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GravityCam is a new concept of ground-based imaging instrument capable of delivering significantly sharper images from the ground than is normally possible without adaptive optics. Advances in optical and near-infrared imaging technologies allow images to be acquired at high speed without significant noise penalty. Aligning these images before they are combined can yield a 2.5–3-fold improvement in image resolution. By using arrays of such detectors, survey fields may be as wide as the telescope optics allows. Consequently, GravityCam enables both wide-field high-resolution imaging and high-speed photometry. We describe the instrument and detail its application to provide demographics of planets and satellites down to Lunar mass (or even below) across the Milky Way. GravityCam is also suited to improve the quality of weak shear studies of dark matter distribution in distant clusters of galaxies and multiwavelength follow-ups of background sources that are strongly lensed by galaxy clusters. The photometric data arising from an extensive microlensing survey will also be useful for asteroseismology studies, while GravityCam can be used to monitor fast multiwavelength flaring in accreting compact objects and promises to generate a unique data set on the population of the Kuiper belt and possibly the Oort cloud.
With an estimated < 50 adult individuals remaining, the Critically Endangered Balkan lynx Lynx lynx balcanicus is one of the rarest, most threatened and least-studied large carnivores. To identify priority conservation areas and actions for the subspecies, during 2006–2014 we conducted 1,374 questionnaire surveys throughout the potential range of the Balkan lynx to (1) evaluate human–lynx interactions and identify potential threats, and (2) determine the probability of site use in 207 grid cells through occupancy modelling. Human–lynx interactions were related mainly to poaching of lynx, and damage to livestock by lynx. Poaching was intense throughout the potential range of the subspecies, apparently having affected 50–100% of the total estimated extant population. Damage to livestock was recorded only in relation to sheep, mainly in the southern part of the lynx's potential range. Occupancy modelling indicated 108 grid cells with high probability of site use, which was affected mainly by increased terrain ruggedness and reduced forest cover. Based on the combined results of our study we identified five priority areas for conservation, as well as in situ habitat protection, community participation in the conservation of the subspecies, and the improvement and implementation of the existing legal framework as the priority conservation actions for the Balkan lynx.
For a prime
be a finitely generated free pro-
-group of rank at least
. We show that the second discrete homology group
is an uncountable
-vector space. This answers a problem of A. K. Bousfield.
Herein, we show that scanning probe microscopy (SPM) is an effective tool permitting to disclose the nature of the colossal dielectric permittivity characteristic of CaCu3Ti4O12 (CCTO) compound. SPM data confirm the existence of micro- and nanoscale barrier layer capacitance mechanisms which simultaneously contribute to the electrical conductivity of the material. The former mechanism is associated with the potential grain-to-grain barriers. The latter mechanism involves the barriers created by intragrain structural defects. The results of the SPM study shed new light on the origin of the colossal dielectric constant in CCTO.
Species that belong to the Aphidius eadyi group have been used as biocontrol agents against Acyrthosiphon pisum worldwide. However, despite their extensive use, there are still gaps in our knowledge about their taxonomy and distribution. In this study, we employed an integrative taxonomic approach by combining genetic analyses (mtDNA COI barcoding) with standard morphological analyses and geometric morphometrics of forewing shape. We identified three species within the A. eadyi species group, viz., A. smithi, A. eadyi and A. banksae. Genetic separation of all three species was confirmed, with mean genetic distances between species ranging from 5 to 7.4%. The following morphological characters were determined as the most important for separating species of the A. eadyi group: number and shape of costulae on the anterolateral part of the petiole, shape of the central areola on the propodeum, and shape and venation of the forewings. The differences in wing shape of all three species were statistically significant, but with some overlapping. We identified A. banksae as a widely distributed pea aphid parasitoid, whose known range covers most of the western Palaearctic (from the UK to Israel). Aphidius banksae is diagnosed and redescribed.
“There are almost as many different constructions of M24 as there have been mathematicians interested in that most remarkable of all finite groups”.
In this book the study of the Mathieu group M24 (and other Mathieu groups it contains) falls within the scope of what E. E. Shult called the Ivanov– Shpectorov theory of geometries. This theory has been developed to construct and identify large sporadic simple groups including the Baby Monster, the Fourth Janko Group J4 and the Monster. The most dramatic outcome of the theory was the proof of the famous Y -presentation conjecture for the Monster, which for a long time remained unobtainable by use of the other techniques. In the case of M24 the way in which the theory develops can be projected onto the familiar structures of the Steiner system on 24 points and the Golay code, thus presenting a bold illustration of the theory as well as providing a fresh look at familiar, nearly classical structures. I am extremely grateful to Madeleine Whybrow, William Giuliano and the anonymous referees for suggesting thoughtful corrections, clarifications and modifications after reading earlier versions of the book.
The Mathieu groups have many fascinating and unusual characteristics and have been studied at length since their discovery. This book provides a unique, geometric perspective on these groups. The amalgam method is explained and used to construct M24, enabling readers to learn the method through its application to a familiar example. The same method is then used to construct, among others, the octad graph, the Witt design and the Golay code. This book also provides a systematic account of 'small groups', and serves as a useful reference for the Mathieu groups. The material is presented in such a way that it guides the reader smoothly and intuitively through the process, leading to a deeper understanding of the topic.