Showing papers by "University of New Mexico published in 1980"

Transient Response of Multiconductor Transmission Lines Excited by a Nonuniform Electromagnetic Field

Abstract: The time-domain transmission-line equations for uniform multiconductor transmission lines in a conductive, homogeneous medium excited by a transient, nonuniform electromagnetic (EM) field, are derived from Maxwell's equations. Depending on how the line voltage is defined, two formulations are possible. One of these formulations is considerably more convenient to apply than the other. The assumptions made in the derivation of the transmission-line equations and the boundary conditions at the terminations are discussed. For numerical calculations, the transmission -line equations are represented by finite-difference techniques, and numerical examples are included.

Prehepatic Insulin Production in Man: Kinetic Analysis Using Peripheral Connecting Peptide Behavior*

Abstract: The prehepatic production of insulin in normal man was evaluated by kinetic analysis of connecting peptide (C-peptide) behavior in the plasma in men and women. Studies were performed during suppression of endogenous insulin secretion (induced by both fasting and exogenous insulin injection) as well as during stimulation of secretion (induced by oral glucose ingestion) and iv glucose injection. Least squares spline fitting of the C-peptide data by interactive computer analysis permitted evaluation of the precursor production of insulin using a two-compartment model for C-peptide removal. Basal prehepatic insulin production averaged 15-4 mU/70 kg.min in 20 subjects and was reduced to 0.9 +/- 2.2 mU/70 kg.min after 84 h of fasting. The injection of exogenous iv insulin resulted in suppression of endogenous production to 0 +/- 2.5 mU/70 kg.min. Maximum prehepatic insulin production induced by a 100-g oral glucose tolerance test was 91 +/- 1.2 mU/70 kg.min, with a cumulative hormone secretion of 11.4 +/- 2.0 U over the 5 h of observation. After the acute iv injection of 25 g glucose, production rose to 465 +/- 108 mU/70 kg.min at 2 min post injection and rapidly returned toward basal. Levels of insulin in the portal vein calculated from this analysis were markedly elevated relative to simultaneous peripheral venous levels. These results quantitate prehepatic insulin production and portal venous insulin concentration from an analysis of the behavior of C-peptide within the plasma in both the steady state and the nonsteady state in man.

Feeding patterns of monophagous, oligophagous, and polyphagous insect herbivores: The effect of resource abundance and plant chemistry

Abstract: Leaf tissue preferences of monophagous, oligophagous, and polyphagous insect herbivores were determined using young and mature leaf tissue abundances and herbivore feeding observations. Larvae of monophagous and oligophagous herbivores preferred young leaf tissues while, overall, larvae of polyphagous species preferred mature leaves of their various host plants. Even though a species is often polyphagous over its geographical range, larvae from local populations may be very specialized in their diet. When this occurs these specialized larvae prefer the more nutritious and perhaps more toxic young leaves of some of their host plants. Resource abundance and plant chemistry are discussed as major factors influencing herbivore feeding patterns.

Transient response of multiconductor transmission lines excited by a nonuniform electromagnetic field

Abstract: The time-domain transmission-line equations for uniform multiconductor transmission lines in a conductive, homogeneous medium excited by a transient, nonuniform electromagnetic (EM) field, are derived from Maxwell's equations. Depending on how the line voltage is defined, two formulations are possible. One of these formulations is considerably more convenient to apply than the other. The assumptions made in the derivation of the transmission-line equations and the boundary conditions at the terminations are discussed. For numerical calculations, the transmission -line equations are represented by finite-difference techniques, and numerical examples are included.

Thickness of facial tissues in American blacks.

Abstract: The production of a three-dimensional plastic face on a human skull has been practiced sporadically since the latter part of the last century. In recent years, the technique has been revived and applied to forensic science cases. Contemporary facial reproductions are based on a small sample collected before the turn of the century. In this paper, we present data on a heretofore unstudied segment of Homo sapiens, the American black. Facial tissue thicknesses for this group vary greatly from those previously reported in European whites and in Japanese. Use of these data should make possible more accurate facial reproductions on the skulls of American blacks.

Ultrastructure of secondary neurulation in the chick embryo

Abstract: Formation of the future lumbosacral level of the spinal cord was studied in two-day-old chick embryos by light and electron (transmission and scanning) microscopy. A neurulation overlap zone occupied this level. The dorsal portion of the neural tube formed by bending of the neural plate and approximation and fusion of neural folds (i.e., by primary neurulation), and the ventral part formed during secondary neurulation by cavitation of an initially solid, compact mass of cells, the medullary cord, derived from the tail bud. Secondary neurulation involved four morphogenetic processes: (1) segregation of the cells of the prospective medullary cord from cells of adjacent regions, (2) formation of a precisely delimited medullary cord, (3) cavitation of the central portion of this cord, and (4) coalescence of all lumina into a single, central cavity. Cell segregation was associated with the formation of a layer of primarily extracellular materials between adjacent organ rudiments. The source and composition of these materials are unknown. Formation of the medullary cord entailed considerable elongation of the peripheral cells of this developing structure and the fabrication of small intercellular juctions, first at the basal (outer) ends of the elongating peripheral cells, and then at their apical (inner) ends. These arranged, columnar cells, having characteristics similar to those of the neural plate, and an inner cluster of irregularly shaped and arranged cells. Cavitation always occurred first at the junction between these two cellular populations. The central cells of the medullary cord also eventually elongated, like the peripheral cells, and may have been intercalated into the lateral walls of the developing neural tube as lumina coalesced.

Buffering of silica and phosphate in a turbid river1

Abstract: The buffering of riverine dissolved silica and phosphate by sorption reactions between the aqueous phase and suspended secliment is examined with the turbid Colorado River system as a model. Concentrations are found to lie in a range predicted from laboratory sorption experiments with natural sediments and waters. Phosphate is probably highly buffered by suspended sediment during river flow while silica is not. Silica appreciably affects phosphate sorption reactions but not vice versa. Increased temperature results in higher silica but lower phosphate concentrations as a result of sorption. The buffering action of suspended sediments is largely complete within a few hours and is approximately proportional to the concentration of suspended sediment. Of prime concern in the study of nutrient dynamics in natural waters are the factors governing the availability of various nutrients to biotic uptake. This availability is often related to the concentrations of nutrients, which in certain systems are strongly affected by chemical interplay between their dissolved forms and mineral surfaces. Adsorption/desorption reactions involving common soil and sediment materials can exert a strong influence on the partitioning of silica and phosphate between solid and aqueous phases in periods of hours to days (e.g. Edzwald et al. 1976; Kennedy 1971). Such rapid partitioning could exert significant influence on the nutrient flux through a river system with high concentrations of suspended materials. The presence of labile silica and phosphate sorption sites on the suspended sediment should therefore provide a buffer capacity for the dissolved forms of these species. Our study focuses on the turbid Colorado River system above present-day 1 This work was supported in part by grants NSFRANN AEN 72-03469 AO3 and GI-34831 Al. z Present address: New York Cooperative Fishery Unit, Department of Natural Resources, Fernow Hall, Cornell University, Ithaca, New York 14853. Lake Powell (Fig. 1). The reservoir (occupying about 300 km of the former Colorado River) was formed by Glen Canyon Dam in 1963. Most of the water delivered to this region derives from snowmelt in the mountains of Colorado and Wyoming during spring runoff. The seasonal variation of flow has been partially damped by the construction of reservoirs upstream of Lake Powell in the early 1960s. Historically, average water flows through this region are of the order of 1-2~ lOlo rn”. yr-I. Suspended sediment concentrations in the Colorado River system commonly reach several thousand milligrams per liter. The bulk of the sediment load in the system originates in the Colorado Plateau rather than in the mountains from which the water comes (Iorns et al. 1965). The suspended sediment consists primarily of illite, kaolinite, smectite, quartz, feldspar, calcite, and dolomite, reflecting the largely Mesozoic sedimentary rocks which are their provenance (Mayer 1973; Kennedy 1965). Evidence for the buffering of silica in river systems has been summarized by Edwards and Liss (1973). That this phenomenon has occurred in the Colorado River is shown in Fig. 2, in which weighted mean annual concentrations of silica and chloride in the Colorado River

Gliogenesis of astrocytes and oligodendrocytes in the neocortical grey and white matter of the adult rat: electron microscopic analysis of light radioautographs.

Abstract: The identification of newly formed glial cells in the normal adult cerebral cortex is unresolved, since the identification of cells incorporating [H3] thymidine has not been demonstrated in the adult by electron microscopy. In the present study, this problem has been studied by combining the resolution of the electron microscope with radioautography of 1-micrometer sections. Four normal male rats were injected at 90 days of age with [H3] thymidine and allowed to survive for 30 days. Labeled cells were found in 1-micrometer sections of the visual cortex of these adult rats, and electron micrographs of selected cells from these same sections demonstrated clearly two types of cells labeled, astrocytes and oligodendrocytes, in both grey and white matter. The few cells that were tentatively identified as labeled microglia in the light microscope proved to resemble oligodendrocytes when examined in the electron microscope. In 1-micrometer sections of the cortical grey matter, heavily labeled astrocytes (13 or more silver grains over the nucleus) represent about 0.08% of the total astrocytic population, and heavily labeled oligodendrocytes also were about 0.08% of their population. In the cortical white matter, about 0.03% heavily labeled astrocytes were observed, compared to about 0.07% heavily labeled oligodendrocytes. For all neuroglial cells in both white and grey matter, the average percent heavily labeled cells was 0.066%, a value large enough to suggest a slow turnover of neuroglial cells during the lifespan of the rats.

Syntax: A Linguistic Introduction to Sentence Structure

Abstract: Part 1 Constituent structure: constituent structure form classes constituent structure grammar formal grammars verbs and nouns adjectives and prepositions optional constituents intermediate levels of structure embedding, recursion and ambiguity relations between sentences the sentence. Part 2 Morphology: words and morphemes morphemes and morphs the morphology of the English verb lexical morphology form classes and grammatical categories. Part 3 Functional relations: heads and modifiers - the encoding of dependency relations processes and participants grammatical functions sentences in texts.

Sperm Autoantigens and Fertilization. I. Eftects of Antisperm Autoantibodies on Rouleaux Formation, Viability, and Acrosome Reaction of Guinea Pig Spermatozoa

Abstract: Fab and IgG were isolated from the sera of 1) guinea pigs immunized with their own epididymal spermatozoa or testis homogenate in complete Freund’s adjuvant, or 2) normal guinea pigs. Their effects on rouleaux formation, the viability, and the acrosomal reaction of guinea pig epididymal spermatozoa were studied in vitro. Monovalent (Fab) antibodies to epididymal spermatozoa and testis homogenate, but not Fab of normal guinea pig serum, rapidly dispersed sperm rouleaux in a dosedependent and time-dependent manner. The effect was reversed by the addition of epididymal spermatozoa and was prevented if the Fab antibody was previously absorbed with guinea pig spermatozoa but not with guinea pig spleen cells or Mycobacterium tuberculosis. Compared with spermatozoa in Fab of normal guinea pig serum, the dispersed spermatozoa were less viable, and the rate of acrosomal reaction was significantly reduced. Contrary to expectation, bivalent (IgG) antibody to epididymal spermatozoa did not agglutinate sperm rouleaux. It prevented head-to-head agglutination of sperm rouleaux and significantly prolonged sperm viability. Most significantly, the acrosome reaction was completely inhibited in the presence of 3.2 X 10’ antibody molecules (to surface antigens of guinea pig spermatozoa) per spermatozoon. The results strongly implicate 1) guinea pig sperm and testicular cell surface autoantigens in the cell adhesion phenomenon leading to rouleaux formation, and 2) guinea pig sperm surface autoantigens in the induction of capacitation and/or acrosome reaction. We further suggest that, in the guinea pig; sperm rouleaux prevent premature acrosome reaction

Variables Affecting Guilty Pleas and Convictions in Rape Cases: Toward a Social Theory of Rape Processing

Abstract: Previous research on reactions to rape has been flawed by methodological and theoretical problems that have prevented a reliable assessment of detenninants. I argue that the likelihood of convictions in rape cases will be affected by the extent to which characteristics of cases approximate the stereotypes of rape held by criminal justice personnel. I assume that rape stereotypes are related to perceptions of the victim's and defendant's moral character and to characteristics of victims, defendants, and offenses. I relate these variables to the likelihood of guilty pleas and verdicts for 124 rape cases filed in criminal court in a large, midwestern city. Multiple regression analysis showed that net of the effects of evidence, black women, women who allegedly engaged in misconduct, women acquainted with the defendant, and women who did not report the incident promptly were less likely to have their complaints come to trial and result in conviction. Also, assaults by defendants with more serious records and assaults by more than one man were likely to end in conviction. Results were consistent with the proposition that reactions to rape are conditioned by stereotypes abozTt the kind of women, men, and social situations most typical of rape.

Diminished Immune Response in Sun-Damaged Skin

Abstract: In previously sensitized volunteers, higher concentrations of 2,4-dinitrochlorobenzene were necessary to elicit positive patch test reactions on the sun-damaged skin of the neck than on the protected skin of the upper part of the back. This difference was not found in subjects without evidence of sun damage, and there was no difference between sun-damaged and nondamaged skin in response to a primary irritant. Responses to intradermally injected common antigens were also less intense in sun-damaged skin that in nonexposed skin. These findings suggest the existence of a local defect in cell-mediated immunity in skin altered by long-term sun exposure.

Temporal variation in habitat structure and shrubsteppe bird dynamics.

Abstract: We investigate the role of temporal variation in habitat physiognomy in influencing the dynamics of shrubsteppe bird populations and communities. During a 3-y (1977–1979) study of 14 sites in the northern Great Basin of North America, annual precipitation varied substantially, with one of the driest years on record followed by one of the wettest. This resulted in significant physiognomic variation (increasing height and coverage of vegetation, decreasing horizontal patchiness), mediated largely by changes in the annual elements of the flora, particularly forbs and grasses. Shrub species coverage values, on the other hand, demonstrated no statistically detectable year-to-year changes, nor were they correlated with any physiognomic variation. Despite large scale physiognomic changes, no bird species' abundance varied in a statistically significant fashion; neither could variation in bird abundances be correlated with variation in either physiognomy or shrub species coverages. Multivariate analyses revealed essentially the same patterns as the univariate analyses: substantial changes in physiognomy, few changes in shrub species coverages or bird species abundances, and little correlation of temporal variation among the three data sets. Calculation of the Euclidean distances that sites “moved” in multivariate physiognomic, bird species, or shrub species hyperspaces yields synthetic gradients of annual “turnover” of sites with respect to those data sets. Sites identified as demonstrating high physiognomic turnover were characterized by high coverage of grass and forbs, while low turnover sites had greater coverage of shrubs and higher shrub species diversity. Relatively high bird turnover sites had greater numbers of Western Meadowlarks and Black-throated Sparrows, while more stable sites had high numbers of Brewer's Sparrows. Physiognomically, high bird turnover sites were grassier and had greater total vegetation coverage, while low bird turnover sites had more bare ground and higher horizontal patchiness. A site's position on the avifauna turnover axis, however, was uncorrelated with its position on the physiognomic turnover axis. Shrub species showed virtually no annual turnover. Reanalysis of a previous Principal Components Analysis (PCA) of these same data sets that was applied without regard to year of sampling revealed that the first physiognomic component (41% of the total physiognomic variability) did in fact have a strong temporal element, and that this element was consistent with the changes in univariate characters noted above. No other physiognomic component could be associated with annual variation, nor could any components of parallel bird abundance or shrub species coverage PCA's. Regional patterns indicate that sites tended to be very consistent from year to year in their relationships to one another as defined by their relative locations in either physiognomic or shrub species hyperspaces, but varied independently of one another with respect to their bird species abundances and composition. Examination of the temporal consistency of site relationships between “bird space” and “vegetation space” reveals that bird communities are to a large degree independent of a site's physiognomic position, but instead are strongly associated with its position in shrub species hyperspace. The overall patterns that emerge from these analyses are consistent with the so-called “checkerboard effect” that results from the apparently random annual redistribution of individual birds, and leads to the conclusion that populations of shrubsteppe birds are not existing at maximum density or “carrying capacity.” Such observations are consistent with contentions that these populations lack close biological coupling with coexisting species and that interactions among these species (e.g. competition) are likely to play little if any role in the organization of their communities.

Dissolution of salt deposits by brine density flow

Abstract: The origin of collapse structures and breccias that vertically penetrate or occur within impermeable evaporites has never really been understood. The density of the brine that develops as salt deposits are dissolved can generate continuous gravitational brine movement. If the source of the dissolving water is artesian, or continuous, a flow cycle is developed in which the salt itself supplies the density gradient that becomes the vehicle of its own dissolution. The Delaware Basin in western Texas and southeastern New Mexico provides a particularly good example of how brine density flow can produce dissolution chambers that collapse to form breccias. The potential for dissolution by brine flow is an inherent property of partly exhumed evaporites and may constitute a risk factor in the storage of radioactive waste in evaporite deposits.

Artificial intelligence in manufacturing planning and control

Abstract: This paper explores some of the typical problems in manufacturing systems planning and control, particularly those pertinent to the automatic operation, and describes how artificial intelligence methods can be applied. We demonstrate how predicate logic and theorem proving techniques using resolution can be used in a manufacturing environment. Assertions of fact and axioms representing the knowledge required are given in an underlying data base. Illustrative problems demonstrate how user problems, such as assignment of jobs to machines when conflicts occur, can be handled by a decision support system in the framework of resolution in a problem reduction approach.

Audio teleconferencing versus face‐to‐face conferencing: A synthesis of the literature

Abstract: This review examines field and laboratory research comparisons of audio teleconferences and face‐to‐face meetings Summaries of the strengths and weaknesses of each mode for relevant task (eg, problem solving, negotiating, and interviews) and group process variables (eg, person perception and communication climate) provide a basis for selecting the communication mode appropriate to specific communication needs

Low-velocity Gunshot Wounds to Extremities

Abstract: Several therapeutic modalities in the management of low-velocity gunshot wounds to extremities were investigated. Local excision of wound margins, irrigation, and primary or delayed primary closure without the use of the operating room or prophylactic antibiotics produced results which were comparable to those obtained with a more aggressive surgical protocol.