A human factors approach to range scheduling for satellite control

Range scheduling for satellite control presents a classical problem: supervisory control of a large-scale dynamic system, with unwieldy amounts of interrelated data used as inputs to the decision process. Increased automation of the task, with the appropriate human-computer interface, is highly desirable. The development and user evaluation of a semi-automated network range scheduling system is described. The system incorporates a synergistic human-computer interface consisting of a large screen color display, voice input/output, a 'sonic pen' pointing device, a touchscreen color CRT, and a standard keyboard. From a human factors standpoint, this development represents the first major improvement in almost 30 years to the satellite control network scheduling task

Permian palynomorphs from the number 5 seam, Ecca Group, Witbank/Highveld coalfields, South Africa

A palynological study of the number 5 seam in the Ecca group has yielded a wide variety of miospores, with a lateral and vertical consistency in their relative abundance, diversity and composition. Striate bisaccate pollen genera predominate, particularly Protohaploxypinus Samoilovich emend. Morbey 1975, Striatopodocarpites Zoricheva & Sedova ex Sedova emend. Hart 1964 and Weylandites Bharadwaj & Srivastava 1969. On a regional scale the number 5 seam palynomorphs correlate both quantitatively and qualitatively with Biozone F of MacRae (1988) from the Waterberg and Pafuri coal-bearing basins, and Hammanskraal plant locality. Broad palaeoenvironmental inferences drawn from both the palynology and sedimentology of this seam, support a flood plain setting, comprising shallow wide open pans and peat swamps interspersed with wide water-logged mud flats . The surrounding highlands would have been forested mostly by plants adapted to wind dispersal with colonisation of the levees and margins of smaIl ponds by spore producers. The age of the number 5 seam is tentatively suggested as Guadalupian, which in turn is equated with the Tatarian (European Standard usage); Midian to Dzhulfian (Tethys usage).University of the Witwatersrand; Bernard Price Institute for Palaeontological Researc

Simple Reaction Time of Ipsilateral and Contralateral Hand to Monaurally Presented Tones of Different Pitch with Binaural White Noise

This study hypothesized that reaction times to monaural auditory stimuli are shorter with the ipsilateral hand than with the contralateral hand under binaural white noise stimulation, and that ipsi- and contralateral reactions do not differ in the absence of white noise. The relationship between the ipsilateral-contralateral reaction time difference and the frequency of the reaction signal was also determined. In experiment I, 10 male undergraduate students each performed 20 ipsilateral and 20 contralateral reactions to each of 6 signal frequencies (400, 800,1200,1600, 2000, 2400 cps) under binaural white noise stimulation. In experiment II, 10 male undergraduate students each performed 20 ipsi- and 20 contralateral reactions, at one stimulus frequency, under white noise on and white noise off conditions. The results support both hypotheses ( p \u3c .001), and also indicate that signal frequency has a significant effect on contralateral reactions· ( p \u3c .001) but not on ipsilateral reactions. Close agreement was obtained with results of other callosal transmission studies, and support provided for the theory that the ear asymmetry effect is caused in part by the occlusion of ipsilateral auditory connections by contralateral ones. The results also suggest that the effect of signal frequency on contralateral reactions is related to the mechanism limiting the frequency at which binaural beats are perceived

Relative Rates of Return to Controlled Irrigation Among Classes of Summer Paddy in the Guayas Basin, Ecuador

The primary objective of this study was to examine rice production methods with special emphasis on farm and water irrigation management practices in the different rice farm types of the Guayas Basin of Ecuador. To do this, farmers were divided into eight categories on the basis of farm practices, seasonal farming, irrigation facilities and level of mechanization. Profits per hectare ranged from 4,807 to 762.10 sucres per hectare. Mechanization varied from totally mechanized to total absence of machinery. Year round farming varied to seasonal farming. Average production varied from 110 quintals of hulled rice to 20 quintals per hectare. The preparation of farm budgets for the different types, presented some problems, due to the lack of available records by the small farmers and reluctance to provide data by the large mechanized units. The cost/benefit ratios of changing from one type of farming to another were calculated as well as the labor absorption possibilities for the different types of farming. These could provide a criteria for planification of rice policies in Ecuador

Using an ontology for interoperability and browsing of museum, library and archive information

Ontologies play an important part in the development of the future ‘semantic web’; the CIDOC conceptual reference model (CRM) is an ontology aimed at the cultural heritage domain. This paper describes a Concept Browser, developed for the EU/IST-funded SCULPTEUR project (semantic and content-based multimedia exploitation for European benefit environment (programme IST-2001-no. 35372); May 2002 to May 2005), which is able to access different museum information systems through a common ontology, the CRM. The development of this Concept Browser has required mappings from the legacy museum database systems to the CRM. The crucial process of creating the mappings is described, using the C2RMF catalogue (EROS) and library databases as a case study

Evaluation of enzyme immunoassays in the diagnosis of camel (Camelus dromedarius) trypanosomiasis:a preliminary investigation

Three enzyme immunoassays were used for the serodiagnosis of Trypanosoma evansi in camels in the Sudan in order to evaluate their ability to discriminate between infected and non-infected animals. Two assays were used for the detection of trypanosomal antibodies, one using specific anti-camel IgG conjugate and another using a non-specific Protein A conjugate. The third assay detected the presence of trypanosomal antigens using anti-T. evansi antibodies in a double antibody sandwich assay. Inspection of the frequency distribution of assay results suggested that the ELISA for circulating trypanosomal antibodies using specific antisera and the ELISA for circulating antigens can distinguish between non-infected camels and infected camels exhibiting patent infections or not. The ELISA using Protein A conjugate to bind non-specifically to camel immunoglobulin did not appear to discriminate between infected and non-infected animals

Contributions in the field of palaeopalynology at the Bernard Price Institute, past, present and future

Main articleA brief chronological summary of the palynological research carried out by students and past members of the staff at the Bernard Price Institute for Palaeontological Research is presented. The contribution that each of these studies has made to the understanding of stratigraphic relationships in the southern African region is highlighted. A correlation chart of palynological biozones documented from South African localities is presented (Table 1).Non

Nucleation, solvation and boiling of helium excimer clusters

Helium excimers generated by a corona discharge were investigated in the gas and normal liquid phases of helium as a function of temperature and pressure between 3.8 and 5.0 K and 0.2 and 5.6 bar. Intense fluorescence in the visible region showed the rotationally resolved $d^3\Sigma_u^+ \rightarrow b^3\Pi_g$ transition of He$_2^*$. With increasing pressure, the rotational lines merged into single features. The observed pressure dependence of linewidths, shapes and lineshifts established phases of coexistence and separation of excimer-helium mixtures, providing detailed insight into nucleation, solvation and boiling of He$_2^*$-He$_n$ clusters.Comment: 5 pages, 5 figure