31,577 research outputs found
Radiation-reaction-induced evolution of circular orbits of particles around Kerr Black Holes
It is demonstrated that, in the adiabatic approximation, non-Equatorial
circular orbits of particles in the Kerr metric (i.e. orbits of constant
Boyer-Lindquist radius) remain circular under the influence of gravitational
radiation reaction. A brief discussion is given of conditions for breakdown of
adiabaticity and of whether slightly non-circular orbits are stable against the
growth of eccentricity.Comment: 23 pages. Revtex 3.0. Inquiries to [email protected]
A FOLLOW-UP STUDY OF FIFTY-TWO RICHMOND PUBLIC SCHOOL PUPILS GIVEN PSYCHIATRIC STAFFING DURING THE 1966-1967 SCHOOL YEAR
This research study is a descriptive study of the effectiveness of the psychiatric staffing as determined by a follow-up study of fifty-two Richmond Public School Pupils given such staffing during the l966-67 school year. The review of pertinent literature reveals what others have contributed to the knowledge of the nature and function of the school helping team. The teamwork approach, which involves the efforts of several professions and disciplines working closely together, is seen as the best present method to meet the complex, overlapping needs which have been found to affect students\u27 learning.
As a means of establishing guidelines and limits for this study, five areas of concern were defined. The questions to be answered by this study were:
1. What are the socio-economic backgrounds represented by the sample?
2. Were the recommendations made by the school psychiatrist implemented?
3. Is the overall psychiatric staffing effective according to the improvement in pupils presenting problems and the extent to which the recommendations were carried out?
4. To what extent do the available records contain sufficient information for a follow-up study?
5. What are the attitudes of the key persons responsible for the psychiatric staffing toward the effective operation of these staffings?
The Pupil Personnel Services gave its approval to conduct this study. The sample numbered fifty-two.
The agency requested and it was agreed that no pupil, school, or agency be contacted and that information be obtained only from the files and employees of Pupil Personnel Services. An interview schedule was constructed to elicit information to determine the extent to which the recommendations made during the psychiatric staffing were initiated and carried out. This schedule was applied to the pupil records. Open ended questions were used in interview schedules to gather pertinent information from three key persons responsible for the effective operation of the psychiatric staffing.
The fifty-two pupil cases revealed the pupils to be largely from low income families, mostly males with acting-out behavior problems, and with no significant concentration from any one school. A larger percentage of the recommendations that were initiated involved the use of school resources rather than community resources. In nearly half of the pupil cases the recommendations were completely carried out, with a remaining few being carried out to a lesser extent. The findings suggested that, if the recommendations were carried out, the pupil would show behavior improvement. To a large extent the statements made by the key persons generally reflected that methods of record keeping be improved within the Department of Visiting Teachers; that there be an increase in the number and quality of the visiting teachers, especially for elementary and Junior high school placements; that parents of the pupils given psychiatric staffings become involved in the staffings and be included in the treatment process themselves; and that the visiting teacher exercise more responsibility for follow-up on the pupils given psychiatric staffing
Variable pitch fan system for NASA/Navy research and technology aircraft
Preliminary design of a shaft driven, variable-pitch lift fan and lift-cruise fan was conducted for a V/STOL Research and Technology Aircraft. The lift fan and lift-cruise fan employed a common rotor of 157.5 cm diameter, 1.18 pressure ratio variable-pitch fan designed to operate at a rotor-tip speed of 284 mps. Fan performance maps were prepared and detailed aerodynamic characteristics were established. Cost/weight/risk trade studies were conducted for the blade and fan case. Structural sizing was conducted for major components and weights determined for both the lift and lift-cruise fans
Parallel Maximum Clique Algorithms with Applications to Network Analysis and Storage
We propose a fast, parallel maximum clique algorithm for large sparse graphs
that is designed to exploit characteristics of social and information networks.
The method exhibits a roughly linear runtime scaling over real-world networks
ranging from 1000 to 100 million nodes. In a test on a social network with 1.8
billion edges, the algorithm finds the largest clique in about 20 minutes. Our
method employs a branch and bound strategy with novel and aggressive pruning
techniques. For instance, we use the core number of a vertex in combination
with a good heuristic clique finder to efficiently remove the vast majority of
the search space. In addition, we parallelize the exploration of the search
tree. During the search, processes immediately communicate changes to upper and
lower bounds on the size of maximum clique, which occasionally results in a
super-linear speedup because vertices with large search spaces can be pruned by
other processes. We apply the algorithm to two problems: to compute temporal
strong components and to compress graphs.Comment: 11 page
Heavy and Light Quarks with Lattice Chiral Fermions
The feasibility of using lattice chiral fermions which are free of
errors for both the heavy and light quarks is examined. The fact that the
effective quark propagators in these fermions have the same form as that in the
continuum with the quark mass being only an additive parameter to a chirally
symmetric antihermitian Dirac operator is highlighted. This implies that there
is no distinction between the heavy and light quarks and no mass dependent
tuning of the action or operators as long as the discretization error is negligible. Using the overlap fermion, we find that the
(and ) errors in the dispersion relations of the pseudoscalar and
vector mesons and the renormalization of the axial-vector current and scalar
density are small. This suggests that the applicable range of may be
extended to with only 5% error, which is a factor of
larger than that of the improved Wilson action. We show that the generalized
Gell-Mann-Oakes-Renner relation with unequal masses can be utilized to
determine the finite errors in the renormalization of the matrix elements
for the heavy-light decay constants and semileptonic decay constants of the B/D
meson.Comment: final version to appear in Int. Jou. Mod. Phys.
Templates for stellar mass black holes falling into supermassive black holes
The spin modulated gravitational wave signals, which we shall call smirches,
emitted by stellar mass black holes tumbling and inspiralling into massive
black holes have extremely complicated shapes. Tracking these signals with the
aid of pattern matching techniques, such as Wiener filtering, is likely to be
computationally an impossible exercise. In this article we propose using a
mixture of optimal and non-optimal methods to create a search hierarchy to ease
the computational burden. Furthermore, by employing the method of principal
components (also known as singular value decomposition) we explicitly
demonstrate that the effective dimensionality of the search parameter space of
smirches is likely to be just three or four, much smaller than what has
hitherto been thought to be about nine or ten. This result, based on a limited
study of the parameter space, should be confirmed by a more exhaustive study
over the parameter space as well as Monte-Carlo simulations to test the
predictions made in this paper.Comment: 12 pages, 4 Tables, 4th LISA symposium, submitted to CQ
The role of the quantum properties of gravitational radiation in the dete ction of gravitational waves
The role that the quantum properties of a gravitational wave could play in
the detection of gravitational radiation is analyzed. It is not only
corroborated that in the current laser-interferometric detectors the resolution
of the experimental apparatus could lie very far from the corresponding quantum
threshold (thus the backreaction effect of the measuring device upon the
gravitational wave is negligible), but it is also suggested that the
consideration of the quantum properties of the wave could entail the definition
of dispersion of the measurement outputs. This dispersion would be a function
not only of the sensitivity of the measuring device, but also of the
interaction time (between measuring device and gravitational radiation) and of
the arm length of the corresponding laser- interferometer. It would have a
minimum limit, and the introduction of the current experimental parameters
insinuates that the dispersion of the existing proposals could lie very far
from this minimum, which means that they would show a very large dispersion.Comment: 19 pages, Latex (use epsfig.sty
- …