127 research outputs found
A comparison of variate pre-selection methods for use in partial least squares regression: a case study on NIR spectroscopy applied to monitoring beer fermentation
This work investigates four methods of selecting variates from near-infrared (NIR) spectra for use
in partial least squares (PLS) regression models to predict biomass and chemical changes during beer
fermentation. The fermentation parameters studied were ethanol concentration, specific gravity (SG), optical
density (OD) and dry cell weight (DCW). The four selection methods investigated were: Simple, where a
fingerprint region is chosen manually; CovProc, a covariance procedure where variates are introduced
based on the magnitude of the 1st PLS vector coefficients; CovProc-SavGo, a modification to CovProc
where the window size of a Savitzky-Golay filter applied to the spectra is also optimised; and Genetic
Algorithm (GA), where variates are selected based on the frequency of appearance in 8-variate multiple
linear regression models found from repeated execution of the GA routine. The analysis found that all four
methods produced good predictive models. The GA approach produced the lowest standard error in
prediction (SEP) based on leave-one-out cross validation (LOO-CV), although this advantage was not reflected in the standard error in validation values, SEV, where all four models performed comparably. From
this work, we would recommend using the Simple approach if a suitable fingerprint region can be identified,
and using CovProc otherwise
Recommended from our members
The chemical composition of insecticides and fungicides
Published December 1925. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
Cameras, Coyotes, and the Assumption of Equal Detectability
Remote cameras are an increasingly important tool in management and wildlife studies. However, we often do not know if they provide an unbiased sample of populations. Using a marked, radio-collared population of coyotes (Canis latrans) of known social status, we evaluated the influence of temporal (daily and seasonal) and spatial (distance between units, habitat, and proximity to human structures) factors on vulnerability to photo-captures. During 8 unbaited camera sessions of 6 weeks each, we obtained 158 coyote photographs at a photo-capture success rate of 1.6%. We were able to identify not only marked individuals, but also a number of uncollared adults through variation in their pelage. Photo-capture of adults peaked 2 weeks after we established camera stations. Annual success for photographing adult coyotes was greatest during March and April, which corresponded with the dispersal season. The majority of photo-captures occurred at night, and adult photo-captures peaked around midnight, with smaller peaks at dawn and dusk. Rather than reflecting a circadian activity pattern, nighttime captures seemed to reflect when adult coyotes were most vulnerable to photo-capture. Characteristics of camera locations, such as amount of human activity, being on roads versus trails, and habitat type, also influenced the number of photo-captures. We conclude that remote cameras do not always provide an unbiased sample of populations and that animal behavior is important to consider when using these systems. Researchers using camera techniques need to carefully consider when, where, and how cameras are placed to reduce this bias
The Multiview Observatory for Solar Terrestrial Science (MOST)
We report on a study of the Multiview Observatory for Solar Terrestrial
Science (MOST) mission that will provide comprehensive imagery and time series
data needed to understand the magnetic connection between the solar interior
and the solar atmosphere/inner heliosphere. MOST will build upon the successes
of SOHO and STEREO missions with new views of the Sun and enhanced instrument
capabilities. This article is based on a study conducted at NASA Goddard Space
Flight Center that determined the required instrument refinement, spacecraft
accommodation, launch configuration, and flight dynamics for mission success.
MOST is envisioned as the next generation great observatory positioned to
obtain three-dimensional information of large-scale heliospheric structures
such as coronal mass ejections, stream interaction regions, and the solar wind
itself. The MOST mission consists of 2 pairs of spacecraft located in the
vicinity of Sun-Earth Lagrange points L4 (MOST1, MOST3) and L5 (MOST2 and
MOST4). The spacecraft stationed at L4 (MOST1) and L5 (MOST2) will each carry
seven remote-sensing and three in-situ instrument suites. MOST will also carry
a novel radio package known as the Faraday Effect Tracker of Coronal and
Heliospheric structures (FETCH). FETCH will have polarized radio transmitters
and receivers on all four spacecraft to measure the magnetic content of solar
wind structures propagating from the Sun to Earth using the Faraday rotation
technique. The MOST mission will be able to sample the magnetized plasma
throughout the Sun-Earth connected space during the mission lifetime over a
solar cycle.Comment: 42 pages, 19 figures, 8 tables, to appear in J. Atmospheric and Solar
Terrestrial Physic
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
T cell phenotypes in COVID-19 - a living review
COVID-19 is characterized by profound lymphopenia in the peripheral blood, and the remaining T cells display altered phenotypes, characterized by a spectrum of activation and exhaustion. However, antigen-specific T cell responses are emerging as a crucial mechanism for both clearance of the virus and as the most likely route to long-lasting immune memory that would protect against re-infection. Therefore, T cell responses are also of considerable interest in vaccine development. Furthermore, persistent alterations in T cell subset composition and function post-infection have important implications for patientsâ long-term immune function. In this review, we examine T cell phenotypes, including those of innate T cells, in both peripheral blood and lungs, and consider how key markers of activation and exhaustion correlate with, and may be able to predict, disease severity. We focus on SARS-CoV-2-specific T cells to elucidate markers that may indicate formation of antigen-specific T cell memory. We also examine peripheral T cell phenotypes in recovery and the likelihood of long-lasting immune disruption. Finally, we discuss T cell phenotypes in the lung as important drivers of both virus clearance and tissue damage. As our knowledge of the adaptive immune response to COVID-19 rapidly evolves, it has become clear that while some areas of the T cell response have been investigated in some detail, others, such as the T cell response in children remain largely unexplored. Therefore, this review will also highlight areas where T cell phenotypes require urgent characterisation
The role and uses of antibodies in COVID-19 infections: a living review
Coronavirus disease 2019 has generated a rapidly evolving field of research, with the global scientific community striving for solutions to the current pandemic. Characterizing humoral responses towards SARS-CoV-2, as well as closely related strains, will help determine whether antibodies are central to infection control, and aid the design of therapeutics and vaccine candidates. This review outlines the major aspects of SARS-CoV-2-specific antibody research to date, with a focus on the various prophylactic and therapeutic uses of antibodies to alleviate disease in addition to the potential of cross-reactive therapies and the implications of long-term immunity
Stroke genetics informs drug discovery and risk prediction across ancestries
Previous genome-wide association studies (GWASs) of stroke â the second leading cause of death worldwide â were conducted predominantly in populations of European ancestry1,2. Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (Pâ<â0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis3, and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach4, we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry5. Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries
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