On chains of related sets

IfK is a partition of a setK which is partially ordered by the relationR andR is a collection of pairs of sets ofK such that the sets of each pair are related byR in the sense of Rashevsky, thenR is a relation which partially ordersK. Necessary and sufficient conditions thatK be a chain are obtained, and ifK is a chain under these conditions, it is shown thatK is unique.     

Fixation probabilities and effective population numbers in diploid populations with overlapping generations

A finite diploid population, observed at times t = 0, 1, 2,…, is studied. An individual is said to be in age group i at time t if its age is between i and i + 1 units at that time, where i ? 1. It is assumed that the number of individuals in a particular age-sex class is the same for every t and that the probability that a male offspring was produced by a mating of a male in age group i and a female in age group j is p_ij^m (with a corresponding probability p^f_ij for a female offspring), regardless of when the individual is born. The probability of ultimate fixation of an allele A₁ and the inbreeding effective number, for large populations, is calculated under the further assumptions that A₁ is neutral and that mating is random, given the ages of the mates.     

Paraspinibarbus,a new genus of cyprinid fishes from the Red River basin

Paraspinibarbus, a new and monotypic genus, is erected forSpinibarbus macracanthus Pellegrin et Chevey, 1936, a cyprinid from the Red River basin. It is characterized by a procumbent predorsal spine and a very thick lower lip with a continuous postlabial groove.Balantiocheilus hekouensis Wu, 1977 is a junior subjective synonym ofParaspinibarbus macracanthus. A lectotype is designated forS. macracanthus.     

Justice to Trichostrongylus longispicularis Gordon, 1933 (Nematoda: Trichostrongylidae)

Summary The literature on Trichostrongylus longispicularis Gordon, 1933 and T. lerouxi Biocca, Chabaud & Ghadirian, 1974 is critically reviewed. It is concluded that T. longispicularis is a valid species and that T. lerouxi is a synonym. T. longispicularis is defined and a neotype is designated.     

Proposed validation of the specific namescrenatus Bruguière, 1789, andrenggeri Oppel, 1863 (Class Cephalopoda,Order Ammonoidea) from the Oxfordian stage of the upper jurassic

Ammonites crenata Bruguière (1789) is one of the oldest species names used in modern ammonite taxonomy. This is a nomen dubium that is probably a synonym of what modern authors callCreniceras renggeri (Oppel 1863), a common species of the early Oxfordian.Ammonites crenatus Bruguière in Oppel (1863) is a stratigraphically junior taxon of the middle Oxfordian. Nevertheless, there is a possibility, however improbable it may be, thatAmmonites crenata Bruguière andAmmonites crenatus Oppel are synonyms. Therefore it is proposed here to retain the current usage of the namescrenatus Bruguière emend. d’Orbigny (1847) andrenggeri Oppel.     

Melogonimus rhodanometra n. g., n. sp. (Digenea: Ptychogonimidae) from the elasmobranch Rhina ancylostoma Bloch & Schneider (Rhinobatidae) from the southeastern coastal waters of Queensland,Australia

The new genus Melogonimus is defined and adults of its type-species, M. rhodanometra n. sp., are described from Rhina ancylostoma from Moreton Bay, Queensland. This is the first record of a digenean from this host species. It is argued that metacercariae from the portunid crab Portunus pelagicus from Hervey Bay, off Queensland, belong to M. rhodanometra. The definition of the family Ptychogonimidae is amended, and a key to its two genera is given. Melogonimus is characterised by a smooth genital atrium wall, a large sinus-organ, a large muscular seminal vesicle, a weakly developed pars prostatica, a pre-testicular uterus and confluent post-testicular vitelline fields.     

Complete Genome Sequence of Vibrio parahaemolyticus Bacteriophage vB_VpaM_MAR

Vibrio parahaemolyticus is a major pathogen that is mainly associated with seafood and is a global food safety issue. Our objective was to isolate and completely sequence a specific phage against this bacterium. Phage vB_VpaM_MAR is able to lyse 76% of the V. parahaemolyticus strains tested. MAR belongs to the Myoviridae family and has a genome comprised of double-stranded DNA with a size of 41,351 bp, a G+C content of 51.3%, and 62 open reading frames (ORFs). Bioinformatic analysis showed that phage MAR is closely related to Vibrio phages VHML, VP58.5, and VP882 and Halomonas aquamarina phage ΦHAP-1.     

The A1Ao ATPase from Methanosarcina mazei: Cloning of the 5′ End of the aha Operon Encoding the Membrane Domain and Expression of the Proteolipid in a Membrane-Bound Form in Escherichia coli

Three additional ATPase genes, clustered in the order ahaH, ahaI, and ahaK, were found upstream of the previously characterized genes ahaECFABDG coding for the archaeal A₁A_o ATPase from Methanosarcina mazei. ahaH, the first gene in the cluster, is preceded by a conserved promoter sequence. Northern blot analysis revealed that the clusters ahaHIK and ahaECFABDG are transcribed as one message. AhaH is a hydrophilic polypeptide and is similar to peptides of previously unassigned function encoded by genes preceding postulated ATPase genes in Methanobacterium thermoautotrophicum and Methanococcus jannaschii. AhaI has a two-domain structure with a hydrophilic domain of 39 kDa and a hydrophobic domain with seven predicted transmembrane α helices. It is similar to the 100-kDa polypeptide of V₁V_o ATPases and is therefore suggested to participate in proton transport. AhaK is a hydrophobic polypeptide with two predicted transmembrane α helices and, on the basis of sequence comparisons and immunological studies, is identified as the proteolipid, a polypeptide which is essential for proton translocation. However, it is only one-half and one-third the size of the proteolipids from M. thermoautotrophicum and M. jannaschii, respectively. ahaK is expressed in Escherichia coli, and it is incorporated into the cytoplasmic membrane despite the different chemical natures of lipids from archaea and bacteria. This is the first report on the expression and incorporation into E. coli lipids of a membrane integral enzyme from a methanogens, which will facilitate analysis of the structure and function of the membrane domain of the methanoarchaeal ATPase.     

A note on the structure of system state spaces and its implications on the existence of non-repeatable experiments

The implication of state space structure on the existence of a repeatable experimentE designed to determine if a states∈L has propertyP or notP is investigated. It is shown that if a state spaceL is connected, then no experimentE is repeatable. This formalism is used to demonstrate that if a propertyP has an associated set of points inL which is dense with dense complement inL, then there exists no repeatable experimentE which can be used to test whethers has propertyP or notP. Other consequences of this formalization are discussed.     

On a formal definition of organization

A mathematic definition is proposed to account for the intuitive features of what is usually meant by organization. To account for both functional and structural aspects of organization the rate at which information content of a system changes in time is examined. It can be shown that Shannon's expression for ambiguity in a channel has two different meanings according to whether one is interested in the information transmitted in the channel or in the information transmitted to the observer from a whole system in which the channel is a part of a redundant communication network. This was applied in a previous work to show that the effects of noise on the information content H of a system result in two kinds of ambiguities, “autonomy-producing” and “destructive” leading to increase and decrease in H, respectively. By making use of this observation and Shannon's definition of redundancy R, a single equation for $\text{d}\text{H}\text{dt}$ is proposed to define organization on the basis of a kinetics of change of information content of a system under the effects of environmental noise-producing factors accumulated in time. It is shown how these factors, obviously responsible for a decrease in H, i.e. a “disorganizing” effect, can be responsible also—under certain conditions and up to a certain time or “dose” of noise—for an initial increase in H interpreted as a process of “self”-organization. The autonomy-producing ambiguity is expressed by a term of decrease in redundancy, while a second term in the equation, of decrease in maximum-non-redundant-information content expresses the destructive ambiguity. A given organization is defined at least by three parameters, which determine the main features of its characteristic function H(t). One of them is the initial information content H₀ and has a structural meaning. A second parameter, with a dimension of time, has the meaning of a functional reliability, related to the overall resistance of the system to noise-producing factors. The third parameter, namely the initial redundancy R₀, is both structural and functional in character, since structural redundancy is known to help insure reliability. Various conditions on these parameters lead to various kinds of organizations, with and without self-organizing properties.     

A simple proof that certain quantities are independent of the geographical structure of population

This paper gives a proof that certain quantities are independent of the geographical structure of a population. The quantities are: (1) the fixation probability of a mutant; (2) the sum of the quantity x(1 ? x), where x is the mutant frequency, while the mutant is segregating; and (3) the quantity x(1 ? x) summed over the generations during which the gene frequency in the whole population assumes a specified value. The independence of geographical structure for the latter two quantities is not exact if there is selection, but is a close approximation.The model is a geographically structured version of Moran's haploid overlapping generation model. The population consists of colonies connected genetically by migration. Each individual has the same negative exponential lifetime distribution. When an individual dies, it is immediately replaced by an individual born in the same colony with a probability proportional to the frequency and fitness of the type giving birth. In a diploid population the quantity x(1 ? x) is proportional to the heterozygosity.     

Determination of Dynamical Heterogeneity from Dynamic Neutron Scattering of Proteins

Motional displacements of hydrogen (H) in proteins can be measured using incoherent neutron-scattering methods. These displacements can also be calculated numerically using data from molecular dynamics simulations. An enormous amount of data on the average mean-square motional displacement (MSD) of H as a function of protein temperature, hydration, and other conditions has been collected. H resides in a wide spectrum of sites in a protein. Some H are tightly bound to molecular chains, and the H motion is dictated by that of the chain. Other H are quite independent. As a result, there is a distribution of motions and MSDs of H within a protein that is denoted dynamical heterogeneity. The goal of this paper is to incorporate a distribution of MSDs into models of the H incoherent intermediate scattering function, $I\left(Q,t\right)$, that is calculated and observed. The aim is to contribute information on the distribution as well as on the average MSD from comparison of the models with simulations and experiment. For example, we find that simulations of $I\left(Q,t\right)$ in lysozyme are well reproduced if the distribution of MSDs is bimodal with two broad peaks rather than a single broad peak.     

Place du scanner dans l’imagerie de l’hyperparathyroïdie primaire

Primary hyperparathyroidism is a biological diagnosis. The reference treatment is surgery. When minimally invasive surgery is considered, it is recommended to perform a cervical ultrasound and a scintigraphic examination to localize the hypertrophied parathyroid glands. The multiphasic scanner (4D CT) is a very effective examination to detect and locate precisely the parathyroid adenomas. The study of densities makes it possible to differentiate the adenoma from the thyroid and the lymph nodes that are the differential diagnoses. Without injection, the adenoma is more hypodense than the thyroid with a threshold set at 75 UH. On the early phase after injection, the adenoma appears very hypervascularized with a density > 114 UH. The ganglion appears hypovascularized with a density < 114 UH. In the late phase, there is a decrease in the density within the adenoma, while density within the ganglion increases. The parathyroid scan is indicated in case of negativity or discordance of the couple ultrasound scintigraphy. It is also strongly recommended, in case of persistence or recurrence of hyperparathyroidism after surgery, as well as to better study a parathyroid ectopy.     

Identification and characterization of kraken,a gene encoding a putative hydrolytic enzyme in Drosophila melanogaster

Kraken, a novel Drosophila gene isolated from a 4–8-h-old Drosophila embryo cDNA library, shows homology to a family of serine hydrolases whose common feature is that they all catalyse breakage of substrates with a carbonyl-containing group. It is a single-copy gene with at least two introns and maps to position 21D on polytene chromosomes. kraken is a member of a conserved gene family. Messenger RNA of kraken is expressed ubiquitously in early embryogenesis. Later, it is concentrated in the foregut and the posterior midgut primordium. Towards the end of embryogenesis, expression of kraken is confined to the gastric caeca. During the third-instar larval stage, kraken is expressed at low levels in the gastric caeca and parts of the gut, and at higher levels in the fat body. We suggest a role for Kraken in detoxification and digestion during embryogenesis and larval development.     

A phylogenetic study of the antenna cleaner in Formicidae,Mutillidae, and Tiphiidae (Insecta,Hymenoptera)

Summary The morphology of the tibio-tarsal antenna cleaner (strigilis) of 30 species of Formicidae, 14 species of Mutillidae and 9 species of Tiphiidae was investigated and is described comparatively. In Formicidae, there is a common type of strigilis. The spur has a posterior-dorsal comb and its anterior side is covered with squamae, which usually form a brush. Posteriorly, the basitarsal notch bears a comb and anteriorly specialized paddle-shaped hairs. These characters may be apomorphic for Formicidae. In several Ponerinae and in Myrmecia there is also a velum on the spur. In two species of ants which are strongly parasitic (Teleutomyrmex schneideri and Anergates atratulus ) there are reduced antenna cleaners. Mutillidae (except Myrmosa) have another common type of strigilis: the spur bears a velum with a smooth rim and a clear apex with two rows of teeth. The notch in the basitarsus is usually deeper than that of ants; there is a comb, but no paddle-shaped hairs. The strigilis of Myrmosa females has no velum but there are two prominent rows of teeth on the spur. In the male, the velum is reduced to a slender strip. In Tiphiidae the antenna cleaners show considerable diversity. In Methocha the spur bears a comb but no velum; the spur of Tiphia has a velum with a serrated rim; the spur of Myzinum is equipped with a velum with a smooth rim; in Thynnus the surface of the velum is wrinkled or undulating. An apex (without teeth) is present in all investigated Tiphiidae. The notch of the basitarsus bears a comb except in female Myzinum, where the teeth seem to have fused, thus forming a rim. It is suggested that a velum with a serrated or toothed edge and an apex with two rows of teeth are plesiomorphic for aculeate Hymenoptera. The antenna cleaners in Mutillidae are remarkably similar to those in some bees. This fact is interpreted as partly due to convergence and as partly symplesiomorphic. In several species of ants, there is a specialized cuticular area (bande poreuse) anterior to the comb of the notch, which is characterized by fissures or holes. These are presumably openings of an excretory gland.     

The regulation of urease activity in Aspergillus nidulans

Aspergillus nidulans can utilize urea as a sole source of nitrogen but not as a carbon source. Urea is degraded by a urease. Mutation at any one of three genes, ureB, ureC, and ureD, may result in deficient urease activity. The ureB gene is closely linked to ureA, the structural gene for the urea transport protein. The heat lability of a ureB ^– revertant strain, intragenic complementation tests, and the linkage of ureB to ureA suggest that ureB is the urease structural gene. The ureD gene is probably involved in the synthesis or incorporation of a nickel cofactor essential for urease activity. The function of the ureC gene is not known. Urease is not induced but is subject to nitrogen regulation. The urease activities of ammonium-derepressed mutants show that the effector of nitrogen regulation is more likely to be glutamine than ammonium. When glutamine is present in the medium, urease appears to be inactivated by some means which does not involve a newly synthesized protease or a direct interaction between glutamine and urease.