SYSTEMATICS AND TAXONOMY OF EOCENE TOMISTOMINE CROCODYLIANS FROM BRITAIN AND NORTHERN EUROPE

Abstract:  The holotype of Dollosuchus dixoni (Owen) from the Early–Middle Eocene Bracklesham Beds of England is a set of mandibular fragments that cannot be distinguished from corresponding parts of other longirostrine crocodylians. An isolated humerus from the Bracklesham Beds is consistent with a gavialoid, but it cannot be referred to the holotype of D. dixoni . The name Dollosuchoides densmorei is established for the well-preserved skull and skeleton of a tomistomine from the Middle Eocene of Belgium that had been referred to D. dixoni . It can be clearly distinguished from the basal tomistomine ' Crocodilus ' spenceri Buckland from the Lower Eocene of England, which cannot be referred to Dollosuchoides and is provisionally referred to Kentisuchus Mook. Although basal within Tomistominae, Dollosuchoides is more closely related to Tomistoma than to Kentisuchus .     

Thyreophoran vertebrae from the Callovian (Middle Jurassic) of the Vaches Noires cliffs (Normandy,France), with remarks on the dinosaur assemblage from the Vaches Noires

Two associated incomplete thyreophoran dorsal vertebrae from the Callovian Marnes de Dives Formation of the Vaches Noires cliffs, on the Normandy coast, are referred to an indeterminate stegosaur that appears to be different from Lexovisaurus, previously reported from the Callovian of western France. These vertebrae are the first evidence of thyreophorans from the Vaches Noires and complement the dinosaur assemblage from this locality, which hitherto consisted of several theropod taxa and an indeterminate sauropod. The dinosaur record from the Vaches Noires is heavily dominated by theropods and this imbalance is difficult to explain. A possible explanation may be that the dinosaur sample from the Vaches Noires is too small to be statistically significant and representative of the original faunal assemblage from which it is derived.     

How should we normalize electromyograms obtained from healthy participants? What we have learned from over 25 years of research

Electromyograms (EMGs) need to be normalized if comparisons are sought between trials when electrodes are reapplied, as well as between different muscles and individuals. The methods used to normalize EMGs recorded from healthy individuals have been appraised for more than a quarter of a century. Eight methods were identified and reviewed based on criteria relating to their ability to facilitate the comparison of EMGs. Such criteria included the magnitude and pattern of the normalized EMG, reliability, and inter-individual variability. If the aim is to reduce inter-individual variability, then the peak or mean EMG from the task under investigation should be used as the normalization reference value. However, the ability of such normalization methods to facilitate comparisons of EMGs is questionable. EMGs from MVCs can be as reliable as those from submaximal contractions, and do not appear to be affected by contraction mode or joint kinematics, particularly for the elbow flexors. Thus, the EMG from an isometric MVC is endorsed as a normalization reference value. Alternatively the EMG from a dynamic MVC can be used, although it is recognized that neither method is guaranteed to be able to reveal how active a muscle is in relation to its maximal activation capacity.     

A note on the interpretation of perseveration in discrimination

The effect of one judgment upon the next judgment in a discrimination situation is considered to be the result of two types of perseveration. One arises from the judgment itself. The other results from a persistence, from one trial to the next, of a transient bias. It is shown that the resulting perseveration can then be a function of the difficulty of the first of the pair of choices. Expressions are derived from which the extent of each effect can be measured from observed proportions of responses.     

The impossibility of estimating a negative binomial clustering parameter from presence-absence data: a comment on He and Gaston

An important problem is to infer the abundance of a species in an area from its presence or absence in the cells of a uniform grid. If the abundance is assumed to be distributed over cells according to a negative binomial model, a value of the clustering parameter k is needed to infer the abundance. It is shown that, despite a proposal in the literature, k cannot be estimated from presence-absence data but must be given from outside information.     

对(艹孟)烷-3,8-二醇的合成与应用研究进展

对(艹孟)烷-3,8-二醇是一种具有生物活性的化合物,主要来源于柠檬桉精油,可直接用于香水、杀虫剂和药品等.通常采用化学和生物化学的方法合成对(艹孟)烷-3,8-二醇,以替代从柠檬桉叶油分离得到的天然产品.以香茅醛为原料通过Prins环缩合和水解,或者通过Solanum aviculare悬浮培养方式进行生物转化得到对(艹孟)烷-3,8-二醇;通过薄荷醇的氧化,或者以2-丁烯醛为原料与甲基锂、NaClO2等试剂经过较长步骤也可合成对(艹孟)烷-3,8-二醇.对(艹孟)烷-3,8-二醇可应用于制造驱虫剂、凉味剂、药物或者化妆品的添加剂以及海水防护涂料添加剂等.     

Direct spectrophotometric observation of an acyl-enzyme intermediate in elastase catalysis.

A technique is presented that is useful for selecting conditional-lethal mutants of mycoplasma cells and viruses. The method is based on growing mycoplasma on Millipore filters. Mutants can be isolated directly from filters seeded with mycoplasma. The filters can be transferred from condition to condition, acting as its own “master” and “replica” template. Virus mutants from the non-lytic Mycoplasma Group L1 and L2 viruses can also be picked from filters seeded with infected cells. This method is analogous to classical “replica plating” which is not a practical technique for mycoplasmas.     

Comparison of definitions of the lag phase and the exponential phase in bacterial growth.

Different definitions for the lag time and of the duration of the exponential phase can be used to calculate these quantities from growth models. The conventional definitions were compared with newly proposed definitions. It appeared to be possible to derive values for the lag time and the duration of the exponential phase from the growth models and differences between the various definitions could be quantified. All the different values can be calculated from the growth parameters microm, lambda and alpha. Therefore, it appeared to be unnecessary to use complicated mathematical equations; simple equations were adequate. For the Gompertz model the conventional definition of the lag time did not differ appreciably from the newly proposed definition. The end-point of the exponential phase and thus the duration of the exponential phase differed considerably for the two definitions. For the logistic model the two definitions lead to considerable differences for all quantities. It is recommended that the conventional definition is used for calculating the lag time. For the duration of the exponential phase it is recommended that the new definition is used. The value can be calculated, however, directly from the conventional growth parameters.     

Detecting Small Amounts of Gene Flow from Phylogenies of Alleles

The method of coalescents is used to find the probability that none of the ancestors of alleles sampled from a population are immigrants. If that is the case for samples from two or more populations, then there would be concordance between the phylogenies of those alleles and the geographic locations from which they are drawn. This type of concordance has been found in several studies of mitochondrial DNA from natural populations. It is shown that if the number of sequences sampled from each population is reasonably large (10 or more), then this type of concordance suggests that the average number of individuals migrating between populations is likely to be relatively small (Nm less than 1) but the possibility of occasional migrants cannot be excluded. The method is applied to the data of E. Bermingham and J. C. Avise on mtDNA from the bowfin, Amia calva.     

Aeolid opisthobranch molluscs (Glaucidae) from the Indian Ocean and the south-west Pacific

Eight aeolid opisthobranch molluscs of the subfamilies Facelininae, Favorininae, and Herviellinae are reported from Tanzanian waters, and two species from Northwestern India. New records from Queensland, Australia greatly extend the range of two species reported from Tanzania. Phidiana militaris (Alder & Hancock) and P. indica (Bergh) are shown to be distinct and a species from New Zealand, originally identified as P. militaris , is shown to be new. P. bourailli (Risbec), previously reported only from New Caledonia, is described from Tanzania, as is a new species of Phidiana. Favorinus japonicus Baba is reported from Tanzania, the first published record outside Japan, a new species of Godiva is described from Tanzania and Queensland, and three new species of Sakuraeolis are described, one from India and two from Tanzania. A new species of Herviella is described from Tanzania.     

ONTOGENY OF CHICKEN HEMOGLOBIN. III. IMMUNOLOGICAL STUDY OF THE HETEROGENEITY OF HEMOGLOBIN IN DEVELOPMENT

By applying the double diffusion technique of Ouchterlony and the immunoelectrophoresis, sequence in the appearance of antigens reactive with antisera against HbCOs from 5-day embryos and adult chickens, and the major component of adult HbCO in the course of chicken development has been studied.
Antigenic components reacting to antiserum against HbCO from 5-day embryos have been detected throughout development. Three globin-like components specific to early embryos are detectable in embryos to 2 days of incubation. Two Hb components are detectable in embryos from 3 to 5 days of incubation; one is apparently specific to embryos, while the other seems to be somewhat different from adult Hb. After 6 days of incubation only one adult Hb component is detectable.
Antigenic components reacting to antiserum against HbCO from adults have also been detectable throughout embryonic life. One globin-like component specific to early embryos can be found in embryos to 2 days of incubation. One or two Hb components which are probably specific to embryos can be detected in embryos from 3 to 5 days of incubation. After 6 days of incubation one adult Hb component is detectable, while one globin-like component specific to adults can be found after 15 days of incubation. Further, the other globin-like component is detectable after 3 days of incubation.
Antigenic components reacting to antiserum against the major component of adult HbCO have been detected throughout development; one which seems to be somewhat different from either adult Hb components can be found in embryos from 2 to 5 days of incubation, while the other which is identical with the major component of adult Hb is detectable after 6 days of incubation.     

Disease

This paper examines what it is for a condition to be a disease. It falls into two sections. In the first I examine the best existing account of disease (as proposed by Christopher Boorse) and argue that it must be rejected. In the second I outline a more acceptable account of disease. According to this account, by disease we mean a condition that it is a bad thing to have, that is such that we consider the afflicted person to have been unlucky, and that can potentially be medically treated. All three criteria must be fulfilled for a condition to be a disease. The criterion that for a condition to be a disease it must be a bad thing is required to distinguish the biologically different from the diseased. The claim that the sufferer must be unlucky is needed to distinguish diseases from conditions that are unpleasant but normal, for example teething. Finally, the claim that for a condition to be a disease it must be potentially medically treatable is needed to distinguish diseases from other types of misfortune, for example economic problems and legal problems.     

Three new species of Bryconamericus (Ostariophysi: Characidae) from Colombia and a diagnosis for the genus

Three new fish species are described: Bryconamericus dahli from the basins of the Patia and Mira rivers; B. ichoensis from Chaparraido Creek, the upper Atrato River basin, and B. galvisi from upper Putumayo River. Bryconamericus dahli can be distinguished from other Bryconamericus species by body depth and the larger head. B. dahli is similar to B. caucanus, but can be distinguished by the number of anal fin rays, head width and maxilla. Bryconamericus ichoensis can be distinguished by its small size, absence of a spot on the caudal peduncle, and generally 27 to 30 anal fin rays. B. ichoensis may be closely related to B. multiradiatus, but can be distinguished by the number of unbranched rays in the dorsal, pectoral and pelvic fins, the number of predorsal scales, body depth, etc. Bryconamericus galvisi, can be distinguished from other species of Bryconamericus by its single peduncle spot, high branched anal fin ray, the lateral line scales count, and elongated body. This species is similar to B. caucanus and can be distinguished by the number of teeth on the maxilla and by the number of vertebrae. The genus Bryconamericus is a natural and valid group, which is related to Hemibrycon. Moreover the Knodus and Eretmobrycon are synonym of Bryconamericus.     

An idea of community and its discontents: towards a more reflexive sense of belonging in multicultural Britain

In many less developed countries economic development is not in conformity with the actual level of consumption. In part this is to be explained by the huge informal sector that is not included in official statistics. However, using Suriname as a case study, it is argued in this article that a significant part of the discrepancies can be explained from private household transfers from The Netherlands. Migration is not a loss in all respects, but sometimes an asset. In contrast the remittances from temporarily migrated workers, the transfers from people constituting a transnational community cannot be taken for granted. This private family aid expresses personal commitments at the primordial level, and is therefore a kind of moral capital. Depending on the size of the migrated community and the moral commitments of their members, these transfers constitute a net surplus from the former metropolis to the periphery.     

Protein disulphide-isomerase of chick-embryo tendon.

Protein disulphide-isomerase can be partially purified from the high-speed-supernatant fraction of extensively disrupted chick-embryo tendon tissue. The catalytic properties of the preparation resemble those of the enzyme from mammalian liver. Gel electrophoresis and isoelectric focusing show the enzyme to be very acidic, with pI 4.4 +/- 0.3. Gel filtration indicates an Mr for the active enzyme of 140 000. The enzyme can be partially purified by preparative gel filtration or isoelectric focusing, but its limited stability has prevented purification to homogeneity; active fractions from both gel filtration and isoelectric focusing show two major polypeptide components by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The major polypeptides present in partially purified preparations have Mr 45 000 and 55 000; the latter band co-distributes with the enzyme activity in fractionations by both gel filtration and isoelectric focusing. The subcellular location of the enzyme cannot be established from work on homogenates of whole tissue, which are extensively disrupted. In homogenates from isolated tendon cells, the enzyme is located in a vesicle fraction that is excluded from Sepharose 2B but is of low density and can only be sedimented at very high speeds. This fraction is identified as deriving from the endoplasmic reticulum on the grounds of marker-enzyme studies and electron microscopy.     

The ultrastructure and taxonomy of the Chrysophyceae and Prymnesiophyceae (Haptophyceae): a survey with some new observations on the ultrastructure of the Chrysophyceae

Information on the internal structure of the Chrysophyceae is reviewed and some new data are presented. From these a model has been constructed which represents the combination of features constructed to be the basic pattern of cell structure in this group. A brief review is given of modern research, which demonstrates that the choanoflagellates should be removed not only from the Chrysophyccae but also from the plant kingdom. The organization of the Prymnesiophyceae classis nova (= Haptophyceae) is compared with that of the Chrysophyceae, and the relationship of both groups to the Xanthophyccae, Phaeophyceac anti Bacillariophyceae is considered. This leads to the conclusion that the Prymnesiophyceae must be considered as a class separate from the Chrysophyceae. Removal of the Prymnesiophyceae and choanoflagellates from the Chrysophyceae leaves a largely homogeneous and monophyletic group, though the family Pedinellaceae appears to have a unique organization and may be found to be separated from the Chrysophyccae by a phyletic distance at least as great as that between the remaining classes of heterokont algae. It is suggested that this family should occupy a more isolated position in the Chrysophyceae than at present, possibly in a separate order Pedinellales.     

Prediction of mean and variance of hybrids and of lines that can be derived from a random mating population

Summary A method is presented to estimate, from a two-factor crossing design including self-fertilization, mean and variance of lines and hybrids that can be derived from a random mating population. The derivation is only valid in the absence of epistasis. From such an estimation, it is possible to derive the expected value of the best lines and of the best hybrids that can be derived from a population.     

Somatic embryogenesis and in vitro flowering inBrassica nigra

Summary This report describes a protocol for regeneration ofBrassica nigra in vitro from unorganized callus to a highly differentiated stage of flowering. Callus is initiated from seedling hypocotyl, and root explants and plantlets are obtained via somatic embryogenesis. Shoot cultures can be established from these plantlets. These shoots can either be induced to flower in vitro or rooted to produce plants which flower ex vitro. Each stage of development is marked with a specific growth regulator requirement. This has potential as a model system to understand the cellular and molecular mechanisms involved in morphogenesis, and it can be used to understand the mechanism of change of phase from vegetative to reproductive. An advantage of this system is that in vitro flowering can be obtained repeatedly in the shoots raised from the axillary buds of the flowering shoots. The protocol can also be used to procureB. nigra gametes under aseptic condition.     

BOOK REVIEWS

The relative radiation hazards from early and delayed fallout following a nuclear attack have been reviewed. It is indicated that the hazard to life from whole-body gamma irradiation from early fallout far outweighs the hazard from radioactive contamination of food. Nevertheless, because of the possible effects of iodine-131, the consumption by infants of fresh milk from animals which have ingested contaminated fodder should be avoided if possible during the first few weeks after attack. During the same period, water from covered supplies should be used in preference to that from open reservoirs. It is more important, however, to alleviate hunger and thirst in both man and animal than to prevent the temporary ingestion of food which may be contaminated by fallout.     

Isolation of Three Crystalline Proteins from Beef Liver After Partial Purification by Acetone Fractionation

The isolation of three proteins in crystalline form from ground beef liver is described. These proteins are FTBL protein (Arch. Biochem. Biophys. 188, 251–265 (1978), crotonase, and catalase. Crotonase is isolated by crystallization from a 32 acetone extract of the ground liver. FTBL protein and catalase can subsequently be isolated from the same extract. For optimal yield and ease of isolation, FTBL protein is isolated from a 46.5% acetone extract from which catalase can subsequently be crystallized by dialysis.

The isolation of FTBL protein as well as the isolation of catalase involves a preliminary fractional precipitation and solution before crystallization can be achieved. Isopropanol can be substituted for acetone in the isolation of the above three proteins and in the case of catalase, results in an exceptionally high yield.

Methods for the recrystallization of the proteins are presented and the role of organic solvents in recrystallization is discussed.