Classification of imaging spectrometers for remote sensing applications

The continuing development of new and fundamentally different classes of imaging spectrometers has increased the complexity of the field of imaging spectrometry. The rapid pace at which new terminology is introduced to describe the new types of imaging spectrometers sometimes leads to confusion, particularly in discussions of the relative merits of the different types. In some cases, multiple different terms are commonly used to describe the same fundamental approach, and it is not always clear when these terms are synonymous. Other terminology in common use is overly broad. When a single term may encompass instruments that operate in fundamentally different ways, important distinctions may be obscured. In the interest of clarifying the terminology used in imaging spectrometry, we present a comprehensive system for classification of imaging spectrometers based on two fundamental properties: the method by which they scan the object spatially, and the method by which they obtain spectral information

Limiting aspect ratios of Sagnac interferometers

Any two-beam interferometer may be employed as a Fourier transform spectrometer. The two most commonly used for Fourier transform spectrometry are the Michelson interferometer and the Sagnac interferometer, the relative merits of which have been discussed in the literature. Typically, it is the interferometer that limits the acceptable range of angles for the input beam, and this maximum acceptance angle in turn limits the etendue, and hence limits the responsivity of the instrument when viewing an extended source. In designs where the interferometer is in a diverging or converging beam, the allowable range of input angles limits the focal ratio of the instrument, while in designs where the beam is collimated through the interferometer, this effect limits the field-of-view of the instrument. In a Michelson, it is a loss of fringe contrast that limits the range of acceptance angles; a limitation that is discussed in many general texts on optics. A Sagnac, however, suffers no such loss of contrast as the range of acceptance angles is increased. The maximum acceptance angle for a Sagnac is instead limited by vignetting, caused by the geometry of the interferometer. The limitation for a Sagnac has an origin and behavior entirely different from that found for a Michelson, and has not been previously discussed in the literature. It is therefore important to understand this limitation when designing a Sagnac interferometer for Fourier transform spectrometry. This vignetting limitation may be quantified by an aspect ratio, which we define as the ratio of the separation of the entrance and exit apertures to the width of these apertures in the plane of the interferometer. To facilitate the design of Sagnac interferometers for Fourier transform spectrometry, we discuss the limitations on the aspect ratio and derive equations for the limiting aspect ratios for nine variations of the Sagnac interferometer

IMPACT OF A MORE INTENSIVE INSECT PEST INFESTATION LEVEL ON COTTON PRODUCTION: TEXAS HIGH PLAINS

This study evaluated implications of increased bollworm problems in a 20-county area of the Texas High Plains relative to cotton yields and economic impact. Results did not indicate a serious effect of bollworms upon lint yield when insecticides were used for control. However, estimated annual reduction in farmer profit due to the bollworm for 1979-81 was over $30 million. Yields were estimated to decline about 300,000 bales without insecticide use and about 30,000 bales with insecticide use. This decline suggests potentially serious implications for the comparative economic position of cotton in this region if insecticide resistance were to develop among insect pests.Crop Production/Industries,

The Multispectral Microscopic Imager: Integrating Microimaging with Spectroscopy for the In-Situ Exploration of the Moon

To maximize the scientific return, future robotic and human missions to the Moon will need to have in-situ capabilities to enable the selection of the highest value samples for returning to Earth, or a lunar base for analysis. In order to accomplish this task efficiently, samples will need to be characterized using a suite of robotic instruments that can provide crucial information about elemental composition, mineralogy, volatiles and ices. Such spatially-correlated data sets, which place mineralogy into a microtextural context, are considered crucial for correct petrogenetic interpretations. . Combining microscopic imaging with visible= nearinfrared reflectance spectroscopy, provides a powerful in-situ approach for obtaining mineralogy within a microtextural context. The approach is non-destructive and requires minimal mechanical sample preparation. This approach provides data sets that are comparable to what geologists routinely acquire in the field, using a hand lens and in the lab using thin section petrography, and provide essential information for interpreting the primary formational processes in rocks and soils as well as the effects of secondary (diagenetic) alteration processes. Such observations lay a foundation for inferring geologic histories and provide "ground truth" for similar instruments on orbiting satellites; they support astronaut EVA activities and provide basic information about the physical properties of soils required for assessing associated health risks, and are basic tools in the exploration for in-situ resources to support human exploration of the Moon

Immunophenotypic analysis of cell cycle status in acute myeloid leukaemia: relationship to cytogenetics, genotype and clinical outcome

Cell cycle status may play an important role in directing patient therapy. We therefore determined the cell cycle status of leukaemic cells by immunophenotypic analysis of bone marrow trephine biopsies from 181 patients with acute myeloid leukaemia (AML) and correlated the results with biological features and clinical outcome. There was considerable heterogeneity between patients. The presenting white cell count significantly correlated with the proportion of non-quiescent cells (P < 0·0001), of cycling cells beyond G1 (P < 0·0001) and the speed of cycling (P < 0·0001). Profiles in acute promyelocytic leukaemia (APL) differed from non-APL and were consistent with more differentiated cells with reduced proliferative potential, but no significant differences were observed between non-APL cytogenetic risk groups. NPM1 mutations but not FLT3 internal tandem duplication (FLT3ITD ) were significantly associated with a higher proportion of cells beyond G1 (P = 0·002) and faster speed of cycling (P = 0·003). Resistance to standard cytosine arabinoside and daunorubicin induction chemotherapy was significantly related to a slower speed of cycling (P = 0·0002), as was a higher relapse rate (P = 0·05), but not with the proportion of non-quiescent cells or actively cycling cells. These results show a link between the cycling speed of AML cells and the response to chemotherapy, and help to identify a group with a very poor prognosis

Imaging Fourier transform spectrometers for environmental sensing

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77073/1/AIAA-1998-291-523.pd

Australian Education Joins the OECD : Federalism, Regionalization, and the Role of Education in a Time of Transition

This chapter argues that Australian interactions with the Organisation for Economic Co-operation and Development (OECD) in the field of education in the mid- to late-1970s pointed in two separate but not yet incompatible directions—one equity-oriented and the other more in line with the standardization and accountability regime typically identified with the OECD’s current policies—both of which favored a shift of authority toward the national level in educational policy-making. In the process, the chapter highlights the importance of considering movements between different spatial levels of analysis when tracing the ability of international organizations to get their ideas and visions “out of house.” The chapter first outlines the international and domestic contexts for Australia’s early involvement in the OECD, followed by a discussion of the negotiations of state and federal interests on the Australian Commonwealth Department of Education’s advisory committee on OECD matters. This discussion, in turn, frames the last three analytical sections of the chapter, on interactions between the OECD and the Australian education authorities at different levels on initiatives negotiating both the location of authority between these levels and the role of education at a time when the relation between its social and economic potential was up for revision.Non peer reviewe

PISA: a political project and a research agenda

PISA (Programme for International Student Assessment) is one of two large scale international comparative projects of student assessment that now exert considerable influence upon school science education policy, the other being TIMSS (Trends in International Mathematics and Science Study). This paper focuses on PISA, now the most influential study. This article outlines the origins of PISA, identifies some of the challenges in its construction and the claims made for it. It argues that while the statistical and methodological aspects of PISA have received much research attention, other elements of PISA have been largely ignored. In particular, there are several outcomes of PISA testing that point towards a significant research agenda. In addition, the political, ideological and economic assumptions underpinning the PISA project have implications for school science curriculum policy that deserve closer scrutiny and debate

Lunar Flashlight: Illuminating the Moon's South Pole

Recent reflectance data from LRO instruments suggest water ice and other volatiles may be present on the surface in lunar permanently shadowed regions, though the detection is not yet definitive. Understanding the composition, quantity, distribution, and form of water and other volatiles associated with lunar permanently shadowed regions (PSRs) is identified as a NASA Strategic Knowledge Gap (SKG) for Human Exploration. These polar volatile deposits are also scientifically interesting, having the potential to reveal important information about the delivery of water to the Earth-Moon system