Influence of main forcing affecting the Tagus turbid plume under high river discharges using MODIS imagery

The role of river discharge, wind and tide on the extension and variability of the Tagus River plume was analyzed from 2003 to 2015. This study was performed combining daily images obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor located onboard the Aqua and Terra satellites. Composites were generated by averaging pixels with the same forcing conditions. River discharge shows a strong relation with the extension of the Tagus plume. The plume grows with the increasing river discharge and express a two day lag caused by the long residence time of water within the estuary. The Tagus turbid plume was found to be smaller under northerly and easterly winds, than under southerly and westerly winds. It is suggested that upwelling favoring winds provoke the offshore movement of the plume material with a rapidly decrease in turbidity values whereas downwelling favoring winds retain plume material in the north coast close to the Tagus mouth. Eastern cross-shore (oceanward) winds spread the plume seaward and to the north following the coast geometry, whereas western cross-shore (landward) winds keep the plume material in both alongshore directions occupying a large part of the area enclosed by the bay. Low tides produce larger and more turbid plumes than high tides. In terms of fortnightly periodicity, the maximum plume extension corresponding to the highest turbidity is observed during and after spring tides. Minimum plume extension associated with the lowest turbidity occurs during and after neap tides.

Human papillomavirus genotypes in rural Mozambique

We studied the genotype distribution of cervical human papillomavirus (HPV) infections in an age-stratified sample of 262 women in Mozambique using the PGMYO9-PGMY11 primer system in a reverse line-blot strip-based assay with high sensitivity in type-specific amplification. Despite the low precision of the estimates, we found that HPV-16 was not the dominant type. Instead, HPV 35 was the most commonly identified genotype among HPV-positive women (16/96 [17%]) and women with cervical neoplasia (7/23 [30%]). Certain genotypes might have been under-detected in previous studies, and type-specific HPV distributions might vary across populations. Therefore, the estimated proportion of cervical neoplasia that could be prevented by an HPV-16-based vaccine could be lower than expected.

A preliminary study of breast-feeding and maternal symptomatology

The association between breast-feeding status and maternal health is examined. A survey questionnaire was presented via the World Wide Web. Self-reports of 168 breast-feeding and 65 weaned mothers between 4 and 208 weeks postpartum were compared for physician visits, symptomatology, and Perceived Stress Scale scores in the last month. Breast-feeding was associated with fewer physician visits and symptoms and less perceived stress. Moreover, the longer a woman breast-fed before she weaned, the fewer the symptoms and less stress she reported. Breast-feeding is associated with better maternal health both during the breast-feeding period and after weaning. Further research on the effects on maternal health of breast-feeding is indicated. Future prospective longitudinal investigations should address the possible inhibition of lactation by stress and physiological mechanisms that may link breast-feeding and weaning with maternal health.

[Teaching and health: a biological view]

Living systems are structure determined systems. Teaching is never feasible, but learning is inevitable, a comment by an observer about some aspect of the constant changes occurring while life goes on. Teachers are all those who open up spaces for conviviality and allow congruent changes to take place. There are no instructive interactions in nature. Health and the biology of living systems are phenomena studied in different domains. What is healthy or unhealthy for humans, is defined by human culture. As biological phenomena, health and disease are relational configurations of the organism and its medium. From this perspective, individual health is a social phenomenon.

Immaturity, ageing and oral tolerance

Founding studies of cellular immunology emphasized that tolerance to allografts could only be achieved early in the embryonic or neonatal period, suggesting that the establishment of self-tolerance, a main event in the organization of the immune system, would necessarily take place in immature hosts. Contradicting these ideas, oral tolerance is a common, daily phenomenon, easily achieved by a physiological route in adult immunocompetent animals. Furthermore, there is solid evidence that, after the neonatal period, the susceptibility to oral tolerance induction also wanes and that it may be restored by adoptive transfer of cells from young hosts. These findings are briefly reviewed here to emphasize that immunological activity is a continuous and ongoing epigenesis extending throughout the entire life of the organism, far beyond the early phases of ontogenesis.

Polyclonal activation of B lymphocytes during experimental infection with Schistosoma mansoni

A significant polyclonal activation of B lymphocytes was observed during experimental infection of C57BL/10J mice with Schistosoma mansoni. The isotypic pattern of this expansion, assessed by the Protein-A plaque-forming cell method, was compared with and found to differ from those occurring after infection by Trypanosoma cruzi or injection of bacterial LPS. In the infection of S. mansoni an early expansion of most immunoglobulin isotypes occurs together with a late, sustained expansion of IgG1-secreting cells. High levels of polyclonal B cell activation were observed after adoptive transfer of spleen cells from infected mice to isogenic recipients pre-treated with hydroxyurea.