Visceral vasculature in the family Cordylidae (Reptilia: Squamata)

Major circulatory patterns in lizards of the family Cordylidae are poorly known, but may serve as a source of characters for systematics. Two specimens each of the cordylines, Cordylus jordani and C. pofyzonus, and the gerrhosaurine, Zonosaurus madagascariensis were prepared by Microfil™ injection and whole body clearing and staining to serve as the basis for a comparison of cordylid visceral vasculature. The greatest amount of variation within the family is seen in the vessels of the hepatic portal system, whereas venous drainage and the arterial system (exclusive of the coeliac artery and its branches) are largely conservative within the group. Despite extensive homoplasy in lizards as a whole, cordylids (sensu lato), and especially gerrhosaurines, share a number of features of vasculature that support their sister-group relationship to the Scincidae. The proximity of the origin of the anterior and posterior mesenteric arteries stands as a putative synapomorphy of cordylines + gerrhosaurines. Features of the hepatic portal drainage may be autapomorphic for the genus Cordylus or for cordylines as a whole

Utilization of the termite Hodotermes mossambicus (Hagen) by gekkonid lizards near Keetmanshoop, South West Africa

Five species of primarily nocturnal geckos (Ptenopus garrulus maculatus, Chondrodactylus angulifer angulifer, Pachydactylus bibronii, P. mariquensis latirosths and P. punctatus) collected near Keetmanshoop, South West Africa on the night of 3 October 1987 were found to contain large numbers of the harvester termite Hodotermes mossambicus. The mass of termites consumed ranged up to 61,1% of empty gecko body weight. Termite consumption of this magnitude and extensive above-ground foraging by large numbers of Ptenopus appear to be uncommon and probably reflect gecko usage of a large-scale Hodotermes foraging bout associated with the onset of the rainy season. The availability of such a concentrated food resource may be particularly important for vitellogenic female geckos

Skin mechanics and morphology of two species of Pachydactylus (Reptilia:Gekkonidae)

The southern African species Pachydactylus namaquensis is one of only a few mainland species of geckos that exhibits the escape strategy of regional integumentary loss. The skin morphology and mechanics of this species were compared to the same parameters in lhe sympatric congener P. bibronii. The tensile strength and modulus of elasticity of the skin of both species fall in the middle range of values for geckos as a whole. Skin of P. namaquensis,however, has approximately half of the tensile strength of that of P. bibronii. As in other skin-losing forms, the morphological basis for weakness lies in the bilayering of the dermis and the presence of zones of weakness within the upper layer of the dermis. Field experience suggests that P. namaquensis does not lose the skin as easily as most geckos exhibiting regional integumentary loss. In this species this escape strategy has probably evolved in response to the prey subjugation mode employed by rock-dwelling lizard predators

Acrolein Dimer as a Marker for Direct Detection of Acrolein in Wine

Acrolein is highly toxic and its presence in wine has been correlated with the development of bitterness.Analytical detection and quantification in aqueous solutions are challenging due to high reactivityand problems with chemical derivative analysis. Here we demonstrate the potential of a naturalderivative, formed under conditions prevailing in wine, as a marker for acrolein detection. Solid-phasemicroextraction (SPME) coupled with gas chromatograph mass spectrometry (GC-MS) was validated asa technique for direct detection of the acrolein dimer. Conventional GC-MS analysis using a quadrupolemass spectrometer did not provide sufficient chromatographic resolution for the separation of the targetanalyte from interfering compounds. Accurate mass measurements with time-of-flight (TOF)-MS, on theother hand, allowed qualitative and quantitative measurements of the acrolein dimer. This work lays theanalytical foundation for studies on the evolution of acrolein and its dimer in solution

Two new species of diminutive leaf-litter skinks (Squamata: Scincidae: Tytthoscincus) from Gunung Penrissen, Sarawak, Malaysia (northern Borneo)

We describe two new species of skinks from Gunung Penrissen, Sarawak, Malaysia, in northern Borneo, Tytthoscincus batupanggah sp. nov. and T. leproauricularis sp. nov. Morphological and molecular analyses both corroborate the two new species as unique compared to all other Tytthoscincus and additional Sphenomorphus that are candidates for taxonomic placement in the genus Tytthoscincus. Despite their phenotypic similarity and sympatric distribution, a molecular analysis shows that the new species are not sister taxa and exhibit a deep genetic divergence between each of their respective sister taxa. We discuss how historical climatic and geographic processes may have led to the co-distribution of two relatively distantly related phenotypically similar species. In light of these discoveries, we also emphasize the importance of conserving primary montane tropical rainforest for maintaining species diversity

La relación personal en el tratamiento de la diversidad

El autor centra su aportación en diferentes características de los organismos vivos, para incorporarlas a las perspectivas interpretativas y operativas, y de los métodos actuales de intervención educativa. En el texto también se trata el enfoque positivo desde la dimensión técnica y no «voluntarista», teniendo en cuenta que los especialistas que adoptan la perspectiva del enfoque positivo dan mucha importancia al tema de la calidad de vida.L'autor centra la seva aportació en diferents característiques dels organismes vius, per incorporar- les a les perspectives interpretatives i operatives, i dels mètodes actuals d'intervenció educativa. Al text també es tracta l'enfocament positiu des de la seva dimensió tècnica i no «voluntarista», tenint en compte que els especialistes que adopten la perspectiva de l'enfocament positiu donen molta importància al tema de la qualitat de vida.The author focuses on the different characteristics of the alive organisms in order to include them into the interpretative and operative views of the current methods of educational intervention. He also deals with the positive focus, from the technical and «no voluntary» dimension, taking into account that those specialists having this kind of view do emphasize a lot on the quality of life issue

Solving Virasoro Constraints on Integrable Hierarchies via the Kontsevich-Miwa Transform

We solve Virasoro constraints on the KP hierarchy in terms of minimal conformal models. The constraints we start with are implemented by the Virasoro generators depending on a background charge $Q$. Then the solutions to the constraints are given by the theory which has the same field content as the David-Distler-Kawai theory: it consists of a minimal matter scalar with background charge $Q$, dressed with an extra `Liouville' scalar. The construction is based on a generalization of the Kontsevich parametrization of the KP times achieved by introducing into it Miwa parameters which depend on the value of $Q$. Under the thus defined Kontsevich-Miwa transformation, the Virasoro constraints are proven to be equivalent to a master equation depending on the parameter $Q$. The master equation is further identified with a null-vector decoupling equation. We conjecture that $W^{(n)}$ constraints on the KP hierarchy are similarly related to a level-$n$ decoupling equation. We also consider the master equation for the $N$-reduced KP hierarchies. Several comments are made on a possible relation of the generalized master equation to {\it scaled} Kontsevich-type matrix integrals and on the form the equation takes in higher genera.Comment: 23pp (REVISED VERSION, 10 April 1992

Photoproduction of mesons in nuclei at GeV energies

In a transport model that combines initial state interactions of the photon with final state interactions of the produced particles we present a calculation of inclusive photoproduction of mesons in nuclei in the energy range from 1 to 7 GeV. We give predictions for the photoproduction cross sections of pions, etas, kaons, antikaons, and $\pi^+\pi^-$ invariant mass spectra in ^{12}C and ^{208}Pb. The effects of nuclear shadowing and final state interaction of the produced particles are discussed in detail.Comment: Text added in summary in general reliability of the method, references updated. Phys. Rev. C (2000) in pres

On centralizer algebras for spin representations

We give a presentation of the centralizer algebras for tensor products of spinor representations of quantum groups via generators and relations. In the even-dimensional case, this can be described in terms of non-standard q-deformations of orthogonal Lie algebras; in the odd-dimensional case only a certain subalgebra will appear. In the classical case q = 1 the relations boil down to Lie algebra relations