Introduction to the Special Issue

We are pleased to bring you the second of two special issues of Educational Considerations comprised of papers presented at the 2012 National Education Finance Conference in San Antonio, Texas

Introduction to the Special Issue

This special issue of Educational Considerations presents a selection of papers from the inaugural National Education Finance Conference held in 2011

Introduction to the Special Issue

We are pleased to bring you the first of two special issues of Educational Considerations comprised of papers presented at the 2012 National Education Finance Conference in San Antonio, Texas

A new break in V(D)J recombination

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31034/1/0000711.pd

Asymmetric Supernovae, Pulsars, Magnetars, and Gamma-Ray Bursts

We outline the possible physical processes, associated timescales, and energetics that could lead to the production of pulsars, jets, asymmetric supernovae, and weak gamma-ray bursts in routine circumstances and to a magnetar and perhaps stronger gamma-ray burst in more extreme circumstances in the collapse of the bare core of a massive star. The production of a LeBlanc-Wilson MHD jet could provide an asymmetric supernova and result in a weak gamma-ray burst when the jet accelerates down the stellar density gradient of a hydrogen-poor photosphere. The matter-dominated jet would be formed promptly, but requires 5 to 10 s to reach the surface of the progenitor of a Type Ib/c supernova. During this time, the newly-born neutron star could contract, spin up, and wind up field lines or turn on an alpha-Omega dynamo. In addition, the light cylinder will contract from a radius large compared to the Alfven radius to a size comparable to that of the neutron star. This will disrupt the structure of any organized dipole field and promote the generation of ultrarelativistic MHD waves (UMHDW) at high density and Large Amplitude Electromagnetic Waves (LAEMW) at low density. The generation of the these waves would be delayed by the cooling time of the neutron star about 5 to 10 seconds, but the propagation time is short so the UMHDW could arrive at the surface at about the same time as the matter jet. In the density gradient of the star and the matter jet, the intense flux of UMHDW and LAEMW could drive shocks, generate pions by proton-proton collision, or create electron/positron pairs depending on the circumstances. The UMHDW and LAEMW could influence the dynamics of the explosion and might also tend to flow out the rotation axis to produce a collimated gamma-ray burst.Comment: 31 pages, LaTeX, revised for referee comments, accepted for ApJ, July 10 issu

Large Torque Variations in Two Soft Gamma Repeaters

We have monitored the pulse frequencies of the two soft gamma repeaters SGR 1806-20 and SGR 1900+14 through the beginning of year 2001 using primarily Rossi X-ray Timing Explorer Proportional Counter Array observations. In both sources, we observe large changes in the spin-down torque up to a factor of ~4, which persist for several months. Using long baseline phase-connected timing solutions as well as the overall frequency histories, we construct torque noise power spectra for each SGR. The power spectrum of each source is very red (power-law slope ~-3.5). The torque noise power levels are consistent with some accreting systems on time scales of ~1 year, yet the full power spectrum is much steeper in frequency than any known accreting source. To the best of our knowledge, torque noise power spectra with a comparably steep frequency dependence have only been seen in young, glitching radio pulsars (e.g. Vela). The observed changes in spin-down rate do not correlate with burst activity, therefore, the physical mechanisms behind each phenomenon are also likely unrelated. Within the context of the magnetar model, seismic activity cannot account for both the bursts and the long-term torque changes unless the seismically active regions are decoupled from one another.Comment: 26 pages, 11 figures included, accepted for publication in ApJ, analysis of torque noise power density spectra is revised from previous version and minor text changes were mad

Elite male Flat jockeys display lower bone density and lower resting metabolic rate than their female counterparts: implications for athlete welfare

To test the hypothesis that daily weight-making is more problematic to health in male compared with female jockeys, we compared the bone-density and resting metabolic rate (RMR) in weight-matched male and female Flat-jockeys. RMR (kcal.kg-1 lean mass) was lower in males compared with females as well as lower bone-density Z-scores at the hip and lumbar spine. Data suggest the lifestyle of male jockeys’ compromise health more severely than females, possibly due to making-weight more frequently

Preserved Grasshopper Fauna Of Knife Point Glacier, Fremont County, Wyoming, U.S.A.

In 1987 and 1988, samples of preserved insects were extracted from the ice of Knife Point Glacier, Fremont County, Wyoming. The glacier lies at an altitude of 3500 m a.s.l. in the Shoshone National Forest, Wind River Range, and is known to contain preserved insects. Although the glacier has undergone extensive recession in the last 50 yr, some insect deposits are still embedded at 20 to 25 cm below the surface and perhaps much deeper. The frozen deposits appear to consist entirely of grasshoppers. A few, virtually intact, specimens and body parts were in a state of preservation that allowed their identification as Spharagemon campestris McNeill and Melanoplus spretus (Walsh) or M. sanguinipes (F.). The majority of the deposits consisted of partial bodies and isolated parts, including, in order of frequency: mandibles, tibiae, tentoria, femora, wings (primarily tegmina), and cingulae/epiphalli. Deposits from various depths and locations on the glacier were radiocarbon dated at 205 + 65 to 450 + 80 yr BP. Although access to the glacier is quite difficult, the insects are better preserved than any glacial deposit documented in recent history. Thus, the state of preservation and age of the frozen deposits would suggest that additional, intensive sampling may be valuable in obtain- ing information on the ecology of grasshoppers prior to European settlement of North America

Preserved Grasshopper Fauna Of Knife Point Glacier, Fremont County, Wyoming, U.S.A.

In 1987 and 1988, samples of preserved insects were extracted from the ice of Knife Point Glacier, Fremont County, Wyoming. The glacier lies at an altitude of 3500 m a.s.l. in the Shoshone National Forest, Wind River Range, and is known to contain preserved insects. Although the glacier has undergone extensive recession in the last 50 yr, some insect deposits are still embedded at 20 to 25 cm below the surface and perhaps much deeper. The frozen deposits appear to consist entirely of grasshoppers. A few, virtually intact, specimens and body parts were in a state of preservation that allowed their identification as Spharagemon campestris McNeill and Melanoplus spretus (Walsh) or M. sanguinipes (F.). The majority of the deposits consisted of partial bodies and isolated parts, including, in order of frequency: mandibles, tibiae, tentoria, femora, wings (primarily tegmina), and cingulae/epiphalli. Deposits from various depths and locations on the glacier were radiocarbon dated at 205 + 65 to 450 + 80 yr BP. Although access to the glacier is quite difficult, the insects are better preserved than any glacial deposit documented in recent history. Thus, the state of preservation and age of the frozen deposits would suggest that additional, intensive sampling may be valuable in obtain- ing information on the ecology of grasshoppers prior to European settlement of North America