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This paper describes the development and use of a thermofluidynamic model for parabolic trough collectors, specifically suited for carrying out systematic calculations on different design options. The model is based on detailed energy balances, and it has been applied to evaluate collector thermal performances with different working fluids: oil, molten salt, or water/steam. For each heat transfer fluid technology, four parameters have been analyzed: collector length, absorber tube diameter, working temperature, and pressure. The influence of these factors has been studied from the point of view of heat loss, pressure drop, energy, and exergy efficiencies. Exergy is considered the suitable magnitude to guide any optimization process in this field, because it accounts for all relevant energy gains and losses, characterized by their corresponding temperature and pressure. Preliminary conclusions point out that direct steam generation is more efficient than oil and molten salt systems. [DOI: 10.1115/1.4001399] Keywords: parabolic trough, thermofluidynamic model, molten salt, oil, water/steam, exergy

The beach of Porto de Galinhas is socially and economically important because of the reef environment that attracts a large number of tourists. In order to contribute to the monitoring of the environmental quality of the area, which is subject to strong human pressure, phytoplankton composition was analysed in four fixed sampling station, during 4 months of the dry and rainy periods, at high and low tides and at diurnal spring tides. The phytoplankton community structure and the abiotic parameters varied according to seasonality. Phytoplankton biomass ranged from 0.42 to 5.66 mg m−3 and density ranged from 0.50 to 14.3 cell 103 l−1. A total of 192 taxa were identified, belonging to six divisions. The most representative taxa were Ochrophyta (64.6%), followed by Dinophyta (19.3%). Ostreopsis ovata, Trichodesmium erythraeum, Protoperidinium bispinum, Paralia sulcata, Thalassiosira leptopus and Fragilaria capucina were the most representative species of the environment. Ostreopsis ovata was the only highly frequent and dominant species. The Easterly Wave Disturbance contributed to the occurrence of a large number of freshwater species that were observed on the site. The environment was characterized as oligotrophic, tending toward mesotrophic in the rainy season. The high number of taxa associated with high evenness was indicative of environmental balance. Continental interference was perceived due to the variation of abiotic parameters and of the variation of the phytoplankton community structure. [ABSTRACT FROM AUTHOR]

A new Hessian fly (Mayetiola destructor Say) resistance gene from Aegilops triuncialis and its transfer to hexaploid wheat via interspecific hybridisation is described. The transfer line TR-3531 (42 chromosomes), derived from the cross [(Triticum turgidum × Ae. triuncialis) × Triticum aestivum] and carrying the Heterodera avenae resistance gene Cre7, showed a high level of resistance to the M. destructor biotype prevailing in the SW of Spain. A single dominant gene (H30) seems to determine the Hessian fly resistance in this introgression line, and its linkage with an isozyme marker (Acph-U1) has also been studied. It has been demonstrated that the resistance gene H30 in the TR-3531 line is non-allelic with respect to the genes H3, H6, H9, H11, H12, H13, H18 and H21, present in wheat cultivars from the Uniform Hessian Fly Nursery (UHFN), as well as to H27, carried by the introgression line H-93-33. Advanced lines with the H30 gene were obtained by backcrossing the transfer line and different commercial wheats as recurrent parents. Several of them showed a high yield in tests carried out in the infested field. Electronic Supplementary Material is available if you access this article at http://dx.doi.org/10.1007/s00122-002-1182-z. On that page (frame on the left side), a link takes you directly to the supplementary material. [ABSTRACT FROM AUTHOR]

Studies genetic relationships and isozyme variability in the Heterodera avenae complex determined by isoelectrofocusing. Genetic variation among populations of Heterodera avenae; Usefulness of isozyme fractionation by isoelectrofocusing; Polymorphisms detected in isoenzymatic systems.

Previous reports in human and mouse material demonstrated that decidual stromal cells expressed antigens associated with haematopoietic cells, exerted immune functions, and originated from bone marrow. These findings suggested that these cells belonged to the haematopoietic lineage. We purified and expanded in culture precursors of human decidual stromal cells, and found in electron microscopic images that the ultrastructure of these cells was similar to that of myofibroblasts, which are of mesenchymal origin. The relationship between these two types of cell was confirmed by the detection (by flow cytometry) in the decidual precursors of α-smooth muscle actin, a contractile microfilament expressed solely by smooth muscle cells, myofibroblasts and related cells. This filament was also detected in decidual stromal cells decidualized in vitro by the effect of progesterone. We also found vimentin in decidual precursors and decidualized cells. This intermediate filament has been previously reported to be expressed by all decidual stromal cells and also by myofibroblasts. Desmin, another intermediate filament expressed by myofibroblasts, was not detected in the decidual precursors; however, this filament was observed in decidualized cells. The expression of α-smooth muscle actin by decidual stromal cells was also found by immunostaining in cryostat sections of early decidua. Our results suggest that decidual stromal cells are related to myofibroblasts. [ABSTRACT FROM PUBLISHER]