Interplay between n-3 and n-6 long-chain polyunsaturated fatty acids and the endocannabinoid system in brain protection and repair.

The brain is enriched in arachidonic acid (ARA) and docosahexaenoic acid (DHA), long-chain polyunsaturated fatty acids (LCPUFA) of the n-6 and n-3 series, respectively. Both are essential for optimal brain development and function. Dietary enrichment with DHA and other long-chain n-3 PUFA, such as eicosapentaenoic acid (EPA) have shown beneficial effects on learning and memory, neuroinflammatory processes and synaptic plasticity and neurogenesis. ARA, DHA and EPA are precursors to a diverse repertoire of bioactive lipid mediators, including endocannabinoids. The endocannabinoid system comprises cannabinoid receptors, their endogenous ligands, the endocannabinoids, and their biosynthetic and degradation enzymes. Anandamide (AEA) and 2-archidonoylglycerol (2-AG) are the most widely studied endocannabinoids, and are both derived from phospholipid-bound ARA. The endocannabinoid system also has well established roles in neuroinflammation, synaptic plasticity and neurogenesis, suggesting an overlap in the neuroprotective effects observed with these different classes of lipids. Indeed, growing evidence suggests a complex interplay between n-3 and n-6 LCPUFA and the endocannabinoid system. For example, long-term DHA and EPA supplementation reduces AEA and 2-AG levels, with reciprocal increases in levels of the analogous endocannabinoid-like DHA and EPA-derived molecules. This review summarises current evidence of this interplay and discusses the therapeutic potential for brain protection and repair

Mantle strength of the San Andreas fault system and the role of mantle-crust feedbacks

In lithospheric-scale strike-slip fault zones, upper crustal strength is well constrained from borehole observations and fault rock deformation experiments, but mantle strength is less well known. Using peridotite xenoliths, we show that the upper mantle below the San Andreas fault system (California, USA) is dry and its maximum resolved shear stress (5–9 MPa) is similar to the shear strength of the upper, seismogenic portion of the fault. These results do not fit with any existing lithospheric strength profile. We propose the “lithospheric feedback” model in which the upper crust and lithospheric mantle act together as an integrated system. Mantle flow controls displacement and loads the upper crust. In contrast, the upper crust controls the stress magnitude in the integrated system. Crustal rupture transiently increases strain rate in the upper mantle below the strike-slip fault, leading to viscous strain localization. The lithospheric feedback model suggests that lithospheric strength is a dynamic property— varying in space and time—in actively deforming regions

Tracking the late Paleozoic to early Mesozoic margin of northern Gondwana in the Hellenides: paleotectonic constraints from U–Pb detrital zircon ages

We report new detrital zircon U–Pb ages of nine quartzites sampled along the Phyllite–Quartzite unit sensu stricto (PQ unit s.s.), in the high-pressure belt of the southern Hellenides. The detrital zircon age spectra are dominated by two significant age peaks at ca. 600 and ca. 1000 Ma, which are typical for an east Gondwana provenance. The absence of zircons of Carboniferous–Triassic ages suggests that the depositional environment was isolated from Variscan and early Mesozoic sources. Our data are in support of paleogeographic configurations placing the protolith of the PQ unit s.s. south of the Paleotethys ocean and along the northern Gondwana margin. The zircon age spectra do not show significant variations with respect to the tectonostratigraphic position within the PQ unit s.s. and the position along the high-pressure belt. Combining the new (this study) with published detrital zircon ages, we suggest that the siliciclastic metasediments of the PQ unit s.s. on Crete, Kythera, and the Peloponnesus have a common paleogeographic origin

Normas percebidas por estudantes universitários de três carreiras, da área da saúde, sobre o uso de drogas entre seus pares Normas percibidas por estudiantes universitarios sobre el uso de drogas entre sus pares, en tres áreas académicas de la salud Perceived norms among university students of three health courses for drug use among peers

O presente estudo abordou alunos de segundo e terceiro anos de três cursos da área da saúde tendo como objetivos identificar a estimativa do uso de drogas por estudantes universitários (norma percebida), a frequência de uso na presente amostra (norma real), comparar as estimativas com a frequência e identificar condições nas quais as drogas são usadas. Os estudantes superestimaram o uso, por seus pares, de tabaco, maconha e cocaína, na vida e nos últimos 12 meses. O álcool foi exceção. A porcentagem de uso relatada pelos estudantes da amostra e a estimativa do uso por estudantes em geral foram muito próximas. As substâncias são mais consumidas em festas e na companhia de colegas da universidade. Os dados foram interpretados à luz da Teoria das Normas Sociais, da Atribuição de Causalidade e da Normalização.<br>El presente estudio tuvo como participantes a los alumnos del segundo e tercero año de tres cursos académicos de la Salud; el objetivo fue identificar la estimativa del uso de drogas (norma percibida), la frecuencia del uso (norma real), comparar las estimativas con la frecuencia y las condiciones en las cuales se usan las drogas. Se encontró que los estudiantes sobreestimaron el uso de sus pares en lo que se refiere al uso de tabaco, marihuana y cocaína, en alguna vez en la vida y el los últimos 12 meses. El alcohol fue la excepción, ya que el porcentaje de uso y la estimativa estuvieron muy próximos. Las sustancias son consumidas con mayor frecuencia en fiestas y en compañía de sus pares universitarios. Los datos fueran interpretados según el marco la Teoría de las Normas Sociales, de la Atribución de Causalidad y de la Normalización.<br>The present study interviewed second- and third-year students of three health courses to identify university students' estimates for drug use (perceived norm), the rate of drug use among the subjects (real norm); compare the estimates with the actual frequency; and identify in what conditions the drugs are used. Students overestimated their peers' use of tobacco, marijuana and cocaine in life and over the last 12 months. Alcohol was an exception. The rate values reported by sample students and the general estimated use were rather close. Drugs are usually consumed at parties and among friends from the university. Data analysis was performed in the light of the Social Norms Theory, Causal Attribution and Normalization