878 research outputs found
Increased demand for rapid access to UK magnetic observatory data : implications for quality control procedures
During the last decade the demand for magnetic observatory data has steadily increased both from the scientific community and in particular from commercial organisations. Not only are the quantity of data products greater now but the speed at which they are delivered is faster and the
quality of the data provided better.
The modern user requirements for timely data have prompted
the need for improved automatic procedures utilising the new
technologies available. This has to be balanced against the user requirements for accuracy, which necessitate rigorous quality control procedures. While some of these have been automated, as is shown in the flow diagram, there remains a requirement for human interpretation and action if and when the data contain errors. Software development to reduce this human intervention is on-going
Ap in real time : IUGG- Sapporo, Japan, July 2003 : session GAV.02
The 3-hourly planetary indices Kp and ap and the daily planetary index, Ap, which are derived by GeoForschungsZentrum (GFZ), Potsdam, on behalf of the International Service of Geomagnetic Indices (ISGI), are made available twice per month. This time delay is inevitable because of the need for a high quality homogenous data set. However, the process may not be sufficiently responsive to the needs of the space weather community, in particular forecasters, where small discrepancies in the data are usually less important than their timely availability. An automated algorithm has been developed by the British Geological Survey (BGS) to derive real-time estimates of the ap and Ap indices, called apest and Ap respectively. These are available on-line at www.bgs.ac.uk/gifs/apindex.html. The derivation process of these est indices is described, which has been designed to match that of the definitive indices as closely as possible. A comparison between the BGS values of ap , Ap and the corresponding definitive values is presented. Modifications to the derivation est est process are still on-going, taking advantage of the advances made by the INTERMAGNET programme in data delivery. The ultimate goal is for GFZ to take over the responsibility for derivation and delivery of the real time indices, which could be considered quick-look or provisional values
New K-Indices from South Atlantic Observatories : Port Stanley and Ascension Island
Port Stanley and Ascension Island magnetic observatories have been in continuous operation since the early 1990's. These remote South Atlantic locations provide much needed coverage in the global network of geomagnetic observatories and help to monitor the South Atlantic Anomaly. To enhance the production of longitude-sector planetary magnetic activity indices there is a requirement for local 3-hourly K-index values from Port Stanley (PST) observatory. We describe the process followed to establish an automated routine for the derivation of the indices and we assess the congruence of the indices to those available from other suitably located observatories. A similar procedure has been followed for Ascension Island observatory although this is not shown here
Modelling the effects of space weather at the Earth’s surface : a UK geoelectric field model
Geomagnetically Induced Currents (GIC), which can flow in technological systems such as power transmission grids, are a consequence of the geoelectric field induced at the surface of the Earth during geomagnetic storms. This poster describes the development of a new 3D 'Thin-Sheet' geoelectric field model which covers the whole of the UK and includes the influence of the surrounding shelf seas. The model can be used to compute the response of the geoelectric field to geomagnetic storms. In conjunction
with a power grid model this enables us to estimate GIC flow in power networks. As an example, we consider the major geomagnetic storm of October 2003. It is envisaged that the model will form one component of a near
real time GIC warning package which is currently being developed by the British Geological Survey (BGS) in conjunction with Scottish Power Plc. The magnetic field associated with the induced geoelectric field is easily calculated. Thus, the electric field model may also be of interest to those studying the effect of internal (induced) geomagnetic field signals on the total measured geomagnetic field
Plant Individuality and Multilevel Selection Theory
This chapter develops the idea that the germ-soma split and the suppression of individual fitness differences within the corporate entity are not always essential steps in the evolution of corporate individuals. It illustrates some consequences for multilevel selection theory. It presents evidence that genetic heterogeneity may not always be a barrier to successful functioning as a higher-level individual. This chapter shows that levels-of-selection theorists are wrong to assume that the central problem in transitions is always that of minimizing within-group competition. Evidence of intralevel conflict does not qualify as evidence against the existence of a higher level of selection
Plant individuality: a solution to the demographer’s dilemma
The problem of plant individuality is something which has vexed botanists throughout the ages, with fashion swinging back and forth from treating plants as communities of individuals (Darwin 1800; Braun and Stone 1853; Münch 1938) to treating them as organisms in their own right, and although the latter view has dominated mainstream thought most recently (Harper 1977; Cook 1985; Ariew and Lewontin 2004), a lively debate conducted mostly in Scandinavian journals proves that the issues are far from being resolved (Tuomi and Vuorisalo 1989b; Fagerström 1992; Pan and Price 2001). In this paper I settle the matter once and for all, by showing which elements of each side are correct
Using Laser Tweezers For Manipulating Isolated Neurons In Vitro
In this paper and video, we describe the protocols used in our laboratory to study the targeting preferences of regenerating cell processes of adult retinal neurons in vitro. Procedures for preparing retinal cell cultures start with the dissection, digestion and trituration of the retina, and end with the plating of isolated retinal cells on dishes made especially for use with laser tweezers. These dishes are divided into a cell adhesive half and a cell repellant half. The cell adhesive side is coated with a layer of Sal-1 antibodies, which provide a substrate upon which our cells grow. Other adhesive substrates could be used for other cell types. The cell repellant side is coated with a thin layer of poly-HEMA. The cells plated on the poly-HEMA side of the dish are trapped with the laser tweezers, transported and then placed adjacent to a cell on the Sal-1 side to create a pair. Formation of cell groups of any size should be possible with this technique. "Laser-tweezers-controlled micromanipulation" means that the investigator can choose which cells to move, and the desired distance between the cells can be standardized. Because the laser beam goes through transparent surfaces of the culture dish, cell selection and placement are done in an enclosed, sterile environment. Cells can be monitored by video time-lapse and used with any cell biological technique required. This technique may help investigations of cell-cell interactions
Interest factor in junior high school English teaching
This item was digitized by the Internet Archive. Thesis (M.A.)--Boston Universityhttps://archive.org/details/interestfactorin00cla
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