The petrogenesis of pyroxenites containing octahedral graphite and associated mafic and ultramafic rocks of the Beni Bousera peridotite massif, N. Morocco

The Beni Bousera peridotite massif, N. Morocco, contains pyroxenite layers of varied mineralogy, including graphitic garnet clinopyroxenite ( GGP ) layers. The graphite in these rocks occurs as octahedral multi-crystalline aggregates and other forms of cubic symmetry. Scanning electron microscopy and X-ray diffraction studies indicate that the graphite aggregates represent graphitized diamonds. Minor Na in coexisting garnets confirm ran origin in the diamond stability field. However, other mineral chemical data from the peridotites and pyroxenites indicate major sub-solidus re-equilibration of the silicate assemblages. Major and trace element analyses indicate the peridotites are residues of partial melting (5-30 %) in the spinel and possibly garnet stability fields. Some peridotites have suffered Fe and/or LREE enrichment. The pyroxenite suite crystallized as veins/dikes in the peridotites and show fractionation trends controlled by OPX, CPX, garnet and possibly spinel. The LREE depleted nature of the pyroxenite suite, combined with their highly variable incompatible element contents which do not correlate with fractionation indices such as Mg No., preclude their derivation from the host peridotites and require a chemically heterogeneous source/sources. Positive and negative Eu anomalies in the pyroxenites suggest their derivation from a low pressure precursor. Sr, Pb and Nd isotope analyses of the peridotites reveal large magnitude, small scale ( sub-km ) heterogeneities. Pyroxenites show even greater isotopic diversity and a decoupling of trace element-isotope systematics which indicate a recent melting event Sr, Pb and Nd isotopes indicate both peridotites and pyroxenites have experienced complex, long term evolution. The extreme isotopic diversity of the pyroxenites, with Pb isotope compositions that plot both to the left and right of the geochron, with high Δ7/4 and Δ8/4 values, are consistent with their derivation as melts of subducted oceanic crust plus less than 1% sediment, over 1 Ga ago. This interpretation is supported by pronounced oxygen isotope variability ( 8 ^ 18 0 = +4.9 to +9.3 %o ) suggesting the oceanic crustal source/s were hydrothermally altered before subduction. Hydrothermal alteration augmented Sr and Pb isotopicheterogeneity in the pyroxenites. If the isotopically light graphite in the GGP ( 8^13 C = -17 to -27 %o ) represents the carbon isotopic composition of the precursor diamonds, the original diamonds may have formed from subducted crustal ( kerogenous?) carbon. A model is proposed invoking subduction of hydrothermally altered oceanic crust and lithosphere, together with minor amounts of sediment (< 1 % ) into the asthenosphere over 1 Ga ago. The subducted oceanic slab descended to the 670km seismic discontinuity and "ponded” to form a megalith. Thermal equilibration of this megalith induced diapirism into the asthenosphere. Melting during ascent may have formed the pyroxenite layers and refertilized some of the peridotites. Asthenospheric upwelling during a major Neogene extensional event initiated emplacement of pyroxenite veined peridotitic mantle into the N. African, crust. Recent, small degree partial melting during ascent into the crust decoupled parent-daughter isotope systematics in the pyroxenites and peridotites. Graphitization of diamond in the GGP may also have occurred at this time. Pyroxenites containing graphitized diamonds in an orogenic peridotite massif provide evidence in support of a non-volcanic source for diamonds of unexplained provenance which occur in, or close to, major tectonic collision zone

Battlefield Casualty: The Archaeology of a Captured Gun

Many artefacts in museums lack adequate information about the context from which they were collected. Not surprisingly, this often applies to artefacts recovered from battlefields, where chaotic conditions can result in uncertainty about their origins. This paper examines the case of a Second World War German 88 mm gun preserved in an Australian museum. The museum had little contextual information for this weapon, except that the Australian Army captured it in North Africa in 1942, probably after the Second Battle of El Alamein. However, an archaeological analysis of the gun, particularly of damage incurred during battle, can link it to photographs taken after the battle and re-establish its historical context and the circumstances of its acquisition. In this way, a museum artefact can become more than a mere exhibit: it can be made to document its own past

British Thoracic Society quality standards for the investigation and management of pulmonary nodules

IntroductionThe purpose of the quality standards document is to provide healthcare professionals, commissioners, service providers and patients with a guide to standards of care that should be met for the investigation and management of pulmonary nodules in the UK, together with measurable markers of good practice.MethodsDevelopment of British Thoracic Society (BTS) Quality Standards follows the BTS process of quality standard production based on the National Institute for Health and Care Excellence process manual for the development of quality standards.Results7 quality statements have been developed, each describing a key marker of high-quality, cost-effective care for the investigation and management of pulmonary nodules, and each statement is supported by quality measures that aim to improve the structure, process and outcomes of healthcare.DiscussionBTS Quality Standards for the investigation and management of pulmonary nodules form a key part of the range of supporting materials that the Society produces to assist in the dissemination and implementation of guideline recommendations.</jats:sec

Early Eocene Arctic volcanism from carbonate-metasomatized mantle

Melilitite, nephelinite, basanite, and alkali basalt, along with phonolite differentiates, form the Freemans Cove Complex (FCC) in the south-eastern extremity of Bathurst Island (Nunavut, Canada). New 40Ar/39Ar chronology indicates their emplacement between ~ 56 and ~ 54 million years ago within a localized extensional structure. Melilitites and nephelinites, along with phonolite differentiates, likely relate to the beginning and end phases of extension, whereas alkali basalts were emplaced during a main extensional episode at ~ 55 Ma. The melilitites, nephelinites, and alkali basalts show no strong evidence for significant assimilation of crust, in contrast to some phonolites. Partial melting occurred within both the garnet- and spinel-facies mantle and sampled sources with He, O, Nd, Hf, and Os isotope characteristics indicative of peridotite with two distinct components. The first, expressed in higher degree partial melts, represents a relatively depleted component (“A”; 3He/4He ~ 8 RA, εNdi ~ + 3 εHfi ~ + 7, γOsi ~ 0). The second was an enriched component (“B” 3He/4He + 70) sampled by the lowest degree partial melts and represents carbonate-metasomatized peridotite. Magmatism in the FCC shows that rifting extended from the Labrador Sea to Bathurst Island and reached a zenith at ~ 55 Ma, during the Eurekan orogeny. The incompatible trace-element abundances and isotopic signatures of FCC rocks indicate melt generation occurred at the base of relatively thin lithosphere at the margin of a thick craton, with no mantle plume influence. FCC melt compositions are distinct from other continental rift magmatic provinces worldwide, and their metasomatized mantle source was plausibly formed synchronously with emplacement of Cretaceous kimberlites. The FCC illustrates that the range of isotopic compositions preserved in continental rift magmas are likely to be dominated by temporal changes in the extent of partial melting, as well as by the timing and degree of metasomatism recorded in the underlying continental lithosphere

Mental health of people with multiple sclerosis during the COVID-19 outbreak: A prospective cohort and cross-sectional case–control study of the UK MS Register

Background: People with MS (pwMS) have had higher rates of anxiety and depression than the general population before the COVID-19 pandemic, placing them at higher risk of experiencing poor psychological wellbeing during the pandemic.Objective: To assess mental health and its social/lifestyle determinants in pwMS during the first wave of the outbreak in the UK.Methods: This is a community-based, prospective longitudinal cohort and cross-sectional case-control online questionnaire study. It includes 2,010 pwMS from the UK MS Register and 380 people without MS.Results: The Hospital Anxiety and Depression Scale scores of pwMS for anxiety and depression during the outbreak did not change from the previous year. PwMS were more likely to have anxiety (using General Anxiety Disorder-7) and/or depression (using Patient Health Questionnaire-9) than controls during the outbreak (OR:2.14[95%CI:1.58-2.91]). PwMS felt lonelier (OR:1.37[95%CI:1.04-1.80]), reported worse social support (OR:1.90[95%CI:1.18-3.07]) and reported worsened exercise habits (OR:1.65[95%CI:1.18-2.32]) during the outbreak than controls.Conclusion: Early in the pandemic, pwMS remained at higher risk of experiencing anxiety and depression than the general population. It is important that multidisciplinary teams improve their support for the wellbeing of pwMS, who are vulnerable to the negative effects of the pandemic on their lifestyle and social support

Arterial spin labelling reveals an abnormal cerebral perfusion pattern in Parkinson's disease

There is a need for objective imaging markers of Parkinson's disease status and progression. Positron emission tomography and single photon emission computed tomography studies have suggested patterns of abnormal cerebral perfusion in Parkinson's disease as potential functional biomarkers. This study aimed to identify an arterial spin labelling magnetic resonance-derived perfusion network as an accessible, non-invasive alternative. We used pseudo-continuous arterial spin labelling to measure cerebral grey matter perfusion in 61 subjects with Parkinson's disease with a range of motor and cognitive impairment, including patients with dementia and 29 age- and sex-matched controls. Principal component analysis was used to derive a Parkinson's disease-related perfusion network via logistic regression. Region of interest analysis of absolute perfusion values revealed that the Parkinson's disease pattern was characterized by decreased perfusion in posterior parieto-occipital cortex, precuneus and cuneus, and middle frontal gyri compared with healthy controls. Perfusion was preserved in globus pallidus, putamen, anterior cingulate and post- and pre-central gyri. Both motor and cognitive statuses were significant factors related to network score. A network approach, supported by arterial spin labelling-derived absolute perfusion values may provide a readily accessible neuroimaging method to characterize and track progression of both motor and cognitive status in Parkinson's diseas

Analysis of the transcriptome of the protozoan Theileria parva using MPSS reveals that the majority of genes are transcriptionally active in the schizont stage

Massively parallel signature sequencing (MPSS) was used to analyze the transcriptome of the intracellular protozoan Theileria parva. In total 1 095 000, 20 bp sequences representing 4371 different signatures were generated from T.parva schizonts. Reproducible signatures were identified within 73% of potentially detectable predicted genes and 83% had signatures in at least one MPSS cycle. A predicted leader peptide was detected on 405 expressed genes. The quantitative range of signatures was 4–52 256 transcripts per million (t.p.m.). Rare transcripts (<50 t.p.m.) were detected from 36% of genes. Sequence signatures approximated a lognormal distribution, as in microarray. Transcripts were widely distributed throughout the genome, although only 47% of 138 telomere-associated open reading frames exhibited signatures. Antisense signatures comprised 13.8% of the total, comparable with Plasmodium. Eighty five predicted genes with antisense signatures lacked a sense signature. Antisense transcripts were independently amplified from schizont cDNA and verified by sequencing. The MPSS transcripts per million for seven genes encoding schizont antigens recognized by bovine CD8 T cells varied 1000-fold. There was concordance between transcription and protein expression for heat shock proteins that were very highly expressed according to MPSS and proteomics. The data suggests a low level of baseline transcription from the majority of protein-coding genes

Cohort profile : the Scottish Diabetes Research Network national diabetes cohort - a population-based cohort of people with diabetes in Scotland

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Suicide prevention in primary care: General practitioners' views on service availability

BackgroundPrimary care may be a key setting for suicide prevention. However, comparatively little is known about the services available in primary care for suicide prevention. The aims of the current study were to describe services available in general practices for the management of suicidal patients and to examine GPs views on these services. We carried out a questionnaire and interview study in the North West of England. We collected data on GPs views of suicide prevention generally as well as local mental health service provision.FindingsDuring the study period (2003-2005) we used the National Confidential Inquiry Suicide database to identify 286 general practitioners (GPs) who had registered patients who had died by suicide. Data were collected from GPs and practice managers in 167 practices. Responses suggested that there was greater availability of services and training for general mental health issues than for suicide prevention specifically. The three key themes which emerged from GP interviews were: barriers accessing primary or secondary mental health services; obstacles faced when referring a patient to mental health services; managing change within mental health care servicesConclusionsHealth professionals have an important role to play in preventing suicide. However, GPs expressed concerns about the quality of primary care mental health service provision and difficulties with access to secondary mental health services. Addressing these issues could facilitate future suicide prevention in primary care