684 research outputs found
Reproductive Biology and Adaptability of the Invasive Alien Freshwater Amphipod Crangonyx floridanus (Crustacea: Amphipoda, Crangonyctidae)
We studied the reproductive biology and adaptability of the alien freshwater crangonyctid amphipod Crangonyx floridanus, currently inhabiting a large portion of Japan, both in the field and under controlled laboratory conditions. In the Chikuma River population of this alien amphipod, egg-bearing individuals were found throughout the year. In terms of egg maturation cycle, egg development (during embryogenesis), and egg count per ovipositional cycle, these amphipods display a very efficient reproductive system. This study also established their adaptability to a wide range of water temperatures (primarily 4-20 degrees C, however in some cases, these individuals are able to survive at up to 30 degrees C). C. floridanus's strong capacity to adapt to broad and variable environmental conditions is certainly contributing to its high rate of population increase, and rapid dispersion throughout Japan.ArticleZOOLOGICAL SCIENCE. 27(6):522-527 (2010)journal articl
Dental Implant Systems
Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with vital hard/soft tissue and is subjected to chemical as well as mechanical bio-environments. Such requirements should, at least, include biological compatibility, mechanical compatibility, and morphological compatibility to surrounding vital tissues. In this review, based on carefully selected about 500 published articles, these requirements plus MRI compatibility are firstly reviewed, followed by surface texturing methods in details. Normally dental implants are placed to lost tooth/teeth location(s) in adult patients whose skeleton and bony growth have already completed. However, there are some controversial issues for placing dental implants in growing patients. This point has been, in most of dental articles, overlooked. This review, therefore, throws a deliberate sight on this point. Concluding this review, we are proposing a novel implant system that integrates materials science and up-dated surface technology to improve dental implant systems exhibiting bio- and mechano-functionalities
Effective long-time phase dynamics of limit-cycle oscillators driven by weak colored noise
An effective white-noise Langevin equation is derived that describes
long-time phase dynamics of a limit-cycle oscillator subjected to weak
stationary colored noise. Effective drift and diffusion coefficients are given
in terms of the phase sensitivity of the oscillator and the correlation
function of the noise, and are explicitly calculated for oscillators with
sinusoidal phase sensitivity functions driven by two typical colored Gaussian
processes. The results are verified by numerical simulations using several
types of stochastic or chaotic noise. The drift and diffusion coefficients of
oscillators driven by chaotic noise exhibit anomalous dependence on the
oscillator frequency, reflecting the peculiar power spectrum of the chaotic
noise.Comment: 16 pages, 6 figure
Rapid expansion of the distributional range and the population genetic structure of the freshwater amphipod Crangonyx floridanus in Japan
The freshwater amphipod Crangonyx floridanus (Amphipoda: Crangonyctidae) is considered to have been recently introduced from North America to Japan, and the recorded sites at which it has been collected now cover nearly all of Japan except for the northern part. In this study, we surveyed further areas outside of its known distribution range, and examined the population genetic structure and the phylogenetic relationships between Japanese and North American populations of this species based on nuclear (18S rRNA) and mitochondrial (COI) DNA sequences. We found that this amphipod has already reached Hokkaido, northernmost Japan, which suggests that it has undergone rapid expansion in a pattern of concentric circles from the central part of Japan. Genetic analysis showed that the Japanese population is genetically homogeneous, in contrast to the genetic diversification of this species seen in North American Crangonyx populations. The process of introducing, establishing, and expanding this amphipod in Japan may be explained as follows. A limited number of individuals from a North American native population were probably inadvertently introduced and established somewhere within the Kanto region. The local population size then increased and its distribution range expanded rapidly across Japan.ArticleLIMNOLOGY. 12(1):75-82 (2011)journal articl
Elastic properties of the Non-Fermi liquid metal and the Dense Kondo semiconductor
We have investigated the elastic properties of the Ce-based filled
skutterudite antimonides CeRuSb and CeOsSb by means
of ultrasonic measurements. CeRuSb shows a slight increase around
130 K in the temperature dependence of the elastic constants ,
(-)/2 and . No apparent softening toward low
temperature due to a quadrupolar response of the 4-electronic ground state
of the Ce ion was observed at low temperatures. In contrast CeOsSb
shows a pronounced elastic softening toward low temperature in the longitudinal
as a function of temperature () below about 15 K, while a slight
elastic softening was observed in the transverse below about 1.5 K.
Furthermore, CeOsSb shows a steep decrease around a phase
transition temperature of 0.9 K in both and. The elastic
softening observed in below about 15 K cannot be explained
reasonably only by the crystalline electric field effect. It is most likely to
be responsible for the coupling between the elastic strain and the
quasiparticle band with a small energy gap in the vicinity of Fermi level. The
elastic properties and the 4 ground state of Ce ions in CeRuSb
and CeOsSb are discussed from the viewpoint of the crystalline
electric field effect and the band structure in the vicinity of Fermi level.Comment: 9 pages, 11 figures, regular pape
Geometric Features Informed Multi-person Human-object Interaction Recognition in Videos
Human-Object Interaction (HOI) recognition in videos is important for
analyzing human activity. Most existing work focusing on visual features
usually suffer from occlusion in the real-world scenarios. Such a problem will
be further complicated when multiple people and objects are involved in HOIs.
Consider that geometric features such as human pose and object position provide
meaningful information to understand HOIs, we argue to combine the benefits of
both visual and geometric features in HOI recognition, and propose a novel
Two-level Geometric feature-informed Graph Convolutional Network (2G-GCN). The
geometric-level graph models the interdependency between geometric features of
humans and objects, while the fusion-level graph further fuses them with visual
features of humans and objects. To demonstrate the novelty and effectiveness of
our method in challenging scenarios, we propose a new multi-person HOI dataset
(MPHOI-72). Extensive experiments on MPHOI-72 (multi-person HOI), CAD-120
(single-human HOI) and Bimanual Actions (two-hand HOI) datasets demonstrate our
superior performance compared to state-of-the-arts.Comment: Accepted by ECCV 202
Phenomenology of the chiral -wave state in the hexagonal pnictide superconductor SrPtAs
The pairing symmetry of the hexagonal pnictide superconductor SrPtAs is
discussed with taking into account its multiband structure. The topological
chiral -wave state with time-reversal-symmetry breaking has been anticipated
from the spontaneous magnetization observed by the muon-spin-relaxation
experiment. We point out in this paper that the recent experimental reports on
the nuclear-spin-lattice relaxation rate and superfluid density
, which seemingly support the conventional -wave pairing, are also
consistent with the chiral -wave state. The compatibility of the gap and
multiband structures is crucial in this argument. We propose that the
measurement of the bulk quasiparticle density of states would be useful for the
distinction between two pairing states.Comment: 6 pages, 6 figures. arXiv admin note: substantial text overlap with
arXiv:1902.1051
Anomalous elastic softening of SmRu_{4}P_{12} under high pressure
The filled skutterudite compound SmRu_4P_{12} undergoes a complex evolution
from a paramagnetic metal (phase I) to a probable multipolar ordering insulator
(phase II) at T_{MI} = 16.5 K, then to a magnetically ordered phase (phase III)
at T_{N} = 14 K. Elastic properties under hydrostatic pressures were
investigated to study the nature of the ordering phases. We found that distinct
elastic softening above T_{MI} is induced by pressure, giving evidence of
quadrupole degeneracy of the ground state in the crystalline electric field. It
also suggests that quadrupole moment may be one of the order parameters below
T_{MI} under pressure. Strangely, the largest degree of softening is found in
the transverse elastic constant C_{T} at around 0.5-0.6 GPa, presumably having
relevancy to the competing and very different Gruneisen parameters \Omega of
T_{MI} and T_{N}. Interplay between the two phase transitions is also verified
by the rapid increase of T_{MI} under pressure with a considerably large \Omega
of 9. Our results can be understood on the basis of the proposed octupole
scenario for SmRu_4P_{12}.Comment: 7 pages, 7 figure
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