Showing papers by "University of New Mexico published in 1987"

Neutral models for the analysis of broad-scale landscape pattern

Abstract: The relationship between a landscape process and observed patterns can be rigorously tested only if the expected pattern in the absence of the process is known. We used methods derived from percolation theory to construct neutral landscape models,i.e., models lacking effects due to topography, contagion, disturbance history, and related ecological processes. This paper analyzes the patterns generated by these models, and compares the results with observed landscape patterns. The analysis shows that number, size, and shape of patches changes as a function of p, the fraction of the landscape occupied by the habitat type of interest, and m, the linear dimension of the map. The adaptation of percolation theory to finite scales provides a baseline for statistical comparison with landscape data. When USGS land use data (LUDA) maps are compared to random maps produced by percolation models, significant differences in the number, size distribution, and the area/perimeter (fractal dimension) indices of patches were found. These results make it possible to define the appropriate scales at which disturbance and landscape processes interact to affect landscape patterns.

Linewidth broadening factor in semiconductor lasers--An overview

Abstract: The objective of this paper is to present an overview of topics related to one of the fundamental parameters for semiconductor lasers-the linewidth broadening factor α that describes the coupling between carrier-concentration-induced variations of real and imaginary parts of susceptibility. After introducing the definition of α and discussing its dependence on carrier concentration, photon energy, and temperature, we give a short historical summary on how the concept of α evolved over the past two decades. This is followed by a discussion of α dependence on device structure in gain-guided and subdimensional lasers (quantum wells and quantum wires). The bulk of the paper is devoted to a detailed review of laser properties influenced by α and of associated methods of estimating the value of α. Results of measurements reported to date are collected and the most reliable methods are indicated.

Health Effects and Sources of Indoor Air Pollution. Part I

Abstract: Since the early 1970s, the health effects of indoor air pollution have been investigated with increasing intensity. Consequently, a large body of literature is now available on diverse aspects of indoor air pollution: sources, concentrations, health effects, engineering, and policy. This review begins with a review of the principal pollutants found in indoor environments and their sources. Subsequently, exposure to indoor air pollutants and health effects are considered, with an emphasis on those indoor air quality problems of greatest concern at present: passive exposure to tobacco smoke, nitrogen dioxide from gas-fueled cooking stoves, formaldehyde exposure, radon daughter exposure, and the diverse health problems encountered by workers in newer sealed office buildings. The review concludes by briefly addressing assessment of indoor air quality, control technology, research needs, and clinical implications.

Form, effect size and power in moderated regression analysis

Abstract: This paper presents the results of a simulation study designed to show how a moderator variable affects the form of the relationship between two other variables. Particular attention is paid to the relationship of the strength of a moderator to statistical significance and the magnitude of the increment in R2 associated with the moderator. The increment in R2 is viewed as an incomplete measure of the strength of moderator effects. We propose a standardized measure of the strength of moderator effects based on the rate of change in the slope of the regression surface. The relation of sample size and statistical power to this measure is investigated.

The accumulation of sexually antagonistic genes as a selective agent promoting the evolution of reduced recombination between primitive sex chromosomes.

Abstract: The evolution ofdimorphic sex chromosomes is generally thought to proceed in two stages: first a breakdown in recombination between the primitive X and Y chromosomes (Wand Z in a WZ system), followed by the loss of function of most Y-linked genes (for reviews, see Mittwoch [1967], Ohno [1979], and Bull [1983]). By primitive X and Y sex chromosomes, I mean homologous chromosomes that are differentiated only by the alleles (x or y; note that lower case symbols refer to genes, and upper case symbols refer to entire chromosomes) that they carry at a single sexdetermining locus. Fisher (1931) was the first to suggest that linkage to a sex-determining locus facilitates the accumulation of genes that are selectively favored in males (more generally, the heterogametic sex) but selected against in females. This idea was extended to the case of chromosomal translocations by Charlesworth and Charlesworth (1980). Close linkage to the y allele causes malebenefit/female-detriment genes to be transmitted more frequently to sons, where they are selectively favored. If such sexually antagonistic genes were to accumulate in linkage with a y allele, they would cross over onto the primitive X chromosome and reduce the average fitness of females. This crossover of male-benefit/female-detriment genes from yto x-linkage produces natural selection for both reduced recombination in the heterogametic sex and also sex-specific gene expression. Bull (1983, pp. 265-269) partially quantified Fisher's verbal model by considering two special cases: when the allele with sex-specific fitness is unlinked to the sex-determining locus, and when it is completely linked. He concluded that linkage between a sex-determining locus and a sexually antagonistic locus facilitates the maintenance of polymorphisms for alleles with opposing fitness effects in the two sexes. The work by Fisher (1931), Charlesworth and Charlesworth (1980), and Bull (1983) demonstrates that tight linkage between the sex locus and the sexually antagonistic locus facilitates the initial increase and maintenance ofy-linked male-benefit genes when they are detrimental to females. An important question that remains is how tight linkage must be in order to promote the accumulation (to substantial frequency) of male-benefit/female-detriment genes, especially when the disadvantage to females is high. That is, what are the "linkage constraints" (Charlesworth and Charlesworth, 1980) for the buildup of y-linked sexually antagonistic genes? The answer to this question is crucial, because the feasibility of breakdown in X-Y recombination via the accumulation of sexually antagonistic genes depends critically on the "genetic opportunity" for such genes to evolve. The looser the requisite linkage, the larger the pool ofgenetic variability that could be selected in a sex-specific manner, and the more feasible the model. Here, I address this question by solving for the equilibrium frequency of sexually antagonistic genes as a function of their recombinational distance from the sex locus. I conclude that very tight linkage is not required for the accumulation of genes that are lethal or semilethal to the homogametic sex.

Influences of eolian and pedogenic processes on the origin and evolution of desert pavements

Abstract: Well-developed desert pavements are present above eolian deposits that mantle flows of the Cima volcanic field, located in the Mojave Desert, California. Soil-stratigraphic data and geochemical data demonstrate that eolian and pedogenic processes play major roles in the evolution of these pavements. Eolian dust (1) accelerates mechanical fragmentation of flow rock, providing the source material for pavements, and (2) accumulates slowly below basaltic colluvium in flow depressions, eventually promoting development of cumulate soils below the evolving stone pavement. An increase in dust flux during the Holocene has raised ancient Pleistocene pavements as much as 20 cm above the former land surface. The results of our studies demonstrate for the first time that most desert pavements do not form by deflation, by overland flow, or by upward migration of stones through a slowly formed, clayey argillic horizon. Desert pavements are born and maintained at the surface.

Anglos and Mexicans in the Making of Texas, 1836-1986

Abstract: Acknowledgments 1. Introduction Part One. Incorporation, 1836-1900 2. The Rivalship of Peace 3. Cattle, Land, and Markets 4. Race, Labor, and the Frontier Part Two. Reconstruction, 1900-1920 5. The Coming of the Commercial Farmers 6. The Politics of Reconstruction Part Three. Segregation, 1920-1940 7. The Structure of the New Order 8. The Mexican Problem 9. The Web of Labor Controls 10. The Culture of Segregation 11. The Geography of Race and Class Part Four. Integration, 1940-1986 12. The Demise of "Jim Crow" 13. A Time of Inclusion Appendix. On Interpreting Southwestern History Notes Bibliography Index

Principal Components and Factor Analysis

Abstract: In Chapter 10 on correlation and regression we used an example of the numbers of runs scored in the 1975 and 1976 seasons by American League baseball clubs. The data were shown in Table 10–1 and the correlation was 0.63. Figure 17-1 shows the data plotted as a scatter diagram in standardized units.

The Effect of Proteoglycans on the Morphology of Collagen Fibrils Formed In Vitro

Abstract: The morphology of collagen fibrils at various times during formation in vitro was quantitatively examined by negative staining and by scanning electron microscopy. The presence of a small dermatan sulfate proteoglycan from bovine tendon (5 micrograms proteoglycan/100 micrograms collagen) resulted in collagen fibrils that were significantly thinner in width at all times by both methodologies. The rate of fibril diameter increase was also retarded by the small proteoglycans, suggesting that they inhibited the lateral aggregation of forming collagen fibrils. Large proteoglycans from cartilage did not produce this effect.

Genetic hitchhiking and the evolution of reduced genetic activity of the Y sex chromosome.

Abstract: A new model for the evolution of reduced genetic activity of the Y sex chromosome is described. The model is based on the process of genetic hitchhiking. It is shown that the Y chromosome can gradually lose its genetic activity due to the fixation of deleterious mutations that are linked with other beneficial genes. Fixation of deleterious Y -linked mutations generates locus-specific selection for dosage tolerance and/or compensation. The hitchhiking effect is most pronounced when operating in combination with an alternative model, Muller's ratchet. It is shown, however, that the genetic hitchhiking mechanism can operate under conditions where Muller's ratchet is ineffective.

Speciation via habitat specialization: the evolution of reproductive isolation as a correlated character

Abstract: A diverse group of theoretical and empirical studies are integrated into a composite model of sympatric speciation via habitat specialization. It is shown that disruptive selection on a continuous distribution of habitat preference can lead to the evolution of prezygotic reproductive isolation as a correlated character. The form of selection eliminates the major theoretical objections to the process of sympatric speciation. The principal difference between this model and the allopatric model of speciation is that the initial barrier to gene flow between subpopulations is produced by the evolution of gaps in the phenotypic distribution of spatial/temporal habitat use, rather than an extrinsic geographical barrier.

Factors influencing discrepancies between premortem and postmortem diagnoses.

Abstract: A study of 2067 autopsies collected from 32 university and community hospitals of various sizes located throughout the United States showed the rate of discrepancies between premortem and postmortem diagnoses to be influenced by the type and size of hospital, the age and sex of the patient, and the disease responsible for the patient's death. Of equivocal or no influence were the length of the terminal hospitalization, the degree of clinical involvement in the case of the person responsible for establishing the discrepancy level, and the autopsy rate, at least as it applies to community hospitals. (JAMA1987:258:339-344)

Fears, beliefs, and attitudes in DSM-III hypochondriasis.

Abstract: In order to explore fears, beliefs, and attitudes of patients with DSM-III hypochondriasis, the authors administered the self-rated Illness Attitude Scales to 21 patients with hypochondriasis, matched family practice patients, nonpatient employees, and nonhypochondriacal psychiatric patients. Hypochondriacal patients reported more fears of and false beliefs about disease; they attended more to bodily sensations, had more fears about death, and distrusted physicians' judgments more, yet sought more medical care than other subjects. They did not take better precautions about their health. The self-report of overt attitudes suggests a characteristic syndrome, consistent with the DSM-III description of hypochondriasis. Two of the subscales of the Illness Attitude Scales yielded characteristic responses in hypochondriasis.

Sedimentologic and geomorphic variations in storm-generated alluvial fans, Howgill Fells, northwest England

Abstract: In June 1982, a storm with a return period greater than 100 yr, but lasting less than 2.5 hr, destabilized hillslopes and produced a suite of geomorphologically and sedimentologically diverse alluvial fans. Thirteen major fans were deposited at the tributary junctions between small ( 2 ) catchments and two north-flowing; headwater streams of the River Lune, northwest England. Storm-generated fans spread over or became inset into older stable fans and produced localized vertical accretion of as much as 3 m and lateral accretion of as much as 100 m. Sedimentary processes operating during deposition involved debris flow, transitional flow, and streamflow. Six facies types are recognized on the basis of depositional topography, sedimentary texture and fabric, and matrix content: viscous debris flow (D1), dilute debris flow (D2), transitional flow (T1), fluvial bars and lobes (S1, S2), and fluvial sheet gravels (S3). Regionally, streamflow deposition prevails over debris-flow deposition, and type S3 facies has the greatest areal extent. Temporal and spatial variations in facies deposition during the storm, however, resulted from water:sediment ratio variations. Fan deposition involved an early phase of debris flow to transitional flow due to large inputs of sediment from hillslope failures. This was followed by a systematic change to more dilute conditions, resulting in streamflow deposition and eventually in channel incision. A significant amount of geomorphic work and complex variations in sedimentary processes during the storm resulted, in part, from extensive overland flow and hillslope destabilization. Discriminant analyses indicate that catchment size, channel gradient, and percentage of area eroded during the storm controlled whether debris-flow or streamflow facies dominated a fan sequence. Smaller, steeper catchments had a greater percentage of the area yielding sediment and are dominanted by debris flows, whereas larger catchments produced more runoff resulting in dilution and streamflow. The results indicate that the facies sequences and fan entrenchment in the Howgill Fells, which are typically considered products of longer term climatic change or tectonics in other localities, are here primarily affected by thresholds related to catchment geomorphology, by the type of sediment available, and by the position within the storm cell.

Proton-detected heteronuclear edited and correlated nuclear magnetic resonance and nuclear Overhauser effect in solution

Abstract: The proton has been the nucleus of choice for NMR studies of macromolecules because it is ubiquitous; it provides the highest sensitivity; its resonances can be identified with types of amino and nucleic acids by means of experiments utilizing proton spin-spin interaction and chemical shift; and, most important, proton NMR yields distance information via the nuclear Overhauser effect (NOE). Many of these advantages are lost for larger biopolymers (molecular weight more than 15 kDa) for which the line width is considerably greater than the proton-proton spin-spin interaction. The spin-spin interaction is then useless or difficult to use for assignment; and furthermore the proton line width and the number of proton resonances both increase in proportion to the molecular weight, thereby increasing the problem of resonance overlap to an intolerable degree.

Alpha-decay--induced fracturing in zircon: the transition from the crystalline to the metamict state.

Abstract: Zonation due to alpha-decay damage in a natural single crystal of zircon from Sri Lanka is discussed. The zones vary in thickness on a scale from one to hundreds of microns. The uranium and thorium concentrations vary from zone to zone such that the alpha decay dose is between 0.2 x 10 to the 16th and 0.8 x 10 to the 16th alpha-events per milligram. The transition from the crystalline to the aperiodic metamict state occurs over this dose range. At doses greater than 0.8 x 10 to the 16th alpha events/mg there is no evidence for long-range order. This type of damage will accumulate in actinide-bearing, ceramic nuclear waste forms. The systematic pattern of fractures would occur in crystalline phases that are zoned with respect to actinide radionuclides.

Dynamics of heterotrophic succession in carrion arthropod assemblages: discrete seres or a continuum of change?

Abstract: Patterns of species change, computed day to day community similarity, polar ordination, and other statistics were used to discern successional trends and correspondence with named decay stages from eleven carrion arthropod studies The carrion arthropod community develops primarily as a continuum of gradual change: rapid at first, slow during peak activity, and erratic in the final days as carcass resources become depleted In only five studies the ordination analysis revealed recognizable clusters representing discrete faunal seres; none of these, however, completely supported a stage-based view of faunal succession Collectively, the authors of published studies identified 29 decay stage boundaries; of these, only 14 were associated with major faunal changes We found at least 27 additional episodes involving compositional differences in the fauna not recorded by the authors Named decay stages may have descriptive utility in carrion studies However, ecologists and forensic entomologists should be alerted to the inadequacies of decay stages in summarizing patterns of faunal succession in carrion arthropod investigations

An Observation Scale for Measuring Children's Distress During Medical Procedures

Abstract: The current state-of-the-art in the area of assessing pain and anxiety experienced by children undergoing painful medical procedures remains at a rudimentary level. Early studies in the preparation literature included global Likert-type rating scales of children’s distress and cooperative behaviors (Visintainer & Wolfer, 1975; Wolfer & Visintainer, 1979). More recent studies have focused on the development of more objective and operationalized behavioral observation scales which have been used specifically to measure distress in pediatric cancer patients undergoing bone marrow aspirations (BMAs) and lumbar punctures (LPs) (Jay, in press; Jay & Elliott, 1984; Jay, Ozolins, Elliott, & Caldwell, 1983; Katz, Kellerman, & Siegel, 1980; LeBaron & Zeltzer, 1984). For example, Katz et al. (1980) developed the Procedure Behavior Rating Scale (PBRS) which consisted of 13 operationally defined behaviors that were recorded as present or absent during bone marrow aspirations. The PBRS was found to be a reliable instrument and preliminary validity data (i.e., nurse ratings) were also encouraging. LeBaron and Zeltzer (1984) presented additional validity data on an eight-item version of the PBRS which they labeled the Procedure Behavior Check List.

The relationship between growth, profitability, and firm value

Abstract: This research examined predictions drawn from value-based planning models. Results indicate that profitability and growth do influence shareholder value in the manner predicted; however, the relationships are conditional. This study also shows that, the market-to-book value of equity ratio and Tobin's q-ratio are theoretically and empirically, equivalent measures of value creation.

Thyroid failure in the elderly: microsomal antibodies as discriminant for therapy

Abstract: Thyrotropin (thyroid-stimulating hormone [TSH]) levels were elevated above 4.0 mU/L (μU/mL) in serum samples from 13.2% of 258 healthy elderly subjects. To investigate the natural history of progressive thyroid failure, serial thyroid functions were measured for four years in 26 of these subjects with elevated TSH levels. In one third of these subjects, biochemical thyroid failure developed (thyroxine level ( JAMA 1987;258:209-213)

Surgical clip and applier

Abstract: A surgical clip is disclosed having a pair of spaced arms joined by a bridge that is deformed by pulling on a tang, which is connected to the bridge by a frangible neck. Also disclosed is a tool for pulling the tang, and an anastomosis procedure that may be quickly performed using the clip and tool.

Prevalence of benign, atypical, and malignant breast lesions in populations at different risk for breast cancer. A forensic autopsy study.

Abstract: A forensic autopsy series of 519 women more than 14 years old was studied for prevalence of benign, atypical, and occult malignant breast lesions The women included Anglos (non-Hispanic whites), Hispanics, and American Indians from New Mexico and Eastern Arizona These three ethnic/racial groups are at markedly different risk for the development of breast cancer (Anglo 89 of 100,000) women per year, Hispanic 455, and American Indian 249 There were striking ethnic/racial and age-related differences in both the prevalence and magnitude of all forms of nonproliferative and proliferative fibrocystic disease The various subsets of fibrocystic disease were highly associated with each other Such lesions as apocrine metaplasia, sclerosing adenosis, and lobular microcalcification showed as much difference according to ethnic/racial background and age as the more common cystic change and duct epithelial hyperplasia Atypical lobular and ductal hyperplasia, carcinoma fit situ, and occult invasive carcinoma were uncommon and also occurred in ethnic/racial groups in a pattern that parallels the cancer risk in those groups

A NMR technique for the analysis of pore structure: Application to materials with well-defined pore structure

Abstract: The application of NMR spin—lattice relaxation measurements of water contained in porous solids is investigated as a possible tool for the determination of pore size distributions. NMR methods have several potential advantages over conventional porosimetry/adsorption techniques including the study of wet porous solids, a wide range of sample sizes that may be studied, and the fact that no pore shape assumption is required. In principle, water contained in a pore will relax faster than bulk water. This decrease in the observed relaxation rate decay constant, T1, is directly related to the pore volume to surface area ratio (i.e., hydraulic radius) according to the “two-fraction, fast-exchange model.” However, the suitability of this model and NMR spin—lattice relaxation measurements for the determination of pore size distributions has not been previously demonstrated. Pore size distributions have been determined for two series of porous solids by mercury porosimetry and a NMR method. A series of four controlled-pore glasses with very narrow pore size distributions and a mean radius in the range 3.4 to 17.6 nm were studied at a frequency of 20 MHz and at four temperatures. By using four samples with similar surface chemistry/ pore shape, the validity of the two-fraction, fast-exchange model was assessed. Experiments were conducted using a 180°–τ-90° pulse sequence and the distribution of T1 was calculated using a nonnegative leastsquares routine (NNLS) presented in a previous paper. The two-fraction model described the change of mean T1 with pore radius at a given temperature. The change of the surface relaxation decay constant, T1s, fit an Arrhenius expression with an activation energy of 1.8 kcal/mole. Agreement between the mercury porosimetry and NMR derived pore size distributions is excellent. T1 measurements at both 20 and 300 MHz and 303 K were also made on a series of porous solids fabricated by pelleting submicron silica spheres. These solids exhibit afairly wide pore size distribution (⋍ one order of magnitude). The two-fraction, fast-exchange model satisfactorily described the relationship between pore size and T1. Agreement between mercury porosimetry and NMR pore size distributions is good. However, the NMR derived distributions consisted of a series of narrow peaks overlapping the single broad porosimetry peak. The surface relaxation effect, and, hence, the overall pore size sensitivity, is increased by a factor of 3 when the proton frequency is decreased from 300 to 20 MHz.

Female aggression in cross-cultural perspective.

Abstract: This paper presents findings from a preliminary cross-cultural survey of adult human female aggression. Cases of female-initiated aggres sion, ranging from verbal abuse to murder, are found in all regions of the world. Female aggression is largely directed against other females and generally involves little injury. Co-wives and other rivals in sex and marriage are the most common victims. Husbands are the most common male targets. Female aggression is often a means of competing for men or subsistence products, but it may also be a means of defense.

Distribution of histopathology and Ia positive cells in actively induced and passively transferred experimental autoimmune orchitis.

Abstract: Histopathology in testes from mice with actively induced experimental orchitis (EAO) (active EAO) and those from recipients of testis-sensitized lymphocytes (passive EAO) had different distributions. In passive EAO, maximum orchitis existed in the straight tubules, rete testis, and ductus efferentes, obstruction of which led to extreme dilatation of seminiferous tubules. Unusual intralymphatic granulomata also resulted in dilated testicular lymphatics. In active EAO, maximum orchitis affected seminiferous tubules under the testicular capsule, away from the rete testes. Vasitis was common and occurred in both active and passive EAO. In normal testes, IA+ F4/80+ cells were sparse but formed a cuff around the straight tubules. After immunization with testis in adjuvant or with adjuvant alone, the number, size, and staining intensity of IA+ cells increased dramatically beginning on day 5, 7 days before disease onset. Simultaneously, epithelial cells confined to the ductus efferentes became Ia+. Although recipients of sensitized lymphocytes also developed epithelial Ia in the ductus efferentes, they did not show changes in testicular interstitial Ia+ cells. Our findings indicate that testicular autoantigens are not completely sequestered, but are accessible to and can react with passively transferred immune lymphocytes in well-defined regions of the germ cell compartment. These regions coincided to a large extent with maximum expression of periductal or epithelial Ia. Changes in Ia+ cells in the testis, which are inducible by adjuvants and precede orchitis, may account in part for the different distribution of histopathology of active EAO.

Response of Quaternary fluvial systems to differential epeirogenic uplift: Aguas and Feos river systems, southeast Spain

Abstract: The geomorphic expression of two fluvial systems, the Rio de Aguas and the Rambla de los Feos, in southeast Spain reflects their adjustment to differential epeirogenic uplift and local tectonic activity during the Quaternary. Regional uplift of a depositional marine surface resulted in the development of a southward-flowing drainage network during late Pliocene–early Pleistocene time. Disruption of this consequent drainage began as the Alhamilla-Cabrera Sierras and the Sorbas basin were differentially uplifted relative to the surrounding basins. The ancestral Feos drainage responded by incision across the uplift through a combination of superimposition and antecedence. Differential uplift of the Sorbas basin enhanced headward erosion of strike-oriented drainages and promoted capture of the ancestral Feos drainage by the Rio de Aguas during the late Pleistocene. Stratigraphic relations and soil development indicate that epeirogenic uplift and local tectonics, together with climatic fluctuations, have influenced the development of the drainage systems throughout the Quaternary.