Farmer–herder conflicts and water governance in a semi-arid region of Africa
Sedentary farmers in the Volta Basin are endangering the activity of transhumant herders relying on grazing ranges between 9° and 11°N. Despite mutual benefits, farmers try to deny them access to water and thereby the possibility to graze their stock on crop residues. This new behaviour is changing the geographical distribution of traditional activities and risks endangering herding activity, a leading economic resource in these regions. Meeting livestock watering requirements is thus a matter of local conflict resolution and good governance. Countries should be encouraged to adopt legislation to maintain or even promote the mobility of herding activities.
A chacun son onchocercose
La lutte menee de nos jours par l'OMS contre les simulies se justifie pleinement dans la mesure ou elle protege de l'onchocercose les hommes qui investissent a nouveau les vallees, aussi longtemps qu'ils ne sont pas parvenus a reconstituer la double barriere humaine et ecologique seule a meme, dans les conditions actuelles de les preserver durablement, sinon toujours de l'infection, du moins des formes graves, intolerables, de la maladie
Tumor Autonomous Effects of Vitamin D Deficiency Promote Breast Cancer Metastasis.
Patients with breast cancer (BCa) frequently have preexisting vitamin D deficiency (low serum 25-hydroxyvitamin D) when their cancer develops. A number of epidemiological studies show an inverse association between BCa risk and vitamin D status in humans, although some studies have failed to find an association. In addition, several studies have reported that BCa patients with vitamin D deficiency have a more aggressive molecular phenotype and worse prognostic indicators. However, it is unknown whether this association is mechanistically causative and, if so, whether it results from systemic or tumor autonomous effects of vitamin D signaling. We found that ablation of vitamin D receptor expression within BCa cells accelerates primary tumor growth and enables the development of metastases, demonstrating a tumor autonomous effect of vitamin D signaling to suppress BCa metastases. We show that vitamin D signaling inhibits the expression of the tumor progression gene Id1, and this pathway is abrogated in vitamin D deficiency in vivo in 2 murine models of BCa. These findings are relevant to humans, because we discovered that the mechanism of VDR regulation of Inhibitor of differentiation 1 (ID1) is conserved in human BCa cells, and there is a negative correlation between serum 25-hydroxyvitamin D levels and the level of ID1 in primary tumors from patients with BCa.