Mathematical morphology and applications in automated sunspot detection

This presentation discusses the mathematical morphology and applications in automated sunspot detection

Temporal properties of short and long gamma-ray bursts

A temporal analysis was performed on a sample of 100 bright short GRBs with T90 < 2s from the BATSE Current Catalog along with a similar analysis on 319 long bright GRBs with T90 > 2s from the same catalog. The short GRBs were denoised using a median filter and the long GRBs were denoised using a wavelet method. Both samples were subjected to an automated pulse selection algorithm to objectively determine the effects of neighbouring pulses. The rise times, fall times, FWHM, pulse amplitudes and areas were measured and their frequency distributions are presented. The time intervals between pulses were also measured. The frequency distributions of the pulse properties were found to be similar and consistent with lognormal distributions for both the short and long GRBs. The time intervals between the pulses and the pulse amplitudes of neighbouring pulses were found to be correlated with each other. The same emission mechanism can account for the two sub-classes of GRBs.Comment: 3 pages, 8 figures; Proceedings of "Gamma-Ray Burst and Afterglow Astronomy 2001", Woods Hol

An analysis of prop-fan/airframe aerodynamic integration

An approach to aerodynamic integration of turboprops and airframes, with emphasis placed upon wing mounted installations is addressed. Potential flow analytical techniques were employed to study aerodynamic integration of the prop fan propulsion concept with advanced, subsonic, commercial transport airframes. Three basic configurations were defined and analyzed: wing mounted prop fan at a cruise Mach number of 0.8, wing mounted prop fan in a low speed configuration, and aft mounted prop fan at a cruise Mach number of 0.8

Universal relaxational dynamics of gapped one dimensional models in the quantum sine-Gordon universality class

A semiclassical approach to the low-temperature real time dynamics of generic one-dimensional, gapped models in the sine-Gordon model universality class is developed. Asymptotically exact universal results for correlation functions are obtained in the temperature regime T << Delta, where Delta is the energy gap.Comment: 4 pages, 1 figur

Cardiac Depression Scale: Mokken scaling in heart failure patients

Background: There is a high prevalence of depression in patients with heart failure (HF) that is associated with worsening prognosis. The value of using a reliable and valid instrument to measure depression in this population is therefore essential. We validated the Cardiac Depression Scale (CDS) in heart failure patients using a model of ordinal unidimensional measurement known as Mokken scaling. Findings: We administered in face-to-face interviews the CDS to 603 patients with HF. Data were analysed using Mokken scale analysis. Items of the CDS formed a statistically significant unidimensional Mokken scale of low strength (H&lt;0.40) and high reliability (Rho>0.8). Conclusions: The CDS has a hierarchy of items which can be interpreted in terms of the increasingly serious effects of depression occurring as a result of HF. Identifying an appropriate instrument to measure depression in patients with HF allows for early identification and better medical management. Keywords: Cardiac Depression Scale, Heart failure, Depression, Mokken scalin

A far-infrared study of N/O abundance ratio in galactic H 2 regions

Far-infrared lines of N++ and O++ in several galactic H II regions were measured in an effort to probe the abundance ratio N/O. New measurements are presented for W32 (630.8-0.0), Orion A, and G75.84+0.4. The combination of (N III) 57.3 millimicrons and (O III) 88.4 and 51.8 millimicrons yields measurements of N++/O++ that are largely insensitive to electron temperature, density uncertainties, and to clumping of the ionized gas, due to the similarity of the critical densities for these transitions. In the observed nebulae, N++/O++ should be indicative of N/O, a ratio that is of special importance in nucleosynthesis theory. Measurements are compared with previous measurements of M17 and W51. For nebulae in the solar circle, N++/O++ is greater than the N/O values derived from optical studies of N+/O+ in low ionization zones of the same nebulae. We find that N++/O++ in W43 is significantly higher than for the other H II regions in the sample. Since W43 is located at R = 5 kpc, which is the smallest galactocentric distance in our sample, our data appear consistent with the presence of a negative abundance gradient d(N/O)dR

Coherent destruction of tunneling, dynamic localization and the Landau-Zener formula

We clarify the internal relationship between the coherent destruction of tunneling (CDT) for a two-state model and the dynamic localization (DL) for a one-dimensional tight-binding model, under the periodical driving field. The time-evolution of the tight-binding model is reproduced from that of the two-state model by a mapping of equation of motion onto a set of ${\rm SU}(2)$ operators. It is shown that DL is effectively an infinitely large dimensional representation of the CDT in the ${\rm SU}(2)$ operators. We also show that both of the CDT and the DL can be interpreted as a result of destructive interference in repeated Landau-Zener level-crossings.Comment: 5 pages, no figur