Introduction a l'Histoire naturelle et a la Géographie physique de l'Espagne

Sign.: a6, A-Z8, 2A-2I8, 2K2

Concerted involvement of Cdx/Hox genes and Wnt signaling in morphogenesis of the caudal neural tube and cloacal derivatives from the posterior growth zone

Decrease in Cdx dosage in an allelic series of mouse Cdx mutants leads to progressively more severe posterior vertebral defects. These defects are corrected by posterior gain of function of the Wnt effector Lef1. Precocious expression of Hox paralogous 13 genes also induces vertebral axis truncation by antagonizing Cdx function. We report here that the phenotypic similarity also applies to patterning of the caudal neural tube and uro-rectal tracts in Cdx and Wnt3a mutants, and in embryos precociously expressing Hox13 genes. Cdx2 inactivation after placentation leads to posterior defects, including incomplete uro-rectal septation. Compound mutants carrying one active Cdx2 allele in the Cdx4-null background (Cdx2/4), transgenic embryos precociously expressing Hox13 genes and a novel Wnt3a hypomorph mutant all manifest a comparable phenotype with similar uro-rectal defects. Phenotype and transcriptome analysis in early Cdx mutants, genetic rescue experiments and gene expression studies lead us to propose that Cdx transcription factors act via Wnt signaling during the laying down of uro-rectal mesoderm, and that they are operative in an early phase of these events, at the site of tissue progenitors in the posterior growth zone of the embryo. Cdx and Wnt mutations and premature Hox13 expression also cause similar neural dysmorphology, including ectopic neural structures that sometimes lead to neural tube splitting at caudal axial levels. These findings involve the Cdx genes, canonical Wnt signaling and the temporal control of posterior Hox gene expression in posterior morphogenesis in the different embryonic germ layers. They shed a new light on the etiology of the caudal dysplasia or caudal regression range of human congenital defects.

Escalafón de antigüedad de los catedráticos numerarios de las universidades del Reino en ... /

Algunos años publicada por: Imprenta del Colegio Nacional de Sordomudos y de Ciegos.

Tractatus de iure et priuilegiis honestatis : in duodeuiginti articulos distributus, quibus vniuersim honesti ius, ac quod ad singulos personarum status pertinet, explicatur ... /

Mode of access: Internet.

Tratado de patología externa y medicina operatoria /

Mode of access: Internet.

Earnings behaviour of financially distressed firms:The role of institutional ownership

Using a sample of 859 U.S. bankruptcy-filing firms over the period 1986-2004, we examine the earnings behaviour of managers during the distressed period by looking at sources of abnormal accruals prior to the bankruptcy-filing year. Results show that managers of highly distressed firms shift earnings downwards prior to the bankruptcy filing. We test and provide evidence in support of two potential contributing factors. First, top-level management turnover among distressed firms leads new managers to earnings bath choices during the distressed period. Second, qualified audit opinions exert pressure on managers to follow more conservative earnings behaviour during the distressed period. Evidence is also provided that the management of distressed firms with lower (higher) institutional ownership has greater (lesser) tendency to manage earnings downwards. Results also show that higher institutional ownership mitigates the negative abnormal returns of firms with top management turnover. To the authors' knowledge, this is the first study that attempts to examine whether institutional ownership relates to market reaction in conjunction with a top management turnover or a qualified audit opinion during the distressed period. Prior studies focused on the investigation of earnings management or institutional ownership (separately) during the distressed period, but did not examine if the effect of institutional ownership on earnings behaviour also influences subsequent returns. Thus, the results of this study should be of interest to analysts, standard setters and regulatory bodies since our results show that management turnover, qualified audit opinions and firm governance mechanisms affect the quality of earnings and the level of abnormal returns. © 2007 Accounting Foundation, The University of Sydney.

Local luminance amplitude modulates the interpretation of shape-from-shading in textured surfaces

The pattern of illumination on an undulating surface can be used to infer its 3-D form (shape-from-shading). But the recovery of shape would be invalid if the luminance changes actually arose from changes in reflectance. So how does vision distinguish variation in illumination from variation in reflectance to avoid illusory depth? When a corrugated surface is painted with an albedo texture, the variation in local mean luminance (LM) due to shading is accompanied by a similar modulation in local luminance amplitude (AM). This is not so for reflectance variation, nor for roughly textured surfaces. We used depth mapping and paired comparison methods to show that modulations of local luminance amplitude play a role in the interpretation of shape-from-shading. The shape-from-shading percept was enhanced when LM and AM co-varied (in-phase) and was disrupted when they were out of phase or (to a lesser degree) when AM was absent. The perceptual differences between cue types (in-phase vs out-of-phase) were enhanced when the two cues were present at different orientations within a single image. Our results suggest that when LM and AM co-vary (in-phase) this indicates that the source of variation is illumination (caused by undulations of the surface), rather than surface reflectance. Hence, the congruence of LM and AM is a cue that supports a shape-from-shading interpretation. © 2006 Elsevier Ltd. All rights reserved.

Seasonal variations in surface metabolite composition of Fucus vesiculosus and Fucus serratus sampled at outer Kiel Fjord (August 2012 - July 2013)

The chemical composition of surface associated metabolites of two Fucus species (Fucus vesiculosus and Fucus serratus) was analysed by means of gas chromatography-mass spectrometry (GC-MS) to describe temporal patterns in chemical surface composition. Method: The two perennial brown macroalgae F. vesiculosus and F. serratus were sampled monthly at Bülk, outer Kiel Fjord, Germany (54°27'21 N / 10°11'57 E) over an entire year (August 2012 - July 2013). Per month and species six non-fertile Fucus individuals were collected from mixed stands at a depth of 0.5 m under mid water level. For surface extraction approx. 50 g of the upper 5-10 cm apical thalli tips were cut off per species. The surface extraction of Fucus was performed according to the protocol of de Nys and co-workers (1998) with minor modifications (see Rickert et al. 2015). GC/EI-MS measurements were performed with a Waters GCT premier (Waters, Manchester, UK) coupled to an Agilent 6890N GC equipped with a DB-5 ms 30 m column (0.25 mm internal diameter, 0.25 mM film thickness, Agilent, USA). The inlet temperature was maintained at 250°C and samples were injected in split 10 mode. He carrier gas flow was adjusted to 1 ml min-1. Alkanes were used for referencing of retention times. For further details (GC-MS sample preparation and analysis) see the related publication (Rickert et al. submitted to PLOS ONE).

Costa Rica en el marco del TLC CA-EE.UU. y sus consecuencias en el área de telecomunicaciones

Introducción Costa Rica ocupa, en América Latina, el primer lugar en cuanto a desarrollo en el campo de telecomunicaciones, con una densidad de 28.54 líneas por cada 100 habitantes, Ocupamos, además, el primer lugar en América Latina en completición de llamadas desde EE.UU., el indicador que más integrante podría reflejar la calidad de la red telefónica de un país, con un 71.47%. En relación con la productividad, Costa Rica exhibe una de las más altas del mundo, 5.35 empleados por cada 1000 líneas telefónicas. El promedio para el Continente Americano es de 5.49, para Europa 6.10 y para África 12.82.