Time for change in Portuguese science

There is an almost perfect positive relationship between scientific output and gross domestic product (GDP) in Western Europe (Fig. 1). But two countries — Ireland and Portugal — spoil the relationship

Canarias libre y socialista

VILADOT-CEDO

Hormonal control of swimbladder sonic muscle dimorphism in the Lusitanian toadfish, Halobatrachus didactylus

The swimbladder and associated sonic muscle of the Lusitanian toadfish Halobatrachus didactylus increase in size throughout life and are, respectively, 25% and 30% larger in type I (nest-holder) males than females, which may generate sexual differences in sound production. Sexual dimorphism in swimbladder is also evident in the morphological features of sonic muscle fibers. During the breeding season, type I males have smaller myofibril contracting zones surrounded by larger sarcoplasm areas compared with females, possibly an adaptation to speed and fatigue resistance for the production of long mating calls. Type II (floater) males show characteristics that are intermediate, but statistically not significantly different, between type I males and females. Six weeks after castration and androgen (testosterone and 11- ketotestosterone) replacement in type I and type II males there were no alterations either in swimbladder mass or fiber morphology. However, 17b-estradiol induced a significant decrease in swimbladder mass and sarcoplasm area/myofibril area ratio. Six months after castration there was a clear reduction in the seasonal swimbladder hypertrophy in males and induction of sonic fiber morphological characteristics that resemble those occurring in females (low sarcoplasm area/myofibril area ratio). These results suggest that testicular factors are required to initiate sonic muscle hypertrophy and type I sonic fiber phenotype in H. didactylus, but a specific involvement of androgens has not been completely clarified

Morphometric changes and sex steroid levels during the annual reproductive cycle of the Lusitanian toadfish, Halobatrachus didactylus

The Lusitanian toadfish has group synchronous oocytes, which grow from November until June–July when they are released probably as a single batch. Blood plasma levels of estradiol-17b (E2) and testosterone (T) increase during vitellogenesis and drop rapidly during final maturation and ovulation, when 17,20b, 21-trihydroxy-4-pregnen-3-one (17,20b,21-P) levels increase. The male reproductive apparatus is composed of paired testes and multichambered accessory glands, which secrete mucosubstances and are connected to the spermatic duct. Changes in the gonadosomatic index of males paralleled the females but started to drop slightly earlier. The swimbladder and accessory glands also underwent important seasonal changes in weight reaching a maximum at spawning. T, 11-ketotestosterone (11-KT) and 17,20a-dihydroxy-4-pregnen-3-one (17,20a-P) were generally low except for a sharp peak in June. 17,20b,21-P also peaked in June and then declined slowly. 17,20b-dihydroxy-4-pregnen-3-one (17,20a-P) was undetectable in males and females. As with other species of the family two types of males were identified: type I males with smaller testes (ca. 7-fold) and larger accessory glands (ca. 3-fold) and swimbladders than type II. Type I males also had significantly higher (ca. 6- fold) 11-KT levels than type II males. This suggests a role for 11-KT in the development of structures important for reproductive behaviour

The swimbladder of the Lusitanian toadfish: sexual dimorphism and hormonal control

The members of the family Batrachoididae produce sounds associated with courtship and agonistic interactions. While long mating calls are only produced by nesting males, agonistic short duration grunts have been recorded from toadfishes and midshipmen in both males (nesting or not) and females. Sound production results from the contraction of paired sonic muscles attached to the walls of the swimbladder, which cause a rapid variation in swimbladder volume and internal pressure. Both sonic muscle growth and sonic fibre morphology have been shown to be androgen sensitive in batrachoidids

Water calcium concentration modifies whole-body calcium uptake in sea bream larvae during short-term adaptation to altered salinities

Whole-body calcium uptake was studied in gilthead sea bream larvae (9–83·mg) in response to changing environmental salinity and [Ca2+]. Calcium uptake increased with increased fish size and salinity. Fish exposed to calcium-enriched, diluted seawater showed increased calcium uptake compared with fish in diluted seawater alone. Calcium uptake was unchanged in Na+- enriched, diluted seawater. Overall, [Ca2+], and not salinity/osmolarity per se, appears to be the main factor contributing to calcium uptake. By contrast, drinking was reduced by a decrease in salinity/osmolarity but was little affected by external [Ca2+]. Calculations of the maximum contribution from drinking-associated calcium uptake showed that it became almost insignificant (less than 10%) through a strong decrease in drinking rate at low salinities (0–8‰). Diluted seawater enriched in calcium to the concentration present in full-strength seawater (i.e. constant calcium, decreasing salinity) restored intestinal calcium uptake to normal. Extra-intestinal calcium uptake also benefited from calcium addition but to a lesser extent

Liderazgo transformacional y su relación con la visión compartida y aprendizaje organizativo de los colaboradores de Manpower – Chiclayo 2017

La investigación realizada se ha enfocado en el estudio de la relación entre el liderazgo transformacional con la visión compartida y el aprendizaje organizativo de los colaboradores de la empresa Manpower en la ciudad de Chiclayo. Para ello se tomó una muestra del total de trabajadores que fueron en total 83 divididos en las cuatro áreas de la empresa (Logística, Trade marketing, Ingeniería, Minería y Ambiente y Administrativos). Ellos respondieron a un cuestionario adaptado y elaborado para medir las tres variables en estudio; el tipo de investigación tuvo un enfoque cuantitativo de nivel correlacional, no experimental y transversal. Los resultados indicaron que el liderazgo transformacional se relaciona de forma positiva tanto con la visión compartida como con el aprendizaje organizativo. Estos resultados confirman la importancia del liderazgo transformacional y que, según los resultados hallados en cada una de las dimensiones, invita a una revisión profunda del significado de los conceptos estudiados que permiten fortalecer la organización a miras de establecerse como una empresa competitiva. Finalmente, el modelo teórico analizado queda como un aporte para investigaciones que pretendan seguir el mismo fin

Nemo through the looking-glass: a commentary on Desjardins & Fernald

info:eu-repo/semantics/publishedVersio

Production of activated carbon cloth with controlled structure

The production of micro and mesoporous activated carbon cloth (ACC) from commercial acrylic textile fibres by physical activation with carbon dioxide and the addition of boric acid and sodium hydrogen phosphate as impregnants is reported. The use of sodium hydrogen phosphate leads to samples with greater mesopore volume whereas other ACC production conditions studied mainly result in microporous materials. This work demonstrates that it is possible to produce carbon materials from a commercial acrylic textile cloth with the maintenance of the precursor shape, as shown by scanning electron microscopy (SEM). The materials are formed from layers of aromatic sheets that in a nanoscale resemble graphite and X-ray diffraction studies indicate microcrystallites with dimensions between 5.9 and 7.6 nm for La (width) and between 2.4 and 2.7 nm for Lc (height), corresponding to 7 to 8 parallel graphene layers