255 research outputs found
INVESTIGATION OF COACH RATINGS OF TECHNIQUE AND FORCE-TIME PROFILES IN ELITE MALE FRONT CRAWL SPRINT SWIMMERS
The purpose of this investigation was to examine the relationship between assisted towing method (ATM) force-time profiles and coach ratings of front crawl technique. Nine elite male swimmers completed the ATM sprint swimming protocol to obtain active drag and propulsion values. Six coaches each rated overall technique from video footage and technique at each of four stroke events (entry, pull, push, and exit) from images captured throughout the ATM trials. Mean coach technique rating scores were then correlated against four performance measures (FINA point score, 100 m performance best time, active drag value and propulsion value). Results demonstrated weak to strong relationships between the ratings and performance variables for each stroke event
Enhancement of Anisotropy due to Fluctuations in Quasi-One-Dimensional Antiferromagnets
It is shown that the observed anisotropy of magnetization at high magnetic
fields in RbMnBr3 , a quasi-one-dimensional antiferromagnet on a distorted
stacked triangular lattice, is due to quantum and thermal fluctuations. These
fluctuations are taken into account in the framework of linear spin-wave theory
in the region of strong magnetic fields. In this region the divergent
one-dimensional integrals are cut off by magnetic field and the bare easy-plane
anisotropy. Logarithmical dependence on the cutoff leads to the "enhancement"
of the anisotropy in magnetization. Comparison between magnetization data and
our theory with parameters obtained from neutron scattering experiments has
been done.Comment: 15 pages + 5 postscript figures available upon request, RevTex
INVESTIGATION OF ATM PROPULSION FORCE-TIME PROFILES USING FUNCTIONAL DATA ANALYSIS ON FRONT CRAWL SPRINT SWIMMERS
The purpose of this investigation was to assess whether characteristics of the Assisted Towing Method (ATM) propulsive force-time profiles can discriminate between elite and sub-elite male sprint swimmers. Eleven elite and seven sub-elite sprint front crawl swimmers completed the ATM protocol to capture propulsion force-time profiles. The second full stroke cycle taken from the median propulsion trial on both the right and left arms were selected and functional data analysis was used to process the trials. Functional principal components analysis (fPCA) results revealed a statistical difference between the elite and sub-elite groups (p > 0.000). Further, within the elite group profiles, a distinctive double peak was found. The double peak profile could suggest a more efficient and effective stroking ratio of active drag and propulsion within the elite group
IMF biases created by binning and unresolved systems
I discuss two of the possible sources of biases in the determination of the
IMF: binning and the existence of unresolved components. The first source is
important for clusters with a small number of stars detected in a given mass
bin while the second one is relevant for all clusters located beyond the
immediate solar neighborhood. For both cases I will present results of
numerical simulations and I will discuss strategies to correct for their
effects. I also present a brief description of a third unrelated bias source.Comment: 6 pages, 10 figures, to appear in "Young massive clusters, initial
conditions and environments", typo in author's name correcte
Dynamics of viscoelastic membranes
We determine both the in-plane and out-of-plane dynamics of viscoelastic
membranes separating two viscous fluids in order to understand microrheological
studies of such membranes. We demonstrate the general viscoelastic signatures
in the dynamics of shear, bending, and compression modes. We also find a
screening of the otherwise two-dimensional character of the response to point
forces due to the presence of solvent. Finally, we show that there is a linear,
hydrodynamic coupling between the in-plane compression modes of the membrane
and the out-of-plane bending modes in the case where the membrane separates two
different fluids or environments
Speckle Interferometry at SOAR in 2020
The results of speckle interferometric observations at the 4.1 m Southern Astrophysical Research Telescope in 2020, as well as earlier unpublished data, are given, totaling 1735 measurements of 1288 resolved pairs and nonresolutions of 1177 targets. We resolved for the first time 59 new pairs or subsystems in known binaries, mostly among nearby dwarf stars. This work continues our long-term speckle program. Its main goal is to monitor orbital motion of close binaries, including members of high-order hierarchies and Hipparcos pairs in the solar neighborhood. We also report observations of 892 members of young moving groups and associations, where we resolved 103 new pairs
The rate of colonization by macro-invertebrates on artificial substrate samplers
The influence of exposure time upon macro-invertebrate colonization on modified Hester-Dendy substrate samplers was investigated over a 60-day period. The duration of exposure affected the number of individuals, taxa and community diversity. The numbers of individuals colonizing the samplers reached a maximum after 39 days and then began to decrease, due to the emergence of adult insects. Coefficients of variation for the four replicate samples retrieved each sampling day fluctuated extensively throughout the study. No tendencies toward increasing or decreasing coefficients of variation were noted with increasing time of sampler exposure. The number of taxa colonizing the samplers increased throughout the study period. The community diversity index was calculated for each sampling day and this function tended to increase throughout the same period. This supports the hypothesis that an exposure period of 6 weeks, as recommended by the United States Environmental Protection Agency, may not always provide adequate opportunity for a truly representative community of macro-invertebrates to colonize multiplate samplers. Many of the taxa were collected in quite substantial proportions after periods of absence or extreme sparseness. This is attributed to the growth of periphyton and the collection of other materials that created food and new habitats suitable for the colonization of new taxa. Investigation of the relationship between ‘equitability’ and length of exposure revealed that equitability did not vary like diversity with increased time of exposure.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72073/1/j.1365-2427.1979.tb01522.x.pd
Companions of Stars: From Other Stars to Brown Dwarfs to Planets: The Discovery of the First Methane Brown Dwarf
The discovery of the first methane brown dwarf provides a framework for
describing the important advances in both fundamental physics and astrophysics
that are due to the study of companions of stars. I present a few highlights of
the history of this subject along with details of the discovery of the brown
dwarf Gliese 229B. The nature of companions of stars is discussed with an
attempt to avoid biases induced by anthropocentric nomenclature. With the newer
types of remote reconnaissance of nearby stars and their systems of companions,
an exciting and perhaps even more profound set of contributions to science is
within reach in the near future. This includes an exploration of the diversity
of planets in the universe and perhaps soon the first solid evidence for
biological activity outside our Solar System.Comment: 31 pages, 13 figure
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