8,286 research outputs found

    Age and nature of Triassic magmatism in the Netoni Intrusive Complex, West Papua, Indonesia

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    We report field observations together with petrological, geochemical and geochronological data from granitoids of the Netoni Intrusive Complex of West Papua. Until now, our knowledge of the timing of granitic magmatism in this region has been limited to a wide range of ages (241¿6.7 Ma) obtained from K-Ar measurements of hornblende, biotite and plagioclase, primarily from samples of river detritus. We collected in situ samples along several traverses into the intrusive complex to: (1) develop a better understanding of the lithologies within the intrusive complex; and (2) determine the timing of magmatism using U-Pb dating of zircon. We also dated zircons from two river sand samples to identify other potential pulses of magmatism that may have been missed due to a sampling bias. The zircons extracted from the river sands yield age spectra similar to those obtained from the in situ samples. The combined data demonstrate that magmatism in the Netoni Intrusive Complex occurred between 248 Ma and 213 Ma. The petrological and geochemical data indicate that the granitoids were most likely emplaced in an ocean-continent (Andean style) subduction setting. This builds on previous work which suggests that a magmatic belt extended along eastern Gondwana (now New Guinea and eastern Australia) throughout much of the Paleozoic. The volcanic ejecta that were produced along this arc and the subsequent erosion of the mountain chain are a potential source of detritus for Triassic and younger sedimentary rocks in New Guinea, eastern Indonesia and north/northwestern Australia

    Xylem Feeding by Periodical Cicada Nymphs on Pine and Grass Roots, With Novel Suggestions for Pest Control in Conifer Plantations and Orchards

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    Author Institution: Department of Biology, University of ChicagoFirst-instar nymphs of periodical cicadas (Homoptera: Cicadidae: Magicicada) were introduced into a 500-cm2 plot in a relatively pure stand of loblolly pines and into an 1800-cm2 plot on a mowed grassy lawn to determine whether they could feed on pine and grass roots, respectively. Nymphs and their associated roots were excavated within a 2-year period after introduction. Serial root sections from both study sites showed clear evidence of cicada feeding. Cicada salivary sheaths terminated in metaxylem vessels of the grass roots and tracheids of the pine roots. In a pine-hemlock plantation where mature periodical cicada nymphs had emerged, a fiberglass resin cast of the emergence burrow and associated feeding cell was carefully excavated. The feeding rootlet was located and traced to a nearby white pine {Pinus strobus). These observations suggest that the newly hatched nymphs of periodical cicadas can feed on virtually any small rootlet, whether gymnosperm or angiosperm, dicot or monocot. Furthermore, if periodical cicadas become established in a pine plantation, they may be able to feed on pine roots for their entire lives. Two control measures are suggested: 1) prior to a periodical cicada emergence, broad-leaved woody species should be removed from a conifer plantation to prevent successful oviposition by invading cicadas; and 2) in the autumn following an emergence of periodical cicadas in an orchard, the grass cover immediately beneath the canopy of each tree should be killed with an herbicide to starve the young nymphs feeding on grass roots

    Ligand binding dynamics for pre-dimerised G protein-coupled receptor homodimers: Linear models and analytical solutions

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    Evidence suggests that many G protein-coupled receptors (GPCRs) are bound together forming dimers. The implications of dimerisation for cellular signalling outcomes, and ultimately drug discovery and therapeutics, remain unclear. Consideration of ligand binding and signalling via receptor dimers is therefore required as an addition to classical receptor theory, which is largely built on assumptions of monomeric receptors. A key factor in developing theoretical models of dimer signalling is cooperativity across the dimer, whereby binding of a ligand to one protomer affects the binding of a ligand to the other protomer. Here, we present and analyse linear models for one-ligand and two-ligand binding dynamics at homodimerised receptors, as an essential building block in the development of dimerised receptor theory. For systems at equilibrium, we compute analytical solutions for total bound labeled ligand, and derive conditions on the cooperativity factors underwhich multiphasic log-dose-response curves are expected. This could help explain data extracted from pharmacological experiments that does not fit to the standard Hill curves that are often used in this type of analysis. For the time-dependent problems, we also obtain analytical solutions. For the single-ligand case, the construction of the analytical solution is straightforward; it is bi-exponential in time, sharing a similar structure to the well known monomeric competition dynamics of Motulsky-Mahan. We suggest that this model is therefore practically usable by the pharmacologist towards developing insights into the potential dynamics and consequences of dimerised receptors

    To what extent does severity of loneliness vary among different mental health diagnostic groups: A cross-sectional study.

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    Loneliness is a common and debilitating problem in individuals with mental health disorders. However, our knowledge on severity of loneliness in different mental health diagnostic groups and factors associated with loneliness is poor, thus limiting the ability to target and improve loneliness interventions. The current study investigated the association between diagnoses and loneliness and explored whether psychological and social factors were related to loneliness. This study employed a cross-sectional design using data from a completed study which developed a measure of social inclusion. It included 192 participants from secondary, specialist mental health services with a primary diagnosis of psychotic disorders (n = 106), common mental disorders (n = 49), or personality disorders (n = 37). The study explored differences in loneliness between these broad diagnostic groups, and the relationship to loneliness of: affective symptoms, social isolation, perceived discrimination, and internalized stigma. The study adhered to the STROBE checklist for observational research. People with common mental disorders (MD = 3.94, CI = 2.15 to 5.72, P < 0.001) and people with personality disorders (MD = 4.96, CI = 2.88 to 7.05, P < 0.001) reported higher levels of loneliness compared to people with psychosis. These differences remained significant after adjustment for all psychological and social variables. Perceived discrimination and internalized stigma were also independently associated with loneliness and substantially contributed to a final explanatory model. The severity of loneliness varies between different mental health diagnostic groups. Both people with common mental disorders and personality disorders reported higher levels of loneliness than people with psychosis. Addressing perceived mental health discrimination and stigma may help to reduce loneliness

    Lithospheric-scale structures in New Guinea and their control on the location of gold and copper deposits

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    The locations of major gold and copper deposits on the island of New Guinea are considered by many to be controlled by a series of transfer faults that strike N–S to NE–SW, perpendicular to the long axis of the island. The premise is that these faults dilate perpendicular to the regional stress field, forming conduits for metalliferous gases and fluids to drop out of solution. However, the data on which this idea was first proposed were often not presented or, when the data were presented, were of poor quality or low resolution. We therefore present a review of the existing structural interpretations and compare these with several recently published geophysical data sets to determine if the mineralization controlling transfer faults could be observed. These data were used to produce a new lineament map of New Guinea. A comparison of the lineaments with the location of major gold and copper deposits indicates there is a link between the arc-normal structures and mineralization. However, it is only those deposits that are less than 4.5 million years old that could be associated with these structures. Gravity and seismic tomography data indicate that some of these structures could penetrate deep levels of the lithosphere, providing some support to the earlier idea that the arc-normal structures act as conduits for the younger mineral deposits of New Guinea. The gravity data can also be used to infer the location of igneous intrusions at depth, which could have brought metal-bearing fluids and gases closer to the Earth's surface. These regions might be of interest for future exploration campaigns, particularly those areas that are crosscut by deep, vertical faults. However, new exploration models are needed to explain the location of the deposits that are older than 5 Ma

    Validity, reliability, acceptability, and utility of the Social Inclusion Questionnaire User Experience (SInQUE): a clinical tool to facilitate social inclusion amongst people with severe mental health problems.

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    BACKGROUND: Individuals with severe mental health problems are at risk of social exclusion, which may complicate their recovery. Mental health and social care staff have, until now, had no valid or reliable way of assessing their clients' social inclusion. The Social Inclusion Questionnaire User Experience (SInQUE) was developed to address this. It assesses five domains: social integration; productivity; consumption; access to services; and political engagement, in the year prior to first psychiatric admission (T1) and the year prior to interview (T2) from which a total score at each time point can be calculated. AIMS: To establish the validity, reliability, and acceptability of the SInQUE in individuals with a broad range of psychiatric diagnoses receiving care from community mental health services and its utility for mental health staff. METHOD: Participants were 192 mental health service users with psychosis, personality disorder, or common mental disorder (e.g., depression, anxiety) who completed the SInQUE alongside other validated outcome measures. Test-retest reliability was assessed in a sub-sample of 30 participants and inter-rater reliability was assessed in 11 participants. SInQUE ratings of 28 participants were compared with those of a sibling with no experience of mental illness to account for shared socio-cultural factors. Acceptability and utility of the tool were assessed using completion rates and focus groups with staff. RESULTS: The SInQUE demonstrated acceptable convergent validity. The total score and the Social Integration domain score were strongly correlated with quality of life, both in the full sample and in the three diagnostic groups. Discriminant validity and test-retest reliability were established across all domains, although the test-retest reliability on scores for the Service Access and Political Engagement domains prior to first admission to hospital (T1) was lower than other domains. Inter-rater reliability was excellent for all domains at T1 and T2. CONCLUSIONS: The component of the SInQUE that assesses current social inclusion has good psychometric properties and can be recommended for use by mental health staff
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