Photon spectrum produced by the late decay of a cosmic neutrino background

We obtain the photon spectrum induced by a cosmic background of unstable neutrinos. We study the spectrum in a variety of cosmological scenarios and also we allow for the neutrinos having a momentum distribution (only a critical matter-dominated universe and neutrinos at rest have been considered until now). Our results can be helpful when extracting bounds on neutrino electric and magnetic moments from cosmic photon background observations.

Effect of olive oil on early and late events of colon carcinogenesis in rats: modulation of arachidonic acid metabolism and local prostaglandin E2 synthesis.

BACKGROUND Animal model studies have shown that the colon tumour promoting effect of dietary fat depends not only on the amount but on its fatty acid composition. With respect to this, the effect of n9 fatty acids, present in olive oil, on colon carcinogenesis has been scarcely investigated. AIMS To assess the effect of an n9 fat diet on precancer events, carcinoma development, and changes in mucosal fatty acid composition and prostaglandin (PG)E2 formation in male Sprague-Dawley rats with azoxymethane induced colon cancer. METHODS Rats were divided into three groups to receive isocaloric diets (5% of the energy as fat) rich in n9, n3, or n6 fat, and were administered azoxymethane subcutaneously once a week for 11 weeks at a dose rate of 7.4 mg/kg body weight. Vehicle treated groups received an equal volume of normal saline. Groups of animals were colectomised at weeks 12 and 19 after the first dose of azoxymethane or saline. Mucosal fatty acids were assessed at 12 and 19 weeks. Aberrant crypt foci and the in vivo intracolonic release of PGE2 were assessed at week 12, and tumour formation at week 19. RESULTS Rats on the n6 diet were found to have colonic aberrant crypt foci and adenocarcinomas more often than those consuming either the n9 or n3 diet. There were no differences between the rats on the n9 and n3 diets. On the other hand, administration of both n9 and n3 diets was associated with a decrease in mucosal arachidonate concentrations as compared with the n6 diet. Carcinogen treatment induced an appreciable increase in PGE2 formation in rats fed the n6 diet, but not in those fed the n3 and n9 diets. CONCLUSIONS Dietary olive oil prevented the development of aberrant crypt foci and colon carcinomas in rats, suggesting that olive oil may have chemopreventive activity against colon carcinogenesis. These effects may be partly due to modulation of arachidonic acid metabolism and local PGE2synthesis.

Cholesterol transport from late endosomes to the Golgi regulates t-SNARE trafficking, assembly, and function

Cholesterol regulates plasma membrane (PM) association and functioning of syntaxin-4 and soluble N-ethylmaleimide-sensitive fusion protein 23 (SNAP23) in the secretory pathway. However, the molecular mechanism and cellular cholesterol pools that determine the localization and assembly of these target membrane SNAP receptors (t-SNAREs) are largely unknown. We recently demonstrated that high levels of annexin A6 (AnxA6) induce accumulation of cholesterol in late endosomes, thereby reducing cholesterol in the Golgi and PM. This leads to an impaired supply of cholesterol needed for cytosolic phospholipase A2 (cPLA2) to drive Golgi vesiculation and caveolin transport to the cell surface. Using AnxA6-overexpressing cells as a model for cellular cholesterol imbalance, we identify impaired cholesterol egress from late endosomes and diminution of Golgi cholesterol as correlating with the sequestration of SNAP23/syntaxin-4 in Golgi membranes. Pharmacological accumulation of late endosomal cholesterol and cPLA2 inhibition induces a similar phenotype in control cells with low AnxA6 levels. Ectopic expression of Niemann-Pick C1 (NPC1) or exogenous cholesterol restores the location of SNAP23 and syntaxin-4 within the PM. Importantly, AnxA6-mediated mislocalization of these t-SNAREs correlates with reduced secretion of cargo via the SNAP23/syntaxin-4¿dependent constitutive exocytic pathway. We thus conclude that inhibition of late endosomal export and Golgi cholesterol depletion modulate t-SNARE localization and functioning along the exocytic pathway.

Roman amphora trade across the Straits of Gibraltar: An ancient 'anti-economic practice'?

Summary. Olive oil and fish products from the south of Hispania and North Africa played an important role in the Roman economy. The authors call attention to the asymmetrical distribution of archaeological data available on this subject, in particular the location of amphora kilns, and try to give an explanation, based on the evolution of European archaeology in the twentieth century.

Teresa San Roman, antropologa

Después publicar de la entrevista a Ramón Valdés (v. Perifèria 5), continúa la colaboración de la revista con el Proyecto Entrevistas3. En esta ocasión los alumnos han entrevistado a la Catedrática de la UAB, Teresa San Román Espinosa. La entrevista tuvo lugar el pasado 25 de junio de 2007 en su despacho del departamento, en un ambiente muy cercano y distendido, dando como resultado un extenso pero a su vez ameno repaso por el recorrido vital e intelectual de una figura de referencia imprescindible en la antropología social española, reconocida y admirada por su trabajo de investigación con los gitanos y por su compromiso personal y profesional con una antropología aplicada e implicada.

A Mammalian Lost World in Southwest Europe during the Late Pliocene.

Over the last decades, there has been an increasing interest on the chronology, distribution and mammal taxonomy (including hominins) related with the faunal turnovers that took place around the Pliocene-Pleistocene transition [ca. 1.8 mega-annum (Ma)] in Europe. However, these turnovers are not fully understood due to: the precarious nature of the period's fossil record; the"non-coexistence" in this record of many of the species involved; and the enormous geographical area encompassed. This palaeontological information gap can now be in part bridged with data from the Fonelas P-1 site (Granada, Spain), whose faunal composition and late Upper Pliocene date shed light on some of the problems concerning the timing and geography of the dispersals.

L'àmbit temàtic de la saviesa en l'obra de Ramon Llull : Exemples extrets del Llibre de meravelles, del Romanç d'Evast e Blaquerna i del Llibre de virtuts e de pecats

Estudi de l'àmbit temàtic de la saviesa en l'obra de Ramon Llull, tot analitzant els exemples dedicats a aquest concepte.

Archaeological and archaeomagnetic dating at a site from the ager Tarraconensis (Tarragona, Spain): El Vila-sec Roman pottery

A very accurate archaeological dating of a Roman site in NE Spain (El Vila-sec) was made based on the typology of pottery artifacts. Three different phases were identifi ed with activity ranging from the mid- 1st century BC to the early-3rd century AD. Analyses of bricks from kilns at El Vila-sec produced data on their stored archaeomagnetic vector. These data were compared with the secular variation curve for the Iberian Peninsula and the SCHA.DIF.3K regional archaeomagnetic model. Both, the reference curve and the model, produced probability distributions for the final period of use for two kilns from the second archaeological phase that were not used during the third phase. At a 95% con fidence level, both time distributions cover a wide chronological range including the presumed archaeological age. Both the Iberian secular variation curve and the SCHA.DIF.3K regional model proved to be suitable models for dating the site, although on their own they do not produce a single unambiguous solution. This archaeomagnetic approach could also be applied to neighbouring archaeological sites that have an imprecise archaeological age.

El marmor de Tarraco. Explotació, utilització i comercialització de la pedra de Santa Tecla en època romana Tarraco marmor. The Quarrying, Use and Trade of Santa Tecla Stone in Roman Times

Aquest és el llibre més complet que hi ha sobre la pedra de Santa Tecla i el llisós, dos materials procedents de Tarragona i molt utilitzats en època romana. Els autors, arqueòlegs i geòlegs, caracteritzen aquestes dues varietats i presenten el panorama de les seves aplicacions, i també donen pautes per identificar-les i diferenciar-les d’altres pedres que s’hi podrien confondre, com la “portasanta” o la pedra de Buixcarró.

El poblament rural del Camp de Tarragona en època tardo-republicana (segles II-I aC)

This project consists of a study of the settlement of population during the Late Republican period in the Camp de Tarragona, an extensive agricultural plain in the shape of a crescent moon opening out towards the sea which constitutes the area of land in closest proximity to the capital, Tarraco. It does not therefore include the entirety of the ager Tarraconensis, which covered a considerably larger area. After reviewing the preceding Iberian presence in the area, the study focuses on the archaeological evidence corroborating the settlement of population referred to above and its evolution during the course of the two centuries prior to the rule of Augustus. Attention is also given to certain speciic themes, such as the centuriation of certain sectors, the presence of military checkpoints, the production of ceramics during the Republican period (at Fontscaldes and Valls) and the appearance of the irst Roman villas (El Moro and El Mas d’en Gras).

The ager tarraconensis project (right side of river Francoli) (PAT): the application of geophysical survey to identify rural Roman settlement typologies

The methodology of the ager Tarraconensis project also included geophysical surveys aiming to distinguish different categories of rural settlements. Two geophysical techniques (resistivity and magnetometry) were combined to reveal traces of unearth structures from a selection of sites identified from the field survey. Results of geophysical surveys of these seven sites as well as conclusions obtained from this approach are discussed here.