Characterization of preclones by matrix collections

Preclones are described as the closed classes of the Galois connection induced by a preservation relation between operations and matrix collections. The Galois closed classes of matrix collections are also described by explicit closure conditions.Comment: 11 page

SMART - Sediment Mitigation Actions for the River Rother, UK

The River Rother, West Sussex, is suffering from excess sediment which is smothering the river bed gravels. This is thought to be exacerbating issues of pollution and degradation of ecosystems. This project aims to identify the severity, extent, possible causes and potential mitigation options available to reduce these pressures on the river. Data have been collected from ten sites to investigate the amount of sediment stored in the river bed gravels and cores obtained from four small reservoirs to establish rates of sedimentation and contribute to the construction of a temporal sediment budget over the last 50–100 years. Evidence suggests that tributary streams have more stored sediment per m2 upstream of their confluence with the River Rother compared to the Rother itself. Reservoir core data indicate that sediment has accumulated more rapidly in the small reservoirs surrounded by mixed agricultural land compared to one surrounded by ancient woodland. These are preliminary results and work is continuing

Monitoring and assessing land degradation: new approaches

This chapter examines land degradation in southern Africa. The focus is on the major issue of erosion by water at scales ranging from a few square metres to assessments that aim to cover the whole region. Approaches to measure and reconstruct both current and historical erosion rates are considered, focusing on the period since the arrival of Europeans who brought many of their farming and management practices with them. In most parts of the country, the impact of humans on the landscape has been clear for the last 200 years. This is referred to as ’accelerated erosion’, i.e., erosion at rates that are above the natural geological norm for the current climatic conditions. The chapter considers a range of techniques including direct measurement, remote sensing, fingerprinting and modelling as approaches to the monitoring and assess land degradation

Gyrotropic impact upon negatively refracting surfaces

Surface wave propagation at the interface between different types of gyrotropic materials and an isotropic negatively refracting medium, in which the relative permittivity and relative permeability are, simultaneously, negative is investigated. A general approach is taken that embraces both gyroelectric and gyromagnetic materials, permitting the possibility of operating in either the low GHz, THz or the optical frequency regimes. The classical transverse Voigt configuration is adopted and a complete analysis of non-reciprocal surface wave dispersion is presented. The impact of the surface polariton modes upon the reflection of both plane waves and beams is discussed in terms of resonances and an example of the influence upon the Goos–Hänchen shift is given

Nonlinear surface waves in left-handed materials

We study both linear and nonlinear surface waves localized at the interface separating a left-handed medium (i.e. the medium with both negative dielectric permittivity and negative magnetic permeability) and a conventional (or right-handed) dielectric medium. We demonstrate that the interface can support both TE- and TM-polarized surface waves - surface polaritons, and we study their properties. We describe the intensity-dependent properties of nonlinear surface waves in three different cases, i.e. when both the LH and RH media are nonlinear and when either of the media is nonlinear. In the case when both media are nonlinear, we find two types of nonlinear surface waves, one with the maximum amplitude at the interface, and the other one with two humps. In the case when one medium is nonlinear, only one type of surface wave exists, which has the maximum electric field at the interface, unlike waves in right-handed materials where the surface-wave maximum is usually shifted into a self-focussing nonlinear medium. We discus the possibility of tuning the wave group velocity in both the linear and nonlinear cases, and show that group-velocity dispersion, which leads to pulse broadening, can be balanced by the nonlinearity of the media, so resulting in soliton propagation.Comment: 9 pages, 10 figure

INITIAL EVALUATION OF CYCLIC ADENOSINE MONOPHOSPHATE ENZYME IMMUNOASSAY FOR USE WITH CRANE SEMEN SAMPLES

The management of ex situ and in situ populations of many wildlife species requires detailed knowledge of a species’ reproductive biology. For species such as cranes, where artificial insemination is a critical component of ex situ management strategies, understanding normal sperm function is especially important. Previous research has shown that captive cranes exhibit highly variable production and quality of semen samples produced by individual males and high levels of variation of cell concentration and motility across different species. Cyclic adenosine monophosphate (cyclic AMP) has been implicated in regulating sperm function, such as cell motility, and may affect an individual’s ability to successfully fertilize. Here we demonstrate the feasibility of an enzyme-linked immunosorbent assay (ELISA) for measuring cyclic AMP produced by crane sperm to facilitate future research into its role in sperm function and fertilization

Cold treatment enhances low-temperature flight performance in false codling moth, Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

1 In sterile insect technique programmes, temperatures experienced by insects during rearing and handling, along with cool temperatures after release, can negatively affect performance and activity levels. Phenotypic plasticity (trait modifications caused by prior stress exposure) can offset these effects but is poorly understood in many species and traits. 2 We investigated the effects of a cold treatment (2 ∘C for 16 h) on flight performance in adult false codling moth, Thaumatotibia leucotreta. Using diverse methods, flight performance was tested using flight assays in the laboratory and in the field under varying environmental conditions. 3 The flight performance of T. leucotreta in the laboratory was affected by cold treatment (relative to a 25 ∘C control group), test temperature and their interaction. Field recapture of released moths was significantly affected by the interaction between cold treatment and environmental conditions. 4 Field recapture counts depended on the ambient temperature upon release. For example, under warmer conditions (>17 ∘C), the recapture count of cold-treated moths was lower than that of the untreated control group, whereas the recapture count of cold-treated moths at cooler temperatures was significantly higher. 5 Our results suggest a temperature-dependent interaction between acute cold exposure and flight performance in adult T. leucotreta, which may be used to enhance the efficacy of the sterile insect technique under cooler environmental conditions

Next generation of land system science: Integrating meso-scale analysis and UAS remote sensing in changing plant communities of the United States' Southern Great Plains

As concerns about desertification, climate change, economic pressures, and reductions in global biodiversity become more prevalent, so too does the importance of research in the socio-ecological resilience of dryland agricultural communities. Cimarron County, Oklahoma and Union County, New Mexico have historically faced cyclical drought and land degradation as a challenge to agriculture. More recently, the expansion of woody plant species in rangelands threatens to destabilize grassland communities, limit forage for cattle, and reduce water resources. This thesis uses a Land System Science (LSS) approach to study how vegetation communities have changed in the two counties across multiple scales. By utilizing household surveys with ranchers, ground-level biodiversity and rangeland health assessments, unmanned aerial systems (UAS/drone) imagery, and satellite-based remote sensing, a holistic, integrative picture of the interrelated factors affecting woody plant encroachment (WPE) is presented. Household surveys indicated that agriculturalists are keenly aware of nuisance species on their property, with many taking actions to reduce their abundance. Woody species cited by landowners including one-seed juniper, Great Plains yucca, broom snakeweed, and cane cholla were reliably detected and identified to species level through ground and UAS observations. While there was strong agreement in land-cover estimates between the two methods, ground observations were more useful in measuring herbaceous species biodiversity while UAS was advantageous in surveying woody species across larger areas. WPE was affected by land-use factors, and was more severe in grazed pastures. By contrast, WPE was less severe on Conservation Reserve Program lands and plots with prior herbicide applications. Environmental factors also played a role, with greater WPE vulnerability in areas of rugged terrain, sandy soils, and cooler, drier climates. While LSS research has a history of using both field observations and satellite remote sensing to connect "people to pixels," the present investigation demonstrates of the utility of UAS imagery as a powerful bridge in scale. As studies in land systems evolve and become more important, UAS is poised to serve as a potential rapid assessment method which can provide context and additional detail to coarser- or finer-scale analyses