404 research outputs found
Temperature-dependent evolutions of excitonic superfluid plasma frequency in a srong excitonic insulator candidate, TaNiSe
We investigate an interesting anisotropic van der Waals material,
TaNiSe, using optical spectroscopy. TaNiSe has been
known as one of the few excitonic insulators proposed over 50 years ago.
TaNiSe has quasi-one dimensional chains along the -axis. We have
obtained anisotropic optical properties of a single crystal TaNiSe
along the - and -axes. The measured - and -axis optical
conductivities exhibit large anisotropic electronic and phononic properties.
With regard to the -axis optical conductivity, a sharp peak near 3050
cm at 9 K, with a well-defined optical gap ( 1800
cm) and a strong temperature-dependence, is observed. With an increase
in temperature, this peak broadens and the optical energy gap closes around
325 K(). The spectral weight redistribution with respect to the
frequency and temperature indicates that the normalized optical energy gap
() is . The
temperature-dependent superfluid plasma frequency of the excitonic condensation
in TaNiSe has been determined from measured optical data. Our
findings may be useful for future research on excitonic insulators.Comment: 17 pages, 5 figure
Forage Rye Cultivars for Animal Feed in Korea
Rye (Secale cereal L.) is well known for its overwintering ability and has the highest tolerance to cold temperature of the small grain cereals such as wheat, barley, and oat. Rye is used as livestock pasture and as green manure in Korea, and its cultivation area for fodder is about 50,000 ha in 2014. Most rye is grown as a fall-sown annual crop, generally called “winter rye”. In Korea, rye cultivation for whole crop silage (WCS) in the winter-season rice field can be considered as a promising way to enhance feed supply. The WCS production can be an efficient way to use farm products as livestock feed, and it can also contribute to increasing farm income. Although rye is inferior in several ways to the predominant cereal crops (wheat, rice, and maize), it will continue to be an important crop for farmers in Korea because of its winter hardiness and early harvesting by rapid growing ability
The Globular Cluster System of M60 (NGC 4649). I. CFHT MOS Spectroscopy and Database
We present the measurement of radial velocities for globular clusters in M60,
giant elliptical galaxy in the Virgo cluster. Target globular cluster
candidates were selected using the Washington photometry based on the deep
16\arcmin \times 16\arcmin images taken at the KPNO 4m and using the
photometry derived from the HST/WFPC2 archive images. The spectra of the target
objects were obtained using the Multi-Object Spectrograph (MOS) at the
Canada-France-Hawaii Telescope (CFHT). We have measured the radial velocity for
111 objects in the field of M60: 93 globular clusters (72 blue globular
clusters with and 21 red globular clusters with
), 11 foreground stars, 6 small galaxies, and the nucleus of
M60. The measured velocities of the 93 globular clusters range from
km s to km s, with a mean value of
km s, which is in good agreement with the velocity of the nucleus of M60
( km s). Combining our results with data in the
literature, we present a master catalog of radial velocities for 121 globular
clusters in M60. The velocity dispersion of the globular clusters in the master
catalog is found to be km s for the entire sample,
km s for 83 blue globular clusters, and
km s for 38 red globular clusters.Comment: 29 pages, 8 figures. To appear in Ap
Soft X-ray Absorption and Photoemission Studies of Ferromagnetic Mn-Implanted 3-SiC
We have performed x-ray photoemission spectroscopy (XPS), x-ray absorption
spectroscopy (XAS), and resonant photoemission spectroscopy (RPES) measurements
of Mn-implanted 3-SiC (3-SiC:Mn) and carbon-incorporated MnSi
(MnSi:C). The Mn 2 core-level XPS and XAS spectra of 3-SiC:Mn
and MnSi:C were similar to each other and showed "intermediate"
behaviors between the localized and itinerant Mn 3 states.
The intensity at the Fermi level was found to be suppressed in 3-SiC:Mn
compared with MnSi:C. These observations are consistent with the
formation of MnSi:C clusters in the 3-SiC host, as observed in a
recent transmission electron microscopy study.Comment: 4 pages, 3 figure
Calpain-mediated proteolysis of polycystin-1 C-terminus induces JAK2 and ERK signal alterations
AbstractAutosomal dominant polycystic kidney disease (ADPKD), a hereditary renal disease caused by mutations in PKD1 (85%) or PKD2 (15%), is characterized by the development of gradually enlarging multiple renal cysts and progressive renal failure. Polycystin-1 (PC1), PKD1 gene product, is an integral membrane glycoprotein which regulates a number of different biological processes including cell proliferation, apoptosis, cell polarity, and tubulogenesis. PC1 is a target of various proteolytic cleavages and proteosomal degradations, but its role in intracellular signaling pathways remains poorly understood. Herein, we demonstrated that PC1 is a novel substrate for μ- and m-calpains, which are calcium-dependent cysteine proteases. Overexpression of PC1 altered both Janus-activated kinase 2 (JAK2) and extracellular signal-regulated kinase (ERK) signals, which were independently regulated by calpain-mediated PC1 degradation. They suggest that the PC1 function on JAK2 and ERK signaling pathways might be regulated by calpains in response to the changes in intracellular calcium concentration
The Globular Cluster System of M60 (NGC 4649). II. Kinematics of the Globular Cluster System
We present a kinematic analysis of the globular cluster (GC) system in the
giant elliptical galaxy (gE) M60 in the Virgo cluster. Using the photometric
and spectroscopic database of 121 GCs (83 blue GCs and 38 red GCs), we have
investigated the kinematics of the GC system. We have found that the M60 GC
system shows a significant overall rotation. The rotation amplitude of the blue
GCs is slightly smaller than or similar to that of the red GCs, and their
angles of rotation axes are similar. The velocity dispersions about the mean
velocity and about the best fit rotation curve for the red GCs are marginally
larger than those for the blue GCs. Comparison of observed stellar and GC
velocity dispersion profiles with those calculated from the stellar mass
profile shows that the mass-to-light ratio should be increased as the
galactocentric distance increases, indicating the existence of an extended dark
matter halo. The entire sample of GCs in M60 is found to have a tangentially
biased velocity ellipsoid unlike the GC systems in other gEs. Two subsamples
appear to have different velocity ellipsoids. The blue GC system has a modest
tangentially biased velocity ellipsoid, while the red GC system has a modest
radially biased or an isotropic velocity ellipsoid. From the comparison of the
kinematic properties of the M60 GC system to those of other gEs (M87, M49, NGC
1399, NGC 5128, and NGC 4636), it is found that the velocity dispersion of the
blue GC system is similar to or larger than that of the red GC system except
for M60, and the rotation of the GC system is not negligible. The entire sample
of each GC system shows an isotropic velocity ellipsoid except for M60, while
the subsamples show diverse velocity ellipsoids. We discuss the implication of
these results for the formation models of the GC system in gEs.Comment: 48 pages, 16 figures. To appear in Ap
Development of Barley Cultivars for Animal Forage in Korea
In Korea, the domestic consumption of barley as a cereal crop has been decreasing since the 1980s. It has been considered that crop production in the winter-season rice fields could enhance the global competitiveness of domestic livestock industry by providing better quality fodder to livestock and enhancing field use rate. Therefore, the purpose of barley cultivation for cereal food production has been recently replaced by the production of the barley for forage use. Consequently, the area of barley cultivation for forage is markedly increasing in Korea. While any type of barley can be used as forage for feeding cattle, whole crop barley delivers a higher dry matter yield than conventional feed barley. This paper described the present state of forage barley cultivars developed in Korea
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