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PubMed2000

Deficiency of "Thin" Stellar Bars in Seyfert Host Galaxies.

Using all available major samples of Seyfert galaxies and their corresponding closely matched control samples of nonactive galaxies, we find that the bar ellipticities (or axial ratios) in Seyfert galaxies are systematically different from those in nonactive galaxies. Overall, there is a deficiency of bars with large ellipticities (i.e., "thin" or "strong" bars) in Seyfert galaxies compared to nonactive galaxies. Accompanied with a large dispersion due to small number statistics, this effect is strictly speaking at the 2 sigma level. To obtain this result, the active galaxy samples of near-infrared surface photometry were matched to those of normal galaxies in type, host galaxy ellipticity, absolute magnitude, and, to some extent, redshift. We discuss possible theoretical explanations of this phenomenon within the framework of galactic evolution, and, in particular, of radial gas redistribution in barred galaxies. Our conclusions provide further evidence that Seyfert hosts differ systematically from their nonactive counterparts on scales of a few kiloparsecs.

Journal Article↗
PubMed1988

[The chloroquine resistance of Plasmodium falciparum in Vanuatu (1980-1984): appearance, evolution, distribution].

Chloroquine resistance of P. falciparum was studied in Vanuatu from March 1981 to July 1984, with limited means, and a non-systematic procedure; it was first evidenced in 1980. In vivo chloroquine resistance criteria were those established by W. H. O. In vitro testing methods were the standard W. H. O. macro-test and micro-test. 124 in vivo chloroquine resistant cases were seen: 111 cases in hospital (63 R III, 28 R II and 20 R I) and 13 cases in field studies (1 R III, 4 R II and 8 R I). 87 in vitro chloroquine sensitivity tests were carried out. A high failure rate was apparently due to a defective batch of lyophilised culture medium. Out of the 25 isolates successfully tested, 22 showed in vitro chloroquine resistance (88%). Correlation between in vivo and in vitro resistance was good in 13 cases studied by both methods. Moreover, 13 in vitro mefloquine sensitivity tests evidenced a high sensitivity to this drug. Chloroquine resistant malaria thus appears to be extended to the whole country. Its prevalence remains unknown but was estimated at 60% at least in 1984. Moreover, a geographical spread of chloroquine resistance from north to south of the group was evidenced between 1980 and 1984, identical to that of the dramatic increase of P. falciparum incidence at the same period of time. Possible mechanisms of the advent of chloroquine resistance in Vanuatu are discussed.

Adolescent↗
PubMed2002

Is morphology still relevant?

The utility of morphological data in modern systematics has recently been challenged because strong selection pressures are thought to create widespread patterns of convergent evolution at this level. This concern has led to suggestions that morphological data should be excluded either from all analyses or at least from analyses where there is conflict with molecular data. These concerns, however, are generally unwarranted and excluding data is not a defensible strategy for dealing with problems that do exist. We emphasize the importance of empirical responses, such as collecting additional and diverse data and exploring taxa and data set interactions, rather than the implementation of a priori assumptions, to overcoming many of the concerns associated with combining morphological and molecular data. Numerous factors may create biases in both molecules and morphology. While these biases are prevalent enough to cause widespread incongruence, they highlight the importance of combining, rather than separating, data. Morphological data also offer distinct advantages over molecular data, such as the inclusion of fossil taxa, cost-effectiveness and presence of biases different from those in molecular data.

Animals↗
PubMed2006

Development of nuclear gene-derived molecular markers linked to legume genetic maps.

The systematic identification of the orthologous features of related organisms greatly facilitates comparative genomics, including research on genome evolution and comparative genetic mapping. In this study, we selected 274 unique gene sequences for the development of PCR-based genetic markers across fifteen legume genomes, representing six crop or model legume species from the phaseoloid and inverted repeat loss clades (IRLC). DNA sequence analysis demonstrated that 129 of the amplified fragments represented single copy loci across most target diploid genomes. The majority of these markers are intron-spanning (70.5%) and linked to legume genetic maps (85.3%). The markers were grouped into four main categories: (1) intron-spanning relatively conserved, (2) intron-spanning diverged, (3) exon-derived conserved, and (4) exon-derived diverged. The extent of sequence divergence within each category indicates that the corresponding markers may have utility for assessing phylogenetic relationships at different, but overlapping, taxonomic levels. We tested marker performance on genomes that had not been previously sampled, representing 95 different species that span the diversity of the Fabaceae. Phylogenetic analyses support the orthology of amplified sequences, with the notable exception of an ambiguous affiliation of Lotus relative to the IRLC and phaseoloid clades.

Amino Acid Sequence↗
PubMed2004

Instability of the interface between thin fluid films subjected to electric fields.

The effect of an externally applied electric field on the stability of the interface between two thin leaky dielectric fluid films of thickness ratio and viscosity ratio ris analyzed using a linear stability analysis in the long-wave limit. A systematic asymptotic expansion is employed in this limit to derive the coupled nonlinear differential equations describing the evolution of the position of the interface between the fluids and the interfacial free charge distribution. The linearized stability of these equations is determined and the effect of the ratio of the conductivities, dielectric constants, thicknesses, and viscosities on the wavenumber of the fastest growing mode, kmax, and the growth rate of the most unstable mode, smax, is examined in detail. Specific configurations considered in previous studies, such as a perfect dielectric-air interface, leaky dielectric-air interface, etc., emerge as limiting cases from the general formulation developed in this paper. Our results show that the viscosity ratio, mur, does not have any significant effect on kmax for the interface between perfect and leaky dielectric fluids. In marked contrast, however, mur is shown to have a significant effect on the interface between two leaky dielectrics. Increasing mur from 0.1 to 10 could decrease kmax up to a factor of 5. In general, our results show that the presence of nonzero conductivity in either one or both of the fluids has a profound influence on the length-scale characteristic of the linear instability: a reduction even by a factor of 1/50 in the length scale can be effected when compared to the interface between two perfect dielectrics. These predictions could have important implications in pattern formation applications in thin fluid films that employ electric fields. The variation of kmax and smax on the thickness ratio, beta, indicates in general that kmaxalpha(beta-apha), and smaxalpha(beta-theta), where the exponents alpha and theta (both >0) are found to depend only on the ratio of conductivities, and are largely independent of other system parameters.

Journal Article↗
PubMed2002

Herpesvirus genetics has come of age.

The genetic analysis of the large and complex herpesviruses has been a constant challenge to herpesvirologists. Elegant methods have been developed to produce mutants in infected cells that rely on the cellular recombination machinery. Bacterial artificial chromosomes (BACs), single copy F-factor-based plasmid vectors of intermediate insert capacity, have now enabled the cloning of complete herpesvirus genomes. Infectious virus genomes can be shuttled between Escherichia coli and eukaryotic cells. Herpesvirus BAC DNA engineering in E. coli by homologous recombination requires neither restriction sites nor cloning steps and allows the introduction of a wide variety of DNA modifications. Such E. coli-based technology has provided a safe, fast and effective approach to the systematic mining of the information stored in herpesvirus genomes as a result of their intimate co-evolution with their specific hosts for millions of years. Use of this technique could lead to new developments in clinical virology and basic virology research, and increase the usage of viral genomes as investigative tools and vectors.

Animals↗
PubMed2003

Degradation of organic water pollutants through sonophotocatalysis in the presence of TiO(2).

The degradation of 2-chlorophenol and of the two azo dyes acid orange 8 and acid red 1 in aqueous solution was investigated kinetically under sonolysis at 20 kHz and under photocatalysis in the presence of titanium dioxide particles, as well as under simultaneous sonolysis and photocatalysis, i.e. sonophotocatalysis. The influence on the degradation and mineralisation rates of the initial substrate concentration and of the photocatalyst amount was systematically investigated to ascertain the origin of the synergistic effect observed between the two degradation techniques. The evolution of hydrogen peroxide during kinetic runs was also monitored. Small amounts of Fe(III) were found to affect both the adsorption equilibria on the semiconductor and the degradation paths. Ultrasound may modify the rate of photocatalytic degradation by promoting the deaggregation of the photocatalyst, by inducing the desorption of organic substrates and degradation intermediates from the photocatalyst surface and, mainly, by favouring the scission of the photocatalytically and sonolytically produced H(2)O(2), with a consequent increase of oxidising species in the aqueous phase.

Journal Article↗
PubMed2005

DFT study of the monomers and dimers of 2-pyrrolidone: equilibrium structures, vibrational, orbital, topological, and NBO analysis of hydrogen-bonded interactions.

A computational study of the monomers and hydrogen-bonded dimers of 2-pyrrolidone was executed at different DFT levels and basis sets. The above dimeric complexes were treated theoretically to elucidate the nature of the intermolecular hydrogen bonds, geometry, thermodynamic parameters, interaction energies, and charge transfer. The processes of dimer formation from monomers and concerted reactions of double proton transfer were considered. The evolution of geometry, vibrational frequencies, charge distribution, and AIM properties in going from monomers to dimers was systematically followed. The solvent effects upon dimer formation were investigated in terms of the self-consistent reaction field (SCRF Onsager model). For the monomers and three dimers, vibrational frequencies were calculated and the changes in frequencies of the vibrations most sensitive to complexation were discussed. The orbital interactions were shown to lengthen the X-H (X = N, O) bond and lower its vibrational frequency (a red shift). To better understand the nature of the corresponding intermolecular interactions, we performed natural bond orbital (NBO) analysis. Topological analysis of electron density at bond critical points (BCP) was executed for complex molecules using the Bader's atoms in molecules (AIM) theory. The interaction energies were calculated, and the basis set superposition errors (BSSE) were estimated systematically. Satisfactory correlations between the structural parameters, interaction energies, and electron density characteristics at BCP were found.

Journal Article↗
PubMed2003

The adversarial court system and the expert medical witness: 'The truth the whole truth and nothing but the truth?'.

This discussion aims to provide the occasional medical expert witness with background knowledge of the adversarial court system and the role of the medical expert witness within it. The parallel evolution of the adversarial and inquisitorial legal systems has been more out of tradition rather than any systematic review of the effectiveness of one system or the other. Both legal systems have their merits and limitations. Witnesses within the adversarial system are required to present evidence in a structured and highly stylized format consisting of 'evidence in chief' followed by 'cross-examination'. This format is an attempt to exclude unreliable evidence. The medical witness is an 'expert' by means of specialized knowledge not possessed by the general public. This distinction allows the expert medical witness to offer his or her opinion as evidence. There remain several limitations to the expert's evidence and these relate to common knowledge, field of expertise and the 'ultimate issue'. The current practice of selection of expert medical witnesses is seriously flawed with several pressures operating to maximise bias and inaccurate testimony. Doctors should not only anticipate change in this area they should lead reform in this area.

Australia↗
PubMed2000

Symmetry breaking and coarsening in spatially distributed evolutionary processes including sexual reproduction and disruptive selection.

Sexual reproduction presents significant challenges to formal treatment of evolutionary processes. A starting point for systematic treatments of ecological and evolutionary phenomena has been provided by the gene-centered view of evolution which assigns effective fitness to each allele instead of each organism. The gene-centered view can be formalized as a dynamic mean-field approximation applied to genes in reproduction and selection dynamics. We show that the gene-centered view breaks down for symmetry breaking and pattern formation within a population and show that spatial distributions of organisms with local mating neighborhoods in the presence of disruptive selection give rise to such symmetry breaking and pattern formation in the genetic composition of local populations. Global dynamics follows conventional coarsening of systems with nonconserved order parameters. The results have significant implications for the ecology of genetic diversity and species formation.

Alleles↗
PubMed1982

Arguments in favor of precautional treatment of cervical nodes in clinically N0 oral cancer.

Our retrospective and unrandomized clinical study covers 317 squamous cell carcinomas of the oral cavity initially N0 and treated with curietherapy from January 1959 to December 1970. Upon conclusion of the treatment of T, a radical dissection of the neck was performed only on 110 patients (34.7%) and the other 207 were not submitted to surgery. The incidence of N0 N+ cases was 27.3% (30/110). The clinical evolution showed that in the group not submitted to radical dissection 53 of 179 cases (29.6%) with adequate follow-up had lymph nodal relapses; 15/69 of these were initially T1 (21.7%) and 38/110 initially T2,3 (34.5%). The data concerning clinical evolution and analysis of the survival curves for the 2 groups supply arguments in favor of the systematic treatment of the lymphatic areas of the neck in initially N0 oral carcinomas.

Humans↗
PubMed2006

inGeno--an integrated genome and ortholog viewer for improved genome to genome comparisons.

BACKGROUND: Systematic genome comparisons are an important tool to reveal gene functions, pathogenic features, metabolic pathways and genome evolution in the era of post-genomics. Furthermore, such comparisons provide important clues for vaccines and drug development. Existing genome comparison software often lacks accurate information on orthologs, the function of similar genes identified and genome-wide reports and lists on specific functions. All these features and further analyses are provided here in the context of a modular software tool "inGeno" written in Java with Biojava subroutines. RESULTS: InGeno provides a user-friendly interactive visualization platform for sequence comparisons (comprehensive reciprocal protein--protein comparisons) between complete genome sequences and all associated annotations and features. The comparison data can be acquired from several different sequence analysis programs in flexible formats. Automatic dot-plot analysis includes output reduction, filtering, ortholog testing and linear regression, followed by smart clustering (local collinear blocks; LCBs) to reveal similar genome regions. Further, the system provides genome alignment and visualization editor, collinear relationships and strain-specific islands. Specific annotations and functions are parsed, recognized, clustered, logically concatenated and visualized and summarized in reports. CONCLUSION: As shown in this study, inGeno can be applied to study and compare in particular prokaryotic genomes against each other (gram positive and negative as well as close and more distantly related species) and has been proven to be sensitive and accurate. This modular software is user-friendly and easily accommodates new routines to meet specific user-defined requirements.

Base Sequence↗
PubMed1988

Cerebromeningeal hemorrhage. Analysis of autopsies performed over a 10-year period.

A study was conducted on the medical records of 353 patients who died of a subarachnoid hemorrhage (SAH) and who were submitted to autopsy over the last 10 years. SAH was associated with arterial hypertension in 180 (51%) cases, with ruptured aneurysms in 102 (28.9%), and with other pathologies in 71 (20.1%). The patients with hemorrhage associated with arterial hypertension were mostly males, and those with hemorrhage due to aneurysms were mostly females. Of the patients with aneurysms, 36 (35.3%) had aneurysms in the anterior communicating artery, 30 (29.4%) in the internal carotid artery, and 23 (22.6%) in the middle cerebral artery. Among the patients with aneurysms who suffered rebleeding and vasospasm, 59.1% and 61.5%, respectively, were classified as grade I and II upon admission, and all evolved toward grade IV after these complications. Vasospasm predominated from the 3rd to the 10th day after hemorrhage, and rebleeding from the 9 to 16th day and both were most frequent among patients with aneurysms of the anterior communicant artery. Sixty eight percent of the patients with aneurysms died during the first 9 days after hemorrhage. Because of our conduct was to operate systematically late, a considerable number of patients lost the opportunity to be treated surgically with possible favorable evolution due to vasospasm or rebleeding.

Adolescent↗
PubMed2002

Cryptic designs on the peppered moth.

In a provocative recent book, Jonathan Wells (2000) decries what he discerns as a systematic pattern in how introductory biology textbooks "blatantly misrepresent" ten routinely cited examples offered as evidence for evolution. Each of these examples, according to Wells, is fraught with interpretive problems and, as such, textbooks that continue to use them should at the very least be accompanied by warning labels. The following essay critiques his reasoning with reference to one of these examples, the phenomenon of industrial melanism. After criticizing Wells's specific argument, the essay draws several conclusions about the nature of science lost in his account.

Adaptation, Physiological↗
PubMed1978

[Psychology of relations as a theoretical concept of medical psychology and psychotherapy].

This paper presents the theoretical concept of the "psychology of relations" (A.F. Lasurski, V.N. Myasistchev) which forms the basis for studying the personality of a patient and for finding a suitable treatment of nervous and mental disorders by psychological methods. The author shows that there is theoretical agreement between the psychology of relations and the philosophy of dialetical materialism and Pavlov's theory of conditioned reflexes. Also discussed in this paper is the concept's relation to clinical psycho-neurology, its orientation toward considering personality as a system, as well as the recognition of the primacy of the conscious over the unconscious. Prospects for an evolutional and ontogenetic approach to an analysis of the system of relations and the need for elaborating systematized work programs determined by the investigative goal to be achieved are also considered by the author in his present paper.

Adolescent↗