Structural Mapping Research Articles

Detailed mapping of the complex fiber structure and white matter pathways of the chimpanzee brain

Long-standing questions about human brain evolution may only be resolved through comparisons with close living evolutionary relatives, such as chimpanzees. This applies in particular to structural white matter (WM) connectivity, which continuously expanded throughout evolution. However, due to legal restrictions on chimpanzee research, neuroscience research currently relies largely on data with limited detail or on comparisons with evolutionarily distant monkeys. Here, we present a detailed magnetic resonance imaging resource to study structural WM connectivity in the chimpanzee. This open-access resource contains (1) WM reconstructions of a postmortem chimpanzee brain, using the highest-quality diffusion magnetic resonance imaging data yet acquired from great apes; (2) an optimized and validated method for high-quality fiber orientation reconstructions; and (3) major fiber tract segmentations for cross-species morphological comparisons. This dataset enabled us to identify phylogenetically relevant details of the chimpanzee connectome, and we anticipate that it will substantially contribute to understanding human brain evolution.

Probabilistic Determination of the Role of Faults and Intrusions in Helium‐Rich Gas Fields Formation

AbstractNatural gas fields with economic helium (>0.3 He %) require the radioactive decay of crustal uranium (U) and thorium (Th) to generate He and tectonic/structural regimes favorable to releasing and concentrating He. An unknown is determining the role of faults and structural features in focusing deep‐seated He sources on shallow accumulations. We tested the correlation between high‐He wells (n = 94) and structural features using a new high‐resolution aeromagnetic survey in the Four Corners area, USA. A depth‐to‐basement map with basement lineaments/faults, an intrusion map, and a flattened basement structural high map were created using Werner deconvolution algorithms by combining magnetic, gravity, and topography data with magnetic and gravity depth profiles. We show quantitatively (via analysis of variance) that a non‐random process controls the relationship between He (>0.3%) and both basement faults and intrusions: 88% of high‐He wells occur <1 km of basement faults; and 85% of high‐He wells occur <1 km of intrusions. As He % increases, the distance to the structural features decreases. Strong spatial/statistical correlations of He wells to both basement faults and intrusions suggest that advective transport via faults/intrusions facilitates He migration. The role of gas phase buoyancy and structural trapping is confirmed: 88% of high‐He occurs within basement structural highs, and 91% of the remaining wells are <1 km from intrusions (potential structural high). We present a composite figure to illustrate how a probabilistic approach can be used as a predictive model to improve He exploration success by targeting zones of intersection of basement faults and intrusions within basement structural highs.

From Material Cadastres to a Materiality Informed City Information Modelling

Abstract Urbanization and built environment significantly impact resource consumption, posing sustainability challenges, especially regionally, due to bulk material dominance. Circular practices, like closing, slowing, and narrowing offer solutions. However, effective circularity management requires understanding built environment material stock comprehensively. Material cadastres model city and regional materiality using typology approaches and GIS Modelling, offering insights into circularity potential and supporting strategic circular city management. Conversely, urban planning digitalization introduced City Information Modelling, linking GIS for urban structure mapping with Building Information Modelling systems for digital building integration and thus support urban planning. Yet, empirically, materiality and circularity issues lack systematic and comprehensive integration in such approaches. To this end, this paper discusses the potential of developing digital material cadastre concepts towards materiality-based urban information modelling using case study results that reveal strengths and limitations of existing cadastre concepts. We present a methodological overview covering a general approach to built environment material cadastres and the main components of the underlying bottom up Material Flow approach: material composition indicators and GIS based building stock modelling and a dynamization approach. To discuss circularity potentials of the built environment in a larger urban regional development context, we furthermore designed material cadastres for two case study cities and calculated exemplary circularity potentials for closing, slowing and narrowing approaches. The findings and drafted conclusions were then reflected with urban planning and development actors in workshops and group discussions. As a result, we present consolidated propositions with respect to bridging the methodological gap between strategic and operational materiality informed urban and regional planning in the transition of the built environment towards circularity.

Association mapping of septoria tritici blotch resistance in bread wheat in Bale and Arsi highlands, Ethiopia

Septoria tritici blotch (STB) caused by the fungal pathogen Zymoseptoria tritici, anamorph Septoria tritici Rob. ex Desm., is an important wheat pathogen worldwide, reported to be major wheat production threating factor, posing considerable yield loss every year. Developing resistant cultivars is an efficient, economical, environmentally friendly and simple approach for managing STB. This study was carried out to evaluate spring bread wheat lines for their reaction to STB disease under field conditions; to associate phenotypic and genotypic data for identification of STB disease resistance; and to identify genomic region(s) associated with resistance to STB in spring bread wheat lines. Two hundred forty (240) spring bread wheat lines were evaluated under field conditions in non-replicated trials, using an augmented design. The trials were conducted at three locations (Kulumsa Agricultural Research Center, Madda Walabu University Research Site and Sinana Agricultural Research Center) in 2017 main cropping season (July to December). Out of these 240 wheat lines, 123 of them were genotyped with 10263 single nucleotide polymorphism (SNPs) markers and population structure and association mapping analysis was done. The wheat lines showed significant variations in percentage disease severity and area under the disease progress curve at all the three locations they were evaluated. The wheat lines were classified as resistant, moderately resistant, moderately susceptible and susceptible based on the percentage disease severity scored. Five wheat lines were found to be resistant to STB in all the three locations and are recommended for direct release by the national program and parentage purposes in wheat breeding programs. The 123 wheat lines were clustered into 3 subpopulations in which the first cluster contained 99 wheat lines; the second 17 and the last one 7. Among the polymorphic 8127 SNPs markers, 26 markers on chromosomes 7B, 1D, 3A, 2B, 6B and 3D were found to be significantly (P < 0.001) associated with STB resistance so that they can be utilized for marker assisted selection and gene pyramiding in resistance breeding programs.

Evidence and concerns about a latent, embryonic phase tectonic evolution and the existence of the young subsurface ocean on Mimas

The icy moons of outer Solar system gas and ice giants have been in the spotlight of scientific and common interest because of the possibility of a subsurface ocean hidden under their ice shells, which may harbor extraterrestrial life. The patterns of various lineaments on the surface of icy satellites may indicate active tectonic processes and the interaction between the surface and the subsurface ocean, which allows material transport toward the habitat of putative alien life. In the case of Mimas, one of the moons of Saturn, new models challenge the long-standing conclusion about the satellite being an inactive snowball, suggesting the existence of a young ocean hiding under its ice shell. Unfortunately, no observable evidence has been found implying ongoing or probably already stopped tectonic activity and the theoretical subsurface ocean. Here, we present the first structural geological map of the icy satellite, with the signs of various tectonic features, along with a simple crosscutting chronology of lineaments formation. In accordance with the theoretical young age of the subsurface ocean, the observed phenomena are described as putative lineaments, ridges, and troughs. Such simple tectonic features are identified as young compared to complex structures, such as bands appearing on other satellites. The pattern of the linear features seems to overlap with the allocation of various modeled global nonlinear tidal dissipation patterns. In such a way, it may indicate the possible existence of the theoretical subsurface stealth ocean. With such an evolving young subsurface ocean and the barely recognizable pattern of simple lineaments, Mimas may represent a newly recognized group of icy satellites showing the early, latent, embryonic phase of tectonic activity. In contrast, the overlapping and crosscutting relations between craters and the observed features may raise some concerns about the “recent” formation of such linear features, indicating possibly long-time dormant or already stopped tectonic processes at the very early, embryonic phase of lineament formation billions of years ago. Despite the possible additional triggers of tectonic processes on icy satellites (e.g., surface crust mobility by plastic subsurface deformation), the presented geological investigation brought a new angle and additional evidence about a possible stealth ocean hiding under the crater-covered surface of Mimas, regardless of its geological age and recent state of evolution. Undoubtedly, the results and the raised concerns will trigger more intense investigations on Mimas and other, similar icy satellites in the Solar system.

Discovery flows from mapping for conservation planning: the case of finding and mapping of Second World War British Hong Kong defence structures

This article develops MacEachren’s summary of contemporary approaches to cartography as communication as a one-way flow of map information. The Hong Kong experience shows that large-scale government survey maps can be used by non-specialists to (re)discover and identify, for conservation planning purposes, very small Second World War defence structures not annotated on those maps. By accumulating information and field studies, non-specialists can produce specialist maps as a contribution to conservation planning. The issues of a market for military heritage buildings and the actual role the government cartographer played in conservation mapping are discussed.

Second-Generation Chiral Amino Acid Derivatives Afford High Stereoselectivity and Stability in Aqueous RNA Acylation.

Activated acyl species have proven versatile in the esterification of 2'-OH groups in RNA, enabling structure mapping, caging, profiling, and labeling of the biopolymer. Nearly all reagents developed for this reaction have been achiral; however, a recent study reported that simple chiral amino acid acylimidazole derivatives could yield diastereoselective reactions at RNA 2'-OH in water, enabling up to 4:1 selectivity in screening. Here, we investigated the effect of steric bulk on the stereoselectivity of RNA reaction and on the stability of adducts with a library of 36 chiral acylimidazole scaffolds with increasing steric demand. The results document the highest stereoselectivity yet achieved in RNA acylation reactions, with as high as >99:1 diastereoselectivity at >70% conversion. Also notably, the bulky adducts were found to have markedly improved stability on RNA.

Optimizing NMR fragment-based drug screening for membrane protein targets

NMR spectroscopy has played a pivotal role in fragment-based drug discovery by coupling detection of weak ligand-target binding with structural mapping of the binding site. Fragment-based screening by NMR has been successfully applied to many soluble protein targets, but only to a limited number of membrane proteins, despite the fact that many drug targets are membrane proteins. This is partly because of difficulties preparing membrane proteins for NMR—especially human membrane proteins—and because of the inherent complexity associated with solution NMR spectroscopy on membrane protein samples, which require the inclusion of membrane-mimetic agents such as micelles, nanodiscs, or bicelles. Here, we developed a generalizable protocol for fragment-based screening of membrane proteins using NMR. We employed two human membrane protein targets, both in fully protonated detergent micelles: the single-pass C-terminal domain of the amyloid precursor protein, C99, and the tetraspan peripheral myelin protein 22 (PMP22). For both we determined the optimal NMR acquisition parameters, protein concentration, protein-to-micelle ratio, and upper limit to the concentration of D6-DMSO in screening samples. Furthermore, we conducted preliminary screens of a plate-format molecular fragment mixture library using our optimized conditions and were able to identify hit compounds that selectively bound to the respective target proteins. It is hoped that the approaches presented here will be useful in complementing existing methods for discovering lead compounds that target membrane proteins.

Structural heterogeneity predicts ecological resistance and resilience to wildfire in arid shrublands

ContextDynamic feedbacks between physical structure and ecological function drive ecosystem productivity, resilience, and biodiversity maintenance. Detailed maps of canopy structure enable comprehensive evaluations of structure–function relationships. However, these relationships are scale-dependent, and identifying relevant spatial scales to link structure to function remains challenging.ObjectivesWe identified optimal scales to relate structure heterogeneity to ecological resistance, measured as the impacts of wildfire on canopy structure, and ecological resilience, measured as native shrub recruitment. We further investigated whether structural heterogeneity can aid spatial predictions of shrub recruitment.MethodsUsing high-resolution imagery from unoccupied aerial systems (UAS), we mapped structural heterogeneity across ten semi-arid landscapes, undergoing a disturbance-mediated regime shift from native shrubland to dominance by invasive annual grasses. We then applied wavelet analysis to decompose structural heterogeneity into discrete scales and related these scales to ecological metrics of resilience and resistance.ResultsWe found strong indicators of scale dependence in the tested relationships. Wildfire effects were most prominent at a single scale of structural heterogeneity (2.34 m), while the abundance of shrub recruits was sensitive to structural heterogeneity at a range of scales, from 0.07 – 2.34 m. Structural heterogeneity enabled out-of-site predictions of shrub recruitment (R2 = 0.55). The best-performing predictive model included structural heterogeneity metrics across multiple scales.ConclusionsOur results demonstrate that identifying structure–function relationships requires analyses that explicitly account for spatial scale. As high-resolution imagery enables spatially extensive maps of canopy heterogeneity, models for scale dependence will aid our understanding of resilience mechanisms in imperiled arid ecosystems.

Tectonic inversion of an intracontinental rift basin: An example from the opening and closure of the Paleo-Tethys Ocean, northern Tibetan Plateau

Suture zones located across the Tibetan region clearly demarcate the rift-and-drift and continental accretion history of the region. However, the intraplate responses to these marginal plate-tectonic events are rarely quantified. Our understanding of the Paleo-Tethyan orogenic system, which involved ocean opening and closing events to grow the central Asian continent, depends on the tectonic architecture and histories of major late Paleozoic−early Mesozoic orogenic belts. These opening and collision events were associated with coupled intracontinental deformation, which has been difficult to resolve due to subsequent overprinting deformation. The late Paleozoic−early Mesozoic Zongwulong Shan−Qinghai Nanshan belt in northern Tibet separates the Qilian and North Qaidam regions and is composed of Carboniferous−Triassic sedimentary materials and mantle-derived magmatic rocks. The tectonic setting and evolutional history of this belt provide important insight into the paleogeographic and tectonic relationships of the Paleo-Tethyan orogenic system located ∼200 km to the south. In this study, we integrated new and previous geological observations, detailed structural mapping, and zircon U-Pb geochronology data from the Zongwulong Shan−Qinghai Nanshan to document a complete tectonic inversion cycle from intraplate rifting to intracontinental shortening associated with the opening and closing of the Paleo-Tethyan Ocean. Carboniferous−Permian strata in the Zongwulong Shan were deposited in an intracontinental rift basin and sourced from both the north and the south. At the end of the Early−Middle Triassic, foreland molasse strata were deposited in the southern part of the Zongwulong Shan during tectonic inversion in the western part of the tectonic belt following the onset of regional contraction deformation. The Zongwulong Shan−Qinghai Nanshan system has experienced polyphase deformation since the late Paleozoic, including: (1) early Carboniferous intracontinental extension and (2) Early−Middle Triassic tectonic inversion involving reactivation of older normal faults as thrusts and folding of pre- and synrift strata. We interpret that the Zongwulong Shan−Qinghai Nanshan initiated as a Carboniferous−Early Triassic intracontinental rift basin related to the opening of the Paleo-Tethyan Ocean to the south, and it was then inverted during the Early−Middle Triassic closing of the Paleo-Tethyan Ocean. This work emphasizes that pre-Cenozoic intraplate structures related to the opening and closing of ocean basins in the Tethyan realm may be underappreciated across Tibet.

Forest Structure Mapping of Boreal Coniferous Forests Using Multi-Source Remote Sensing Data

Modeling forest structure using multi-source satellite data is beneficial to understanding the relationship between vertical and horizontal structure and image features to provide more comprehensive and abundant information for the study of forest structural complexity. This study investigates and models forest structure as a multivariate structure based on sample data and active-passive remote sensing data (Landsat8, Sentinel-2A, and ALOS-2 PALSAR) from the Saihanba Forest in Hebei Province, Northern China, to measure forest structural complexity, relying on a relationship-driven model between field and satellite data. In this study, we considered the effects of the role of satellite variables in different vertical structure types and horizontal structure ranges, used two methods to stepwise select significant variables (stepwise forward selection and Pearson correlation coefficient), and employed a multivariate modeling technique (redundancy analysis) to derive a forest composite structure index (FSI), combining both horizontal and vertical structure attributes. The results show that optical texture can better represent forest structure characteristics, polarization interferometric radar information can represent the vertical structure information of forests, and combining the two can represent 77% of the variance of multiple forest structural attributes. The new FSI can explain 93% of the relationship between stand structure and satellite variables, and the linear fit R2 to the measured data reaches 0.91, which largely shows the situation of the measured data. The generated forest structure map more accurately reflects the complexity of the forest structure in the Saihanba Forest, achieving a supplementary explanation of the measured data.

Co-designing restrictive practice elimination: A systems thinking approach with mental health service users and practitioners in rural/regional Australia.

Elimination of restrictive practices (physical/mechanical restraint and seclusion) from adult acute mental health care services has been demanded internationally for many decades. This study aimed to: (1) Identify priority issues in the elimination of and use of alternative approaches to restrictive practices (seclusion and physical/mechanical restraint) in rural/regional acute adult mental healthcare services, as told by mental healthcare service users and practitioners, (2) identify the community-based, system-level feedback loops that enhance or reduce the use of restrictive practices and viable alternatives and, (3) identify potential action areas to improve system structures to increase regional mental healthcare services' ability to eliminate restrictive practices and use alternative approaches. Group model building (GMB) workshops were held with a small group (n = 9) of mental healthcare practitioners and service users with lived experience of restrictive practice use. This participatory approach enables exploration and visual mapping of local structures causing behaviour patterns of practitioner and service user concern over time - in this case, the barriers, and enablers to alternative approaches to restrictive practices in adult acute mental healthcare services within the Geelong-Barwon region. This is the first study that specifically applies GMB in the discussion of the elimination of restrictive practices in mental health in the non-metropolitan regional/rural context. Participants identified four key priorities in relation to eliminating restrictive practices: (1) self-advocacy, (2) continuity of care, (3) early intervention, and (4) safety for all. The study findings were distilled into a novel preliminary set of mental healthcare practitioner and service user action ideas.

Building a carbon dioxide storage portfolio for the Barrow-Dampier sub-basins through regional screening – an integrated geoscience approach

Safe geological carbon dioxide (CO2) storage (GCS) requires rocks with suitable injectivity, capacity and sealing properties to ensure secure long-term containment of injected CO2. A regional understanding of the subsurface is essential to determine the potential for GCS of a basin and to select target sites. This is best addressed by integrating the basin’s tectono-stratigraphic evolution, its gross depositional environment, and its hydrodynamic, thermal and stress regimes. A basin-scale GCS assessment for the Barrow-Dampier sub-basins was conducted by Geoscience Australia and SLB. The objective of the study is to high-grade geological intervals and sites for potential GCS and to understand potential storage capacity and key risk factors. Stratigraphic and structural mapping of key storage intervals was performed using the reprocessed seismic volume and well database associated with the project. Analysis of critically stressed faults was used to estimate the likelihood of reactivation based on the far-field regional stress field and fault mechanical properties. Pressure, temperature, porosity, permeability, and water geochemistry data have been screened for &gt;500 wells for assessing the storage unit intervals and predicting the hydrodynamic regime. Calibrated 2D basin models provide information on the regional pressure-temperature regime, porosity/permeability distribution, and sealing effectiveness. Potentiometric surface maps for the aquifer systems inform the distribution of potential CO2 plume migration. Results of this integrated regional basin study are used to quantify the risk of identified storage containers and to map the chance of success for GCS at a regional scale. The project results are publicly available via NOPIMS.

Structural framework of the Caswell Sub-basin, North West Shelf, Australia

The Caswell Sub-basin, situated within the Browse Basin in the North West Shelf constitutes one of Australia’s primary hydrocarbon producing regions, with notable gas-condensate producing fields including Ichthys and Prelude. Jurassic syn-rift sandstones are extensively distributed across the basin and serve as one of the major reservoirs. However, reservoir sequences are typically intensely faulted and exhibit heterogeneity in thickness and lithofacies, with some areas experiencing localised erosion on uplifted fault blocks (e.g. Northern Caswell Sub-basin). Hence, understanding the nature of the 3D fault patterns and their growth history is crucial for evaluating the reservoir characteristics for field development and additional exploration activities. This study, therefore, aims to evaluate the structural framework and the tectonic evolution of the Caswell Sub-basin. Detailed structural interpretation of Paleozoic and younger sequences was conducted using multiple 3D seismic datasets extending over Ichthys, Prelude, Lasseter, and Crown fields. Our study focuses mainly on Mesozoic faulting patterns and kinematics evaluated from interpreted structural maps, thickness changes of each stratigraphic interval and fault throw profiles of major bounding faults. The extensional phase during the Early–Middle Jurassic triggered the development of NE–SW trending faults and the deepening of the Brewster Graben. While, from the Late Jurassic to the Early Cretaceous, the development of E–W trending faults in the north of the Crown and Lasseter fields indicate a shift in the regional stress regime. We highlight the importance of evaluating the structural linkage from basement to cover sequences to achieve a comprehensive understanding of reservoirs and associated petroleum systems.

Mapping the Intersubunit Interdomain FMN-Heme Interactions in Neuronal Nitric Oxide Synthase by Targeted Quantitative Cross-Linking Mass Spectrometry.

Nitric oxide synthase (NOS) in mammals is a family of multidomain proteins in which interdomain electron transfer (IET) is controlled by domain-domain interactions. Calmodulin (CaM) binds to the canonical CaM-binding site in the linker region between the FMN and heme domains of NOS and allows tethered FMN domain motions, enabling an intersubunit FMN-heme IET in the output state for NO production. Our previous cross-linking mass spectrometric (XL MS) results demonstrated site-specific protein dynamics in the CaM-responsive regions of rat neuronal NOS (nNOS) reductase construct, a monomeric protein [Jiang et al., Biochemistry, 2023, 62, 2232-2237]. In this work, we have extended our combined approach of XL MS structural mapping and AlphaFold structural prediction to examine the homodimeric nNOS oxygenase/FMN (oxyFMN) construct, an established model of the NOS output state. We employed parallel reaction monitoring (PRM) based quantitative XL MS (qXL MS) to assess the CaM-induced changes in interdomain dynamics and interactions. Intersubunit cross-links were identified by mapping the cross-links onto top AlphaFold structural models, which was complemented by comparing their relative abundances in the cross-linked dimeric and monomeric bands. Furthermore, contrasting the CaM-free and CaM-bound nNOS samples shows that CaM enables the formation of the intersubunit FMN-heme docking complex and that CaM binding induces extensive, allosteric conformational changes across the NOS regions. Moreover, the observed cross-links sites specifically respond to changes in ionic strength. This indicates that interdomain salt bridges are responsible for stabilizing and orienting the output state for efficient FMN-heme IET. Taken together, our targeted qXL MS results have revealed that CaM and ionic strength modulate specific dynamic changes in the CaM/FMN/heme complexes, particularly in the context of intersubunit interdomain FMN-heme interactions.

Sustainable hospitality and tourism in the Anthropocene era: the need for a more radical shift of the current circular economy models

Purpose This paper aims to critically analyse the circular economy (CE) models adopted in hospitality and tourism to tackle societal challenges in the current Anthropocene era, exploring the driving values and sustainability approaches. Design/methodology/approach A systematic literature review was carried out with an increasing level of analysis to delve more in-depth into the ability of the CE models to respond to current societal challenges. The review involved a stepwise analysis, starting with a thematic analysis of 151 papers to create a conceptual structure map of circular hospitality and tourism literature. Based on originality and representativeness, 22 papers were selected and analysed according to Hoffman and Jennings’ (2018; 2021) institutional approach to sustainability, which entails specific archetypes to address the Anthropocene society: market rules, technology fix and cultural re-enlightening. Findings The hospitality and tourism industry has made progress towards implementing CE models. However, CE models in market role and technology fix archetypes may fail to address the current challenges of the Anthropocene era. New culture-led approaches within the cultural re-enlightening archetype, such as the regenerative land practices, a-growth and place-making, and circular society, can foster a more radical shift towards strong sustainability. Research limitations/implications The paper highlights the urgent need for a cultural shift towards radical and strong sustainability, identifying future research directions. Policymakers have a crucial role in shaping sustainability practices consistent with an ecological culture centred on acknowledging planetary boundaries. Originality/value Despite the increasing interest in CE models, it is still debated how the hospitality and tourism industry can continue to thrive while avoiding harmful impacts on the environment and local communities. The study critically reflects on the current contribution of CE models towards strong sustainability in hospitality and tourism.

Structural basis for double-stranded RNA recognition by SID1.

The nucleic acid transport properties of the systemic RNAi-defective (SID) 1 family make them attractive targets for developing RNA-based therapeutics and drugs. However, the molecular basis for double-stranded (ds) RNA recognition by SID1 family remains elusive. Here, we report the cryo-EM structures of Caenorhabditis elegans (c) SID1 alone and in complex with dsRNA, both at a resolution of 2.2 Å. The dimeric cSID1 interacts with two dsRNA molecules simultaneously. The dsRNA is located at the interface between β-strand rich domain (BRD)1 and BRD2 and nearly parallel to the membrane plane. In addition to extensive ionic interactions between basic residues and phosphate backbone, several hydrogen bonds are formed between 2'-hydroxyl group of dsRNA and the contact residues. Additionally, the electrostatic potential surface shows three basic regions are fitted perfectly into three major grooves of dsRNA. These structural characteristics enable cSID1 to bind dsRNA in a sequence-independent manner and to distinguish between DNA and RNA. The cSID1 exhibits no conformational changes upon binding dsRNA, with the exception of a few binding surfaces. Structural mapping of dozens of loss-of-function mutations allows potential interpretation of their diverse functional mechanisms. Our study marks an important step toward mechanistic understanding of the SID1 family-mediated dsRNA uptake.

Multi-exposure image fusion using structural weights and visual saliency map

Multi-exposure image fusion using structural weights and visual saliency map

Possibility and quality assessment in seafloor modeling relative to the sea surface using hybrid data

Possibility and quality assessment in seafloor modeling relative to the sea surface using hybrid data

A low-light image enhancement model based on anisotropic weighted exponential local derivatives

Low-light images incur several complicated degradations such as low brightness, poor contrast, and higher noise. Retinex theory, which decomposes a low-light image into illumination and reflection components based on local image derivatives, is widely used in the field of shimmering image enhancement. In this paper, we propose a new low-light image enhancement model based on the Retinex theory to reduce the above distortions. To be more specific, we first introduce a new structural texture extractor (NSTE) based on the local image derivatives properties to generate the texture and structure maps of the observed images. Compared to existing structural texture extractors, NSTE has two key designs: anisotropic weighting and adaptive exponential term. The aim is to generate structural maps with clear edge and texture maps with salient details. Subsequently, these two images are used to regularize the illumination and reflection components of the variational decomposition model, respectively. Finally, we developed a luminance correction function and a detail enhancement function to enhance the illumination and reflectance, respectively. This aims to improve the viewing experience, mitigate over-enhancement, and minimize detail distortion. We choose the alternating direction method of multipliers (ADMM) to solve the optimization model. Experimental results on several low-light datasets demonstrate that our proposed method can achieve better quantitative and qualitative performance than state-of-the-art methods.