Gamma-Ray Burst Dust Echoes Revisited: Expectations at Early Times

Gamma-ray burst (GRB) dust echoes were first proposed as an alternative explanation for the supernova-like (SN-like) components to the afterglows of GRB 980326 and GRB 970228. However, the spectroscopic identification of Type Ic SN 2003dh associated with GRB 030329, as well as the identification of SN-like components to the afterglows of other GRBs, appears to have confirmed the GRB/SN paradigm. However, the likely progenitors of Type Ic SNe are Wolf-Rayet WC stars, and late-type WC stars have been observed to be surrounded by dust, at a distance of 10^14 -- 10^15 cm from the star. Consequently, we revisit the possibility of GRB dust echoes, not on a timescale of weeks after the burst but on a timescale of minutes to hours. We find that if the optical flash is sufficiently bright and the jet sufficiently wide, GRB afterglows may be accompanied by chromatic variations on this timescale. From these signatures, such model parameters as the inner radius of the dust distribution, the initial opening angle of the jet, etc., may be deduced. With rapid and regular localizations of GRBs by HETE-2, Integral, and now Swift, and new and improved robotic telescope systems, these early-time GRB dust echoes may soon be detected. We describe one such robotic telescope system, called PROMPT, that the University of North Carolina at Chapel Hill is building at the Cerro Tololo Inter-American Observatory in greater detail.Comment: Accepted to The Astrophysical Journal, 15 pages, 5 figures, LaTe

Polarized Broad H-alpha Emission from the LINER Nucleus of NGC 1052

Optical spectropolarimetry of the nucleus of the LINER NGC 1052, obtained at the Keck Observatory, reveals a rise in polarization in the wings of the H-alpha line profile. The polarization vector of H-alpha is offset by 67 degrees from the parsec-scale radio axis and by 83 degrees from the kiloparsec-scale radio axis, roughly in accord with expectations for scattering within the opening cone of an obscuring torus. The broad component of H-alpha has FWHM ~ 2100 km/s in total flux and FWHM ~ 5000 km/s in polarized light. Scattering by electrons is the mechanism most likely responsible for this broadening, and we find T_e ~ 10^5 K for the scattering medium, similar to values observed in Seyfert 2 nuclei. This is the first detection of a polarized broad emission line in a LINER, demonstrating that unified models of active galactic nuclei are applicable to at least some LINERs.Comment: 6 pages, 2 figures, prepared using the emulateapj style file, accepted for publication in The Astrophysical Journal Letter

BIOMECHANICS OF RUNNING - Electromyographic Analysis of the Hip during Jogging, Running and Sprinting

The patterns of muscle action during human locomotion have been investigated for several decades. Lower extremity electromyographic activity in walking was investigated by Bartholomew and the Prosthetic Research Group at Berkeley in 1953. (1) Others investigated the actions of specific muscles during various leg movements. Basmajian and LeBan et al. (6) examined the electromyographic action of the iliopsoas muscle. These studies have led to the investigation of running. Saito et aI., (10) presented temporal data on the gait cycle of running. James and Brubaker (5) presented a descriptive analysis of running. Other researchers have directed their work toward sprinting: Fenn (4) investigated frictional and kinetic factors in 1930, and Dillman (3) and Ralph Mann (7) used kinetic analysis. Mann and Hagy (9) and Mann et aI. (8) investigated temporal and electromyographic patterns of walking, running and sprinting. This study investigates and describes the electromyographic activity ofthe lower extrJmities and trunk musculature duringjogging, running, and sprinting

Reconciling taxonomy and phylogenetic inference: formalism and algorithms for describing discord and inferring taxonomic roots

Although taxonomy is often used informally to evaluate the results of phylogenetic inference and find the root of phylogenetic trees, algorithmic methods to do so are lacking. In this paper we formalize these procedures and develop algorithms to solve the relevant problems. In particular, we introduce a new algorithm that solves a "subcoloring" problem for expressing the difference between the taxonomy and phylogeny at a given rank. This algorithm improves upon the current best algorithm in terms of asymptotic complexity for the parameter regime of interest; we also describe a branch-and-bound algorithm that saves orders of magnitude in computation on real data sets. We also develop a formalism and an algorithm for rooting phylogenetic trees according to a taxonomy. All of these algorithms are implemented in freely-available software.Comment: Version submitted to Algorithms for Molecular Biology. A number of fixes from previous versio

Investigating diachronic trends in phonological inventories using BDPROTO

Here we present an expanded version of bdproto, a database comprising phonological inventory data from 257 ancient and reconstructed languages. These data were extracted from historical linguistic reconstructions and brought together into a single unified, normalized, accessible, and Unicode-compliant language resource. This dataset is publicly available and we aim to engage language scientists doing research on language change and language evolution. Furthermore, we identify a hitherto undiscussed temporal bias that complicates the simple comparison of ancient and reconstructed languages with present-day languages. Due to the sparsity of the data and the absence of statistical and computational methods that can adequately handle this bias, we instead directly target rates of change within and across families, thereby providing a case study to highlight bdproto’s research viability; using phylogenetic comparative methods and high-resolution language family trees, we investigate whether consonantal and vocalic systems differ in their rates of change over the last 10,000 years. In light of the compilation of bdproto and the findings of our case study, we discuss the challenges involved in comparing the sound systems of reconstructed languages with modern day languages

‘‘There’s so much more to it than what I initially thought’’: Stepping into researchers’ shoes with a class activity in a first year psychology survey course

In psychology, it is widely agreed that research methods, although central to the discipline, are particularly challenging to learn and teach, particularly at introductory level. This pilot study explored the potential of embedding a student-conducted research activity in a one-semester undergraduate Introduction to Psychology survey course, with the aims of (a) engaging students with the topic of research methods; (b) developing students’ comprehension and application of research methods concepts; and (c) building students’ ability to link research with theory. The research activity explored shoe ownership, examining gender differences and relationships with age, and linking to theories of gender difference and of consumer identity. The process of carrying out the research and reflecting on it created a contextualized, active learning environment in which students themselves raised many issues that research methods lectures seek to cover. Students also wrote richer assignments than standard first year mid-term essay

Random division of an interval

The well-known relation between random division of an interval and the Poisson process is interpreted as a Laplace transformation. With the use of this interpretation a number of (in part known) results is derived very easily