Recruiting and Retaining Teachers in the UK: An Analysis of Graduate Occupation Choice from the 1960s to the 1990s

This paper examines the market for teachers in the UK from 1960 to 1996 using graduate cohort data from 5 separate cohorts. We find that relative wages in teaching compared to alternative professions have a significant impact on the likelihood of graduates choosing to teach, although the impact depends upon the market situation at the time. The wage effect on the supply of teachers is strongest at times of low relative teachers' wages, or following a period of decline in those wages. It is also strongest for those individuals who have more recently graduated.labour supply, teachers, relative wages

Acupuncture's Effects in Treating the Sequelae of Acute and Chronic Spinal Cord Injuries: A Review of Allopathic and Traditional Chinese Medicine Literature

Each year, there are an estimated 12 000 individuals who sustain a spinal cord injury (SCI) in the United States. Improved understanding of the pathophysiology of SCI and its sequelae has over the past 50 years led to the development of medical treatments (especially urologic) that have enhanced short- and long-term survival from these injuries. The prevalence of individuals with SCI in this country is ~250 000 individuals; and beyond the incalculable personal consequences of these devastating neurologic injuries, substantial direct and indirect societal costs result from the sequelae of SCI including paralysis, sensory loss, chronic pain, decubiti and bladder and/or bowel incontinence. The purpose of this treatise is to review the allopathic and traditional Chinese medicine (TCM) literature available through MEDLINE, PubMed and eCAM search engines that discuss the potential uses of acupuncture to treat acute and chronic spinal cord injuries and their sequelae, and present the neurophysiologic mechanisms for acupuncture's beneficial effects. There is evidence that use of electroacupuncture in acute SCI may significantly improve long-term neurologic recovery from these injuries both in terms of motor, sensory and bowel/bladder function with essentially no risk. Acupuncture may even improve neurourologic function in individuals with chronic SCI, and help with management with chronic pain associated with these injuries

Neurogenic Bladder

Congenital anomalies such as meningomyelocele and diseases/damage of the central, peripheral, or autonomic nervous systems may produce neurogenic bladder dysfunction, which untreated can result in progressive renal damage, adverse physical effects including decubiti and urinary tract infections, and psychological and social sequelae related to urinary incontinence. A comprehensive bladder-retraining program that incorporates appropriate education, training, medication, and surgical interventions can mitigate the adverse consequences of neurogenic bladder dysfunction and improve both quantity and quality of life. The goals of bladder retraining for neurogenic bladder dysfunction are prevention of urinary incontinence, urinary tract infections, detrusor overdistension, and progressive upper urinary tract damage due to chronic, excessive detrusor pressures. Understanding the physiology and pathophysiology of micturition is essential to select appropriate pharmacologic and surgical interventions to achieve these goals. Future perspectives on potential pharmacological, surgical, and regenerative medicine options for treating neurogenic bladder dysfunction are also presented

Ubiquitous High Speed Transition Region and Coronal Upflows in the Quiet Sun

We study the line profiles of a range of transition region (TR) emission lines observed in typical quiet Sun regions. In magnetic network regions, the Si IV 1402\AA{}, C IV 1548\AA{}, N V 1238\AA{}, O VI 1031\AA{}, and Ne VIII 770\AA{} spectral lines show significant asymmetry in the blue wing of the emission line profiles. We interpret these high-velocity upflows in the lower and upper TR as the quiet Sun equivalent of the recently discovered upflows in the low corona above plage regions (Hara et al., 2008). The latter have been shown to be directly associated with high-velocity chromospheric spicules that are (partially) heated to coronal temperatures and play a significant role in supplying the active region corona with hot plasma (DePontieu et al., 2009}. We show that a similar process likely dominates the quiet Sun network. We provide a new interpretation of the observed quiet Sun TR emission in terms of the relentless mass transport between the chromosphere and corona - a mixture of emission from dynamic episodic heating and mass injection into the corona as well as that from the previously filled, slowly cooling, coronal plasma. Analysis of the observed upflow component shows that it carries enough hot plasma to play a significant role in the energy and mass balance of the quiet corona. We determine the temperature dependence of the upflow velocities to constrain the acceleration and heating mechanism that drives these upflows. We also show that the temporal characteristics of these upflows suggest an episodic driver that sometimes leads to quasi-periodic signals. We suggest that at least some of the quasi-periodicities observed with coronal imagers and spectrographs that have previously been interpreted as propagating magnetoacoustic waves, may instead be caused by these upflows.Comment: 10 pages, 15 figures. In press ApJ. Higher resolution figures, and movies supporting them, can be found at http://download.hao.ucar.edu/pub/mscott/papers/QS

On The Doppler Velocity of Emission Line Profiles Formed in the "Coronal Contraflow" that is the Chromosphere-Corona Mass Cycle

This analysis begins to explore the complex chromosphere-corona mass cycle using a blend of imaging and spectroscopic diagnostics. Single Gaussian fits to hot emission line profiles (formed above 1MK) at the base of coronal loop structures indicate material blue-shifts of 5-10km/s while cool emission line profiles (formed below 1MK) yield red-shifts of a similar magnitude - indicating, to zeroth order, that a temperature-dependent bifurcating flow exists on coronal structures. Image sequences of the same region reveal weakly emitting upward propagating disturbances in both hot and cool emission with apparent speeds of 50-150km/s. Spectroscopic observations indicate that these propagating disturbances produce a weak emission component in the blue wing at commensurate speed, but that they contribute only a few percent to the (ensemble) emission line profile in a single spatio-temporal resolution element. Subsequent analysis of imaging data shows material "draining" slowly (~10km/s) out of the corona, but only in the cooler passbands. We interpret the draining as the return-flow of coronal material at the end of the complex chromosphere-corona mass cycle. Further, we suggest that the efficient radiative cooling of the draining material produces a significant contribution to the red wing of cool emission lines that is ultimately responsible for their systematic red-shift as derived from a single Gaussian fit when compared to those formed in hotter (conductively dominated) domains. The presence of counter-streaming flows complicates the line profiles, their interpretation, and asymmetry diagnoses, but allows a different physical picture of the lower corona to develop.Comment: 7 pages, 5 color figures. Accepted to Appear Ap

On red shifs in the transition region and corona

We present evidence that transition region red-shifts are naturally produced in episodically heated models where the average volumetric heating scale height lies between that of the chromospheric pressure scale height of 200 km and the coronal scale height of 50 Mm. In order to do so we present results from 3d MHD models spanning the upper convection zone up to the corona, 15 Mm above the photosphere. Transition region and coronal heating in these models is due both the stressing of the magnetic field by photospheric and convection `zone dynamics, but also in some models by the injection of emerging magnetic flux.Comment: 8 pages, 9 figures, NSO Workshop #25 Chromospheric Structure and Dynamic

Quasi-periodic Propagating Signals in the Solar Corona: The Signature of Magnetoacoustic Waves or High-Velocity Upflows?

Since the discovery of quasi-periodic propagating oscillations with periods of order three to ten minutes in coronal loops with TRACE and EIT (later with EUVI and EIS), they have been almost universally interpreted as evidence for propagating slow-mode magnetoacoustic (MA) waves in the low-beta coronal environment. We show that this interpretation is not unique. We focus instead on the ubiquitous faint upflows, associated with blue asymmetries of spectral line profiles in footpoint regions of coronal loops, and as faint disturbances propagating along coronal loops in EUV/XR imaging timeseries. The two scenarios are difficult to differentiate using only imaging data, but careful analysis of spectral line profiles indicates that faint upflows are likely responsible for some of the observed quasi-periodic oscillatory signals in the corona. We show that EIS measurements of intensity and velocity oscillations in coronal lines (previously interpreted as direct evidence for propagating waves) are actually accompanied by significant oscillations in the line width that are driven by a quasi-periodically varying component of emission in the blue wing of the line. The faint blue-shifted emission component quasi-periodically modulates the peak intensity and line-centroid of a single Gaussian fit to the profile with the same small amplitudes (respectively a few percent of background intensity, and a few km/s) used to infer the presence of MA waves. Our results indicate that a significant fraction of the quasi-periodicities observed with coronal imagers and spectrographs, previously interpreted as propagating MA waves, are caused by these upflows. The different physical cause for coronal oscillations would significantly impact the prospects of successful coronal seismology using propagating disturbances in coronal loops.Comment: To appear Astrophysical Journal. 14 pages, 13 color figures, 4 movies. High resolution figures and online supporting movies are available at http://tinyurl.com/29s7c4

Why Fast Trains Work: An Assessment of a Fast Regional Rail System in Perth, Australia

Perth’s new 72 km long Southern Rail System opened in 2007. With a maximum speed of 137 km/hr and an average speed of almost 90 km/hr this system acts more like a new high speed rail than a suburban rail system, which in Australia typically averages around 40 km/hr for an all-stops services. The Southern Rail Line was very controversial when being planned as the urban areas served are not at all typical of those normally provided with rail but instead were highly car dependent and scattered low density land uses. Nevertheless it has been remarkably successful, carrying over 70,000 people per day (five times the patronage on the express buses it replaced) and has reached the patronage levels predicted for 2021 a decade ahead of time. The reasons for this success are analyzed and include well-designed interchanges, careful integration of bus services, the use of integrated ticketing and fares without transfer penalties and, crucially the high speed of the system when compared to competing car based trips. The Southern Rail Line in effect explodes the current paradigm of transfer penalties, exposing this as a myth. The lessons for transport planning in low density cities are significant, and are explored further in the paper

Persistent Doppler shift oscillations observed with HINODE/EIS in the solar corona: spectroscopic signatures of Alfvenic waves and recurring upflows

Using data obtained by the EUV Imaging Spectrometer (EIS) onboard Hinode, we have per- formed a survey of obvious and persistent (without significant damping) Doppler shift oscillations in the corona. We have found mainly two types of oscillations from February to April in 2007. One type is found at loop footpoint regions, with a dominant period around 10 minutes. They are characterized by coherent behavior of all line parameters (line intensity, Doppler shift, line width and profile asymmetry), apparent blue shift and blueward asymmetry throughout almost the en- tire duration. Such oscillations are likely to be signatures of quasi-periodic upflows (small-scale jets, or coronal counterpart of type-II spicules), which may play an important role in the supply of mass and energy to the hot corona. The other type of oscillation is usually associated with the upper part of loops. They are most clearly seen in the Doppler shift of coronal lines with forma- tion temperatures between one and two million degrees. The global wavelets of these oscillations usually peak sharply around a period in the range of 3-6 minutes. No obvious profile asymmetry is found and the variation of the line width is typically very small. The intensity variation is often less than 2%. These oscillations are more likely to be signatures of kink/Alfven waves rather than flows. In a few cases there seems to be a pi/2 phase shift between the intensity and Doppler shift oscillations, which may suggest the presence of slow mode standing waves according to wave theories. However, we demonstrate that such a phase shift could also be produced by loops moving into and out of a spatial pixel as a result of Alfvenic oscillations. In this scenario, the intensity oscillations associated with Alfvenic waves are caused by loop displacement rather than density change.Comment: 9 figures, accepted by Ap