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In areas of induced seismicity, earthquakes can be triggered by stress changes due to fluid injection and static deformation from fault slip. Here we present a method to distinguish between injection‐driven and earthquake‐driven triggering of induced seismicity by combining a calibrated, fully coupled, poroelastic stress model of wastewater injection with interpretation of a machine learning algorithm trained on both earthquake catalog and modeled stress features. We investigate seismicity from Paradox Valley, Colorado as an ideal test case: a single, high‐pressure injector that has induced thousands of earthquakes since 1991. Using feature importance analysis, we find that injection‐driven earthquakes are approximately 22± $\pm $5% of the total catalog but act as background events that can trigger subsequent aftershocks. Injection‐driven events also have distinct spatiotemporal clustering properties with a larger b‐value, closer proximity to the well, and earlier occurrence in the injection history. Generalization of our technique can help characterize triggering processes in other regions where induced seismicity occurs. Plain Language Summary: The Paradox Valley Unit, Colorado in the central United States has had a remarkable increase in seismicity coincident with over 8 million cubic meters of brine fluid injection since 1991, inducing thousands of earthquakes within an aquifer 4.5 km below the surface. We use a physics‐based model of the Earth combined with statistical and machine learning techniques to help discern which earthquakes are triggered by other earthquakes and which earthquakes are directly triggered by the stress changes from the well as well as their comparative characteristics. Discerning which earthquakes are directly caused from pressure changes due to the fluid injected by the well can inform our understanding of earthquake physics and provide useful information to operators of energy production sites. Key Points: Physics‐based models with interpretable machine learning can identify likely triggering mechanism of earthquakes within an induced sequenceWith this technique, we show that only 22土5% of earthquakes in Paradox Valley are primarily injection‐drivenInjection‐driven events have a larger b‐value, are closer to the well, and occur earlier in the injection history [ABSTRACT FROM AUTHOR]

A new quantitative method, the D-index, is proposed to evaluate the departure of a given fibre arrangement from the completely spatial randomness (CSR) pattern. An explicit model which can effectively control the degree of randomness (DoR) is created to investigate the correlation between the D-index and DoR. The theory behind the correlation is analyzed followed by the derivation of first and higher order D-index with respect to the DoR under different fibre volume fractions. This may be the first time an accurate value of the departure from randomness is provided, which is considered important for accurate micro-mechanical analysis.

In recent years, the status of ecotourism in mass tourism has gradually increased, among which the grassland ecotourism market is booming. The study uses data mining techniques to extract POI data for grassland ecotourism in Hulunbeier City. The mined POI data of grassland ecotourism in Hulunbeier City are analyzed by using nearest-neighbor distance index analysis, multi-distance spatial clustering, kernel density estimation, standard deviation ellipse, and geodetector model to explore the spatial agglomeration characteristics of grassland ecotourism in Hulunbeier City, the grassland tourism development pattern, and the influencing factors of grassland ecotourism. Accordingly, the sustainable development of grassland tourism in Hulunbuir City is proposed. The nearest neighbor index (NNI) value of grassland tourism in Hulunbuir City is 0.64 (less than 1), and the NNI index of the 13 flags (cities and districts) under the jurisdiction of Hulunbuir City is less than 1, which indicates that the grassland tourism industry is characterized by agglomeration and distribution within the city of Hulunbuir. The grassland ecotourism industry in Hulunbuir City presents a spatial distribution pattern of “multi-core agglomeration” with large agglomeration and small dispersion. The high-density cores are located in New Barkhu Left Banner, Manzhouli, Hailar District, Chenbalhu Banner, and Ergunar City. There are eight subdivided types of grassland tourism development patterns in Hulunbeier City. The four major categories of single dominant, double dominant, strong integrated, and weak integrated accounted for 34.11%, 23.55%, 7.09%, and 35.25% of the total, respectively. The spatial distribution of tourism in Hulunbeier Grassland is more influenced by natural geographic factors than socio-economic factors.

Outlier detection is part of data editing phase for numerical variables. This work investigates outlier detection in the R environment by comparing “traditional” methods, popular in official statistics, with techniques developed in the field of data mining and statistical learning. The comparison is done considering longitudinal data where a set of quantitative non-negative variables are observed twice (or more) on the same sample of units. The work attempts to identify some “recent” outlier detection methods, already available in the R environment, that seem suitable for application in official statistics. This study takes stock of findings of a previous work investigating outlier detection in the univariate case that showed the goodness of some “recent” approaches; in this article we go a step further and investigate the behavior of “traditional” and recent methods also in the multivariate case. The first preliminary results are quite interesting and useful as guidance towards application of the chosen methods in the production of official statistics using the R facilities. [ABSTRACT FROM AUTHOR]

We report here studies of the regularity of the distribution of ganglion cells in the high-resolution zones of the retina of a neonatal and an adult bottlenose dolphin Tursiops truncatus. Two indicators were used as regularity criteria: the statistical distribution of the distances from each cell to the nearest neighboring cell (nearest neighbor distance, NND distribution) and the density of surrounding cells around each cell as a function of distance (spatial autocorrelogram, SACG). NND distributions for retinal cells in both neonatal and adult animals differed from the distribution for a random array of points, which is taken as an indication that the arrangement of cell is regular. Distributions were similar in neonatal and adult animals. SACG for the retinas of both neonatal and adult animals differed from the autocorrelogram for a random array of points in that each cell was surrounded by a "well," the zone in which other cells were sparse or absent. This differed from the SACG of a random array of points, and hence another indication that the arrangement of cells is regular. The radius of the zone lacking neighboring cells was greater in the adult animal than the neonate, indicating that cells were more regularly arranged in the adult than the neonate. The absence of differences in NND distributions in neonatal and adult animals is understandable on the basis that this indicator is less informative than SACG. It is suggested that development of the spatial organization of the retina in dolphins is not complete at birth, but continues during postnatal ontogeny. This development consists of continuing ordering of the relative positions of ganglion cells. [ABSTRACT FROM AUTHOR]

We derive analytic expressions of Helmholtz free energy, crystal parameters, nearest neighbor distance and mean nearest neighbor distance between two atoms, volume and equation of state of metal and substitutional alloy with FCC structure on the basis of the statistical moment method. We perform numerical calculations of density and ratio of volume at pressure P to volume at zero pressure for metals Al, Cu and substitutional alloy AlCu at temperature up to 1500 K and pressure up to 350 GPa when using the Mie–Lennard–Jones n − m potential and the coordination sphere method. Our calculation results are compared with the experimental data, other theoretical calculations and molecular dynamics simulations. [ABSTRACT FROM AUTHOR]

Time series analysis is quickly proceeding towards long and complex tasks. In recent years, fast approximate algorithms for discord search have been proposed in order to compensate for the increasing size of the time series. It is more interesting, however, to find quick exact solutions. In this research, we improved HOT SAX (Heuristically Ordered Time series using Symbolic Aggregate ApproXimation) by exploiting two main ideas: the warm-up process, and the similarity between sequences close in time. These improvements can reduce the size of the discord search space by orders of magnitude when compared with HOT SAX. The resulting algorithm, called HOT SAX Time (HST), has been validated with real and synthetic time series, and successfully compared with HOT SAX, RRA (Rare Rule Anomaly), SCAMP (SCAlable Matrix Profile), and DADD (Disk Aware Discord Discovery). The complexity of a discord search has been evaluated with a new indicator, the cost per sequence (cps), which allows one to compare searches on time series of different lengths. Numerical evidence suggests that two conditions are involved in determining the complexity of a discord search in a non-trivial way: the length of the discords, and the noise/signal ratio. This is the first exact discord search algorithm that has been demonstrated being more than 100 times faster than HOT SAX. [ABSTRACT FROM AUTHOR]

Recently, generalizations of the classical Three Gap Theorem to higher dimensions attracted a lot of attention. In particular, upper bounds for the number of nearest neighbor distances have been established for the Euclidean and the maximum metric. It was proved that a generic multi-dimensional Kronecker attains the maximal possible number of different gap lengths for every sub-exponential subsequence. We mirror this result in dimension d ∈ {2, 3} by constructing Kronecker sequences which have a surprisingly low number of different nearest neighbor distances for infinitely N ∈ ℕ. Our proof relies on simple arguments from the theory of continued fractions. [ABSTRACT FROM AUTHOR]

The occupancy model (OM) was proposed to explain how the spatial arrangement of dots in sparse random patterns affects their perceived numerosity. The model's central thesis maintained that each dot seemingly fills or occupies its surrounding area within a fixed radius ro and the total area collectively occupied by all the dots determines their apparent number. Because the perceptual system is not adapted for the precise estimation of area, it looks likely that the OM is just a convenient computational algorithm that does not necessarily correspond to the processes that actually take place in the perceptual system. As an alternative, the proximity model (PM) was proposed, which instead relies on a binomial function with the probability β characterizing the perceptual salience with which each element can be registered by the perceptual system. It was also assumed that the magnitude of β is proportional to the distance between a dot and its nearest neighbor. A simulation experiment demonstrated that the occupancy area computed according to the OM can almost perfectly be replicated by the mean nearest neighbor distance. It was concluded that proximity between elements is a critical factor in determining their perceived numerosity, but the exact algorithm that is used for the measure of proximities is yet to be established. [ABSTRACT FROM AUTHOR]

Neurons are commonly organized as regular arrays within a structure, and their patterning is achieved by minimizing the proximity between like-type cells, but molecular mechanisms regulating this process have, until recently, been unexplored. We performed a forward genetic screen using recombinant inbred (RI) strains derived from two parental A/J and C57BL/6J mouse strains to identify genomic loci controlling spacing of cholinergic amacrine cells, which is a subclass of retinal interneuron. We found conspicuous variation in mosaic regularity across these strains and mapped a sizeable proportion of that variation to a locus on chromosome 11 that was subsequently validated with a chromosome substitution strain. Using a bioinformatics approach to narrow the list of potential candidate genes, we identified pituitary tumor-transforming gene 1 (Pttg1) as the most promising. Expression of Pttg1 was significantly different between the two parental strains and correlated with mosaic regularity across the RI strains. We identified a seven-nucleotide deletion in the Pttg1 promoter in the C57BL/6J mouse strain and confirmed a direct role for this motif in modulating Pttg1 expression. Analysis of Pttg1 KO mice revealed a reduction in the mosaic regularity of cholinergic amacrine cells, as well as horizontal cells, but not in two other retinal cell types. Together, these results implicate Pttg1 in the regulation of homotypic spacing between specific types of retinal neurons. The genetic variant identified creates a binding motif for the transcriptional activator protein 1 complex, which may be instrumental in driving differential expression of downstream processes that participate in neuronal spacing.

The aim of this work is to obtain a useful anomaly definition for online analysis of time series. The idea is to develop an anomaly concept which is sustainable for long-lived and frequent streamings. As a solution, we provide an adaptation of the discord concept, which has been successfully used for anomaly detection on time series. An online approach implies the frequent processing of a data streaming for timely providing anomaly alerts. This requires a modification since discord search is not exactly decomposable in its original definition. With a statistical approach, allowing to rate the significance of the discords of each analysis, it has been possible to obtain a solution where the number of false positives is minimized. The new online anomalies are called significant online discords (sods). As a novel feature, sod search determines the quantity of anomalies in the time series under investigation. The search for sods has been implemented and its properties validated with synthetic and real data. As a result, we found that sods can be considered as a useful new tool for anomaly detection in fast streaming time series or Big Data contexts. [ABSTRACT FROM AUTHOR]

ABSTRACT Weakly electric fishes continually emit electric organ discharges (EOD) as a means of communication and localization of objects in their surroundings. Depending on water conductivity, the amplitude of the electric field generated is known to increase with decreases in electrical conductivity of the water. In Amazonian terra firme streams, water conductivity is extremely low and fluctuates constantly due to local and regional rains. In this context, the space between freely moving weakly electric fishes may be expected to decrease, on average, with an increase in water conductivity. To test this hypothesis, we recorded the positions at rest of the sand-dwelling fish Gymnorhamphichthys rondoni in a terra firme stream for several days in alternating months, over two years. Based on daily nearest neighbor distances among individual fish in a grid, we found a uniform temporal distribution pattern (which was not affected by water conductivity) indicative of site fidelity. Here we highlight the role of other factors that could influence resting site fidelity.

Land use and coverage change (LUCC) is an important research field of global change. Currently, land use and coverage change research focuses on the analysis of land use structures during the same period, and structure changes in the overall quantity of land use between time-series periods. While, the study of quantitative analysis of land use evolution process in different periods is deficient, which results difficulty to profoundly reveal the temporal and spatial patterns and evolution laws that may exist in the process of land change. Therefore, in this paper, we proposed a spatiotemporal pattern analysis of land use change based on the spatiotemporal process of land use. In this paper, the spatiotemporal variation sequence data of land use was the study object. Firstly, the spatiotemporal variation sequence of land use intensity in the study area was extracted by the spatiotemporal network. Secondly, as the basic measurement tool, the cumulative value of land use intensity change (CVLUIC) of different spatiotemporal variation sequences of land use was calculated. Thirdly, the CVLUIC is divided into three grades by K-means clustering. Finally, the spatiotemporal clustering analysis of different land use change grades was carried out. From the global perspective, the spatiotemporal pattern of land use change process was measured by the nearest neighbor distance analysis method. On the other hand, based on Ripley's k function, the multi-scale impact of traffic network on land use temporal and spatial change patterns was analyzed. The results showed that the dramatic land use intensity change (Type I) and the gradual land use intensity change (Type III) over the 10-year period from 2008 to 2017 in the study area showed significant clustering characteristics. While, the spatiotemporal clustering characteristics of the more severe land use intensity change (Type II) between Type I and Type III was not significant, The results showed that the human disturbance activities have obvious spatiotemporal heterogeneity during the study period. Additionally, the traffic network had a strong influence on land use and coverage change. The three types of land use intensity were clustered in the range close to the traffic network (in the range of 300 m and 600 m), and tend to be randomly distributed in the farther distance (within 900 m), which showed that the transportation network had a strong impact on land use change. At different spatial scales from the transportation network, the dramatic land use intensity change (Type I) and the gradual land use intensity change (Type III) showed significant significance on the small spatial scale, while the more severe land use intensity change (Type II) at multiple scales was not significant. This indicated that there were scale differences in the impact of transportation network on spatial and temporal changes of land use degree, and more extreme land use change processes (Type I and Type III) were more likely to show spatial and temporal aggregation. Through analyzing the land use change from the perspective of the spatiotemporal evolution process, our work will be useful supplement to the LUCC research. [ABSTRACT FROM AUTHOR]

• Investigation of the interevent characteristics by the nearest neighbor distance method. • Distribution characteristics of real-time interval and real-space distance. • Correlation between the nearest neighbor distance and b-value, fractal dimension. Three-point-bending tests on notched concrete beams were performed with real-time AE (acoustic emission) monitoring. Based on the nearest neighbor theory modified from seismology, the minimum interevent distance η j * for every AE event is calculated. The b-value and space fractal dimension are computed to further explore the parameter η j *. The experimental results indicate that η j * values for AE data from three-point-bending tests show a mixed distribution of background and clustered events, similar to earthquakes induced by fluids, and are considered to be due to the formation of a single main fracture under this loading condition. The real-time difference and real-time interval for every nearest event pair are similar to the lognormal and exponential distributions, respectively. According to η j * combined with the spatial distribution of AE events, η j * is negatively correlated with the fracture trace, which means that AE events with smaller η j * values are closer to the trace. Analyses of b-values and spatial fractal dimensions illustrate η j * 's ability to smooth the variation curves of these two parameters and clarify their change rules. These observations confirm that η j * is a useful index for illustrating the interevent characteristics of AE data and has significance for analyzing the fracture mechanisms of concrete materials. [ABSTRACT FROM AUTHOR]

Weakly electric fishes continually emit electric organ discharges (EOD) as a means of communication and localization of objects in their surroundings. Depending on water conductivity, the amplitude of the electric field generated is known to increase with decreases in electrical conductivity of the water. In Amazonian terra firme streams, water conductivity is extremely low and fluctuates constantly due to local and regional rains. In this context, the space between freely moving weakly electric fishes may be expected to decrease, on average, with an increase in water conductivity. To test this hypothesis, we recorded the positions at rest of the sand-dwelling fish Gymnorhamphichthys rondoni in a terra firme stream for several days in alternating months, over two years. Based on daily nearest neighbor distances among individual fish in a grid, we found a uniform temporal distribution pattern (which was not affected by water conductivity) indicative of site fidelity. Here we highlight the role of other factors that could influence resting site fidelity. [ABSTRACT FROM AUTHOR]

The arrangement of plants within revegetated sites is rarely considered an important characteristic of these communities. However, in natural systems, plant spatial arrangements can influence a range of ecological processes, including pollination and seed set. Pollinators tend to preferentially visit larger and/or more closely spaced populations, with plants in these populations generally receiving more outcrossed pollen, resulting in increased seed set and better quality seed. Similar trends may occur in revegetated populations, but little is known about the influence of planting arrangement on seed production in restored systems. Here, we quantified the effect of plant abundance (number of conspecifics within 100 m) and distance to nearest reproductive conspecific on the level of seed set for six eucalypt species (n = 422 trees in total) in 1 year and for one of these species (Eucalyptus leucoxylon), across three additional years. Seed number per fruit was highly variable both between individuals and within individuals across years. Despite this variability, there was a consistent trend of higher seed production (seed number per fruit) when another reproductive conspecific was within 20 m. In contrast, plant abundance had little influence on seed production. Further investigation of nearest neighbor arrangements found the distance to either the first, second, third, or fourth reproductive neighbors were the key predictors of seed production. Therefore, revegetation designs that consider plant spacing and aggregation, rather than only planting to overall density criteria (i.e. trees/ha), at least for the eucalypts studied here, has the potential to improve seed production in revegetated populations. [ABSTRACT FROM AUTHOR]

The introduction of alien species could be changing food source composition, ultimately restructuring demography and spatial distribution of native communities. In Argentine Patagonia, the exotic European hare has one of the highest numbers recorded worldwide and is now a widely consumed prey for many predators. We examine the potential relationship between abundance of this relatively new prey and the abundance and breeding spacing of one of its main consumers, the Black-chested Buzzard-Eagle (Geranoaetus melanoleucus). First we analyze the abundance of individuals of a raptor guild in relation to hare abundance through a correspondence analysis. We then estimated the Nearest Neighbor Distance (NND) of the Black-chested Buzzard-eagle abundances in the two areas with high hare abundances. Finally, we performed a meta-regression between the NND and the body masses of Accipitridae raptors, to evaluate if Black-chested Buzzard-eagle NND deviates from the expected according to their mass. We found that eagle abundance was highly associated with hare abundance, more than with any other raptor species in the study area. Their NND deviates from the value expected, which was significantly lower than expected for a raptor species of this size in two areas with high hare abundance. Our results support the hypothesis that high local abundance of prey leads to a reduction of the breeding spacing of its main predator, which could potentially alter other interspecific interactions, and thus the entire community. [ABSTRACT FROM AUTHOR]

De-clustering the seismic catalog is one of the crucial processes in determining the probability of exceeding ground motions at particular locations. Removing dependent events, such as foreshocks and aftershocks generated from mainshocks, from an earthquake catalog is known as seismicity de-clustering. This paper presents a new approach to classify seismicity using a swarm intelligence technique called the memory-guided Aquila optimizer (MGAOA). Aquila optimization is a recently reported yet popular optimization algorithm inspired by the hunting process of Aquila. In MGAOA, the Aquila searches for the prey based on the personal best history stored in the memory element, which helps MGAOA to converge faster and maintain the balance between exploration and exploitation during local and global search procedures. The search-controlled parameter is further integrated with Aquila optimization to enhance the exploitation phase of the algorithm. The effectiveness of the proposed MGAO is tested on twenty-three classical test functions and ten benchmark test suites of IEEE CEC 2021. The results show that the proposed MGAOA outperforms other algorithms regarding performance metrics and statistical tests. The MGAOA is applied to solve the problem of seismicity de-clustering using the nearest neighbor distance (NND). The NND is a widely used parameter for seismicity and consists of space–time-magnitude information. The MGAOA-based de-clustering model is used to identify the seismic clusters in highly active earthquake-prone Himalayas, California, Japan, and Indonesia regions. The results obtained by the proposed model are compared with state-of-the-art de-clustering techniques and other memory-guided swarm intelligence techniques. The obtained results in terms of aftershocks and backgrounds are evaluated with the help of cumulative plot, λ -plot, space–time plot, inter-event time versus inter-event distance plot, and statistical parameters like coefficient of variance, which show that the proposed model efficiently detects the seismic clusters, and outperforms other benchmark de-clustering techniques. • A memory guided Aquila optimization algorithm (MGAOA) is proposed. • MGAOA performance is reported on 23 classical benchmark functions and 10 IEEE CEC 2021 test functions. • MGAOA model is developed to de-cluster seismicity of four earthquake regions using nearest neighbor distance. • Performance of proposed model is compared with five benchmark de-clustering algorithms. • Validation of proposed model is done using statistical and graphical representations. [ABSTRACT FROM AUTHOR]

The introduction of alien species could be changing food source composition, ultimately restructuring demography and spatial distribution of native communities. In Argentine Patagonia, the exotic European hare has one of the highest numbers recorded worldwide and is now a widely consumed prey for many predators. We examine the potential relationship between abundance of this relatively new prey and the abundance and breeding spacing of one of its main consumers, the Black-chested Buzzard-Eagle (Geranoaetus melanoleucus). First we analyze the abundance of individuals of a raptor guild in relation to hare abundance through a correspondence analysis. We then estimated the Nearest Neighbor Distance (NND) of the Black-chested Buzzard-eagle abundances in the two areas with high hare abundances. Finally, we performed a meta-regression between the NND and the body masses of Accipitridae raptors, to evaluate if Black-chested Buzzard-eagle NND deviates from the expected according to their mass. We found that eagle abundance was highly associated with hare abundance, more than with any other raptor species in the study area. Their NND deviates from the value expected, which was significantly lower than expected for a raptor species of this size in two areas with high hare abundance. Our results support the hypothesis that high local abundance of prey leads to a reduction of the breeding spacing of its main predator, which could potentially alter other interspecific interactions, and thus the entire community.

Risso's dolphin (Rissos; Grampus g behavior is little described given then-riseus) rvpical offshore distribution where research access is inherently challenging. We conducted focal group behavior follows of 51 Rissos groups from a circling, small, fixed-wing Partenavia aircraft in the Southern California Bight from 2008 through 2012 (15 aerial surveys; 72,647 km: 86 d).Instantaneous scan sampling of group heading and behavior state (rest/slow travel, medium-fast [mf]travel, and mill), and maximum nearest neighbor distance (MNND) estimated in adult body lengths(BLs) were noted once per 30 s. Focal follows occurred for 5 to 59 min (n = 51, mean 21.6, standard deviation [SD] = 12.9). Mean group size was 25.8(n = 51.SD±23.62.range3tol20).Atotalof 1,446 usable headings, 1,275 MNND, and 1,359 behavior state data points were used to calculate response variables of reorientation, splitting-joining, and behavior state transition rates relative to explanatory variables using standard multiple-linear-regression, logistic regression, or multi-linear-regressio nomial logistic regression models. Reorientation rates tended to be higher when other species were present. No explanatory variables were found to influence the splitting-joining rate. Rissos behavior state was significantly affected by calf presence and time of day. Rissos groups spent most (60%) time engaged in rest/slow travel followed by mf travel (33%) and milling (7%), and rarely changed behavior state. Transitions from one behavior state to another were more common in groups with calf presence, which were 4.3 times more likelv to continue mf travel than non-calf groups. During early afternoon. Rissos were six times more likelv to continue mf travel versus early morning and late afternoon. Preponderance of daytime rest/slow travel likely reflects presumed need for diurnal rest prior to apparent nocturnal foraging, a pattern associated with other nocturnal foraging dolphin species. Observations from aircraft facilitate a unique birds eye view on social interactions and spacing of individuals, which are less available from the low-vantage perspective of other platforms. [ABSTRACT FROM AUTHOR]

The pollination success of two nonrewarding orchids in two coarse habitats was examined. The comparative results of Orchis punctulata and O. purpurea showed a significant differentiation. The fruit set of O. purpurea was significantly greater compared to O. punctulata, whereas both species also had significantly higher fruit set in the grassland compared to the forest. Although the pollination success of O. purpurea was not significantly correlated with plant height, inflorescence size, or nearest neighbor distance, these factors were found to be significantly correlated to the pollination success of O. punctulata. Among these factors, the nearest neighbor distance had the highest impact on the pollination success of O. punctulata, whereas the respective effects to the individuals of O. purpurea were found to be nonsignificant. The results demonstrate that the distribution of O. punctulata at the edges of its range is not delimited by factors related to its pollination effectiveness and that other factors, mostly related to the microsite conditions, might play a more significant role in the colonization of more western areas. Moreover, suitable management treatments that would increase the light levels within the forest sites studied may also increase the pollination success and the fruit production of the studied orchids. [ABSTRACT FROM AUTHOR]

The introduction of alien species could be changing food source composition, ulti)mately restructuring demography and spatial distribution of native communities. In Argentine Patagonia, the exotic European hare has one of the highest numbers recorded worldwide and is now a widely consumed prey for many predators. We examine the potential relationship between abundance of this relatively new prey and the abundance and breeding spacing of one of its main consumers, the Black-chested Buzzard-Eagle (Geranoaetus melanoleucus). First we analyze the abundance of individuals of a raptor guild in relation to hare abundance through a correspondence analysis. We then estimated the Nearest Neighbor Distance (NND) of the Black-chested Buzzard-eagle abundances in the two areas with high hare abundances. Finally, we performed a meta)regression between the NND and the body masses of Accipitridae raptors, to evaluate if Black-chested Buzzard-eagle NND deviates from the expected according to their mass. We found that eagle abundance was highly associated with hare abundance, more than with any other raptor species in the study area. Their NND deviates from the value expected, which was significantly lower than expected for a raptor species of this size in two areas with high hare abundance. Our results support the hypothesis that high local abundance of prey leads to a reduction of the breeding spacing of its main predator, which could potentially alter other interspecific interactions, and thus the entire community. [ABSTRACT FROM AUTHOR]

Stomata distribution is an example of biological patterning. Formal methods used to study stomata patterning are generally based on point-pattern analysis, which assumes that stomata are points and ignores the constraints imposed by size on the placement of neighbors. The inclusion of size in the analysis requires the use of a null model based on finite-size object geometry., In this study, we compare the results obtained by analyzing samples from several species using point and disc null models., The results show that depending on the null model used, there was a 20% reduction in the number of samples classified as uniform; these results suggest that stomata patterning is not as general as currently reported. Some samples changed drastically from being classified as uniform to being classified as clustered. In samples of Arabidopsis thaliana, only the disc model identified clustering at high densities of stomata., This reinforces the importance of selecting an appropriate null model to avoid incorrect inferences about underlying biological mechanisms. Based on the results gathered here, we encourage researchers to abandon point-pattern analysis when studying stomata patterning; more realistic conclusions can be drawn from finite-size object analysis. [ABSTRACT FROM AUTHOR]

Since the entropy is a popular randomness measure, there are many studies for the estimation of entropies for given random samples. In this paper, we propose an estimation method of the Rényi entropy of order α . Since the Rényi entropy of order α is a generalized entropy measure including the Shannon entropy as a special case, the proposed estimation method for Rényi entropy can detect any significant deviation of an ergodic stationary random source’s output. It is shown that the expected test value of the proposed scheme is equivalent to the Rényi entropy of order α . After deriving a general representation of parameters of the proposed estimator, we discuss on the particular orders of Rényi entropy such as α → 1 , α = 1 / 2 , and α = 2 . Because the Rényi entropy of order 2 is the most popular one, we present an iterative estimation method for the application with stringent resource restrictions.

Modeling the random fiber distribution of a fiber-reinforced composite is of great importance for studying the progressive failure behavior of the material on the micro scale. In this paper, we develop a new algorithm for generating random representative volume elements (RVEs) with statistical equivalent fiber distribution against the actual material microstructure. The realistic statistical data is utilized as inputs of the new method, which is archived through implementation of the probability equations. Extensive statistical analysis is conducted to examine the capability of the proposed method and to compare it with existing methods. It is found that the proposed method presents a good match with experimental results in all aspects including the nearest neighbor distance, nearest neighbor orientation, Ripley's K function, and the radial distribution function. Finite element analysis is presented to predict the effective elastic properties of a carbon/epoxy composite, to validate the generated random representative volume elements, and to provide insights of the effect of fiber distribution on the elastic properties. The present algorithm is shown to be highly accurate and can be used to generate statistically equivalent RVEs for not only fiber-reinforced composites but also other materials such as foam materials and particle-reinforced composites. [ABSTRACT FROM AUTHOR]

A new unsupervised feature selection algorithm, based on the concept of shared nearest neighbor distance between pattern pairs, is developed. A multi-objective framework is employed for the preservation of sample similarity, along with dimensionality reduction of the feature space. A reduced set of samples, chosen to preserve sample similarity, serves to reduce the effect of outliers on the feature selection procedure while also decreasing computational complexity. Experimental results on six sets of publicly available data demonstrate the effectiveness of this feature selection strategy. Comparative study with related methods based on different evaluation indices have demonstrated the superiority of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Phymactis clematis Drayton es la especie de actinia más abundante y unas de las que alcanza mayor tamaño en la costa de Sudamérica. Al igual que en otras especies de actinias, los adultos de la especie poseerían una activa capacidad de realizar desplazamientos locales. Sin embargo estos no han sido adecuadamente descritos, desconociéndose los factores causales. En este trabajo pretendemos describir algunos patrones básicos asociados a la conducta de desplazamiento local en P. clematis, evaluados indirectamente a partir de la presencia de halos de roca desnuda alrededor de los individuos en dos sitios intermareales rocosos en la costa del norte de Chile (Cavancha y Colorado Chico). Los desplazamientos fueron más frecuentes y de mayor intensidad en Colorado Chico, donde más del 50 % de los individuos evidenciaron desplazamientos, aunque generalmente no superaron los 60 mm de extensión. En Colorado Chico, los desplazamientos ocurrieron principalmente en individuos con diámetro pedal superior a 40 mm, mientras que la intensidad de éstos decrecería con el tamaño. Discutimos que las causas del mayor desplazamiento de individuos en Colorado Chico podrían estar asociadas a la mayor abundancia y menor espaciamiento entre los individuos, los cuales derivarían en una interferencia física entre los individuos. De este modo sugerimos que los patrones asociados al tamaño de los individuos emergerían secundariamente, siendo supeditados al nivel de abundancia local. A pesar de que los desplazamientos de P. clematis en Colorado Chico ocurren en general a una escala de unos pocos centímetros, tendrían un efecto significativo en el espaciamiento interindividual, incrementando en promedio la distancia al vecino más próximo. Se plantea la posibilidad de que los desplazamientos locales serían un mecanismo efectivo de reducción de la competencia intraespecífica en P. clematisPhymactis clematis Drayton is the most abundant and one of the largest species of sea anemone along the South American coast. Likewise other sea anemone species, the adults of the P. clematis would have an active ability to make local movements. However, these have not been properly described, and causal factors are unknown. In this work we try to describe some of the basic patterns associated to the local movement behavior in P. clematis, assessed indirectly from the presence of bare rock halos around individuals in two rocky intertidal sites in the coast of northern Chile (Cavancha and Colorado Chico). Movements were more frequent and had a higher intensity at Colorado Chico, where over 50 % of individuals showed movements, although they were mainly lower than 60 mm in length. At Colorado Chico, movements would occur in individuals larger than 40 mm of pedal diameter, whereas their intensity would decrease with body size. We discussed that causes of higher movement activity at Colorado Chico could be associated to the higher abundance and lower inter-individual spacing, which would produce physical interference among individuals. In this way, we suggested that the patterns associated to the individual's body size would arise secondarily, being dependent on the levels of local abundance. Despite local movements of P. clematis at Colorado Chico occurred at a scale of a few centimeters, they could be affecting significantly the inter-individual spacing, increasing the average nearest neighbor distance. We argue that local movements could be an effective mechanism reducing the intraspecific competition in P. clematis

The focus of our study was to create a Main Map of fire occurrence zones from historical wildland fire ignition observations at national level in Greece using a Kernel Density estimation procedure. Kernel density estimation, a non parametric statistical method for estimating probability densities, has been widely used for home range estimation in wildlife ecology. It has the advantage of directly producing density estimates that are not influenced by grid size and localization effects. Furthermore, it produces densities of any shape and analyzes any data distributed multi-modally or non-normally. Under this perspective, kernel density surfaces have been created to construct fire occurrence zones. Their observed distribution was statistically significantly different than the expected one that arises under complete spatial randomness. A smoothing effect is certainly observed when increasing the bandwidth size of the kernel density interpolation. Excluding the kernel size of 1000 meters, then the results do not prove any influence of kernel size or control points on the kernel density surfaces. [ABSTRACT FROM AUTHOR]

Abstract: This work presents a methodology for elaborating sinkhole hazard models that incorporate the magnitude and frequency relationships of the subsidence process. The proposed approach has been tested in a sector of the Ebro valley mantled evaporite karst, where sinkholes, largely induced by irrigation practices, have a very high occurrence rate (>50sinkholes/km2/yr). In this area, covering 10km2, a total of 943 new cover collapse sinkholes were inventoried in 2005 and 2006. Multiple susceptibility models have been generated analyzing the statistical relationships between the 2005 sinkholes and different sets of variables, including the nearest sinkhole distance. The quantitative evaluation of the prediction capability of these models using the 2006 sinkhole population has allowed the identification of the method and variables that produce the most reliable predictions. The incorporation of the indirect variable nearest sinkhole distance has contributed significantly to increase the quality of the models, despite simplifying the modeling process by using categorical rather than continuous variables. The best susceptibility model, generated with the total sinkhole population and the selected method and variables, has been transformed into a hazard model that provides minimum estimates of the spatial–temporal probability of each pixel to be affected by sinkholes of different diameter ranges. This transformation has been carried out combining two equations derived from the more complete 2006 sinkhole population; one of them expressing the expected spatial–temporal probability of sinkhole occurrence and the other the empirical magnitude and frequency relationships generated for two different types of land surfaces, which control the strength of the surface layer and the size of the sinkholes. The presented method could be applied to predict the spatial–temporal probability of events with different magnitudes related to other geomorphic processes (e.g. landslides). [Copyright &y& Elsevier]

Abstract: Manual grading process of Fresh Fruit Bunch (FFB) leads to misconduct and human error while inspecting the right category of fruits for the purpose of oil palm production at the mill. It is extremely important to identify the degree of ripeness of FFB are at 95% level of confidence as mentioned by Malaysian Palm Oil Board (MPOB). Therefore, wrong evaluation of graded fruits will result wrong report regarding the oil content. However, the most critical part of oil palm grading is the fruit classification. Error in classifying the right category of FFB will cause error in estimating the oil content. Research done by Federal Land Development Authority (FELDA) at mills show the estimated oil content for ripe fruit is 60%, while underripe is 40% and unripe is only 20% minus water and dirt. This indicates the importance of the right classification of FFB during grading process is essential to prevent from mistakenly claim low quality fruits as the good ones. Problem will occur while receiving the grading report claiming the high percentage of Basic Extraction Rate (BER) by the appointed graders while they have been proven to be poor quality fruits during oil production process. Fruit ripeness identification based on color is hard to measure especially when it involves the color intensity. The most suitable color space must be carefully selected to determine the right color especially when the color intensity is involved. HSV color space has proven to be a good choice because it has all the colors in the channel. Besides, it also offers color intensity which can be in variety level of intensity degrees. This paper explores the use of Nearest Neighbor Distance for histogram-based fruit ripeness identification. Promising results are obtained when value elements of HSV gives the highest recognition rate towards both ripe and unripe category. [Copyright &y& Elsevier]

The average distance between points of a fractal is proposed as a natural measure of the way in which the points of a fractal are distributed. The average distance between points of the Cantor Set is found to be $\frac{2}{5}$, the average distance between points of the Cantor p-set is $\frac{p+1}{p+3}$, and the average distance between points of the Fat Cantor p-set is $\frac{2}{3(2-p)}$. A general formula for computing the average distance between points of a self-similar set satisfying the open set condition is found. [ABSTRACT FROM AUTHOR]