Patch Structure Research Articles

Paisajes en transición: gradientes urbano-rurales y antropización del bosque templado andino del sur de Chile

La asignación de categorías espaciales arbitrarias en los análisis de paisaje es un factor limitante al interpretar procesos socio-ecológicos que ocurren de forma continua en el paisaje. La noción de gradiente urbano-rural se ha utilizado para sortear dicho límite. En este trabajo analizamos la relación entre la estructura de los parches de vegetación nativa y el grado de antropización del paisaje en una cuenca del sur de Chile, con relación a la distancia a la ciudad. Se utilizaron 14 transectos para testear la disposición en gradientes de la antropización utilizando el Índice de Hemerobia, métricas de paisaje y topogra-fía. Los resultados presentaron gradientes de intervención antrópica y de dominancia de clases en base a la distancia del centro urbano. Se distinguen tres secciones asociadas a una dominancia del área urbana, un sector de transición y de la clase bosque. Las transiciones del gradiente son la base para la vinculación entre patrones espaciales, procesos socio-ecológicos e intervención antrópica.

Multi-Forked Microstrip Patch Antenna for Broadband Application

In this paper, a new design simulation of multi-forked microstrip patch antenna is presented. The proposed antenna design consists of rectangular patch structure loaded multi-slotted forked with Arlon AD320A (tm) dielectric, direct coaxial probe feed technique, and microstrip edge feed, the novel forked shaped patch. The composite effect of integrating these multi-shapes forked patches techniques and by introducing the new multi-slotted patch.The best result of proposed antennas was a wide impedance bandwidth of 114 % at 10.31 GHz resonance frequency for microstrip line feed approach, and maximum achievable gain is 6.3 dB for coaxial probe feed approach. The return loss, directivity gain, and voltage standing wave ratio are simulated results using HFSS 13.0 software.

Broadband Stacked Antenna Design with Hybrid Structure for C-band Communication

Two low profile antennas using FR4 and Rogers RT/duroid 5880 as dielectric materials are proposed in this manuscript. To obtain the broadband response the strip-slot hybrid structure is introduced. The two antennas proposed in this manuscript consist of four strips that are segregated through three narrow tapered slots. Using the aperture couple microstrip feed line proper impedance matching is obtained and the slotted patch structure is excited. The simulated bandwidth of 45% is obtained by using the Rogers RT/duroid 5880 as dielectric material with stacked patch structure and gain obtained to be 9.02dB resonating at 4.2GHz of frequency. Proposed design using FR4 as the dielectric material has two resonance frequencies at 4.8GHz and 6.2GHz. The simulated bandwidth of 50% at 4.8GHz and 38.71% at 6.2GHz is obtained with gain of 6.040dB at 4.8GHz. A prototype of the same antenna using the FR4 as dielectric material is also constructed and tested, the tested results shows an impedance bandwidth of 21.87%

Video anomaly detection and localization via multivariate gaussian fully convolution adversarial autoencoder

In this paper, we present a novel deep learning based method for video anomaly detection and localization. The key idea of our approach is that the latent space representations of normal samples are trained to accord with a specific prior distribution by the proposed deep neural network - Multivariate Gaussian Fully Convolution Adversarial Autoencoder (MGFC-AAE), while the latent representations of anomalies do not. In order to extract deep features from input samples as latent representations, a convolutional neural network (CNN) is employed for the encoder of the deep network. Based on the probability that the test sample is associated with the prior distribution, an energy-based method is applied to obtain its anomaly score. A two-stream framework is utilized to integrate the appearance and motion cues to achieve more comprehensive detection results, taking the gradient and optical flow patches as inputs for each stream. Besides, a multi-scale patch structure is put forward to handle the perspective of some video scenes. Experiments are conducted on three public datasets, results verify that our framework can accurately detect and locate abnormal objects in various video scenes, achieving competitive performance when compared with other state-of-the-art works.

Spatial patch structure and adaptive strategy for desert shrub of Reaumuria soongorica in arid ecosystem of the Heihe River Basin

In many arid ecosystems, vegetation frequently occurs in high-cover patches interspersed in a matrix of low plant cover. However, theoretical explanations for shrub patch pattern dynamics along climate gradients remain unclear on a large scale. This context aimed to assess the variance of the Reaumuria soongorica patch structure along the precipitation gradient and the factors that affect patch structure formation in the middle and lower Heihe River Basin (HRB). Field investigations on vegetation patterns and heterogeneity in soil properties were conducted during 2014 and 2015. The results showed that patch height, size and plant-to-patch distance were smaller in high precipitation habitats than in low precipitation sites. Climate, soil and vegetation explained 82.5% of the variance in patch structure. Spatially, R. soongorica shifted from a clumped to a random pattern on the landscape towards the MAP gradient, and heterogeneity in the surface soil properties (the ratio of biological soil crust (BSC) to bare gravels (BG)) determined the R. soongorica population distribution pattern in the middle and lower HRB. A conceptual model, which integrated water availability and plant facilitation and competition effects, was revealed that R. soongorica changed from a flexible water use strategy in high precipitation regions to a consistent water use strategy in low precipitation areas. Our study provides a comprehensive quantification of the variance in shrub patch structure along a precipitation gradient and may improve our understanding of vegetation pattern dynamics in the Gobi Desert under future climate change.

Periodicity on Nicholson’s blowflies systems involving patch structure and mortality terms

ABSTRACTIn this paper, we investigate a class of delayed Nicholson’s blowflies systems with patch structure and nonlinear density-dependent mortality terms. By using differential inequality approach and Lyapunov function method, some criteria are established for the existence, uniqueness and exponential stability of positive periodic solutions for the addressed systems. Finally, we give a numerical example to illustrate the effectiveness and feasibility of the obtain results.

Bird Species Richness in Relation to Land-Use Patch Structure and Vegetation Structure in a Forest-Agriculture Mosaic

Habitat degradation and fragmentation are serious threats to global biodiversity. Attributes of vegetation structure and patch structure have been considered critical factors in sustaining species diversity, but their relative importance remains unclear. This study aimed at identifying key vegetation and patch structure variables for bird species richness and examining their relative importance. We surveyed and mapped all individual birds in a 50-ha forest-farm landscape mosaic over three breeding seasons and recorded the vegetation in 286 patches of six land-use types. Native forests and conifer plantations (covering 59% of the area) contained 89% of the individuals and all of the bird species recorded. The effects of vegetation structure variables, tree family richness, and foliage coverage were more significant than those of patch-structure variables. Although conifer plantations were low in tree family richness of the canopy layer, they had a high tree family richness in the sub-canopy layer, and had similar bird density and species richness values as native forests. Creating and maintaining patches with a complex vegetation structure are critical for supporting animal abundance and species diversity. Forest patches dominated by only a few tree species in the canopy layer can be greatly improved by increasing the floristic composition of the sub-canopy layer. Large patches with a complex vegetation structure are important for sustaining biodiversity and should be kept as intact as possible.

Multi-Forked Microstrip Patch Antenna for Broadband Application

In this paper, a new design simulation of multi-forked microstrip patch antenna is presented. The proposed antenna design consists of rectangular patch structure loaded multi-slotted forked as a novel shaped of the patch, with Arlon AD320A (tm) dielectric. The coaxial probe feed technique and microstrip edge feed are used as a direct feed. The composite effect of integrating these multi-shapes forked patches techniques introducing the new multi-slotted patch. The best results of the proposed antennas were a wide impedance bandwidth which is 114% at 10.31 GHz resonance frequency for the microstrip line feed approach and maximum achievable gain is 6.3 dB for the coaxial probe feed approach. The simulated results of return loss, radiation patterns, and voltage standing wave ratio are obtained by using the finite element HFSS 13.0 software

Effect of Lentinan on Peyer's patch structure and function in an immunosuppressed mouse model

Lentinan (LNT), a polysaccharide isolated from Lentinus edodes, has been shown to stimulate immune response. Despite its widespread use owing to its health benefits, epidemiologic and experimental studies that address the biological activities of LNT after oral administration to animals or humans are rare. In this study, the effects of LNT on the intestinal mucosal immune system of immunosuppressed mice were investigated. The number and size of the Peyer's patches (PPs), proliferation ability of PP lymphocytes, T and B lymphocyte percentage, and T-cell activation proportion, as well as the number of M-like cells in PPs, were determined. The antigen transfer ability of M-like cells and intestinal secretory immunoglobulin A (IgA) levels were also detected. After oral administration of LNT for 7 days, the number of PPs, lymphocytes in PPs, and the level of intestinal soluble IgA in immunosuppressed mice were increased. LNT maintained the percentage of T and B lymphocytes and upregulated the proportion of activated T cells in PPs. Furthermore, the number of M-like cells, which were differentiated from intestinal epithelial cells, and their antigen transfer ability were enhanced. These results indicate that orally administered LNT can improve the immune status of the intestinal mucosa in immunosuppressed mice.

Combining multi-state species distribution models, mortality estimates, and landscape connectivity to model potential species distribution for endangered species in human dominated landscapes

Species ranges are changing in response to human-related disturbances and often management and conservation decisions must be based on incomplete information. In this context, species distribution models (SDMs) represent the most widely used tool, but they often lack any reference to demographic performance of the population under study, spatial structure of the habitat patches, or connectivity at the landscape level.Combining a multi-state SDM with a landscape pattern analysis and a mortality model, we developed a spatially-explicit, integrated model to assist and inform conservation planning for the Apennine brown bear in central Italy. We identified 15 critical habitat areas, potentially hosting 76 adult female bears. Many of these areas are, however, characterized by high levels of human-related mortality, making them attractive sink-like areas. Structural connectivity was higher in the northern part of the study area while only limited connectivity characterizes the core area, where most of the bears currently live.Our integrated model indicates that the conservation of this relict and isolated bear population is a realistic conservation goal, as we estimated that 192–270 bears could live across the Apennines. Our modelling framework enhances the biological realism of traditional SDMs and provides a conservation planning tool that integrates habitat suitability, mortality risk (as a component of the total demographic performance) and structural connectivity among habitat patches at the landscape scale. It is particularly suited for endangered species living in a human-modified landscapes where establishing a realistic and spatially explicit conservation goal would facilitate pro-active management.

Grazing‐induced patchiness, not grazing intensity, drives plant diversity in European low‐input pastures

Abstract Livestock grazing at low stocking rates is widely recommended to maintain grassland biodiversity. However, empirical evidence of grazing‐intensity effects on plant diversity is contradictory. Explicitly considering the small‐scale heterogeneity of short, frequently grazed and tall, rarely grazed patches typical of low‐input grazing systems may be crucial to the understanding of paddock‐scale grazing effects. We studied three patch types (short, intermediate, tall) within an unfertilised long‐term cattle grazing experiment in Lower Saxony, Germany, comparing three paddock‐scale grazing intensities. We analysed soil nutrient concentrations and recorded vegetation composition at a total of 135 plots. We determined species richness, Simpson diversity, Simpson evenness and beta diversity of individual plots (plot scale) and patch types within paddocks (patch scale). To quantify paddock‐scale diversity, we resampled plot‐scale species composition across a gradient of relative proportions of short and tall patches within a paddock. Patch type, not paddock‐scale grazing intensity, was the main driver of plant diversity at both plot and patch scale. Short patches were more diverse than tall patches, but the effect was not strongly mediated by the lower soil nutrient concentrations in the short patches. By contrast, both patch type and grazing intensity affected vegetation composition at plot and patch scale. Beta‐diversity within and between patch types was independent of grazing intensity; consequently, paddock‐scale diversity was determined by the relative proportion of short versus tall patches. Higher alpha diversity of short patches compared to tall patches was more important than beta diversity between the two patch types in shaping paddock‐scale diversity. Consequently, with increasing short‐patch proportion, paddock‐scale diversity increased. Synthesis and applications. Our study identifies the grazing‐induced patch structure as the most important driver of plant diversity across different grazing intensities in low‐input, that is, unfertilised and continuously stocked, pastures. To optimise grazing management for biodiversity, understanding plant‐diversity responses to grazing at the patch scale is indispensable. Our results suggest that, in unfertilised, continuously stocked European pastures, trade‐offs between biodiversity and agronomic production may be small, as short patches, whose proportion increases with stocking rate, also had the highest plant diversity.

Using GIS-linked Bayesian Belief Networks as a tool for modelling urban biodiversity

The ability to predict spatial variation in biodiversity is a long-standing but elusive objective of landscape ecology. It depends on a detailed understanding of relationships between landscape and patch structure and taxonomic richness, and accurate spatial modelling. Complex heterogeneous environments such as cities pose particular challenges, as well as heightened relevance, given the increasing rate of urbanisation globally. Here we use a GIS-linked Bayesian Belief Network approach to test whether landscape and patch structural characteristics (including vegetation height, green-space patch size and their connectivity) drive measured taxonomic richness of numerous invertebrate, plant, and avian groups. We find that modelled richness is typically higher in larger and better-connected green-spaces with taller vegetation, indicative of more complex vegetation structure and consistent with the principle of ‘bigger, better, and more joined up’. Assessing the relative importance of these variables indicates that vegetation height is the most influential in determining richness for a majority of taxa. There is variation, however, between taxonomic groups in the relationships between richness and landscape structural characteristics, and the sensitivity of these relationships to particular predictors. Consequently, despite some broad commonalities, there will be trade-offs between different taxonomic groups when designing urban landscapes to maximise biodiversity. This research demonstrates the feasibility of using a GIS-coupled Bayesian Belief Network approach to model biodiversity at fine spatial scales in complex landscapes where current data and appropriate modelling approaches are lacking, and our findings have important implications for ecologists, conservationists and planners.

Patchiness in old-growth oriental beech forests across development stages at multiple neighborhood scales

The patch mosaic–development stage model posits the unity of patches and development stages in primeval temperate forests and links patchiness to the synchronized, coarse-scale canopy senescence, and breakup processes that initiate the demographic transition to new regeneration patches that then asynchronously progress through sequential development stages. Subtle structural differences and inconsistent transitions among development stages observed in primeval forests such as Oriental beech (Fagus orientalis Lipsky) set expected coarse-scale canopy senescence against observed, predominantly fine-scale canopy-gap dynamics. Applying a multi-scale approach to quantify the extent to which stages are characterized by the interspersion of neighborhoods of variously sized trees (i.e., patch types), we investigated patchiness and structural differences in nine Oriental beech stands classified into Initial, Optimum, and Decay stages. Differences among stages in patch type richness and composition occurred primarily at the finest scales and diminished rapidly with increasing scale. Most patch types were ubiquitous and the few patch types unique to a particular stage occurred at very low abundances. Patch types composed of advance regeneration were most prevalent in the Initial stage, but were absorbed into the matrix structure at scales > 500 m2. In all three stages, the most heterogeneous patch type encompassed > 90% of all trees at scales > 100 m2. To portray fine-scale dynamics resulting in similar patch type compositions and structures across development stages, we introduce and discuss the new patch mosaic–gap reabsorption model that avoids the unity of patch and “demographic” stage to focus instead on “structural” stages.

Thermal Benefits From White Variegation of Silybum marianum Leaves.

Leaves of the spiny winter annual Silybum marianum express white patches (variegation) that can cover significant surface areas, the outcome of air spaces formed between the epidermis and the green chlorenchyma. We asked: (1) what characterizes the white patches in S. marianum and what differs them from green patches? (2) Do white patches differ from green patches in photosynthetic efficiency under lower temperatures? We predicted that the air spaces in white patches have physiological benefits, elevating photosynthetic rates under low temperatures. To test our hypotheses we used both a variegated wild type and entirely green mutants. We grew the plants under moderate temperatures (20°C/10°C d/n) and compared them to plants grown under lower temperatures (15°C/5°C d/n). The developed plants were exposed to different temperatures for 1 h and their photosynthetic activity was measured. In addition, we compared in green vs. white patches, the reflectance spectra, patch structure, chlorophyll and dehydrin content, stomatal structure, plant growth, and leaf temperature. White patches were not significantly different from green patches in their biochemistry and photosynthesis. However, under lower temperatures, variegated wild-type leaves were significantly warmer than all-green mutants – possible explanations for that are discussed These findings support our hypothesis, that white variegation of S. marianum leaves has a physiological role, elevating leaf temperature during cold winter days.

A high capacity tunable retransmission type frequency coded chipless radio frequency identification system

This article presents a 12-bit frequency coded chipless RFID system in the frequency range of 3 to 6 GHz. The system consists of a fully printable chipless tag and a pair of high-gain reader antennas. The tag also incorporates its own antennas to improve the read range. Information is encoded into frequency spectrum using a multi-resonant circuit. The circuit consists of multiple microstrip U and L-shaped open stub resonators patterned in a unique configuration. The proposed configuration aids in capturing more data in a reduced space as well as tunable frequency operation. Tag and reader antennas utilize techniques such as stepped impedance feeding line, defective partial ground plane, and stair-step patch structure to achieve wide-band impedance bandwidth in miniature size. The results of the wireless measurements in the non-anechoic environment show that the proposed system has a reading range of more than 20 cm. The presented system possesses great potential for low-cost short-range inventory tracking.

Pseudo almost periodic dynamics of Nicholson’s blowflies model with patch structure and discontinuous harvesting

In this paper, a class of Nicholson’s blowflies model with patch structure and discontinuous harvesting terms is concerned. Some sufficient criteria are established for the existence, uniqueness and exponential convergence of positive pseudo almost periodic solutions of the model. The working tools are based on the contraction mapping principle, the theory of exponential dichotomy and Lyapunov functions. Moreover, an example is presented to illustrate the main findings.

Woody islands in South Brazilian coastal grasslands: effects of spatial variations on the structure of plant communities

Brazilian costal sand plains (restingas) are widely known for their many vegetation types, often responding to small landform variations which in turn cause quite distinct soil conditions. One interesting and still poorly known physiognomy is the woody patches or islands dispersed over sparse to dense herbaceous matrixes. Our main objective in this paper was to assess how spatial variables, as area and volume of the patches, affect the floristic composition and the community structure of woody patches in south Brazilian coastal grasslands. We analyzed 48 woody patches in four study sites in central coastal Rio Grande do Sul, Brazil. Each woody island was measured, and all vascular plant species above 30 cm were registered and quantified according to an abundance scale. Each species received values from one to five depending on the occurrence in five possible segments of each woody patch. Woody patches varied roughly between 4 and 204 m2. The floristic inventory resulted in 102 species in 49 families, Myrtaceae and Bromeliaceae being the most diversified, with eight and seven species, respectively. A total of 12 life-forms were recognized, the most diversified being trees or potential trees (27 species), herb–subshrub (17), climbers (20), and epiphytes (15). Species richness increased significantly with the size of woody islands, corroborating one of the basic premises of Theory of Island Biogeography. Diversity and abundance of life-forms in the contrary were not significantly different along the different sizes. The comparison of all woody islands from the four study sites indicated a higher similarity within each site, suggesting regional variation in soil properties, past disturbances, or landscape contexts.

Analysis of stochastic Nicholson-type delay system with patch structure

This paper is devoted an investigation of a stochastic Nicholson-type delay system with patch structure, which includes the models of marine protected areas and B-cell chronic lymphocytic leukemia dynamics all affected by some stochastic perturbation. Firstly, we prove that the system has a unique global positive solution by constructing a suitable Lyapunov functional. Then we show that the system is ultimately bounded in probability and the average in time of the second moment of solution is bounded. Furthermore, we give asymptotic pathwise estimation of the solution under some conditions. Finally, numerical simulations confirm the theoretical results. Our results improve and generalize previous related results.

Local temperature changes in the mesosphere due to a “horizontally propagating” turbulent patch

In this study, we model thermal changes in the background atmosphere due to a horizontally” moving” turbulent patch. We divide the process of mutual adjustment of the turbulent patch and the background atmosphere into the two stages: (i) Fast high-to-low transition of the atmospheric stability within the turbulent patch induced by strong adiabatic mixing within the “moving” turbulent patch. (ii) Slow adjustment of the ambient background atmosphere to a quasi-stabilized, near-adiabatic thermal stratification within the turbulent patch. Within the framework of the first stage, assuming the existence of a background downward heat flux, we developed a boundary value problem for a non-homogeneous heat equation that accounts for turbulent dissipative heating and mixing. This two-point boundary value problem was solved analytically by applying the Fourier method (separation of variables) to the thickness of the turbulent patch. The solution obtained tends towards equilibrium as the distance from the front border of the “moving” turbulent patch increases. Within the scope of the second stage, we solved the problem of thermal coupling of the two heat-transfer domains, one of which is characterized by a high coefficient of heat transfer. Solving this problem is the basis of our proposing that the thermal structure of a turbulent patch does not change under the influence of an ambient atmosphere, while the ambient atmosphere is cooled slowly above the turbulent patch and warmed slowly below it. Consequently, it is shown that the model temperature profiles demonstrate the same features as those observed in mesospheric inversion layers (MILs): temperature inversions and a near-adiabatic lapse rate between them.

Fractal Sierpinski Square Patch Antenna for GPS Applications

The high demand of a miniature antenna for wireless applications, motivates the researchers to design special types of microstrip antenna such as fractal Sierpinski. Fractal Sierpinski antenna based on square patch structure is proposed, designed and simulated to operate at resonance frequency at 1.575 GHz for GPS applications. Antenna Simulation is done using CST Studio suite version-2014. The proposed antenna is simulated on Sierpinski carpet shaped substrate Arlon 250 AD lossy of dielectric constant equals to 2.5 and thickness of 1.6 mm. The thickness of patch is 0.6 mm. The results are reported in terms of reflection coefficient, VSWR, directivity and gain. According to the results, the fractal of 3rditeration exhibits good properties that it possesses gain of 7.79 dB and VSWR is 1.6. Significant reduction of antenna area can be realized when fractal Sierpinski carpet patch antenna is used instead of conventional antenna. Reduction area of 3rd iteration is about 36% less than 0th iteration. The results highlight that antenna becomes more efficient by applying fractal geometry.