706 research outputs found
The Relationship between NCAA Volleyball Statistics and Team Performance in Womenâs Intercollegiate Volleyball
The purpose of this investigation was to determine relationships among NCAA statistical categories and the success of women\u27s intercollegiate volleyball teams. The investigator used 1994 NCAA box score statistics collected by the NCAA statistics department. These data were entered into a computer and analyzed using sub-programs from SPSSX. Means and standard deviations for each match statistic by match record and divisional alignment were run along with correlational coefficients for all statistics and indices of success (points per game, game record, and match record). Multiple regression equations were run to predict success as defined by points per game. Attack percentage was found to be the most important correlate of team success regardless of divisional alignment.
Blocking was also important for Division I and II teams, but serving was more critical to Division III success. The resultant regression equations were able to account for 64-88 percent of the variance in predicting team success across the three divisions. The results demonstrated that success can be predicted to some extent in women\u27s intercollegiate volleyball using NCAA match statistics, but prediction accuracy might be improved by including statistics currently missing from NCAA box scores (eg., passing accuracy)
A Test Of Several Hypotheses For The Determination Of Seed Number In Amelanchier Arborea, Using Simulated Probability Distributions To Evaluate Data
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141472/1/ajb208792.pd
Are we far from testing general relativity with the transiting extrasolar planet HD 209458b `Osiris'?
In this paper we investigate the possibility of measuring the general
relativistic gravitoelectric contribution P^(GE) to the orbital period P of the
transiting exoplanet HD 209458b 'Osiris'. It turns out that the predicted
magnitude of such an effect is \sim 0.1 s, while the most recent determinations
of the orbital period of HD 209458b with the photometric transit method are
accurate to \sim 0.01 s. The present analysis shows that the major limiting
factor is the \sim 1 m s^-1 sensitivity in the measurement of the projected
semiamplitude of the star's radial velocity K. Indeed, it affects the
determination of the mass m of the planet which, in turn, induces a systematic
error in the Keplerian period P^(0) of \sim 8 s. It is of crucial importance
because P^(0) should be subtracted from the measured period in order to extract
the relativistic correction. The present-day uncertainty in does not yet
make necessary the inclusion of relativistic corrections in the data-reduction
process of the determination of the system's parameters. The present situation
could change only if improvements of one-two orders of magnitude in the
ground-based Doppler spectroscopy technique occurred.Comment: LaTex2e, 11 pages, 18 references, no figures, no tables. Section 5
improved. Small corrections. To appear in New Astronom
Forward Modeling of Space-borne Gravitational Wave Detectors
Planning is underway for several space-borne gravitational wave observatories
to be built in the next ten to twenty years. Realistic and efficient forward
modeling will play a key role in the design and operation of these
observatories. Space-borne interferometric gravitational wave detectors operate
very differently from their ground based counterparts. Complex orbital motion,
virtual interferometry, and finite size effects complicate the description of
space-based systems, while nonlinear control systems complicate the description
of ground based systems. Here we explore the forward modeling of space-based
gravitational wave detectors and introduce an adiabatic approximation to the
detector response that significantly extends the range of the standard low
frequency approximation. The adiabatic approximation will aid in the
development of data analysis techniques, and improve the modeling of
astrophysical parameter extraction.Comment: 14 Pages, 14 Figures, RevTex
RECOGNITION OF TAXONOMICALLY SIGNIFICANT CLUSTERS NEAR THE SPECIES LEVEL, USING COMPUTATIONALLY INTENSE METHODS, WITH EXAMPLES FROM THE STEPHANODISCUS NIAGARAE COMPLEX (BACILLARIOPHYCEAE) 1
Since the early 1960s, numerical techniques have produced a wide variety of methods to suggest classifications of organisms based on quantitative measurements. A long-recognized shortcoming of these methods is that they will suggest classifications for any group of organisms and any set of measurements, whether or not the clusters in the suggested classification have any natural meaning or significance. Some progress has been made in assessing the reality of clusters determined by various methods. Data simulated to reflect known cluster structure have been used to test the accuracy of different methods, Various methods have been applied to the same data sets to compare how well they realize various desirable properties. Here we define a data-based model of randomness to represent what might be meant by âno natural basis for subdivision into clustersâ and use it to compare an observed measure of cluster distinctness to the distribution of this measure predicted by this model of randomness. In this way, unwarranted subdivision can be statistically avoided, and significant subdivisions can be investigated with confidence. Our methods are illustrated with some examples from the Stephanodiscus niagarae Ehrenb. species complex. Significant differences in morphologic expression are identified in S. reimerii Theriot and Stoermer in Theriot, S. superiorensis Theriot and Stoermer and S. yellowstonensis Theriot and Stoermer. In addition, statistically significant clusters are identified in S. niagarae populations from different geographic locations and in members of the same population grown in different environments. These results suggest current criteria for resolving diatom taxa may not be sufficient to discern subtle differences that occur between real species.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65691/1/j.0022-3646.1997.01049.x.pd
Conservation laws for vacuum tetrad gravity
Ten conservation laws in useful polynomial form are derived from a Cartan
form and Exterior Differential System (EDS) for the tetrad equations of vacuum
relativity. The Noether construction of conservation laws for well posed EDS is
introduced first, and an illustration given, deriving 15 conservation laws of
the free field Maxwell Equations from symmetries of its EDS. The Maxwell EDS
and tetrad gravity EDS have parallel structures, with their numbers of
dependent variables, numbers of generating 2-forms and generating 3-forms, and
Cartan character tables all in the ratio of 1 to 4. They have 10 corresponding
symmetries with the same Lorentz algebra, and 10 corresponding conservation
laws.Comment: Final version with additional reference
Sensitivity curves for spaceborne gravitational wave interferometers
To determine whether particular sources of gravitational radiation will be
detectable by a specific gravitational wave detector, it is necessary to know
the sensitivity limits of the instrument. These instrumental sensitivities are
often depicted (after averaging over source position and polarization) by
graphing the minimal values of the gravitational wave amplitude detectable by
the instrument versus the frequency of the gravitational wave. This paper
describes in detail how to compute such a sensitivity curve given a set of
specifications for a spaceborne laser interferometer gravitational wave
observatory. Minor errors in the prior literature are corrected, and the first
(mostly) analytic calculation of the gravitational wave transfer function is
presented. Example sensitivity curve calculations are presented for the
proposed LISA interferometer. We find that previous treatments of LISA have
underestimated its sensitivity by a factor of .Comment: 27 pages + 5 figures, REVTeX, accepted for publication in Phys Rev D;
Update reflects referees comments, figure 3 clarified, figure 5 corrected for
LISA baselin
Towards a Singularity-Proof Scheme in Numerical Relativity
Progress in numerical relativity has been hindered for 30 years because of
the difficulties of avoiding spacetime singularities in numerical evolution. We
propose a scheme which excises a region inside an apparent horizon containing
the singularity. Two major ingredients of the scheme are the use of a
horizon-locking coordinate and a finite differencing which respects the causal
structure of the spacetime. Encouraging results of the scheme in the spherical
collapse case are given.Comment: 9 page
Modulator noise suppression in the LISA Time-Delay Interferometric combinations
We previously showed how the measurements of some eighteen time series of
relative frequency or phase shifts could be combined (1) to cancel the phase
noise of the lasers, (2) to cancel the Doppler fluctuations due to non-inertial
motions of the six optical benches, and (3) to remove the phase noise of the
onboard reference oscillators required to track the photodetector fringes, all
the while preserving signals from passinggravitational waves. Here we analyze
the effect of the additional noise due to the optical modulators used for
removing the phase fluctuations of the onboard reference oscillators. We use a
recently measured noise spectrum of an individual modulator to quantify the
contribution of modulator noise to the first and second-generation Time-Delay
Interferometric (TDI) combinations as a function of the modulation frequency.
We show that modulator noise can be made smaller than the expected proof-mass
acceleration and optical-path noises if the modulation frequencies are larger
than MHz in the case of the unequal-arm Michelson TDI combination
, GHz for the Sagnac TDI combination , and
MHz for the symmetrical Sagnac TDI combination . These
modulation frequencies are substantially smaller than previously estimated and
may lead to less stringent requirements on the LISA's oscillator noise
calibration subsystem.Comment: 17 pages, 5 figures. Submitted to: Phys. Rev. D 1
Effects of finite arm-length of LISA on analysis of gravitational waves from MBH binaries
Response of an interferometer becomes complicated for gravitational wave
shorter than the arm-length of the detector, as nature of wave appears
strongly. We have studied how parameter estimation for merging massive black
hole binaries are affected by this complicated effect in the case of LISA. It
is shown that three dimensional positions of some binaries might be determined
much better than the past estimations that use the long wave approximation. For
equal mass binaries this improvement is most prominent at \sim 10^5\sol.Comment: 10 pages, 3 figures, to appear in Phys.Rev.
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