49 research outputs found
Kimmerle conjecture for the Held and O'Nan sporadic simple groups
Using the Luthar--Passi method, we investigate the Zassenhaus and
Kimmerle conjectures for normalized unit groups of integral group rings of the
Held and O'Nan sporadic simple groups. We confirm the Kimmerle conjecture for
the Held simple group and also derive for both groups some extra information
relevant to the classical Zassenhaus conjecture
TECHNICAL NOTE ON THE INTRODUCTION OF PARTRIDGE COLOURED HUNGARIAN CHICKEN IN THE MEKONG DELTA OF VIETNAM
The paper aims to provide a brief agricultural profile of Tra Vinh province, informative adaptation results of Partridge coloured Hungarian chicken (PH) in Mekong Delta and describe the procedure to introduce PH into Tra Vinh province. During the introducing process, flexibility, consideration of the local condition (temperature, humidity, daily sunlight…), and availability of local resources such as bamboo blind, rice husk is essential for introducing a new chicken breed into Mekong Delta. For this, practical examples are given in the study. Regarding adaptation results, relatively high survival rate (89.6%) of PH was recorded at the end of 8th week. Although the recorded data of PH in Tra Vinh is limited, their performance is expected to be equally good or even better in comparison with that obtained in the sub-tropical climatic zone (North Vietnam). Further studies of PH adaptability in Mekong Delta for sustainable, traditional production and crossing purposes, as well as the involvement of chicken caravans to free range farming are recommended
The Weakening Outburst of the Young Eruptive Star V582 Aur
V582 Aur is a pre-main sequence FU Orionis type eruptive star, which entered
a brightness minimum in 2016 March due to changes in the line-of-sight
extinction. Here, we present and analyze new optical , , and
band multiepoch observations and new near-infrared , and band
photometric measurements from 2018 January2019 February, as well as publicly
available mid-infrared WISE data. We found that the source shows a significant
opticalnear-infrared variability, and the current brightness minimum has not
completely finished yet. If the present dimming originates from the same
orbiting dust clump that caused a similar brightness variation in 2012, than
our results suggest a viscous spreading of the dust particles along the orbit.
Another scenario is that the current minimum is caused by a dust structure,
that is entering and leaving the inner part of the system. The WISE
measurements could be consistent with this scenario. Our long-term data, as
well as an accretion disk modeling hint at a general fading of V582 Aur,
suggesting that the source will reach the quiescent level in 80 years.Comment: 8 pages, 4 figures, accepted for publication in Ap
Association of FcγRIIa R131H polymorphism with idiopathic pulmonary fibrosis severity and progression
<p>Abstract</p> <p>Background</p> <p>A significant genetic component has been described for idiopathic pulmonary fibrosis (IPF). The R131H (rs1801274) polymorphism of the IgG receptor FcγRIIa determines receptor affinity for IgG subclasses and is associated with several chronic inflammatory diseases. We investigated whether this polymorphism is associated with IPF susceptibility or progression.</p> <p>Methods</p> <p>In a case-control study, we compared the distribution of FcγRIIa R131H genotypes in 142 patients with IPF and in 218 controls using allele-specific PCR amplification.</p> <p>Results</p> <p>No differences in the frequency of FcγRIIa genotypes were evident between IPF patients and control subjects. However, significantly impaired pulmonary function at diagnosis was observed in HH compared to RR homozygotes, with evidence of more severe restriction (reduced forced vital capacity (FVC)) and lower diffusing capacity for carbon monoxide (D<smcaps>L</smcaps><sub>CO</sub>). Similarly, increased frequency of the H131 allele was observed in patients with severe disease (D<smcaps>L</smcaps><sub>CO </sub>< 40% predicted) (0.53 vs. 0.38; p = 0.03). Furthermore, the H131 allele was associated with progressive pulmonary fibrosis as determined by > 10% drop in FVC and/or > 15% fall in D<smcaps>L</smcaps><sub>CO </sub>at 12 months after baseline (0.48 vs. 0.33; p = 0.023).</p> <p>Conclusions</p> <p>These findings support an association between the FcγRIIa R131H polymorphism and IPF severity and progression, supporting the involvement of immunological mechanisms in IPF pathogenesis.</p
The effect of dopamine agonists on adaptive and aberrant salience in Parkinson's disease
Clinical evidence suggests that after initiation of dopaminergic medications some patients with Parkinson's disease (PD) develop psychotic symptoms, such as hallucinations and delusions. Here, we tested the hypothesis that the neurocognitive basis of this phenomenon can be defined as the formation of arbitrary and illusory associations between conditioned stimuli and reward signals, called aberrant salience. Young, never-medicated PD patients and matched controls were assessed on a speeded reaction time task in which the probe stimulus was preceded by conditioned stimuli that could signal monetary reward by color or shape. The patients and controls were re-evaluated after 12 weeks during which the patients received a dopamine agonist (pramipexole or ropinirole). Results indicated that dopamine agonists increased both adaptive and aberrant salience in PD patients, that is, formation of real and illusory associations between conditioned stimuli and reward, respectively. This effect was present when associations were assessed by means of faster responding after conditioned stimuli signaling reward (implicit salience) and overt rating of stimulus-reward links (explicit salience). However, unusual feelings and experiences, which are subclinical manifestations of psychotic-like symptoms, were specifically related to irrelevant and illusory stimulus-reward associations (aberrant salience) in PD patients receiving dopamine agonists. The learning of relevant and real stimulus-reward associations (adaptive salience) was not related to unusual experiences. These results suggest that dopamine agonists may increase psychotic-like experiences in young patients with PD, possibly by facilitating dopaminergic transmission in the ventral striatum, which results in aberrant associations between conditioned stimuli and reward
A novel aspect of the structure of the avian thymic medulla.
We provide evidence for the compartmentalization of the avian thymic medulla and identify the avian thymic dendritic cell. The thymic anlage develops from an epithelial cord of the branchial endoderm. Branches of the cord are separated by primary septae of neural crest origin. The dilation of the primary septae produces the keratin-negative area (KNA) of the thymic medulla and fills the gaps of the keratin-positive network (KPN). Morphometric analysis indicates that the KNA takes up about half of the volume of the thymic medulla, which has reticular connective tissue, like peripheral lymphoid organs. The KNA receives blood vessels and in addition to pericytes, the myoid cells of striated muscle structure occupy this area. The myoid cells are of branchial arch or prechordal plate origin providing indirect evidence for the neural crest origin of the KNA. The marginal epithelial cells of the KPN co-express keratin and vimentin intermediate filaments, which indicate their functional peculiarity. The basal lamina of the primary septum is discontinuous on the surface of the KPN providing histological evidence for the loss of the blood-thymus barrier in the medulla. In the center of the KNA, the dendritic cells lie in close association with blood vessels, whereas the B-cells accumulate along the KPN. The organization of the KPN and KNA increases the "surface" of the so-called cortico-medullary border, thereby contributing to the efficacy of central tolerance
SN2017jgh: a high-cadence complete shock cooling light curve of a SN IIb with the Kepler telescope
SN 2017jgh is a type IIb supernova discovered by Pan-STARRS during the C16/C17 campaigns of the Kepler/K2 mission. Here, we present the Kepler/K2 and ground based observations of SN 2017jgh, which captured the shock cooling of the progenitor shock breakout with an unprecedented cadence. This event presents a unique opportunity to investigate the progenitors of stripped envelope supernovae. By fitting analytical models to the SN 2017jgh light curve, we find that the progenitor of SN 2017jgh was likely a yellow supergiant with an envelope radius of ∼50−290R⊙ , and an envelope mass of ∼0−1.7M⊙ . SN 2017jgh likely had a shock velocity of ∼7500−10 300 km s−1. Additionally, we use the light curve of SN 2017jgh to investigate how early observations of the rise contribute to constraints on progenitor models. Fitting just the ground based observations, we find an envelope radius of ∼50−330R⊙ , an envelope mass of ∼0.3−1.7M⊙ and a shock velocity of ∼9000−15 000 km s−1. Without the rise, the explosion time cannot be well constrained that leads to a systematic offset in the velocity parameter and larger uncertainties in the mass and radius. Therefore, it is likely that progenitor property estimates through these models may have larger systematic uncertainties than previously calculated
Detection and Characterization of Oscillating Red Giants: First Results from the TESS Satellite
Since the onset of the "space revolution" of high-precision high-cadence photometry, asteroseismology has been demonstrated as a powerful tool for informing Galactic archeology investigations. The launch of the NASA Transiting Exoplanet Survey Satellite (TESS) mission has enabled seismic-based inferences to go full sky—providing a clear advantage for large ensemble studies of the different Milky Way components. Here we demonstrate its potential for investigating the Galaxy by carrying out the first asteroseismic ensemble study of red giant stars observed by TESS. We use a sample of 25 stars for which we measure their global asteroseimic observables and estimate their fundamental stellar properties, such as radius, mass, and age. Significant improvements are seen in the uncertainties of our estimates when combining seismic observables from TESS with astrometric measurements from the Gaia mission compared to when the seismology and astrometry are applied separately. Specifically, when combined we show that stellar radii can be determined to a precision of a few percent, masses to 5%-10%, and ages to the 20% level. This is comparable to the precision typically obtained using end-of-mission Kepler data
Photometric and Spectroscopic Properties of Type Ia Supernova 2018oh with Early Excess Emission from the Kepler 2 Observations
Supernova (SN) 2018oh (ASASSN-18bt) is the first spectroscopically confirmed Type Ia supernova (SN Ia) observed in the Kepler field. The Kepler data revealed an excess emission in its early light curve, allowing us to place interesting constraints on its progenitor system. Here we present extensive optical, ultraviolet, and near-infrared photometry, as well as dense sampling of optical spectra, for this object. SN 2018oh is relatively normal in its photometric evolution, with a rise time of 18.3 ± 0.3 days and Δm 15(B) = 0.96 ± 0.03 mag, but it seems to have bluer B − V colors. We construct the "UVOIR" bolometric light curve having a peak luminosity of 1.49 × 1043 erg s−1, from which we derive a nickel mass as 0.55 ± 0.04 M ⊙ by fitting radiation diffusion models powered by centrally located 56Ni. Note that the moment when nickel-powered luminosity starts to emerge is +3.85 days after the first light in the Kepler data, suggesting other origins of the early-time emission, e.g., mixing of 56Ni to outer layers of the ejecta or interaction between the ejecta and nearby circumstellar material or a nondegenerate companion star. The spectral evolution of SN 2018oh is similar to that of a normal SN Ia but is characterized by prominent and persistent carbon absorption features. The C ii features can be detected from the early phases to about 3 weeks after the maximum light, representing the latest detection of carbon ever recorded in an SN Ia. This indicates that a considerable amount of unburned carbon exists in the ejecta of SN 2018oh and may mix into deeper layers