VENµS-Derived NDVI and REIP at Different View Azimuth Angles

The bidirectional reflectance distribution function (BRDF) is crucial in determining the quantity of reflected light on the earth’s surface as a function of solar and view angles (i.e., azimuth and zenith angles). The Vegetation and ENvironment monitoring Micro-Satellite (VENµS) provides a unique opportunity to acquire data from the same site, with the same sensor, with almost constant solar and view zenith angles from two (or more) view azimuth angles. The present study was aimed at exploring the view angles’ effect on the stability of the values of albedo and of two vegetation indices (VIs): the normalized difference vegetation index (NDVI) and the red-edge inflection point (REIP). These products were calculated over three polygons representing urban and cultivated areas in April, June, and September 2018, under a minimal time difference of less than two minutes. Arithmetic differences of VIs and a change vector analysis (CVA) were performed. The results show that in urban areas, there was no difference between the VIs, whereas in the well-developed field crop canopy, the REIP was less affected by the view azimuth angle than the NDVI. Results suggest that REIP is a more appropriate index than NDVI for field crop studies and monitoring. This conclusion can be applied in a constellation of satellites that monitor ground features simultaneously but from different view azimuth angles.

Обобщенная нуль-эллипсометрия в схеме "поляризатор-образец-анализатор"

The null-method in generalized ellipsometry with the use of the compensator-free “polarizer ‒ sample ‒ analyzer” scheme is considered for the case of s- and p-polarized incident light on an anisotropic system. Analytical expressions are given that connect the measured angular value — the analyzer azimuth at the detected radiation intensity minimum — with the (2x2) anisotropic Jones matrix elements. To determine the optical and geometric parameters of the studied anisotropic systems, it is proposed to use this value’s dependence on the sample orientation (azimuth). The method sensitivity is estimated. It was found that it is comparable to the sensitivity of the “polarizer‒compensator‒sample‒analyzer” scheme. A comparative analysis of this method and the known photometric method of generalized ellipsometry in the “polarizer-sample-analyzer” scheme based on measuring the dependence of the reflected light intensity on the sample azimuth at the fixed polarizer and analyzer positions is carried out. It is estimated that, to obtain the same sensitivity of these two methods, the one arc minute error in the proposed method corresponds to the 0.05% relative error in determining the energy reflection coefficient in the photometric method.

Синхронное управление прошедшим и отраженными светом в полупроводниковых хромхалькогенидных шпинелях

A way for synchronous control of the intensity of transmitted and reflected light in magnetic semiconductors by an external magnetic field is proposed in the infrared spectral region. For illustration, we obtained the magnetoreflection and magnetotransmission spectra of unpolarized light in single crystals of Hg(Cd)Cr2Se4 spinel.

Joining of CFRT-steel hybrid parts via hole-forming and subsequent pin caulking

In times of increasing global warming, the awareness of the necessity for significant CO2 reduction is growing. Especially in the transport and aerospace sector, lightweight construction has potential to achieve emission reduction goals by reducing the overall vehicle weight. Thereby, adding lightweight fibre-reinforced composites to materials such as steel and aluminium is used to achieve weight savings. Furthermore, continuous-fibre-reinforced thermoplastics (CFRTs) begin to replace more traditional thermoset thermoplastics due to their easier bulk production and uncomplicated storage. Hybrid parts often consist of a CFRT and a higher strength metal component. Here, the joining process poses the main challenge, due to different chemical and physical properties of the components. In the current state of the art, riveted and bolted joints are commonly used, leading to increased weight due to auxiliary elements and requiring precise bolt holes often destroying load-bearing fibres. Joining with cold formed pin structures is an innovative and versatile joining process, which avoids the need for auxiliary elements. These pins are subsequently inserted in warm formed holes in the CFRT component and then caulked to create a form-fitting hybrid joint. To obtain a fundamental understanding of this joining process, hole-forming and pin-caulking, are investigated in this study. First, the hole-forming with IR-radiation is investigated with regard to suitable process parameters and resulting fibre morphology. The formed holes are consequently mechanically characterized. Second, the caulking-process is investigated by iteratively upsetting a pin and subsequently measuring the geometry. Based on these findings two different suitable caulking degrees are defined and samples for mechanical as well as microscopic investigations are manufactured. The created joints are first investigated via micro-sections and reflected light microscopy to identify possible damage in the CFRT component, which can result from the pin caulking process. Second, a mechanical characterisation under shear load as well as pin extraction loads normal to the sample surface is conducted and the normal load tests are compared with the bearing strength of CFRT samples.

Fossilization of Precambrian microfossils in the Volyn pegmatite, Ukraine

We report on Precambrian soft-tissue microfossils from igneous rocks of the Volyn pegmatite district, associated with the Paleoproterozoic Korosten Pluton, north-western Ukraine. The fossils were recovered from m-sized miarolitic cavities and show a well-preserved 3D morphology, mostly fibrous, but with a large variety of fiber types, and also in irregular, flaky shapes reminiscent of former biofilms, and rare spherical objects. Based on literature data, own pyrolysis experiments and reflected light microscopy results, the organic matter (OM) is characterized as (oxy)kerite. Further investigations with microscopic techniques, including scanning and transmission electron microscopy, and electron microprobe analysis show that fossilization likely occurred during a hydrothermal, post-pegmatitic event, by silicification dominantly in the outermost 1–2 µm of the microfossils. The hydrothermal fluid, derived from the pegmatitic environment, was enriched in SiF4, Al, Ca, Na, K, Cl, and S. The OM shows O enrichment where N and S content is low, indicating simultaneous N and S loss during anaerobic oxidation. Mineralization with Al-silicates starts at the rim of the microfossils, continues in its outer parts into identifiable encrustations and intergrowths of clay minerals, feldspar, Ca-sulfate, Ca-phosphate, Fe-sulfide, and fluorite. Breccias, formed during collapse of some the miarolitic cavities, contain also decaying OM, which released high concentrations of dissolved NH4+, responsible for the late-stage formation of buddingtonite and tobelite-rich muscovite. The age of the fossils can be restricted to the time between the pegmatite formation, at ~1.760 Ga, and the breccia formation at ~ 1.49 Ga. As geological environment for growth of the microorganisms and fossilization we assume a geyser system, in which the essential biological components C, N, S, and P for growth of the orgabisms n the miarolitic caves were derived from microorganisms at the surface. Fossilization was induced by magmatic SiF4-rich fluids. The Volyn occurrence is a prime example of Precambrian fossils and the results underline the importance of cavities in granitic rocks as a possible habitat for microorganisms of the deep biosphere.

Ferrotorryweiserite, Rh5Fe10S16, a New Mineral Species from the Sisim Placer Zone, Eastern Sayans, Russia, and the Torryweiserite–Ferrotorryweiserite Series

Ferrotorryweiserite, Rh5Fe10S16, occurs as small grains (≤20 µm) among droplet-like inclusions (up to 50 μm in diameter) of platinum-group minerals (PGM), in association with oberthürite or Rh-bearing pentlandite, laurite, and a Pt-Pd-Fe alloy (likely isoferroplatinum and Fe-Pd-enriched platinum), hosted by placer grains of Os-Ir alloy (≤0.5 mm) in the River Ko deposit. The latter is a part of the Sisim placer zone, which is likely derived from ultramafic units of the Lysanskiy layered complex, southern Krasnoyarskiy kray, Russia. The mineral is opaque, gray to brownish gray in reflected light, very weakly bireflectant, not pleochroic to weakly pleochroic (grayish to light brown tints), and weakly anisotropic. The calculated density is 5.93 g·cm–3. Mean results (and ranges) of four WDS analyses are: Ir 18.68 (15.55–21.96), Rh 18.34 (16.32–20.32), Pt 0.64 (0.19–1.14), Ru 0.03 (0.00–0.13), Os 0.07 (0.02–0.17), Fe 14.14 (13.63–14.64), Ni 13.63 (12.58–14.66), Cu 4.97 (3.42–6.41), Co 0.09 (0.07–0.11), S 29.06 (28.48–29.44), and total 99.66 wt. %. They correspond to the following formula calculated for a total of 31 atoms per formula unit: (Rh3.16Ir1.72Pt0.06Ru0.01Os0.01)Σ4.95(Fe4.48Ni4.11Cu1.38Co0.03)Σ10.00S16.05. The results of synchrotron micro-Laue diffraction studies indicate that ferrotorryweiserite is trigonal; its probable space group is Rm (#166) based on its Ni-analog, torryweiserite. The unit-cell parameters refined from 177 reflections are a = 7.069 (2) Å, c = 34.286 (11) Å, V = 1484 (1) Å3, and Z = 3. The c:a ratio is 4.8502. The strongest eight peaks in the X-ray diffraction pattern derived from results of micro-Laue diffraction study [d in Å(hkil)(I)] are 2.7950 (205) (100); 5.7143 (0006) (60); 1.7671 (220) (44.4); 3.0486 (201) (39.4); 5.7650 (102) (38.6); 2.5956 (207) (37.8); 3.0058 (116) (36.5); and 1.5029 (412) (35.3). Ferrotorryweiserite and the associated PGM crystallized from microvolumes of residual melt at late stages of crystallization of grains of Os- and Ir-dominant alloys occurred in lode zones of chromitites of the Lysanskiy layered complex. In a particular case, the residual melt is disposed peripherally around a core containing a disequilibrium association of magnesian olivine (Fo72.9–75.6) and albite (Ab81.6–86.4), with the development of skeletal crystals of titaniferous augite: Wo40.8–43.2En26.5–29.3Fs20.3–22.6Aeg6.9–9.5 (2.82–3.12 wt. % TiO2). Ferrotorryweiserite represents the Fe-dominant analog of torryweiserite. We also report occurrences of ferrotorryweiserite in the Marathon deposit, Coldwell Complex, Ontario, Canada, and infer the existence of the torryweiserite–ferrotorryweiserite solid solution in other deposits and complexes.

Guillain Barre Syndrome: A Case Report and Literature Review

Introduction: The arrival of Guillain-Barre Syndrome is sudden. It’s a type of neuropathy caused by the immune system. Nutrition is very crucial. In impoverished countries, it is a disabling disease. Autoantibodies against diverse antigens can be seen in the outlying site. The occurrence links 0.4 to 1.7 million individuals per year. Case Presentation: A 5-year-old boy was taken to the hospital with chief complaints of Weakness in bilateral upper and lower limbs, trouble in swallowing, inability to hold the neck, mouth-frothing, fever spikes. On physical examination, the patient has experienced weakness in bilateral upper and lower limbs, Bulbar weakness is present, pain experienced in both legs, the gag reflex is absent, In Cardiovascular System, S1 and S2 sound are present, In Respiratory System, Air entry is bilaterally equal, pupils are reflected light, tone, and power of upper and lower limbs are decreased, then treatment was started as soon as possible, he has not improved after receiving treatment, and the patient is on ventilator support, with treatment continuing until the end of my care. Conclusion: In this study, we primarily focus on professional management, and outstanding nursing care may give the holistic care that Guillain Barre Syndrome requires while also effectively managing the challenging case. The comprehensive health care team collaborates to help the patient achieve their prior level of independence and satisfaction after a full recovery.

Linking Serpentinization and Weathering of Peridotite: A Study on the Mineralogical and Geochemical Evolution of the Sta. Cruz Nickel Laterite Deposit, Zambales, Philippines

While there are extensive studies on the mineralogy and geochemistry of laterites worldwide, the temporal and spatial mineralogical development of a typical nickel laterite profile is still poorly constrained. In this study, we present a detailed mineralogical and geochemical characterization of samples systematically collected from a nickel laterite profile at the Sta. Cruz nickel laterite deposit, Zambales, Philippines, to describe the temporal and spatial development of the laterite profile. Wavelength-dispersive X-ray fluorescence spectroscopy (WDSXRF), mass balance-element mobility calculations, transmitted and reflected light microscopy, and previously reported results from coupled X-ray diffraction (XRD) and Rietveld refinement analyses, reveal that the laterite profile investigated is composed of two main horizons: the limonite and saprolite zones, separated by a thin transitional zone. The main zones are further subdivided into subzones based primarily on the mineral assemblage and major element chemistry: upper limonite, lower limonite, transitional zone, upper saprolite, and lower saprolite. Late-stage garnierite veins were observed cutting the upper and lower saprolite subzones. Investigation of the structure of goethite within the limonite zone via Rietveld refinement show that the crystallinity of goethite decreases with increasing Ni content and increasing crystallite size. This suggests that upwards through the limonite zone, as goethite ages, its crystallinity increases which possibly results in the removal of Ni from its crystal structure and eventual remobilization to the lower laterite zones. We propose a spatio-temporal model of the formation of the Sta. Cruz laterite consisting of four stages: (1) early-stage alteration, (2) continued serpentinization and volume expansion, (3) late stage serpentinization and incipient oxide formation, and (4) goethite ageing and garnierite formation.

PILOMATRIXOMA OF FACE PRESENTING AS PAROTID SWELLING

Pilomatrixoma, also known as pilomatrixoma or calcifying epithelioma of Malherbe, is a benign tumor of skin appendages. Although it is an uncommon and benign neoplasm of the head and neck region, it may sometimes become malignant. It arises from the cells of the outer sheath of the hair follicle root. Owing to its rarity, pilomatrixoma can be missed during differential diagnosis, and it can be misdiagnosed as malignancy. Therefore, for definitive and confirmatory diagnosis, histopathological analysis is imperative. We report a case of a 26-year-old female who presented with hard swelling on the right side of her face near the angle of the mandible. We have discussed its clinical, radiological, and histological findings and reflected light on the treatment of choice for pilomatrixoma.