An Investigation of Parents’ and Children’s Perceptions about Their Participation in a Community-Based Swim Team Program

Why are young swimmers smiling after two hours of intense, daily swim team practices filled with swimming countless laps and focusing on improving their various swimming strokes? What drives parents to willingly transport their children to and from their local YMCAs for swim team practices? Why are swim team participants willing, and even eager, to sit in steamy, hot swimming pool areas and watch or swim in competitive events that last for hours and hours? These are simply a few questions one might have when considering the amount of time, involvement, and commitment required while participating in a community-based YMCA swim team program. This study investigated the perceptions of parents and children about their participation in such a program

Soil carbon pools are affected by species identity and productivity in a tree common garden experiment

The formation and turnover of soil organic carbon (C), the largest terrestrial C pool, is strongly impacted by the ultimate source of that C: leaves, wood, roots, and root exudates. The quantity and quality of these inputs is determined by the identity of the plants involved. Yet substantial uncertainty surrounds the complex relationships among plant traits and soil C, precluding efforts to maximize whole-ecosystem C uptake in nature-based climate mitigation scenarios. In this study, we leveraged a biodiversity-ecosystem function experiment with trees (IDENT) to explore the effects of interspecific variation in plant traits on soil C dynamics in the very early stages of stand development (9 years since planting). Mineral soil C stocks to 5 cm depth were quantified in monospecific plots of 19 tree species planted on a former agricultural field, and analyzed in relation to tree growth and functional traits. We found that tree species identity affected soil bulk density and, to a lesser extent, the carbon content of the topsoil, and thereby total C pools. Among species and across plots, mineral soil C stocks were positively correlated with rates of tree growth and were significantly larger beneath broadleaf trees with “fast” functional traits vs. conifers with more conservative leaf traits, when comparisons were made over equivalent soil depth increments. Thus, plant functional traits mediate interspecific differences in productivity, which in turn influence the magnitude of belowground C stocks. These results highlight important linkages between above- and belowground carbon cycles in the earliest stages of afforestation

Front propagation into unstable and metastable states in Smectic C* liquid crystals: linear and nonlinear marginal stability analysis

We discuss the front propagation in ferroelectric chiral smectics (SmC*) subjected to electric and magnetic fields applied parallel to smectic layers. The reversal of the electric field induces the motion of domain walls or fronts that propagate into either an unstable or a metastable state. In both regimes, the front velocity is calculated exactly. Depending on the field, the speed of a front propagating into the unstable state is given either by the so-called linear marginal stability velocity or by the nonlinear marginal stability expression. The cross-over between these two regimes can be tuned by a magnetic field. The influence of initial conditions on the velocity selection problem can also be studied in such experiments. SmC$^*$ therefore offers a unique opportunity to study different aspects of front propagation in an experimental system

meso-and dl-Bivalvane (Pentasecododecahedrane). Enantiomer Recognition during Reductive Coupling of Racemic and Chiral2,3-Dihydro-and Hexahydrotriquinacen-2-ones

Abstract: Pinacolic reduction of both optically pure and racemic hexahydrotriquinacen-2-one ( 6 ) proceeds with exo,exo carbon-carbon bond formation. Coupling of enantiomerically pure 6 produces diol 11 exclusively. Formation of comparable amounts of 11 and 12 from ( f ) -6 shows that the diastereomeric transition states involved are of comparable energy. Studies with chiral and racemic 2,3-dihydrotriquinacen-2-one (13) gave analogous results. The various 1,2-glycols are identified by their I3C N M R (symmetry is thereby revealed), 'H NMR (shielding of the endo protons at Cj and C3, by hydroxyl is witnessed), and ir spectra, in tandem with the method of synthesis. Conversion of the four diols to their thionocarbonates, and subsequent treatment with triethyl phosphite at the reflux temperature, provides the structurally related olefins stereospecifically. Catalytic hydrogenation of 17 provides dl-bivalvane (2), whereas reduction of 19 gives rise to the meso-bivalvane isomer 3. Other aspects of these transformations and conformational possibilities for 2 and 3 are discussed. The dodecahedron is one of the five perfect solids (the others are the tetrahedron, cube, octahedron, and icosahedron) and consequently has been a source of fascination for mathematicians since the time of Pythagoras and Plato. Only recently, however, has the dodecahedrane molecule attracted the attention of synthetic chemists. Notwithstanding, this (CH)2o polyhedron, which is endowed with most intriguing geometry, remains an unknown Although several approaches to dodecahedrane are currently under investigation in these laboratories, attention is focused specifically herein on the fundamental aspects of that scheme which involves effective "dimerization" of two triquinacene halves. The essence of,this concept is not new, it having been advanced earlier in singular form by Woodward, Fukunaga, and Kelly2 who viewed dodecahedrane as composed of two triquinacene subunits which when properly arranged might be coaxed into sixfold carbon-carbon bond formation as illustrated in 1. That efforts along this . 1 w line have consistently failed is not surprising, for the requirement of a highly ordered transition state which can maintain strict stereochemical control simultaneously (or nearly so) a t 12 trigonal carbon atoms is certain to be overwhelmingly endothermic. Moreover, the added restriction that all six bonds must form from the heavily encumbered endo direction at both termini will surely be most prohibitive. The further need to impinge any given T bond upon lobes of two different noninteracting' double bonds constitutes a process for which chemical analogy is lacking if concerted or metal catalyzedS8 Despite the disadvantages intrinsic to the above model, it is apparent that initial endo,endo coupling of two monomeric triquinacene units at C2 could go far in setting the stage for the ultimate construction of the desired polyhedron. Such a synthetic plan requires that there exist a reaction sequence which can lead readily to 2 as well as to more highly functionalized derivatives of this hydrocarbon. As we have noted earlier,5 a problem immediately presents itself, for the dissymmetry of the necessarily derivatized triquinacene precursors is such that a pair of coupling products having the structural features of 2 and 3 can arise if the monomer 2 3 --is a racemic mixture. Only when bonding between chiral triquinacenes results can it be guaranteed that unwanted formation of "dimer" 3 will be precluded. These conditions presuppose that reductive coupling of racemic triquinacenes will produce diastereomeric products with comparable facility. However, no information is available with which to formulate a reliable prediction. On a promising note, Touboul and Dana have recently reported that electrolytic reduction of racemic 4 proceeds in rigorously enantio-selective fashion with formation of cis-threocis diol 5 to the exclusion of the cis-erythro-cis and other w possible i~o m e r s .~ For the present study where 2,3-dihydrotriquinacen-2-one and its tetrahydro derivative serve as pivotal compounds, the prevailing steric factors are recognized to be generally inimical to bonding from the endo direction.I0 Because adherence to an exo,exo bonding scheme would necessitate ultimate inversion of configuration at C2 in both triquinacene segments, the synthetic methodology of choice should be one which is capable of achieving this transform readily. With these considerations in mind, convenient preparations of 2,3, and several related unsaturated congeners have presently been realized. In structural terms, 2 is recognized to be one of a number of possible pentasecododecahedranes

Immunity toward H1N1 influenza hemagglutinin of historical and contemporary strains suggests protection and vaccine failure

Evolution of H1N1 influenza A outbreaks of the past 100 years is interesting and significantly complex and details of H1N1 genetic drift remains unknown. Here we investigated the clinical characteristics and immune cross-reactivity of significant historical H1N1 strains. We infected ferrets with H1N1 strains from 1943, 1947, 1977, 1986, 1999, and 2009 and showed each produced a unique clinical signature. We found significant cross-reactivity between viruses with similar HA sequences. Interestingly, A/FortMonmouth/1/1947 antisera cross-reacted with A/USSR/90/1977 virus, thought to be a 1947 resurfaced virus. Importantly, our immunological data that didn't show cross-reactivity can be extrapolated to failure of past H1N1 influenza vaccines, ie. 1947, 1986 and 2009. Together, our results help to elucidate H1N1 immuno-genetic alterations that occurred in the past 100 years and immune responses caused by H1N1 evolution. This work will facilitate development of future influenza therapeutics and prophylactics such as influenza vaccines.published_or_final_versio

Nonverbal expression of empathy in healthy human populations : a scoping review protocol

The present scoping review aims to understand the extent and type of evidence related to the nonverbal expression of empathy (and empathic concern) in healthy human (or human-like) empathizers across contexts

Center or Limit Cycle: Renormalization Group as a Probe

Based on our studies done on two-dimensional autonomous systems, forced non-autonomous systems and time-delayed systems, we propose a unified methodology - that uses renormalization group theory - for finding out existence of periodic solutions in a plethora of nonlinear dynamical systems appearing across disciplines. The technique will be shown to have a non-trivial ability of classifying the solutions into limit cycles and periodic orbits surrounding a center. Moreover, the methodology has a definite advantage over linear stability analysis in analyzing centers