ABSTRACT
Gravitational waves are expected to be radiated by supermassive black hole binaries formed during galaxy mergers. A stochastic superposition of gravitational waves from all such binary systems would modulate the arrival times of pulses from radio pulsars. Using observations of millisecond pulsars obtained with the Parkes radio telescope, we constrained the characteristic amplitude of this background, A(c,yr), to be <1.0 × 10(-15) with 95% confidence. This limit excludes predicted ranges for A(c,yr) from current models with 91 to 99.7% probability. We conclude that binary evolution is either stalled or dramatically accelerated by galactic-center environments and that higher-cadence and shorter-wavelength observations would be more sensitive to gravitational waves.
Subject(s)
Cooperative Behavior , Interprofessional Relations , Nursing , Research Personnel , Group Processes , HumansSubject(s)
Family , Group Processes , Psychological Tests , Adolescent , Adult , Aged , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Male , Middle Aged , Nursing , ResearchSubject(s)
Group Processes , Nursing , Research Personnel , Achievement , Group Structure , Humans , Leadership , ResearchABSTRACT
Many questions about the use of the professional portfolio remain. Is the underlying assumption that registered nurses have prior learning that should be credited by baccalaureate programs acceptable to all faculty and all institutions of higher learning? Will the academic quality of the learning experiences of the registered nurse be enhanced or threatened by the portfolio process? Is the portfolio method appropriate for all nurse students or is it best suited to the experienced professional who is articulate and has clear educational and professional goals? How can questions of reliability and validity be addressed? Will faculty maintain the commitment to an individualized method of assessment in times of decreasing resources and expanding responsibilities?
