The Effect of an 8-Week Tai Chi Exercise Program on Physical Functional Performance in Middle-Aged Women

The purpose of this study was to determine the effectiveness of an 8-week Tai Chi Chih exercise program on physical functional performance (PFP) among women aged 45 to 65 years. A quasi-experimental design with a nonequivalent comparison group was used. Forty-one healthy inactive women were assigned to either an intervention group (n = 19) or a comparison group (n = 19). A 60-min Tai Chi Chih exercise class was conducted twice a week for 8 weeks. PFP was measured at baseline and postintervention using the Continuous Scale Physical Functional Performance–10 (CS-PFP 10). Between-group differences were analyzed using one-way analysis of covariance (ANCOVA). After participating in the 8-week program, intervention group participants showed greater improvement in the CS-PFP measures (p .06). However, the comparison group had little changes. The findings from this study suggest that participation in an 8-week Tai Chi Chih exercise program can improve PFP in healthy, community-dwelling middle-aged women.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Figure rotation of dark halos in CDM simulations

We investigate the figure rotation of dark matter halos identified in Lambda CDM simulations. We find that when strict criteria are used to select suitable halos for study, 5 of the 222 halos identified in our z=0 simulation output undergo coherent figure rotation over a 5h^{-1}Gyr period. We discuss the effects of varying the selection criteria and find that pattern speeds for a much larger fraction of the halos can be measured when the criteria are relaxed. Pattern speeds measured over a 1h^{-1}Gyr period follow a log-normal distribution, centred at Omega_p = 0.25h rad/Gyr with a maximum value of 0.94h rad/Gyr. Over a 5h^{-1}Gyr period, the average pattern speed of a halo is about 0.1h rad/Gyr and the largest pattern speed found is 0.24h rad/Gyr. Less than half of the selected halos showed alignment between their figure rotation axis and minor axis, the exact fraction being somewhat dependent on how one defines a halo. While the pattern speeds observed are lower than those generally thought capable of causing spiral structure, we note that coherent figure rotation is found over very long periods and argue that further simulations would be required before strong conclusions about spiral structure in all galaxies could be drawn. We find no correlation between halo properties such as total mass and the pattern speed.Comment: accepted to MNRAS, 8 page

Constraints on the Clustering, Biasing and Redshift Distribution of Radio Sources

We discuss how different theoretical predictions for the variance $\sigma^2$ of the distribution of radio sources can be matched to measurements from the FIRST survey at different flux limits. The predictions are given by the integration of models for the angular correlation function $w(\theta)$ for three different functional forms of the redshift distribution $N(z)$, different spatial correlation functions and by different evolutions of the bias $b(z)$ with redshift. We also consider the two cases of open and flat Universes. Although the predicted $w(\theta)$ show substantial differences due to differences in the $N(z)$'s, these differences are not significant compared to the uncertainties in the current observations. It turns out that the best fit is provided by models with constant biasing at all times, although the difference between models with epoch-independent bias and models with bias that evolves linearly with redshift is not very large. All models with strong evolution of bias with epoch are ruled out. As a further step we directly calculated $w_{obs}(\theta)$ at 3mJy from the catalogue and matched it with our models for the angular correlation function in the hypothesis that the clustering signal comes from two different populations, namely AGN-powered sources and starbursting galaxies. The results are consistent with a scenario for hierarchical clustering where the fainter starbursting galaxies trace the mass at all epochs, while brighter AGN's are strongly biased, with $b(z)$ evolving linearly with redshift, as suggested by some theories of galaxy formation and evolution.Comment: 14 pages, 12 figures, version to appear on MNRA

GREEN IGUANAS (\u3ci\u3eIGUANA IGUANA\u3c/i\u3e): THE UNINTENDED CONSEQUENCE OF SOUND WILDLIFE MANAGEMENT PRACTICES IN A SOUTH FLORIDA PARK

We examined the demographic response of the Green Iguana (Iguana iguana) to the removal of Raccoons in an urban maritime state park in southern Florida. The rapid growth of iguanas to sexual maturity in an underexploited, if not vacant, niche contributed to the rapid recruitment of a large and growing population during the four and one half years since removal of its limiting predator. We proffer here that at sites where Green Iguanas and high density Raccoons are syntopic, future Raccoon removal programs should be concurrent with an equally concerted effort to remove resident Green Iguanas. In this fashion, by replacing one limiting predator with another, a population explosion can be prevented and an advantage can be maintained in the local control of this exotic species

Role for DNA Methylation in the Regulation of miR-200c and miR-141 Expression in Normal and Cancer Cells

The microRNA-200 family participates in the maintenance of an epithelial phenotype and loss of its expression can result in epithelial to mesenchymal transition (EMT). Furthermore, the loss of expression of miR-200 family members is linked to an aggressive cancer phenotype. Regulation of the miR-200 family expression in normal and cancer cells is not fully understood.Epigenetic mechanisms participate in the control of miR-200c and miR-141 expression in both normal and cancer cells. A CpG island near the predicted mir-200c/mir-141 transcription start site shows a striking correlation between miR-200c and miR-141 expression and DNA methylation in both normal and cancer cells, as determined by MassARRAY technology. The CpG island is unmethylated in human miR-200/miR-141 expressing epithelial cells and in miR-200c/miR-141 positive tumor cells. The CpG island is heavily methylated in human miR-200c/miR-141 negative fibroblasts and miR-200c/miR-141 negative tumor cells. Mouse cells show a similar inverse correlation between DNA methylation and miR-200c expression. Enrichment of permissive histone modifications, H3 acetylation and H3K4 trimethylation, is seen in normal miR-200c/miR-141-positive epithelial cells, as determined by chromatin immunoprecipitation coupled to real-time PCR. In contrast, repressive H3K9 dimethylation marks are present in normal miR-200c/miR-141-negative fibroblasts and miR-200c/miR-141 negative cancer cells and the permissive histone modifications are absent. The epigenetic modifier drug, 5-aza-2′-deoxycytidine, reactivates miR-200c/miR-141 expression showing that epigenetic mechanisms play a functional role in their transcriptional control.We report that DNA methylation plays a role in the normal cell type-specific expression of miR-200c and miR-141 and this role appears evolutionarily conserved, since similar results were obtained in mouse. Aberrant DNA methylation of the miR-200c/141 CpG island is closely linked to their inappropriate silencing in cancer cells. Since the miR-200c cluster plays a significant role in EMT, our results suggest an important role for DNA methylation in the control of phenotypic conversions in normal cells

New Constraint on Open Cold-Dark-Matter Models

We calculate the large-angle cross-correlation between the cosmic-microwave-background (CMB) temperature and the x-ray-background (XRB) intensity expected in an open Universe with cold dark matter (CDM) and a nearly scale-invariant spectrum of adiabatic density perturbations. Results are presented as a function of the nonrelativistic-matter density $\Omega_0$ (in units of the critical density) and the x-ray bias $b_x$ (evaluated at a redshift $z\simeq1$ in evolving-bias models) for both an open Universe and a flat cosmological-constant Universe. Recent experimental upper limits to the amplitude of this cross-correlation provide a new constraint to the $\Omega_0$-$b_x$ parameter space that open-CDM models (and the open-inflation models that produce them) must satisfy.Comment: 4 pages, LaTeX. Revised version contains additional figure that clarifies new constraint. (To appear in PRL.

Luminous Red Galaxies in Simulations: Cosmic Chronometers?

There have been a number of attempts to measure the expansion rate of the universe at high redshift using Luminous Red Galaxies (LRGs) as "chronometers". The method generally assumes that stars in LRGs are all formed at the same time. In this paper, we quantify the uncertainties on the measurement of H(z) which arise when one considers more realistic, extended star formation histories. In selecting galaxies from the Millennium Simulation for this study, we show that using rest-frame criteria significantly improves the homogeneity of the sample and that H(z) can be recovered to within 3% at z~0.42 even when extended star formation histories are considered. We demonstrate explicitly that using Single Stellar Populations to age-date galaxies from the semi-analytical simulations provides insufficient accuracy for this experiment but accurate ages are obtainable if the complex star formation histories extracted from the simulation are used. We note, however, that problems with SSP-fitting might be overestimated since the semi-analytical models tend to over predict the late-time star-formation in LRGs. Finally, we optimize an observational program to carry out this experiment.Comment: 11 pages, 10 figures. Accepted to MNRAS

Leadership Reconsidered: Engaging Higher Education in Social Change

Colleges and universities can provide effective environments for the development of future leaders. This book addresses the application of transformative leadership to higher education, identifies resources to use in the process, and..