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Keywords = central-marginal hypothesis

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28 pages, 8750 KiB  
Article
A Water Shortage Risk Assessment Model Based on Kernel Density Estimation and Copulas
by Tanghui Qian, Zhengtao Shi, Shixiang Gu, Wenfei Xi, Jing Chen, Jinming Chen, Shihan Bai and Lei Wu
Water 2024, 16(11), 1465; https://doi.org/10.3390/w16111465 - 21 May 2024
Cited by 7 | Viewed by 1866
Abstract
Accurate assessment and prediction of water shortage risk are essential prerequisites for the rational allocation and risk management of water resources. However, previous water shortage risk assessment models based on copulas have strict requirements for data distribution, making them unsuitable for extreme conditions [...] Read more.
Accurate assessment and prediction of water shortage risk are essential prerequisites for the rational allocation and risk management of water resources. However, previous water shortage risk assessment models based on copulas have strict requirements for data distribution, making them unsuitable for extreme conditions such as insufficient data volume and indeterminate distribution shapes. These limitations restrict the applicability of the models and result in lower evaluation accuracy. To address these issues, this paper proposes a water shortage risk assessment model based on kernel density estimation (KDE) and copula functions. This approach not only enhances the robustness and stability of the model but also improves its prediction accuracy. The methodology involves initially utilizing kernel density estimation to quantify the random uncertainties in water supply and demand based on historical statistical data, thereby calculating their respective marginal probability distributions. Subsequently, copula functions are employed to quantify the coupled interdependence between water supply and demand based on these marginal probability distributions, thereby computing the joint probability distribution. Ultimately, the water shortage risk is evaluated based on potential loss rates and occurrence probabilities. This proposed model is applied to assess the water shortage risk of the Yuxi water receiving area in the Central Yunnan Water Diversion Project, and compared with existing models through experimental contrasts. The experimental results demonstrate that the model exhibits evident advantages in terms of robustness, stability, and evaluation accuracy, with a rejection rate of 0 for the null hypothesis of edge probability fitting and a smaller deviation in joint probability fitting compared to the most outstanding model in the field. These findings indicate that the model presented in this paper is capable of adapting to non-ideal scenarios and extreme climatic conditions for water shortage risk assessment, providing reliable prediction outcomes even under extreme circumstances. Therefore, it can serve as a valuable reference and source of inspiration for related engineering applications and technical research. Full article
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32 pages, 6360 KiB  
Article
Is There a Digital Rebound in the Process of Urban Green Development? New Empirical Evidence Using Ensemble Learning Methods
by Ying Ping and Zhuolin Li
Sustainability 2024, 16(10), 4281; https://doi.org/10.3390/su16104281 - 19 May 2024
Cited by 2 | Viewed by 1594
Abstract
The convergence of digitization and greening is an unavoidable path of modern economic progress. Nonetheless, the digital economy does not consistently align with the principles of green development, potentially leading to a rebound effect in urban digitalization initiatives. To investigate the correlation between [...] Read more.
The convergence of digitization and greening is an unavoidable path of modern economic progress. Nonetheless, the digital economy does not consistently align with the principles of green development, potentially leading to a rebound effect in urban digitalization initiatives. To investigate the correlation between the digital rebound effect and urban green development, this study utilizes panel data from Chinese prefecture-level cities spanning from 2011 to 2019. By examining the dual impact of the digital economy on green development, the paper posits a theoretical hypothesis regarding the nonlinear marginal effect of the digital economy. This research demonstrates an inverted U-shaped correlation between the digital economy and urban green development via empirical analyses employing the random forest algorithm and partial dependency plots. It supports the existence of a moderate digital resiliency effect, which eventually reaches a state of stability rather than greatly diminishing the degree of green development in urban areas. In addition, the heterogeneity analysis reveals that the positive effects of the digital economy are more popular in cities located in the eastern and central regions, as well as in the National Comprehensive Pilot Zone for Big Data. However, these effects do not vary significantly among different ranks of cities. The mechanism test found that the information effect and the capital allocation effect are the mechanisms by which the digital economy affects green development, and there is a “U-shaped” relationship between the digital economy and information asymmetry and capital mismatch. According to the study’s results, improving the digital economy’s governance structure continues to make more sense than merely increasing the number of digital inputs. Full article
(This article belongs to the Section Economic and Business Aspects of Sustainability)
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18 pages, 27945 KiB  
Article
Understanding the Deep Structure of the Essaouira Basin Using Gravity Data: Hydrogeological Inferences for a Semiarid Region in Central-Western Morocco
by Abdellah Khouz, Mohammed Jaffal, Jorge Trindade, Blaid Bougadir, Fatima El Bchari, Azzouz Kchikach, Mustapha El Ghorfi, Hassan Ibouh, Mourad Jadoud, Omar Kadiri and Ahmed Manar
Geosciences 2023, 13(11), 345; https://doi.org/10.3390/geosciences13110345 - 10 Nov 2023
Cited by 2 | Viewed by 3773
Abstract
The Essaouira Basin, located in central western Morocco, faces a significant threat of water shortage due to both the substantially reduced rainfall caused by climate change and the continuously increasing demand for this essential resource. Groundwater resources are being increasingly exploited to meet [...] Read more.
The Essaouira Basin, located in central western Morocco, faces a significant threat of water shortage due to both the substantially reduced rainfall caused by climate change and the continuously increasing demand for this essential resource. Groundwater resources are being increasingly exploited to meet the needs of the population, whether for agricultural or domestic purposes. Therefore, it has become necessary to intensify investigations across the entire basin, particularly through indirect methods such as geophysical techniques, to accurately delineate the productive zones. In this context, the present study was undertaken to investigate the deep structure of this basin with the aim of comprehending the functioning of its aquifer system. This study is based on the interpretation of gravity data covering the Essaouira Basin. In addition to their qualitative analysis, these data underwent a methodological approach involving transformations to extract meaningful insights. The observed anomalies were interpreted in terms of (i) thickness variations within the slightly folded sedimentary series of the basin; (ii) Paleozoic basement topography; and (iii) the presence of salt deposits. In fact, among the negative anomalies, some coincide with evaporitic deposits that are known either from the geological outcrops or the seismic surveys carried out in the Essaouira Basin within the framework of petroleum exploration programs, while others coincide with areas of increased thickness of sedimentary sequences. The latter include synclines and basement depressions, where the accumulation of groundwater tends to occur; as a result, they constitute suitable zones for the drilling of water extraction wells. Groundwater flows observed in some existing wells are consistent with this hypothesis. The results of the contact analysis approach implemented within the framework of the study reveals the Essaouira Basin is affected by a fault network whose main direction is parallel to the Atlantic margin (i.e., NNE–SSW). This implies that the extensional tectonic phase responsible for initiating the rifting of the Central Atlantic in the Triassic era has primarily impacted the structural configuration of this basin. This study demonstrates the strong potential of the gravity method as a tool to delineate the deep structure of sedimentary basins and to identify potentially productive groundwater zones. The final results will provide important support to decision makers in sustainable groundwater management, especially in vulnerable areas. Full article
(This article belongs to the Section Hydrogeology)
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39 pages, 3071 KiB  
Article
Food Security beyond Cereals: A Cross-Geographical Comparative Study on Acorn Bread Heritage in the Mediterranean and the Middle East
by Dauro Mattia Zocchi, Camilla Bondioli, Seyed Hamzeh Hosseini, Mohamed Djamel Miara, Carmelo Maria Musarella, Datis Mohammadi, Ajmal Khan Manduzai, Kovan Dilawer Issa, Naji Sulaiman, Chadi Khatib, Hiwa M. Ahmed, Tola Abdulsattar Faraj, Hawraz Ibrahim M. Amin, Faiq H. S. Hussain, Abdullah Faiz, Antonella Pasqualone, Frits Heinrich, Michele Filippo Fontefrancesco and Andrea Pieroni
Foods 2022, 11(23), 3898; https://doi.org/10.3390/foods11233898 - 2 Dec 2022
Cited by 21 | Viewed by 5834
Abstract
This article aims to contribute to the limited literature on traditional gastronomic knowledge concerning acorn-based bread by ethnographically documenting the ingredients, preparation techniques and consumption practices of baked goods made from acorn seeds and flour that are still used today or at least [...] Read more.
This article aims to contribute to the limited literature on traditional gastronomic knowledge concerning acorn-based bread by ethnographically documenting the ingredients, preparation techniques and consumption practices of baked goods made from acorn seeds and flour that are still used today or at least still present in living memory. A qualitative comparative case method was adopted, and ethnographic data were gathered from 67 people in six selected Mediterranean, Central Asian and Middle Eastern countries. The analysis highlighted distinct trajectories in the development of acorn-based bread, showing some differences in terms of ingredients, preparation techniques and baking methods in the two cultural and geographical macro-regions. By exploring the evolution of the alimentary role of acorn bread in the past century, our findings also support the hypothesis that the product, at least during the last two centuries, has mostly been used as a famine food. By acknowledging the cultural importance of acorn fruits and acorn-based products, this study suggests that the rediscovery of acorn-based products and associated traditional knowledge may foster the sustainable development of rural and marginal regions in the Mediterranean, Middle East and Central Asia. This could help to reinforce the resilience of local communities and thus increase food security. Furthermore, reassessing acorns as a foodstuff may aid in developing innovative products in line with emerging trends in the food sector, which is looking for new non-cereal-based bakery products and other novel culinary applications. Full article
(This article belongs to the Section Food Security and Sustainability)
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25 pages, 3806 KiB  
Article
SORAG: Synthetic Data Over-Sampling Strategy on Multi-Label Graphs
by Yijun Duan, Xin Liu, Adam Jatowt, Hai-tao Yu, Steven Lynden, Kyoung-Sook Kim and Akiyoshi Matono
Remote Sens. 2022, 14(18), 4479; https://doi.org/10.3390/rs14184479 - 8 Sep 2022
Cited by 6 | Viewed by 2676
Abstract
In many real-world networks of interest in the field of remote sensing (e.g., public transport networks), nodes are associated with multiple labels, and node classes are imbalanced; that is, some classes have significantly fewer samples than others. However, the research problem of imbalanced [...] Read more.
In many real-world networks of interest in the field of remote sensing (e.g., public transport networks), nodes are associated with multiple labels, and node classes are imbalanced; that is, some classes have significantly fewer samples than others. However, the research problem of imbalanced multi-label graph node classification remains unexplored. This non-trivial task challenges the existing graph neural networks (GNNs) because the majority class can dominate the loss functions of GNNs and result in the overfitting of the majority class features and label correlations. On non-graph data, minority over-sampling methods (such as the synthetic minority over-sampling technique and its variants) have been demonstrated to be effective for the imbalanced data classification problem. This study proposes and validates a new hypothesis with unlabeled data over-sampling, which is meaningless for imbalanced non-graph data; however, feature propagation and topological interplay mechanisms between graph nodes can facilitate the representation learning of imbalanced graphs. Furthermore, we determine empirically that ensemble data synthesis through the creation of virtual minority samples in the central region of a minority and generation of virtual unlabeled samples in the boundary region between a minority and majority is the best practice for the imbalanced multi-label graph node classification task. Our proposed novel data over-sampling framework is evaluated using multiple real-world network datasets, and it outperforms diverse, strong benchmark models by a large margin. Full article
(This article belongs to the Special Issue Artificial Intelligence-Based Learning Approaches for Remote Sensing)
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14 pages, 312 KiB  
Article
Environmental Impact of Urbanization, Bank Credits, and Energy Use in the UAE—A Tourism-Induced EKC Model
by Sudipa Majumdar and Cody Morris Paris
Sustainability 2022, 14(13), 7834; https://doi.org/10.3390/su14137834 - 27 Jun 2022
Cited by 17 | Viewed by 5329
Abstract
The United Arab Emirates (UAE) has developed rapidly into one of the highest per capita income nations globally. The travel and tourism sector is a central contributor to the Gross Domestic Product (GDP), employment, foreign exchange earnings, and the country’s economic diversification strategy. [...] Read more.
The United Arab Emirates (UAE) has developed rapidly into one of the highest per capita income nations globally. The travel and tourism sector is a central contributor to the Gross Domestic Product (GDP), employment, foreign exchange earnings, and the country’s economic diversification strategy. However, the rapid growth of the sector and increase in international tourist arrivals are also major contributors to carbon emissions and long-term environmental challenges. In this context, we employed a tourism-induced Environmental Kuznets Curve (EKC) model for the UAE from 1984 to 2019. The study applied an Autoregressive Distributed Lag (ARDL) model to determine the marginal impact of tourist arrivals and related variables, namely, bank credits to the private sector, urbanization, and energy use, on CO2 emissions. The Pesaran bounds test indicated redundancy of short run estimates. The long-run coefficients confirmed the EKC hypothesis of inverted U-shape for carbon emissions and per capita income, along with environmental degradation due to tourist arrivals and financial development. Notably, urbanization and energy use highlighted the positive steps taken by the government. Granger causality tests indicated a unidirectional association from GDP, bank credits, and energy consumption to carbon emissions. Importantly, tourist arrivals and urbanization had bidirectional causality with carbon dioxide levels. This study is the first to apply the tourism-induced EKC model to the UAE, and the findings have important implications for policymakers and practitioners. The causality results highlight the need to balance tourism targets and sustainable economic growth through the adoption of ‘green’ standards. The results also indicate the potential importance of financial sector efforts to boost green investments and implement clean energy-related technologies. Full article
21 pages, 3053 KiB  
Review
From Bench to Bedside in Precision Medicine: Diabetes Mellitus and Peri-Implantitis Clinical Indices with a Short-Term Follow-Up: A Systematic Review and Meta-Analysis
by Mario Dioguardi, Stefania Cantore, Salvatore Scacco, Cristian Quarta, Diego Sovereto, Francesca Spirito, Mario Alovisi, Giuseppe Troiano, Riccardo Aiuto, Daniele Garcovich, Vito Crincoli, Luigi Laino, Michele Covelli, Annarita Malcangi, Lorenzo Lo Muzio, Andrea Ballini and Michele Di Cosola
J. Pers. Med. 2022, 12(2), 235; https://doi.org/10.3390/jpm12020235 - 8 Feb 2022
Cited by 20 | Viewed by 3631
Abstract
Background and objective: Diabetes mellitus (DM) refers to a group of metabolic disorders characterized by hyperglycemia resulting from impaired secretion or action of insulin. The high levels of glucose in the blood can negatively affect the healing processes through alterations in vascularization, [...] Read more.
Background and objective: Diabetes mellitus (DM) refers to a group of metabolic disorders characterized by hyperglycemia resulting from impaired secretion or action of insulin. The high levels of glucose in the blood can negatively affect the healing processes through alterations in vascularization, bone remodeling, and with increased susceptibility to infections. Diabetes mellitus is therefore a risk factor not only for many systemic diseases, but also for localized problems such as peri-implantitis. The objective of this systematic review was to identify a clear relationship between peri-implant inflammation indices and glycemic levels, through the investigation of prospective studies that report data on a short-term follow-up period. Our hypothesis was that peri-implant inflammatory indices may already present themselves in a statistically significant way as altered in patients with DM compared to patients without DM. Materials and methods: This review was reported according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA). Results: More than 992 records were identified in the PubMed, Scopus, and Cochrane Central Register of Controlled Trial electronic databases and only seven studies were included in the meta-analysis. The results of the meta-analysis report worse outcomes in patients with DM, even in the short period of six months, for peri-implatitis inflammation indices, such as Marginal bone loss (standardized (Std). mean difference (MD) 12\6 months 0.81 [0.45, 1.17]\1.82 [0.53, 3.10]), Bleeding on probing (Std. MD 12\6 months 2.84 [1.34, 4.34]\3.44 [1.41, 5.50]), Probing depth (Std. MD 12\6 months 1.14 [0.60, 1.68]\2.24 [0.66, 3.83]), and the plaque index (Std. MD 12 months 2.83 [0.09, 5.57]). Conclusion: The literature linking glycaemic control to peri-implant disease is highly heterogeneous due to lack of consistency of the definition of peri-implantitis and its clinical indicators among studies. Therefore, interpretation of finding and relevance to clinical practice should be considered on individual bases. In the era of personalized medicine, the clinician should utilize individualized information from translational researches and analyze all risk factors to provide the patient with evidence-based treatment options. Full article
(This article belongs to the Special Issue New Trends in Precision Medicine)
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24 pages, 26133 KiB  
Article
Genetic Distinctiveness but Low Diversity Characterizes Rear-Edge Thuja standishii (Gordon) Carr. (Cupressaceae) Populations in Southwest Japan
by James R. P. Worth, Ichiro Tamaki, Ikutaro Tsuyama, Peter A. Harrison, Kyoko Sugai, Hitoshi Sakio, Mineaki Aizawa and Satoshi Kikuchi
Diversity 2021, 13(5), 185; https://doi.org/10.3390/d13050185 - 28 Apr 2021
Cited by 6 | Viewed by 3449
Abstract
Rear-edge populations are of significant scientific interest because they can contain allelic variation not found in core-range populations. However, such populations can differ in their level of genetic diversity and divergence reflecting variation in life-history traits, demographic histories and human impacts. Using 13 [...] Read more.
Rear-edge populations are of significant scientific interest because they can contain allelic variation not found in core-range populations. However, such populations can differ in their level of genetic diversity and divergence reflecting variation in life-history traits, demographic histories and human impacts. Using 13 EST-microsatellites, we investigated the genetic diversity and differentiation of rear-edge populations of the Japanese endemic conifer Thuja standishii (Gordon) Carr. in southwest Japan from the core-range in northeast Japan. Range-wide genetic differentiation was moderate (Fst = 0.087), with northeast populations weakly differentiated (Fst = 0.047), but harboring high genetic diversity (average population-level Ar = 4.76 and Ho = 0.59). In contrast, rear-edge populations were genetically diverged (Fst = 0.168), but contained few unique alleles with lower genetic diversity (Ar = 3.73, Ho = 0.49). The divergence between rear-edge populations exceeding levels observed in the core-range and results from ABC analysis and species distribution modelling suggest that these populations are most likely relicts of the Last Glacial Maximum. However, despite long term persistence, low effective population size, low migration between populations and genetic drift have worked to promote the genetic differentiation of southwest Japan populations of T. standishii without the accumulation of unique alleles. Full article
(This article belongs to the Special Issue Evolutionary Ecology and Conservation of Native Plants)
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16 pages, 6260 KiB  
Article
Resistance, Recovery and Resilience of Two Co-Occurring Palaeotropical Pinus Species Differing in the Sizes of Their Distribution Areas
by Le T. Ho, Jana Hoppe and Frank M. Thomas
Forests 2021, 12(4), 511; https://doi.org/10.3390/f12040511 - 20 Apr 2021
Cited by 3 | Viewed by 3526
Abstract
Using a dendrochronological approach, we determined the resistance, recovery and resilience of the radial stem increment towards episodes of growth decline, and the accompanying variation of 13C discrimination against atmospheric CO213C) in tree rings of two palaeotropical pine [...] Read more.
Using a dendrochronological approach, we determined the resistance, recovery and resilience of the radial stem increment towards episodes of growth decline, and the accompanying variation of 13C discrimination against atmospheric CO213C) in tree rings of two palaeotropical pine species. These species co-occur in the mountain ranges of south–central Vietnam (1500–1600 m a.s.l.), but differ largely in their areas of distribution (Pinus kesiya from northeast India to the Philippines; P. dalatensis only in south and central Vietnam and in some isolated populations in Laos). For P. dalatensis, a robust growth chronology covering the past 290 years could be set up for the first time in the study region. For P. kesiya, the 140-year chronology constructed was the longest that could be established to date in that region for this species. In the first 40 years of the trees’ lives, the stem diameter increment was significantly larger in P. kesiya, but levelled off and even decreased after 100 years, whereas P. dalatensis exhibited a continuous growth up to an age of almost 300 years. Tree-ring growth of P. kesiya was negatively related to temperature in the wet months and season of the current year and in October (humid transition period) of the preceding year and to precipitation in August (monsoon season), but positively to precipitation in December (dry season) of the current year. The P. dalatensis chronologies exhibited no significant correlation with temperature or precipitation. Negative correlations between BAI and Δ13C indicate a lack of growth impairment by drought in both species. Regression analyses revealed a lower resilience of P. dalatensis upon episodes of growth decline compared to P. kesiya, but, contrary to our hypothesis, mean values of the three sensitivity parameters did not differ significantly between these species. Nevertheless, the vigorous growth of P. kesiya, which does not fall behind that of P. dalatensis even at the margin of its distribution area under below-optimum edaphic conditions, is indicative of a relatively high plasticity of this species towards environmental factors compared to P. dalatensis, which, in tendency, is less resilient upon environmental stress even in the “core” region of its occurrence. Full article
(This article belongs to the Special Issue Modelling and Managing the Dynamics of Pine Forests)
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13 pages, 2623 KiB  
Article
Tectonic Setting of the Eastern Margin of the Sino-Korean Block in the Pennsylvanian: Constraints from Detrital Zircon Ages
by Mun Gi Kim, Yong Il Lee and Taejin Choi
Minerals 2020, 10(6), 527; https://doi.org/10.3390/min10060527 - 9 Jun 2020
Cited by 6 | Viewed by 3031
Abstract
To test the previous hypothesis that upper Paleozoic sediments in the eastern Sino-Korean Block were mostly derived from the paleo-orogen located to the east, we compared published and new U–Pb age data of detrital zircons from Pennsylvanian strata distributed in the Sino-Korean Block [...] Read more.
To test the previous hypothesis that upper Paleozoic sediments in the eastern Sino-Korean Block were mostly derived from the paleo-orogen located to the east, we compared published and new U–Pb age data of detrital zircons from Pennsylvanian strata distributed in the Sino-Korean Block (SKB). The age distributions of detrital zircons from different localities of Pennsylvanian strata in North China reflect varying contributions from the Inner Mongolia Paleo-uplift in the north and the Central China Orogenic Belt in the south. The supply of detritus from the northern source to distant areas, however, appears to have been limited during the Pennsylvanian times. The age distributions of detrital zircons from Korean Pennsylvanian strata located in the east of the SKB are characterized by a dense cluster of 1.84–1.90 Ga and differ from those of North China. The Korean age characteristic is best explained by strong influences of the detritus derived from the Paleoproterozoic Yeongnam Massif in southeastern Korea. Along with the significant number of zircons that record syn- to near-depositional magmatic activities, this observation supports the hypothesis of the existence of an active continental margin setting in the east of the SKB. Full article
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12 pages, 3976 KiB  
Article
Geographical Gradients of Genetic Diversity and Differentiation among the Southernmost Marginal Populations of Abies sachalinensis Revealed by EST-SSR Polymorphism
by Keiko Kitamura, Kentaro Uchiyama, Saneyoshi Ueno, Wataru Ishizuka, Ikutaro Tsuyama and Susumu Goto
Forests 2020, 11(2), 233; https://doi.org/10.3390/f11020233 - 20 Feb 2020
Cited by 27 | Viewed by 4219
Abstract
Research Highlights: We detected the longitudinal gradients of genetic diversity parameters, such as the number of alleles, effective number of alleles, heterozygosity, and inbreeding coefficient, and found that these might be attributable to climatic conditions, such as temperature and snow depth. Background [...] Read more.
Research Highlights: We detected the longitudinal gradients of genetic diversity parameters, such as the number of alleles, effective number of alleles, heterozygosity, and inbreeding coefficient, and found that these might be attributable to climatic conditions, such as temperature and snow depth. Background and Objectives: Genetic diversity among local populations of a plant species at its distributional margin has long been of interest in ecological genetics. Populations at the distribution center grow well in favorable conditions, but those at the range margins are exposed to unfavorable environments, and the environmental conditions at establishment sites might reflect the genetic diversity of local populations. This is known as the central-marginal hypothesis in which marginal populations show lower genetic variation and higher differentiation than in central populations. In addition, genetic variation in a local population is influenced by phylogenetic constraints and the population history of selection under environmental constraints. In this study, we investigated this hypothesis in relation to Abies sachalinensis, a major conifer species in Hokkaido. Materials and Methods: A total of 1189 trees from 25 natural populations were analyzed using 19 EST-SSR loci. Results: The eastern populations, namely, those in the species distribution center, showed greater genetic diversity than did the western peripheral populations. Another important finding is that the southwestern marginal populations were genetically differentiated from the other populations. Conclusions: These differences might be due to genetic drift in the small and isolated populations at the range margin. Therefore, our results indicated that the central-marginal hypothesis held true for the southernmost A. sachalinensis populations in Hokkaido. Full article
(This article belongs to the Special Issue Genetics and Improvement of Forest Trees)
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23 pages, 1902 KiB  
Review
p53 as a Dichotomous Regulator of Liver Disease: The Dose Makes the Medicine
by Jelena Krstic, Markus Galhuber, Tim J. Schulz, Michael Schupp and Andreas Prokesch
Int. J. Mol. Sci. 2018, 19(3), 921; https://doi.org/10.3390/ijms19030921 - 20 Mar 2018
Cited by 51 | Viewed by 8221
Abstract
Lifestyle-related disorders, such as the metabolic syndrome, have become a primary risk factor for the development of liver pathologies that can progress from hepatic steatosis, hepatic insulin resistance, steatohepatitis, fibrosis and cirrhosis, to the most severe condition of hepatocellular carcinoma (HCC). While the [...] Read more.
Lifestyle-related disorders, such as the metabolic syndrome, have become a primary risk factor for the development of liver pathologies that can progress from hepatic steatosis, hepatic insulin resistance, steatohepatitis, fibrosis and cirrhosis, to the most severe condition of hepatocellular carcinoma (HCC). While the prevalence of liver pathologies is steadily increasing in modern societies, there are currently no approved drugs other than chemotherapeutic intervention in late stage HCC. Hence, there is a pressing need to identify and investigate causative molecular pathways that can yield new therapeutic avenues. The transcription factor p53 is well established as a tumor suppressor and has recently been described as a central metabolic player both in physiological and pathological settings. Given that liver is a dynamic tissue with direct exposition to ingested nutrients, hepatic p53, by integrating cellular stress response, metabolism and cell cycle regulation, has emerged as an important regulator of liver homeostasis and dysfunction. The underlying evidence is reviewed herein, with a focus on clinical data and animal studies that highlight a direct influence of p53 activity on different stages of liver diseases. Based on current literature showing that activation of p53 signaling can either attenuate or fuel liver disease, we herein discuss the hypothesis that, while hyper-activation or loss of function can cause disease, moderate induction of hepatic p53 within physiological margins could be beneficial in the prevention and treatment of liver pathologies. Hence, stimuli that lead to a moderate and temporary p53 activation could present new therapeutic approaches through several entry points in the cascade from hepatic steatosis to HCC. Full article
(This article belongs to the Special Issue Molecular Mechanisms of Human Liver Diseases)
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23 pages, 10570 KiB  
Article
Unassisted Quantitative Evaluation of Despeckling Filters
by Luis Gomez, Raydonal Ospina and Alejandro C. Frery
Remote Sens. 2017, 9(4), 389; https://doi.org/10.3390/rs9040389 - 20 Apr 2017
Cited by 81 | Viewed by 7864
Abstract
SAR (Synthetic Aperture Radar) imaging plays a central role in Remote Sensing due to, among other important features, its ability to provide high-resolution, day-and-night and almost weather-independent images. SAR images are affected from a granular contamination, speckle, that can be described by a [...] Read more.
SAR (Synthetic Aperture Radar) imaging plays a central role in Remote Sensing due to, among other important features, its ability to provide high-resolution, day-and-night and almost weather-independent images. SAR images are affected from a granular contamination, speckle, that can be described by a multiplicative model. Many despeckling techniques have been proposed in the literature, as well as measures of the quality of the results they provide. Assuming the multiplicative model, the observed image Z is the product of two independent fields: the backscatter X and the speckle Y. The result of any speckle filter is X ^ , an estimator of the backscatter X, based solely on the observed data Z. An ideal estimator would be the one for which the ratio of the observed image to the filtered one I = Z / X ^ is only speckle: a collection of independent identically distributed samples from Gamma variates. We, then, assess the quality of a filter by the closeness of I to the hypothesis that it is adherent to the statistical properties of pure speckle. We analyze filters through the ratio image they produce with regards to first- and second-order statistics: the former check marginal properties, while the latter verifies lack of structure. A new quantitative image-quality index is then defined, and applied to state-of-the-art despeckling filters. This new measure provides consistent results with commonly used quality measures (equivalent number of looks, PSNR, MSSIM, β edge correlation, and preservation of the mean), and ranks the filters results also in agreement with their visual analysis. We conclude our study showing that the proposed measure can be successfully used to optimize the (often many) parameters that define a speckle filter. Full article
(This article belongs to the Special Issue Learning to Understand Remote Sensing Images)
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