58 research outputs found
Some physical implications of recent solar wind measurements
The physical implications of the existence at about 1 AU of a quiet solar wind particle flux about 90 percent larger than that suggested in the past is investigated within the framework of the two-fluid solar wind model equations. During the spherically symmetric radial expansion of the quiet solar wind, the particle flux is conserved quantity. It is found that a pure collisional two-fluid model provides good particle density and streaming velocity at 1 AU, but predicts too large an electron temperature and too small a proton temperature. When noncollisional contributions to the transport coefficients are incorporated in the model equations, a complete satisfactory agreement with the available observations is obtained. Upper limits to the effective coupling between electrons and protons, as well as to the effective proton thermal conductivity, and both upper and lower limits to the effective electron thermal conductivity in the quiet solar wind, required to provide agreement with observations, are given
Application of a MHD hybrid solar wind model with latitudinal dependences to Ulysses data at minimum
In a previous work, Ulysses data was analyzed to build a complete
axisymmetric MHD solution for the solar wind at minimum including rotation and
the initial flaring of the solar wind in the low corona. This model has some
problems in reproducing the values of magnetic field at 1 AU despite the
correct values of the velocity. Here, we intend to extend the previous analysis
to another type of solutions and to improve our modelling of the wind from the
solar surface to 1 AU. We compare the previous results to those obtained with a
fully helicoidal model and construct a hybrid model combining both previous
solutions, keeping the flexibility of the parent models in the appropriate
domain. From the solar surface to the Alfven, point, a three component solution
for velocity and magnetic field is used, reproducing the complex wind geometry
and the well-known flaring of the field lines observed in coronal holes. From
the Alfven radius to 1 AU and further, the hybrid model keeps the latitudinal
dependences as flexible as possible, in order to deal with the sharp variations
near the equator and we use the helicoidal solution, turning the poloidal
streamlines into radial ones. Despite the absence of the initial flaring, the
helicoidal model and the first hybrid solution suffer from the same low values
of the magnetic field at 1 AU. However, by adjusting the parameters with a
second hybrid solution, we are able to reproduce both the velocity and magnetic
profiles observed by Ulysses and a reasonable description of the low corona,
provided that a certain amount of energy deposit exists along the flow. The
present paper shows that analytical axisymmetric solutions can be constructed
to reproduce the solar structure and dynamics from 1 solar radius up to 1 AU.Comment: 12 pages, 16 figure
Silent polymorphisms in the RYR1 gene do not\ud modify the phenotype of the p.4898 I>T\ud pathogenic mutation in central core disease:\ud a case report
Background: Central core disease is a congenital myopathy, characterized by presence of central core-like areas in\ud
muscle fibers. Patients have mild or moderate weakness, hypotonia and motor developmental delay. The disease is\ud
caused by mutations in the human ryanodine receptor gene (RYR1), which encodes a calcium-release channel.\ud
Since the RYR1 gene is huge, containing 106 exons, mutation screening has been limited to three ‘hot spots’, with\ud
particular attention to the C-terminal region. Recent next- generation sequencing methods are now identifying\ud
multiple numbers of variants in patients, in which interpretation and phenotype prevision is difficult.\ud
Case presentation: In a Brazilian Caucasian family, clinical, histopathological and molecular analysis identified a\ud
new case of central core disease in a 48-year female. Sanger sequencing of the C-terminal region of the RYR1\ud
gene identified two different missense mutations: c.14256 A > C polymorphism in exon 98 and c.14693 T > C in\ud
exon 102, which have already been described as pathogenic. Trans-position of the 2 mutations was confirmed\ud
because patient’s daughter, mother and sister carried only the exon 98’s mutation, a synonymous variant that was\ud
subsequently found in the frequency of 013–0,05 of alleles. Further next generation sequencing study of the whole\ud
RYR1 gene in the patient revealed the presence of additional 5 common silent polymorphisms in homozygosis and\ud
8 polymorphisms in heterozygosis.\ud
Conclusions: Considering that patient’s relatives showed no pathologic phenotype, and the phenotype presented\ud
by the patient is within the range observed in other central core disease patients with the same mutation, it was\ud
concluded that the c.14256 A > C polymorphism alone is not responsible for disease, and the associated additional\ud
silent polymorphisms are not acting as modifiers of the primary pathogenic mutation in the affected patient. The\ud
case described above illustrates the present reality where new methods for wide genome screening are becoming\ud
more accessible and able to identify a great variety of mutations and polymorphisms of unknown function in\ud
patients and their families.Fundação de Amparo a Pesquisa do Estado de São Paulo - Centro de Pesquisa, Inovação e Difusão (FAPESP-CEPID)Conselho Nacional de Desenvolvimento CientÃfico e Tecnológico (CNPq-INCT)Associação Brasileira de Distrofia Muscular (ABDIM)CAPES-COFECU
Magnetic Connectivity between Active Regions 10987, 10988, and 10989 by Means of Nonlinear Force-Free Field Extrapolation
Extrapolation codes for modelling the magnetic field in the corona in
cartesian geometry do not take the curvature of the Sun's surface into account
and can only be applied to relatively small areas, \textit{e.g.}, a single
active region. We apply a method for nonlinear force-free coronal magnetic
field modelling of photospheric vector magnetograms in spherical geometry which
allows us to study the connectivity between multi-active regions. We use vector
magnetograph data from the Synoptic Optical Long-term Investigations of the Sun
survey (SOLIS)/Vector Spectromagnetograph(VSM) to model the coronal magnetic
field, where we study three neighbouring magnetically connected active regions
(ARs: 10987, 10988, 10989) observed on 28, 29, and 30 March 2008, respectively.
We compare the magnetic field topologies and the magnetic energy densities and
study the connectivities between the active regions(ARs). We have studied the
time evolution of magnetic field over the period of three days and found no
major changes in topologies as there was no major eruption event. From this
study we have concluded that active regions are much more connected
magnetically than the electric current.Comment: Solar Physic
Resolving the Azimuthal Ambiguity in Vector Magnetogram Data with the Divergence-Free Condition: Application to Discrete Data
We investigate how the divergence-free property of magnetic fields can be
exploited to resolve the azimuthal ambiguity present in solar vector
magnetogram data, by using line-of-sight and horizontal heliographic derivative
information as approximated from discrete measurements. Using synthetic data we
test several methods that each make different assumptions about how the
divergence-free property can be used to resolve the ambiguity. We find that the
most robust algorithm involves the minimisation of the absolute value of the
divergence summed over the entire field of view. Away from disk centre this
method requires the sign and magnitude of the line-of-sight derivatives of all
three components of the magnetic field vector.Comment: Solar Physics, in press, 20 pages, 11 figure
Decay time of type III solar bursts observed at kilometric wavelengths
Type III bursts were observed between 3.5 MHz and 50 kHz by the University of Michigan radio astronomy experiment aboard the OGO-5 satellite.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43731/1/11207_2004_Article_BF00156186.pd
PROFIL WISATAWAN MUSEUM RADYA PUSTAKA SURAKARTA
Anggit Margaret, C9407031 2011. Profil Wisatawan Museum
Radya Pustaka Surakarta. Program Studi Diploma III Usaha Perjalanan
Wisata Fakultas Sastra Dan Seni Rupa Universitas Sebelas Maret Surakarta.
Penelitian tugas akhir ini mengkaji tentang Profil Wisatawan di
Museum Radya Pustaka Surakarta. Tujuan dari penelitian ini adalah untuk
mengetahui dari daerah mana saja wisatawan yang berkunjung ke Museum
Radya Pustaka, bagaimana ciri-ciri wisatawan yang berkunjung ke Museum
Radya Pustaka serta harapan-harapan yang diinginkan wisatawan terhadap
Museum Radya Pustaka.
Penelitian dilakukan dengan metode kualitatif. Pengumpulan data
dilakukan melalui wawancara dengan narasumber wisatawan yang berkujung
di Museum Radya Pustaka Surakarta tempat penulis melakukan penelitian,
serta studi pustaka dan studi dokumen guna menambah sumber data.
Hasil penelitian menunjukkan bahwa (1) Sebagian besar wisatawan
yang datang berasal dari Semarang sebesar 32%. (2) Mayoritas wisatawan
yang berkunjung ke Museum Radya Pustaka berusia antara 17-25 tahun dan
kebanyakan dari mereka adalah pelajar atau mahasiswa dengan prosentase
52%. (3) Sebagian besar wisatawan yang datang ke Museum Radya Pustaka
adalah bertujuan untuk melakukan penelitian yaitu sebesar 34%. (4) Harapan
wisatawan yang berkunjung terhadap kelangsungan Museum Radya Pustaka
sebagian besar adalah agar ditingkatkan lagi pengelolaan dan keamanan
museum, agar kejadian hilangnya benda-benda koleksi museum tidak terulang
lagi dikemudian hari.
Kesimpulan dari hasil penelitian ini bahwa wisatawan yang berkujung
ke Museum Radya Pustaka Surakarta mayoritas berasal dari Semarang,
mayoritas berusia 17-25 tahun dan kebanyakan dari mereka adalah berprofesi
sebagai pelajar dan mahasiswa. Kebanyakan wisatawan yang datang bertujuan
untuk melakukan penelitian, serta harapan wisatawan terhadap Museum
Radya Pustaka adalah supaya lebih ditingkatkan lagi pengelolaan dan
keamanan museum
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