509 research outputs found
Differences between Doppler velocities of ions and neutral atoms in a solar prominence
This is the author accepted manuscript. The final version is available from EDP Sciences via the DOI in this record.Context. In astrophysical systems with partially ionized plasma the motion of ions is governed by the magnetic field while the neutral
particles can only feel the magnetic field’s Lorentz force indirectly through collisions with ions. The drift in the velocity between
ionized and neutral species plays a key role in modifying important physical processes like magnetic reconnection, damping of
magnetohydrodynamic waves, transport of angular momentum in plasma through the magnetic field, and heating.
Aims. This paper investigates the differences between Doppler velocities of calcium ions and neutral hydrogen in a solar prominence
to look for velocity differences between the neutral and ionized species.
Methods. We simultaneously observed spectra of a prominence over an active region in H I 397 nm, H I 434 nm, Ca II 397 nm, and
Ca II 854 nm using a high dispersion spectrograph of the Domeless Solar Telescope at Hida observatory, and compared the Doppler
velocities, derived from the shift of the peak of the spectral lines presumably emitted from optically-thin plasma.
Results. There are instances when the difference in velocities between neutral atoms and ions is significant, e.g. 1433 events (∼ 3 %
of sets of compared profiles) with a difference in velocity between neutral hydrogen atoms and calcium ions greater than 3σ of the
measurement error. However, we also found significant differences between the Doppler velocities of two spectral lines emitted from
the same species, and the probability density functions of velocity difference between the same species is not significantly different
from those between neutral atoms and ions.
Conclusions. We interpreted the difference of Doppler velocities as a result of motions of different components in the prominence
along the line of sight, rather than the decoupling of neutral atoms from plasma.This work was supported by a Grant-in-Aid for Scientific
Research (No. 22244013, P.I. K. Ichimoto; No. 15K17609, P.I. T. Anan; No.
16H01177, P.I. T. Anan) from the Ministry of Education, Culture, Sports, Science
and Technology of Japan. A.H. is supported by his STFC Emest Rutherford
Fellowship grant number ST/L00397X/2
Genetic components affecting the interval between consecutive inseminations
International audienc
Modifikasi Latihan Plyometric Terhadap Lompat Tinggi Gaya Straddle Di Sltp
This research has been conducted in order to see the correlation of modification of plyometric practice with the study results of straddle high jump by the third grade students of junior high school 2 Pontianak.The population of this research are all the third grade students of junior high school 2 Pontianak which are 245 students. The sample that have been used in this research are 35 students with purposive sampling. The method that has been used in this research is pre-experimental design.Data analysis are conducted with computerization system and also with t analysis. The analysis results by mc.exel computerization has gained 20,11 of t test with dB=(N-1) is 35-1=34 and when 5% significance, t table value is 2,034 with the increment of percentage is 39,06%. According to the t test result, it can be concluded that there is a correlation between the modification of plyometric practice and the result of straddle high jump
Chromospheric polarimetry through multi-line observations of the 850 nm spectral region
Future solar missions and ground-based telescopes aim to understand the
magnetism of the solar chromosphere. We performed a supporting study in
Quintero Noda et al. (2016) focused on the infrared Ca II 8542 A line and we
concluded that is one of the best candidates because it is sensitive to a large
range of atmospheric heights, from the photosphere to the middle chromosphere.
However, we believe that it is worth to try improving the results produced by
this line observing additional spectral lines. In that regard, we examined the
neighbour solar spectrum looking for spectral lines that could increase the
sensitivity to the atmospheric parameters. Interestingly, we discovered several
photospheric lines that greatly improve the photospheric sensitivity to the
magnetic field vector. Moreover, they are located close to a second
chromospheric line that also belongs to the Ca II infrared triplet, i.e. the Ca
II 8498 A line, and enhances the sensitivity to the atmospheric parameters at
chromospheric layers. We conclude that the lines in the vicinity of the Ca II
8542 A line not only increase its sensitivity to the atmospheric parameters at
all layers, but also they constitute an excellent spectral window for
chromospheric polarimetry.Comment: 11 pages, 8 figures, 1 tabl
Evaluating Influenza Vaccination Practices among COPD Patients
Chronic Obstructive Pulmonary Disease (COPD) stands as a global health concern linked to considerable morbidity and mortality. In Jordan, the prevalence of COPD is substantial, but research in this area is limited. Exacerbations of COPD can lead to severe outcomes, including hospitalization and increased cardiovascular risk. Influenza is a significant trigger of exacerbations in COPD patients, and vaccination is recommended. However, studies have shown negative attitudes towards the influenza vaccine. This cross-sectional study aimed to investigate the knowledge, attitudes, practices, and intentions of COPD patients in Jordan regarding influenza vaccination. Data were collected through a custom-designed questionnaire from 300 COPD patients. The study revealed low influenza vaccination rates, with forgetfulness and lack of knowledge about vaccine effectiveness being the main barriers. Higher knowledge and positive attitudes were associated with greater intention to vaccinate. To tackle these challenges, it is recommended to implement customized health education campaigns, foster collaborations with healthcare providers, and engage in community-focused initiatives to enhance acceptance of the influenza vaccine among COPD patients in Jordan. These findings underscore the importance of addressing knowledge gaps and negative attitudes to enhance vaccine uptake and improve health outcomes for COPD patients
Solar polarimetry through the K I lines at 770 nm
We characterize the K I D1 & D2 lines in order to determine whether they
could complement the 850 nm window, containing the Ca II infrared triplet lines
and several Zeeman sensitive photospheric lines, that was studied previously.
We investigate the effect of partial redistribution on the intensity profiles,
their sensitivity to changes in different atmospheric parameters, and the
spatial distribution of Zeeman polarization signals employing a realistic
magnetohydrodynamic simulation. The results show that these lines form in the
upper photosphere at around 500 km and that they are sensitive to the line of
sight velocity and magnetic field strength at heights where neither the
photospheric lines nor the Ca II infrared lines are. However, at the same time,
we found that their sensitivity to the temperature essentially comes from the
photosphere. Then, we conclude that the K I lines provide a complement to the
lines in the 850 nm window for the determination of atmospheric parameters in
the upper photosphere, especially for the line of sight velocity and the
magnetic field.Comment: 10 pages, 9 figures, main journal publicatio
Early factors for predicting discontinuation to subcutaneous Apomorphine infusion in Parkinson's disease:A prospective analysis of the Thai Apomorphine Registry
INTRODUCTION: Although continuous subcutaneous apomorphine infusion (CSAI) is an effective therapy for Parkinson's disease (PD) with motor fluctuations, data from Asian cohorts is limited. The therapy is often discontinued due to the complexity of its delivery. METHODS: Fifty-one PD patients undergoing CSAI as an add-on therapy were enrolled in the Thai Apomorphine Registry, an electronic database that recorded clinical characteristics and parameters during the 14-consecutive-day titration and long-term follow-up. Factors at the time of titration were documented in order to identify predictors of long-term discontinuation. RESULTS: Following initiation, PD patients were administered a mean CSAI dose of 5.89 mg/h (SD 1.36) over a mean time of 12.28 h (SD 1.90) each day. The mean follow-up period was 626.2 days (SD 619.17). Significant reductions in UPDRS-I, II, III, and IV scores, total NMSQ score, PDQ-8 score, daily off and dyskinesia hours, Timed Up and Go test, walking step test, levodopa-equivalent daily dose, number of times a day the levodopa was taken versus pre-CSAI values were observed (p < 0.05, each). Thirty-five (68.6%) patients discontinued during the follow-up period. Relative risks of variables recorded at the time of titration that determined discontinuation of CSAI therapy were an absence of full-time caregivers, achieving a daily off hours reduction <3.5 h, and NMSQ scores at the time of CSAI titration ≥9.5 points. CONCLUSION: Identifying factors that predict discontinuation of CSAI at the time of its initiation may help physicians to better understand the patient's drug response and how to manage them long-term
Study of the polarization produced by the Zeeman effect in the solar Mg I b lines
The next generation of solar observatories aim to understand the magnetism of
the solar chromosphere. Therefore, it is crucial to understand the polarimetric
signatures of chromospheric spectral lines. For this purpose, we here examine
the suitability of the three Fraunhofer Mg I b1, b2, and b4 lines at 5183.6,
5172.7, and 5167.3 A, respectively. We start by describing a simplified atomic
model of only 6 levels and 3 line transitions for computing the atomic
populations of the 3p-4s (multiplet number 2) levels involved in the Mg I b
line transitions assuming non-local thermodynamic conditions and considering
only the Zeeman effect using the field-free approximation. We test this
simplified atom against more complex ones finding that, although there are
differences in the computed profiles, they are small compared with the
advantages provided by the simple atom in terms of speed and robustness. After
comparing the three Mg I lines, we conclude that the most capable one is the b2
line as b1 forms at similar heights and always show weaker polarization signals
while b4 is severely blended with photospheric lines. We also compare Mg I b2
with the K I D1 and Ca II 8542 A lines finding that the former is sensitive to
the atmospheric parameters at heights that are in between those covered by the
latter two lines. This makes Mg I b2 an excellent candidate for future
multi-line observations that aim to seamlessly infer the thermal and magnetic
properties of different features in the lower solar atmosphere.Comment: 14 pages, 11 figures, and 5 table
Chromospheric polarimetry through multi-line observations of the 850 nm spectral region II: A magnetic flux tube scenario
In this publication we continue the work started in Quintero Noda et al.
(2017) examining this time a numerical simulation of a magnetic flux tube
concentration. Our goal is to study if the physical phenomena that take place
in it, in particular, the magnetic pumping, leaves a specific imprint on the
examined spectral lines. We find that the profiles from the interior of the
flux tube are periodically dopplershifted following an oscillation pattern that
is also reflected in the amplitude of the circular polarization signals. In
addition, we analyse the properties of the Stokes profiles at the edges of the
flux tube discovering the presence of linear polarization signals for the Ca II
lines, although they are weak with an amplitude around 0.5% of the continuum
intensity. Finally, we compute the response functions to perturbations in the
longitudinal field and we estimate the field strength using the weak field
approximation. Our results indicate that the height of formation of the
spectral lines changes during the magnetic pumping process which makes the
interpretation of the inferred magnetic field strength and its evolution more
difficult. These results complement those from previous works demonstrating the
capabilities and limitations of the 850 nm spectrum for chromospheric Zeeman
polarimetry in a very dynamic and complex atmosphere.Comment: 12 pages, 12 figures, 0 tables, MNRAS main journal publicatio
- …