Parentage determination of black sea bream(Acanthopagrus schlegelii)for stock enhancement:effectiveness and loss of genetic variation

The stock enhancement programs for black sea bream Acanthopagrus schlegelii have been conducted in China for a fewyears.However,little information has been reported concerning the effectiveness and genetic effect of black sea bream stock enhancement.In order to detect the contribution of released individuals in Zhujiang River Estuary(ZRE)and Daya Bay(DB),six microsatellite markers were used to identify the hatchery-released individuals.In addition,this pedigree of hatchery populations(broodfish and hatchery-released offspring)was traced to detect the number of effective parents(N_(e)),the inbreeding coefficient and the decrease of genetic variability in the reproduction.The pedigree reconstruction showed that at least 69(out of 93)broodfish had offspring.The estimated N_(e) was 54.8,consequently the inbreeding coefficient was 0.91%.The genetic diversity of hatchery-released offspring was lower than that in that of broodfish(heterozygosity alleles,0.727-0.774),some alleles(number of alleles,61-69)and genetic variance were lost during reproduction.It was observed that wild samples had higher levels of genetic diversity compared with hatchery populations as well as recaptured samples in releasing area.A total of 128 hatchery-released black sea bream were identified among 487 recaptured samples in ZRE,while a total of 15 samples were identified among 96 samples in DB.In summary,there was a high survival of released fish.N_(e)vertheless,the results provided evidence to consider a loss of genetic variation in hatcheryreleased stock and a negative genetic effect of the stock enhancement.

Was there a Portfolio Effect of the Micro-economic Leverage ？ Some Empirical Evidence from the Chinese Stock Market

The study is on a linear model of the relationship between the systematic risk and the micro-economic leverage and analyzed the data from the steel, energy source and chemical fibre industry listed companies in the Chinese stock market in 2002 and 2001. Using the linear regression method, empirical equations were found. The portfolio effect was shown so that some empirical evidence had been found to support the micro-economic leverage portfolio effect theory, which was that the listed companies balanced the operating and financial leverage to minimize the systematic risk.

N,N'-bis(3-Chlorophenyl)urea

The title compound (C 13 H 10 N 2OCl 2, M r = 281.13) was synthesized and its crystal structure was determined by X ray analysis. The crystal belongs to orthorhombic system, space group P22 12 1 with a = 4.589(1), b = 9.725(1), c = 14.385(1), V = 642.0(7) 3, Z =2, D c =1.454Mg·m -3 , F(000) = 288, μ (Mo Kα ) = 0.493mm -1 , final R=0\^0466, wR= 0.1216 for 662 observable reflections with I>2σ(I ). In the crystal of the title compound, the molecule has a crystallographic two fold axis through C(1)-O(1) bond of the carbonyl group. The molecules in the crystal are linked together by a bifurcated N-H…O intermolecular hydrogen bond to form a ribbon extending along the a axis and the aromatic stock effect exists.

Does supplier concentration matter to investors during the COV1D-19 crisis:evidence from China?

The literature shows that investor attention to customer–supplier disclosure increases when suppliers’information arrival is anticipated.Due to the widespread of city lockdowns in China and the implementation of social distancing to control the COVID-19 pandemic,investor attention to potential disruption of the supply chain spikes,leading to a price devaluation for firms with high supplier concentration risk.We find that a higher degree of supplier concentration is related to more serious stock price declines over the short-term and medium-term windows right after the Wuhan lockdown.This result lends support to the argument that the concentration risk of suppliers is a significant consideration for China stock market investors,especially under the potential financial distress at the firm level induced by the COVID-19 crisis.