40 research outputs found

    Analysis of Spectral Mapping Techniques for the OSIRIS-REx Project

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    Tutoring Tutors on Tutoring

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    Identification of a 4.3 billion year old asteroid family and planetesimal population in the Inner Main Belt

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    After performing a reassessment of the known dynamical asteroid families in the inner main belt, we report a newly discovered ancient asteroid family with an estimated age of 4.3±1.74.3\pm1.7 billion years. Additionally, we report the most comprehensive list of planetesimals, which are asteroids that survived since the planet forming days of the solar system.Comment: 21 pages, 13 figure

    Age of Insomnia Onset Correlates with a Reversal of Default Mode Network and Supplementary Motor Cortex Connectivity

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    Insomnia might occur as result of increased cognitive and physiological arousal caused by acute or long acting stressors and associated cognitive rumination. This might lead to alterations in brain connectivity patterns as those captured by functional connectivity fMRI analysis, leading to potential insight about primary insomnia (PI) pathophysiology as well as the impact of long-term exposure to sleep deprivation. We investigated changes of voxel-wise connectivity patterns in a sample of 17 drug-naïve PI patients and 17 age-gender matched healthy controls, as well as the relationship between brain connectivity and age of onset, illness duration, and severity. Results showed a significant increase in resting-state functional connectivity of the bilateral visual cortex in PI patients, associated with decreased connectivity between the visual cortex and bilateral temporal pole. Regression with clinical scores originally unveiled a pattern of increased local connectivity as measured by intrinsic connectivity contrast (ICC), specifically resembling the default mode network (DMN). Additionally, age of onset was found to be correlated with the connectivity of supplementary motor area (SMA), and the strength of DMN←→SMA connectivity was significantly correlated with both age of onset (R2 = 41%) and disease duration (R2 = 21%). Chronic sleep deprivation, but most importantly early insomnia onset, seems to have a significant disruptive effect over the physiological negative correlation between DMN and SMA, a well-known fMRI marker of attention performance in humans. This suggests the need for more in-depth investigations on the prevention and treatment of connectivity changes and associated cognitive and psychological deficits in PI patients

    Charting the Galactic acceleration field II. A global mass model of the Milky Way from the STREAMFINDER Atlas of Stellar Streams detected in Gaia DR3

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    We present an atlas and follow-up spectroscopic observations of 87 thin stream-like structures detected with the STREAMFINDER algorithm in Gaia DR3, of which 29 are new discoveries. Here we focus on using these streams to refine mass models of the Galaxy. Fits with a double power law halo with the outer power law slope set to βh=3-\beta_h=3 yield an inner power law slope γh=0.970.21+0.17-\gamma_h=0.97^{+0.17}_{-0.21}, a scale radius of r0,h=14.71.0+4.7r_{0, h}=14.7^{+4.7}_{-1.0} kpc, a halo density flattening qm,h=0.75±0.03q_{m, h}=0.75\pm0.03, and a local dark matter density of ρh,=0.0114±0.0007Mpc3\rho_{h, \odot}=0.0114\pm0.0007 {\rm M_\odot pc^{-3}}. Freeing β\beta yields β=2.530.16+0.42\beta=2.53^{+0.42}_{-0.16}, but this value is heavily influenced by our chosen virial mass limit. The stellar disks are found to have a combined mass of 4.200.53+0.44×1010M4.20^{+0.44}_{-0.53}\times10^{10} {\rm M_\odot}, with the thick disk contributing 12.4±0.712.4\pm0.7\% to the local stellar surface density. The scale length of the thin and thick disks are 2.170.08+0.182.17^{+0.18}_{-0.08} kpc and 1.620.13+0.721.62^{+0.72}_{-0.13} kpc, respectively, while their scale heights are 0.3470.010+0.0070.347^{+0.007}_{-0.010} kpc and 0.860.02+0.030.86^{+0.03}_{-0.02} kpc, respectively. The virial mass of the favored model is M200=1.090.14+0.19×1012MM_{200}=1.09^{+0.19}_{-0.14}\times 10^{12} {\rm M_\odot}, while the mass inside of 50 kpc is MR<50=0.46±0.03×1012MM_{R<50}=0.46\pm0.03\times 10^{12} {\rm M_\odot}. We introduce the Large Magellanic Cloud (LMC) into the derived potential models, and fit the "Orphan" stream therein, finding a mass for the LMC that is consistent with recent estimates. Some highlights of the atlas include the nearby trailing arm of ω\omega-Cen, and a nearby very metal-poor stream that was once a satellite of the Sagittarius dwarf galaxy. Finally, we unambiguously detect a hot component around the GD-1 stream, consistent with it having been tidally pre-processed within its own DM subhalo.Comment: 43 pages, 26 figures, submitted to Ap

    An assessment of prevalence of Type 1 CFI rare variants in European AMD, and why lack of broader genetic data hinders development of new treatments and healthcare access

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    PurposeAdvanced age-related macular degeneration (AAMD) risk is associated with rare complement Factor I (FI) genetic variants associated with low FI protein levels (termed ‘Type 1’), but it is unclear how variant prevalences differ between AMD patients from different ethnicities.MethodsCollective prevalence of Type 1 CFI rare variant genotypes were examined in four European AAMD datasets. Collective minor allele frequencies (MAFs) were sourced from the natural history study SCOPE, the UK Biobank, the International AMD Genomics Consortium (IAMDGC), and the Finnish Biobank Cooperative (FINBB), and compared to paired control MAFs or background population prevalence rates from the Genome Aggregation Database (gnomAD). Due to a lack of available genetic data in non-European AAMD, power calculations were undertaken to estimate the AAMD population sizes required to identify statistically significant association between Type 1 CFI rare variants and disease risk in different ethnicities, using gnomAD populations as controls.ResultsType 1 CFI rare variants were enriched in all European AAMD cohorts, with odds ratios (ORs) ranging between 3.1 and 7.8, and a greater enrichment was observed in dry AMD from FINBB (OR 8.9, 95% CI 1.49–53.31). The lack of available non-European AAMD datasets prevented us exploring this relationship more globally, however a statistical association may be detectable by future sequencing studies that sample approximately 2,000 AAMD individuals from Ashkenazi Jewish and Latino/Admixed American ethnicities.ConclusionsThe relationship between Type 1 CFI rare variants increasing odds of AAMD are well established in Europeans, however the lack of broader genetic data in AAMD has adverse implications for clinical development and future commercialisation strategies of targeted FI therapies in AAMD. These findings emphasise the importance of generating more diverse genetic data in AAMD to improve equity of access to new treatments and address the bias in health care.</p

    Controversies surrounding vitamin D: Focus on supplementation and cancer

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    There has recently been a huge number of publications concerning various aspects of vitamin D, from the physiological to therapeutic fields. However, as a consequence of this very fast-growing scientific area, some issues still remain surrounded by uncertainties, without a final agreement having been reached. Examples include the definitions of vitamin D sufficiency and insufficiency, (i.e., 20 vs. 30 ng/mL), the relationship between 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone, (i.e., linear vs. no linear), the referent to consider, (i.e., total vs. free determination), the utility of screening versus universal supplementation, and so on. In this review, the issues related to vitamin D supplementation in subjects with documented hypovitaminosis, and the role of vitamin D in cancer will be concisely considered. Daily, weekly, or monthly administration of cholecalciferol generally leads to essentially similar results in terms of an increase in 25(OH)D serum levels. However, we should also consider possible differences related to a number of variables, (i.e., efficiency of intestinal absorption, binding to vitamin D binding protein, and so on). Thus, adherence to therapy may be more important than the dose regimen chosen in order to allow long-term compliance in a sometimes very old population already swamped by many drugs. It is difficult to draw firm conclusions at present regarding the relationship between cancer and vitamin D. In vitro and preclinical studies seem to have been more convincing than clinical investigations. Positive results in human studies have been mainly derived from post-hoc analyses, secondary end-points or meta-analyses, with the last showing not a decrease in cancer incidence but rather in mortality. We must therefore proceed with a word of caution. Until it has been clearly demonstrated that there is a causal relationship, these positive “non-primary, end-point results” should be considered as a background for generating new hypotheses for future investigations

    A green deep eutectic solvent dispersive liquid-liquid micro-extraction (DES-DLLME) for the UHPLC-PDA determination of oxyprenylated phenylpropanoids in olive, soy, peanuts, corn, and sunflower oil

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    A green dispersive liquid-liquid microextraction (DLLME) using deep eutectic solvent (DES) as the extracting solvent has been developed and applied for the simultaneous quantification of ferulic acid, umbelliferone, boropinic acid, 7-isopentenyloxycoumarin, 4′-geranyloxyferulic acid (GOFA), and auraptene in some vegetable oils using ultra high performance liquid chromatography (UHPLC) with photodiode array detection (PDA). All parameters in the extraction step, including selection and loading of both extracting and dispersing solvents, amount of both extractant and disperser solvent were investigated and optimized. PhAA/TMG DES achieved higher recovery and enrichment factor compared to other DESs. The validated method showed good linearity with correlation coefficients, r2 &gt; 0.9990 for all the analytes. Furthermore, this is the first time that eco- friendly solvents are used for the extraction of oxyprenylated phenylpropanoids and the corresponding extract analyzed with ultra high performance liquid chromatography with photodiode array detection
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