Restricted Spectral Range Research Articles

Protein content prediction in single wheat kernels using hyperspectral imaging

Hyperspectral imaging (HSI) combines Near-infrared (NIR) spectroscopy and digital imaging to give information about the chemical properties of objects and their spatial distribution. Protein content is one of the most important quality factors in wheat. It is known to vary widely depending on the cultivar, agronomic and climatic conditions. However, little information is known about single kernel protein variation within batches. The aim of the present work was to measure the distribution of protein content in whole wheat kernels on a single kernel basis, and to apply HSI to predict this distribution.Wheat samples from 2013 and 2014 harvests were sourced from UK millers and wheat breeders, and individual kernels were analysed by HSI and by the Dumas combustion method for total protein content. HSI was applied in the spectral region 980–2500nm in reflectance mode using the push-broom approach. Single kernel spectra were used to develop partial least squares (PLS) regression models for protein prediction of intact single grains.The protein content ranged from 6.2 to 19.8% (“as-is” basis), with significantly higher values for hard wheats. The performance of the calibration model was evaluated using the coefficient of determination (R2) and the root mean square error (RMSE) from 3250 samples used for calibration and 868 used for external validation. The calibration performance for single kernel protein content was R2 of 0.82 and 0.79, and RMSE of 0.86 and 0.94% for the calibration and validation dataset, enabling quantification of the protein distribution between kernels and even visualisation within the same kernel. The performance of the single kernel measurement was poorer than that typically obtained for bulk samples, but is acceptable for some specific applications. The use of separate calibrations built by separating hard and soft wheat, or on kernels placed on similar orientation did not greatly improve the prediction ability. We simulated the use of the lower cost InGaAs detector (1000–1700nm), and reported that the use of proposed HgCdTe detectors over a restricted spectral range gave a lower prediction error (RMSEC=0.86% vs 1.06%, for HgCdTe and InGaAs, respectively), and increased R2 value (Rc2=0.82 vs 0.73).

X-ray continuum as a measure of pressure and fuel–shell mix in compressed isobaric hydrogen implosion cores

Pressure, by definition, characterizes the conditions within an isobaric implosion core at peak compression [Gus'kov et al., Nucl. Fusion 16, 957 (1976); Betti et al., Phys. Plasmas 8, 5257 (2001)] and is a key parameter in quantifying its near-ignition performance [Lawson, Proc. Phys. Soc. London, B 70, 6 (1957); Betti et al., Phys. Plasmas 17, 058102 (2010); Goncharov et al., Phys. Plasmas 21, 056315 (2014); and Glenzer et al., Phys. Plasmas 19, 056318 (2012)]. At high spectral energy, where the x-ray emission from an imploded hydrogen core is optically thin, the emissivity profile can be inferred from the spatially resolved core emission. This emissivity, which can be modeled accurately under hot-core conditions, is dependent almost entirely on the pressure when measured within a restricted spectral range matched to the temperature range anticipated for the emitting volume. In this way, the hot core pressure at the time of peak emission can be inferred from the measured free-free emissivity profile. The pressure and temperature dependences of the x-ray emissivity and the neutron-production rate explain a simple scaling of the total filtered x-ray emission as a constant power of the total neutron yield for implosions of targets of similar design over a broad range of shell implosion isentropes. This scaling behavior has been seen in implosion simulations and is confirmed by measurements of high-isentrope implosions [Sangster et al., Phys. Plasmas 20, 056317 (2013)] on the OMEGA laser system [Boehly et al., Opt. Commun. 133, 495 (1997)]. Attributing the excess emission from less-stable, low-isentrope implosions, above the level expected from this neutron-yield scaling, to the higher emissivity of shell carbon mixed into the implosion's central hot spot, the hot-spot “fuel–shell” mix mass can be inferred.

Panchromatic averaged stellar populations

We study how the spectral fitting of galaxies, in terms of light fractions, derived in one spectral region translates into another region, by using results from evolutionary synthesis models. In particular, we examine propagation dependencies on evolutionary population synthesis (EPS) models (grasil, galev, Maraston and galaxev), age, metallicity and stellar evolution tracks over the near-ultraviolet–near-infrared (NUV–NIR, 3500 Å to 2.5 μm) spectral region. Our main results are as follows: as expected, young (t≲ 400 Myr) stellar population fractions derived in the optical cannot be directly compared to those derived in the NIR, and vice versa. In contrast, intermediate to old age (t≳ 500 Myr) fractions are similar over the whole spectral region studied. The metallicity has a negligible effect on the propagation of the stellar population fractions derived from NUV to NIR. The same applies to the different EPS models, but restricted to the range between 3800 and 9000 Å. However, a discrepancy between galev/Maraston and grasil/galaxev models occurs in the NIR. Furthermore, the initial mass function is not important for the synthesis propagation. Compared to starlight synthesis results, our propagation predictions agree at ∼95 per cent confidence level in the optical, and ∼85 per cent in the NIR. In summary, spectral fitting performed in a restricted spectral range should not be directly propagated from the NIR to the UV/optical, or vice versa. We provide equations and an on-line form [panchromatic averaged stellar population (PaASP)] to be used for this purpose.

Infrared spectroscopy: a reagent-free method to distinguish Alzheimer's disease patients from normal-aging subjects

The physiopathogenesis of Alzheimer's disease (AD) is related to various biochemical mechanisms that may be reflected by changes in plasma components. In the current study, Fourier transform-infrared (FT-IR) spectroscopy was used to identify these biochemical variations by monitoring spectral differences in the plasma of 40 AD patients compared with those of 112 control subjects. A hierarchical classification in the whole mid-infrared region allowed a clear separation between AD and controls (C) that was optimized by using a restricted spectral range (1480-1428 cm(-1)). Spectral changes confirmed vibration differences between AD and C mostly related to modified lipid and nucleic acid structures involved in oxidative stress-dependent processes of AD. Moreover, the analysis of samples in the 1480-910-cm(-1) region allowed the distinction between C and AD with an accuracy of 98.4% and showed 2 subgroups C(1) and C(2) within the C group. Interestingly, the C(1) subgroup was located closer to the AD group than the C(2) subgroup, which suggests biochemical differences within the nondemented subjects. Biochemical studies revealed a significant increase in a specific marker of oxidative stress, F8-isoprostanes (8-epi-PGF2alpha) levels, in the plasma of AD patients as compared with total controls and subgroup C(2) but not subgroup C(1). Thus, these results suggest that use of FT-IR spectroscopy could be valuable to distinguish AD patients from normal-aging subjects.

Development and Applications of Continuous-Wave Cavity Ring-Down Spectroscopy

Continuous-wave cavity ring-down spectroscopy (CW-CRDS) (using continuous-wave lasers) is now in widespread use for the sensitive detection of a range of different trace-gas species, including water vapor as a very important trace contaminant in many gases. It has also now been applied to monitor trace water vapor in a range of matrix gases, including those that are corrosive and have the potential for spectral interference with the target water-vapor species. The developments that have been carried out to achieve this will be discussed, and some of the applications, covering single sensors and multi-head sensors, will be presented. One limitation of the current sensor technology is that it uses mirrors that are highly reflective over a very restricted spectral range, and this limits a given sensor to the measurement of one or two gaseous species. Measurements of other species require the mirrors to be changed, as it is not currently practical to obtain mirrors with the required high reflectivity that also cover a large spectral range. The development of a new type of ring-down cavity that uses uncoated reflective optics, and which can be used from the ultraviolet to the infrared spectral regions, is presented. Examples of industrial and scientific applications are also presented.

NUMERICAL MODELING OF UNSTEADY RADIATIVE-CONVECTIVE HEAT TRANSFER ON A FLAT-PLATE BOUNDARY LAYER IN A SELECTIVELY EMITTING AND SCATTERING MEDIUM

A conjugation problem for radiative–convective heat transfer in a turbulent flow of a high–temperature gas—particle medium around a thermally thin plate is considered. The plate experiences intense heating from an outside source that emits radiation in a restricted spectral range. Unsteady temperature fields and heat–flux distributions along the plate are calculated. The results permit prediction of the effect of the type and concentration of particles on the dynamics of the thermal state of both the medium in the boundary layer and the plate itself under conditions of its outside heating by a high–temperature source of radiation.

The use of restricted spectral range red lenses for the diagnosis and relief of dazzlement of a rod monochromat

An infant rod monochromat was diagnosed and was then treated with the Younger PLS 550 lens. The comparison in use of PLS 550 and a neutral density lens confirmed the presence of cone dysfunction. The use of this lens takes advantage of the spectral shift in luminosity between rods and cones. Younger PLS 550 and PLS 530 tints are used for the relief of photophobia according to prevailing brightness. This paper discusses patient management with the use of these lenses and some characteristics of the vision of a rod monochromat.

Stigmatic coma free VUV devices for high resolution line profiles measurements

Optical devices for line profile measurements must have a symmetrical instrumental profile to allow the use of classical deconvolution methods. Such devices must be then coma free and simultaneously the astigmatic curvature must be eliminated. In a first approach we consider a modified version of a Rowland circle set-up, and in a second one, a new type of stigmatic and coma free spectrometer fitted with spherical holographic gratings each of them covering a restricted spectral range.

High Resolution X-Ray Spectroscopy of The Gas Surrounding M87 and NGC1275: Emission Line Detection and Evidence for Radiatively Regulated Accretion

The topic of this paper really falls somewhere between this session on active galaxies and the session on clusters. What I will report is really a cluster phenomenon but one which depends on the presence of a dominant, massive galaxy in the cluster. Specifically, we have detected several X-ray emission lines from the vicinity of M87 in the Virgo Cluster and NGC 1275 in Perseus. The lines are indicative of material which is cooler than the bulk of the intracluster gas. This material is most likely accreting onto the central galaxy with the accretion rate controlled by the rate of radiative cooling.The observations I am reporting were made with the Focal Plane Crystal Spectrometer (FPCS)on the Einstein Observatory. The instrument is a Bragg crystal spectrometer which has a resolving power (E/ΔE) of 50 to 500 over the energy range of 0.2 to 3 keV. It operates much like an optical scanner in that it has a narrow passband which is swept over some restricted spectral range containing an emission line. Detailed descriptions are given elsewhere (Canizares et al. 1977, 1979, Giacconi et al. 1979).

The refractive error of the fish eye

Goldfish eyes were rapidly frozen and sectioned and the lens radii and distances between the lens and the two retinal surfaces were measured. These measurements were used to calculate the refractive error at each of the two retinal surfaces. A comparison with refractive errors determined with a retinoscope just prior to freezing indicates that, in fish, the retinoscopic finding is based upon reflection from the retina-choroid border and not from the retina-vitreous surface. A subsequent examination of longitudinal chromatic aberration of fish lenses indicates that a substantial amount of chromatic aberration exists. The consideration of this finding in association with the restricted spectral range ol aquatic habitats suggests that the fish eye is less hyperopic in its natural environment than that found using conventional non-monochromatic measurements of refractive error.

Die vervollständigung des termschemas von Zn I mit hilfe einer hohlkathodenentladung

Spectra of Zn I obtained with a specially designed hollow-cathode device show many lines corresponding to “forbidden transitions”. Analysing these transitions, it is possible to obtain the position of a number of hitherto unknown high-lying energy terms of the Zn I atom. “Allowed” transitions from these terms lead to spectral lines situated in the far infra-red, a direct measurement of which would cause considerable difficulties. Observing the forbidden transitions, it is sufficient to investigate only a very restricted spectral range in the near u.v. to obtain quite a number of F, G, H, J terms and also some further additional terms to already known series of the Triplet System of Zn I. At the end of this paper a critical discussion of the published wavelengths is presented.