Poorly connected groups

We investigate groups whose Cayley graphs have poor\-ly connected subgraphs. We prove that a finitely generated group has bounded separation in the sense of Benjamini--Schramm--Tim\'ar if and only if it is virtually free. We then prove a gap theorem for connectivity of finitely presented groups, and prove that there is no comparable theorem for all finitely generated groups. Finally, we formulate a connectivity version of the conjecture that every group of type $F$ with no Baumslag-Solitar subgroup is hyperbolic, and prove it for groups with at most quadratic Dehn function.Comment: 14 pages. Changes to v2: Proof of the Theorem 1.2 shortened, Theorem 1.4 added completing the no-gap result outlined in v

Poincar\'e profiles of groups and spaces

We introduce a spectrum of monotone coarse invariants for metric measure spaces called Poincar\'{e} profiles. The two extremes of this spectrum determine the growth of the space, and the separation profile as defined by Benjamini--Schramm--Tim\'{a}r. In this paper we focus on properties of the Poincar\'{e} profiles of groups with polynomial growth, and of hyperbolic spaces, where we deduce a connection between these profiles and conformal dimension. As applications, we use these invariants to show the non-existence of coarse embeddings in a variety of examples.Comment: 55 pages. To appear in Revista Matem\'atica Iberoamerican

Poincar\'e profiles of Lie groups and a coarse geometric dichotomy

Poincar\'e profiles are a family of analytically defined coarse invariants, which can be used as obstructions to the existence of coarse embeddings between metric spaces. In this paper we calculate the Poincar\'e profiles of all connected unimodular Lie groups, Baumslag-Solitar groups and Thurston geometries, demonstrating two substantially different types of behaviour. In the case of Lie groups, we obtain a dichotomy which extends both the dichotomy separating rank one and higher rank semisimple Lie groups and the dichotomy separating connected solvable unimodular Lie groups of polynomial and exponential growth. We provide equivalent algebraic, quasi-isometric and coarse geometric formulations of this dichotomy. Our results have many consequences for coarse embeddings, for instance we deduce that for groups of the form $N\times S$, where $N$ is a connected nilpotent Lie group, and $S$ is a simple Lie group of real rank 1, both the growth exponent of $N$, and the Ahlfors-regular conformal dimension of $S$ are non-decreasing under coarse embeddings. These results are new even in the quasi-isometric setting and give obstructions to quasi-isometric embeddings which in many cases are stronger than those previously obtained by Buyalo-Schroeder.Comment: 49 pages. v2: the paper has been restructured, the main results are the same but have been presented differentl

KINEMATICS AND KINETICS OF THE BENCH PRESS AND BENCH PULL

A comparison of kinematics and kinetics from the upper body musculature in shoulder flexion (bench press) and extension (bench pull) movements were performed across loads of 10-100%1RM. Twelve elite male sailors with extensive strength-training experience participated in the study. 1RM strength and force were greater in the bench press, while velocity and power output were greater for the bench pull across the range of loads. Pmax for both mean and peak power occurred at a significantly (

TEST-RETEST RELIABILITY OF SELECTED ERGOMETER GRINDING PERFORMANCE MEASURES

Reliability of grinding performance on a custom-built ergometer was assessed using 18 highly trained America’s Cup sailors. Sixteen grinding conditions varied by load, deck heel (tilt), and grinding direction (forward or backward) were examined. Performance measures were peak power (W) and external work over five seconds (kJ). Statistics were difference in mean (Mdiff), standard error of measurement (SEM) and intra-class correlation coefficients (ICC). External work (SEM = 1.6-6.9%; ICC = 0.91-0.99) was more reliable than peak power (SEM = 1.3-9.6%; ICC = 0.84-0.99). Performance was more consistent when varied by load than by heel condition, and was most reliable in lighter load conditions. Within heel conditions, downhill-uphill tilt was more reliable than right-left tilt. Grinding direction did not appear to affect performance reliability

Coexpression analysis of large cancer datasets provides insight into the cellular phenotypes of the tumour microenvironment

Background: Biopsies taken from individual tumours exhibit extensive differences in their cellular composition due to the inherent heterogeneity of cancers and vagaries of sample collection. As a result genes expressed in specific cell types, or associated with certain biological processes are detected at widely variable levels across samples in transcriptomic analyses. This heterogeneity also means that the level of expression of genes expressed specifically in a given cell type or process, will vary in line with the number of those cells within samples or activity of the pathway, and will therefore be correlated in their expression.Results: Using a novel 3D network-based approach we have analysed six large human cancer microarray datasets derived from more than 1,000 individuals. Based upon this analysis, and without needing to isolate the individual cells, we have defined a broad spectrum of cell-type and pathway-specific gene signatures present in cancer expression data which were also found to be largely conserved in a number of independent datasets.Conclusions: The conserved signature of the tumour-associated macrophage is shown to be largely-independent of tumour cell type. All stromal cell signatures have some degree of correlation with each other, since they must all be inversely correlated with the tumour component. However, viewed in the context of established tumours, the interactions between stromal components appear to be multifactorial given the level of one component e.g. vasculature, does not correlate tightly with another, such as the macrophage

Virtuelle Welten, das Problem des Fremdpsychischen und die Entwicklung des moralischen Bewusstseins

Paper on the metaphysics of virtual worlds, the problem of other minds, and the origins of ethical behavior

A 12-week community-based physical activity and mindfulness intervention: health outcomes and markers of autonomic nervous system function (Sweet Hearts biokinetics pilot study)

The prevalence of non-communicable diseases (NCDs) has reached epidemic proportions in South Africa, coinciding with high levels of sedentary behaviour, urbanisation and stress. The nexus between stress, physical inactivity and non-communicable diseases may be regulated, in part, by changes in the autonomic nervous system (ANS). ANS function may be measured using a proxy of heart rate variability (HRV). Regular physical activity, controlled breathing and stress reduction have been shown to alter HRV. This paper presents preliminary data from a community-based biokinetics physical activity and mindfulness intervention (Sweet Hearts) on HRV. The study’s findings demonstrated favourable changes in measures of heart rate variability (HRV) – specifically in the low frequency (LF) spectrum that is associated with baroreflex function. The implications of these changes, in terms of health outcomes, along with efforts at addressing scalability and sustainability of community-based health promotion interventions may be important targets for future study