西南极南设得兰群岛中新生代火山岩基底沉积学及其大地构造制约

Livingston Island, the second island of South Shetland Island, constains Mesozoic-Cenozoic basement, Mesozoic-Cenozoic volcanic sequences, plutonic intrusions and post-subduction volcanic rocks, which document the history and evolution of an important part of the South Shetland Islands magmatic arc. The sedimentary sequence is named the Miers Bluff Formation (MBF) and is interpreted as turbidite since the first geological study on South Shetland Islands, and is interpreted as turbidite. It base and top are not exposed, but a thickness of more than 3000m has been suggested and seems plausible. The turbidite is overlain by Mid - Cretaceous volcanic rocks and intruded by Eocene tonalites. The age of the Miers Bluff Formation is poorly constrained Late Carboniferous -Early Triassic. Sedimentary Environment, tectonic setting and forming age of sedimentary rocks of the Miers Bluff Formation were discussed by means of the methods of sedimentology, petrography and geochemistry, combinig with the study of trace fossils and microfossil plants. The following conclusions are obstained. A sedimentary geological section of Johnsons Dock is made by outside measuring and watching, and then according the section, the geological map near the Spanish Antarctic station was mapped. Four pebbly mudstone layers are first distinguished, which thickness is about 10m. The pebbly mudstone is the typical rock of debris flow, and the depostional environment of pebbly mudstone may be the channel of mid fan of submarine fan. The sedimentsry structural characteristics and size analysis of sandstones show the typical sedimentary feature of turbidity flow and the Miers Bluff Formation is a deep-water turbidite (include some gravity-flow sediments). The materials of palaeocurrents suggest the continental slope dip to southeast, and indicate the provenance of turbidity sediment in the northwest area. By facies analysis, six main facies which include seven subfacies were recognized, which are formed in mid-fan and lower-fan of submarine, meanwhile, the sedimentary features of each facies and subfacies are summarized. The study of clastic composition, major elements, trace elements and rare earth elements indicates the forming setting of the Miers Bluff Formaton is active continental margin and continental island arc and the provenance is dissected magmatic arc which main composition is felsic gneiss. Many trace fossils of the whole succession were found in the turbidites of the Miers Bluff Formation. All these trace fossils are deep sea ichnofossils. There are fifteen ichnogenus, sixteen ichnospecies. Moreover, a new trace fossil was found and a new ichnogenus and new ichnospecies was proposed - Paleaichnus antarctics ichnogen, et ichnosp, nov.. Except the new ichnogenus and ichnospecies, others had been found in deep-sea flysch turbidites. Some are in mudstone and are preserved in the cast convex of overlying sandstone sole, they formed before turbidity flows occurred and belong to the high-different Graphoglyptida of fiysch mudstone. Others as Fucusopsis and Neonereites are preserved in sandstones and stand for trace assemblages after turbidity sedimentation. These trace fossils are typical members of abyssal "Nereites" ichnofacies, and provide for the depositional environment of the Miers Bluff Formation. Fairly diverse microfossil plants have been recovered from the Miers Bluff Formation, Livingston Island, including spores, pollen, acritarchs, wood fragments and cuticles. Containing a total of about 45 species (forms) of miospores, the palynofiora is quantitatively characterized by the dominance of non-striate bisaccate pollen, but spores of pteridophytes and pollen of gymnosperms are proportionate in diversity. It is somewhat comparable to the subzone C+D of the Alisporites zone of Antarctica, and the upper Craterisporites rotundus zone and the lower Polycingulatisporites crenulatus zone of Australia, suggesting a Late Triassic (possibly Norian-Rhaetian) age, as also evidenced by the sporadic occurrence of Aratrisporites and probable Classopollis as well as the complete absence of bisaccate Striatiti. The parent vegetation and paleoclimate are preliminarily deduced. At last, the paper prooses the provenance of sedimentary rocks of the Miers Bluff Formation locates in the east part to the southern Chile(or Southern South American). In the Triassic period, contrasting with New Zealand, Australia and South American of the Pacific margin of Gondwanaland, the Miers Bluff Formation is deposited in the fore-arc basin or back-arc basin of magmatic arc.

Measurement of the differential cross section for the reaction gamman-->pi- p from deuterium.

We report a measurement of the differential cross section for the gamman-->pi- p process from the CLAS detector at Jefferson Laboratory in Hall B for photon energies between 1.0 and 3.5 GeV and pion center-of-mass (c.m.) angles (thetac.m.) between 50 degrees and 115 degrees. We confirm a previous indication of a broad enhancement around a c.m. energy ([sqrt]s) of 2.1 GeV at thetac.m.=90 degrees in the scaled differential cross section s7dsigma/dt and a rapid falloff in a center-of-mass energy region of about 400 MeV following the enhancement. Our data show an angular dependence of this enhancement as the suggested scaling region is approached for thetac.m. from 70 degrees to 105 degrees.

Prenatal protease inhibitor use and risk of preterm birth among HIV-infected women initiating antiretroviral drugs during pregnancy.

BACKGROUND: Conflicting results have been reported among studies of protease inhibitor (PI) use during pregnancy and preterm birth. Uncontrolled confounding by indication may explain some of the differences among studies. METHODS: In total, 777 human immunodeficiency virus (HIV)-infected pregnant women in a prospective cohort who were not receiving antiretroviral (ARV) treatment at conception were studied. Births <37 weeks gestation were reviewed, and deliveries due to spontaneous labor and/or rupture of membranes were identified. Risk of preterm birth and low birth weight (<2500 g) were evaluated by using multivariable logistic regression. RESULTS: Of the study population, 558 (72%) received combination ARV with PI during pregnancy, and a total of 130 preterm births were observed. In adjusted analyses, combination ARV with PI was not significantly associated with spontaneous preterm birth, compared to ARV without PI (odds ratio [OR], 1.22; 95% confidence interval [CI], 0.70-2.12). Sensitivity analyses that included women who received ARV prior to pregnancy also did not identify a significant association (OR, 1.34; 95% CI, 0.84-2.16). Low birth weight results were similar. CONCLUSIONS: No evidence of an association between use of combination ARV with PI during pregnancy and preterm birth was found. Our study supports current guidelines that promote consideration of combination ARV for all HIV-infected pregnant women.

Adenosine, inflammation and asthma - a review

Adenosine is a ubiquitous molecule present in every cell of the human body. It has a wide range of physiological functions mediated predominantly through specific cell surface adenosine receptors. Adenosine has both pro- and anti-inflammatory effects and acts on inflammatory and resident immune cells and antioxidant enzymes. The elevation of adenosine in the bronchoalveolar lavage (BAL) fluid of asthmatics combined with its bronchoconstrictor effect on the airways in asthmatics has led to increased research into the contribution of adenosine in the pathophysiology of inflammation and asthma. This review looks at the airway response to adenosine and at the interaction of adenosine with mast cells and basophils.

Mast cell mediator release in nonasthmatic subjects after endobronchial adenosine challenge

Background: Adenosine 5′-monophosphate (AMP) has been shown to cause bronchoconstriction in atopic subjects but to have no effect on nonatopic nonasthmatic subjects. Endobronchial AMP challenge has previously been shown to cause mast cell mediator release in asthmatic subjects, but it is unknown whether a similar response occurs in atopic nonasthmatic and nonatopic nonasthmatic control subjects who have no response to inhalation AMP challenge.

Objective: This study examined the change in mast cell–derived products after endobronchial saline challenge and AMP challenge in subjects with and without a positive inhalation response to AMP.

Methods: Inhalation challenge with AMP challenge was performed in normal, atopic nonasthmatic, and atopic asthmatic subjects. Levels of mast cell mediators were measured after endobronchial adenosine challenge and after placebo endobronchial saline challenge.

Results: There were significant increases in histamine, tryptase, protein, and prostaglandin D2 levels (P = .02, P = .02, P = .01, and P = .01, respectively) after AMP challenge compared with after saline challenge in nonatopic nonasthmatic subjects. There was no significant increase in any mediator in either of the other 2 groups.

Conclusion: This study suggests dissociation between mediator release and bronchoconstriction in response to AMP.

Genome-wide association study identifies variants at CLU and PICALM associated with Alzheimer's disease

We undertook a two-stage genome-wide association study (GWAS) of Alzheimer's disease (AD) involving over 16,000 individuals, the most powerful AD GWAS to date. In stage 1 (3,941 cases and 7,848 controls), we replicated the established association with the apolipoprotein E (APOE) locus (most significant SNP, rs2075650, P = 1.8 x 10(-157)) and observed genome-wide significant association with SNPs at two loci not previously associated with the disease: at the CLU (also known as APOJ) gene (rs11136000, P = 1.4 x 10(-9)) and 5. to the PICALM gene (rs3851179, P = 1.9 x 10(-8)). These associations were replicated in stage 2 (2,023 cases and 2,340 controls), producing compelling evidence for association with Alzheimer's disease in the combined dataset (rs11136000, P = 8.5 x 10(-10), odds ratio = 0.86; rs3851179, P = 1.3 x 10(-9), odds ratio = 0.86).

Genetic Evidence Implicates the Immune System and Cholesterol Metabolism in the Aetiology of Alzheimer's Disease

Background: Late Onset Alzheimer's disease (LOAD) is the leading cause of dementia. Recent large genome-wide association studies (GWAS) identified the first strongly supported LOAD susceptibility genes since the discovery of the involvement of APOE in the early 1990s. We have now exploited these GWAS datasets to uncover key LOAD pathophysiological processes. Methodology: We applied a recently developed tool for mining GWAS data for biologically meaningful information to a LOAD GWAS dataset. The principal findings were then tested in an independent GWAS dataset.

Common variants at ABCA7, MS4A6A/MS4A4E, EPHA1, CD33 and CD2AP are associated with Alzheimer's disease

We sought to identify new susceptibility loci for Alzheimer's disease through a staged association study (GERAD+) and by testing suggestive loci reported by the Alzheimer's Disease Genetic Consortium (ADGC) in a companion paper. We undertook a combined analysis of four genome-wide association datasets (stage 1) and identified ten newly associated variants with P = 1 × 10(-5). We tested these variants for association in an independent sample (stage 2). Three SNPs at two loci replicated and showed evidence for association in a further sample (stage 3). Meta-analyses of all data provided compelling evidence that ABCA7 (rs3764650, meta P = 4.5 × 10(-17); including ADGC data, meta P = 5.0 × 10(-21)) and the MS4A gene cluster (rs610932, meta P = 1.8 × 10(-14); including ADGC data, meta P = 1.2 × 10(-16)) are new Alzheimer's disease susceptibility loci. We also found independent evidence for association for three loci reported by the ADGC, which, when combined, showed genome-wide significance: CD2AP (GERAD+, P = 8.0 × 10(-4); including ADGC data, meta P = 8.6 × 10(-9)), CD33 (GERAD+, P = 2.2 × 10(-4); including ADGC data, meta P = 1.6 × 10(-9)) and EPHA1 (GERAD+, P = 3.4 × 10(-4); including ADGC data, meta P = 6.0 × 10(-10)).

No Evidence that Extended Tracts of Homozygosity are Associated with Alzheimer’s Disease.

We sought to investigate the contribution of extended runs of homozygosity in a genome-wide association dataset of 1,955 Alzheimer's disease cases and 955 elderly screened controls genotyped for 529,205 autosomal single nucleotide polymorphisms. Tracts of homozygosity may mark regions inherited from a common ancestor and could reflect disease loci if observed more frequently in cases than controls. We found no excess of homozygous tracts in Alzheimer's disease cases compared to controls and no individual run of homozygosity showed association to Alzheimer's disease.

The Role of Variation at AβPP, PSEN1, PSEN2, and MAPT in Late Onset Alzheimer's Disease

Rare mutations in AßPP, PSEN1, and PSEN2 cause uncommon early onset forms of Alzheimer's disease (AD), and common variants in MAPT are associated with risk of other neurodegenerative disorders. We sought to establish whether common genetic variation in these genes confer risk to the common form of AD which occurs later in life (>65 years). We therefore tested single-nucleotide polymorphisms at these loci for association with late-onset AD (LOAD) in a large case-control sample consisting of 3,940 cases and 13,373 controls. Single-marker analysis did not identify any variants that reached genome-wide significance, a result which is supported by other recent genome-wide association studies. However, we did observe a significant association at the MAPT locus using a gene-wide approach (p = 0.009). We also observed suggestive association between AD and the marker rs9468, which defines the H1 haplotype, an extended haplotype that spans the MAPT gene and has previously been implicated in other neurodegenerative disorders including Parkinson's disease, progressive supranuclear palsy, and corticobasal degeneration. In summary common variants at AßPP, PSEN1, and PSEN2 and MAPT are unlikely to make strong contributions to susceptibility for LOAD. However, the gene-wide effect observed at MAPT indicates a possible contribution to disease risk which requires further study.

Genome-wide association study of Alzheimer's disease with psychotic symptoms

Psychotic symptoms occur in ~40% of subjects with Alzheimer's disease (AD) and are associated with more rapid cognitive decline and increased functional deficits. They show heritability up to 61% and have been proposed as a marker for a disease subtype suitable for gene mapping efforts. We undertook a combined analysis of three genome-wide association studies (GWASs) to identify loci that (1) increase susceptibility to an AD and subsequent psychotic symptoms; or (2) modify risk of psychotic symptoms in the presence of neurodegeneration caused by AD. In all, 1299 AD cases with psychosis (AD+P), 735 AD cases without psychosis (AD-P) and 5659 controls were drawn from Genetic and Environmental Risk in AD Consortium 1 (GERAD1), the National Institute on Aging Late-Onset Alzheimer's Disease (NIA-LOAD) family study and the University of Pittsburgh Alzheimer Disease Research Center (ADRC) GWASs. Unobserved genotypes were imputed to provide data on >1.8 million single-nucleotide polymorphisms (SNPs). Analyses in each data set were completed comparing (1) AD+P to AD-P cases, and (2) AD+P cases with controls (GERAD1, ADRC only). Aside from the apolipoprotein E (APOE) locus, the strongest evidence for association was observed in an intergenic region on chromosome 4 (rs753129; 'AD+PvAD-P' P=2.85 × 10(-7); 'AD+PvControls' P=1.11 × 10(-4)). SNPs upstream of SLC2A9 (rs6834555, P=3.0 × 10(-7)) and within VSNL1 (rs4038131, P=5.9 × 10(-7)) showed strongest evidence for association with AD+P when compared with controls. These findings warrant further investigation in larger, appropriately powered samples in which the presence of psychotic symptoms in AD has been well characterized.Molecular Psychiatry advance online publication, 18 October 2011; doi:10.1038/mp.2011.125.

Social effects of collaborative learning in primary schools

There is conflicting evidence on whether collaborative group work leads to improved classroom relations, and if so how. A before and after design was used to measure the impact on work and play relations of a collaborative learning programme involving 575 students 9e12 years old in single- and mixed-age classes across urban and rural schools. Data were also collected on student interactions and teacher ratings of their group-work skills. Analysis of variance revealed significant gains for both types of relation. Multilevel modelling indicated that better work relations were the product of improving group skills, which offset tensions produced by transactive dialogue, and this effect fed through in turn to play relations. Although before intervention rural children were familiar with each other neither this nor age mix affected outcomes. The results suggest the social benefits of collaborative learning are a separate outcome of group work, rather than being either a pre-condition for, or a direct consequence of successful activity, but that initial training in group skills may serve to enhance these benefits.