197 research outputs found
Baldwinian accounts of language evolution
Since Hinton & Nowlan published their seminal paper (Hinton & Nowlan 1987), the
neglected evolutionary process of the Baldwin effect has been widely acknowledged.
Especially in the field of language evolution, the Baldwin effect (Baldwin 1896d,
Simpson 1953) has been expected to salvage the long-lasting deadlocked situation of
modern linguistics: i.e., it may shed light on the relationship between environment
and innateness in the formation of language.However, as intense research of this evolutionary theory goes on, certain robust
difficulties have become apparent. One example is genotype-phenotype correlation.
By computer simulations, both Yamauchi (1999, 2001) and Mayley (19966) show
that for the Baldwin effect to work legitimately, correlation between genotypes and
phenotypes is the most essential underpinning. This is due to the fact that this type
of the Baldwin effect adopts as its core mechanism Waddington's (1975) "genetic
assimilation". In this mechanism, phenocopies have to be genetically closer to the
innately predisposed genotype. Unfortunately this is an overly naiive assumption
for the theory of language evolution. As a highly complex cognitive ability, the
possibility that this type of genotype-phenotype correlation exists in the domain of
linguistic ability is vanishingly small.In this thesis, we develop a new type of mechanism, called "Baldwinian Niche
Construction (BNC), that has a rich explanatory power and can potentially over¬
come this bewildering problem of the Baldwin effect. BNC is based on the theory
of niche construction that has been developed by Odling-Smee et al. (2003). The
incorporation of the theory into the Baldwin effect was first suggested by Deacon
(1997) and briefly introduced by Godfrey-Smith (2003). However, its formulation
is yet incomplete.In the thesis, first, we review the studies of the Baldwin effect in both biology
and the study of language evolution. Then the theory of BNC is more rigorously
developed. Linguistic communication has an intrinsic property that is fundamentally described in the theory of niche construction. This naturally leads us to the
theoretical necessity of BNC in language evolution. By creating a new linguistic
niche, learning discloses a previously hidden genetic variance on which the Baldwin
'canalizing' effect can take place. It requires no genetic modification in a given
genepool. There is even no need that genes responsible for learning occupy the
same loci as genes for the innate linguistic knowledge. These and other aspects of
BNC are presented with some results from computer simulations
Evaluation of water flushing effect on icebreaking operation of “Shirase” by analysis of Japanese Antarctic Research Expedition voyage data
The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Thu. 5 Dec. / 2F Auditorium , National Institute of Polar Researc
Fgf20b is required for the ectomesenchymal fate establishment of cranial neural crest cells in zebrafish.
In cranial skeletal development, the establishment of the ectomesenchymal lineage within the cranial neural crest is of great significance. Fgfs are polypeptide growth factors with diverse functions in development and metabolism. Fgf20b knockdown zebrafish embryos showed dysplastic neurocranial and pharyngeal cartilages. Ectomesenchymal cells from cranial neural crest cells were significantly decreased in Fgf20b knockdown embryos, but cranial neural crest cells with a non-ectomesnchymal fate were increased. However, the proliferation and apoptosis of cranial neural crest cells were essentially unchanged. Fgfr1 knockdown embryos also showed dysplastic neurocranial and pharyngeal cartilages. The present findings indicate that Fgf20b is required for ectomesenchymal fate establishment via the activation of Fgfr1 in zebrafish
Large-scale Filamentary Structure around the Protocluster at Redshift z=3.1
We report the discovery of a large-scale coherent filamentary structure of
Lyman alpha emitters in a redshift space at z=3.1. We carried out spectroscopic
observations to map the three dimensional structure of the belt-like feature of
the Lyman alpha emitters discovered by our previous narrow-band imaging
observations centered on the protocluster at z=3.1. The feature was found to
consist of at least three physical filaments connecting with each other. The
result is in qualitative agreement with the prediction of the 'biased'
galaxy-formation theories that galaxies preferentially formed in large-scale
filamentary or sheet-like mass overdensities in the early Universe. We also
found that the two known giant Lyman alpha emission-line nebulae showing high
star-formation activities are located near the intersection of these filaments,
which presumably evolves into a massive cluster of galaxies in the local
Universe. This may suggest that massive galaxy formation occurs at the
characteristic place in the surrounding large-scale structure at high redshift.Comment: 11 pages, 3 figures, accepted for publication in ApJ Letter
Magnetostriction studies up to megagauss fields using fiber Bragg grating technique
We here report magnetostriction measurements under pulsed megagauss fields
using a high-speed 100 MHz strain monitoring system devised using fiber Bragg
grating (FBG) technique with optical filter method. The optical filter method
is a detection scheme of the strain of FBG, where the changing Bragg wavelength
of the FBG reflection is converted to the intensity of reflected light to
enable the 100 MHz measurement. In order to show the usefulness and reliability
of the method, we report the measurements for solid oxygen, spin-controlled
crystal, and volborthite, a deformed Kagom\'{e} quantum spin lattice, using
static magnetic fields up to 7 T and non-destructive millisecond pulse magnets
up to 50 T. Then, we show the application of the method for the
magnetostriction measurements of CaVO, a two-dimensional
antiferromagnet with spin-halves, and LaCoO, an anomalous spin-crossover
oxide, in the megagauss fields.Comment: 9pages, 6 figures, Conference proceedings for MegaGauss16 at Kashiwa,
Japan in Sept. 201
Quantitative ultrasound can assess the regeneration process of tissue-engineered cartilage using a complex between adherent bone marrow cells and a three-dimensional scaffold
Articular cartilage (hyaline cartilage) defects resulting from traumatic injury or degenerative joint disease do not repair themselves spontaneously. Therefore, such defects may require novel regenerative strategies to restore biologically and biomechanically functional tissue. Recently, tissue engineering using a complex of cells and scaffold has emerged as a new approach for repairing cartilage defects and restoring cartilage function. With the advent of this new technology, accurate methods for evaluating articular cartilage have become important. In particular, in vivo evaluation is essential for determining the best treatment. However, without a biopsy, which causes damage, articular cartilage cannot be accurately evaluated in a clinical context. We have developed a novel system for evaluating articular cartilage, in which the acoustic properties of the cartilage are measured by introducing an ultrasonic probe during arthroscopy of the knee joint. The purpose of the current study was to determine the efficacy of this ultrasound system for evaluating tissue-engineered cartilage in an experimental model involving implantation of a cell/scaffold complex into rabbit knee joint defects. Ultrasonic echoes from the articular cartilage were converted into a wavelet map by wavelet transformation. On the wavelet map, the percentage maximum magnitude (the maximum magnitude of the measurement area of the operated knee divided by that of the intact cartilage of the opposite, nonoperated knee; %MM) was used as a quantitative index of cartilage regeneration. Using this index, the tissue-engineered cartilage was examined to elucidate the relations between ultrasonic analysis and biochemical and histological analyses. The %MM increased over the time course of the implant and all the hyaline-like cartilage samples from the histological findings had a high %MM. Correlations were observed between the %MM and the semiquantitative histologic grading scale scores from the histological findings. In the biochemical findings, the chondroitin sulfate content increased over the time course of the implant, whereas the hydroxyproline content remained constant. The chondroitin sulfate content showed a similarity to the results of the %MM values. Ultrasonic measurements were found to predict the regeneration process of the tissue-engineered cartilage as a minimally invasive method. Therefore, ultrasonic evaluation using a wavelet map can support the evaluation of tissue-engineered cartilage using cell/scaffold complexes
Supplementation of protein-free diet with whey protein hydrolysates prevents skeletal muscle mass loss in rats
AbstractMuscle mass loss is induced by aging, several catabolic diseases, and malnutrition. It is well known that ingestion of whey protein and its hydrolysates (WPH) is effective in stimulating muscle protein synthesis. However, these studies focused on the acute up-regulation of muscle protein synthesis, and few studies have investigated the effect of whey protein and WPH on muscle mass during chronic malnutrition. The aim of the present study was to investigate the effect of 7 days supplementation of whey protein and WPH on muscle reduction in Wistar rats fed a protein-free (PF) diet. Wistar rats were fed either a standard diet (containing 20% protein) or a PF diet during the experimental period. Those fed a PF diet received a dietary supplement containing an amino acid mixture, whey protein, or WPH for 7 days. The weight of the extensor digitorum longus decreased in rats fed a PF diet supplemented with the amino acid mixture or the whey protein. However, this decrease was partially but significantly suppressed in the group fed the WPH supplement. Additionally, administration of WPH induced a postprandial increase in plasma essential amino acids, branched-chain amino acids, and leucine concentration compared with animals fed the amino acid mixture or the whey protein. These results suggest that 7 days supplementation of the diet with WPH suppressed muscle weight loss in rats fed a PF diet
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