647 research outputs found
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Flight behaviour and migration of insect pests: Radar studies in developing countries (NRI Bulletin 71)
The use of radar to make direct observations of insects flying at altitude has provided many new insights into the phenomenon of long-range insect migration. In particular, the technique has produced a wealth of quantitative information on the spatial and temporal distribution of migrants in the air, on the direction, speed and duration of their displacements, and on their orientation behaviour. These data could not have been obtained by any other means, and it is probably fair to claim that our present knowledge of the magnitude and importance of high altitude insect movement stems very largely from radar observations. The pioneering field studies using the first specially designed entomological radar were undertaken in 1968, with the support of the UK Overseas Development Administration (ODA), and since that time ODA has been responsible for funding almost all of the applications of the technique in developing countries. The motivation for this work was the assumption that it was impossible to design efficient management strategies for migrant pest insects without a good knowledge of their migratory behaviour, and of the role which this played in their population dynamics. The ODA-funded studies thus focused primarily on pest species, and were carried out by the Radar Entomology Unit of the Natural Resources Institute (NRI) and its precursors. In this Bulletin, we give a brief account of the history of radar entomology, with emphasis on studies of insect pests. Next, the different types of entomological radar and some associated analysis methods are outlined, together with descriptions of some ancillary measurement techniques. We then describe in some detail the contributions made by the NRI Radar Unit to current knowledge of the flight patterns of a variety of major insect pests of agriculture and of human health. These pests include: grasshoppers and locusts, the African Armyworm moth, the Rice Brown Planthopper and other rice pests, the Old World Bollworm, and some mosquito vectors of human diseases. Recent developments directed towards long-term monitoring of insect aerial faunas (for environmental impact, biodiversity and conservation purposes), and towards observations of low-altitude flight, are included. The Bulletin concludes with a short overview, in which we speculate how the technique might find application in the future
Sustaining Workflows and Budget: Using Zotero, SHERPA/RoMEO, and Unpaywall to Input Faculty Works
Charles C. Sherrod Library was tasked with inputting faculty works in the open access institutional repository, Digital Commons@East Tennessee State University (https://dc.etsu.edu). In order for this project to remain sustainable with limited staffing and funding, they created a workflow around the integration of Zotero and SHERPA/RoMEO to input data and check copyright in addition to Unpaywall to locate open access documents. This presentation will detail the technical aspects and workflow of using these freely available products so that attendees can replicate all or relevant parts of this project. After a year of using the products, Sherrod Library completed a quantitative study on the quality records available in Zotero based on disciplines and document types. The study discovered that the education and arts/humanities fields were poorly represented in contrast to the social/behavioral sciences and medicine/health sciences fields. Furthermore, journal articles, books, and book contributions were better represented in Zotero than newsletters and magazine articles, conference proceedings, and music albums. Consequently, Sherrod Library continues to use the products primarily for journal articles, books, and book contributions by STEM faculty. The outcomes of this study can inform content providers on how to best sustain open data through their websites’ structures and metadata practices
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Radar studies of the vertical distribution of insects migrating over southern Britain: the influence of temperature inversions on nocturnal layer concentrations
Insects migrating over two sites in southern UK (Malvern in Worcestershire, and Harpenden in Hertfordshire) have been monitored continuously with nutating vertical-looking radars (VLRs) equipped with powerful control and analysis software. These observations make possible, for the first time, a systematic investigation of the vertical distribution of insect aerial density in the atmosphere, over temporal scales ranging from the short (instantaneous vertical profiles updated every 15 min) to the very long (profiles aggregated over whole seasons or even years). In the present paper, an outline is given of some general features of insect stratification as revealed by the radars, followed by a description of occasions during warm nights in the summer months when intense insect layers developed. Some of these nocturnal layers were due to the insects flying preferentially at the top of strong surface temperature inversions, and in other cases, layering was associated with higher-altitude temperature maxima, such as those due to subsidence inversions. The layers were formed from insects of a great variety of sizes, but peaks in the mass distributions pointed to a preponderance of medium-sized noctuid moths on certain occasions
Some investigations into non passive listening
Our knowledge of the function of the auditory nervous system is based upon a wealth of data obtained, for the most part, in anaesthetised animals. More recently, it has been generally acknowledged that factors such as attention profoundly modulate the activity of sensory systems and this can take place at many levels of processing. Imaging studies, in particular, have revealed the greater activation of auditory areas and areas outside of sensory processing areas when attending to a stimulus. We present here a brief review of the consequences of such non-passive listening and go on to describe some of the experiments we are conducting to investigate them. In imaging studies, using fMRI, we can demonstrate the activation of attention networks that are non-specific to the sensory modality as well as greater and different activation of the areas of the supra-temporal plane that includes primary and secondary auditory areas. The profuse descending connections of the auditory system seem likely to be part of the mechanisms subserving attention to sound. These are generally thought to be largely inactivated by anaesthesia. However, we have been able to demonstrate that even in an anaesthetised preparation, removing the descending control from the cortex leads to quite profound changes in the temporal patterns of activation by sounds in thalamus and inferior colliculus. Some of these effects seem to be specific to the ear of stimulation and affect interaural processing. To bridge these observations we are developing an awake behaving preparation involving freely moving animals in which it will be possible to investigate the effects of consciousness (by contrasting awake and anaesthetized), passive and active listening
Issues and Observations on Applications of the Constrained-Path Monte Carlo Method to Many-Fermion Systems
We report several important observations that underscore the distinctions
between the constrained-path Monte Carlo method and the continuum and lattice
versions of the fixed-node method. The main distinctions stem from the
differences in the state space in which the random walk occurs and in the
manner in which the random walkers are constrained. One consequence is that in
the constrained-path method the so-called mixed estimator for the energy is not
an upper bound to the exact energy, as previously claimed. Several ways of
producing an energy upper bound are given, and relevant methodological aspects
are illustrated with simple examples.Comment: 28 pages, REVTEX, 5 ps figure
Functional maturation of isolated neural progenitor cells from the adult rat hippocampus
Although neural progenitor cells (NPCs) may provide a source of new neurons to alleviate neural trauma, little is known about their electrical properties as they differentiate. We have previously shown that single NPCs from the adult rat hippocampus can be cloned in the presence of heparan sulphate chains purified from the hippocampus, and that these cells can be pushed into a proliferative phenotype with the mitogen FGF2 [Chipperfield, H., Bedi, K.S., Cool, S.M. & Nurcombe, V. (2002) Int. J. Dev. Biol., 46, 661-670]. In this study, the active and passive electrical properties of both undifferentiated and differentiated adult hippocampal NPCs, from 0 to 12 days in vitro as single-cell preparations, were investigated. Sparsely plated, undifferentiated NPCs had a resting membrane potential of approximate to -90 mV and were electrically inexcitable. In > 70%, ATP and benzoylbenzoyl-ATP evoked an inward current and membrane depolarization, whereas acetylcholine, noradrenaline, glutamate and GABA had no detectable effect. In Fura-2-loaded undifferentiated NPCs, ATP and benzoylbenzoyl-ATP evoked a transient increase in the intracellular free Ca2+ concentration, which was dependent on extracellular Ca2+ and was inhibited reversibly by pyridoxalphosphate-6-azophenyl-2'-4'-disulphonic acid (PPADS), a P2 receptor antagonist. After differentiation, NPC-derived neurons became electrically excitable, expressing voltage-dependent TTX-sensitive Na+ channels, low- and high-voltage-activated Ca2+ channels and delayed-rectifier K+ channels. Differentiated cells also possessed functional glutamate, GABA, glycine and purinergic (P2X) receptors. Appearance of voltage-dependent and ligand-gated ion channels appears to be an important early step in the differentiation of NPCs
Structural studies of metal ligand complexes by ion mobility-mass spectrometry
Collision cross sections (CCS) have been measured for three salen ligands, and their complexes with copper and zinc using travelling-wave ion mobility-mass spectrometry (TWIMS) and drift tube ion mobility-mass spectrometry (DTIMS), allowing a comparative size evaluation of the ligands and complexes. CCS measurements using TWIMS were determined using peptide and TAAH calibration standards. TWIMS measurements gave significantly larger CCS than DTIMS in helium, by 9 % for TAAH standards and 3 % for peptide standards, indicating that the choice of calibration standards is important in ensuring the accuracy of TWIMS-derived CCS measurements. Repeatability data for TWIMS was obtained for inter- and intra-day studies with mean RSDs of 1. 1 % and 0. 7 %, respectively. The CCS data obtained from IM-MS measurements are compared to CCS values obtained via the projection approximation, the exact hard spheres method and the trajectory method from X-ray coordinates and modelled structures using density functional theory (DFT) based methods. © 2013 Springer-Verlag Berlin Heidelberg
Seasonal migration of Cnaphalocrocis medinalis (Lepidoptera: Crambidae) over the Bohai Sea in northern China
The rice leaf roller, Cnaphalocrocis medinalis (Guenée), is a serious insect pest of rice with a strong migratory ability. Previous studies on the migration of C. medinalis were mostly carried out in tropical or subtropical regions, however, and what the pattern of seasonal movements this species exhibits in temperate regions (i.e. Northern China, where they cannot overwinter) remains unknown. Here we present data from an 11-year study of this species made by searchlight trapping on Beihuang Island (BH, 38°24′N; 120°55′E) in the centre of the Bohai Strait, which provides direct evidence that C. medinalis regularly migrates across this sea into northeastern agricultural region of China, and to take advantage of the abundant food resources there during the summer season. There was considerable seasonal variation in number of C. medinalis trapped on BH, and the migration period during 2003–2013 ranged from 72 to 122 days. Some females trapped in June and July showed a relatively higher proportion of mated and a degree of ovarian development suggesting that the migration of this species is not completely bound by the ‘oogenesis-flight syndrome’. These findings revealed a new route for C. medinalis movements to and from Northeastern China, which will help us develop more effective management strategies against this pest
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