The 3D structure of the Lagrangian acceleration in turbulent flows

We report experimental results on the three dimensional Lagrangian acceleration in highly turbulent flows. Tracer particles are tracked optically using four silicon strip detectors from high energy physics that provide high temporal and spatial resolution. The components of the acceleration are shown to be statistically dependent. The probability density function (PDF) of the acceleration magnitude is comparable to a log-normal distribution. Assuming isotropy, a log-normal distribution of the magnitude can account for the observed dependency of the components. The time dynamics of the acceleration components is found to be typical of the dissipation scales whereas the magnitude evolves over longer times, possibly close to the integral time scale.Comment: accepted for publication in Physical Review Letter

Ownership-dependent mating tactics of minor males of the beetle Librodor japonicus (Nitidulidae) with intra-sexual dimorphism of mandibles

Intra-sexual dimorphism is found in the weapons of many male beetles. Different behavioral tactics to access females between major and minor males, which adopt fighting and alternative tactics, respectively, are thought to maintain the male dimorphism. In these species major males have enlarged weapons that they use in fights with rival males. Minor males also have small weapons in some of these species, and it is unclear why these males possess weapons. We examined the hypothesis that minor males might adopt a fighting tactic when their status was relatively high in comparison with that of other males (e.g., ownership of a territory). We observed the behavioral tactics of major and minor males of the beetle Librodor japonicus, whose males have a dimorphism of their mandibles. Major males fought for resources, whereas minor males adopted two status-dependent tactics, fighting and sneaking, to access females, depending on their ownership of a sap site. We suggest that ownership status-dependent mating tactics in minor males may maintain the intra-sexual dimorphism in this beetle.</p

Collision Detection and Administration Methods for Many Particles with Different Sizes

This paper deals with the calculation of the motion and the adminis-tration of the contacts for systems with many colliding bodies of round shape and possibly large size-differences. Both two dimensional (2D) and three dimensional (3D) cases are investigated, while the efficiency of the employed algorithms is compared. For the integration of the equations of motion, standard methods are used, but to reduce the effort for collision detection, more sophisticated administration algorithms for the neighbor-hood search are prosented. Especially for large systems with many parti-cles and a wide, polydisperse size distribution, this is a challenge. Three methods, the Verlet-Neighbor List (VL), the Linked Cell (LC) method, and the Linked Linear List (LLL), are discussed and compared for 2D and 3D. Only LLL performs well for strongly different particle sizes

Localized transverse bursts in inclined layer convection

We investigate a novel bursting state in inclined layer thermal convection in which convection rolls exhibit intermittent, localized, transverse bursts. With increasing temperature difference, the bursts increase in duration and number while exhibiting a characteristic wavenumber, magnitude, and size. We propose a mechanism which describes the duration of the observed bursting intervals and compare our results to bursting processes in other systems.Comment: 4 pages, 8 figure

Hyperzographia in Neglect Exposing a Spatial Dissociation between Painting and Writing—A Case Study

The paper depicts and describes the observation of a remarkable post-stroke production of paintings made by a 54-year-old, right-handed man who suffered an acute right hemispheric stroke. The patient’s post-stroke productivity and the spatial distribution of text and drawings were assessed by means of structural analysis of the paintings, as well as neuropsychological and creativity testing. Compared to the age-matched healthy control group, the patient did not only produce more valid answers in the verbal creativity task, but he also drew more images in the figural creativity task. Most strikingly, the painted images were located on the right side in 70% of the paintings, while the text was aligned to the left side in 42% of the paintings. This dissociation between writing and painting behavior was further mirrored in the patient’s neuropsychological performance in a reading test and in a design fluency task. This observation of an increased post-stroke production of paintings may coin a new term, i.e., “hyperzographia”, in analogy to hypergraphia. Additionally, the puzzling dissociation of the writing and painting behavior highlights an important new clinical aspect concerning a differential influence of hemispatial neglect on writing and painting

The prospective relationship between postpartum PTSD and child sleep: A 2-year follow-up study.

The main aim of this study was to examine the prospective impact of maternal postpartum PTSD on several standardized child sleep variables two years postpartum in a large, population-based cohort of mothers. Moreover, we investigated the influence of numerous potential confounding maternal and child factors. Finally, we tested potential reverse temporal associations between child sleep eight weeks postpartum and maternal PTSD symptoms two years postpartum. This study is part of the population-based Akershus Birth Cohort, a prospective cohort study at Akershus University Hospital, Norway. Data from the hospital's birth record, from questionnaires at 17 weeks gestation, eight weeks and two years postpartum were used. At two years postpartum, 39% of the original participants could be retained, resulting in a study population of n = 1480. All child sleep variables significantly correlated with postpartum PTSD symptoms were entered into multiple linear regression analyses, adjusting for confounding factors. Postpartum PTSD symptoms were related to all child sleep variables, except daytime sleep duration. When all significant confounding factors were included into multivariate regression analyses, postpartum PTSD symptoms remained a significant predictor for number and duration of night wakings (β = 0.10 and β = 0.08, respectively), duration of settling time (β = 0.10), and maternal rating of their child's sleep problems (β = 0.12, all p&lt;.01. Child sleep at eight weeks postpartum was not significantly related to maternal sleep two years postpartum when controlling for postpartum PTSD at eight weeks. Child outcomes were based on maternal reporting and might be influenced by maternal mental health. Our results showed for the first time that maternal postpartum PTSD symptoms were prospectively associated with less favorable child sleep, thus increasing the risk of developmental or behavioral problems through an indirect, but treatable pathway. Early detection and treatment of maternal postpartum PTSD may prevent or improve sleep problems and long-term child development

Exact-Exchange Kohn-Sham formalism applied to one-dimensional periodic electronic systems

The Exact-Exchange (EXX) Kohn-Sham formalism, which treats exchange interactions exactly within density-functional theory, is applied to one-dimensional periodic systems. The underlying implementation does not rely on specific symmetries of the considered system and can be applied to any kind of periodic structure in one to three dimensions. As a test system, $trans$-polyacetylene, both in form of an isolated chain and in the bulk geometry has been investigated. Within the EXX scheme, bandstructures and independent particle response functions are calculated and compared to experimental data as well as to data calculated by several other methods. Compared to results from the local-density approximation, the EXX method leads to an increased value for the band gap, in line with similar observations for three-dimensional semiconductors. An inclusion of correlation potentials within the local density approximation or generalized gradient approximations leads to only negligible effects in the bandstructure. The EXX band gaps are in good agreement with experimental data for bulk $trans$-polyacetylene. Packing effects of the chains in bulk $trans$-polyacetylene are found to lower the band gap by about 0.5 eV

The Influence of postpartum posttraumatic Stress Disorders on the childhood Development: a population-based Two-year follow-up Study

Background. Against the background of very limited evidence, the present study aimed to prospectively examine the impact of maternal postpartum PTSD symptoms on four important areas of child development, i.e. gross motor, fine motor, communication, and social-emotional development. Methods. This study is part of the large, population based Akershus Birth Cohort. Data from the hospital’s birth record as well as questionnaire data from 8 weeks and 2 years postpartum were used (n=1,472). The domains of child development that were significantly correlated with PTSD symptoms were entered into regression analyses. Interaction analyses were run to test whether the influence of postpartum PTSD symptoms on child development was moderated by child sex or infant temperament. Results. Postpartum PTSD symptoms had a prospective relationship with poor child social-emotional development two years later. This relationship remained significant even when adjusting for confounders such as maternal depression and anxiety or infant temperament. Both child sex and infant temperament moderated the association between maternal PTSD symptoms and child socialemotional development, i.e. with increasing maternal PTSD symptom load, boys and children with a difficult temperament showed to have comparatively higher levels of social-emotional problems. Conclusions. Examining four different domains of child development, we found a prospective impact of postpartum PTSD symptoms on children’s social-emotional development at two years of age. Our findings suggest that both boys and children with an early difficult temperament may be particularly susceptible to the adverse impact of postpartum PTSD symptoms. Additional studies are needed to further investigate the mechanisms at work

Shaping Robust System through Evolution

Biological functions are generated as a result of developmental dynamics that form phenotypes governed by genotypes. The dynamical system for development is shaped through genetic evolution following natural selection based on the fitness of the phenotype. Here we study how this dynamical system is robust to noise during development and to genetic change by mutation. We adopt a simplified transcription regulation network model to govern gene expression, which gives a fitness function. Through simulations of the network that undergoes mutation and selection, we show that a certain level of noise in gene expression is required for the network to acquire both types of robustness. The results reveal how the noise that cells encounter during development shapes any network's robustness, not only to noise but also to mutations. We also establish a relationship between developmental and mutational robustness through phenotypic variances caused by genetic variation and epigenetic noise. A universal relationship between the two variances is derived, akin to the fluctuation-dissipation relationship known in physics