Ion chemistry in interstellar space

The temperature dependence of the bimolecular reactions of Cl(+), HCl(+), CH(+), CH2(+), N(+), NH(+), and NH2(+) reacting with H2 have been investigated. For Cl(+) and HCl(+) rate constants have been determined over the temperature range of 150 to 400 K. Preliminary data have been obtained for the other systems. The Cl(+)/H2 system shows a weak, but significant positive temperature dependence that could be important in interstellar modeling studies. The HCl(+)/H2 system shows a substantial negative temperature dependence with the rate constant approaching the collision rate at low temperatures. The association reaction CH3(+) + HCN yields CH3 HCN(+) has been theoretically modeled using statistical phase space theory. Both radiative and collisional stabilization have been included. The results are compared with experiment with good agreement obtained over wide variations in T and p. This system is potentially important in the mechanism of large molecule synthesis in interstellar space

Characterizing upward lightning with and without a terrestrial gamma-ray flash

We compare two observations of gamma-rays before, during, and after lightning flashes initiated by upward leaders from a tower during low-altitude winter thunderstorms on the western coast of Honshu, Japan. While the two leaders appear similar, one produced a terrestrial gamma-ray flash (TGF) so bright that it paralyzed the gamma-ray detectors while it was occurring, and could be observed only via the weaker flux of neutrons created in its wake, while the other produced no detectable TGF gamma-rays at all. The ratio between the indirectly derived gamma-ray fluence for the TGF and the 95% confidence gamma-ray upper limit for the gamma-ray quiet flash is a factor of $1\times10^7$. With the only two observations of this type providing such dramatically different results -- a TGF probably as bright as those seen from space and a powerful upper limit -- we recognize that weak, sub-luminous TGFs in this situation are probably not common, and we quantify this conclusion. While the gamma-ray quiet flash appeared to have a faster leader and more powerful initial continuous current pulse than the flash that produced a TGF, the TGF-producing flash occurred during a weak gamma-ray "glow", while the gamma-ray quiet flash did not, implying a higher electric field aloft when the TGF was produced. We suggest that the field in the high-field region approached by a leader may be more important for whether a TGF is produced than the characteristics of the leader itself.Comment: 21 pages, 6 figures, accepted for publication by the Journal of Geophysical Research - Atmosphere

Far-UV Emission from Elliptical Galaxies at z=0.55

The restframe UV-to-optical flux ratio, characterizing the ``UV upturn'' phenomenon, is potentially the most sensitive tracer of age in elliptical galaxies; models predict that it may change by orders of magnitude over the course of a few Gyr. In order to trace the evolution of the UV upturn as a function of redshift, we have used the far-UV camera on the Space Telescope Imaging Spectrograph to image the galaxy cluster CL0016+16 at z=0.55. Our 25''x25'' field includes four bright elliptical galaxies, spectroscopically confirmed to be passively evolving cluster members. The weak UV emission from the galaxies in our image demonstrates that the UV upturn is weaker at a lookback time 5.6 Gyr earlier than our own, as compared to measurements of the UV upturn in cluster E and S0 galaxies at z=0 and z=0.375. These images are the first with sufficient depth to demonstrate the fading of the UV upturn expected at moderate redshifts. We discuss these observations and the implications for the formation history of galaxies.Comment: 4 pages, Latex. 2 figures. Uses corrected version of emulateapj.sty and apjfonts.sty (included). Accepted for publication in ApJ Letter

Termination of Electron Acceleration in Thundercloud by Intra/Inter-cloud Discharge

An on-ground observation program for high energy atmospheric phenomena in winter thunderstorms along Japan Sea has been performed via measurements of gamma-ray radiation, atmospheric electric field and low-frequency radio band. On February 11, 2017, the radiation detectors recorded gamma-ray emission lasting for 75 sec. The gamma-ray spectrum extended up to 20 MeV and was reproduced by a cutoff power-law model with a photon index of $1.36^{+0.03}_{-0.04}$, being consistent with a Bremsstrahlung radiation from a thundercloud (as known as a gamma-ray glow and a thunderstorm ground enhancement). Then the gamma-ray glow was abruptly terminated with a nearby lightning discharge. The low-frequency radio monitors, installed $\sim$50 km away from the gamma-ray observation site recorded leader development of an intra/inter-cloud discharge spreading over $\sim$60 km area with a $\sim$300 ms duration. The timing of the gamma-ray termination coincided with the moment when the leader development of the intra/inter-cloud discharge passed 0.7 km horizontally away from the radiation monitors. The intra/inter-cloud discharge started $\sim$15 km away from the gamma-ray observation site. Therefore, the glow was terminated by the leader development, while it did not trigger the lightning discharge in the present case.Comment: 12 pages, 4 figures, accepted for publication in Geophysical Research Letter

Stepping On Fall Prevention Project

Background: Falls are a major problem in the United States among the older adult population and provide opportunity for community outreach via student-led physical therapy projects. Objective: The purpose of this project was to investigate the relationship between fall related outcome measures and questionnaires with the completion of the Stepping On Fall Prevention program along with evaluating the benefits of Physical Therapy student development with participation in service learning projects. Methods: The research quantified the fall risk of 13 participants with assessment of: gait speed (Timed Up and Go), lower extremity strength (30-Second Chair Stand), balance (4-Stage Balance Test), and psychological factors (Stay Independent Questionnaire, Falls Efficacy Scale-International, and Geriatric Depression Scale). Results: Of the functional measures, significant improvements were observed in the Timed up and Go (TUG) (∆1.72s ± 1.66, p=0.003), the 30-second chair stand (∆4.54 ± 4.27, p= 0.002), Stage 4 of the 4-Stage Balance Test (∆3.37s ± 3.26, p= 0.003), and the Stay Independent questionnaire (∆1.77 ± 2.52, p=0.026). Conclusion: Stepping On demonstrated improvements in gait speed, strength, and balance. These improvements allow older adults to improve their overall safety in both their own homes and the community. More research is needed to evaluate the psychological benefits of completing Stepping On. Furthermore, service learning project opportunities should become more of a standard practice across physical therapy programs

The Irie Classroom Toolbox, a universal violence-prevention teacher-training programme, in Jamaican preschools: a single-blind, cluster-randomised controlled trial

BACKGROUND: Violence is a leading global public health problem, and interventions in early childhood are important in the primary prevention of violence. We tested whether the Irie Classroom Toolbox, a violence-prevention teacher-training programme reduced violence against children by teachers and reduced class-wide child aggression in Jamaican preschools (catering to children aged 3-6 years). METHODS: We did a single-blind, cluster-randomised controlled trial in 76 preschools in Kingston and St Andrew, randomly selected, using simple randomisation, from 120 eligible preschools. Inclusion criteria were two to four classes of children; at least ten children per class; and located in an urban area. We randomly assigned preschools (1:1) to either the Irie Classroom Toolbox intervention or waiting-list control that received no intervention, using a computer-generated randomisation sequence by an independent statistician masked to school identity. The Toolbox involved training teachers in classroom behaviour management and promoting child social-emotional competence. All assessors were masked to group assignment. All teachers and classrooms in the selected schools participated in the study. Within each school, we used simple randomisation to randomly select up to 12 children aged 4 years for evaluation of child outcomes. The Toolbox intervention was implemented from August to April the following year. Teacher and classroom measures were done at baseline (the summer school term; ie, May to June), post-intervention (after 8 months of intervention; ie, May to June of the following year), and 1-year follow-up (ie, May to June 2 years later). The primary outcomes were observations of violence against children (including physical violence and psychological aggression) by teachers occurring across one full school day, and class-wide child aggression occurring over five 20-min intervals on another school day, all measured at post-intervention and 1-year follow-up and analysed by intention to treat. This trial is registered with ISRCTN, number ISRCTN11968472. FINDINGS: Between June 22, 2015, and April 29, 2016, (after baseline measurements were completed), we assigned 38 preschools (with 119 teachers) to the Toolbox intervention and 38 preschools (with 110 teachers) to control. 441 children in the intervention schools and 424 in the control schools were included in the evaluation. All schools were included in the post-intervention and follow-up analyses. There were fewer counts of violence against children by teachers in the intervention schools compared with control schools at post-intervention (median counts 3 [IQR 0-11] vs 15 [3-35]; effect size -67·12%, 95% CI -80·71 to -53·52, p<0·0001) and 1-year follow-up (median counts 3 [IQR 0-9] vs 6 [1-16]; effect size -53·86, 95% CI -71·08 to -36·65, p<0·0001). No differences between groups were found for class-wide child aggression at post-intervention (effect size 0·07, 95% CI -0·16 to 0·29, p=0·72) or 1-year follow-up (-0·14, -0·42 to 0·16, p=0·72). INTERPRETATION: In Jamaican preschools, the Irie Classroom Toolbox effectively reduced violence against children by teachers. The Toolbox was designed for use with undertrained teachers working in low-resource settings and should be effective with early childhood practitioners in other LMICs. Additional research is needed to further develop the Toolbox to reduce class-wide child aggression. FUNDING: Medical Research Council, Wellcome Trust, UK Aid, and the National Institute of Health Research

Far-Ultraviolet Emission from Elliptical Galaxies at z=0.33

We present far-ultraviolet (far-UV) images of the rich galaxy cluster ZwCl1358.1+6245, taken with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope (HST). When combined with archival HST observations, our data provide a measurement of the UV-to-optical flux ratio in 8 early-type galaxies at z=0.33. Because the UV flux originates in a population of evolved, hot, horizontal branch (HB) stars, this ratio is potentially one of the most sensitive tracers of age in old populations -- it is expected to fade rapidly with lookback time. We find that the UV emission in these galaxies, at a lookback time of 3.9 Gyr, is significantly weaker than it is in the current epoch, yet similar to that in galaxies at a lookback time of 5.6 Gyr. Taken at face value, these measurements imply different formation epochs for the massive ellipticals in these clusters, but an alternative explanation is a "floor" in the UV emission due to a dispersion in the parameters that govern HB morphology.Comment: 4 pages, Latex. 2 figures. Uses corrected version of emulateapj.sty and apjfonts.sty (included). Accepted for publication in ApJ Letter

Observation of enhanced rate coefficients in the H2+_2^+ + H2_2 →\rightarrow H3+_3^+ + H reaction at low collision energies

The energy dependence of the rate coefficient of the H$_2^+\ + {\rm H}_2 \rightarrow {\rm H}_3^+ + {\rm H}$ reaction has been measured in the range of collision energies between $k_\mathrm{B}\cdot 10$ K and $k_\mathrm{B}\cdot 300$ mK. A clear deviation of the rate coefficient from the value expected on the basis of the classical Langevin-capture behavior has been observed at collision energies below $k_\mathrm{B}\cdot 1$ K, which is attributed to the joint effects of the ion-quadrupole and Coriolis interactions in collisions involving ortho-H$_2$ molecules in the $j = 1$ rotational level, which make up 75% of the population of the neutral H$_2$ molecules in the experiments. The experimental results are compared to very recent predictions by Dashevskaya, Litvin, Nikitin and Troe (J. Chem. Phys., in press), with which they are in agreement.Comment: 14 pages, 3 figure

Cruise: YR130612, Stations: S5127- S5138, York River Estuary and Pamunkey River, Virginia, MUDBED Longitudinal Profiler Station Survey bracketing a Flood Tide.

Dataset consists of profile and water column burst Data collected as part of a longitudinal profiler station survey at approximately 20 km, 25 km, 35 km, 45 km, 56 km and 62 km upriver from the mouth of the York River Estuary