Extreme Region Research Articles

Content-Aware Segmentation of Objects Spanning a Large Size Range: Application to Plankton Images

As the basis of oceanic food webs and a key component of the biological carbon pump, planktonic organisms play major roles in the oceans. Their study benefited from the development of in situ imaging instruments, which provide higher spatio-temporal resolution than previous tools. But these instruments collect huge quantities of images, the vast majority of which are of marine snow particles or imaging artifacts. Among them, the In Situ Ichthyoplankton Imaging System (ISIIS) samples the largest water volumes (> 100 L s-1) and thus produces particularly large datasets. To extract manageable amounts of ecological information from in situ images, we propose to focus on planktonic organisms early in the data processing pipeline: at the segmentation stage. We compared three segmentation methods, particularly for smaller targets, in which plankton represents less than 1% of the objects: (i) a traditional thresholding over the background, (ii) an object detector based on maximally stable extremal regions (MSER), and (iii) a content-aware object detector, based on a Convolutional Neural Network (CNN). These methods were assessed on a subset of ISIIS data collected in the Mediterranean Sea, from which a ground truth dataset of > 3,000 manually delineated organisms is extracted. The naive thresholding method captured 97.3% of those but produced ~340,000 segments, 99.1% of which were therefore not plankton (i.e. recall = 97.3%, precision = 0.9%). Combining thresholding with a CNN missed a few more planktonic organisms (recall = 91.8%) but the number of segments decreased 18-fold (precision increased to 16.3%). The MSER detector produced four times fewer segments than thresholding (precision = 3.5%), missed more organisms (recall = 85.4%), but was considerably faster. Because naive thresholding produces ~525,000 objects from 1 minute of ISIIS deployment, the more advanced segmentation methods significantly improve ISIIS data handling and ease the subsequent taxonomic classification of segmented objects. The cost in terms of recall is limited, particularly for the CNN object detector. These approaches are now standard in computer vision and could be applicable to other plankton imaging devices, the majority of which pose a data management problem.

Turbulence characteristics in a weir-orifice-slot combined fishway with an identical layout

A combined fishway containing notched weir, central orifice and vertical slot with an identical layout was designed, and its turbulence characteristics were experimentally studied. An acoustic Doppler velocimetry (ADV) was used to measure three-dimensional velocity. Flow regime, average velocity, turbulence intensity, Reynolds stress, power frequency-spectrum, correlation function, turbulence scale were analysed. The experimental results showed the combined fishway was of remarkable three-dimensional flow structures. Longitudinal velocity exhibited obvious extreme value region on the horizontal plane. Extreme values of longitudinal turbulence intensity were concentrated mainly on the mixing region between weir flow and orifice jet, as well as the vertical slot wall jet region, extreme value region of transverse turbulence intensity occurred on the central plane of orifice jet, and extreme values of vertical turbulence intensity were scattered. Reynolds stress extreme value occurred mainly in the convergent zone of multiple jets. Dominant frequency of power frequency-spectrum was highest for notched weir and lowest for vertical slot. Longitudinal velocity fluctuation exhibited a correlation with time, which was characterised by dominant frequency. Turbulence scales showed eddy structures were related to flow zones.

Contribution of the Sn 5s state to the SnS valence band: direct observation via ARPES measurements

Tin sulfide (SnS) is a compound semiconductor that has been studied for a wide range of applications, including solar cells and thermoelectric materials. In this study, the electronic structure of the SnS valence band, which is important for such applications, was investigated via angle-resolved photoelectron spectroscopy with two different excitation energies in the extreme ultraviolet region (21 and 60 eV). The contribution of the Sn 5s state to the SnS valence band was determined in relation to the k-vector by utilizing the fact that the cross section of Sn 5s state varies significantly compared to those of other states in the extreme ultraviolet region. The experimental results demonstrate that the Sn 5s state significantly contributed to the k-vector around the valence band maximum (VBM) and second VBM (VBM1).

September 2017 Solar Flares Effect on the Middle Atmosphere

This paper examines the response of the upper atmosphere to increased radiation following exceptional solar activity in September 2017. The active region of the Sun AR2673 has caused intense solar-terrestrial disturbance. This active region has generated several powerful X-class solar flares. The strongest outburst of the 24th solar activity cycle X9.3 occurred on 6 September 2017. The second powerful solar flare X8.2 occurred on 10 September 2017. Both flares caused an increase of the solar irradiance in extreme ultraviolet and soft X-ray spectral regions, and Ly-α line. The empirical FISM2 model was used to obtain data on the radiation fluxes from solar flares. The HAMMONIA chemistry–climate model was used to analyze the effect of radiation on the neutral atmosphere. This work presents the results of the effect of solar flares on the chemical composition and ozone of the upper and middle atmosphere.

Pulmonary Embolism at Extreme High Altitude: A Study of Seven Cases.

Wu, Jialin, Xiaobo Han, Haiwen Ke, Li Wang, Kun Wang, Jianli Zhang, Jun Tang, Wei Yan, Guangjun Wang, and Peng Jiang. Pulmonary embolism at extreme high altitude: A study of seven cases. High Alt Med Biol. 23:209-214, 2022. Background: The incidence of venous thromboembolism (VTE) is high in high-altitude (HA) areas. We analyzed cases of pulmonary embolism (PE) in extreme HA areas to explore the epidemiological characteristics and risk factors of PE in these regions. Methods: Seven cases of PE occurring in an extreme HA region were prospectively collected at an HA (3,800 m) hospital from May to November 2020. All patients resided 5,000 m above sea level and were diagnosed with PE using computed tomography pulmonary angiography. Results: Seven patients (24 ± 3.6 years old) had symptom onset at a mean altitude of 5,200 ± 200 m, and the duration spent at HA ranged from 8 to 210 days (99.29 ± 77.31 days). Cough, expectoration, chest tightness, fever, shortness of breath, and chest pain were the most common symptoms. Six of the seven patients were initially diagnosed with pulmonary inflammation, and four were diagnosed with high-altitude pulmonary edema using computed tomography or X-ray. Most patients presented with an increased concentration of inflammatory cells and high initial D-dimer levels. Conclusions: In this study, a retrospective analysis of PE case data in extreme HA areas suggested that PE was underdiagnosed owing to misdiagnosis or masking by HA-associated disease.

Natural scene text detection and recognition based on saturation-incorporated multi-channel MSER

The detection and recognition of natural scene text is a crucial computer task for the automatic identification and classification of industrial resources with words or labels, and it has gained much attention recently because of its potential to boost production efficiency. Maximally Stable Extremal Region (MSER) is an effective detection method for the natural scene text. However, MSER and its variants have not adequately considered the color information like Red, Green, and Blue (RGB). To address this problem, we present a combined detection method by Canny edge detector focusing on the edge and the improved multi-channel MSER concentrating on the area, where the channels incorporated into MSER consist of R, G, and B channels of the RGB color space and the S channel of the Hue, Saturation and Intensity (HSI) color space. Such a multi-channel MSER method takes full consideration of the color information into the text detection without causing a significant increase in the computational cost. In addition, a text recognition system is presented on the basis of the proposed text detection method. The proposed method for text detection and recognition is evaluated on three datasets including the ICDAR2013, the ICDAR2015, and the ICDAR2017-MLT. Experimental results show that our method outperforms the state-of-the-art methods with the highest Precision of 89.4%, Recall of 93.7%, F-score of 91.5%, and about the shortest runtime of 0.76s on an image of 512 × 512 pixels.

Illustrating the physics of core tungsten (W) transport in a long-pulse steady-state H-mode discharge on EAST

The behavior of core tungsten (W) in a pure radio-frequency-heated long-pulse steady-state H-mode discharge in the Experimental Advanced Superconducting Tokamak (EAST) with an ITER-like divertor (ILD) is analyzed using experimental diagnostic data and modeled using a combination of drift-kinetic neoclassical and gyro-fluid turbulent software. In the steady state, the experimental core line-averaged W concentration (C W) is about 2 × 10−5, which is evaluated using the intensity of the W unresolved transition array (W-UTA) spectral structure in the region of 45–70 Å (which is composed of W 27+–W 45+ line emissions) through spectroscopy in the extreme ultraviolet region. W produces a peak of the radiated power density profile around a normalized radius of ρ ∼ 0.3. Therefore, W does not centrally accumulate in the experiment. A time slice of the steady-state is modeled, which accounts for both the neoclassical and turbulent transport components of W based on the self-consistent background plasma profiles simulated by TGYRO (Candy et al 2009 Phys. Plasmas 16 060704). It is found that turbulent transport dominates over neoclassical transport for W. In addition, the turbulent diffusion coefficient is large enough to offset the sum of the neoclassical and turbulent pinch (convection) velocities, so that the W density profile for a zero particle flux is not strongly peaked. By combining TGLF (Staebler et al 2017 Nucl. Fusion 57 066046) and NEO (Belli and Candy 2008 Plasma Phys. Control. Fusion 50 095010; 2012 Plasma Phys. Control. Fusion 54 015015) for the W transport coefficient with the impurity transport code STRAHL (Dux 2006 STRAHL User Manual), the experimental C W and the information radiated by W can be reproduced closely. In addition, the effect of toroidal rotation on the W transport is also clarified.

Radical-based extract and recognition networks for Oracle character recognition

AbstractThe recognition of Oracle bone inscription (OBI) is one of the most fundamental aspect of OBI study. However, the complex glyph structure and many variants of OBI, which hinder the advancement of automatic recognition research. In order to solve these problems, this paper designs an Oracle radical extract and recognition framework(ORERF) based on deep learning. First, combining the maximally stable extremal regions(MSER) algorithm and self-defined post-processing algorithm to generate Oracle single radical data annotation; then, the generated Oracle radical-level annotation data set is input into the detection network, the detection network integrates multi-scale features, and uses the attention mechanism to implicitly extract Oracle single radical features, and then feeds the feature map to the detection module for radical detection; finally, we put the detected radicals to the auxiliary classifier network for recognition. The method of treating an OBI character as a composition of radicals rather than as a character category is a human-like method that can reduce the size of the vocabulary, ignore redundant information among similar characters. The experimental results are highlighted and compared to demonstrate the efficiency of the method. Furthermore, we also introduce two new datasets containing Oracle radical character dataset(ORCD) and Oracle combined-character dataset(OCCD).

Der ‚lange Atem‘ der bäuerlichen Empörung

The Persistence of Peasant Outrage. Conflicts over Forest Use, Poaching and Fraternity Revolts in the Zillertal from the 16th to the End of the 18th Century When I tried to follow the traces of Salzburg poachers in the 18th century more than twenty years ago, I was not aware of how deeply rooted their social protest was in earlier, less spectacular but much more widespread forest conflicts between peasants and the archepiscopal state. Of course, these were different conflicts fought by different opponents, but they aimed at the same goal: to resist increasing restrictions from a bureaucratic state whose existence brought the peasants no benefits. The inhabitants of this extreme mountain region wanted to remain autonomous in their traditional economical and social practices and resisted the introduction of a forest economy by a state that was unable and unwilling to support and compromise with them. Thus, the remote forests, whose economic use was in many ways legally unclear, became the centre of social conflict. The article reconstructs two protest traditions – that of illegal forest use and that of poaching – in a micro-historical analysis of the situation in the Zillertal. It argues that the intermingling of these traditions ultimately created an Alpine protest culture in the minds and memories of the peasantry that was stable and persistent enough to undermine the episcopal state during the Napoleonic wars.

Der ‚lange Atem‘ der bäuerlichen Empörung

The Persistence of Peasant Outrage. Conflicts over Forest Use, Poaching and Fraternity Revolts in the Zillertal from the 16th to the End of the 18th Century When I tried to follow the traces of Salzburg poachers in the 18th century more than twenty years ago, I was not aware of how deeply rooted their social protest was in earlier, less spectacular but much more widespread forest conflicts between peasants and the archepiscopal state. Of course, these were different conflicts fought by different opponents, but they aimed at the same goal: to resist increasing restrictions from a bureaucratic state whose existence brought the peasants no benefits. The inhabitants of this extreme mountain region wanted to remain autonomous in their traditional economical and social practices and resisted the introduction of a forest economy by a state that was unable and unwilling to support and compromise with them. Thus, the remote forests, whose economic use was in many ways legally unclear, became the centre of social conflict. The article reconstructs two protest traditions – that of illegal forest use and that of poaching – in a micro-historical analysis of the situation in the Zillertal. It argues that the intermingling of these traditions ultimately created an Alpine protest culture in the minds and memories of the peasantry that was stable and persistent enough to undermine the episcopal state during the Napoleonic wars.

The Witch in the Closet: Disney's Frozen as Adaptation and Its Potential for Queer and Feminist Readings

The Witch in the Closet: Disney's <i>Frozen</i> as Adaptation and Its Potential for Queer and Feminist Readings

High Photon Number Entangled States and Coherent State Superposition from the Extreme Ultraviolet to the Far Infrared.

We present a theoretical demonstration on the generation of entangled coherent states and of coherent state superpositions, with photon numbers and frequencies orders of magnitude higher than those provided by the current technology. This is achieved by utilizing a quantum mechanical multimode description of the single- and two-color intense laser field driven process of high harmonic generation in atoms. It is found that all field modes involved in the high harmonic generation process are entangled, and upon performing a quantum operation, lead to the generation of high photon number optical cat states spanning from the far infrared to the extreme ultraviolet spectral region. This provides direct insights into the quantum mechanical properties of the optical field in the intense laser matter interaction. Finally, these states can be considered as a new resource for fundamental tests of quantum theory, quantum information processing, or sensing with nonclassical states of light.

Quantum Sensing with Extreme Light

AbstractOptical nonlinear conversion processes are ubiquitously applied to scientific as well as industrial tasks. In particular, nonlinear processes are employed to generate radiation in many frequency ranges. In plenty of these nonlinear processes, the generation of paired photons occurs — the so‐called signal and idler photons. Although this type of generation has undergone a tremendous development over the last decades, either the generated signal or the idler radiation has been used experimentally. In contrast, novel quantum‐based measurement principles enable the usage of both partners of the generated photon pairs based on their correlation. These measurement approaches have an enormous potential for future applications, as they allow to transfer information from one spectral range to another. In particular, spectral ranges where photon generation and detection is particularly challenging can benefit from this principle. Above all, these include the extreme frequency ranges, such as on the low‐frequency side the mid to far infrared or even the terahertz spectral range, but also on the high‐frequency side the ultraviolet or X‐ray spectral range. In this review article, theoretical and experimental developments based on correlated biphotons are described specifically for the extreme spectral regions.

Modification of the N-terminal FWKG-αH1 element of potyviral HC-Pro affects its multiple functions and generates effective attenuated mutants for cross-protection.

Control of plant viruses by cross‐protection is limited by the availability of effective protective strains. Incorporation of an NIa‐protease processing site in the extreme N‐terminal region of the helper component protease (HC‐Pro) of turnip mosaic virus (TuMV) resulted in a mutant virus TuHNDI that induced highly attenuated symptoms. Recombination analysis verified that two variations, F7I mutation and amino acid 7‐upstream‐deletion, in HC‐Pro co‐determined TuHNDI attenuation. TuHNDI provided complete protection to Nicotiana benthamiana and Brassica campestris subsp. chinensis plants against infection by the severe parental strain. Aphid transmission tests revealed that TuHNDI was not aphid‐transmissible. An RNA silencing suppression (RSS) assay by agroinfiltration suggested the RSS‐defective nature of the mutant HC‐Pro. In the context (amino acids 3–17) encompassing the two variations of HC‐Pro, we uncovered an FWKG−α‐helix 1 (αH1) element that influenced the functions of aphid transmission and RSS, whose motifs were located far downstream. We further demonstrated that HC‐Pro F7 was a critical residue on αH1 for HC‐Pro functions and that reinstating αH1 in the RSS‐defective HC‐Pro of TuHNDI restored the protein's RSS function. Yeast two‐hybrid and bimolecular fluorescence complementation assays indicated the FWKG−αH1 element as an integral part of the HC‐Pro self‐interaction domain. The possibility of regulation of the mechanistically independent functions of RSS and aphid transmission by the FWKG−αH1 element is discussed. Extension of TuMV HC‐Pro FWKG−αH1 variations to another potyvirus, zucchini yellow mosaic virus, also generated nonaphid‐transmissible cross‐protective mutant viruses. Hence, the modification of the FWKG−αH1 element can generate effective attenuated viruses for the control of potyviruses by cross‐protection.

Segmentation of intravascular ultrasound images based on convex–concave adjustment in extreme regions

Segmentation of intravascular ultrasound images based on convex–concave adjustment in extreme regions

High spatial-resolution loss estimation using dense array strong-motion near-fault records. Case study for Hveragerði and the [formula omitted]6.3 Ölfus earthquake, South Iceland

The most recent and costliest damaging earthquake in Iceland is the Mw6.3 29-May-2008 Ölfus earthquake to date. In particular, Hveragerði town located in the extreme near-fault region, suffered intense horizontal peak ground accelerations (PGA) of ∼ 40–90%g and large amplitude and long-period near-fault pulses, recorded on a dense urban strong-motion array in the town. In this study we collated a high-spatial resolution exposure database (building-by-building) complete with actual reported losses and classified the buildings by building materials and construction year according to the code design requirements in place at the time.We took advantage of the array data and evaluated a set of well-known ground motion intensity measures (IM), including PGA, pseudo-acceleration response spectra at short-to-long periods, Arias Intensity and Cumulative Absolute Velocity. We applied empirical Bayesian kriging geostatistical analyses to generate high-resolution shakemaps and provide IM estimates for each building. The shakemaps showed a significant and systematic variation of the IMs across the small study area, with the lowest ground motions observed centrally and highest values in the outskirts. Furthermore, correlation analysis was carried out for the damage ratio and the exposure data IMs, but only low-to-moderate correlations were observed. A key reason is the incurred losses were primarily due to damage to non-structural components, to which the code design requirements do not apply. We carried out a seismic loss assessment in Hveragerði for the earthquake scenario of the Ölfus earthquake both on building-by-building, and municipality levels of spatial resolution. We applied both local and global fragility models associated with detail building typologies identified based on the SERA taxonomy scheme.The results show that the global fragility functions severely underestimate the seismic performance of the building stock, except for one-story reinforced concrete buildings, while overall the masonry buildings were associated with the most predicted and observed losses. On the other hand, the local models predicted losses that conformed well with the observed damages to timber and concrete buildings. The high-spatial-resolution predictions of losses gave results that better correlated with the observed losses in most typologies.

First principles prediction of the stable MgFCl Janus monolayer with tunable properties

Herein, we introduce a new Janus monolayer, namely MgFCl, where its structural, electronic, and optical properties are systematically investigated by means of first-principles calculations. It is demonstrated that MgFCl single layer is structurally and dynamically stable. The electronic band structure indicates a wide Γ − Γ direct gap of 4.32(5.61) eV as determined by PBE(HSE06) functional. Consequently it exhibits a good absorption in the far and extreme ultraviolet region. In addition, the physical properties tuning via external strain and alkaline earths substitution is also studied. Results show a strong strain-dependence of the energy gap, however the direct gap nature is retained. The alkaline earths incorporation induces a strong structural local distortion due to the atomic size difference. A band gap reduction of 0.19 eV is caused by Ca atom, while the Sr and Ba atoms induce insignificant change of this important parameter. Calculated spectra suggest that the MgFCl monolayer absorption may be extended to a wider energy range and enhanced by applying proper strain and alloying. Results presented herein may recommend new two-dimensional (2D) materials for applications in optoelectronic nano devices, specifically, those working under high energy conditions. • MgFCl Janus monolayer exhibits good stability. • MgFCl Janus monolayer is a direct gap insulator with band gap of 5.61 eV. • The external strain can tune effectively the electronic structure. • Ca incorporation reduces the energy gap, while Sr and Ba presence induces insignificant change. • Optical properties of MgFCl monolayer can be enhanced by either external strains or alkaline earth substitution.

A Text Location Method for Sign Based on Pixel-level Gradient Ray Images and Edge Contour Mapping

Compared with deep learning methods, traditional image processing methods have lower computational costs and have advantages for typical problems such as sign text, this paper proposes a sign text location method based on pixel-level gradient ray map and edge contour mapping. First, based on image pre-processing, the pixel-level gradient ray map is obtained by using the Stroke Width Transform. Then, using the Maximally Stable Extremal Region method to locate the irregular text candidate area in the ray map. At the same time, add a mask layer to filter the irregular candidate area, and then regularize the candidate area and perform Non-Maximum Suppression processing. Finally, the background non-text candidate area is processed by extracting the mapping of the closed edge contour of the image, and the remaining text area positioning candidate frame coordinates are mapped back to the original picture. The experimental results show that the method is simple and clear, the effect is remarkable, and it has good robustness to the sign of different sizes.

Experimental study on a new type of precast beam-column joint

In this study, a new type of dry-connection precast beam-column joint is proposed. The dry connection is easy to assemble, which can greatly reduce the labor intensity of the construction site. At the same time, it is easy to disassemble, which is conducive to the upgrading of components and the replacement of seismic damaged components during the lifetime of the building. It is conducive to the industrialization and seismic resilience of the building. It is suitable for the construction in extreme cold climate and high seismic intensity regions. In order to evaluate the seismic performance of the dry connection, a precast joint model and a cast-in-situ joint model were constructed, and pseudo-static tests were carried out. The test results show that the bearing capacity of the precast joint is approximately equal to the cast-in-situ joint. The failure mode of the precast joint satisfies the principle of strong column and weak beam, and beam damage is concentrated on the steel connectors. Finally, the finite element model of the precast joint is established, and the analysis results show that it can well simulate the mechanical behavior of the joint.

Comparison of Rumen Fermentation Parameters and Microbiota of Yaks From Different Altitude Regions in Tibet, China.

Rumen microbiota are closely linked to feed utilization and environmental adaptability of ruminants. At present, little is known about the influence of different extreme environments on the rumen microbiota of yaks. In this study, 30 ruminal fluid samples from 30 healthy female yaks (average 280 kg of BW) in 5–8 years of life were collected from three regions in Tibet, China, and compared by gas chromatography and high-throughput sequencing. Results showed that propionic acid, butyric acid, and total volatile fatty acids were significantly (p < 0.05) higher, while microbial abundance and diversity were significantly (p < 0.05) lower, in the Nagqu (4,500 m altitude) compared with the Xigatse (4,800 m altitude) and Lhasa (3,800 m altitude) regions. Principal coordinate analysis revealed significant (p < 0.05) differences in rumen microbial composition of yaks from different regions. Specifically, Bacteroidetes and Firmicutes were identified by linear discriminant analysis effect size (LDA > 3) as being the signature phyla for Xigatse and Nagqu regions, respectively. In addition, the relative abundance of Rikenellaceae_RC9_gut_group, Quinella, Prevotellaceae_UCG-003, Lachnospiraceae_NK3A20_group, Papillibacter, Ruminococcaceae_UCG-010, Prevotellaceae_NK3B31_group, and Ruminococcaceae_UCG-005 correlated with altitude and rumen fermentation parameters (p < 0.05). Finally, the predicted function of rumen microbiota was found to differ between regions (p < 0.05). In summary, our results reveal that regions located at different altitudes influence microbiota composition and fermentation function of yaks’ rumen. The present findings can provide mechanistic insights on yak adaptation to high altitudes and improve the feeding efficiency of these animals in extreme regions.