Hydrodynamic behaviour of Nummulites: implications for depositional models

Large benthic foraminifers are considered to be good indicators of shallow marine carbonate environments in fossil series. Over the last 50 years, the palaeoenvironment of Tertiary Nummulites accumulations has been a matter of debate, particularly because of difficulties in interpreting these deposits, and in this way, the absence of analogues in present-day seas does not help. The aim of this paper is to insight the different ways Nummulites tests and clasts may accumulate according to their hydrodynamic behaviour. Based on experimental measurements and on SEM observations, it appears that the high primary skeletal porosity of Nummulites made them easily transportable. The calculated threshold shear velocities confirm that large-sized Nummulites can be moved by weak wave-driven currents. This peculiar hydrodynamic behaviour of Nummulites could explain the diversity of depositional models. Depending on local hydrodynamic conditions, autochthonous Nummulites deposits can be preserved as in situ winnowed bioaccumulations or be accumulated offshore, onshore or alongshore, away from the original biotope.     

A New Statistical Goodness-of-Fit Test Based on Graphical Representation

A statistical goodness-of-fit test, based on representing the sample observations by linked vectors, is developed. The direction and the length of the linked vectors are defined as functions of the expected values of the order statistics and sample order statistics, respectively. The underlying method can be used to test distributional assumptions for any location-scale family. A test statistic Q_n is introduced and some of its properties are studied. It is shown that the proposed test can be generalized to test if two or more independent samples come from the same distribution. The test procedure provides a graphical method of identifying the true distribution when the null hypothesis is rejected.     

Phenotypic Correlation: Its Estimation and Testing Significance

Plant scientists often assess correlation coefficients to develope a selection strategy for better plant type. They generate data on the desired traits on several genotypes grown in a randomized complete block design. Using the data from such experiments, this paper presents the asymptotic standard error of an estimate of phenotypic correlations coefficient and a test of significance. The method is illustrated using data on chickpea crop.     

Paradoxical effect of sudan III on the in vivo and in vitro genotoxicity elicited by 7,12-dimethylbenz(a)anthracene

Effect of the induction of drug metabolizing enzymes by Sudan III on the in vivo and in vitro genotoxicity elicited by 7,12-dimethyl-benz(a)anthracene (DMBA) was investigated. A significant suppression of DMBA-induced micronucleated reticulocytes was observed in C57BL/6 mice treated with Sudan III intraperitoneally for 3 or 5 days before injection of the DMBA. However, the preincubation of DMBA with hepatic microsomes from Sudan III-treated rats caused a marked increase in the in vitro mutagenicity in the Ames assay, paradoxically. Sudan III was found to induce CYP 1A1, 7-ethoxycoumarin O-deethylase activity as well as both UDP-glucuronyl transferase and glutathione S-transferase activities. The increase of mutagenicity of DMBA observed in the Ames assay using hepatic microsomes from Sudan III-treated rats was inhibited by the addition of uridine 5′-diphosphoglucuronic add or reduced glutathione with cytosol. Mutagenic metabolites of DMBA formed by CYP1A1 appeared to be effectively detoxified by these phase II enzymes. The results of this study suggest that Sudan III-induced prevention of in vivo mutagenesis is due to the induction of both CYP 1A1 and detoxifying phase II enzymes. The induced CYP1A1 may accelerate formation of active metabolic intermediates, but phase II enzymes are also induced and detoxify these intermediates to inactive metabolites. This would reduce residence time of the carcinogen in the body and the time of exposure to active metabolites for target organs.