wolkenwassers beeinflussen. Die damit verbundenen Prozesse sind äußerst komplex und nicht linear

A numerical case study on the sensitivity of the water and energy fluxes to the heterogeneity of the distribution of land use

Numerical experiments assuming land-use distributions of different heterogeneity of wet and dry surfaces were performed on a cloudy day in spring with a calm wind to examine their influences on the domain-averaged fluxes as well as on the distribution of the fluxes within the domain. The results substantiate that, for ]arge heterogeneity, i.e., small patches, the distribution of the patches plays no role in the magnitude of the atmospheric fluxes. For !arger patches, however, the domain-averaged latent heat-fluxes depend appreciably on both the heterogeneity as well as on the fractional coverage by the land-use types. On the average, for heterogeneous conditions, the prevailing land-use type governs the fluxes. Nevertheless, no exact linearity between the fractionally coverage of the two land-use types and the resulting fluxes exists. Discontinuities in the fluxes which lead to the non-linear behaviour of the domain-averaged fluxes occur at the border between two !arger areas of extremely different characteristics, namely, grass (wet, cool) and sand (dry, warm). Three different patterns of behaviour are found for the temporal development of the differences in the domain-averaged fluxes which depend on both the heterogeneity and the pattern of the land use.Numerische Experimente, bei denen unterschiedlich heterogene Landnutzungsverteilungen trockener und feuchte Flächen angenommen werden, wurden für einen wolkigen Schwachwindtag im Frühjahr durchgeführt. Die Ergebnisse belegen, daß bei großer Heterogenität, d.h. kleinen Flächen, deren Anordnung keine Rolle spielt. Bei großen Flächen jedoch hängen die Gebietsmittelwerte der latenten Wärmeflüsse merklich sowohl von der Heterogenität als auch von dem Flächenanteil der Landnutzung ab. Im Mittel beherrscht der vorherrschende Landnutzungstyp die Flüsse. Dennoch ist kein exaktes lineares Verhalten zwischen dem Flächenanteil der Landnutzung und den resultierenden Flüssen vorhanden. Diskontinuitäten in der Verteilung der Flüsse, die letztendlich zu der Nichtlinearität der Gebietsmittelwerte der Flüsse führen, treten an den Grenzen der größeren Flächen unterschiedlicher Oberflächencharakteristika auf, in dieser Studie Gras (feucht, kühl) und Sand (trocken, warm). Drei unterschiedliche Verhaltensweisen im zeitlichen Verlauf der Differenzen der Gebietsmittelwerte der Flüsse wurden gefunden, die vom Muster und der Heterogenität der Landnutzung abhängen

Principle-based structured case discussions: do they foster moral competence in medical students?

BACKGROUND: Recent findings suggest that medical students' moral competence decreases throughout medical school. This pilot study gives preliminary insights into the effects of two educational interventions in ethics classes on moral competence among medical students in Munich, Germany. METHODS: Between 2012 and 2013, medical students were tested using Lind's Moral Competence Test (MCT) prior to and after completing different ethics classes. The experimental group (EG, N = 76) participated in principle-based structured case discussions (PBSCDs) and was compared with a control group with theory-based case discussions (TBCDs) (CG, N = 55). The pre/post C-scores were compared using a Wilcoxon Test, ANOVA and effect-size calculation. RESULTS: The C-score improved by around 3.2 C-points in the EG, and by 0.2 C-points in the CG. The mean C-score difference was not statistically significant for the EG (P = 0.14) or between the two groups (P = 0.34). There was no statistical significance for the teachers' influence (P = 0.54) on C-score. In both groups, students with below-average (M = 29.1) C-scores improved and students with above-average C-scores regressed. The increase of the C-Index was greater in the EG than in the CG. The absolute effect-size of the EG compared with the CG was 3.0 C-points, indicating a relevant effect. CONCLUSION: Teaching ethics with PBSCDs did not provide a statistically significant influence on students' moral competence, compared with TBCDs. Yet, the effect size suggests that PBSCDs may improve moral competence among medical students more effectively. Further research with larger and completely randomized samples is needed to gain definite explanations for the results

Principle-based structured case discussions: do they foster moral competence in medical students?

BACKGROUND: Recent findings suggest that medical students' moral competence decreases throughout medical school. This pilot study gives preliminary insights into the effects of two educational interventions in ethics classes on moral competence among medical students in Munich, Germany. METHODS: Between 2012 and 2013, medical students were tested using Lind's Moral Competence Test (MCT) prior to and after completing different ethics classes. The experimental group (EG, N = 76) participated in principle-based structured case discussions (PBSCDs) and was compared with a control group with theory-based case discussions (TBCDs) (CG, N = 55). The pre/post C-scores were compared using a Wilcoxon Test, ANOVA and effect-size calculation. RESULTS: The C-score improved by around 3.2 C-points in the EG, and by 0.2 C-points in the CG. The mean C-score difference was not statistically significant for the EG (P = 0.14) or between the two groups (P = 0.34). There was no statistical significance for the teachers' influence (P = 0.54) on C-score. In both groups, students with below-average (M = 29.1) C-scores improved and students with above-average C-scores regressed. The increase of the C-Index was greater in the EG than in the CG. The absolute effect-size of the EG compared with the CG was 3.0 C-points, indicating a relevant effect. CONCLUSION: Teaching ethics with PBSCDs did not provide a statistically significant influence on students' moral competence, compared with TBCDs. Yet, the effect size suggests that PBSCDs may improve moral competence among medical students more effectively. Further research with larger and completely randomized samples is needed to gain definite explanations for the results

Psychosocial Long-Term Effects of Young Adult Cancer Survivors: Study Protocol of the Longitudinal AYA-LE Long-Term Effects Study

Background: About 3% of new cancer cases affect young adults aged between 15 and 39 years. The young age, the increasing incidence and the relatively good prognosis of this population lead to the growing importance to investigate the psychosocial long-term and late effects. The aims of the AYA-LE long-term effects study are: first, to assess the temporal course and related factors of life satisfaction and psychological distress of adolescent and young adult (AYA) cancer survivors; and second, to examine a specific topic in each of the yearly surveys in a more differentiated way. Methods: This study represents a continuation of the longitudinal AYA-LE study. The existing sample of AYA cancer patients (t1: N = 577; t2: N = 514; aged between 18 and 39 years at diagnosis; all major tumor entities) was extended by four further survey points (t3: 2018, t4: 2019, t5: 2020, t6: 2021). In addition, a comparison sample of young adults without cancer was collected. We measured longitudinal data for outcomes such as quality of life, psychological distress, and fatigue with standardized questionnaires. Furthermore, each survey point included a different cross-sectional topic (e.g., health behavior, occupational situation, and compliance). Discussion: The AYA-LE long-termeffects study will show the long-termconsequences of cancer in young adulthood. We expect at least complete data of 320 participants to be available after the sixth survey, which will be completed in 2021. This will provide a comprehensive and differentiated understanding of the life situation of young adults with cancer in Germany. The findings of our study enable a continuous improvement of the psychosocial care and specific survivorship programs for young cancer patients