Stable isotope geochemistry and formation mechanisms of quartz veins; Extreme paleoaltitudes of the Central Alps in the Neogene

Quartz veins ranging in size from less than 50 cm length and 5 cm width to greater than 10 m in length and 5 m in width are found throughout the Central Swiss Alps. In some cases, the veins are completely filled with milky quartz, while in others, sometimes spectacular void-filling quartz crystals are found. The style of vein filling and size is controlled by host rock composition and deformation history. Temperatures of vein formation, estimated using stable isotope thermometry and mineral equilibria, cover a range of 450 degrees C down to 150 degrees C. Vein formation started at 18 to 20 Ma and continued for over 10 My. The oxygen isotope values of quartz veins range from 10 to 20 permil, and in almost all cases are equal to those of the hosting lithology. The strongly rock-buffered veins imply a low fluid/rock ratio and minimal fluid flow. In order to explain massive, nearly morromineralic quartz formation without exceptionally large fluid fluxes, a mechanism of differential pressure and silica diffusion, combined with pressure solution, is proposed for early vein formation. Fluid inclusions and hydrous minerals in late-formed veins have extremely low delta D values, consistent with meteoric water infiltration. The change from rock-buffered, static fluid to infiltration from above can be explained in terms of changes in the large-scale deformation style occurring between 20 and 15 Ma. The rapid cooling of the Central Alps identified in previous studies may be explained in part, by infiltration of cold meteoric waters along fracture systems down to depths of 10 km or more. An average water flux of 0.15 cm 3 cm(-2)yr(-1) entering the rock and reemerging heated by 40 degrees C is sufficient to cool rock at 10 km depth by 100 degrees C in 5 million years. The very negative delta D values of < -130 permil for the late stage fluids are well below the annual average values measured in meteoric water in the region today. The low fossil delta D values indicate that the Central Alps were at a higher elevation in the Neogene. Such a conclusion is supported by an earlier work, where a paleoaltitude of 5000 meters was proposed on the basis of large erratic boulders found at low elevations far from their origin.

Endothelial nitric oxide synthase gene transfer restores endothelium-dependent relaxations and attenuates lesion formation in carotid arteries in apolipoprotein E-deficient mice.

Nitric oxide (NO) and monocyte chemoattractant protein-1 (MCP-1) exert partly opposing effects in vascular biology. NO plays pleiotropic vasoprotective roles including vasodilation and inhibition of platelet aggregation, smooth muscle cell proliferation, and endothelial monocyte adhesion, the last effect being mediated by MCP-1 downregulation. Early stages of arteriosclerosis are associated with reduced NO bioactivity and enhanced MCP-1 expression. We have evaluated adenovirus-mediated gene transfer of human endothelial NO synthase (eNOS) and of a N-terminal deletion (8ND) mutant of the MCP-1 gene that acts as a MCP-1 inhibitor in arteriosclerosis-prone, apolipoprotein E-deficient (ApoE(-/-)) mice. Endothelium-dependent relaxations were impaired in carotid arteries instilled with a noncoding adenoviral vector but were restored by eNOS gene transfer (p < 0.01). A perivascular collar was placed around the common carotid artery to accelerate lesion formation. eNOS gene transfer reduced lesion surface areas, intima/media ratios, and macrophage contents in the media at 5-week follow-up (p < 0.05). In contrast, 8ND-MCP-1 gene transfer did not prevent lesion formation. In conclusion, eNOS gene transfer restores endothelium-dependent vasodilation and inhibits lesion formation in ApoE(-/-) mouse carotids. Further studies are needed to assess whether vasoprotection is maintained at later disease stages and to evaluate the long-term efficacy of eNOS gene therapy for primary arteriosclerosis.

Role of cytokines in the formation and downregulation of hepatic circumoval granulomas and hepatic fibrosis in Schistosoma mansoni-infected mice

Schistosoma mansoni infections are associated with a strong Th2 cytokine response. Treatment of mice with IL-12 or anti-IL-2 or anti-IL-4 before i.v. injection of eggs increased IFN-gamma production and downregulated Th2 responses and pulmonary granuloma size. Conversely, anti-IFN-gamma antibody treatment increased Th2 responses and granuloma size. Similar manipulation produced less dramatic results in infected mice. However, sensitization of mice with eggs + IL-12 before infection augmented the Th1 response and decreased Th2 cytokines, granuloma size and fibrosis. Antisera to IFN-gamma, TNF-alpha or IL-12 during IL-12-egg immunization partly restored granuloma size and fibrosis following infection. Variations in the size of granulomas in acute (8 week) infections may be influenced primarily by the number and state of activation of T cells. In chronic (12-16 week) infections immunologic downmodulation proceeded normally in mice without functional CD8+ cells and in IFN-gamma KO mice but not in B cell KO (muMT) mice or in mice deficient in FcR expression in spite of the fact that these mice downregulated their T cell and cytokine responses. It is evident that the participation of cytokines in granuloma formation and regulation is complicated and that the mechanisms controlling both these phenomena are likely to involve both T cells and antibody/FcR interactions.

Induction of protective immunity against Schistosoma mansoni infection by antigens purified from PIII, a fraction of adult worm, associated to the downregulation of granuloma formation

This study was performed in order to define Schistosoma mansoni antigens able to function as modulator agents in BALB/c mice granulomatous hypersensitivity to parasite egg. The antigens P-24, P-35 and P-97 were purified by affinity chromatography from a fraction of S. mansoni adult worm antigenic preparation, denominated PIII, involved in the inhibition of granulomatous response to eggs. Immunization of mice with these antigens, in the presence of Corynebacterium parvum and Al(OH)3 as adjuvant, induced a significant protection degree against challenge infection, as observed by the decrease on worm burden recovered from portal system. In vitro blastogenesis assays revealed that purified antigens were able to induce significant proliferation of spleen cells from S. mansoni-infected mice. This protection was correlated to significant decrease in granuloma size induced by PIII. From these results, we concluded that PIII preparation contains antigens capable of mediating protective anti-parasite immunity and down-regulating granulomatous hypersensitivity to S. mansoni eggs.

Hemispheric processing of differently valenced and self-relevant attachment words in middle-aged married and separated individuals

The reliance in experimental psychology on testing undergraduate populations with relatively little life experience, and/or ambiguously valenced stimuli with varying degrees of self-relevance, may have contributed to inconsistent findings in the literature on the valence hypothesis. To control for these potential limitations, the current study assessed lateralised lexical decisions for positive and negative attachment words in 40 middle-aged male and female participants. Self-relevance was manipulated in two ways: by testing currently married compared with previously married individuals and by assessing self-relevance ratings individually for each word. Results replicated a left hemisphere advantage for lexical decisions and a processing advantage of emotional over neutral words but did not support the valence hypothesis. Positive attachment words yielded a processing advantage over neutral words in the right hemisphere, while emotional words (irrespective of valence) yielded a processing advantage over neutral words in the left hemisphere. Both self-relevance manipulations were unrelated to lateralised performance. The role of participant sex and age in emotion processing are discussed as potential modulators of the present findings.

Internalization of components of the host cell plasma membrane during infection by Trypanosoma cruzi

Epimastigote and trypomastigote forms of Trypanosoma cruzi attach to the macrophage surface and are internalized with the formation of a membrane bounded vacuole, known as the parasitophorous vacuole (PV). In order to determine if components of the host cell membrane are internalized during formation of the PV we labeled the macrophage surface with fluorescent probes for proteins, lipids and sialic acid residues and then allowed the labeled cells to interact with the parasites. The interaction process was interrupted after 1 hr at 37ºC and the distribution of the probes analyzed by confocal laser scanning microscopy. During attachment of the parasites to the macrophage surface an intense labeling of the attachment regions was observed. Subsequently labeling of the membrane lining the parasitophorous vacuole containing epimastigote and trypomastigote forms was seen. Labeling was not uniform, with regions of intense and light or no labeling. The results obtained show that host cell membrane lipids, proteins and sialoglycoconjugates contribute to the formation of the membrane lining the PV containing epimastigote and trypomastigote T. cruzi forms. Lysosomes of the host cell may participate in the process of PV membrane formation.

Chemical and carbon isotopic evolution of hydrocarbons during prograde metamorphism from 100°C to 550°C: Case study in the Liassic black shale formation of Central Swiss Alps

Hydrocarbon distributions and stable isotope ratios of carbonates (delta(13)C(car), delta(18)O(car)), kerogen (delta(13)C(ker)), extractable organic matter (delta(13)C(EOM)) and individual hydrocarbons of Liassic black shale samples from a prograde metamorphic sequence in the Swiss Alps were used to identify the major organic reactions with increasing metamorphic grade. The studied samples range from the diagenetic zone (< 100 degrees C) to amphibolite facies (similar to 550 degrees C). The samples within the diagenetic zones (< 100 and 150 degrees C) are characterized by the dominance of C-< 20 n-alkanes, suggesting an origin related with marine and/or bacterial inputs. The metamorphic samples (200 to 550 degrees C) have distributions significantly dominated by C-12 and C-13 n-alkanes, C-14, C-16 and C-18 n-alkylcyclopentanes and to a lesser extend C-15, C-17 and C-21 n-alkylcyclohexanes. The progressive C-13-enrichment (up to 3.9 parts per thousand) with metamorphism of the C-> 17 n-alkanes suggests the occurrence of cracking reactions of high molecular weight compounds. The isotopically heavier (up to 5.6 parts per thousand) C-< 17 n-alkanes in metamorphic samples are likely originated by thermal degradation of long-chain homologous with preferential release of isotopically light C-1 and C-2 radicals. The dominance of specific even C-number n-alkylcyclopentanes suggests an origin related to direct cyclization mechanism (without decarboxylation step) of algal or bacterial fatty acids occurring in reducing aqueous metamorphic fluid conditions. The regular increase of the concentrations of n-alkylcycloalkanes vs. C-> 13 n-alkanes with metamorphism suggests progressive thermal release of kerogen-linked fatty acid precursors and degradation of n-alkanes. Changes of the steroid and terpenoid distributions are clearly related to increasing metamorphic temperatures. The absence of 18 alpha(H)-22,29,30-trisnorneohopane (Ts), the occurrence of 17 beta(H)-trisnorhopane, 17 beta(H), 21 alpha(H)-hopanes in the C-29 to C-31 range and 5 alpha(H),14 alpha(H),17 alpha(H)-20R C-27, C-29 steranes in the low diagenetic samples (< 100 degrees C) are characteristic of immature bitumens. The higher thermal stress within the upper diagenetic zone (150 degrees C) is marked by the presence of Ts, the disappearance of 17 beta(H)-trisnorhopane and thermodynamic equilibrium of the 22S/(22S + 22R) homohopane ratios. The increase of the alpha alpha alpha-sterane 20S/(20S + 20R) and 20R beta beta/(beta beta + alpha alpha) ratios (from 0.0 to 0.55 and from 0.0 to 0.40, respectively) in the upper diagenetic zone indicates the occurrence of isomerization reactions already at < 150 degrees C. However, the isomerization at C-20 (R -> S) reaches thermodynamic equilibrium values already at the upper diagenesis (similar to 150 degrees C) whereas the epimerisation at C-14 and C-17 (alpha alpha ->beta beta) arrives to constant values in the lower anchizone (similar to 200 degrees C). The ratios Ts vs. 17 alpha(H)-22,29,30-trisnorneohopane [(Ts/(Ts + Tm)] and 18 alpha(H)-30-norneohopane (C29Ts) vs. 17 alpha(H),21 beta(H)-30-norhopane [C29Ts/(C29Ts + C-29)] increase until the medium anchizone (200 to 250 degrees C) from 0.0 to 0.96 and from 0.0 to 0.44, respectively. An opposite trend owards lower values is observed in the higher metamorphic samples. The occurrence of specific hydrocarbons (e.g., n-alkylcyclopentanes, cadalene, hydrogenated aromatic compounds) in metamorphic samples points to kerogen degradation reactions most probably occurring in the presence of water and under reducing conditions. The changes of hydrocarbon distributions and carbon isotopic compositions of n-alkanes related to metamorphism suggest that the organic geochemistry may help to evaluate the lowest grades of prograde metamorphism. Copyright (c) 2005 Elsevier Ltd.

Higher education as formation of the self and citizenship: an ethnography of the University Students from Amman, Jordan

My interest in higher education and citizenship in the Middle East at large and in Jordan in particular is fostered by some of the reflections Eickelman proposed (1992). Being a quite recent phenomenon, intimately linked with the more general topic of state formation it seemed to me more suitable to study it in a little country with a recent history (a field study left almost unexplored until now as far as Jordan is concerned, to the best of my knowledge, since Antoun 1994 focuses on the migration as a quest for higher education). The process of state formation in Jordan is quite studied. I thus intended to study the higher education policies as an attempt both to create a national citizenry and more recently as a way of controlling the more problematic part of the population (youth, which constitutes more than the double of the population. See UNDP and Ministry of Planning 2000). How do the young students enter the university system, and in which way does this system work? How is this system designed, in order to retain social control of the students (since they are usually perceived to be a factor of social and political instability, as in Iran or in Egypt)? Is there any significant difference between different faculties? And if so, why? My conclusions at this stage are that the university system is an integral part of the survival of the regime. The system works quite well, and Jordan has one of the best educational position in the region. Yet there are important distinctions to be made: the access to the better faculties is socially selective while the less valued faculties are left to the poorer and less wealthy youth. This results in a different treatment of the students and of the courses that I analysed. In the better faculties the teaching standards are quite high, and the relationship between professors and students is almost on a same-level base, while in the less privileged faculties the opposite is true. Thus we can observe a concrete politics of divide et impera intended to split the youth in two. For the more privileged there are some freedoms, both within and outside classes, designed I guess at forging them as autonomous individuals. On the opposite the less privileged are kept under tight control, even if also these students are a privileged category among youth at large.

Quality Of Attachment, Perinatal Risk, And Mother-Infant Interaction In A High-Risk Premature Sample

Thirty-three families, each with a premature infant born less than 33 gestational weeks, were observed in a longitudinal exploratory study. Infants were recruited in a neonatal intensive care unit, and follow-up visits took place at 4 months and 12 months of corrected age. The severity of the perinatal problems was evaluated using the Perinatal Risk Inventory (PERI; A.P. Scheiner & M.E. Sexton, 1991). At 4 months, mother infant play interaction was observed and coded according to the CARE-index (P.M. Crittenden, 2003); at 12 months, the Strange Situation Procedure (SSP; M.D.S. Ainsworth, M.C. Blehar, E. Waters. & S. Wall, 1978) was administered. Results indicate a strong correlation between the severity of perinatal problems and the quality of attachment at 12 months. Based on the PERI, infants with high medical risks more frequently tended to be insecurely attached. There also was a significant correlation between insecure attachment and dyadic play interaction at 4 months (i.e., maternal controlling behavior and infant compulsive compliance). Moreover, specific dyadic interactive patterns could be identified as protective or as risk factors regarding the quality of attachment. Considering that attachment may have long-term influence on child development, these results underline the need for particular attention to risk factors regarding attachment among premature infants.