Human embryonic stem (hES) cells are pluripotent cell lines established from the explanted inner cell mass of human blastocysts. Despite their importance for human embryology and regenerative ...medicine, studies on hES cells, unlike those on mouse ES (mES) cells, have been hampered by difficulties in culture and by scant knowledge concerning the regulatory mechanism. Recent evidence from plants and animals indicates small RNAs of approximately 22 nucleotides (nt), collectively named microRNAs, play important roles in developmental regulation. Here we describe 36 miRNAs (from 32 stem-loops) identified by cDNA cloning in hES cells. Importantly, most of the newly cloned miRNAs are specifically expressed in hES cells and downregulated during development into embryoid bodies (EBs), while miRNAs previously reported from other human cell types are poorly expressed in hES cells. We further show that some of the ES-specific miRNA genes are highly related to each other, organized as clusters, and transcribed as polycistronic primary transcripts. These miRNA gene families have murine homologues that have similar genomic organizations and expression patterns, suggesting that they may operate key regulatory networks conserved in mammalian pluripotent stem cells. The newly identified hES-specific miRNAs may also serve as molecular markers for the early embryonic stage and for undifferentiated hES cells.
Halo coronal mass ejections (CMEs) from the Sun are the subset of CMEs, which are more energetic than the normal CMEs. Only the more energetic CMEs are observable in white-light coronagraphs when ...they are traveling along the line of sight (LOS) and a CME is better observed when it is traveling perpendicularly to the LOS. We investigated the flare associated front side halo CMEs, their active regions (ARs) and flare ribbon properties observed during the period of 2010 – 2016 in Solar Cycle 24. The aim of this study is to investigate the statistical relationship between the kinematic properties of CMEs and their source active region and flare ribbon properties. The properties of the solar source region (sunspot classification according to Hale and McIntosh, sunspot area, and the number of spots) and flare ribbons (total unsigned magnetic flux, total unsigned reconnection flux, active region area, and ribbon area) are obtained for the selected events and analyzed to find the dependence of the halo CME properties (linear speed, kinetic energy, space speed, and mass) on the source region characteristics. From the preliminary analysis, 13% of halo CMEs are found to be associated with X-class flares, 52% with M-class flares, and 35% with C-class flares. It is found that many events (45/60) were produced by
β
γ
δ
and
β
γ
Hale-type sunspot groups and Ekc/Dkc/Fkc McIntosh sunspot classes, which implies a degree of complexity of the involved sunspots. We found moderate correlations between the active region properties and CME properties, but strong correlation between the flare ribbons and CME properties. This result indicates that the kinematics of CMEs are determined by the role of magnetic reconnection and the flux related to it. We estimated the synthetic CME mass (using a synthetic CME generated based on a full ice-cream cone structure proposed recently by Na et al.,
Astrophys. J.
906
, 46,
2021
). It is demonstrated that the estimated mass of halo CMEs is 1.44 times (without occulted area) and 2 times (with occulted area) that of the observed CME mass. Further, the relations between the halo CME synthetic mass with the active region and flare ribbon properties have been obtained.
ABSTRACT A recent study discussed the steady-state model for solar wind electrons during quiet time conditions. The electrons emanating from the Sun are treated in a composite three-population ...model-the low-energy Maxwellian core with an energy range of tens of eV, the intermediate ∼102-103 eV energy-range ("halo") electrons, and the high ∼103-105 eV energy-range ("super-halo") electrons. In the model, the intermediate energy halo electrons are assumed to be in resonance with transverse EM fluctuations in the whistler frequency range (∼102 Hz), while the high-energy super-halo electrons are presumed to be in steady-state wave-particle resonance with higher-frequency electrostatic fluctuations in the Langmuir frequency range (∼105 Hz). A comparison with STEREO and WIND spacecraft data was also made. However, ignoring the influence of Langmuir fluctuations on the halo population turns out to be an unjustifiable assumption. The present paper rectifies the previous approach by including both Langmuir and whistler fluctuations in the construction of the steady-state velocity distribution function for the halo population, and demonstrates that the role of whistler-range fluctuation is minimal unless the fluctuation intensity is arbitrarily raised. This implies that the Langmuir-range fluctuations, known as the quasi thermal noise, are important for both halo and super-halo electron velocity distribution.
To prepare for when only single‐view observations are available, we have made a test whether the 3‐D parameters (radial velocity, angular width, and source location) of halo coronal mass ejections ...(HCMEs) from single‐view observations are consistent with those from multiview observations. For this test, we select 44 HCMEs from December 2010 to June 2011 with the following conditions: partial and full HCMEs by SOHO and limb CMEs by twin STEREO spacecraft when they were approximately in quadrature. In this study, we compare the 3‐D parameters of the HCMEs from three different methods: (1) a geometrical triangulation method, the STEREO CAT tool developed by NASA/CCMC, for multiview observations using STEREO/SECCHI and SOHO/LASCO data, (2) the graduated cylindrical shell (GCS) flux rope model for multiview observations using STEREO/SECCHI data, and (3) an ice cream cone model for single‐view observations using SOHO/LASCO data. We find that the radial velocities and the source locations of the HCMEs from three methods are well consistent with one another with high correlation coefficients (≥0.9). However, the angular widths by the ice cream cone model are noticeably underestimated for broad CMEs larger than 100° and several partial HCMEs. A comparison between the 3‐D CME parameters directly measured from twin STEREO spacecraft and the above 3‐D parameters shows that the parameters from multiview are more consistent with the STEREO measurements than those from single view.
Key Points
It is possible to reasonably estimate the 3‐D parameters of HCME from single‐view observations
The 3‐D parameters from single‐view observations are consistent with those from multiview ones
In terms of space weather application, the geometrical triangulation method is the best
Objective
This study assessed trends in the incidence of and survival rates for oral cavity cancer in the Korean population.
Materials and Methods
Data from the Korea Central Cancer Registry were ...extracted for 10 282 patients diagnosed with oral cavity cancer (C01‐C06) between 1999 and 2010 to evaluate the age‐standardised incidence rate, annual percentage change (APC) and 5‐year relative survival rate (RSR) according to gender and age.
Results
In males, the incidence rate slightly decreased APC of −0.2% (P = 0.6427); in females, the incidence rate increased APC of 3.1% (P < 0.05). In males and females, the incidence of oral tongue cancer (C02) significantly increased APC of 2.2% and 4.1%, respectively (P < 0.05). This increase in oral tongue cancer incidence was most prominent in the younger age group (<40 years, APC = 6.1%, P < 0.05). The incidence of buccal cheek cancer increased only among males APC of 4.8% (P < 0.05). The 5‐year RSR improved from 42.7% (1993–1995) to 59.5% (2006–2010), corresponding to an increase of 16.8% from 1993 to 2010 (P < 0.05).
Conclusion
The incidence of oral cavity cancer in females increased, whereas it stabilised or decreased in males. However, the incidence of oral tongue cancer increased in both males and females, especially in the younger age group.
The coronal mass ejections (CMEs) from the sun consist of the plasma and strong magnetic fields (∼4–5 G at 1.3 R⊙) and generally, the fast CMEs are often associated with energetic particles of energy ...few hundreds of MeV. When the fast CMEs are ejected towards the Earth, they can disrupt the flow of solar wind in the heliosphere and impact the Earth's magnetosphere causing known space weather phenomena such as, geomagnetic storms, auroras, communication blackouts, satellite drag and failures. In this work, we have investigated a set of 60 halo coronal mass ejections (CMEs) associated with X-ray flares (≥C1.0) observed in 49 active regions during the period 2010–2016 in solar cycle 24. The X-ray flares and white light CMEs were observed by Geostationary Operational Environmental Satellite (GOES) and the Large Angle Spectrometric Coronagraph (LASCO) coronagraph on the Solar and Heliospheric Observatory (SOHO) satellite, respectively. The active region magnetic properties are obtained from Space - weather HMI Active Region Patch (SHARP) parameters for this set of events. For each active region (AR), the mean value is calculated from a 1-day time series for each of the 16 photospheric magnetic parameters extracted from the vector magnetogram products at a 12-min cadence. The dependency of flare flux and CME kinematics properties on the active region magnetic properties is further confirmed through correlation studies. As a result, we found a moderate to strong correlation value for flare flux and halo CME kinematic properties (like linear speed, space speed and kinetic energy) among the seven (USFLUX, TOTUSJZ, TOTUSJH, ABSNJZH, SAVNCPP, TOTPOT and MEANJZH) SHARP parameters. Most of the events (≥73%) were produced by βγδ, βγ and βδ Hale - type sunspot groups and Ekc/Dkc/Fkc McIntosh sunspot classes. It reveals that the most complex active regions are feasible sources of strong flare-associated halo CME productivity. The front side halo CME kinematic properties depend more on the vertical current helicity and polarity magnetic parameters than the other magnetic parameters. In addition, the flare intensity and speed of CME, calculated using an empirical model with the active region magnetic parameters, are found nearly equal to the observed values. This result will be useful to identify the important magnetic parameters for modelling the occurrence of flare-associated halo CMEs and to understand the physical relationship between them.
JSNS
2
(J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) is an experiment that searches for sterile neutrinos via the observation of
ν
¯
μ
→
ν
¯
e
appearance oscillations using ...muon decay-at-rest neutrinos. The JSNS
2
experiment performed data taking from 2021. In this manuscript, a study of the accidental background is presented. The rate of the accidental background is (
9.29
±
0.39
)
×
10
-
8
/spill with 0.75 MW beam power and comparable to the expected number of signal events.
In this article we examine the occurrence probability of 104 major (
Ip
, at energies > 10 MeV) solar energetic particle events (SEPs) and their peak intensity dependence on source longitude and on ...the characteristics of solar flares/radio-loud (RL) coronal mass ejections (CMEs) during the period November 1997–December 2014. We classified them into three sets of events based on the source longitude (L) of the associated solar flares:
i
) eastern side events (30°E < L ≤ 90°E),
ii
) disk center (30°E ≤ L ≤ 30°W), and
iii
) western side events (30°W < L ≤ 90°W). On average, the mean rise time and duration of SEPs are significantly larger for eastern side events (2168 min and 4.16 days, respectively) than the disk center (1338 min and 2.65 days, respectively) and western side events (662 min and 2.42 days, respectively). The mean peak intensity of SEPs from the disk center (10
3.56
pfu) is found to be greater than that of SEPs from the western (10
2.88
pfu) and eastern (10
2.53
pfu) sides, respectively. The western side events (54%) have significantly higher occurrence probability than the disk center (34%) and eastern side (12%). While there is no significant difference in most of the properties of solar flares and RL CMEs, the eastern side associated RL CMEs are highly decelerated (−29.37 m s
−2
) than the disk center (−17.44 m s
−2
) and western side (−9.09 m s
−2
) events. The relationship between peak intensity of SEPs and peak flux of solar flares shows that the correlation coefficients (
cc
) decrease from the eastern side to the western side: 0.65 (eastern), 0.51 (disk), and 0.35 (western). Interestingly, we found that there is a good correlation between the peak intensity of major SEPs and the speed of the CMEs (
cc
=
0.75
) for disk center. From this study, we have concluded that gradualness depends on source longitude and increases from western to eastern side. It is also inferred that the relationship of peak intensity of SEP events with solar flare flux/CME speed is strongly dependent on source longitude.
PDF
