The evolutionary history of the Arabidopsis arenosa complex : diverse tetraploids mask the Western Carpathian center of species and genetic diversity

The Arabidopsis arenosa complex is closely related to the model plant Arabidopsis thaliana. Species and subspecies in the complex are mainly biennial, predominantly outcrossing, herbaceous, and with a distribution range covering most parts of latitudes and the eastern reaches of Europe. In this study we present the first comprehensive evolutionary history of the A. arenosa species complex, covering its natural range, by using chromosome counts, nuclear AFLP data, and a maternally inherited marker from the chloroplast genome [trnL intron (trnL) and trnL/F intergenic spacer (trnL/F-IGS) of tRNALeu and tRNAPhe, respectively]. We unravel the broad-scale cytogeographic and phylogeographic patterns of diploids and tetraploids. Diploid cytotypes were exclusively found on the Balkan Peninsula and in the Carpathians while tetraploid cytotypes were found throughout the remaining distribution range of the A. arenosa complex. Three centers of genetic diversity were identified: the Balkan Peninsula, the Carpathians, and the unglaciated Eastern and Southeastern Alps. All three could have served as long-term refugia during Pleistocene climate oscillations. We hypothesize that the Western Carpathians were and still are the cradle of speciation within the A. arenosa complex due to the high species number and genetic diversity and the concurrence of both cytotypes there

Current Collegiate Experiences of Big-Time, Non-Revenue, NCAA Athletes

Over the past 30 years experiences of collegiate athletes have been a major focus of scholarly research. Through well-known works, student-athletes’ roles and personal development have been cornerstones of this new knowledge base (Adler & Adler, 1991; Lapchick, 1987). However, an understanding of the big-time athlete who also participates in nonrevenue sports1 is grossly under-represented in the literature. Thus, the purpose of this study was to examine the benefits and challenges that athletes in these sports (e.g., tennis, soccer, golf, track and field, etc.) currently experience. Interviews were conducted with 30 collegiate athletes—who were chosen at random from a sample pool of 9,231 athletes around the country—that focused on the types of benefits and the specific challenges that these athletes face while attending college. Results revealed current benefits of being a big-time, nonrevenue college athlete were very heterogeneous with a total of 24 distinct themes mentioned. The most popular of these included: academic benefits, being on a team, learning life skills, improved time management, and tangible benefits such as equipment, facilities, scholarship and travel. Current challenges that athletes face were much more homogenous, as only three lower order themes received more than two responses: missing out on things in college, lack of free time, and being stereotyped. As a whole, most athletes believed the challenges they face were worth the perceived benefits; and thus, big-time, non-revenue athletes do not receive an inferior overall college education experience (Potuto & O’Hanlon, 2007)

Spitzer spectral line mapping of supernova remnants: I. Basic data and principal component analysis

We report the results of spectroscopic mapping observations carried out toward small (1 x 1 arcmin) regions within the supernova remnants W44, W28, IC443, and 3C391 using the Infrared Spectrograph of the Spitzer Space Telescope. These observations, covering the 5.2 - 37 micron spectral region, have led to the detection of a total of 15 fine structure transitions of Ne+, Ne++, Si+, P+, S, S++, Cl+, Fe+, and Fe++; the S(0) - S(7) pure rotational lines of molecular hydrogen; and the R(3) and R(4) transitions of hydrogen deuteride. In addition to these 25 spectral lines, the 6.2, 7.7, 8.6, 11.3 and 12.6 micron PAH emission bands were also observed. Most of the detected line transitions have proven strong enough to map in several sources, providing a comprehensive picture of the relative distribution of the various line emissions observable in the Spitzer/IRS bandpass. A principal component analysis of the spectral line maps reveals that the observed emission lines fall into five distinct groups, each of which may exhibit a distinct spatial distribution: (1) lines of S and H2 (J > 2); (2) the H2 S(0) line; (3) lines of ions with appearance potentials less than 13.6 eV; (4) lines of ions with appearance potentials greater than 13.6 eV, not including S++; (5) lines of S++. Lines of group (1) likely originate in molecular material subject to a slow, nondissociative shock that is driven by the overpressure within the supernova remnant, and lines in groups (3) - (5) are associated primarily with dissociative shock fronts with a range of (larger) shock velocities. The H2 S(0) line shows a low-density diffuse emission component, and - in some sources - a shock-excited component.Comment: 43 pages, including 21 figures. Accepted for publication in Ap

La protection dans les échanges commerciaux : arguments, formes, mesures et applications aux pays de l'Afrique subsaharienne

L'étude apporte un éclairage sur la question du protectionnisme en Afrique, au départ d'un survol des arguments de celui-ci, d'une présentation de ces formes et indicateurs de mesure et enfin d'une application de ces derniers aux pays subsahariens de ce continent. Elle permet de conclure que les pays ne peuvent être véritablement taxés de protectionnisme contrairement à ce qui est souvent avancé. (Résumé d'auteur

Dill extract induces elastic fiber neosynthesis and functional improvement in the ascending aorta of aged mice with reversal of age-dependent cardiac hypertrophy and involvement of lysyl oxidase-like-1

Elastic fibers (90% elastin, 10% fibrillin-rich microfibrils) are synthesized only in early life and adolescence mainly by the vascular smooth muscle cells through the cross-linking of its soluble precursor, tropoelastin. Elastic fibers endow the large elastic arteries with resilience and elasticity. Normal vascular aging is associated with arterial remodeling and stiffening, especially due to the end of production and degradation of elastic fibers, leading to altered cardiovascular function. Several pharmacological treatments stimulate the production of elastin and elastic fibers. In particular, dill extract (DE) has been demonstrated to stimulate elastin production in vitro in dermal equivalent models and in skin fibroblasts to increase lysyl oxidase-like-1 (LOXL-1) gene expression, an enzyme contributing to tropoelastin crosslinking and elastin formation. Here, we have investigated the effects of a chronic treatment (three months) of aged male mice with DE (5% or 10

q-Hypergeometric solutions of q-difference equations

AbstractWe present algorithm qHyper for finding all solutions y(x) of a linear homogeneous q-difference equation, such that y(qx)=r(x)y(x) where r(x) is a rational function of x. Applications include construction of basic hypergeometric series solutions, and definite q-hypergeometric summation in closed form

Not a Student, Not an Athlete, a Person

College athletics can place immense demands on athletes in terms of time commitment, physical conditioning, and pressure to perform. However, one important but less visible dimension affected by participation is one’s identity. College athletes hold multiple identities (Sturm et al., 2011) and these identities are further refined through their experiences (Chang et al., 2018). However, much less is known about athletes’ cognitive awareness of others’ perceptions and how those opinions influence athletes’ sense of self. In the present work, 52 Division I collegiate basketball players took part in a qualitative survey focused on understanding their athletic experience based on interactions with others. Responses revealed that athletes had dichotomous beliefs when addressing their perceptions of self and how they believed others viewed them, primarily based on the influence of sport. Conversely, athletes had more differing thoughts when discussing their aspirations and wishes for their future and often discussed professional goals, personality traits, and connections to others. Taken together, these results corroborate the desire (and need) for athletes to foster identities beyond their sport world (Stokowski et al., 2019) and for those who shape the sport experience to proactively work on behalf of athletes in this domain

The Social-Psychological Implications of a Coaching Change at the Collegiate Level: Perceptions of Athletes

The purpose of this study was to better understand the social-psychological processes and outcomes athletes experience during a head coaching change. The authors conducted semistructured interviews with 47 NCAA Division I athletes, representing 11 different sports at 20 distinct institutions. Following inductive analysis of transcribed interviews, seven higher order themes emerged: emotions, academics, goals, leadership, negative effects, positive effects, and changing culture and structure of the team. According to the perceptions of athletes, results showed that coaches stressed the importance of academics and used goal setting principles with their new team. However, athletes also spoke to deficiencies in leadership and the emotional instability that resulted in a loss of confidence, increased stress, and feeling ignored by the new staff. Thus, open and honest lines of communication need to be formed early with athletes—by multiple athletic personnel—so that individuals have the support system necessary to prevent maladaptive results

Evaluation of binomial double sums involving absolute values

We show that double sums of the form $$\sum_{i,j=-n} ^{n} |i^sj^t(i^k-j^k)^\beta| \binom {2n} {n+i} \binom {2n} {n+j}$$ can always be expressed in terms of a linear combination of just four functions, namely $\binom {4n}{2n}$, ${\binom {2n}n}^2$, $4^n\binom {2n}n$, and $16^n$, with coefficients that are rational in $n$. We provide two different proofs: one is algorithmic and uses the second author's computer algebra package Sigma; the second is based on complex contour integrals. In many instances, these results are extended to double sums of the above form where $\binom {2n}{n+j}$ is replaced by $\binom {2m}{m+j}$ with independent parameter $m$.Comment: AmS-LaTeX, 42 pages; substantial revision: several additional and more general results, see Proposition 11 and Theorems 15-1