An aid to the development of Botswana's resources: Section on hydrology

The author has identified the following significant results. It is proved that FCC's can be used for a simple estimate of the total evaportranspiring area of the Okavango Delta, sufficiently accurate for preliminary inputs for the development of mathematical model of the surface hydrology of the delta. The color coded matrix has shown as interesting inverse correlation with an array on the same grid prepared by ecologists from air photography study, for percent liable to flood

An aid to the development of Botswana's resources

There are no author-identified significant results in this report

Stanford Aerospace Research Laboratory research overview

Over the last ten years, the Stanford Aerospace Robotics Laboratory (ARL) has developed a hardware facility in which a number of space robotics issues have been, and continue to be, addressed. This paper reviews two of the current ARL research areas: navigation and control of free flying space robots, and modelling and control of extremely flexible space structures. The ARL has designed and built several semi-autonomous free-flying robots that perform numerous tasks in a zero-gravity, drag-free, two-dimensional environment. It is envisioned that future generations of these robots will be part of a human-robot team, in which the robots will operate under the task-level commands of astronauts. To make this possible, the ARL has developed a graphical user interface (GUI) with an intuitive object-level motion-direction capability. Using this interface, the ARL has demonstrated autonomous navigation, intercept and capture of moving and spinning objects, object transport, multiple-robot cooperative manipulation, and simple assemblies from both free-flying and fixed bases. The ARL has also built a number of experimental test beds on which the modelling and control of flexible manipulators has been studied. Early ARL experiments in this arena demonstrated for the first time the capability to control the end-point position of both single-link and multi-link flexible manipulators using end-point sensing. Building on these accomplishments, the ARL has been able to control payloads with unknown dynamics at the end of a flexible manipulator, and to achieve high-performance control of a multi-link flexible manipulator

The effect of flight line spacing on radioactivity inventory and spatial feature characteristics of airborne gamma-ray spectrometry data

Airborne Gamma Spectrometry (AGS) is well suited to the mapping of radioactivity in the environment. Flight parameters (e.g. speed and line spacing) directly affect the rate of area coverage, cost, and data quality of any survey. The influences of line spacing have been investigated for data from inter‐tidal, coastal and upland environments with a range of <sup>137</sup>Cs activity concentrations and depositional histories. Estimates of the integrated <sup>137</sup>Cs activity (‘inventory’) within specified areas and the shapes of depositional features were calculated for subsets of the data at different line spacings. Features with dimensions greater than the line spacing show variations in inventory and area of less than 3%, and features with dimensions less than the line spacing show larger variations and a decreased probability of detection. The choice of line spacing for a task is dependent on the dimensions of the features of interest and required edge definition. Options for line spacing for different tasks are suggested. It is noted that for regional mapping, even 5–10 km line spacing can produce useful data

First report of Metarhizium anisopliae IP 46 pathogenicity in adult Anopheles gambiae s.s. and An. arabiensis (Diptera; Culicidae).

The entomopathogenic fungus Metarhizium anisopliae isolate IP 46, originating from a soil sample collected in 2001 in the Cerrado of Central Brazil, was tested for its ability to reduce the survival of adult male and female Anopheles gambiae s.s. and An. arabiensis mosquitoes. A 6-h exposure to the fungus coated on test paper at a concentration of 3.3 x 106 conidia cm-2 reduced the daily survival of both mosquito species (HR = 3.14, p < 0.001), with higher risk of dying in An. gambiae s.s relative to An. arabiensis (HR = 1.38, p < 0.001). Fungal sporulation was observed in >95% of mosquito cadavers in the treatment groups. The results indicate that M. anisopliae IP 46 has the potential to be a bio-control agent for African malaria vector species, and is a suitable candidate for further research and development

Methodological Issues in Experimental IS Research: Experiences and Recommendations

Within the last ten years, the use of experimental methodology in information systems research has substantially increased. However, despite the popularity of experimentation, studies suffer from major methodological problems: (1) lack of underlying theory, (2) proliferation of measuring instruments, (3) inappropriate research designs, (4) diversity of experimental tasks, and (5) lack of internal validity. These problems have led to an accumulation of conflicting results in several areas of IS research, in particular, research in the area of graphics and information presentation. This paper uses the area of information presentation format to explore the nature of the methodological problems mentioned above and to suggest potential remedies: 1. Due to the lackoftheoretical basis, informationpresentationresearchers do nothave any common ground for conducting and interpreting their results. This has resulted in oneshot, ad-hoc studies that do not build on the work of others. No state of relatedness among studies has emerged. Only through progrums of research can we hope for an underlying theory to emerge. 2. The proliferation of measuring instruments, many of which may have problems with reliability and validity, has plagued IS research. Again, only through a program of research can we hope to construct a set ofmeasuring instruments applicable and easily adaptable to a large number of studies 3. With regard to research design, simplistic and nonpragmatic studies as well as poorly controlled experiments have impeded the progress of IS research. Suggested remedies include the adoption of multivariate designs, use of decision maker productivity as a dependent vatiable, and more effective experimental control through measurement of factors that are 1mown from previous research to influence decision performance. 4. The presence of a multitude of task environments has also posed problems. The employment of diverse tasks makes comparisons of results across studies inappropriate. A taxomony of tasks must be developed before we can meaningfully integrate research findings. 5. Many studies have suffered from internal validity problems. A remedy for this requires more effective precautions to ensure that the findings of a study are due to the factors researched rather than to accidents. Tb illustrate this last problem of internal validity and the steps needed to improve the experimental studies involving mangerial graphics is described. The research study conducted at the University of Minnesota was initially set up to investigate the relationship between graphical decision aids, task complexity, and decision maker performance. First, a task, and a case that was to provide a task setting, were developed. Also, questionnaires and tests were constructed to gather information on the (1) backgroundof subjects, (2) motivation of subjects, (3) subjects\u27 satisfaction withthe graphs, (4) perceived complexity and difficulty of the problem solving task, and (5) the subjects\u27 interpretation accuracy in reading graphs After the development of the tasl and other experimental material, the experiment was pretested The results from the pilot study gave the authors every reason to believe that the task did not have any major validity problems. However, whenthe experiment was actually given to 63 graduate students, the data didnotreveal any consistent patterns due to graphical and task treatments. This, of course, concerned the authors, and, as a result, attention was directed toward improving the experimental task, research design, and measurement A second experiment was conducted to test whether the insignificant results in the first experimentwere causedbythegraphsorbymisleadingorconfusinginformationinthetask. The data from the second experiment collected on 20 experimental subjects, convinced the authorsthatthemainproblemcausingtheinsignificantresultshadnotbeenthepoorquality of the graphs, but the fact that, in general subjects were just not able to perform the task However, the authors did not know whether this poor performance was due to an overly difficult task or to misleading or confusing information within the task. Therefore, a third experiment was conducted to resolve this question. The third study used 17 managers as experimental subjects. It was assumed that if the managers couldsatisfactorilycompletethetasktheauthors couldconcludethatthe taskwas valid, but too difficult for graduate students. The analysis of the data collected from the third experiment confirmed, however, that serious problems existed with the task itself. Debriefings of the managers indicated that the case description, in combination with the presented data on marketing variables, included confusing and misleading data Obviously, thetaskwasnotprovidingthebasisforansweringtheresearchquestionontherelationshipof task, presentation format, the decision performance. Thus, a majorrevision of the task was undertaken. The revised material is currently undergoing pretesting. In summary, the authors have gone through several experiments in searching and testing for valid measurements. During this process we have learned an invaluable lesson that we hope willbe usefulto othersintheirresearch endeavors. We discoveredthatthe process of coming up with an effective taskand variable measurementis lengthy, costly, and mayhave uncertain outcomes even if considerable precautions are taken. For experimental IS researchers particularly those performing studies on the use of managerial graphics, cautions and guidelines are provided to help them address more effectively the common methodological

Time-Lapse Imaging in Polar Environments

Although the drivers of climate change and its consequences in polar regions are becoming better understood [Holland and Bitz, 2003] and well monitored [Serreze et al., 2002; Doran et al., 2002b], measuring the responses of polar landscapes to changing climate boundary conditions is challenging: Polar landscapes typically respond slowly to warming but abruptly to melting [Gooseff et al., 2011]

Amazonian‐aged fluvial valley systems in a climatic microenvironment on Mars: Melting of ice deposits on the interior of Lyot Crater

Valley networks, regional drainage patterns suggesting liquid water stability at the surface, are confined to early in the history of Mars (the Noachian/Hesperian boundary and before), prior to a major climate transition to the hyperarid cold conditions of the Amazonian. Several later fluvial valley systems have been documented in specific Hesperian and Early Amazonian environments, and are thought to have formed due to local conditions. Here we describe fluvial valley systems within Lyot crater that have the youngest well-constrained age reported to date (Middle or Late Amazonian) for systems of this size (tens of km). These valleys are linked to melting of near-surface ice-rich units, extend up to ∼50 km in length, follow topographic gradients, and deposit fans. The interior of Lyot crater is an optimal micro-environment, since its low elevation leads to high surface pressure, and temperature conditions at its location in the northern mid-latitudes are sufficient for melting during periods of high-obliquity. This micro-environment in Lyot apparently allowed melting of surface ice and the formation of the youngest fluvial valley systems of this scale yet observed on Mars

A new species of stalked crinoid (Echinodermata) of possible Late Silurian age from central Newfoundland

A new fossil locality within a sequence previously assigned to the Middle Ordovician Baie D'Espoir Group in south-central Newfoundland contains fragmented crinoid columnals and brachiopods. Distinctive, pentastellate crinoid columnals, similar to those assigned to the monobathrid camerate Hexacrinites Austin and Austin by Russian authors, are named Hexacrinites? Pentastellatus n. sp. Nodal(?) columnals of this species have a circular, depressed articular facet, with a conical to bowl-like crenularium, a depressed, circular areola, a raised perilumen and a short, slender axial canal of pentagonal section. The oldest Hexacrinites sensu stricto are Late Silurian, suggesting that the fossiliferous strata have been incorrectly assigned to the Ordovician. Cross-sections of brachiopods from the same locality include an example that resembles several Early Silurian to Late Devonian pentameroid genera including Brooksina Kirk, 1922. Correlation with Late Silurian, bivalve-bearing strata SO km to the northeast would indicate that a major unconformity may occur above the fossiliferous Early and Middle Ordovician strata and the Early Ordovician ophiolite complexes. R&#xC9;SUM&#xC9; Un nouvel emplacement de fossiles &#xE0; I'int&#xE9;rieur d'une sequence auparavant attribute au groupe de l'Ordovicien moyen de Baie d'Espoir dans le centre-sud de Terre-Neuve renferme des fragments de columnales et de brachiopodes de crinoldes. Des columnales de crinoldes penta&#xE9;toil&#xE9;es caract&#xE9;ristiqucs, semblables &#xE0; celles attribut&#xE9;es &#xE0; l’Hexacrinites Austin and Austin &#xE0; loges monobathrides par des auteurs russes, sont baptis&#xE9;es nouvelle esp&#xE8;ce pentastellatus d'Hexacrinites?. Les columnales nodales(?) de cette esp&#xE8;ce sont pourvues d'une facette articulaire renfonc&#xE9;e et circulaire munie d'un crenularium allant de conique &#xE0; bomb&#xE9;, d'une ar&#xE9;ole circulaire renfoncie, d'un p&#xE9;rilumen sur&#xE9;lev&#xE9; et d'un canal axial mince et court de section pentagonalc. Les plus anciens Hexacrinites, au sens strict, remontent au Silurien sup&#xE9;rieur, ce qui permet de supposer qu'on a incorrectement attribu&#xE9; la strate fossilif&#xE8;re &#xE0; l'Ordovicien. Des i&#xE9;chantillons repr&#xE9;sentatifs de brachiopodes du m&#xEA;me emplacement comprennent un exemple qui ressemble &#xE0; plusieurs genres de pentam&#xE9;roides datant du Silurien inf&#xE9;rieur au D&#xE9;vonien sup&#xE9;rieur, notamment le Brooksina Kirk, 1922. Leur corr&#xE9;lation avec des strates renfermant des bivalves du Silurien sup&#xE9;rieur &#xE0; 50 km au nord-cst signale qu'une discordance importantc pourrait se pr&#xE9;senter au-dessus des strates fossiliferes de l'Ordovicien inf&#xE9;rieur ou moyen de m&#xEA;me que des complexes d'ophiolites de l'Ordovicien inf&#xE9;rieur. [Traduit par la r&#xE9;daction

MUBs inequivalence and affine planes

There are fairly large families of unitarily inequivalent complete sets of N+1 mutually unbiased bases (MUBs) in C^N for various prime powers N. The number of such sets is not bounded above by any polynomial as a function of N. While it is standard that there is a superficial similarity between complete sets of MUBs and finite affine planes, there is an intimate relationship between these large families and affine planes. This note briefly summarizes "old" results that do not appear to be well-known concerning known families of complete sets of MUBs and their associated planes.Comment: This is the version of this paper appearing in J. Mathematical Physics 53, 032204 (2012) except for format changes due to the journal's style policie