Big Patches Research Articles

A LLM-Based Hybrid-Transformer Diagnosis System in Healthcare.

The application of computer vision-powered large language models (LLMs) for medical image diagnosis has significantly advanced healthcare systems. Recent progress in developing symmetrical architectures has greatly impacted various medical imaging tasks. While CNNs or RNNs have demonstrated excellent performance, these architectures often face notable limitations of substantial losses in detailed information, such as requiring to capture global semantic information effectively and relying heavily on deep encoders and aggressive downsampling. This paper introduces a novel LLM-based Hybrid-Transformer Network (HybridTransNet) designed to encode tokenized Big Data patches with the transformer mechanism, which elegantly embeds multimodal data of varying sizes as token sequence inputs of LLMS. Subsequently, the network performs both inter-scale and intra-scale self-attention, processing data features through a transformer-based symmetric architecture with a refining module, which facilitates accurately recovering both local and global context information. Additionally, the output is refined using a novel fuzzy selector. Compared to other existing methods on two distinct datasets, the experimental findings and formal assessment demonstrate that our LLM-based HybridTransNet provides superior performance for brain tumor diagnosis in healthcare informatics.

Effects of multi-scale structure of blue-green space on urban forest carbon density: Beijing, China case study

Landscape structure influences the amount of carbon that can be stored in an ecosystem. Currently, majority of research have been focused on the responses of landscape structure and functional relationships to urbanization, and few have specifically focused on blue-green space. In this study, Beijing was used as a case study to explore the relationship among the blue-green spatial planning structure of green belts, green wedges and green ways, the landscape configuration of blue-green element and carbon storage of urban forest. The blue-green elements were classified using high-resolution remote sensing images (0.8 m) and the above-ground carbon storage estimations of urban forest based on 1307 field survey samples. The results show that green belts and green wedges have a higher coverage percentage of blue-green space and big blue-green patches than that of built-up areas. However, they have lower carbon density in urban forests. The shannon's diversity index of blue-green space was found to have a binary relationship with carbon density, in which, urban forests and water bodies were the key combination in increasing carbon density. The presence of water bodies in urban forests increases the carbon density to up to 1000 m. The effect of farmland and grassland on carbon density was found to be uncertain. With this, this study provides basis for sustainable planning and management of blue-green spaces.

Soil properties and plant species can predict population size and potential introduction sites of the endangered orchid Cypripedium calceolus

Background and AimsTo counteract the ongoing worldwide biodiversity loss, conservation actions are required to re-establish populations of threatened species. Two key factors predominantly involved in finding the most suitable habitats for endangered plant species are the surrounding plant community composition and the physicochemical parameters of the soil rooting zone. However, such factors are likely to be context- and species-dependent, so it remains unclear to what extent they influence the performance of target species.MethodsWe studied large and small Swiss populations of the endangered orchid Cypripedium calceolus. We measured functional traits related to C. calceolus plant and population performance (clonal patch area, plant height, number, of leaf, stems, flowers and fruits), realized vegetation surveys, soil profile analyses, and tested for relationships between plant traits and the surrounding vegetation structure or soil physicochemical parameters.ResultsLarge populations contained bigger patches with more stems and leaves, and produced more flower per individual than small populations. Neither vegetation alliances nor soil classes per se could predict C. calceolus functional traits and population size. However, functional traits explaining population performance and size were related to specific soil parameters (soil organic matter content, pH and phosphorus), in addition to a combination of presence-absence of plant indicator species, relating to ecotones between forests and clearings.ConclusionWe show that even for species that can grow across a wide range of vegetation groups both indicator species and specific soil parameters can be used to assess the most favourable sites to implement (re)-introduction actions.

Identification of rose black spot pathogen in Sa Đéc city, Đồng Tháp province of Vietnam

Black spot is one of the most destructive diseases of roses, causing premature defoliation, thus progressively weakening the plant and even leading to death. This study aimed at identifying the pathogen causing black spot on Rosa chinensis Jacq. cv. nhung (Hồng Nhung) and R. chinensis Jacq. var. minima (Hồng Tỉ Muội) in Sa Đéc city, Đồng Tháp province, Vietnam, using a combination of conidia morphology and pathogenicity tests including detached leaf and intact plant techniques. A total of 32 infected leaf samples with the black spot typical symptoms were collected from six rose cultivation areas. The morphological characterization of the conidia obtained from these samples was elliptical, hyaline, two-celled and had vacuole-like structures, similar to those produced by Diplocarpon. In pathogenicity test, the symptoms were observed on cv. nhung but not var. minima in the detached leaf technique while symptoms were observed on both cultivars in intact plants technique. These included black spots with perforated edges, aggregating into bigger patches. The infected leaves could yellow and defoliate at 21 days after inoculation. Compared to the previous pathogenic studies and description of diseases on roses, the fungal pathogen was identified as fungus Diplocarpon rosae.

Matrix completion methods for the total electron content video reconstruction

The total electron content (TEC) maps can be used to estimate the signal delay of GPS due to the ionospheric electron content between a receiver and satellite. This delay can result in GPS positioning error. Thus, it is important to monitor the TEC maps. The observed TEC maps have big patches of missingness in the ocean and scattered small areas of missingness on the land. In this paper we propose several extensions of existing matrix completion algorithms to achieve TEC map reconstruction, accounting for spatial smoothness and temporal consistency while preserving important structures of the TEC maps. We call the proposed method video imputation with softImpute, temporal smoothing and auxiliary data (VISTA). Numerical simulations that mimic patterns of real data are given. We show that our proposed method achieves better reconstructed TEC maps, as compared to existing methods in literature. Our proposed computational algorithm is general and can be readily applied for other problems besides TEC map reconstruction.

Evaluation of the safety, tolerability and plasma vitamin D response to long-term use of patented transdermal vitamin D patches in healthy adults: a randomised parallel pilot study

BackgroundVitamin D delivered transdermally may suppress hyperactivity in nociceptor pain receptors and alter pain intensity, offering a useful addition to localised pain management in varying clinical settings. Currently, little is...

A regularization‐based deep unsupervised model for affine multimodal co‐registration

AbstractExtensive network receptive field is key for unsupervised affine registration because instead of deformable registration that takes care of local subtleties, the affine registration is global so that the last layers need to see big patches of the organ‐in‐interest. To extend the network's receptive field, we need to go for deeper networks, which causes producing complex models. On the other hand, affine transformation is restricted by its low degree‐of‐freedom (DoF) where larger models increasingly develop the hazard of overfitting. To worsen the situation, the regularizer module cannot be applied to the affine transformation with such a restricted DoF. In this paper, we propose a differentiable computational layer to convert the affine transformation outputted by the network to its corresponding dense displacement field. Such an affine‐to‐field layer enables us to apply different regularization terms on the outputted transformation in order to avoid the overfitting phenomenon while deepening the network. The proposed approach was evaluated on an annotated hard multimodal dataset containing 1109 pairs of CT/MR images of the brain with different heterogeneity for example, variety in scanners, setups and resolutions. Based on the results, the proposed customized layer is fully successful to handle the overfitting for deeper networks that are able to produce richer transformations than the shallower networks from different evaluation metrics for example, in target registration error the proposed network with seven layers has a 13.3% (or 9.1 mm) improvement in performance. The implementation of the proposed customized affine‐to‐field layer in the Python, Keras package with the Tensorflow backend can be publically accessed via https://github.com/boveiri/Deep-coReg.

Radon descriptor-based machine learning using CT images to predict the fat tissue on left atrium in the heart.

Heart disease has a higher fatality rate than any other disease. Increased Atrial fat on the left atrium has been discovered to cause Atrial Fibrillation (AF) in most patients. AF can put one's life at risk and eventually lead to death. AF might worsen over time; therefore, it is crucial to have an early diagnosis and treatment. To evaluate the left atrium fat tissue pattern using Radon descriptor-based machine learning. This study developed a bridge between the Radon transform framework and machine learning to distinguish two distinct patterns. Motivated by a Radon descriptor-based machine learning approach, the patches of eight patients from CT images of the heart were used and categorized into "epicardial fat tissue" and "nonfat tissue" groups. The 10 feature vectors are extracted from each big patch using Radon descriptors and then fed into a traditional machine learning model. The results show that the proposed methodology discriminates between fat tissues and nonfat tissues clearly. KNN has shown the best performance with 96.77% specificity, 98.28% sensitivity, and 97.50% accuracy. To our knowledge, this study is the first attempt to provide a Radon transform-based machine learning method to distinguish between fat tissue and nonfat tissue on the left atrium. Our proposed research method could be potentially used in advanced interventions.

Multi-Scale Pooling In Deep Neural Networks For Dense Crowd Estimation

State-of-the-art-methods for counting persons in dense crowded places lack in estimating accurate crowd density due to following reasons. They typically apply the same filters over a complete image or over big image patches. Only then the perspective distortion can be compensated by estimating local scale. It is achieved by training an additional classifier with the optimal kernel size chosen from limited choices. These methods are restricted to the context they are applied on because they are not end-to-end trainable; cannot justify quick scale changes because they allocate a single scale to big image patches; and can only utilize a narrow range of receptive fields for the networks to be of a feasible size. In this study, we bring in an end-to-end trainable deep architecture that merges features achieved from multiple kernels of different sizes and learns various essential features such as quick scale changes and to utilize the right context at each image location. This technique flexibly encodes scale of related information to precisely predict crowd density. The training and validation loss of the proposed approach is 5% and 4% lower than the state-of-the-art context aware method, respectively.

TOWARDS DETECTING FLOATING OBJECTS ON A GLOBAL SCALE WITH LEARNED SPATIAL FEATURES USING SENTINEL 2

Abstract. Marine litter is a growing problem that has been attracting attention and raising concerns over the last years. Significant quantities of plastic can be found in the oceans due to the unfiltered discharge of waste into rivers, poor waste management, or lost fishing nets. The floating elements drift on the surface of water bodies and can be aggregated by processes, such as river plumes, windrows, oceanic fronts, or currents. In this paper, we focus on detecting big patches of floating objects that can contain plastic as well as other materials with optical Sentinel 2 data. In contrast to previous work that focuses on pixel-wise spectral responses of some bands, we employ a deep learning predictor that learns the spatial characteristics of floating objects. Along with this work, we provide a hand-labeled Sentinel 2 dataset of floating objects on the sea surface and other water bodies such as lakes together with pre-trained deep learning models. Our experiments demonstrate that harnessing the spatial patterns learned with a CNN is advantageous over pixel-wise classifications that use hand-crafted features. We further provide an analysis of the categories of floating objects that we captured while labeling the dataset and analyze the feature importance for the CNN predictions. Finally, we outline the limitations of trained CNN on several systematic failure cases that we would like to address in future work by increasing the diversity in the dataset and tackling the domain shift between regions and satellite acquisitions. The dataset introduced in this work is the first to provide public large-scale data for floating litter detection and we hope it will give more insights into developing techniques for floating litter detection and classification. Source code and data are available at https://github.com/ESA-PhiLab/floatingobjects.

Multiple Reliable Structured Patches for Object Tracking

It is essential to build the effective appearance model for object tracking in computer vision. Most object trackers can be roughly divided into two categories according to the appearance model: the bounding box model and the patch model. The bounding box model cannot handle shape deformation and occlusion of the non-rigid moving object effectively. The patch model is prone to be disturbed by complex backgrounds. In this paper, we propose a robust multi-structured-patch appearance model to represent the target for object tracking. The proposed appearance model is aimed to exploit and identify reliable patches that can be tracked effectively through the whole tracking process. According to attention mechanism in biological vision system, a coarse-to-fine strategy is usually used to search the target. Therefore, the proposed appearance model is represented by robust patches in different sizes, in which the bigger patches search the rough region of the target and the smaller patches estimate the accurate location. Experimental results on OTB100 dataset show that the proposed method outperforms state-of-the-art trackers.

The Dream of the Royal Road: Psychoanalysis and the Post

The Dream of the Royal Road:Psychoanalysis and the Post Ross Truscott (bio) Dreams are the bearers of repressed wishes—this is the thesis that arrived in 1900 with the publication of Sigmund Freud's Interpreta-tion of Dreams: dreams provide hallucinatory gratification of wishes associated with the first stages of life, which are disguised, under the watch of psychic censorship, through what Freud calls dream-work, primarily through condensation and displacement. There is a widely held assumption that Freud's method for analyzing the distortions of repressed wishes can be applied to any number of textual objects, that one can, as Marjorie Garber puts it, "read culture as if it were structured like a dream" (9). Or, as Claudia Lapping puts it, "symbolic associations between elements in diverse discursive artefacts can be interpreted in a similar way to the patient's associations to the elements of a dream" (43). According to this assumption, to which Freud appears to lend Interpretation, one can use it as a methodological resource to read almost anything. It has been an enabling assumption not least for scholars of postcoloniality, who have read colonial discourse as if it were structured like a dream. For Stuart Hall, for instance, racism, no longer brazen, often highly censored, functions "rather more like Freud's dream-work than like anything else" (15). Or, as Robert Young argues from a different angle, Interpretation offers "a possible way of reading the invisible, the subaltern, those whose forms of public representation distort their fundamental being" (2014, 375). Compelling as these and other postcolonial interventions have been, this kind of application of psychoanalysis no longer seems to me quite that straightforward, and not only on account of the differences [End Page 69] between dreams and others kinds of wish fulfillment to which Freud draws attention. Certainly not when it comes to reading letters psychoanalytically—letters but also, potentially, the colonial archive in general, insofar as it is composed, at least in large part, of documents sent through the post. Freud first outlines his thesis of wish fulfillment through an analysis of one of his own dreams, the specimen dream. He had, he explains, been treating a young woman, Irma—a pseudonym Freud gives her—for hysteria, though the treatment had broken off for the summer vacation. The treatment, Freud notes, had relieved some of her anxiety but had not eradicated her symptoms. A colleague of Freud's and friend of Irma's family, Otto in Freud's account—another pseudonym—had paid him a visit the previous day, and Freud had questioned him about her state. "Better, but not quite well," was Otto's response, in which, Freud states, he "detected a reproof" (1900, 131). Anxious about the failure of the treatment, Freud wrote out Irma's case history, intending to send it to Dr. M., a senior in Freud's medical circle—Josef Breuer—from whom Freud sought justification for his treatment of Irma. After which, still occupied with the case, he fell asleep and dreamed the following: A large hall—numerous guests, whom we were receiving [empfangen].—Among them was Irma. I at once took her on one side, as though to answer her letter [ihren Brief zubeantworten] and to reproach her for not having accepted my "solution [Lösung]" yet. I said to her: "If you still get pains, it's really only your fault." She replied: "If you only knew what pains I've got now in my throat and stomach and abdomen—it's choking me"—I was alarmed and looked at her. She looked pale and puffy. I thought to myself that after all I must be missing some organic trouble. I took her to the window and looked down her throat, and she showed signs of recalcitrance, like women with artificial dentures. I thought to myself that there was really no need for her to do that.—She then opened her mouth properly and on the right I found a big white patch; at another place I saw extensive whitish grey scabs upon some remarkable curly structures which were evidently modelled on the turbinal bones of the nose.—I at once called in Dr M., and...

The Dream of the Royal Road: Psychoanalysis and the Post

The Dream of the Royal Road:Psychoanalysis and the Post Ross Truscott (bio) Dreams are the bearers of repressed wishes—this is the thesis that arrived in 1900 with the publication of Sigmund Freud's Interpreta-tion of Dreams: dreams provide hallucinatory gratification of wishes associated with the first stages of life, which are disguised, under the watch of psychic censorship, through what Freud calls dream-work, primarily through condensation and displacement. There is a widely held assumption that Freud's method for analyzing the distortions of repressed wishes can be applied to any number of textual objects, that one can, as Marjorie Garber puts it, "read culture as if it were structured like a dream" (9). Or, as Claudia Lapping puts it, "symbolic associations between elements in diverse discursive artefacts can be interpreted in a similar way to the patient's associations to the elements of a dream" (43). According to this assumption, to which Freud appears to lend Interpretation, one can use it as a methodological resource to read almost anything. It has been an enabling assumption not least for scholars of postcoloniality, who have read colonial discourse as if it were structured like a dream. For Stuart Hall, for instance, racism, no longer brazen, often highly censored, functions "rather more like Freud's dream-work than like anything else" (15). Or, as Robert Young argues from a different angle, Interpretation offers "a possible way of reading the invisible, the subaltern, those whose forms of public representation distort their fundamental being" (2014, 375). Compelling as these and other postcolonial interventions have been, this kind of application of psychoanalysis no longer seems to me quite that straightforward, and not only on account of the differences [End Page 69] between dreams and others kinds of wish fulfillment to which Freud draws attention. Certainly not when it comes to reading letters psychoanalytically—letters but also, potentially, the colonial archive in general, insofar as it is composed, at least in large part, of documents sent through the post. Freud first outlines his thesis of wish fulfillment through an analysis of one of his own dreams, the specimen dream. He had, he explains, been treating a young woman, Irma—a pseudonym Freud gives her—for hysteria, though the treatment had broken off for the summer vacation. The treatment, Freud notes, had relieved some of her anxiety but had not eradicated her symptoms. A colleague of Freud's and friend of Irma's family, Otto in Freud's account—another pseudonym—had paid him a visit the previous day, and Freud had questioned him about her state. "Better, but not quite well," was Otto's response, in which, Freud states, he "detected a reproof" (1900, 131). Anxious about the failure of the treatment, Freud wrote out Irma's case history, intending to send it to Dr. M., a senior in Freud's medical circle—Josef Breuer—from whom Freud sought justification for his treatment of Irma. After which, still occupied with the case, he fell asleep and dreamed the following: A large hall—numerous guests, whom we were receiving [empfangen].—Among them was Irma. I at once took her on one side, as though to answer her letter [ihren Brief zubeantworten] and to reproach her for not having accepted my "solution [Lösung]" yet. I said to her: "If you still get pains, it's really only your fault." She replied: "If you only knew what pains I've got now in my throat and stomach and abdomen—it's choking me"—I was alarmed and looked at her. She looked pale and puffy. I thought to myself that after all I must be missing some organic trouble. I took her to the window and looked down her throat, and she showed signs of recalcitrance, like women with artificial dentures. I thought to myself that there was really no need for her to do that.—She then opened her mouth properly and on the right I found a big white patch; at another place I saw extensive whitish grey scabs upon some remarkable curly structures which were evidently modelled on the turbinal bones of the nose.—I at once called in Dr M., and...

Cross-Border Comparison of Non-Forest Woody Vegetation in the White Carpathians (Central Europe) Over Last 65 Years

Abstract Landscape structure is determined by human activities and natural processes. Despite both influences are described in many studies, there remains still question, how the landscape structure reflects the individual socio-economic predictors. To answer this question we compared landscape structure, with emphasis on non-forest woody vegetation, of two states, however, with common socio-economic and political history. Non-forest woody vegetation represents characteristic feature in rural landscape, which increases water retention, biodiversity and bio-migration using green structures. In our study we supposed, that non-forest woody vegetation will have high sensitivity to societal changes and nature conservation measures. On an example of border region in former Czechoslovakia we compared three classes of non-forest woody vegetation (solitaires, patches and linear elements) in three time horizons (1950, 1986, 2011). The most significant differences in spatial structure of non-forest woody vegetation between countries were in the number and area of solitaires, which decreased during the entire period. However, the largest solitaire decrease was in 1950-1986, mainly in correspondence with socialist collective farming. Moreover, the decrease was higher in the Slovak part compared to the Czech part. The primary reason for this was the removal of non-forest woody vegetation on one side and the joining crowns into bigger patches on the other side. The current trend of increasing area of patch and linear elements is related to natural succession. We assume that the main drivers of different development in non-forest woody vegetation in the border region after the split of Czechoslovakia were different management measures applied in nature and landscape conservation and social development.

ASIP disruption via CRISPR/Cas9 system induces black patches dispersion in Oujiang color common carp

Pigment pattern formation in economical fish remains elusive to date. Oujiang color common carp (Cyprinus carpio var. color) is a variant of common carp with different pigmentation patterns and important farm fish in China. Agouti signaling protein (ASIP) is an endogenous antagonist of melanocortin in the melanogenesis pathway. In this study, two ASIP genes (ASIP 1 and ASIP 2) were first identified in color common carp. Their expression was higher in the pale belly than in the dark dorsal skin, which was consistent with the typical dorsal–ventral expression pattern such as that of wild common carp. In comparison, an unusually higher expression was detected in the non-melanophore side skin than in the melanophore side skin of Oujiang color common carp. Thus, CRISPR/Cas9 was used to disrupt the two ASIP genes in Oujiang color common carp of red with big black patches (RB) pattern. Consequently, the black patches disappeared and the melanophores dispersed along the dorsal skin in the F0 mosaic RB individuals. The findings of this study indicate that the ASIP gene is involved in regulating melanin aggregation and distribution during black patch formation in Oujiang color common carp.

Assembly of trivalent particles under confinement: from an exotic solid phase to a liquid phase at low temperature.

Using computer simulations, we study the phase diagram of a two-dimensional system of disk particles with three patches distributed symmetrically along the particle equator. The geometry of the particles is compatible with a honey-comb lattice at moderately low temperature and pressure, whereas it is expected that the system forms a close-packed triangular lattice at high temperature and pressure. The effect of patch size within the single bond per patch regime was investigated, and it was found that the topology of the phase diagram changes drastically with patch size. Interestingly, in particles with small patches (with a half opening angle of 10°), the fluid transforms upon increasing the pressure into a rather exotic phase that can be understood as a honey-comb lattice whose voids are filled continuously with additional particles that remain, on average, unbound. Eventually, all the voids are occupied so that particles are located at the positions of a triangular lattice, but only two thirds of the particles are orientationally ordered whereas the remaining one third can rotate almost freely as in a plastic crystal. At moderately low temperature, the fluid transforms into a nearly empty honey-comb lattice, whereas at high temperature it transforms directly into the almost filled lattice. Interestingly, for particles with big patches (with a half opening angle of 20°), the honey-comb and triangular lattices are separated by a liquid phase that remains stable down to fairly low temperatures. Less surprisingly, only particles with big patches exhibit an equilibrium gas-liquid separation.

Surfactants for Bubble Removal against Buoyancy.

The common phenomenon of buoyancy-induced vapor bubble lift-off from a heated surface is of importance to many areas of science and technology. In the absence of buoyancy in zero gravity of space, non-departing bubbles coalesce to form a big dry patch on the heated surface and heat transfer deteriorates despite the high latent heat of vaporization of water. The situation is worse on an inverted heater in earth gravity where both buoyancy and surface tension act upwards to oppose bubble removal. Here we report a robust passive technique which uses surfactants found in common soaps and detergents to avoid coalescence and remove bubbles downwards, away from an inverted heater. A force balance model is developed to demonstrate that the force of repulsion resulting from the interaction of surfactants adsorbed at the neighboring liquid-vapor interfaces of the thin liquid film contained between bubbles is strong enough to overcome buoyancy and surface tension. Bubble removal frequencies in excess of ten Hz resulted in more than twofold enhancement in heat transfer in comparison to pure water. We believe that this novel bubble removal mechanism opens up opportunities for designing boiling-based systems for space applications.

Field performance of hand-mixed and machine-mixed asphalt in labour-based asphalt maintenance works

Asphalt premix for labour-based maintenance works can be produced manually (hand-mixed) or by mechanised asphalt plants – the conventional method. Hand-mixed asphalt (HDMA), common especially in most developing countries, is claimed to equal machine-mixed asphalt (MMA) in terms of durability. Recently, however, there have been concerns about reduced durability of labour-based asphalt (LBA) works. The current study compared durability of HDMA and MMA with a view to establish suitable scope and appropriate traffic conditions for LBA maintenance works. The study was based on laboratory tests – on binder, aggregate and site premix – and field experiments which involved asphalt production and placement of small and big patches of HDMA and MMA on a heavily trafficked Likuni Road and a lightly trafficked Tsiranana Avenue in Lilongwe, Malawi. The study monitored the patch durability for two months after the maintenance work. Effects of the study variables – production method (HDMA and MMA), scope of works (small and big patches) and road category (heavily trafficked and lightly trafficked roads) – on patch durability were statistically analysed. The study has shown that production method affects durability of LBA the most. HDMA had 67% less durability than MMA. Scope of works and road class affected LBA durability by 27% and 23%, respectively. At a level of significance (p-value) of 0.05, the effect of production method was significant, while that of patch size and work scope was not statistically significant. It is imperative of asphalt producers to adhere to proportions of premix components if quality of HDMA is to improve. Apart from improving the HDMA production process, the quality of LBA works could be improved by increasing contractors’ access to MMA. The study recommends contractors’ cooperation and adoption of production techniques (cost-cutting techniques) such as use of recycled asphalt pavement and warm mixture asphalts in order to improve contractors’ access to MMA.

Gene dispersal inference across forest patches in an endangered medicinal tree: comparison of model-based approaches

Propagule dispersal in plants is a fundamental mechanism for colonizing new sites and adapting to changing climates, as well as for maintaining genetic diversity. Contrasting past and current gene dispersal can provide useful insights to gauge the extent of recent human disturbances and guide management strategies. However, research on gene dispersal of plants is not yet exhaustive because evolutionary or environmental impacts are often species-specific and most existing studies have focused on analysis of dispersal at a single site, which may not be helpful for landscape-level inferences and management interventions. In the present study, we assessed whether current gene or propagule dispersal would be more restricted than past gene dispersal at multiple patches of the endangered medicinal tree, Prunus africana. We employed eight highly polymorphic microsatellite markers in conjunction with isolation-by-distance, spatial genetic structure (SGS), and parentage assignment models to estimate gene dispersal distance in a spatial extent of approximately 400 km2. There was no significant difference between gene dispersal distances across the different models (Friedman chi-squared = 7.286, d.f. = 5, P = 0.2002). Estimates of current gene dispersal distance were comparable to dispersal in the last few generations. However, gene dispersal distance was much shorter in smaller than bigger forest patches. Further, significant (P < 0.05) SGS was detected in most forest patches, with the extent of SGS among adults being stronger in the smaller than bigger patches. These results suggest the need for practicing enrichment plantings in most forest patches, particularly in the smaller ones, to assist gene exchange among individuals and patches. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114, 887–904.

1960－2010年广西红树林空间分布演变机制分析

PDF HTML阅读 XML下载 导出引用 引用提醒 1960-2010年广西红树林空间分布演变机制 DOI: 10.5846/stxb201401160119 作者: 作者单位: 广西林业勘测设计院 南宁 530011,广西林业勘测设计院 南宁 530011 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(41166001);中央财政林业科技推广示范资金(GXTG200904);UNEP-GEF-SCS-防城港红树林国际示范区 Mechanism analysis of temporal dynamics in mangrove spatial distribution in Guangxi, China: 1960-2010 Author: Affiliation: Guangxi Forest Inventory and Planning Institute Nanning 530011,China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为全面摸清1960-2010年广西红树林空间分布及其演变机制,采用多源遥感数据提取不同年度的红树林空间分布信息,分析了广西红树林空间分布动态特点,采用基于斑块的红树林空间演变机理分析方法,研究了1960/1976-2010年广西红树林空间演变机制。结果表明:1960/1976年、1990s年、2001年、2007年和2010年广西红树林斑块数量分别为1020、829、1094、1718个和1712个,面积分别为9062.5、7430.1、7015.4、6743.2、7054.3 hm2,近50年间红树林面积减少了22.16%,年均减少0.53%,斑块数量增加了67.8%;斑块平均面积由1960/1976年的8.9 hm2减小至2010年的4.1 hm2,大斑块数量显著减少,斑块破碎化严重;不同时期、不同区域和海湾,红树林面积和斑块数量的变化量、变化速率均不同;1960/1976年的斑块中,只有24个斑块至2010年时尚保持稳定,占2.4%,绝大部分斑块都发生了某种程度的变化。进一步分析结果表明:1960/1976-2010年,斑块消失(46.1%)、碎化(40.4%)、萎缩(13.5%)是面积减少的主要途径,新增(70.0%)和碎化(29.9%)是斑块数量增加的主要途径,但在不同时期,斑块数量和面积在各个途径上发生的变化量不尽相同;养殖塘和盐田建设(80.0%)、工程建设(10.9%)和围垦(9.1%)是面积净减少的驱动因子,自然过程(92.6%)和人工造林(7.4%)是斑块数量净增加的驱动因子,不同驱动因子在不同时期对斑块数量和面积变化的影响程度不同;斑块数量变化主要由自然过程作用下通过新增(39.6%)、消失(-9.1%)两个途径,以及养殖塘和盐田作用下通过消失(-15.3%)、碎化(14.5%)两个途径发生,斑块面积变化主要由自然过程影响下通过新增(17.5%)、扩张(12.6%)、消失(-6.1%),以及养殖塘和盐田建设驱动下通过斑块消失(-14.8%)、碎化(-13.9%)、萎缩(-6.6%)3个途径发生。 Abstract:Mangrove ecosystems are important for socioeconomic development and environmental protection but are experiencing sharp declines around the world. Asia has the most mangroves in area around the world but also has the largest human populations that threaten the ecosystem. Where mangrove is distributed and how its range changes are important topics for research throughout the world. Although many efforts have been made to study mangrove, more detailed information is still needed for better managing and protecting mangrove ecosystems. To analyze the mechanism of spatial dynamics of mangrove in Guangxi Beibu Gulf, China, from 1960 to 2010, multi-source remote sensing data were used to extract spatial information on mangroves in various years. The spatial distribution characteristics were analyzed and the spatial dynamic mechanisms of mangroves from 1960/1976 to 2010 were analyzed with a patch-based method. The results indicated that there were 1020, 829, 1094, 1718, and 1712 patches of mangrove in 1960/1976, 1990s, 2001, 2007, and 2010, respectively, and the areas were 9062.5, 7430.1, 7015.4, 6743.2, and 7054.3 hm2 in these 5 years, respectively. The region lost 22.16% of its mangrove area from 1960/1976 to 2010, with an annual loss rate of 0.53%. In the meantime, the patch-number increased 67.8%; the average patch-area decreased from 8.9 hm2 in 1960/1976 to 4.1 hm2 in 2010, and the number of big patches became smaller over time. Only 24 of 1020 patches (2.4%) in 1960/1976 remained unchanged till 2010, almost all the patches had changed to a certain degree. The results also indicated that lost (46.1%), fragmented (40.4%), and shrunken (13.5%) mangroves were the major components of the loss in mangrove area, whereas new (70.0%) and fragmented (29.9%) patches of mangrove were the main reasons for patch-number increases from 1960/1976 to 2010. The dynamics of patch-number and area changes varied both spatially and temporally. Shrimp and salt pond construction (80.0%), infrastructure construction (10.9%), and agriculture (9.1%) were the major causes of mangrove loss, and incensement of patch-number was due to natural processes (92.6%) such as extreme weather, flooding, sediment deposition, and growth/succession and plantations (7.4%) The causes of lost area varied both spatially and temporally. Changes in patch-number were mainly due to the natural processes and procedures of new patch (39.6%) and disappeared (-9.1%), and shrimp and salt pond construction and procedures of disappeared (-15.3%) and fragmented (14.5%); changes in mangrove areas were caused mainly by natural processes acted on the new (17.5%), expanded (12.6%), and disappeared (-6.1%) patches; shrimp and salt pond construction contributed to the disappeared (-14.8%), fragmented (-13.9%), and shrunken (-6.6%) mangrove patches. This study demonstrates the effectiveness of methodology that integrates natural processes and human activities into analysis of mangrove spatial distribution and its changes over time, and such a method can be used for in-depth mangrove research in other regions of the world. 参考文献 相似文献 引证文献