The Neuropteris ovata frond and its cyclopteroids: Micromorphology-spectrochemistry-fractal taxonomy. Propositions for restructuring and taxonomy (Pennsylvanian, Canada)

The primary study material consists of the 65-cm frond Neuropteris ovata (Hoffmann) var. simonii, associate petiole with organically attached cyclopteroid leaflets and trunk. Ancillary N. ovata material is used, all from the Asturian-Cantabrian strata of the Sydney Coalfield, Canada. This material is appropriate for the objective of the study to present an ovata-frond Aufbau in terms of micromorphology coupled with chemistry using an holistic sampling design (co-ordinating epidermal microscopy with chemistry per sample location). Chemical analyses were obtained by the reliable FTIR technique (Fourier transform infrared spectroscopy) and interpreted via chemometrics by methods of principal component analysis. Fractal geometry is introduced as a promising taxonomic parameter. The main conclusions include that the N. ovata plant can be characterized by three distinct epidermal structures: (1) rectangular elongate (trunk and petiole), (2) elongate (rachides of three orders), and (3) undulate (pinnule), which to a certain extent agrees with the chemistry of the frond Aufbau. The frond was also complex - architecturally, histologically, physiologically, chemically and autecologically. It was photosynthetic, had secretory organs (implying a characteristic plant aroma), supporting rodlets, divers epicuticular features, and a distinct chemical composition/structure. The frond was likely 4 m long with complex-pinnate cyclopteroid leaflets, fimbriate or entire-margined, below and above the main bifurcation, which begs the question of cyclopteroid definition and function. The overall results will be beneficial to taxonomy/systematics, and guide pteridospermous reconstruction into a new paradigm.Fil: Zodrow, E. L.. Cape Breton University; CanadáFil: D`angelo, José Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Cleal, C.. National Museum Wales; Reino Unid

Minimum taxes and repeated tax competition

An agreement about a lower bound for admissible tax rates can reduce the equilibrium tax rate (and thus welfare) in tax competition among fully symmetric countries. This is shown in an infinitely repeated game where the stage game describes the standard tax competition model with source-based taxes and symmetric countries. Repeated interaction may allow countries to sustain cooperation through implicit contracts. Lower bounds on tax rates ('minimum taxes') restrict the ability of countries to punish deviators. This makes cooperation harder to sustain. The introduction of a lower bound on feasible tax rates may thus harm all countries

Cigarette smoke induces genetic instability in airway epithelial cells by suppressing FANCD2 expression

Chromosomal abnormalities are commonly found in bronchogenic carcinoma cells, but the molecular causes of chromosomal instability (CIN) and their relationship to cigarette smoke has not been defined. Because the Fanconi anaemia (FA)/BRCA pathway is essential for maintenance of chromosomal stability, we tested the hypothesis that cigarette smoke suppresses that activity of this pathway. Here, we show that cigarette smoke condensate (CSC) inhibited translation of FANCD2 mRNA (but not FANCC or FANCG) in normal airway epithelial cells and that this suppression of FANCD2 expression was sufficient to induce both genetic instability and programmed cell death in the exposed cell population. Cigarette smoke condensate also suppressed FANCD2 function and induced CIN in bronchogenic carcinoma cells, but these cells were resistant to CSC-induced apoptosis relative to normal airway epithelial cells. We, therefore, suggest that CSC exerts pressure on airway epithelial cells that results in selection and emergence of genetically unstable somatic mutant clones that may have lost the capacity to effectively execute an apoptotic programme. Carcinogen-mediated suppression of FANCD2 gene expression provides a plausible molecular mechanism for CIN in bronchogenic carcinogenesis

Fiscal Federalism and Foreign Transfers: Does Inter-Jurisdictional Competition Increase Foreign Aid Effectiveness?

This paper empirically studies the impact of decentralization and inter-jurisdictional competition on foreign aid effectiveness. For this purpose we examine a commonly used empirical growth model, considering different measures of fiscal decentralization. Our panel estimations reveal that expenditure decentralization and inter-jurisdictional competition - reflected by the degree of tax revenue decentralization - negatively impact aid effectiveness. We therefore conclude that donor countries should carefully consider how both anti-poverty instruments - foreign assistance and decentralization - work together