127 research outputs found
The total rest-frame UV luminosity function from : A simultaneous study of AGN and galaxies from
We present measurements of the rest-frame ultraviolet luminosity function (UV
LF) at redshifts , and , using 96894, 38655 and 7571 sources
respectively to map the transition between AGN and galaxy-dominated ultraviolet
emission shortly after the epoch of reionization. Sources are selected using a
comprehensive photometric redshift approach, using \ds\, of deep
extragalactic legacy fields covered by both HSC and VISTA. The use of template
fitting spanning a wavelength range of achieves
per cent completeness, much higher than classical colour-colour
cut methodology. The measured LF encompasses at
. This is further extended to using
complementary results from other studies, allowing for the simultaneous fitting
of the combined AGN and galaxy LF. We find that there are fewer UV luminous
galaxies () at than , indicative of an onset
of widespread quenching alongside dust obscuration, and that the evolution of
the AGN LF is much more rapid than the galaxy LF, with their number density
rising by around 2 orders of magnitude from . We also find that it
remains difficult to determine if a double power law (DPL) functional form is
preferred over the Schechter function to describe the galaxy UV LF with
photometric data alone. Estimating the Hydrogen ionizing photon budget from our
UV LFs, we find that AGN can contribute to, but cannot solely maintain, the
reionization of the Universe at . However, the rapidly evolving AGN LF
strongly disfavours a significant contribution within the EoR.Comment: 20 pages, 5 Tables, 12 Figures, Submitted to MNRA
The bright end of the galaxy luminosity function at from the VISTA VIDEO survey
We have conducted a search for Lyman break galaxies over 8.2
square degrees of near-infrared imaging from the VISTA Deep Extragalactic
Observations (VIDEO) survey in the XMM-Newton - Large Scale Structure (XMM-LSS)
and the Extended Chandra Deep Field South (ECDF-S) fields. Candidate galaxies
were selected from a full photometric redshift analysis down to a depth
of 25.3 (), utilizing deep auxiliary optical and Spitzer/IRAC data to
remove brown dwarf and red interloper galaxy contaminants. Our final sample
consists of 28 candidate galaxies at with . We derive stellar masses of for the sample, suggesting that these
candidates represent some of the most massive galaxies known at this epoch. We
measure the rest-frame UV luminosity function (LF) at , confirming
previous findings of a gradual decline in number density at the bright-end
() that is well described by a double-power law (DPL).
We show that quasar contamination in this magnitude range is expected to be
minimal, in contrast to conclusions from recent pure-parallel Hubble studies.
Our results are up to a factor of ten lower than previous determinations from
optical-only ground-based studies at . We find that
the inclusion of photometry is vital for removing brown-dwarf
contaminants, and samples based on red-optical data alone could be
highly contaminated ( per cent). In comparison with other robust samples, our results further support little evolution in the very
bright-end of the rest-frame UV LF from , potentially signalling a
lack of mass quenching and/or dust obscuration in the most massive galaxies in
the first Gyr.Comment: 15 pages, 6 figures, 5 tables (plus additional figures/tables in
Appendix). Submitted to MNRA
Predicting subjective refraction with dynamic retinal image quality analysis
The aim of this work is to evaluate the performance of a novel algorithm that combines dynamic
wavefront aberrometry data and descriptors of the retinal image quality from objective autorefractor
measurements to predict subjective refraction. We conducted a retrospective study of the prediction
accuracy and precision of the novel algorithm compared to standard search-based retinal image
quality optimization algorithms. Dynamic measurements from 34 adult patients were taken with a
handheld wavefront autorefractor and static data was obtained with a high-end desktop wavefront
aberrometer. The search-based algorithms did not signifcantly improve the results of the desktop
system, while the dynamic approach was able to simultaneously reduce the standard deviation (up
to a 15% for reduction of spherical equivalent power) and the mean bias error of the predictions (up
to 80% reduction of spherical equivalent power) for the handheld aberrometer. These results suggest
that dynamic retinal image analysis can substantially improve the accuracy and precision of the
portable wavefront autorefractor relative to subjective refraction.The authors thanks to Dr. David Friedman (Wilmer Eye Institute, Johns Hopkins University School of Medicine)
and his team for their help with study defnition and data acquisition. Eduardo Lage is funded by the Ramon y
Cajal program from the Spanish Ministry of Economy, Industry and Competitivity (RYC-2016-21125). Carlos
S. Hernandez, and Andrea Gil are funded by the Madrid Regional Government through IND2019/TIC-17116
and IND2020/TIC-17340 grants. Research relating to the autorefractor reported in this publication was partially
support by the National Institute of Biomedical Imaging & Bioengineering and National Eye Institute of the
National Institutes of Health under Award Numbers R43EB024299 and R44EY025452, respectivel
Investigation of the Accuracy of a Low-Cost, Portable Autorefractor to Provide Well-Tolerated Eyeglass Prescriptions: A Randomized Crossover Trial
Purpose: To compare patient preferences for eyeglasses prescribed using a low-cost, portable wavefront autorefractor versus standard subjective refraction (SR). Design: Randomized, cross-over clinical trial. Participants: Patients aged 18 to 40 years presenting with refractive errors (REs) to a tertiary eye hospital in Southern India. Methods: Participants underwent SR followed by autorefraction (AR) using the monocular version of the QuickSee device (PlenOptika Inc). An independent optician, masked to the refraction approach, prepared eyeglasses based on each refraction approach. Participants (masked to refraction source) were randomly assigned to use SR- or AR-based eyeglasses first, followed by the other pair, for 1 week each. At the end of each week, participants had their vision checked and were interviewed about their experience with the eyeglasses. Main Outcome Measures: Patients preferring eyeglasses were chosen using AR and SR. Results: The 400 participants enrolled between March 26, 2018, and August 2, 2019, had a mean (standard deviation) age of 28.4 (6.6) years, and 68.8% were women. There was a strong correlation between spherical equivalents using SR and AR (r = 0.97, P < 0.001) with a mean difference of −0.07 diopters (D) (95% limits of agreement [LoA], −0.68 to 0.83). Of the 301 patients (75.2%) who completed both follow-up visits, 50.5% (n = 152) and 49.5% (n = 149) preferred glasses prescribed using SR and AR, respectively (95% CI, 45.7–56.3; P = 0.86). There were no differences in demographic or vision characteristics between participants with different preferences (P > 0.05 for all). Conclusions: We observed a strong agreement between the prescriptions from SR and AR, and eyeglasses prescribed using SR and AR were equally preferred by patients. Wider use of prescribing based on AR alone in resource-limited settings is supported by these finding
Vision difficulty and dementia: economic hardships among older adults and their caregivers
IntroductionLimited research has examined the economic impact of vision difficulty (VD) and dementia on older adults and their caregivers. We aimed to determine whether older adults with VD and/or dementia, and their caregivers, face more economic hardships than their counterparts without VD or dementia.MethodsWe used cross-sectional data from the 2015 National Health and Aging Trends Study (NHATS), a population-based survey of Medicare beneficiaries, linked to their family/unpaid caregivers from the National Study of Caregiving (NSOC). Regression models characterized the association of VD (self-report), dementia (survey and cognitive assessments), and co-occurring VD and dementia with debt, receiving financial help from relatives, government-based Supplemental Nutrition Assistance Program (SNAP), other food assistance, utility assistance, and caregiver financial difficulty.ResultsThe NHATS sample included 6,879 community-dwelling older adults (5670 no VD/dementia, 494 VD-alone, 512 dementia-alone, 203 co-occurring VD and dementia). Adults with VD and dementia had higher odds of receiving SNAP benefits (OR = 2.6, 95%CI = 1.4–4.8) and other food assistance (OR = 4.1, 95%CI = 1.8–9.1) than adults without VD/dementia, while no differences were noted for debt, financial help, and utility assistance. Adults with VD-alone had higher odds of debt (OR = 2.1, 95%CI = 1.3–3.2), receiving financial help (OR = 1.7, 95%CI = 1.1–2.5) and other food assistance (OR = 2.7, 95%CI = 1.7–4.3); while adults with dementia-alone had higher odds of debt (OR = 2.8, 95%CI = 1.4–5.5). The NSOC sample included 1,759 caregivers (995 caring for adults without VD/dementia, 223 for VD-alone, 368 for dementia-alone, and 173 for co-occurring VD and dementia). Compared to caregivers of older adults without VD/dementia, caregivers of adults with VD and dementia had higher odds of financial difficulty (OR = 3.0, 95%CI = 1.7–5.3) while caregivers of adults with VD-alone or dementia-alone did not.DiscussionWhile older adults with VD- or dementia-alone experienced increased economic hardships, disparities in food assistance were amplified among older adults with co-occurring disease. Caregivers of adults with co-occurring disease experienced more financial difficulty than caregivers of adults with a single or no disease. This study highlights the need for interventions across clinical and social services to support the economic wellbeing of our aging population and their caregivers
Ataxin-1 Fusion Partners Alter PolyQ Lethality and Aggregation
Intranuclear inclusion bodies (IBs) are the histopathologic markers of multiple protein folding diseases. IB formation has been extensively studied using fluorescent fusion products of pathogenic polyglutamine (polyQ) expressing proteins. These studies have been informative in determining the cellular targets of expanded polyQ protein as well as the methods by which cells rid themselves of IBs. The experimental thrust has been to intervene in the process of polyQ aggregation in an attempt to alleviate cytotoxicity. However new data argues against the notion that polyQ aggregation and cytotoxicity are inextricably linked processes. We reasoned that changing the protein context of a disease causing polyQ protein could accelerate its precipitation as an IB, potentially reducing its cytotoxicity. Our experimental strategy simply exploited the fact that conjoined proteins influence each others folding and aggregation properties. We fused a full-length pathogenic ataxin-1 construct to fluorescent tags (GFP and DsRed1-E5) that exist at different oligomeric states. The spectral properties of the DsRed1-E5-ataxin-1 transfectants had the additional advantage of allowing us to correlate fluorochrome maturation with cytotoxicity. Each fusion protein expressed a distinct cytotoxicity and IB morphology. Flow cytometric analyses of transfectants expressing the greatest fluorescent signals revealed that the DsRed1-E5-ataxin-1 fusion was more toxic than GFP fused ataxin-1 (31.8±4.5% cell death versus 12.85±3%), although co-transfection with the GFP fusion inhibited maturation of the DsRed1-E5 fluorochrome and diminished the toxicity of the DsRed1-E5-ataxin-1 fusion. These data show that polyQ driven aggregation can be influenced by fusion partners to generate species with different toxic properties and provide new opportunities to study IB aggregation, maturation and lethality
TGF-beta triggers rapid fibrillogenesis via a Novel T beta RII-Dependent Fibronectin-Trafficking Mechanism
Fibronectin (FN) is a critical regulator of extracellular matrix (ECM) remodeling through its availability and stepwise polymerization for fibrillogenesis. Availability of FN is regulated by its synthesis and turnover, and fibrillogenesis is a multistep, integrin-dependent process essential for cell migration, proliferation, and tissue function. Transforming growth factor β (TGF-β) is an established regulator of ECM remodeling via transcriptional control of ECM proteins. Here we show that TGF-β, through increased FN trafficking in a transcription- and SMAD-independent manner, is a direct and rapid inducer of the fibrillogenesis required for TGF-β–induced cell migration. Whereas TGF-β signaling is dispensable for rapid fibrillogenesis, stable interactions between the cytoplasmic domain of the type II TGF-β receptor (TβRII) and the FN receptor (α5β1 integrin) are required. We find that, in response to TGF-β, cell surface–internalized FN is not degraded by the lysosome but instead undergoes recycling and incorporation into fibrils, a process dependent on TβRII. These findings are the first to show direct use of trafficked and recycled FN for fibrillogenesis, with a striking role for TGF-β in this process. Given the significant physiological consequences associated with FN availability and polymerization, our findings provide new insights into the regulation of fibrillogenesis for cellular homeostasis
Erratum to: Is Sensory Loss an Understudied Risk Factor for Frailty? A Systematic Review and Meta-analysis
In the article “Is Sensory Loss an Understudied Risk Factor for Frailty? A Systematic Review and Meta-analysis,” an author was missing. Ana Maseda should be listed as the 11th author. The correct author list is: Benjamin Kye Jyn Tan, Ryan Eyn Kidd Man, Alfred Tau Liang Gan, Eva K Fenwick, Varshini Varadaraj, Bonnielin K Swenor, Preeti Gupta, Tien Yin Wong, Caterina Trevisan, Laura Lorenzo-López, Ana Maseda, José Carlos Millán-Calenti, Carla Helena Augustin Schwanke, Ann Liljas, Soham Al Snih, Yasuharu Tokuda, Ecosse Luc Lamoureux. This error has been corrected
MIGHTEE: multi-wavelength counterparts in the COSMOS field
In this paper we combine the Early Science radio continuum data from the
MeerKAT International GHz Tiered Extragalactic Exploration (MIGHTEE) Survey,
with optical and near-infrared data and release the cross-matched catalogues.
The radio data used in this work covers deg of the COSMOS field,
reaches a thermal noise of Jy/beam and contains radio
components. We visually inspect and cross-match the radio sample with optical
and near-infrared data from the Hyper Suprime-Cam (HSC) and UltraVISTA surveys.
This allows the properties of active galactic nuclei and star-forming
populations of galaxies to be probed out to . Additionally, we use
the likelihood ratio method to automatically cross-match the radio and optical
catalogues and compare this to the visually cross-matched catalogue. We find
that 94 per cent of our radio source catalogue can be matched with this method,
with a reliability of per cent. We proceed to show that visual
classification will still remain an essential process for the cross-matching of
complex and extended radio sources. In the near future, the MIGHTEE survey will
be expanded in area to cover a total of 20~deg; thus the combination
of automated and visual identification will be critical. We compare redshift
distribution of SFG and AGN to the SKADS and T-RECS simulations and find more
AGN than predicted at .Comment: 15 pages, 15 figures. Accepted for publication in MNRA
pcrEfficiency: a Web tool for PCR amplification efficiency prediction
<p>Abstract</p> <p>Background</p> <p>Relative calculation of differential gene expression in quantitative PCR reactions requires comparison between amplification experiments that include reference genes and genes under study. Ignoring the differences between their efficiencies may lead to miscalculation of gene expression even with the same starting amount of template. Although there are several tools performing PCR primer design, there is no tool available that predicts PCR efficiency for a given amplicon and primer pair.</p> <p>Results</p> <p>We have used a statistical approach based on 90 primer pair combinations amplifying templates from bacteria, yeast, plants and humans, ranging in size between 74 and 907 bp to identify the parameters that affect PCR efficiency. We developed a generalized additive model fitting the data and constructed an open source Web interface that allows the obtention of oligonucleotides optimized for PCR with predicted amplification efficiencies starting from a given sequence.</p> <p>Conclusions</p> <p>pcrEfficiency provides an easy-to-use web interface allowing the prediction of PCR efficiencies prior to web lab experiments thus easing quantitative real-time PCR set-up. A web-based service as well the source code are provided freely at <url>http://srvgen.upct.es/efficiency.html</url> under the GPL v2 license.</p
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