Stable Frank-Kasper phases of self-assembled, soft matter spheres

Single molecular species can self-assemble into Frank Kasper (FK) phases, finite approximants of dodecagonal quasicrystals, defying intuitive notions that thermodynamic ground states are maximally symmetric. FK phases are speculated to emerge as the minimal-distortional packings of space-filling spherical domains, but a precise quantitation of this distortion and how it affects assembly thermodynamics remains ambiguous. We use two complementary approaches to demonstrate that the principles driving FK lattice formation in diblock copolymers emerge directly from the strong-stretching theory of spherical domains, in which minimal inter-block area competes with minimal stretching of space-filling chains. The relative stability of FK lattices is studied first using a diblock foam model with unconstrained particle volumes and shapes, which correctly predicts not only the equilibrium {\sigma} lattice, but also the unequal volumes of the equilibrium domains. We then provide a molecular interpretation for these results via self-consistent field theory, illuminating how molecular stiffness regulates the coupling between intra-domain chain configurations and the asymmetry of local packing. These findings shed new light on the role of volume exchange on the formation of distinct FK phases in copolymers, and suggest a paradigm for formation of FK phases in soft matter systems in which unequal domain volumes are selected by the thermodynamic competition between distinct measures of shape asymmetry.Comment: 40 pages, 22 figure

Improving a Family’s Overall Quality of Life Through Parent Training in Pivotal Response Treatment

As the diagnoses of autism in young children continually increase, the need for families to have access to research-based treatment models that are effective and efficient has become clear. Current research demonstrates the demand for parent-delivered behavioral interventions. The aim of this single-case study, conducted as part of an integrated Masters in Education/Special Education Credential Program, was to examine the relationship between one parent trained in pivotal response treatment (PRT), her implementation of PRT techniques, and the correlated gains of behavioral compliance in her 6-year-old boy with high-functioning autism (HFA). Visual analysis of collected data as well as calculation of nonoverlapping data points suggest that a parent, when effectively trained, can utilize PRT to increase the rate of behavioral compliance of his or her own children

Youth Single-Sport Specialization in Professional Baseball Players.

Background: An increasing number of youth baseball athletes are specializing in playing baseball at younger ages. Purpose: The purpose of our study was to describe the age and prevalence of single-sport specialization in a cohort of current professional baseball athletes. In addition, we sought to understand the trends surrounding single-sport specialization in professional baseball players raised within and outside the United States (US). Study Design: Cross-sectional study; Level of evidence, 3. Methods: A survey was distributed to male professional baseball athletes via individual team athletic trainers. Athletes were asked if and at what age they had chosen to specialize in playing baseball at the exclusion of other sports, and data were then collected pertaining to this decision. We analyzed the rate and age of specialization, the reasons for specialization, and the athlete\u27s perception of injuries related to specialization. Results: A total of 1673 professional baseball athletes completed the survey, representing 26 of the 30 Major League Baseball (MLB) organizations. Less than half (44.5%) of professional athletes specialized in playing a single sport during their childhood/adolescence. Those who reported specializing in their youth did so at a mean age of 14.09 ± 2.79 years. MLB players who grew up outside the US specialized at a significantly earlier age than MLB players native to the US (12.30 ± 3.07 vs 14.89 ± 2.24 years, respectively; Conclusion: This study challenges the current trends toward early youth sport specialization, finding that the majority of professional baseball athletes studied did not specialize as youth and that those who did specialize did so at a mean age of 14 years. With the potential cumulative effects of pitching and overhead throwing on an athlete\u27s arm, the trend identified in this study toward earlier specialization within baseball is concerning

Rubin Observatory LSST Transients and Variable Stars Roadmap

The Vera C. Rubin Legacy Survey of Space and Time holds the potential to revolutionize time domain astrophysics, reaching completely unexplored areas of the Universe and mapping variability time scales from minutes to a decade. To prepare to maximize the potential of the Rubin LSST data for the exploration of the transient and variable Universe, one of the four pillars of Rubin LSST science, the Transient and Variable Stars Science Collaboration, one of the eight Rubin LSST Science Collaborations, has identified research areas of interest and requirements, and paths to enable them. While our roadmap is ever-evolving, this document represents a snapshot of our plans and preparatory work in the final years and months leading up to the survey\u27s first light

Approaches for advancing scientific understanding of macrosystems

The emergence of macrosystems ecology (MSE), which focuses on regional- to continental-scale ecological patterns and processes, builds upon a history of long-term and broad-scale studies in ecology. Scientists face the difficulty of integrating the many elements that make up macrosystems, which consist of hierarchical processes at interacting spatial and temporal scales. Researchers must also identify the most relevant scales and variables to be considered, the required data resources, and the appropriate study design to provide the proper inferences. The large volumes of multi-thematic data often associated with macrosystem studies typically require validation, standardization, and assimilation. Finally, analytical approaches need to describe how cross-scale and hierarchical dynamics and interactions relate to macroscale phenomena. Here, we elaborate on some key methodological challenges of MSE research and discuss existing and novel approaches to meet them

Macrosystems ecology: Understanding ecological patterns and processes at continental scales

Macrosystems ecology is the study of diverse ecological phenomena at the scale of regions to continents and their interactions with phenomena at other scales. This emerging subdiscipline addresses ecological questions and environmental problems at these broad scales. Here, we describe this new field, show how it relates to modern ecological study, and highlight opportunities that stem from taking a macrosystems perspective. We present a hierarchical framework for investigating macrosystems at any level of ecological organization and in relation to broader and finer scales. Building on well-established theory and concepts from other subdisciplines of ecology, we identify feedbacks, linkages among distant regions, and interactions that cross scales of space and time as the most likely sources of unexpected and novel behaviors in macrosystems. We present three examples that highlight the importance of this multiscaled systems perspective for understanding the ecology of regions to continents

Discovery of the first symbiotic star in NGC6822

We report the discovery of the first symbiotic star (V=21.6, K_S=15.8 mag) in the Local Group dwarf irregular galaxy NGC6822. This star was identified during a spectral survey of Ha emission-line objects using the Southern African Large Telescope (SALT) during its performance-verification phase. The observed strong emission lines of HI and HeII suggest a high electron density and T* < 130 000 K for the hot companion. The infrared colours allow us to classify this object as an S-type symbiotic star, comprising a red giant losing mass to a compact companion. The red giant is an AGB carbon star, and a semi-regular variable, pulsating in the first overtone with a period of 142 days. Its bolometric magnitude is M_bol=-4.4 mag. We review what is known about the luminosities of extragalactic symbiotic stars, showing that most, possibly all, contain AGB stars. We suggest that a much larger fraction of Galactic symbiotic stars may contain AGB stars than was previously realised.Comment: 6 pages, 4 figures, accepted to MNRA

How low can SUSY go? Matching, monojets and compressed spectra

If supersymmetry (SUSY) has a compressed spectrum then the current mass limits from the LHC can be drastically reduced. We consider a possible 'worst case' scenario where the gluino and/or squarks are degenerate with the lightest SUSY particle (LSP). The most sensitive searches for these compressed spectra are via the final state LSPs recoiling against initial state radiation (ISR). Therefore it is vital that the ISR is understood and possible uncertainties in the predictions are evaluated. We use both MLM (with Pythia 6) and CKKW- L (with Pythia 8) matching and vary matching scales and parton shower properties to accurately determine the theoretical uncertainties in the kinematic distributions. All current LHC SUSY and monojet analyses are employed and we find the most constraining limits come from the CMS Razor and CMS monojet searches. For a scenario of squarks degenerate with the LSP and decoupled gluinos we find $M_{\tilde{q}}>340$ GeV. For gluinos degenerate with the LSP and decoupled squarks, $M_{\tilde{g}}>500$ GeV. For equal mass squarks and gluinos degenerate with the LSP, $M_{\tilde{q},\tilde{g}}>650$ GeV.Comment: References added, version submitted to ep