Dark Spots Research Articles

Oil Spill Identification and Monitoring from Sentinel-1 Sar Satellite Earth Observations: a Machine Learning Approach

Identification of an oil spill is essential to evaluate the potential spread and float from the source to coastal terrains, and their continued monitoring is essential for managing the environmental protection actions to confine the pollution and avoid further damage. The SAR sensor is perceived as the most significant remote sensing apparatus for the oil slick examination. One of the main aspects of oil spreading over sea surface is that it dampens the capillary waves and so, the backscatter radio waves are suppressed. As a result, oil spills are represented as black spots, while the brighter regions are usually related with unspoiled polluted sea areas. Additionally, the wide coverage that the sensor can provide is highly significant including long-range fate, as well as contextual information, such as sensitive coastal areas or vessels, which can be enclosed in the acquired image. However, oceanic natural phenomena such as low wind speed regions, weed beds and algae blooms, wave shadows behind land, grease ice, etc. can also be depicted as dark spots. These dark regions are commonly categorized as “look-alikes and their discrimination is very challenging. Machine Learning techniques are the most appropriate choice to classify oil spills and look-alikes. In the present work, a comparison between decision trees models and NN is performed to identify and extract the appropriate set of features characterizing an oil spill allowing effective evolution monitoring and setting up proper emergency actions.

Atmosphere of Betelgeuse before and during the Great Dimming event revealed by tomography

Context. Despite being the best studied red supergiant star in our Galaxy, the physics behind the photometric variability and mass loss of Betelgeuse is poorly understood. Moreover, recently the star has experienced an unusual fading with its visual magnitude reaching a historical minimum. The nature of this event was investigated by several studies where mechanisms, such as episodic mass loss and the presence of dark spots in the photosphere, were invoked. Aims. We aim to relate the atmospheric dynamics of Betelgeuse to its photometric variability, with the main focus on the dimming event. Methods. We used the tomographic method which allowed us to probe different depths in the stellar atmosphere and to recover the corresponding disk-averaged velocity field. The method was applied to a series of high-resolution HERMES observations of Betelgeuse. Variations in the velocity field were then compared with photometric and spectroscopic variations. Results. The tomographic method reveals that the succession of two shocks along our line-of-sight (in February 2018 and January 2019), the second one amplifying the effect of the first one, combined with underlying convection and/or outward motion present at this phase of the 400 d pulsation cycle, produced a rapid expansion of a portion of the atmosphere of Betelgeuse and an outflow between October 2019 and February 2020. This resulted in a sudden increase in molecular opacity in the cooler upper atmosphere of Betelgeuse and, thus, in the observed unusual decrease of the star’s brightness.

Sardinella ventura n. sp. (Actinopterygii: Clupeiformes: Clupeidae), a new sardine from Mauritius.

The new sardine Sardinella ventura n. sp. (Teleostei: Clupeiformes: Clupeidae) is described on the basis of 10 specimens collected from Mauritius. The new species is most similar to Sardinella dayi Regan 1917 in having non-deciduous scales with pores and discontinuous striae, a dark spot on the dorsal-fin origin, the pelvic fin with 8 rays, and similar number of gill rakers, in addition to very similar numbers of keeled scutes. However, the new species is distinguished from S. dayi by having a shorter caudal peduncle [6.27.6% SL (mean 7.0%) vs. 8.212.0% (9.2%) in S. dayi], larger eye [8.49.9% (9.0%) vs. 6.88.0% (7.4%)] and orbit [9.612.3% (10.7%) vs. 8.510.2% (9.3%)], longer pectoral [21.022.7% (21.5%) vs. 17.021.0% (19.8%)] and pelvic fins [12.513.5% (12.8%) vs. 10.412.2% (11.2%)], and a greater numbers of pseudobranchial filaments [1719 (modally 17) vs. 1822 (19)], lateral scale rows in longitudinal series [4143 (41) vs. 3842 (40)] and transverse scales [11 or 12 (12) vs. 11]. There were significant differences in seven meristic and 14 morphometric characters between the two species.

HISEA-1: The First C-Band SAR Miniaturized Satellite for Ocean and Coastal Observation

On 22 December 2020, HISEA-1, the first C-band SAR small satellite for ocean remote sensing, was launched from the coastal Wenchang launch site. Though small in weight, the images it produced have a high spatial resolution of 1 m and a large observation width of 100 km. The first batch of images obtained within the first week after the launch confirmed the rich information in the data, including sea ice, wind, wave, rip currents, vortexes, ships, and oil film on the sea, as well as landmark buildings. Furthermore, geometric characteristics of sea ice, wind vector, ocean wave parameter, 3D features of buildings, and some air-sea interface phenomena in dark spots could also be detected after relevant processing. All these indicate that HISEA-1 could be a reliable, remarkable, and powerful instrument for observing oceans and lands.

Dissemination and clinical and hematological manifestations in cat cestodes

The materials of the presented research cover the issues of the spread of cestodes of cats in the Solomyansky district of Kyiv (according to the veterinary clinic Vet Alliance). After analyzing the relevant scientific literature, the epizootic situation of dipilidiosis and mesocestoidosis of cats in the metropolis was analyzed. Studies have shown that more than 50 % of parasitic diseases in cats occur in associated forms, among which the most common are toxocariasis, dipilidiosis, mesocestoidosis, ktenocephalidosis (flea infestation) and otodectosis. The monoform of invasions occurred only in 14.7 % of registered cases. The spread of diplidiosis and mesocestoidosis was characterized by seasonality – the peak of the lesion cats were observed in September-October. The most susceptible to infection Dipylidium caninum and Mesocestoides lineatus were kittens under the age of six months. The clinical condition and hematological parameters of kittens with dipilidiosis were also studied. Depression, anemia of the conjunctiva and mucous membranes of the nose and mouth, indigestion, dry cough were found. All cats had dull fur, and numerous dark brown spots and live fleas were observed on the skin, especially in the lumbar region. These data indicate a violation of erythropoiesis in feline dipilidiosis, which was characterized by erythrocytopenia and leukocytosis. Significant eosinophilia, an increase in the number of rod-shaped, and a decrease in segmental neutrophils were also found compared with clinically healthy animals. The results of biochemical blood tests of sick cats were important to clarify the features of the pathogenesis of dipilidiosis. Changes in blood biochemical parameters were characterized by a probably reduced content of hemoglobin, total protein and albumin. This indicates not only a violation of erythropoiesis, but also a violation of the protein-synthesizing function of the liver, because the pathological process involves various organs and systems of the body. Key words: feline dipilidiosis, feline mesocestoidosis, prevalence, clinical condition, hematological parameters, pulse rate, mucosal anemia, indigestion.

Two new species of Hypostomus suckermouth-armoured catfishes (Teleostei: Loricariidae) from central Brazil.

This study describes two new endemic Hypostomus species from central Brazil, which were previously identified as genetically distinct lineages in a recent genomic study that recommended their testing and potential description based on morphological data. A machine learning classification procedure (random forest) was used to investigate morphological variation and identify putatively diagnostic characters for these candidate species and revealed that each is morphologically distinct. The new species Hypostomus cafuringa is characterized by small size, dark spots under a light background, deeper caudal peduncle and shorter first ray of the pectoral fin and base of the dorsal fin when compared to congeneric species from the region. H. cafuringa is known from the headwaters of the Maranhão River, upper Tocantins River basin, Distrito Federal, Brazil. The second new species, Hypostomus crulsi, is characterized by dark spots under a light background, absence of plates along the abdomen region, shorter first ray of the pelvic fin, shorter first ray of the pectoral fin and smaller body size. H. crulsi is known from the headwaters of the São Bartolomeu River, upper Paraná River basin, Distrito Federal, Brazil. The rapid conversion of natural habitats for agricultural development and the isolation of protected areas represent a serious threat to the continued existence of these two newly described endemic species, which warrant conservation assessment.

Effective Failure Analysis for Packaged Semiconductor Lasers with a Simple Sample Preparation and Home-Made PEM System

As the application requirements of semiconductor lasers continue to increase, severe challenges are brought to the reliability of semiconductor lasers. In order to promote the study of laser failure, this paper proposes an effective failure analysis method for packaged semiconductor lasers with a simple sample preparation and home-made photon emission microscopy (PEM) system. The new simple sample preparation process for failure analysis is presented and the necessary polishing fixture is designed so that sample can be obtained without expensive and complex micro-/nano-processing. Two types of home-made PEM experimental systems were established for observing the failure from the front facet and active region of semiconductor lasers. Experimental results showed that, with the proposed sample preparation flow, the home-made PEM experimental system effectively observed the leakage defects from the front facet and dark spot defects (DSDs) in the active region of semiconductor lasers. The method can help researchers and laser manufactures to perform effective failure analysis of packaged semiconductor lasers.

Analyzing integrated π…π, C[sbnd]H…π and hydrogen bonding interactions in N, N-Dimethyl-4-aminopyridinium benzilate

Studying the non-covalent interactions is the central core of research for the researchers in supramolecular chemistry. In such a way, a proton transfer molecular salt, N,N-Dimethyl-4-aminopyridinium benzilate (DAPB) has been synthesized and the crystal has been grown by solvent evaporation technique. With the help of Single crystal X-ray diffraction, the supramolecular architecture of the synthesized salt has been investigated and found to be molecule is stabilized by strong NH…O and OH…O hydrogen bonds in addition to other non-covalent interactions such as CH…O, CH…π and π…π interactions. The dark spots on the Hirshfeld surfaces and the proportions on the fingerprints support the nature of various interactions found in the three-dimensional structure. The higher proportion of C…H/H…C contacts pictures out the influence of CH…π stacking interactions over the hydrogen bonding interactions. Theoretical electronic spectral analysis, ESP, NBO and hyperpolarizability analyses were calculated to understand the microscopic properties of the molecule. The presence of inter and intramolecular interactions observed for DAPB are responsible for the increased second hyperpolarisabilities at 1064 nm. Thus, the non-covalent interactions greatly influence the microscopic properties of DAPB.

SAR Oil Spill Detection System through Random Forest Classifiers

A set of open-source routines capable of identifying possible oil-like spills based on two random forest classifiers were developed and tested with a Sentinel-1 SAR image dataset. The first random forest model is an ocean SAR image classifier where the labeling inputs were oil spills, biological films, rain cells, low wind regions, clean sea surface, ships, and terrain. The second one was a SAR image oil detector named “Radar Image Oil Spill Seeker (RIOSS)”, which classified oil-like targets. An optimized feature space to serve as input to such classification models, both in terms of variance and computational efficiency, was developed. It involved an extensive search from 42 image attribute definitions based on their correlations and classifier-based importance estimative. This number included statistics, shape, fractal geometry, texture, and gradient-based attributes. Mixed adaptive thresholding was performed to calculate some of the features studied, returning consistent dark spot segmentation results. The selected attributes were also related to the imaged phenomena’s physical aspects. This process helped us apply the attributes to a random forest, increasing our algorithm’s accuracy up to 90% and its ability to generate even more reliable results.

Study of the physical and chemical origin of features observed in luminescence and thermography images of Cu(In,Ga)Se2

Luminescence and thermography have proven to be effective tools for the detection of failure modes and defects in Cu(In,Ga)Se2 (CIGS)-based photovoltaic (PV) devices. However, the chemical and physical origin of many of the features observed with these techniques are still unclear. This makes it difficult to asses their impact on device performance and lifetime. Here, features were identified in CIGS cells using spatial photoluminescence (PL), electroluminescence (EL), illuminated lock-in thermography (ILIT) and dark lock-in thermography (DLIT). Localized features were studied using optical microscopy, scanning electron microscopy, electron dispersive X-ray spectroscopy and confocal microscopy. The most commonly observed features could be associated with three different origins. Firstly, TCO sheet resistance resulting in a gradient in the direction of current flow was visible in each sample. For samples with high TCO sheet resistance this compromised detection of other features in EL. Secondly, about half of the detected features corresponded to areas of exposed molybdenum resulting in dark spots in PL and EL. These occurred in shunted and non-shunted form, with only the former causing hotspots in thermography. Thirdly, ohmic shunts induced by current-injection (current-induced shunts) were found to form large hotspots in ILIT and DLIT and a significant drop in luminescence intensity in EL and PL. Localized features in luminescence were only observed for the largest current-induced shunts as clear bright spots in PL and clear dark spots in EL. The results from this study contribute to the distinction of different defect types in modules using exclusively luminescence and thermography imaging techniques.

External validation of blue light imaging (BLI) criteria for the optical characterization of colorectal polyps by endoscopy experts.

Recently, the BLI Adenoma Serrated International Classification (BASIC) system was developed by European experts to differentiate colorectal polyps. Our aim was to validate the BASIC classification system among the US-based endoscopy experts. Participants utilized a web-based interactive learning system where the group was asked to characterize polyps using the BASIC criteria: polyp surface (presence of mucus, regular/irregular and [pseudo]depressed), pit appearance (featureless, round/non-round with/without dark spots; homogeneous/heterogeneous distribution with/without focal loss), and vessels (present/absent, lacy, peri-cryptal, irregular). The final testing consisted of reviewing BLI images/videos to determine whether the criteria accurately predicted the histology results. Confidence in adenoma identification (rated "1" to "5") and agreement in polyp (adenoma vs non-adenoma) identification and characterization per BASIC criteria were derived. Strength of interobserver agreement with kappa (k) value was reported for adenoma identification. Ten endoscopy experts from the United States identified conventional adenoma (vs non-adenoma) with 94.4% accuracy, 95.0% sensitivity, 93.8% specificity, 93.8% positive predictive value, and 94.9% negative predictive value using BASIC criteria. Overall strength of interobserver agreement was high: kappa 0.89 (0.82-0.96). Agreement for the individual criteria was as follows: surface mucus (93.8%), regularity (65.6%), type of pit (40.6%), pit visibility (66.9%), pit distribution (57%), vessel visibility (73%), and being lacy (46%) and peri-cryptal (61%). The confidence in diagnosis was rated at high ≥4 in 67% of the cases. A group of US-based endoscopy experts have validated a simple and easily reproducible BLI classification system to characterize colorectal polyps with >90% accuracy and a high level of interobserver agreement.

Daily photoprotection to prevent photoaging

Extrinsic skin aging or photoaging was previously thought to be almost exclusively due to solar ultraviolet (UV) radiation. However, recent literature has described other contributing factors and clarification is thus required as to what extent and what type of daily photoprotection is needed to mitigate extrinsic skin aging. We reviewed the existing scientific evidence on daily photoprotection, and specific requirements at the product level, to prevent extrinsic skin aging. We critically reviewed the existing evidence on potential ecological and toxicological risks which might be associated with daily photoprotection. Evidence shows that broad protection against the entire solar range of UVB, UVA, UVA1, visible light, and short infrared (IRA) is required to prevent extrinsic aging. Other exposome factors, such as air pollution and smoking, also contribute to skin aging. Daily broad-spectrum sunscreen photoprotection should thus contain antioxidant ingredients for additional benefits against UV, IRA, and pollution-induced oxidative stress as well as anti-aging active ingredients to provide clinical benefits against skin aging signs, such as wrinkles and dark spots. Broad-spectrum sunscreen containing pigments, such as iron oxide, may be required for melasma prevention. There is no conclusive clinical evidence that daily sunscreen use is unsafe or that it compromises vitamin D synthesis. Daily use of broad-spectrum sunscreen containing antioxidant and anti-aging active ingredients can effectively reduce extrinsic aging.

Use of simulated vaginal and menstrual fluids to model in vivo discolouration of silicone elastomer vaginal rings

Vaginal rings releasing antiretrovirals – either alone or in combination with contraceptive progestins – are being developed for prevention of human immunodeficiency virus (HIV) transmission via vaginal sex. Following Phase I trials, significant discolouration was observed on the surface of investigational silicone elastomer antiretroviral-contraceptive matrix-type vaginal rings containing either 25 mg dapivirine or 200 mg dapivirine plus levonorgestrel. In this study, potential causes of the discolouration have been assessed in vitro using simulated vaginal and menstrual fluids (SVF and SMF, respectively) to model in vivo exposure. The fluid compositions also included hydrogen peroxide (H2O2), hydrogen peroxide plus a copper intrauterine device (IUD), or synthetic dyes (representing personal care and household cleaning products). No discolouration was observed for rings exposed to SVF + hydrogen peroxide (with or without an IUD). However, the SVF + dye compositions showed significant ring discolouration, with staining patterns similar to those observed with rings that had been exposed to highly-coloured personal care and household cleaning products during clinical trial use. Exposure of rings to SMF compositions invariably caused yellow surface discolouration, dark spotting and markings, similar to the staining patterns observed following clinical use. The darker marks on the ring surface were identified as blood debris derived from the SMF. The study indicates that surface discolouration of rings in vivo can be attributed to exposure to menstrual fluid or highly coloured personal care or household cleaning products. Discolouration of the rings was not associated with any specific safety risks for the user, though severe discolouration could potentially impact acceptability and adherence.

68‐4: A New Thin‐Film Encapsulation Structure for Flexible OLED Display with Long Lifetime

A series of adhesion strength modified layer (ML) was introduced to develop the new TFE structures. The new encapsulation structures provided the long‐life time performance for the flexible OLED device. No pixel shrinkage or dark spots appeared after storing in an environment of 85% humidity and at 85 °C over 20,000 hours. The adhesion strength of the thin film system improved and the risk of peeling decreased.

P‐38: A Study on the Difference of Thermal Behavior by Crystallization Method

Indium‐Tin‐Oxide (ITO) / Ag (Silver) / ITO triple layer, are often used as anode electrodes, but when the Ag is eluted, they cause many problems, such as poor dark spots. In this paper, the thermal behavior of the upper ITO, which is presumed to be the most relevant, was observed to identify the cause of this defect. The ITO layer is deposited in an amorphous state during initial deposition to create a pattern. After patterning, it is crystallized by heat treatment to obtain electrical and physical characteristics. However, it was confirmed that partial crystallization was already in progress at initial deposition due to changes in thickness. Partial crystallization was mainly observed at the meeting points of the three Ag grains. It was also confirmed that the process of heat treatment led to different crystallization than the initial partial crystallization. The crystallization areas formed in these heterogeneous states showed different thermal behavior. Stress caused by different thermal behaviors accelerated as heat treatment progressed, producing pin‐holes after the heat treatment was completed. Thus, the number of pin‐holes increases as heterogeneous states increase, resulting in a difference in the level of Ag elution defect. In conclusion, a decrease in the number of triple points an Ag Grain meets can reduce dissimilarity and consequently reduce the probability of pin‐hole occurrence. Therefore, expanding the size of the Ag Grain is effective in reducing the defect of Ag elution.

THE DATA REDUCTION USING MATLAB FOR DIFFERENT SPECKLE IMAGES FORM SMALL SURFACES ROUGHNESS

The so-called laser speckles are bright spots and dark spots formed when a coherent ray is incident on a rough surface which scattered randomly in all directions, the interference of these scattered rays form these bright and dark spots (Laser Speckles).In this paper we are concerned with the formation of Objective speckles calculations. Using MATLAB the image can be converted into binary object (0 and 1) as the speckle spots intensities are dark and bright, respectively.To simplify the calculations, two processes (transform and predictive) may be used, and according to the loss of many data for the using of predictive process, the transform process is considered.The calculations are based on the evaluation on small roughness of surfaces in range 0.1 – 1 μm, on the same footing the contrast was considered in the range from zero to one.Fraunhofer diffraction Unfortunately, no calculations in this field had been done from other researchers.

<p><strong><em>Begonia rigidifolia</em> ssp. <em>sonhungii</em> (sect. <em>Petermannia</em>, Begoniaceae), a new subspecies from limestone hills in Central Vietnam</strong></p>

Begonia rigidifolia Aver. ssp. sonhungii C.W.Lin (sect. Petermannia, Begoniaceae) from Central Vietnam is hereby described and illustrated as new. It resembles B. rigidifolia ssp. rigidifolia, but differs in its very sparsely puberulous (vs. glabrous), darker toned lamina that is embellished with a pale green broad band (vs. emerald green lamina with irregular radiantly arranged dark spots), stamens widely obovate (vs. obovate) and capsule with wider abaxial wing 6–10 mm (vs. 2–3 mm).

Postharvest senescent dark spot development mechanism of Musa acuminata ("Khai" banana) peel associated with chlorophyll degradation and stomata cell death.

The occurrence of the postharvest physiological disorder of dark spots on the peel of the ripened "Khai" banana has led to a reduction in its commercial value. The objective of the present study was to investigate the development mechanisms of senescence dark spots of the "Khai" (Musa AA group) banana peel in relation to chlorophyll degradation and stomata cell death. Freshly harvested bananas (commercial mature green stage) were let to ripened at 25±2°C (90%-95% RH). Peel color, senescent spots, DNA degradation, chlorophyll content, chlorophyll-degrading enzyme activities were assessed. The senescent dark spots developed on the ripened bananas right after 6days of storage, which coincided with remarkably increased DNA degradation, and a rapid decreased of hue angle value and total chlorophyll content which indicated the chlorophyll degradation. The activities of chlorophyllase, chlorophyll-degrading peroxidase and pheophytinase increased gradually to the highest point where the chlorophyll content drastically reduced and the appearance of the dark spots was first recorded after 6days of storage. These dark spots were observed to be surrounded with a bright luminescent ring of hypermodified fluorescent chlorophyll catabolites (FCCs), the product of chlorophyll breakdown. Additionally, the scanning electron microscope (SEM) revealed that the dark spots were found to have originated from the collapsed cells around the stomata of the ripened banana peel whereby the chlorophyll was entirely diminished. PRACTICAL APPLICATIONS: This research revealed the senescent dark spot development mechanisms of the "Khai" banana peel. The dark spot development symptom on the banana peel surface was caused by the senescence and cell death of the relevant stomata, further associated with chlorophyll degradation. Therefore, any further research into minimizing the dark spot symptom must focus on preventing or delaying stomata senescence and cell death.

Dark spot detection for characterization of marine surface slicks using UAVSAR quad-pol data

Oil spills are a potential hazard, causing the deaths of millions of aquatic animals and this leaves a calamitous effect on the marine ecosystem. This research focuses on evaluating the potential of polarimetric parameters in discriminating the oil slick from water and also possible thicker/thinner zones within the slick. For this purpose, L-band UAVSAR quad-pol data of the Gulf of Mexico region is exploited. A total number of 19 polarimetric parameters are examined to study their behavior and ability in distinguishing oil slick from water and its own less or more oil accumulated zones. The simulation of compact-pol data from UAVSAR quad-pol data is carried out which has shown good performance in detection and discrimination of oil slick from water. To know the extent of separation between oil and water classes, a statistical separability analysis is carried out. The outcomes of each polarimetric parameter from separability analysis are then quantified with the radial basis function (RBF) supervised Support Vector Machine classifier followed with an accurate estimation of the results. Moreover, a comparison of the achieved and estimated accuracy has shown a significant drop in accuracy values. It has been observed that the highest accuracy is given by LHV compact-pol decomposition and coherency matrix with a classification accuracy of ~ 94.09% and ~ 94.60%, respectively. The proposed methodology has performed well in discriminating the oil slick by utilizing UAVSAR dataset for both quad-pol and compact-pol simulation.

LINGUISTIC RELATIVITY: DOES LANGUAGE INFLUENCE THE PERCEPTION OF THE WORLD AND THE WAY WE THINK?

Language and perception have always been two controversial dilemmas in the cognitive system. The interaction between them has been studying not completely but partially throughout the years by linguists. From what we were able to discover, the linguistic and perceptual interactions in human being can explain a whole lot when it comes to comprehension of typical and atypical human behaviors. In this editorial, we thoroughly examine the language perception relationship. In conclusion, while there is compelling evidence to support an ultimate relationship between the linguistic and perceptual systems, the exact levels at which the two systems interact, the timing of the interaction, and what drives the interaction remain largely open remain another dark spot for future to lighten up.