Portrait du journalisme à la pige à l’heure de la convergence

Cette recherche explore le journalisme indépendant dans le contexte contemporain de convergences socio-techno-médiatiques. Je questionne ici l’existence d’un lien entre les pratiques de pige et de convergence en journalisme et son apport dans le développement de l’univers journalistique. Il s’agit d’une étude exploratoire et empirique, consacrée aux expériences des journalistes indépendants et développée autour des concepts de tactique, résistance, liberté et gouvernance. J’ai constitué ainsi un cadre théorique à partir de l’articulation théorique de Michel Foucault relative au pouvoir. Je défends l’idée selon laquelle la pige et la convergence en journalisme sont chacun des mouvements libres qui coexistent et qui, ensemble, constituent une force motrice pour le dispositif de pouvoir que le journalisme représente dans un système démocratique avancé. La liberté de mouvement des journalistes indépendants leur permet de mener plus loin le journalisme dans le contexte actuel de convergences et d’augmenter l’horizon d’applicabilité de ce domaine de la communication de masse.This research explores the independent journalism in the contemporary context of socio-technological and media convergences. Here I question the existence of a connection between freelance and convergence practices in journalism, and its contribution to the development of the journalistic world. This is an exploratory and empirical study, focused on freelancers’ experiences and developed around the concepts of tactics, resistance, freedom and governance. I have thus formulated a theoretical framework, supported by Michel Foucault’s accounts related to power. I argue that freelancing and convergence are free movements, co-existing and forming a driving force for the institution of power represented by journalism in advanced democracies. In this current context of convergences, this freedom allows freelancers to challenge the limits of journalism, hence increasing the scope of applications within this greater realm of mass communication

Basis for the gain and subsequent dilution of epidermal pigmentation during human evolution: The barrier and metabolic conservation hypotheses revisited

The evolution of human skin pigmentation must address both the initial evolution of intense epidermal pigmentation in hominins, and its subsequent dilution in modern humans. While many authorities believe that epidermal pigmentation evolved to protect against either ultraviolet B (UV-B) irradiation-induced mutagenesis or folic acid photolysis, we hypothesize that pigmentation augmented the epidermal barriers by shifting the UV-B dose-response curve from toxic to beneficial. Whereas erythemogenic UV-B doses produce apoptosis and cell death, suberythemogenic doses benefit permeability and antimicrobial function. Heavily melanized melanocytes acidify the outer epidermis and emit paracrine signals that augment barrier competence. Modern humans, residing in the cooler, wetter climes of south-central Europe and Asia, initially retained substantial pigmentation. While their outdoor lifestyles still permitted sufficient cutaneous vitamin D3 (VD3) synthesis, their marginal nutritional status, coupled with cold-induced caloric needs, selected for moderate pigment reductions that diverted limited nutritional resources towards more urgent priorities (=metabolic conservation). The further pigment-dilution that evolved as humans reached north-central Europe (i.e., northern France, Germany), likely facilitated cutaneous VD3 synthesis, while also supporting ongoing, nutritional requirements. But at still higher European latitudes where little UV-B breaches the atmosphere (i.e., present-day UK, Scandinavia, Baltic States), pigment dilution alone could not suffice. There, other nonpigment-related mutations evolved to facilitate VD3 production; for example, in the epidermal protein, filaggrin, resulting in reduced levels of its distal metabolite, trans-urocanic acid, a potent UV-B chromophore. Thus, changes in human pigmentation reflect a complex interplay between latitude, climate, diet, lifestyle, and shifting metabolic priorities

Fundamental questions to sun protection: A continuous education symposium on vitamin D, immune system and sun protection at the University of Zürich

Since exposure to sunlight is a main factor in the development of non-melanoma skin cancer and there are associations between malignant melanoma and short-term intense ultraviolet (UV) exposure, particularly burning in childhood, strict protection from UV-radiation is recommended. However, up to 90% of all requisite vitamin D has to be formed within the skin through the action of the sun—a serious problem, for a connection between vitamin D deficiency, demonstrated in epidemiological studies, and various types of cancer and other diseases has been confirmed. A UVB-triggered skin autonomous vitamin D3 synthesis pathway has recently been described, producing the active Vitamin D metabolite calcitriol. This cutaneous vitamin D3 pathway is unique. Keratinocytes and dendritic cells can convert vitamin D to calcitriol. Cutaneous T cells activated in the presence of calcitriol express the chemokine receptor CCR10 attracting them to the chemokine CCL27 that keratinocytes express selectively in the epidermis, and migrate from dermal layers of the skin to the epidermis under UV radiation. Thus, calcitriol has endocrine roles beyond its calciotropic action, including cell growth and cancer prevention. Therefore, strict sun protection procedures to prevent skin cancer may induce the risk of vitamin D deficiency. As there is evidence that the protective effect of less intense solar radiation can outweigh its mutagenic effect, better balanced approaches to sun protection should be sought