Resonant interaction of Rossby waves in two-dimensional flow on a β plane

An incompressible two-dimensional flow on a β plane is considered. The β plane is a tangent plane of a sphere to approximately describe fluid motion on a rotating sphere assuming that the Coriolis parameter is a linear function of the latitude. Rossby waves are expected to dominate the β plane dynamics, and here in this paper, a mathematical support for the crucial role of the resonant pairs of the Rossby waves is given

東シナ海・黄海産アンコウとキアンコウの年齢,成長および生殖に関する研究

CHAPTER I AGE AND GROWTH OF LOPHIOMUS SETIGERUS CHAPTER II REPRODUCTION OF LOPHIOMUS SETIGERUS CHAPTER III AGE AND GROWTH OF LOPHIUS LITULON CHAPTER IV REPRODUCTION OF LOPHIUS LITULONMade available in DSpace on 2012-09-06T05:02:27Z (GMT). No. of bitstreams: 2 yoneda1.pdf: 11972837 bytes, checksum: 6abc7528c1c3bbd9901f3d9d6f7f9777 (MD5) yoneda2.pdf: 7713519 bytes, checksum: 4d9736be2bcc85fa76fdecee1f89b0f4 (MD5) Previous issue date: 1998-03-27主1-参

Increased expression of kisspeptin and GnRH forms in the brain of scombroid fish during final ovarian maturation and ovulation

BACKGROUND: Kisspeptins (Kiss) are prime players in the control of reproductive function through their regulation of gonadotropin-releasing hormone (GnRH) expression in the brain. The experimental scombroid fish, chub mackerel (Scomber japonicus) expresses two kiss (kiss1 and kiss2) and three gnrh (gnrh1, gnrh2, and gnrh3) forms in the brain. In the present study, we analyzed expression changes of kiss and gnrh mRNAs in the brain and corresponding GnRH peptides in the brain and pituitary during final ovarian maturation (FOM) and ovulation. METHODS: Female fish possessing late vitellogenic oocytes were injected with GnRH analogue to induce FOM and ovulation. Fish were observed for daily spawning activities and sampled one week post-injection at germinal vesicle migration (GVM), oocyte hydration, ovulation, and post-ovulatory time periods. Changes in relative mRNA levels of kiss and gnrh forms in the brain were determined using quantitative real-time PCR. Changes in GnRH peptides in the brain and pituitary were analyzed using time-resolved fluoroimmunoassay. RESULTS: Both kiss1 and kiss2 mRNA levels in the brain were low at late vitellogenic stage and increased significantly during the GVM period. However, kiss1 mRNA levels decreased during oocyte hydration before increasing again at ovulatory and post-ovulatory periods. In contrast, kiss2 mRNA levels decreased at ovulatory and post-ovulatory periods. Levels of gnrh1 mRNA in the brain increased only during post-ovulatory period. However, levels of gnrh2 and gnrh3 mRNAs were elevated during GVM and then, decreased during oocyte hydration before increasing again at ovulatory period. During post-ovulatory period, both gnrh2 and gnrh3 mRNA levels declined. Peptide levels of all three GnRH forms in the brain were elevated during GVM and oocyte hydration; their levels were significantly lower during late vitellogenic, ovulatory, and post-ovulatory periods. In contrast, pituitary GnRH peptide levels did not show any significant fluctuations, with the GnRH1 peptide levels being many-fold higher than the GnRH2 and GnRH3 forms. CONCLUSION: The results indicate increased expression of multiple Kiss and GnRH forms in the brain and suggest their possible involvement in the regulation of FOM and ovulation in captive female chub mackerel

チタン鋳造における鋳型温度の影響

The purpose of this study was to evaluate the titanium castability with a vacuum pressured type casting machine. We tested ethyl-silicate bonded investment "TITAVESTPS" of metal frame work. Four different mold temperatures (room temperature, 300℃, 600℃, and 900℃) were prepared for the present study, and casting was done in five times in each condition. When the mold temperature increased, high percentage of castability was gained. Mold temperature showed a highly significant (p<0.001) correlation on the castability. These results indicate that high performance of castability on the titanium was achieved when the mold temperature increased by using vacuum pressured type casting machine

Resonant interaction of Rossby waves in two-dimensional flow on a plane

An incompressible two-dimensional flow on a β plane is considered. Rossby waves are generally expected to dominate the β plane dynamics, and here in this paper we prove a mathematically rigorous theorem: that at a high β, the flow dynamics is governed exclusively by the resonant interactions of Rossby waves

Do early growth dynamics explain recruitment success in Japanese flounder Paralichthys olivaceus off the Pacific coast of northern Japan?

We examined the relative importance of growth-related processes operating during the larval and early juvenile stage in explaining variability in year class success of Japanese flounder off the Pacific coast of northern Japan. Early growth trajectory of larvae and juveniles sampled in 2005 (strong year class) and in 2006 (weak year class) was estimated from the analysis of the lapillar otolith. The larval pelagic stage was characterized by lower growth and developmental rates, as well as high selection for fast growth in the metamorphosis/settlement period, during the strong recruitment event of 2005 relative to 2006. Growth appeared higher in 2005 only after settlement despite high density in the nursery, which likely reflected superior productivity during that year combined with an increased probability of cannibalism from early settlers on late settlers. This implies that larval growth dynamics did not play an important role in determining recruitment strength in the two years considered. The decreasing distance from the nursery areas of pelagic larvae through ontogeny in 2005, combined with low age at settlement, suggest that larvae benefited from positive transport conditions during the dominant year class. To the contrary, unfavorable hydrographic conditions likely prevailed in 2006 as distance from the nurseries increased with ontogeny and settlement occurred later than in 2005 despite faster growth potential and developmental rate. We conclude that transport conditions to the nursery grounds, rather than larval growth potential, represented the most important determinant of year class success in the two years considered

Population Subdivision of Japanese Flounder Paralichthys olivaceus in the Pacific Coast of Tohoku Japan Detected by Means of Mitochondrial Phylogenetic Information

This study deals with mitochondrial phylogenetic information of Japanese flounder in the Pacific coast of Tohoku Japan to estimate the genetic population subdivision that was undetectable by conventional population statistics. We determined complete sequences of mitochondrial NADH dehydrogenase subunit-2 (ND2) and subunit-5 (ND5) genes for 151 individuals from northern (Aomori and Iwate prefectures, 40–41°N) and southern (Miyagi and Fukushima prefectures, 37–38°N) waters. Samples from both waters showed high genetic diversity, including 126 haplotypes. These haplotypes were located at mixed and nested positions on an inferred phylogenetic tree, and traditional F-statistics indicated no significant population divergence (φST = −0.00335, p &gt; 0.05), corroborating our previous study. Three variable sites, however, showed significant base composition heterogeneity between samples from the northern and southern waters (Fisher’s exact-test, p &lt; 0.01). Nucleotide substitutions at the three sites converged on an apical clade, which consisted of the five southern individuals, whereas its sister clade consisted only of the three northern individuals. This phylogenetic information corroborates previous ecological studies indicating the presence of separate stocks in the northern and southern waters