3,281 research outputs found
Transgenesis and Genome Editing in Poultry
The transgenic approach and precise editing of specific loci in the genome have diverse practical uses in animal biotechnology. Recent advances in genome-editing technology, including clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) have helped to generate highly valuable and quality-improved poultry. The production of transgenic and genome-edited birds mainly depends on primordial germ cells (PGCs), which are the progenitor cells of gametes, due to the unique system that is quite different from the mammalian system. This chapter introduces the basic physiology of avian PGCs and the latest PGC-mediated methodologies in transgenesis and genome editing of birds. Based on these techniques, future applications of precisely genome-modulated poultry are discussed to provide opportunities and benefits for humans
The impact of IT vendor to firm’s IT outsourcing
This study seeks to better understand the impact of IT vendor to firm’s IT outsourcing in Korea. Using the event study methodology, we empirically analyze the impact of IT vendor in Korea. IT vendors’ characteristics (such as services with asset specificity, size, and nationality) that may affect the success of IT outsourcing are considered. We find that IT outsourcing announcements significantly increase firms’ market value in Korea. In terms of IT vendors’ characteristics, our study find that IT outsourcing announcements with large vendors are statistically significant while with small vendors are not. We also find that the market response to Korean IT vendor is significantly greater than to foreign vendor. However, unlike the US, the difference between IT outsourcing for high asset-specific service and for low asset-specific service is not found
Charge density functional plus calculation of lacunar spinel GaMSe (M = Nb, Mo, Ta, and W)
Charge density functional plus calculations are carried out to examine
the validity of molecular =1/2 and 3/2 state in lacunar spinel
GaMX (M = Nb, Mo, Ta, and W). With LDA (spin-unpolarized local density
approximation), which has recently been suggested as the more desirable
choice than LSDA (local spin density approximation), we examine the band
structure in comparison with the previous prediction based on the
spin-polarized version of functional and with the prototypical
=1/2 material SrIrO. It is found that the previously
suggested =1/2 and 3/2 band characters remain valid still in
LDA calculations while the use of charge-only density causes some minor
differences. Our result provides the further support for the novel molecular
state in this series of materials, which can hopefully motivate
the future exploration toward its verification and the further search for new
functionalities
Analysis of Laser ARPES from BiSrCaCuO in superconductive state: angle resolved self-energy and fluctuation spectrum
We analyze the ultra high resolution laser angle resolved photo-emission
spectroscopy (ARPES) intensity from the slightly underdoped
BiSrCaCuO in the superconductive (SC) state. The
momentum distribution curves (MDC) were fitted at each energy \w employing
the SC Green's function along several cuts perpendicular to the Fermi surface
with the tilt angle with respect to the nodal cut. The clear
observation of particle-hole mixing was utilized such that the complex
self-energy as a function of is directly obtained from the fitting.
The obtained angle resolved self-energy is then used to deduce the Eliashberg
function \alpha^2 F^{(+)}(\th,\w) in the diagonal channel by inverting the
d-wave Eliashberg equation using the maximum entropy method. Besides a broad
featureless spectrum up to the cutoff energy , the deduced exhibits two peaks around 0.05 eV and 0.015 eV. The former and the broad
feature are already present in the normal state, while the latter emerges only
below . Both peaks become enhanced as is lowered or the angle
moves away from the nodal direction. The implication of these findings are
discussed.Comment: 7 pages, 5 figures, summited to PR
Energy-absorbing origami structure for crashworthiness design
This paper presents experimental and numerical investigations on the origami-patterned tube which is acknowledged as a
promising energy-absorption device. Its buckling mode leads to high performances in terms of specific energy absorption
(SEA) and crush force efficiency (CFE). The polygonal tube is prefolded by following an origami pattern, which is
designed to act as geometric imperfection and mode inducer. First, a series of quasi-static crushing tests are performed on
origami tubes with different materials and geometrical features. Specimens in SUS316L and AlSi10Mg are produced
through Additive Manufacturing (AM). It allows to conveniently produce few samples with a complex shape. Finite
Element Analysis (FEA) and Direct Image Correlation (DIC) are employed for a better insight into the complex crushing
behaviour. The Aluminum tube shows a brittle behaviour while SUS316L tubes have extremely promising performance
until local crack happens. Limits stemming from the employment of AM are explored and a new geometry is designed to
avoid cracking. Second, a numerical design exploration study is carried out to assess the sensitivity of origami pattern
features over the energy-absorption performance. ANSYS Autodyn is utilized as FE solver and DesignXplorer for
correlation and optimization. The benefits of new patterns are investigated through geometrical optimization, and an
improved geometry is proposed. The pattern stiffness is tuned to account for the external boundary conditions, resulting in
a more uniform crushing behaviour. A similar force trend is maintained with a SEA increment of 51.7% due to a drastic
weight reduction in areas with lower influence on post-buckling stiffnes
Precursor Phenomena of Barium Titanate Single Crystals Grown Using a Solid-State Single Crystal Growth Method Studied with Inelastic Brillouin Light Scattering and Birefringence Measurements
The nature of precursor phenomena in the paraelectric phase of ferroelectrics is one of the
main questions to be resolved from a fundamental point of view. Barium titanate (BaTiO3) is one
of the most representative perovskite-structured ferroelectrics intensively studied until now. The
pretransitional behavior of BaTiO3 single crystal grown using a solid-state crystal growth (SSCG)
method was investigated for the first time and compared to previous results. There is no melting
process in the SSCG method, thus the crystal grown using a SSCG method have inherent higher
levels of impurity and defect concentrations, which is a good candidate for investigating the effect of
crystal quality on the precursor phenomena. The acoustic, dielectric, and piezoelectric properties,
as well as birefringence, of the SSCG-grown BaTiO3 were examined over a wide temperature range.
Especially, the acoustic phonon behavior was investigated in terms of Brillouin spectroscopy, which
is a complementary technique to Raman spectroscopy. The obtained precursor anomalies of the
SSCG-grown BaTiO3 in the cubic phase were similar to those of other single crystals, in particular,
of high-quality single crystal grown by top-seeded solution growth method. These results clearly
indicate that the observed precursor phenomena are common and intrinsic effect irrespective of the
crystal quality
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