ENTREPRENEURIAL AND MARKET-ORIENTED ACTIVITIES, FINANCIAL CAPITAL, ENVIRONMENT TURBULENCE, AND EXPORT PERFORMANCE IN AN EMERGING ECONOMY

This study examines the impact of the simultaneous implementation of entrepreneurial and market-oriented export activities on export success and whether this relationship depends on levels of financial capital and market environment turbulence. The findings from a study of 164 Ghanaian exporting small and medium-sized enterprises (SMEs) indicate that high levels of both entrepreneurial and market orientation generate better export performance. The relationship is stronger when firms have greater financial capital and operate in more turbulent export market environments. These results extend existing knowledge of how SMEs can improve export performance by seeking fit between firm-specific capabilities and external environment conditions

Evaluation of foliar resistance to downy mildew in different cv. Albariño clones

Resistance to downy mildew was studied in different Vitis vinifera L. cv. Albariño clones belonging to the collection of the Mision Biológica de Galicia, CSIC (Spain). V. riparia, V. vinifera cv. Solaris and V. vinifera cv. Müller-Thurgau were used as controls. Plants were inoculated with Plasmospora viticola in the laboratory using the leaf disc, whole leaf and whole plant techniques. The results were compared with those obtained in the field for the same Albariño clones. The most susceptible group of clones included MBG-2, MBG-14, MBG-12 and MBG-9, while MBG-13, MBG-3 and MBG-6 formed the most resistant group. The remaining clones showed intermediate resistance. These results coincide with observations made in the field. The resistance observed in MBG-12 could have been generated from in vitro culture, because this induces changes in the downy mildew resistance.

Macro- and microscopic leaf characteristics of six grapevine genotypes (Vitis spp.) with different susceptibilities to grapevine downy mildew

This work reports the leaf morphology of six grapevine genotypes, five belonging to Vitis vinifera and one to Vitis riparia. Earlier studies on these genotypes showed different levels of susceptibility to grapevine downy mildew (Plasmopara viticola). The aim of this work was to detect differences between the leaf morphology of these cultivars at the macro- and microscopic levels, and to characterize morphological traits which could be associated with susceptibility and resistance to downy mildew. An ampelographic description of each genotype was used to develop a scheme illustrating the characteristic leaf morphology. The density and morphology of the trichomes and the stomatal index was assessed by means of microscopical techniques. Distinct macro and microscope differences among the genotypes were seen. No clear relation between ampelographic characteristics and susceptibility to downy mildew was observed. The two cultivars that in earlier studies were found to be the least susceptible to downy mildew were the most similar in terms of their spongy mesophyll. Both showed very little or no wax on the abaxial surface of their leaves.

Characterisation and identification of grapevine cultivars (Vitis vinifera L.) from northwestern Spain using microsatellite markers and ampelometric methods

Nine grapevine varieties from northwestern Spain (8 commonly known as types of Caíño and one as Tinta Femia) were characterised by constructing their typical ‘mean leaves’ and by determining their genetic profiles with respect to 6 microsatellite markers. Leaf morphologies were compared and the similarities between the cultivars were determined. Thirty three alleles were detected at the 6 microsatellite loci analysed. The different cultivars were successfully identified by both methods. In combination, the different techniques provide a more complete variety characterisation. Synonymy between these and other Spanish and Portuguese cultivars is discussed.

Variability of the stomata among 'Albariño' (Vitis vinifera L.) clones and its relationship with susceptibility to downy mildew

Research Note

A parametric study of a multiphase porous media model for tumor spheroids and environment interactions

Computational models for tumor growth provide an effective in silico tool to investigate the different stages of cancer growth. Recently, a series of computational models based on porous media theory has been proposed to predict tumor evolution and its interactions with the host tissue. In addition, a specialization of the original models, adapted for tumor spheroids, has been proposed and validated experimentally. However, due to the complexity of the modeling framework, a systematic understanding of the role of the parameters governing the equations is still lacking. In this work, we perform a parametric analysis on a set of fundamental parameters appearing in the model equations. We investigate the effects of a variation of these coefficients on the spheroid growth curves and, in particular, on the final radii reached by the cell aggregates in the growth saturation stage. Finally, we provide a discussion of the results and give a brief summary of our findings

Memory effect in silicon time-gated single-photon avalanche diodes

We present a comprehensive characterization of the memory effect arising in thin-junction silicon Single-Photon Avalanche Diodes (SPADs) when exposed to strong illumination. This partially unknown afterpulsing-like noise represents the main limiting factor when time-gated acquisitions are exploited to increase the measurement dynamic range of very fast (picosecond scale) and faint (single-photon) optical signals following a strong stray one. We report the dependences of this unwelcome signal-related noise on photon wavelength, detector temperature, and biasing conditions. Our results suggest that this so-called "memory effect" is generated in the deep regions of the detector, well below the depleted region, and its contribution on detector response is visible only when time-gated SPADs are exploited to reject a strong burst of photons