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Estimating pest population size is of utmost importance in biological control. However field experiments can be difficult and expensive to conduct, with no guarantee that useable results will be produced. In this context, the development of mathematical models and numerical tools is crucial to improve the field experiments by suggesting relevant data which can be used to estimate parameters related to the pest’s biology and to the traps (e.g. duration of the experiments, distance of the releases, etc.). Here we develop a trap-insect model (TIM), based on coupled partial differential equations. The model is studied theoretically and a finite element algorithm is developed and implemented. A protocol for parameter estimation is also proposed and tested, with various data. Among other results, we show that entomological knowledge is absolutely necessary for efficient estimation of parameters, in particular population size.
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This paper presents the results of an investigation of early Holocene cryptotephra layers recovered from sediments in two kettle-hole basins at Inverlair (Glen Spean) and Loch Etteridge (Glen Fernisdale). Electron probe micro-analysis (EPMA) of shards from two cryptotephra layers revealed that the uppermost layer in both sequences has a composition similar to the An Druim tephra, first reported from a site in Northern Scotland. We present evidence that distinguishes the An Druim from the chemically very similar early Holocene Ashik tephra. The lowermost layer at Inverlair matches the composition of the Askja-S tephra found in the Faroe Islands, Ireland, Sweden, Germany and Switzerland. This is the first published record of the Askja-S tephra from mainland Scotland. As at other sites, the Askja-S seems to mark a short-lived climatic deterioration, most likely the Pre-Boreal Oscillation: at Inverlair it occurs just above an oscillation represented by a reduction in LOI values and in the abundance of Betula pollen, and by a peak in Juniperus pollen. The lowermost layer at Loch Etteridge has a Katla-type chemistry and extends through the upper part of the Loch Lomond (Younger Dryas/GS-1) Stadial to the Stadial/Holocene transition; it may represent a composite layer which merges the Vedde and Abernethy tephras. One of the key conclusions is that the glacial-melt deposits in the vicinity of Inverlair (kames and kame terraces) were ice-free by c. 10.83ka (the age of the Askja-S), providing a limiting age on the disappearance of LLR ice in Glen Spean.
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The construction of beaver dams facilitates a suite of hydrologic, hydraulic, geomorphic, and ecological feedbacks that increase stream complexity and channel–floodplain connectivity that benefit aquatic and terrestrial biota. Depending on where beaver build dams within a drainage network, they impact lateral and longitudinal connectivity by introducing roughness elements that fundamentally change the timing, delivery, and storage of water, sediment, nutrients, and organic matter. While the local effects of beaver dams on streams are well understood, broader coverage network models that predict where beaver dams can be built and highlight their impacts on connectivity across diverse drainage networks are lacking. Here we present a capacity model to assess the limits of riverscapes to support dam-building activities by beaver across physiographically diverse landscapes. We estimated dam capacity with freely and nationally-available inputs to evaluate seven lines of evidence: (1) reliable water source, (2) riparian vegetation conducive to foraging and dam building, (3) vegetation within 100m of edge of stream to support expansion of dam complexes and maintain large colonies, (4) likelihood that channel-spanning dams could be built during low flows, (5) the likelihood that a beaver dam is likely to withstand typical floods, (6) a suitable stream gradient that is neither too low to limit dam density nor too high to preclude the building or persistence of dams, and (7) a suitable river that is not too large to restrict dam building or persistence. Fuzzy inference systems were used to combine these controlling factors in a framework that explicitly also accounts for model uncertainty. The model was run for 40,561km of streams in Utah, USA, and portions of surrounding states, predicting an overall network capacity of 356,294 dams at an average capacity of 8.8dams/km. We validated model performance using 2852 observed dams across 1947km of streams. The model showed excellent agreement with observed dam densities where beaver dams were present. Model performance was spatially coherent and logical, with electivity indices that effectively segregated capacity categories. That is, beaver dams were not found where the model predicted no dams could be supported, beaver avoided segments that were predicted to support rare or occasional densities, and beaver preferentially occupied and built dams in areas predicted to have pervasive dam densities. The resulting spatially explicit reach-scale (250m long reaches) data identifies where dam-building activity is sustainable, and at what densities dams can occur across a landscape. As such, model outputs can be used to determine where channel–floodplain and wetland connectivity are likely to persist or expand by promoting increases in beaver dam densities.
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This paper describes program betaFIT, which performs least-squares fits of sets of one-dimensional (or radial) potential function values to four different types of sophisticated analytic potential energy functional forms. These families of potential energy functions are: the Expanded Morse Oscillator (EMO) potential [J Mol Spectrosc 1999;194:197], the Morse/Long-Range (MLR) potential [Mol Phys 2007;105:663], the Double Exponential/Long-Range (DELR) potential [J Chem Phys 2003;119:7398], and the “Generalized Potential Energy Function (GPEF)” form introduced by Šurkus et al. [Chem Phys Lett 1984;105:291], which includes a wide variety of polynomial potentials, such as the Dunham [Phys Rev 1932;41:713], Simons–Parr–Finlan [J Chem Phys 1973;59:3229], and Ogilvie–Tipping [Proc R Soc A 1991;378:287] polynomials, as special cases. This code will be useful for providing the realistic sets of potential function shape parameters that are required to initiate direct fits of selected analytic potential functions to experimental data, and for providing better analytical representations of sets of ab initio results.
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Effect of network reconfiguration on power quality issues of distribution system has been investigated. The problem of network reconfiguration is reformulated with an objective to improve the power quality of the distribution system. Along with the traditional objective of loss minimization, power quality related objectives such as minimization of harmonic distortion of the voltage waveform, minimization of voltage unbalances at the nodes and maximization of sag voltages are identified as the objectives of reconfiguration. Branch exchange technique has been used to establish each of the objectives. The problem has also been formulated as a multi-objective optimization problem. The multiple objectives are, however, incorporated into a single objective using weighting multipliers and branch exchange technique has been judicially applied to take care of all the objectives. It is found that network reconfiguration can be used as an effective tool to improve the power quality of distribution system. Besides, the distributed energy sources also have great impacts on distribution network, as their size and locations are found to have great importance on the power loss, voltage sag, voltage harmonic distortion and unbalance. The effectiveness of the network reconfiguration on power quality issues have been studied on 25-bus network and IEEE 33-bus network with and without presence of distributed generation and VAr sources.
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A new insect species (†Alienopterus brachyelytrus Bai, Beutel, Klass, Wipfler et Zhang gen. et sp. nov.) of a new order and family is described, based on a single male embedded in Cretaceous Burmese amber (ca. 99Ma). Unusual characters are shortened forewings combined with fully developed, operational hindwings, similar as in Dermaptera, and specialized attachment pads otherwise only found in mantophasmatodeans (heelwalkers). A cladistic analysis suggests a placement as sister to Mantodea, supported by a profemoral brush and other characters. The male genitalia show the same pattern in both groups. Specialized features are the unusual flight apparatus, attachment structures adapted for locomotion on leaves, and a dense profemoral setation suitable for catching small prey. †Alienopterus was apparently able to fly and likely a predator of small arthropods in bushes or trees. An impressive radiation of Mantodea started in similar habitats at least 35Ma later in the early Cenozoic. In contrast, †Alienopterus was an evolutionary dead end in the roach–mantis transition zone.
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The diagonal method (DM) is an innovative technique to obtain trustworthy survey data on an arbitrary categorical sensitive characteristic Y∗ (e.g., income classes, number of tax evasions). The estimation of the unconditional distribution of Y∗ from DM data has already been shown. Now, a covariate extension of the DM, that is, methods to investigate the dependence of Y∗ on nonsensitive covariates, is sought. For instance, the dependence of income on gender and profession may be under study. The covariate extensions of privacy-protecting survey designs are broadened by the covariate DM, especially because existing methods focus on binary Y∗. LR-DM estimation and stratum-wise estimation are described, where the former is based on a logistic regression model, leads to a generalized linear model, and requires computer-intensive methods. The existence of a certain regression estimate is investigated. Moreover, the connection between efficiency of the LR-DM estimation and the degree of privacy protection is studied and appropriate model parameters of the DM are searched. This problem of finding suitable model parameters is rarely addressed for privacy-protecting survey methods for multicategorical Y∗. Finally, the LR-DM estimation is compared with the stratum-wise estimation. MATLAB programs that conduct the presented estimations are provided as supplemental material.
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Since adequate information on the distribution of biodiversity is hardly achievable, biodiversity indicators are necessary to support the management of ecosystems. These surrogates assume that either some habitat features, or the biodiversity patterns observed in a well-known taxon, can be used as a proxy of the diversity of one or more target taxa. Nevertheless, at least for certain taxa, the validity of this assumption has not yet been sufficiently demonstrated.
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We report the second record of a grammitid fern from Dominican amber. The fossil comprises a single fertile pinna with excellent preservation, thus allowing a clear view of unaltered morphological characters. Venation, indument, and sori match the protologue of the previously described species from Dominican amber, Grammitis succinea L. D. Gómez, so we assign our fossil to that species. Characters of both specimens of G. succinea are sufficient to place it within the grammitid clade of the Polypodiaceae. However, it does not agree with Grammitis as it is currently circumscribed. We explore possible relationships between the fossil and other extant grammitid genera through Principal Coordinates Ordination (PCOa) of 109 morphological characters and through phylogenetic analysis of combined morphological and plastid DNA sequence data. Character combinations found in the fossil are inconsistent with those of any extant genus and our PCOa analysis did not suggest a clear affinity with any extant genus. This uncertainty is reflected in the results of our phylogenetic analyses, which find multiple most-parsimonious positions for the fossil within the grammitid clade. Based on these results, we suggest that the fossil belongs to an early divergent lineage of grammitid ferns, and cannot be assigned to any extant genus. Consequently, we place both specimens in a newly described fossil genus, Polymniopteris, and make a new combination for G. succinea within it. Because the type of G. succinea cannot be located, we designate the present specimen a neotype.
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Solid food disintegration within the stomach has a major role on the rate and final bioavailability of nutrients within the body. Understanding the link between food material properties and their behaviour during gastric digestion is key to the design of novel structures with enhanced functionalities. However, despite extensive research, the establishment of proper relationships has proved difficult. This work builds on the hypothesis that to bridge this knowledge gap a better understanding of the underlying mechanisms of food disintegration during digestion is needed. The purpose of this study is to propose a new protocol that, by uncoupling the physicochemical processes occurring during gastric digestion, allows for a more rigorous understanding of these mechanisms. Using steamed potatoes as a product model, this study aims to develop a viable methodology to characterize the role of gastric juice and compressive forces on the breakdown mechanics of solid foods during digestion. From a general viewpoint, this work not only reveals the importance of the parameter used to describe the size distribution of food particles on the interpretation of their breakdown behaviour, but also provides a new framework to characterize the mechanisms involved. Results also illustrate that food breakdown during gastric digestion might well not follow a unimodal behaviour, highlighting the need to characterize their performance based on parameters describing broad aspects of their particle size distribution rather than single point values. Arguably simplistic on its approach, this study illustrates how an improved understanding of the role of chemical and physical processes on the breakdown mechanics of solid foods can facilitate valid inferences with respect to their in-vivo performance during digestion. In particular, it shows that while the contraction forces occurring in the stomach can easily disintegrate the potato matrix at the molecular level, the continuous exposure to gastric juices will promote their disintegration into progressively smaller debris. A discussion on the challenges and future directions for the implementation of a more general and standardized protocol is provided. Not intended to reproduce the breakdown behaviour of foods during gastric digestion, but rather to characterize the mechanisms involved, the proposed protocol would open new opportunities to identify the material properties governing the performance of different foods upon ingestion.
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