Vanishing largest Lyapunov exponent and Tsallis entropy

We present a geometric argument that explains why some systems having vanishing largest Lyapunov exponent have underlying dynamics aspects of which can be effectively described by the Tsallis entropy. We rely on a comparison of the generalised additivity of the Tsallis entropy versus the ordinary additivity of the BGS entropy. We translate this comparison in metric terms by using an effective hyperbolic metric on the configuration/phase space for the Tsallis entropy versus the Euclidean one in the case of the BGS entropy. Solving the Jacobi equation for such hyperbolic metrics effectively sets the largest Lyapunov exponent computed with respect to the corresponding Euclidean metric to zero. This conclusion is in agreement with all currently known results about systems that have a simple asymptotic behaviour and are described by the Tsallis entropy.Comment: 15 pages, No figures. LaTex2e. Some overlap with arXiv:1104.4869 Additional references and clarifications in this version. To be published in QScience Connec

First Approximation of Population Distributions on the International Space Station

This paper presents an analysis of data derived from thousands of publicly available photographs showing life on the International Space Station (ISS) between 2000 and 2020. Our analysis uses crew and locational information from the photographs’ metadata to identify the distribution of different population groups—by gender, nationality, and space agency affiliation—across modules of the ISS, for the first time. Given the significance of the ISS as the most intensively inhabited space habitat to date, an international cooperative initiative involving 26 countries and five space agencies, and one of the most expensive building projects ever undertaken by humans, developing an understanding of which people are using different parts of the space station is critical for future usage of this and other stations. This study also sheds light on problems faced by future space station designers who are concerned with optimal usage of their habitats. The data from this investigation have been permanently deposited with Open Context. It is freely available for use under a Creative Commons license (CC BY 4.0) at https://doi.org/10.6078/M7668B9H

Automated Identification of Astronauts on Board the International Space Station: A Case Study in Space Archaeology

We develop and apply a deep learning-based computer vision pipeline to automatically identify crew members in archival photographic imagery taken on-board the International Space Station. Our approach is able to quickly tag thousands of images from public and private photo repositories without human supervision with high degrees of accuracy, including photographs where crew faces are partially obscured. Using the results of our pipeline, we carry out a large-scale network analysis of the crew, using the imagery data to provide novel insights into the social interactions among crew during their missions

Crying and feeding problems in infancy and cognitive outcome in preschool children born at risk : a prospective population study

Objective: To investigate whether regulatory problems, i.e., crying and feeding problems in infants > 3 months of age, predict cognitive outcome in preschool children born at risk even when controlled for confounding factors. Methods: A prospective longitudinal study of children born in a geographically defined area in Germany. N = 4427 children of 6705 eligible survivors (66%) participated at all four assessment points (neonatal, 5, 20, and 56 months of age). Excessive crying and feeding problems were measured at 5 months. Mental development was assessed with the Griffiths Scale at 20 months, and cognitive assessments were conducted at 56 months. Neonatal complications, neurological, and psychosocial factors were controlled as confounders in structural equation modeling and analyses of variance. Results: One in five infants suffered from single crying or feeding problems, and 2% had multiple regulatory problems, i.e., combined crying and feeding problems at 5 months. In girls, regulatory problems were directly predictive of lower cognition at 56 months, even when controlled for confounders, whereas in boys, the influence on cognition at 56 months was mediated by low mental development at 20 months. Both in boys and girls, shortened gestational age, neonatal neurological complications, and poor parent-infant relationship were predictive of regulatory problems at 5 months and lower cognition at 56 months. Conclusion: Regulatory problems in infancy have a small but significant adverse effect on cognitive development

Summer thermal structure and anticyclonic circulation of Lake Erie

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95057/1/grl29007.pd

Correlation functions quantify super-resolution images and estimate apparent clustering due to over-counting

We present an analytical method to quantify clustering in super-resolution localization images of static surfaces in two dimensions. The method also describes how over-counting of labeled molecules contributes to apparent self-clustering and how the effective lateral resolution of an image can be determined. This treatment applies to clustering of proteins and lipids in membranes, where there is significant interest in using super-resolution localization techniques to probe membrane heterogeneity. When images are quantified using pair correlation functions, the magnitude of apparent clustering due to over-counting will vary inversely with the surface density of labeled molecules and does not depend on the number of times an average molecule is counted. Over-counting does not yield apparent co-clustering in double label experiments when pair cross-correlation functions are measured. We apply our analytical method to quantify the distribution of the IgE receptor (Fc{\epsilon}RI) on the plasma membranes of chemically fixed RBL-2H3 mast cells from images acquired using stochastic optical reconstruction microscopy (STORM) and scanning electron microscopy (SEM). We find that apparent clustering of labeled IgE bound to Fc{\epsilon}RI detected with both methods arises from over-counting of individual complexes. Thus our results indicate that these receptors are randomly distributed within the resolution and sensitivity limits of these experiments.Comment: 22 pages, 5 figure

A Short Total Synthesis of (±)-Lycorane by a Sequential Intramolecular Acylal Cyclisation (IAC) and Intramolecular Heck Addition Reaction

An intramolecular acylal cyclisation (IAC) approach to the synthesis of a range of bicyclic heterocycles is reported. As an example of the utility of the IAC reaction, the methodology was applied in a protecting-group free five-step total synthesis of (±)-lycorane, incorporating a novel intramolecular Heck addition reaction to generate the pentacyclic core structure of the natural product in good yield

Procoagulant Adaptation of a Blood Coagulation Prothrombinase-like Enzyme Complex in Australian Elapid Venom

The macromolecular enzyme complex prothrombinase serves an indispensable role in blood coagulation as it catalyzes the conversion of prothrombin to thrombin, a key regulatory enzyme in the formation of a blood clot. Interestingly, a virtually identical enzyme complex is found in the venom of some Australian elapid snakes, which is composed of a cofactor factor Va-component and a serine protease factor Xa-like subunit. This review will provide an overview of the identification and characterization of the venom prothrombinase complex and will discuss the rationale for its powerful procoagulant nature responsible for the potent hemostatic toxicity of the elapid venom

3D Printed Polypropylene Continuous-Flow Column Reactors: Exploration of Reactor Utility in SNAr Addition Reactions and the Synthesis of Bicyclic and Tetracyclic Heterocycles

3D printing has the potential to transform the way in which chemical reactions are carried out due to its low-cost, ease-of-use as a technology and its capacity to expedite the development of iteratively enhanced prototypes. In this present study, we developed a novel, low-cost polypropylene (PP) column reactor that was incorporated into an existing continuous-flow reactor for the synthesis of heterocycles. The utility and solvent resistance of the printed devices were explored in SNAr reactions to produce substituted aniline derivatives and in the synthesis of bicyclic and tetracyclic heterocycles. Using this approach, a range of heterocyclic compounds was synthesised including the core structure of the natural product (±)-γ-lycorane and structurally complex compounds based on the tetracyclic core of the erythrina alkaloids

The statistical neuroanatomy of frontal networks in the macaque

We were interested in gaining insight into the functional properties of frontal networks based upon their anatomical inputs. We took a neuroinformatics approach, carrying out maximum likelihood hierarchical cluster analysis on 25 frontal cortical areas based upon their anatomical connections, with 68 input areas representing exterosensory, chemosensory, motor, limbic, and other frontal inputs. The analysis revealed a set of statistically robust clusters. We used these clusters to divide the frontal areas into 5 groups, including ventral-lateral, ventral-medial, dorsal-medial, dorsal-lateral, and caudal-orbital groups. Each of these groups was defined by a unique set of inputs. This organization provides insight into the differential roles of each group of areas and suggests a gradient by which orbital and ventral-medial areas may be responsible for decision-making processes based on emotion and primary reinforcers, and lateral frontal areas are more involved in integrating affective and rational information into a common framework