718 research outputs found

    Evidence for suppressed mid-Holocene northeastern Australian monsoon variability from coral luminescence

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    Summer monsoon rainfall in northeastern (NE) Australia exhibits substantial interannual variability resulting in highly variable river flows. The occurrence and magnitude of these seasonal river flows are reliably recorded in modern inshore corals as luminescent lines. Here we present reconstructed annual river flows for two ~120 year mid-Holocene windows based on luminescence measurements from five cores obtained from three separate coral colonies. We were able to cross-date the luminescence signatures in four cores from two of the colonies, providing confidence in the derived reconstruction. Present-day NE Australian rainfall and river flow are sensitive to El Niño–Southern Oscillation (ENSO) variability, with La Niña (El Niño) events typically associated with wetter (drier) monsoon seasons. Thus, our replicated and annually resolved coral records provide valuable insights into the northern Australian summer monsoon and ENSO variability at a key period (6 ka) when greenhouse gas levels and ice sheet cover were comparable to the preindustrial period but orbital forcing was different. Average modern and mid-Holocene growth characteristics were very similar, suggesting that sea surface temperatures off NE Australia at 6 kyr were also close to present values. The reconstructed river flow record suggests, however, that the mid-Holocene Australian summer monsoon was weaker, less variable from year to year (possibly indicative of reduced ENSO variability), and characterized by more within-season flood pulses than present. In contrast to today, the delivery of moisture appears to have been dominated by eastward propagating convective coupled waves associated with the Madden-Julian Oscillation

    History of Psychology

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    Openly licensed anthology focused on the theme of the History of Psychology. Contains: The Mind and the Brain by Alfred Binet; Dream Psychology: Psychoanalysis for Beginners by Sigmund Freud; The Principles of Psychology, Volume 1 (of 2) by William James; The Principles of Psychology, Volume 2 (of 2) by William James; Collected Papers on Analytical Psychology by C. G. Jung; Memoirs of Extraordinary Popular Delusions and the Madness of Crowds by Charles Mackay; The Psychology of Arithmetic by Edward L. Thorndike

    Mild parenchymal lung disease and/or low diffusion capacity impacts survival and treatment response in patients diagnosed with idiopathic pulmonary arterial hypertension

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    There are limited published data defining survival and treatment response in patients with mild lung disease and/or reduced gas transfer who fulfil diagnostic criteria for idiopathic pulmonary arterial hypertension (IPAH). Patients diagnosed with IPAH between 2001–19 were identified in the ASPIRE registry. Using pre-specified criteria based on CT imaging and spirometry, patients with a diagnosis of IPAH and no lung disease were termed IPAHno-LD (n=303), and those with minor-mild emphysema or fibrosis were described as IPAHmild-LD (n=190). Survival was significantly better in IPAHno-LD than in IPAHmild-LD (1 and 5-year survival 95% and 70% versus 78% and 22% respectively, p<0.0001). In the combined group of IPAHno-LD and IPAHmild-LD, independent predictors of higher mortality were increasing age, lower DLCO, lower exercise capacity and a diagnosis of IPAHmild-LD (p all <0.05). Exercise capacity and quality of life improved (p both <0.0001) following treatment in patients with IPAHno-LD but not IPAHmild-LD. A proportion of patients with IPAHno-LD had a DLCO <45%; these patients had poorer survival than patients with DLCO ≥45% although demonstrated improved exercise capacity following treatment. The presence of even mild parenchymal lung disease in patients who would be classified as IPAH according to current recommendations has a significant adverse effect on outcomes. This phenotype can be identified using lung function testing and clinical CT reports. Patients with IPAH, no lung disease and severely reduced DLCO may represent a further distinct phenotype. These data suggest that RCTs of targeted therapies in patients with these phenotypes are required

    Neutron scattering and molecular correlations in a supercooled liquid

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    We show that the intermediate scattering function Sn(q,t)S_n(q,t) for neutron scattering (ns) can be expanded naturely with respect to a set of molecular correlation functions that give a complete description of the translational and orientational two-point correlations in the liquid. The general properties of this expansion are discussed with special focus on the qq-dependence and hints for a (partial) determination of the molecular correlation functions from neutron scattering results are given. The resulting representation of the static structure factor Sn(q)S_n(q) is studied in detail for a model system using data from a molecular dynamics simulation of a supercooled liquid of rigid diatomic molecules. The comparison between the exact result for Sn(q)S_n(q) and different approximations that result from a truncation of the series representation demonstrates its good convergence for the given model system. On the other hand it shows explicitly that the coupling between translational (TDOF) and orientational degrees of freedom (ODOF) of each molecule and rotational motion of different molecules can not be neglected in the supercooled regime.Further we report the existence of a prepeak in the ns-static structure factor of the examined fragile glassformer, demonstrating that prepeaks can occur even in the most simple molecular liquids. Besides examining the dependence of the prepeak on the scattering length and the temperature we use the expansion of Sn(q)S_n(q) into molecular correlation functions to point out intermediate range orientational order as its principle origin.Comment: 13 pages, 7 figure

    Task specific influences of Parkinson’s disease on the striato-thalamo-cortical and cerebello-thalamo-cortical motor circuitries

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    The motor deficits in Parkinson’s disease (PD) have been primarily associated with internally guided (IG), but not externally guided (EG), tasks. This study investigated the functional mechanisms underlying this phenomenon using genetically-matched twins. Functional magnetic resonance images were obtained from a monozygotic twin pair discordant for clinical PD. Single-photon emission computed tomography neuroimaging using [123I](−)-2-β-carboxymethoxy-3-β-(4-iodophenyl)tropane confirmed their disease-discordant status by demonstrating a severe loss of transporter binding in the PD-twin, whereas the non-PD-twin was normal. Six runs of fMRI data were acquired from each twin performing EG and IG right-hand finger sequential tasks. The percentage of voxels activated in each of several regions of interest (ROI) was calculated. Multiple analysis of variance was used to compare each twin’s activity in ROIs constituting the striato-thalamo-cortical motor circuits [basal ganglia (BG)-cortical circuitry, but including the globus pallidus/putamen, thalamus, supplementary motor area, and primary motor cortex] and cerebello-thalamo-cortical circuits (referred to as the cerebellar–cortical circuitry, including the cerebellum, thalamus, somatosensory cortex, and lateral premotor cortex). During the EG task, there were no significant differences between the twins in bilateral BG-cortical pathways, either basally or after levodopa, whereas the PD-twin had relatively increased activity in the cerebellar-cortical pathways basally that was normalized by levodopa. During the IG task, the PD-twin had less activation than the non-PD-twin in ROIs of the bilateral BG-cortical and cerebellar-cortical pathways. Levodopa normalized the hypoactivation in the contralateral BG-cortical pathway, but “over-corrected” the activation in the ipsilateral BG-cortical and bilateral cerebellar-cortical pathways. In this first fMRI study of twins discordant for PD, the data support the hypothesis that BG-cortical and cerebellar-cortical pathways are task-specifically influenced by PD. The levodopa-induced “over-activation” of BG-cortical and cerebellar-cortical pathways, and its relevance to both compensatory changes in PD and the long-term effects of levodopa in PD, merit further exploration

    Revisiting Generalized Chaplygin Gas as a Unified Dark Matter and Dark Energy Model

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    In this paper, we revisit generalized Chaplygin gas (GCG) model as a unified dark matter and dark energy model. The energy density of GCG model is given as ρGCG/ρGCG0=[Bs+(1Bs)a3(1+α)]1/(1+α)\rho_{GCG}/\rho_{GCG0}=[B_{s}+(1-B_{s})a^{-3(1+\alpha)}]^{1/(1+\alpha)}, where α\alpha and BsB_s are two model parameters which will be constrained by type Ia supernova as standard candles, baryon acoustic oscillation as standard rulers and the seventh year full WMAP data points. In this paper, we will not separate GCG into dark matter and dark energy parts any more as adopted in the literatures. By using Markov Chain Monte Carlo method, we find the result: α=0.001260.001260.00126+0.000970+0.00268\alpha=0.00126_{- 0.00126- 0.00126}^{+ 0.000970+ 0.00268} and Bs=0.7750.01610.0338+0.0161+0.0307B_s= 0.775_{- 0.0161- 0.0338}^{+ 0.0161+ 0.0307}.Comment: 6 pages, 4 figure

    Knowledge, interest, and anticipated barriers of pre-exposure prophylaxis uptake and adherence among gay, bisexual, and men who have sex with men who are incarcerated

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    Criminal justice (CJ) settings disproportionately include populations at high risk for acquiring HIV, and CJ-involved individuals are often at the intersection of multiple overlapping risk factors. However, few studies have examined attitudes about pre-exposure prophylaxis (PrEP) among incarcerated men who have sex with men (MSM). This study explored interest in, knowledge of, and barriers to PrEP uptake among gay, bisexual, and other men who have sex with men at the Rhode Island Department of Corrections. Using semi-structured interviews, 26 MSM were interviewed about PrEP knowledge, interest, timing preferences for provision (e.g. before or after release), and barriers to uptake and adherence during community re-entry. Interviews were coded and analyzed using a general inductive approach. Participants demonstrated low initial knowledge of PrEP but high interest after being told more about it. Participants self-identified risk factors for HIV acquisition, including condom-less sex and substance use. In addition, participants preferred provision of PrEP prior to release. Post-release barriers to PrEP uptake and adherence included 1) concerns about costs of PrEP medications; 2) anticipated partner or family disapproval; 3) lack of access to transportation; 4) unstable housing; 5) compounding impacts of multiple hardships leading to a de-prioritization of PrEP and 6) fears of future re-incarceration. These results point to the need for future PrEP interventions among incarcerated populations that address incarceration and PrEP related barriers during community re-entry via wraparound services that address PrEP and incarceration-related barriers

    Coalescence of nanoscale metal clusters: Molecular-dynamics study

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    We study the coalescence of nanoscale metal clusters in an inert-gas atmosphere using constant-energy molecular dynamics. The coalescence proceeds via atomic diffusion with the release of surface energy raising the temperature. If the temperature exceeds the melting point of the coalesced cluster, a molten droplet forms. If the temperature falls between the melting point of the larger cluster and those of the smaller clusters, a metastable molten droplet forms and freezes.Comment: 5 figure
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