133 research outputs found
The Developmental Changes in Cube Copying Abilities of Japanese Children with Typical Development
Purpose: The purpose of this study was to analyze the developmental changes in Necker cube copying and isometric perspective cube copying abilities of Japanese children of typical development.Methods and Results: [Study-1] A total of 40 individuals aged 5-18 years participated in Study-1. The Necker cube copying task was administered, and scores were assigned based on the method developed by Yorimitsu et al. (2013). The results showed that the scores increased significantly for children in the 8-9 years age group (p < 0.01).[Study-2] A total of 32 individuals aged 6-10 years participated in Study-2. The isometric perspective cube copying task was administered, and scores were assigned based on the method developed by Otomo (2009). The results showed that the scores increased significantly for children in the 7-8 years age group (p < 0.05).Conclusions: Japanese children of typical development were able to perform the Necker cube copying task from approximately nine years of age. The same participants were able to perform the isometric perspective cube copying task from approximately eight years of age
Spearmint Extract Containing Rosmarinic Acid Suppresses Amyloid Fibril Formation of Proteins Associated with Dementia
Neurological dementias such as Alzheimer’s disease and Lewy body dementia are thought to be caused in part by the formation and deposition of characteristic insoluble fibrils of polypeptides such as amyloid beta (Aβ), Tau, and/or α-synuclein (αSyn). In this context, it is critical to suppress and remove such aggregates in order to prevent and/or delay the progression of dementia in these ailments. In this report, we investigated the effects of spearmint extract (SME) and rosmarinic acid (RA; the major component of SME) on the amyloid fibril formation reactions of αSyn, Aβ, and Tau proteins in vitro. SME or RA was added to soluble samples of each protein and the formation of fibrils was monitored by thioflavin T (ThioT) binding assays and transmission electron microscopy (TEM). We also evaluated whether preformed amyloid fibrils could be dissolved by the addition of RA. Our results reveal for the first time that SME and RA both suppress amyloid fibril formation, and that RA could disassemble preformed fibrils of αSyn, Aβ, and Tau into non-toxic species. Our results suggest that SME and RA may potentially suppress amyloid fibrils implicated in the progression of Alzheimer’s disease and Lewy body dementia in vivo, as well
Thermodynamic properties of small flares in the quiet Sun observed by H and EUV: plasma motion of the chromosphere and time evolution of temperature/emission measure
Small flares frequently occur in the quiet Sun. Previous studies have noted
that they share many common characteristics with typical solar flares in active
regions. However, their similarities and differences are not fully understood,
especially their thermal properties. In this study, we performed imaging
spectroscopic observations in the H line taken with the Solar Dynamics
Doppler Imager on the Solar Magnetic Activity Research Telescope (SMART/SDDI)
at the Hida Observatory and imaging observations with the Atmospheric Imaging
Assembly onboard Solar Dynamics Observatory (SDO/AIA). We analysed 25 cases of
small flares in the quiet Sun over the thermal energy range of
, paying particular attention to their thermal
properties. Our main results are as follows: (1) We observe a redshift together
with line centre brightening in the H line associated with more than
half of the small flares. (2) We employ differential emission measure analysis
using AIA multi-temperature (channel) observations to obtain the emission
measure and temperature of the small flares. The results are consistent with
the Shibata & Yokoyama (1999, 2002) scaling law. From the scaling law, we
estimated the coronal magnetic field strength of small flares to be 5 --15 G.
(3) The temporal evolution of the temperature and the density shows that the
temperature peaks precede the density peaks in more than half of the events.
These results suggest that chromospheric evaporations/condensations play an
essential role in the thermal properties of some of the small flares in the
quiet Sun, as does for large flares.Comment: 14 pages, 12 figures, accepted for publication in MNRA
Unified Relationship between Cold Plasma Ejections and Flare Energies Ranging from Solar Microflares to Giant Stellar Flares
We often find spectral signatures of chromospheric cold plasma ejections
accompanied by flares in a wide range of spatial scales in the solar and
stellar atmospheres. However, the relationship between physical quantities
(such as mass, kinetic energy, and velocity) of cold ejecta and flare energy
has not been investigated in a unified manner for the entire range of flare
energies to date. This study analyzed the spectra of cold plasma ejections
associated with small-scale flares and solar flares (energy
) to supply smaller energy samples. We performed
H imaging spectroscopy observation by the Solar Dynamics Doppler Imager
on the Solar Magnetic Activity Research Telescope (SMART/SDDI). We determined
the physical quantities of the ejecta by cloud model fitting to the H
spectrum. We determined flare energy by differential emission measure analysis
using Atmospheric Imaging Assembly onboard Solar Dynamics Observatory (SDO/AIA)
for small-scale flares and by estimating the bolometric energy for large-scale
flares. As a result, we found that the ejection mass and the total flare
energy follow a relation of . We show that the scaling law derived from a simple
physical model explains the solar and stellar observations with a coronal
magnetic field strength as a free parameter. We also found that the kinetic
energy and velocity of the ejecta correlate with the flare energy. These
results suggest a common mechanism driven by magnetic fields to cause cold
plasma ejections with flares on the Sun and stars.Comment: 23 pages, 10 figures; accepted for publication in Ap
Relationship between three-dimensional velocity of filament eruptions and CME association
AbstractIt is widely recognised that filament disappearances or eruptions are frequently associated with Coronal Mass Ejections (CMEs). Since CMEs are a major source of disturbances of the space environment surrounding the Earth, it is important to investigate these associations in detail for the better prediction of CME occurrence. However, the proportion of filament disappearances associated with CMEs is under debate. The estimates range from
∼
10 to
∼
90% and could be affected by the manners to select the events. In this study, we aim to reveal what parameters control the association between filament eruptions and CMEs. We analysed the relationships between CME associations and the physical parameters of filaments including their length, maximum ascending velocity, and direction of eruptions using 28 events of filament eruptions observed in H
α
. We found that the product of the maximum radial velocity and the filament length is well correlated with the CME occurrence. If the product is larger than
8.0
×
10
6
km
2
s
-
1
, the filament will become a CME with a probability of 93%, and if the product is smaller than this value, it will not become a CME with a probability of 100%. We suggest a kinetic-energy threshold above which filament eruptions are associated with CMEs. Our findings also suggest the importance of measuring the velocity vector of filament eruption in three-dimensional space for the better prediction of CME occurrence.</jats:p
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