Auroral thermosphere temperatures from observations of 6300 A emissions

Doppler temperatures determined from observations of the atomic oxygen OI 6300 A line during March 1984 at the University of Alaska/Fairbanks are presented. Temperatures are obtained from Fabry-Perot Interferometer pressure scans using a Fourier transform smoothing and fitting technique; this technique is presented in detail. The temperatures and the spread in the temperatures are consistent from day to day. On the clear nights of March 10 to 13, the temperatures were 800, 750, 750 and 800 K, respectively, with a spread of + or - 100 K. These temperatures are compared to the MSIS (84) model atmosphere for similar geomagnetic conditions and found to be in general agreement; they are also consistent with results obtained by other investigators

A systematic review of the different calculation methods for measuring jump height during the countermovement and drop jump tests

Background The height obtained during the countermovement jump (CMJ) and drop jump (DJ) tests have been measured by numerous studies using different calculation methods and pieces of equipment. However, the differences in calculation methods and equipment used have resulted in discrepancies in jump height being reported. Objectives The aim of this systematic review was to examine the available literature pertaining to the different calculation methods to estimate the jump height during the CMJ and DJ. Methods A systematic review of the literature was undertaken using the SPORTDiscus, Medline, CINAHL, and PubMed electronic databases, with all articles required to meet specified criteria based on a quality scoring system. Results Twenty-one articles met the inclusion criteria, relating various calculation methods and equipment employed when measuring jump height in either of these two tests. The flight time and jump and reach methods provide practitioners with jump height data in the shortest time, but their accuracy is affected by factors such as: participant conditions or equipment sensitivity. The motion capture systems and the double integration method measure the jump height from the centre of mass height at the initial flat foot standing to the apex of jumping, where the centre of mass displacement generated by the ankle plantarflexion is known. The impulse-momentum and flight time methods could only measure the jump height from the centre of mass height at the instant of take-off to the apex of jumping, thus, providing statistically significantly lower jump height values compared to the former two methods. However, further research is warranted to investigate the reliability of each calculation method when using different equipment settings. Conclusions Our findings indicate that using the impulse-momentum method via a force platform is the most appropriate way for the jump height from the instant of take-off to the apex of jumping to be measured. Alternatively, the double integration method via a force platform is preferred to quantify the jump height from the initial flat foot standing to the apex of jumping

Unilateral vs. bilateral hamstring strength assessments: comparing reliability and inter-limb asymmetries in female soccer players

The aims in the present study were to assess reliability for two unilateral and two bilateral field-based hamstring assessments and compare magnitude, direction and agreement of inter-limb asymmetry between tests and sessions. Twenty-nine female soccer players (age: 21.1±4.5 years; height: 169.7±5.8 cm; body mass: 66.2±6.4 kg) performed three repetitions per leg of unilateral isometric 30° (ISO 30°) and 90° (ISO 90°) knee flexion (KF) tasks, and three repetitions total for a bilateral 90° isometric (kneeling ISO) KF and Nordic hamstring exercise (NHE). Absolute reliability of most methods within- and between-session were acceptable (<10%). Relative reliability within-session demonstrated fair to excellent reliability (ICC≥0.784; lower bound 95%CI ≥0.623). Greater variability in between-session relative reliability was observed during the unilateral tests, demonstrating poor to good (ICC=0.698–0.798; lower bound 95%CI = 0.274–0.638). Bilateral assessments demonstrated similar ranges of poor to excellent (ICC=0.679–0.963; lower bound 95%CI = 0.231–0.790). Agreement between-session for inter-limb asymmetry identification was slight and fair in the unilateral tests, with moderate to substantial agreement demonstrated in the bilateral. Being the most reliable within- and between-sessions, demonstrating substantial agreement in asymmetry between-sessions, the NHE would be most appropriate to identify inter-limb asymmetry and assess chronic changes in hamstring strength

A framework to guide practitioners when selecting metrics during the countermovement and drop jump tests

Researchers and practitioners have highlighted the necessity to monitor jump strategy metrics as well as the commonly reported outcome measures during the countermovement (CMJ) and drop jump (DJ) tests. However, there is a risk of confusion for practitioners, given the vast range of metrics that now seem to be on offer via analysis software when collecting data from force platforms. As such, practitioners may benefit from a framework that can help guide metric selection for commonly used jump tests, which is the primary purpose of this article. To contextualise the proposed framework, we have provided two examples for how this could work: one for the CMJ and one for the DJ, noting that these tests are commonly utilized by practitioners during routine testing across a range of sport performance and clinical settings

Relationship between kinetic and kinematic measures of the countermovement jump and national weightlifting performance

Purpose The association between vertical jump and weightlifting performance have been well established often using discrete performance measures such as jump height or peak power which provides little insight into temporal strategies. The purpose of this investigation was to identify currently unassessed temporal countermovement jump metrics and their reliability and relationship to national weightlifting performance. Methods A total of 42 national weightlifting athletes (n = 30 females and 12 males), were recruited for this study. Countermovement jump was measured using a force plate following a national and international competition. Vertical ground reaction force and time data were analyzed using a custom script where temporal metrics relating to specific phases of the jump were extracted. Snatch, Clean and Jerk and Total weightlifting performance was obtained following each competition. Reliability of jump metrics were determined using coefficient of variation and interclass correlation coefficient. A Spearman’s Rho, non-parametric bivariate correlation was used to determine the relationship between the jump metrics and weightlifting performance. Results From a total of 15 metrics, 13 were deemed reliable, with propulsive impulse showing the greatest level of reliability. Correlational analysis showed strong to very strong (r = 0.676–0.817) relationships between all absolute measures of weightlifting performance and propulsive impulse for both women and men. Conclusion This novel finding suggests that practitioners may wish to use propulsive impulse as it may provide more insight into changes of force capabilities following training. Additionally, it may also be used as a talent identification tool given its strong relationship to performance

DE 1 RIMS operational characteristics

The Retarding Ion Mass Spectrometer (RIMS) on the Dynamics Explorer 1 spacecraft observes both the thermal and superthermal (50 eV) ions of the ionosphere and inner magnetosphere. It is capable of measuring the detailed species distribution function of these ions in many cases. It was equipped with an integral electrometer to permit in-flight calibration of the detector sensitivities and variations thereof. A guide to understanding the RIMS data set is given. The reduction process from count rates to physical quantities is discussed in some detail. The procedure used to establish in-flight calibration is described, and results of a comparison with densities from plasma wave measurements are provided. Finally, a discussion is provided of various anomalies in the data set, including changes of channeltron efficiency with time, spin modulation of the axial sensor heads, apparent potential differences between the sensor heads, and failures of the radial head retarding potential sweep and of the -Z axial head aperture plane bias. Studies of the RIMS data set should be conducted only with a thorough awareness of the material presented here, or in collaboration with one of the scientists actively involved with RIMS data analysis

Household malaria knowledge and its association with bednet ownership in settings without large–scale distribution programs: Evidence from rural Madagascar

Background: Insecticide–treated bednets are effective at preventing malaria. This study focuses on household–level factors that are associated with bednet ownership in a rural area of Madagascar which had not been a recipient of large–scale ITN distribution. Methods: Data were gathered on individual and household characteristics, malaria knowledge, household assets and bednet ownership. Principal components analysis was used to construct both a wealth index based on household assets and a malaria knowledge index based on responses to questions about malaria. Bivariate and multivariate regressions were used to determine predictors of household bednet ownership and malaria knowledge. Results: Forty–seven of 560 households (8.4%) owned a bednet. In multivariate analysis, higher level of malaria knowledge among household members was the only variable significantly associated with bednet ownership (odds ratio 3.72, P < 0.001). Among respondents, predictors of higher malaria knowledge included higher education levels, female sex and reporting fever as the most frequent or dangerous illness in the community. Household wealth was not a significant predictor of bednet ownership or respondent malaria knowledge. Conclusion: In this setting of limited supply of affordable bednets, malaria knowledge was associated with an increased probability of household bednet ownership. Further studies should determine how such malaria knowledge evolves and if malaria–specific education programs could help overcome the barriers to bednet ownership among at–risk households living outside the reach of large–scale bednet distribution programs

A model for two-proton emission induced by electron scattering

A model to study two-proton emission processes induced by electron scattering is developed. The process is induced by one-body electromagnetic operators acting together with short-range correlations, and by two-body $\Delta$ currents. The model includes all the diagrams containing a single correlation function. A test of the sensitivity of the model to the various theoretical inputs is done. An investigation of the relevance of the $\Delta$ currents is done by changing the final state angular momentum, excitation energy and momentum transfer. The sensitivity of the cross section to the details of the correlation function is studied by using realistic and schematic correlations. Results for $^{12}$C, $^{16}$O and $^{40}$Ca nuclei are presented.Comment: 30 pages, 18 figures, 3 table

High Purity Pion Beam at TRIUMF

An extension of the TRIUMF M13 low-energy pion channel designed to suppress positrons based on an energy-loss technique is described. A source of beam channel momentum calibration from the decay pi+ --> e+ nu is also described.Comment: 5 page