Aid In Interpretation Research Articles

Tensor VLF measurements: Our first experiences

VLF and magnetic maps over crystalline areas constitute major tools for delineating lateral changes in electrical conductivity and magnetisation, respectively, in the upper few hundred meters of the Earth’s crust. Aeromagnetic data in particular have been utilised on a variety of scales for basement mapping, crustal geology mapping, tectonic mapping, mineral resource exploration, geothermal exploration and many other applications. VLF data have been used in particular to delineate zones of low resistivity in the upper few hundred meters of the crystalline crust. Such zones are often related to fluid filled fracture zones or to sedimentary infill in valleys, which in turn may be underlain by fractured zones. Mineralised zones and black schists are also excellent targets because of their low resistivity, but in general they are less frequent than fluid filled fractured zones and valleys.Tensor VLF measurements using several VLF transmitters simultaneously defines at each measuring site a unique tipper vector. From that a number of rotational invariants are derived, one of which, the so-called peaker, defined as the horizontal divergence of the tipper vector, is particularly useful as an interpretational aid. A simple model is developed to understand the interrelationship between VLF and magnetic anomaly maps. If common sources exist the model predicts that the peaker and the magnetic field reduced to the pole are linearly related. The first results from the flat Stockholm area, obtained with the airborne system of the Geological Survey of Sweden, indicates that most anomalies follow valleys with sedimentary infill. Coincident magnetic highs are interpreted as due to underlying greenstones, that are highly magnetic.

Hydromorphogeological investigations in a typical khondalitic terrain using remote sensing data

In order to examine the influence of tectonic and morphological characteristics on the occurrence and movement of ground water in Khondalitic (garnetiferrous sillimanite gneiss) suite of rocks, hydromorphogeological studies were carried out in a typical Khondalitic terrain situated in Viziangaram district of Andhra Pradesh, India. Different land forms have been identified with the aid of visual interpretation of Landsat imagery together with ground truth data in order to prepare hydromorphogeological and lineament maps. Drainage map and topographic slope map have been prepared using toposheets. These maps and other collateral data like well yields and geophysical data have been analysed to evaluate the ground water prospective geomorphic units. Ground water prospect areas are located in shallow buried pediplains and wash plains in such a way that they are identified on gently sloping uplands situated between the lineaments. Non potential areas are those, which are, low-lying areas near the streams and high slope areas near the residual hills. It is found near low lying areas i.e., beneath the streams that the khondalite must have transformed itself into kaoline and acting as barrier evidently preventing lateral movement of ground water forcing it to accumulate in flat upland areas between two streams or lineaments. From the lithologic cross sections it is found that there are four distinct subsurface layers namely (1) top soil, (2) highly weathered khondalite (kaolinised layer), (3) moderately weathered and fractured khondalite (aquifer layer) and (4) basement of granitic gneiss.

EMG variability during maximum voluntary isometric and anisometric contractions is reduced using spatial averaging

Electromyography (EMG) is a commonly used tool that can be plagued with poor signal-to-noise ratios. One result of poor signal-to-noise ratios is increased within- and between-subject variability of quantified EMG variables, for example, the integrated EMG. Methods that reduce within- and between-subject variability of quantified EMG variables can increase the statistical power of an experimental design and aid in the functional interpretation of experimental results. The purpose of this investigation was to determine the effectiveness of spatially averaging the surface EMG signal to reduce the variability of the quantified EMG obtained during maximum voluntary contractions (MVC). The present study extends the work of earlier investigators describing the enhanced signal characteristics obtained by spatially averaging the surface EMG measured during submaximum voluntary isometric contractions and stretch reflexes. Ten subjects performed maximum voluntary isometric and anisometric (concentric and eccentric) contractions of the elbow flexors. Four electrodes, forming two pairs of bipolar electrodes were placed over both the biceps brachii and brachioradialis muscles. Four rectified and integrated EMG signals from the electrode array were compared. Data from each subject's contraction condition and from each muscle were used to compute a coefficient of variation that was considered representative of the within-subject variability. These data were analysed with a multifactorial repeated measures analysis of variance (ANOVA). The results revealed a muscle-specific, statistically significant superiority of one of the methods in reducing the variability of the rectified and integrated EMG signal. Summing the rectified and integrated signals from each bipolar pair of electrodes in the array was shown to reduce significantly the within-subject variability.

The modelling of direct current electric potential in an arbitrarily anisotropic half-space containing a conductive 3-D body

A new approach to the computation of the D.C. potentials in an arbitrarily anisotropic half-space in which there is embedded a 3-D equipotential (perfect) conductor is presented. With the aid of a Fredholm's integral equation of the first kind developed for the potential, the problem is formulated in which the unknown function is the normal component of the current density on the surfaces of the conductor and it is solved numerically by means of a method of subareas. A Green's function for the point source potential in the arbitrarily anisotropic half-space is the kernel of the integral equation, which is developed by a new method. The integrated Green's function defined for the integral calculation of the subareas can be calculated using a one dimension analytical method followed by another multi-dimensional numerical approach when the body is represented by the cube cell accumulation method, in which the cell surfaces are parallel to the Cartesian coordinate system. The effects of the arbitrary anisotropy and the conductive body on the electric potential are illustrated with the aid of several numerical examples, where the point current source is located at different positions in the half-space. Forward modelling of the nature shown in this paper is valuable as an interpretation aid. An extension of this work to the cases of typical field survey geometries is relatively straight forward.

The impact of a picture archiving and communication system on nuclear medicine examination interpretation.

Radiographic correlation is essential for many of the examinations performed in nuclear medicine. The purpose of this study was to evaluate the impact of a picture archiving and communications system (PACS) on the function and efficiency of a nuclear medicine department at a tertiary care institution. We evaluated 250 consecutive noncardiac nuclear medicine imaging examinations and asked the interpreting physician the following questions: (1) Was PACS used in the interpretation of the study? (2) Did the use of PACS expedite examination completion or aid in study interpretation? And (3) Did the use of PACS permit a definitive diagnosis to be made? PACS was accessed for correlative radiographic images in 155 of the 250 (62%) nuclear medicine examinations. Images available on PACS for review aided in study interpretation in 74% (115 of 155) of cases. The use of PACS was thought to expedite examination completion in 55% (86 of 155) of cases. The system was accessed but not operational in only 1% of cases (2 of 155). PACS provides reliable, rapid access to multimodality correlative radiographic images that aid in the interpretation of nuclear medicine examinations. Such systems also increase the efficiency of a nuclear medicine service by allowing timely and conclusive interpretations to be made.

SIR‐C/X‐SAR multifrequency multipass interferometry: A new tool for geological interpretation

Radar remote sensing is a tool of increasing importance in the study of volcanic sites. Synthetic aperture radar (SAR) is a high‐resolution imaging tool used to survey areas which are not practical or safe to be directly inspected. With the introduction of the across‐track SAR interferometry (IFSAR) technique, digital elevation models (DEM) can be produced. The usefulness of such interferometric products depends on the ability to extract information that can be used for geological interpretation. We analyzed the shuttle imaging radar C (SIR‐C)/X‐SAR multifrequency multipass interferometry mission over Mount Etna, Sicily, and we performed a supervised geological interpretation of the coherence maps and a fractal‐based analysis of the IFSAR DEMs. The first permits us to recognize different volcanic terrain and to distinguish between vegetated and unvegetated areas, while the second allows us to validate the IFSAR DEMs and to detect large‐scale geological features. This latter analysis, performed over the photogrammetric DEM, enabled us to recognize artifacts caused by digitizing and resampling. Obviously, IFSAR DEMs are not affected by these problems. As a consequence, IFSAR products are a valuable aid in geological interpretation.

CONTRIBUTION OF THE MOLECULAR GENETICS LABORATORY TO THE EVALUATION OF THE PERSISTENTLY HYPOTONIC INFANT. † 872

Pediatricians may be requested to elucidate the cause of nonspecific persistent generalized infantile hypotonia. Among the many causes in the differential diagnosis of a floppy baby are several familiar genetic diseases that can present with generalized hypotonia in the newborn period. Testing for these disorders, spinal muscular atrophy (SMA), myotonic dystrophy (DM) and Prader-Willi Syndrome (PWS), now requires only a small amount of peripheral blood, and positive results are diagnostic for that disease. The tests for SMA, DM, and recently PWS are done by DNA analysis to look for gene deletions(SMA), expansions (DM), or the absence of the paternal copy of chromosome 15(PWS). Previous analysis for PWS, including this study, has been done by chromosome fluorescence in-situ hybridization to look for deletions in the PWS region of chromosome 15. This technique can detect approximately 70% of those with PWS. Screening of 35 persistently hypotonic children for one or more of these three disorders revealed 7 positive results, 2 with DM, 1 with SMA and 4 with PWS, for a detection rate of 20%. In addition, in 8 of 8 cases in which a clinical diagnosis of SMA had been made, DNA analysis was used to confirm the diagnosis, aid in interpretation of prenatal results in subsequent pregnancies, or provide a conclusive diagnosis, without the need for a muscle biopsy. Positive findings for one of these genetic diseases can provide valuable information regarding clinical management and prognosis of the child, allow specific prenatal testing in future pregnancies and could lead to the identification of other at-risk relatives. Twenty per cent of hypotonic infants were found with one of these three genetic disorders, illustrating the significance of considering this panel of diseases in an infant presenting for genetic evaluation with nonspecific hypotonia.

Performance Characteristics of Seven Nutrition Label Formats

The authors evaluate seven nutrition label formats to determine consumer comprehension and acceptance of displayed information. They test comprehension on five tasks: comparing two products, judging healthfulness, verifying claims, estimating servings needed to meet the daily requirement for a nutrient, and balancing nutrients in a daily diet. Performance scores were higher on some tasks—particularly dietary management ones—for formats that displayed nutrient amounts in percentages than for those that displayed nutrient amounts in metric units, even when interpretational aids were included on the metric formats. The two most preferred formats were metric formats with an interpretational aid. The findings have an important impact on decisions about the final nutrition label format required by the Food and Drug Administration.

Photodegradation of wool keratin: Part I. Vibrational spectroscopic studies

The photodegradation of wool keratin is a very complex process that is not well understood. In this work the techniques of Fourier transform Raman and attenuated total reflectance Fourier transform-infrared spectroscopies have been used to study wool samples irradiated in air using a variety of different sources. The spectra obtained from these samples have been compared with those obtained from wool treated with sodium bisulphite, a reagent well known to produce thiol and S-sulfonate groups. As an aid for spectral interpretation the Raman and infrared spectra of cystine and those of the sodium and potassium cysteine-S-sulfonates have also been obtained. The data suggest that there are two different photolytic reaction pathways involving the cystine residues which are dependent on the wavelength of the applied radiation. © 1996 John Wiley & Sons, Inc.

Interpretation of bioassay results. Species, sex, and tumor-site specific carcinogenic effects in long-term studies in rats and mice.

Correlation among species, sex, and tumor-site of neoplastic responses in 25 chemicals tested for carcinogenicity at the An-Pyo Center in 1981-1993 were evaluated. Of the 25 chemicals tested in rats and mice, 44 percent (11 of 25) were positive in at least one species and 56 percent (14 of 25) were negativein both rats and mice. Rats and mice exhibited a similar sensitivity to carcinogens as evidenced by 8 positive studies in rats and 9 positive studies in mice for a total of 17 positive studies. Three of the 25 chemicals evaluated were genotoxic and all tested positive in the carcinogenic bioassays in all groups and in both species and sexes. In addition, target tissues were similar between males and females. However, species specific or sex-related responses were evident at different dose levels with the non-genotoxic compounds tested. Compilation ofhistorical tumor development data has revealed biological mechanisms whereby three classes of compounds produce characteristic positive results in rodent bioassays. Criteria for defining genotoxic, non-genotoxic and promotor/pseudo-carcinogens are presented and discussed. Results of current bioassays together with mechanistic and refined, short-term studies may be evaluated collectively to aidin interpretation of results and in the mechanistic identification of these three classes of compounds.

The filtering effect of orbit correction on geopotential errors

The geophysical interpretation of satellite tracking residuals generally ignores the filtering effect of initial orbit correction on the true errors of the model. While the filtered information is usually regarded as lost, knowing the spectral characteristics of the filter is a great aid in the detailed interpretation of residuals, especially of global data sets. In this regard, we derive the filter characteristics (admittances) of orbit correction in the presence of geopotential-caused trajectory errors. We then apply the filter to determine the likely power of the lost radial information in crossover differences of sea heights determined from satellite altimetry or in the latitude lumped coefficients derived from them. For example, we find that resonant geopotential information with periods longer than the corrected orbit's arc length is largely lost in residual crossover data. Results are given for GEOSAT, ERS-1 and TOPEX/Poseidon in their Exact Repeat Missions, using calibrated variancecovariance matrices of the harmonic geopotential coefficients of several recent Earth gravity models. To prove that filtering is important, we first employed a simple cut of all perturbing terms with periods longer than the general tracking period (4 days for GEOSAT and ERS-1, and 10 days for TOPEX). But the cut is too crude a method from a theoretical viewpoint, and thus, we developed two new filters. A comparison of their admittances explains the differences (and sometimes anomalous behaviour) between them and the cut. Many numerical examples (single-satellite crossover errors and latitude lumped coefficient errors, as projected from the variance-covariance matrices) are presented. This paper has been presented during the Panel on Satellite Dynamics, at COSPAR 1994, in Hamburg, Germany.

Origin and History of the Thematic Apperception Test Images

The origin and history of each of the images appearing on the 1943/1971 edition of the Thematic Apperception Test is presented. This information corrects and supplements that provided by Murray (1943/1971) in the test manual. Authorship of the test, including the contributions of Christiana Morgan, is discussed. The material presented expands the historical record and may serve as an aid in test interpretation.

Application of Euler Deconvolution and a Neural Network System as Interpretation Aids for Three Component Downhole Tem Data

The relationship between the secondary field due to a TEM source and a dipolar potential field has been documented (Dyck and West, 1984; Grant and West, 1965). In light of this relationship it is possible to utilise potential field interpretation aids when dealing with TEM data. Where only the axial component of the anomalous field is available, in the case of downhole TEM data, the implementation of these techniques is very restricted and may yield ambiguous model parameters, hence alternative techniques must be considered. Euler deconvolution may be used to obtain the approximate coordinates of the source even in the presence of an overburden response. A neural network system has been trained to output the dip and strike direction of a plate model using scaled field data as input. Utilising both the neural network and Euler deconvolution techniques, approximate model parameters may be computed directly from the field data. Synthetic examples are presented, showing that these techniques are applicable even in the presence of noise and conductive overburden. A field example from the Flying Doctor prospect is also presented. The computed model parameters were found to be consistent with previously published data (Cull, 1993).

Radar inspection of civil engineering structures : Hobbs, C P; Temple, J A G; Hillier, M J Non-destructive Testing in Civil Engineering, Liverpool (United Kingdom), 14–16 Apr 1993. Vol. 1, pp 79–96. Edited by J H Bungey. The British Institute of NDT (1993)

Seismic radar has been used as a geophysical tool for mineral exploration since the 1970's. Ground probing radar has been used in many applications world-wide. In the United Kingdom, radar became an established tool in the investigation of a sub-standard block of flats at Ronan Point in 1984. An advantage of radar is that it can be used to scan whole areas at an acceptable speed. However, despite the potential of radar, the civil engineering community in the UK has been slow to adopt the technology. This is partly because some claims about the capabilities of radar have been overstated, and also because the data currently generated can be difficult for the non-specialist to understand. The work (the authors all work at the National NDT Centre at Harwell) has used two approaches to address these specific problems. First, signal processing combined with a well-defined inspection procedure has been used to produce clearer images. Second, modelling of assumed subsurface structure is carried out to yield theoretical images which can be used to optimise inspections and aid in interpretation of real datafiles. The advantages to typical radar data are demonstrated by example. (A) For the covering abstract see IRRD 861706.

Microbiological collaborative studies for quality control in food laboratories: Reference material and evaluation of analyst's errors

Working groups of the Federal Health Office in Germany and of the International Dairy Federation (IDF) have developed a quality assurance system to assess the analyst performance for colony count methods. The experiment design consists of several dilution series produced from a homogeneous sample suspension. Each series contains a number of twofold dilution steps with parallel plates on each level. The structure of this design permits a detailed analysis of the total variance and identification of analysts' methodological errors as single effects. A computer-based interpretation aid may classify the laboratory as working in correspondence with good laboratory practice (‘acceptable’) or, otherwise, furnishing ‘to good’ or ‘unacceptable’ results. Some examples are given for deviation depending on individual faults. Both, internal quality assurance and collaborative studies demand suitable reference samples. The reference material used has to meet certain requirement concerning homogeneity, contamination level and microbiological stability during a period of storage and transport. A naturally contaminated sample material was prepared, which has been used successfully in microbiological collaborative studies.

Hochon’s Arrow: The Social Imagination of Fourteenth-Century Texts by Paul Strohm

REVIEWS them. It is fitting, therefore, that the last visual image analyzed by the author is that ofCriseyde quaking like an aspen leaf in Troilus's arms. In Stillinger's eloquent words, "She is like a page being bound into a book" (p. 211), a page that lends itselfto infinite glossing since Criseyde herselfis an enigma. Troilus, the narrator, Pandarus, and all the "olde clerkes" that wrote her story attempt to define her once and for all, to fold her shut, as it were, in the interests ofclosure demanded by the form ofthe book and by patriarchal social structure. As "a shifting signifier" (p. 215) Criseyde is the center of a postmodern, unstable subjectivity, whereas Troilus prefigures the modern masculine self, unified and disengaged from the shifting con­ texts that surround him. Yet by the poem's end the form ofTroilus and the form oflyric are no longer the locus of privilege but rather oftroubling fictions. In so doing, Chaucer gives his readers the freedom not only to identify with his characters or to remain unmoved but also to see his own struggle as a poet who stands alone and original (like Troilus), or derivative and culturally programmed (like Criseyde). The Song of Troilus, despite or perhaps because of its shifting concerns and densely argued issues, is an important contribution to medieval studies, particularly to the scholarship on Chaucer and the Italian Trecento. The complexity ofthe questions posed and the occasionally impressionistic manner ofanswering those questions may prove too daunting for under­ graduate readers. Despite its flaws, it is a stimulating scholarly text that dares to present original and novel ideas that will be ofinterest to every specialist in the field. CARON ANN CIOFFI University ofCalifornia, Davis PAUL STROHM. Hochon's Arrow: The Social Imagination ofFourteenth-Century Texts. App. by A. J. Prescott. Princeton, N.J.: Princeton University Press, 1992. Pp. xii, 128. $37.50 cloth, $12.95 paper. Paul Strohm's book consists ofseven substantial essays dealing mainly with London affairs in the period between 1380 and 1400, two appendices (one by A.J. Prescott), and a briefintroduction setting out the principles which underlie his approach. He writes: "At the center ofmy inquiry is the text itself, with the cryptic and paradoxical information it both offers and with293 STUDIES IN THE AGE OF CHAUCER holds. And the text is characteristically viewed within a larger field or 'environment' of previous and contemporary texts, visual representations, pageants, social dramas, and political acts" (p. 6). A little later he says, "An environment embraces not just words and textual conventions, but also schemes or structuring ideas functioning at an intermediate level ofgener­ alization" (p. 6). His normal procedure is to set and test one text against others, exposing hidden assumptions and ideologies, and in doing so he collapses somewhat the distinctions between what is "fictional" and what is a record offact, what is "literary" and what is "historical." The approach in general owes much to New Historicism, but other models are also used from time to time. Most ofthese essays bear, in one way or another, on Chaucer, Gower, and Thomas Usk, authors to whom Strohm has already devoted much scholarly attention, but the first two chapters focus on historical events. "Hochon's Arrow" deals centrally with the mayoral elections in London on October 13, 1384, and the threats of violence which accompanied them. A brief narrative by John Banham telling how he prevented Hochon of Liverpool from shooting Hugh Fastolf, one of the supporters of the victorious Nicholas Brembre, as he urinated against the wall of St. Lawrence's Church, provides the author with a way into a discussion of the factional­ ism of London city politics. These were essentially the "politics of space," he argues, and uses anthropological ideas about marking behavior as an interpretive aid. Though the initial incident itselfis fairly trivial and noth­ ing happened, the approach and discussion are illuminating. Interesting too is the chapter on the Revolt of 1381, where Strohm invokes Bakhtinian ideas about "carnival," misrule, and the (temporary) overturning of orthodoxy to help to identify the "rebel voice" (p. 51) and something of the ideology of the rebels. He sees significance in the Monk of...

Two-Dimensional Synthetic Seismic and Log Cross Sections from Stratigraphic Forward Models

In an effort to fully use deterministic stratigraphic forward-modeling techniques in subsurface stratigraphic analysis, we developed a computer interface to routinely create synthetic logs and one-dimensional and two-dimensional (2-D) seismic responses from 2-D stratigraphic simulations. Each 2-D stratigraphic model can contain up to 200 timelines defining age-equivalent stratigraphic layers with laterally variable lithofacies and depths. Synthetic gamma ray, density and velocity responses are calculated for the simulated lithofacies using user-specified rock and fluid properties. Vertically incident synthetic seismograms are created using calculated reflection coefficients and user-defined input wavelets. Because stratigraphic simulations provide chronostratigraphy as a nown, log correlations and the interpolated seismic geometries follow timelines exactly. The power of this technique as an aid in sequence stratigraphic interpretations is shown from three examples: (1) a simulation of an idealized clastic system assuming constant clastic input and sinusoidal fourth-order and third-order sea level variations, (2) a detailed simulation of one third-order carbonate depositional sequence (lower-middle San Andres Formation) from the Northwest shelf, Permian basin, and (3) simulations of the Permian mixed clastic-carbonate infill of the Midland basin. Some general conclusions from these examples include the following: (1) seismic and well log-defined topsets, foresets, bottomsets, and related event terminations can be directly related to relative sea level fluctuations, (2) Exxon-type sequence boundaries (i.e., unconformities) are not necessarily seismically imageable, and their identification on well logs is not straightforward, and (3) lateral variations in amplitude related to lithofacies variations can be modeled. Synthetic logs and seismic sections from stratigraphic forward models such as these may be useful in constraining interpretations of subsurface data and thus aiding the prediction of reservoir and seal.

Computer-aided analytic and visualization tools for atructural studies

Structural biologists typically acquire data in the form of a two-dimensional image (or set of images) from which the three-dimensional structure of the object of interest must be inferred. Examples can be found over a range of sizes spanning many orders of magnitude, and covering structures from the macroscopic to the atomic scale. A correspondingly wide range of different instruments is used in the collection of this data, from CT/MRI scanners, through light and electron microscopes, and recently, atomic force instruments. The images which are collected from these instruments may be in the form of a series of 2D slices through the 3D data set (and these may be either physical sections or optical sections) or a series of to mographic 2D projections of the 3D dataset. In either case it is highly likely that computer software tools will be used on the data set eitheras an aid in the qualitative interpretation of the structure or as a means of extracting quantitative morphological measurements.

Evaluating Results Using Corrected and Uncorrected Effect Size Estimates

AbstractMagnitude-of-effect (ME) statistics, when adequately understood and correctly used, are important aids for researchers who do not want to place a sole reliance on tests of statistical significance in substantive result interpretation. We describe why methodologists encourage the use of ME indices as interpretation aids and discuss different types of ME estimates. We discuss correction formulas developed to attenuate statistical bias in ME estimates and illustrate the effect these formulas have on different sample and effect sizes. Finally, we discuss several cautions against the indiscriminate use of these statistics and offer reasons why ME statistics, like all substantive result interpretation aids, are useful only when their strengths and limitations are understood by researchers.

Theoretical Analysis of Relaxation During Shaped Pulses. I. The Effects of Short T1 and T2

A detailed theoretical treatment of spin-lattice and spin-spin relaxation effects which occur during the application of long selective pulses is presented. The effects of T1 and T2 on the degradation of the frequency-domain profile are discussed for a wide variety of pulse shapes. The predicted effects are observed experimentally for residual HOD in a 2:1 (v/v) mixture of DMSO/D20. The relaxation effects for a given pulse are dependent on the ratio of pulse length to relaxation time, and differences between pulses are due to the trajectories of the magnetization produced by each pulse envelope. A comparison of the various pulse shapes is presented for aid in experimental design and data interpretation.