625 research outputs found

    Polarized Signatures of a Habitable World: Comparing Models of an Exoplanet Earth with Visible and Near-infrared Earthshine Spectra

    Full text link
    In the JWST, Extremely Large Telescopes, and LUVOIR era, we expect to characterize a number of potentially habitable Earth-like exoplanets. However, the characterization of these worlds depends crucially on the accuracy of theoretical models. Validating these models against observations of planets with known properties will be key for the future characterization of terrestrial exoplanets. Due to its sensitivity to the micro- and macro-physical properties of an atmosphere, polarimetry will be an important tool that, in tandem with traditional flux-only observations, will enhance the capabilities of characterizing Earth-like planets. In this paper we benchmark two different polarization-enabled radiative-transfer codes against each other and against unique linear spectropolarimetric observations of the earthshine that cover wavelengths from ∼\sim0.4 to ∼\sim2.3 μ\mum. We find that while the results from the two codes generally agree with each other, there is a phase dependency between the compared models. Additionally, with our current assumptions, the models from both codes underestimate the level of polarization of the earthshine. We also report an interesting discrepancy between our models and the observed 1.27 μ\mum O2O_2 feature in the earthshine, and provide an analysis of potential methods for matching this feature. Our results suggest that only having access to the 1.27 μ\mum O2O_2 feature coupled with a lack of observations of the O2O_2 A and B bands could result in a mischaracterization of an Earth-like atmosphere. Providing these assessments is vital to aid the community in the search for life beyond the solar system.Comment: 24 pages, 18 figure

    The Hispanic Paradox: Race/Ethnicity and Nativity, Immigrant Enclave Residence and Cognitive Impairment Among Older US Adults

    Full text link
    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137472/1/jgs14806.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137472/2/jgs14806_am.pd

    Litter-of-origin trait effects on gilt development

    Get PDF
    The preweaning litter environment of gilts can affect subsequent development. In a recent experiment designed to test the effects of diet on gilt development, litter-of-origin traits including individual birth weights, immunocrits (a measure of colostrum intake), sow parity, number weaned, and individual weaning weights were collected for approximately 1,200 gilts that were progeny of approximately 300 sows. Subsequently, BW, LM area, and backfat were measured at 100 d of age and at 28-d intervals until slaughter (260 d of age). From 160 d of age to slaughter, gilts were observed daily for estrus. At slaughter, the reproductive tract and 1 mammary gland were recovered. The reproductive tract was classified as cyclic or prepubertal; the number of corpora lutea was counted. Uterine horn lengths and ovarian dimensions were measured. Uterus and ovary samples from every 10th gilt were prepared for histological evaluation of uterine gland development and follicle counts, respectively. Mammary gland tissue protein and fat were assayed. Day of the estrous cycle at slaughter was calculated using the first day of the most recent standing estrus (d 0) recorded previous to slaughter. Each gilt development trait was analyzed for association with each litter-of-origin trait, after adjusting for dietary treatment effects. Uterine length, ovarian dimensions, mammary gland protein and fat, and uterine gland development were also adjusted for day of the estrous cycle at slaughter. All litter-of-origin traits were associated (P \u3c 0.05) with growth traits. Top-down (backward elimination) multiple regression analysis indicated that BW and LM accretion in gilts was positively associated with immunocrit (P \u3c 0.01), birth weight (P \u3c 0.01), preweaning growth rate (P \u3c 0.01), and parity (P \u3c 0.01). Backfat accretion was positively associated with preweaning growth rate (P \u3c 0.01), number weaned (P\u3c 0.05), and parity (P \u3c 0.05). Age at puberty was associated with birth weight (positive; P \u3c 0.01) and preweaning growth rate (negative; P \u3c 0.01). Total uterine length was positively associated with only birth weights (P \u3c 0.05). Mammary gland protein was negatively associated with preweaning growth (P\u3c 0.01). Mammary gland fat was positively associated with birth weight and number of piglets weaned (P \u3e 0.05). These results indicate that colostrum consumption, birth weights, preweaning growth rate, number weaned, and parity are associated with gilt development traits during later life

    "They think we're OK and we know we're not". A qualitative study of asylum seekers' access, knowledge and views to health care in the UK

    Get PDF
    <i>Background</i>: The provision of healthcare for asylum seekers is a global issue. Providing appropriate and culturally sensitive services requires us to understand the barriers facing asylum seekers and the facilitators that help them access health care. Here, we report on two linked studies exploring these issues, along with the health care needs and beliefs of asylum seekers living in the UK. <i>Methods</i>: Two qualitative methods were employed: focus groups facilitated by members of the asylum seeking community and interviews, either one-to-one or in a group, conducted through an interpreter. Analysis was facilitated using the Framework method. <i>Results</i>: Most asylum seekers were registered with a GP, facilitated for some by an Asylum Support nurse. Many experienced difficulty getting timely appointments with their doctor, especially for self-limiting symptoms that they felt could become more serious, especially in children. Most were positive about the health care they received, although some commented on the lack of continuity. However, there was surprise and disappointment at the length of waiting times both for hospital appointments and when attending accident and emergency departments. Most had attended a dentist, but usually only when there was a clinical need. The provision of interpreters in primary care was generally good, although there was a tension between interpreters translating verbatim and acting as patient advocates. Access to interpreters in other settings, e.g. in-patient hospital stays, was problematic. Barriers included the cost of over-the-counter medication, e.g. children's paracetamol; knowledge of out-of-hours medical care; and access to specialists in secondary care. Most respondents came from countries with no system of primary medical care, which impacted on their expectations of the UK system. <i>Conclusion</i>: Most asylum seekers were positive about their experiences of health care. However, we have identified issues regarding their understanding of how the UK system works, in particular the role of general practitioners and referral to hospital specialists. The provision of an Asylum Support nurse was clearly a facilitator to accessing primary medical care. Initiatives to increase their awareness and understanding of the UK system would be beneficial. Interpreting services also need to be developed, in particular their role in secondary care and the development of the role of interpreter as patient advocate

    Evolutionary diversity peaks at mid-elevations along an Amazon-to-Andes elevation gradient

    Get PDF
    Elevation gradients present enigmatic diversity patterns, with trends often dependent on the dimension of diversity considered. However, focus is often on patterns of taxonomic diversity and interactions between diversity gradients and evolutionary factors, such as lineage age, are poorly understood. We combine forest census data with a genus level phylogeny representing tree ferns, gymnosperms, angiosperms, and an evolutionary depth of 382 million years, to investigate taxonomic and evolutionary diversity patterns across a long tropical montane forest elevation gradient on the Amazonian flank of the Peruvian Andes. We find that evolutionary diversity peaks at mid-elevations and contrasts with taxonomic richness, which is invariant from low to mid-elevation, but then decreases with elevation. We suggest that this trend interacts with variation in the evolutionary ages of lineages across elevation, with contrasting distribution trends between younger and older lineages. For example, while 53% of young lineages (originated by 10 million years ago) occur only below ∼1,750 m asl, just 13% of old lineages (originated by 110 million years ago) are restricted to below ∼1,750 m asl. Overall our results support an Environmental Crossroads hypothesis, whereby a mid-gradient mingling of distinct floras creates an evolutionary diversity in mid-elevation Andean forests that rivals that of the Amazonian lowlands

    Age at puberty, ovulation rate, and uterine length of developing gilts fed two lysine and three metabolizable energy concentrations from 100 to 260 d of age

    Get PDF
    The objective of this study was to determine the effect of ad libitum feeding diets differing in standard ileal digestible (SID) lysine and ME concentrations that bracket those fed to developing gilts in U.S. commercial settings. Average SID lysine and ME concentrations in diets currently fed to developing gilts were obtained from a poll of the U.S. commercial swine industry. Crossbred Large White × Landrace gilts (n = 1,221), housed in groups, were randomly allotted to 6 corn-soybean diets in a 2 × 3 factorial arrangement formulated to provided 2 SID lysine and 3 ME concentrations. Gilts received grower diets formulated to provide 1.02% (control = survey average) or 0.86% (control minus 15%) SID lysine and 2.94, 3.25, or 3.57 (survey average ME ± 10%) Mcal of ME/kg from 100 d of age until approximately 90 kg BW. Then, gilts were fed finisher diet containing 0.85% (control = survey average) or 0.73% (control minus 15%) SID lysine and 2.94, 3.26, or 3.59 (control ± 10%) Mcal of ME/kg until 260 d of age. Gilts were weighed, and backfat thickness and loin muscle area were recorded at the beginning of the trial and then every 28 d. Starting at 160 d of age, gilts were exposed daily to vasectomized boars and observed for behavioral estrus. At approximately 260 d of age, gilts were slaughtered and their reproductive tract was collected. Each reproductive tract was examined to determine whether the gilt was cyclic, the stage of estrus cycle, ovulation rate, and uterine length. Data were evaluated for normality and analyzed using mixed model methods. Average age at puberty was 193 d of age with a range from 160 to 265 d. When all gilts on trial at 160 d of age were included in the analysis, 91.0% reached puberty as determine by observation of standing estrus. Differences between dietary treatments on age at puberty or measurements of the reproductive tract were not detected. Growth rates to 160 d were not limiting for attainment of puberty in response to daily boar stimulation from 160 d

    A Randomized Controlled Trial of the Effect of Allopurinol on Left Ventricular Mass Index in Hemodialysis Patients

    Get PDF
    Introduction: Increased left ventricular mass index (LVMI) is associated with mortality in end-stage renal disease. LVMI regression may improve outcomes. Allopurinol has reduced LVMI in randomized controlled trials in chronic kidney disease, diabetes, and ischemic heart disease. This study investigated whether allopurinol would regress LVMI in hemodialysis patients. Methods: This was a randomized placebo-controlled double-blind multicenter trial. A total of 80 patients undergoing regular maintenance hemodialysis were recruited from NHS Tayside, NHS Greater Glasgow and Clyde and NHS Ayrshire and Arran in Scotland, UK. Participants were randomly assigned on a 1:1 ratio to 12 months of therapy with allopurinol 300 mg or placebo after each dialysis session. The primary outcome was change in LVMI, as assessed by cardiac magnetic resonance imaging (MRI) at baseline and 12 months. Secondary outcomes were change in BP, flow-mediated dilation (FMD), augmentation indices (AIx), and pulse wave velocity (PWV). Results: A total of 53 patients, with a mean age of 58 years, completed the study and had MRI follow-up data for analysis. Allopurinol did not regress LVMI (change in LVMI: placebo +3.6 ± 10.4 g/m2; allopurinol: +1.6 ± 11 g/m2; P = 0.49). Allopurinol had no demonstrable effect on BP, FMD, AIx, or PWV. Conclusion: Compared with placebo, treatment with allopurinol did not regress LVMI in this trial

    High-yield methods for accurate two-alternative visual psychophysics in head-fixed mice

    Get PDF
    Research in neuroscience increasingly relies on the mouse, a mammalian species that affords unparalleled genetic tractability and brain atlases. Here, we introduce high-yield methods for probing mouse visual decisions. Mice are head-fixed, facilitating repeatable visual stimulation, eye tracking, and brain access. They turn a steering wheel to make two alternative choices, forced or unforced. Learning is rapid thanks to intuitive coupling of stimuli to wheel position. The mouse decisions deliver high-quality psychometric curves for detection and discrimination and conform to the predictions of a simple probabilistic observer model. The task is readily paired with two-photon imaging of cortical activity. Optogenetic inactivation reveals that the task requires mice to use their visual cortex. Mice are motivated to perform the task by fluid reward or optogenetic stimulation of dopamine neurons. This stimulation elicits a larger number of trials and faster learning. These methods provide a platform to accurately probe mouse vision and its neural basis
    • …
    corecore