The cholesterol concentration at the cell surface of cultured chick myocytes was increased in order to determine the effects of high levels of cholesterol on the ion channel properties of the nicotinic acetylcholine receptor. Single channel recordings and fluorescence polarization studies using 1,6-diphenyl-1,3,5-hexatriene (DPH) were performed under equivalent conditions for normal and cholesterol enriched myocytes. In cell attached patches from myocytes with a cholesterol to phospholipid molar ratio (c/p) of 0.24 and a microviscosity of 1.35 poise a single conductance of 51 pS was detected. The cholesterol enriched myocytes with a c/p of 0.52 and a microviscosity of 2.05 poise showed two conductances, a 54 pS and a 39 pS channel: both were blocked by alpha-bungarotoxin. The 39 pS channel was detected with the simultaneous appearance of a slow component of tau m (modulation time) for DPH fluorescence measured by phase demodulation. The 80% reduction in the open time constant (tau 2) of the 39 pS channel suggest an inhibition of the normal conformational state. The combined results suggest that cholesterol enrichment may induced a more heterogeneous lipid environment and that the two types of channel properties could result from the distribution of the receptors in different domains.

This study examines company-specific factors that may help explain the choice of an exportmarket strategy and explores how the selected export strategy contributes to explaining company's export performance (XP). Concentrating on a specific area within a broad spectrum of export behavior analysis has enabled us to examine these factors in greater depth. The results of our research, which was carried out using a sample comprising Spanish exporting companies, show a firm's size, a firm's age, and a firm's greater foreign ownership in its share capital are all determining factors for adopting a strategy geared to export-market diversification. A greater level of investment in R&D and greater international commitment are also important in this regard. We suggest reinforcing these two factors because there is evidence of a better XP among firms that have a wider range of foreign markets.

SUMMARYTo know in the logistics of pig transports in Spain 566 journeys, concerning 34 slaughterhouses and 13 traders, were surveyed by means of questionnaires collecting information relative to 119 transport aspects. Trucks loaded pigs in 1,5 farms on average, loading an average of 160 slaughter pigs or 493 piglets transported to growing farms, with an average stocking density of 214.4 and 103.8 kg/m 2 respectively. Pigs were fasted previous to the journey an average of 14.5 hours in 79.2% of slaughter journeys, which lasted 3.4 hours on average, less than half the average duration of farm transports (7.3 hours, p<0.001). In 39% of piglet transports the duration was higher than 8 hours, and in no case a 24 hour stop was necessary, although the percentage of journeys with more than 2 stops was higher than in slaughter transports (22.6% vs. 4.1%; p<0.001). More than 95% of journeys were carried out with one driver, who participated in the loading and unloading of the animals in more than 97% of the cases, and was assisted by another person in 79% of the unloadings at the slaughterhouse (p<0.01). The average loading time was similar between farm and slaugher transports (102 minutes), although the individual loading time in slaughter transports was higher (1.2 minutes/ animal). The unloading was faster at slaughterhouses than in farms (52.9 vs. 25.0 minutes; p<0.001), although the individual loading time was similar for both destinations (0.31 minutes). In both destinations the number of journeys with at least one dead animal was similar (12%), although the average number of dead animals/journey was higher in transports to farm (1.6 animals/journey; p<0.05). No injured pigs were detected at the end of the farm transports, although lesions were found at the end of 17.8% of slaughter transports (3.6 injured pigs/journey on average). Farm and slaughter transports were mainly carried out with vehicles owned by traders or specialized transportists (61.0% y 74.1% respectively; p<0.001), with an average drivers' experience about 15 years. More than 15% of drivers declared to know the current animal welfare legislation, above 48% declared to believe that legislation is not totally complied with, and that legislation should approach more to real transport circumstances. More information and a better scientific basis of the aspect of stops during the journey were demanded. Due to their way of acting is mainly based in a consolidated experience, additional descriptive studies of the activity of livestock transportists are important. RESUMEN Para conocer la logística de cerdos en EspañaArchivos de zootecnia vol. 60, núm. 230, p. 184. GOSÁLVEZ, RIU, HERRANZ, COLOM AND AVERÓSse estudiaron 566 viajes, relativos a 34 mataderos y 13 comerciantes, mediante cuestionarios que recogían información relativa a 119 aspectos del transporte. La carga se efectuó en una media de 1,5 granjas, transportando una media de 160 cerdos a sacrificio o 493 lechones destinados a granja de cebo, suponiendo una densidad media de 214,4 y 103,8 kg/m 2 resp...

To know in the logistics of pig transports in Spain 566 journeys, concerning 34 slaughterhouses and 13 traders, were surveyed by means of questionnaires collecting information relative to 119 transport aspects. Trucks loaded pigs in 1,5 farms on average, loading an average of 160 slaughter pigs or 493 piglets transported to growing farms, with an average stocking density of 214.4 and 103.8 kg/m 2 respectively. Pigs were fasted previous to the journey an average of 14.5 hours in 79.2% of slaughter journeys, which lasted 3.4 hours on average, less than half the average duration of farm transports (7.3 hours, p<0.001). In 39% of piglet transports the duration was higher than 8 hours, and in no case a 24 hour stop was necessary, although the percentage of journeys with more than 2 stops was higher than in slaughter transports (22.6% vs. 4.1%; p<0.001). More than 95% of journeys were carried out with one driver, who participated in the loading and unloading of the animals in more than 97% of the cases, and was assisted by another person in 79% of the unloadings at the slaughterhouse (p<0.01). The average loading time was similar between farm and slaugher transports (102 minutes), although the individual loading time in slaughter transports was higher (1.2 minutes/ animal). The unloading was faster at slaughterhouses than in farms (52.9 vs. 25.0 minutes; p<0.001), although the individual loading time was similar for both destinations (0.31 minutes). In both destinations the number of journeys with at least one dead animal was similar (12%), although the average number of dead animals/journey was higher in transports to farm (1.6 animals/journey; p<0.05). No injured pigs were detected at the end of the farm transports, although lesions were found at the end of 17.8% of slaughter transports (3.6 injured pigs/journey on average). Farm and slaughter transports were mainly carried out with vehicles owned by traders or specialized transportists (61.0% y 74.1% respectively; p<0.001), with an average drivers' experience about 15 years. More than 15% of drivers declared to know the current animal welfare legislation, above 48% declared to believe that legislation is not totally complied with, and that legislation should approach more to real transport circumstances. More information and a better scientific basis of the aspect of stops during the journey were demanded. Due to their way of acting is mainly based in a consolidated experience, additional descriptive studies of the activity of livestock transportists are important. RESUMEN Para conocer la logística de cerdos en EspañaArchivos de zootecnia vol. 60, núm. 230, p. 184. GOSÁLVEZ, RIU, HERRANZ, COLOM AND AVERÓS se estudiaron 566 viajes, relativos a 34 mataderos y 13 comerciantes, mediante cuestionarios que recogían información relativa a 119 aspectos del transporte. La carga se efectuó en una media de 1,5 granjas, transportando una media de 160 cerdos a sacrificio o 493 lechones destinados a granja de cebo, suponiendo una densidad media de 214,4 y 103,8 kg/m 2 respecti...