267 research outputs found
Corrected sidereal anisotropy for underground moons
Data from underground muon telescopes in New Mexico and Bolivia are analyzed in sidereal time and anti-sidereal time in the rigidity range 20 GV to a few 100's of GV. Using both vertical and north- and south- pointing telescopes in both hemispheres, a latitude range of 70 N to 50 S is covered. It is shown that there is an anti-sidereal variation of the P 1 over 2 type, having opposite phase in the Northern and Southern Hemispheres, and maximum amplitude at mid latitudes. The anti-sidereal data are used to correct the sidereal data, using the Nagashima method (Nagashima, 1984); the resulting corrected sidereal vectors for northern hemisphere telescopes have their sidereal maxima close to 3h sidereal time, in reasonable agreement with sidereal data at higher energies from small air showers. The Nagashima correction also eliminates effects due to the reversal of the Sun's polar magnetic field which show up in the uncorrected sidereal data
Cosmic ray intensity and the tilt of the neutral sheet
Recent publications have related long-term variations in cosmic ray intensity at the Earth with long term variations in the tilt of the neutral sheet in the inner heliosphere. The tilt of the neutral sheet from 1971 to 1974 is compared with the cosmic ray intensity at Earth, recorded by the Mt. Washington neutron monitor. The remarkable large decreases in cosmic ray intensity which occurred in 1973 and 1974 correlate well with excursions in the tilt of the neutral sheet which occurred earlier during these same two years
North-south asymmetry in activity on the Sun and cosmic ray density gradients
The marked N-S asymmetry in solar activity (with predominant activity in the Sun's Northern Hemisphere) during the 1960's could certainly account for a S-pointing cosmic ray gradient. It is also clear from the data that the response to this change in solar activity asymmetry, and the related change in the perpendicular cosmic ray density gradient, is different for cosmic ray telescopes in the Earth's Northern and Southern Hemispheres. Northern Hemisphere detectors see a S-pointing gradient in the 60's and a N-pointing gradient after 1971, while Southern Hemisphere telescopes see a S-pointing gradient both before and after the reversal
Enablers and challenges to occupational therapists’ research engagement: A qualitative study
Introduction: To develop occupational therapy’s evidence base and improve its clinical outcomes, occupational therapists must
increase their research involvement. Barriers to research consumption and leadership are well documented, but those relating to
delivering research interventions, less so. Yet, interventions need to be researched within practice to demonstrate their clinical
effectiveness. This study aims to improve understanding of challenges and enablers experienced by occupational therapists who
deliver interventions within research programmes.
Method: Twenty-eight occupational therapists who participated in the Valuing Active Life in Dementia (VALID) research
programme reported their experiences in five focus groups. Data were analysed thematically to identify key and subthemes.
Results: Occupational therapists reported that overwhelming paperwork, use of videos, recruitment and introducing a new
intervention challenged their research involvement, whereas support, protected time and a positive attitude enabled it. The
impact of these challenges and enablers varied between therapists and organisations.
Conclusion: Challenges and enablers to research involvement can be identified but must be addressed within individual and
organisational contexts. Multifaceted collective action to minimise challenges and maximise enablers can facilitate clinicians’
involvement in research. Using this approach should enable occupational therapists to increase their research involvement, thus
demonstrating the clinical effectiveness of their interventions
High‐performance liquid chromatography (HPLC) as a means of assessing the presence of uric acid in archeological human remains:Challenges and future directions
Objectives: This research aimed to replicate the Swinson, D., Snaith, J., Buckberry, J., & Brickley, M. (2010). High performance liquid chromatography (HPLC) in the investigation of gout in paleopathology. International Journal of Osteoarchaeology, 20, 135–143. https://doi.org/10.1002/oa.1009 method for detecting uric acid in archeological human remains to investigate gout in past populations and to improve the original High Performance Liquid Chromatography‐ultraviolet (HPLC‐UV) method by using HPLC‐mass spectrometry (HPLC‐MS), a more sensitive, compound‐specific detection method. Materials and Methods: We used reference samples of uric acid to create a dilution series to assess the limits of quantification and detection. Samples from individuals with and without gout lesions were taken from foot bones and ribs from the English cemeteries of Tanyard, Hickleton, Gloucester, and Lincoln. Results: We could not replicate the results of Swinson and colleagues using HPLC‐UV. Tests using a dilution series of uric acid showed HPLC‐MS was approximately 100× more sensitive than HPLC‐UV, with the additional benefit of being compound specific. A newly developed hydrophilic interaction chromatography (HILIC) method improved retention characteristics. Fourteen samples from eight individuals, five with skeletal lesions consistent with gout, were analyzed with the final method. None showed evidence of uric acid despite the newly developed method's improved sensitivity and specificity. Discussion: The lack of detectable uric acid extracted from these samples suggests that (1) urate crystals were not present in any of the bone samples, regardless of gout status; (2) urate crystals did not survive these specific archeological conditions; or (3) the concentration of uric acid in our bone extracts was low, and thus larger samples would be required
North-South Distribution of Solar Flares during Cycle 23
In this paper, we investigate the spatial distribution of solar flares in the
northern and southern hemisphere of the Sun that occurred during the period
1996 to 2003. This period of investigation includes the ascending phase, the
maximum and part of descending phase of solar cycle 23. It is revealed that the
flare activity during this cycle is low compared to previous solar cycle,
indicating the violation of Gnevyshev-Ohl rule. The distribution of flares with
respect to heliographic latitudes shows a significant asymmetry between
northern and southern hemisphere which is maximum during the minimum phase of
the solar cycle. The present study indicates that the activity dominates the
northern hemisphere in general during the rising phase of the cycle
(1997-2000). The dominance of northern hemisphere is shifted towards the
southern hemisphere after the solar maximum in 2000 and remained there in the
successive years. Although the annual variations in the asymmetry time series
during cycle 23 are quite different from cycle 22, they are comparable to cycle
21.Comment: 6 pages, 2 figures, 1 table; Accepted for the publication in the
proceedings of international solar workshop held at ARIES, Nainital, India on
"Transient Phenomena on the Sun and Interplanetary Medium" in a special issue
of "Journal of Astrophysics and Astronomy (JAA)
Is there an enhancement of muons at sea level from transient events?
In a recent study of a search for enhancements from the galactic center with
muons at sea level using the TUPI muon telescope, we have found several ground
level enhancements (GLEs) as very sharp peaks above the count rate background.
This paper reports a consistent analysis of two GLEs observed in December 2003
and detected after an up-grade of the data acquisition system, which includes a
noise filter and which allows us to verify that the GLEs are not mere
background fluctuations. The main target of this study is a search for the
origin of the GLEs. The results show that one of them has a strong correlation
with a solar flare, while the other has an unknown origin, because there is
neither a satellite report of a solar flare, nor prompt X-ray emission, and nor
a excess of nuclei during the raster scan where the GLE was observed. Even so,
two possibilities are analyzed: the solar flare hypothesis and the gamma ray
burst (GRB) hypothesis. We show, by using the FLUKA Monte Carlo results for
photo-production, that under certain conditions there is the possibility of an
enhancement of muons at sea level from GeV GRBs.Comment: 27 pages, 11 ps figures, Accepted in Astrophysical Journa
DEVELOPMENT OF A FAST MICRON-RESOLUTION BEAM POSITION MONITOR SIGNAL PROCESSOR FOR LINEAR COLLIDER BEAMBASED FEEDBACK SYSTEMS
We present the design of a prototype fast beam position monitor (BPM) signal processor for use in inter-bunch beam-based feedbacks for linear colliders and electron linacs. We describe the FONT4 intra-train beam-based digital position feedback system prototype deployed at the Accelerator test facility (ATF) extraction line at KEK, Japan. The system incorporates a fast analogue beam position monitor front-end signal processor, a digital feedback board, and a fast kicker-driver amplifier. The total feedback system latency is less than 150ns, of which less than 10ns is used for the BPM processor. We report preliminary results of beam tests using electron bunches separated by c. 150ns. Position resolution of order 1 micron was obtained
BEAM TEST RESULTS WITH THE FONT4 ILC PROTOTYPE INTRA-TRAIN BEAM FEEDBACK SYSTEM
We present the design and beam test results of a prototype beam-based digital feedback system for the Interaction Point of the International Linear Collider. A custom analogue front-end processor, FPGA-based digital signal processing board, and kicker drive amplifier have been designed, built, and tested on the extraction line of the KEK Accelerator Test Facility (ATF). The system was measured to have a latency of approximately 140 ns
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