Quadratic operator equations and periodic operator continued fractions

AbstractConditions are given that assure convergence of an operator-valued periodic continued fraction of period two. These results and techniques are applied to get a solution of the quadratic operator equation in a complex Hilbert space. Special attention is then given to the important case of the quadratic matrix equation connected with the steady-state solution of the matrix Riccati equation from control theory. It is shown that a modification of the traditional matrix power approximation technique leads to a new, efficient and highly simplified method of approximating the unique nonnegative definite solution that exists in many important special cases

Madrid: Literary Fiction and the Imaginary Urban Destination

This study selects novels from French and Spanish language traditions, which may not be available to English-speakers, in order to determine if specific aspects throw light on our understanding of Madrid as a destination. Marc Lambron's L'Impromptu de Madrid and Antonio Munoz Molina’s Mysteries of Madrid are taken as proof of the influence the narrative can exert on social daily life and consumption. Narrative foregrounds the fictions which are at stake in imagining the city as destination and also provides a vehicle for presenting the much broader social forces that converge in the author at the time of imagining and writing

Early Mesozoic Paleotectonic-Paleogeographic Reconstruction of Southern Sierra Nevada Region

A paleotectonic-paleogeographic reconstruction was based on structural, petrologic, and geochronologic studies of pre-Sierra Nevada batholith framework rocks exposed between the San Joaquin River and the Garlock fault. Most available fossil data from roof pendants of this region indicate Late Triassic to Early Jurassic ages. An additional fossil locality from the western wall rocks yields a Late Permian Tethyan fauna. This is a maximum age for the enclosing rocks, for the fossils are in a limestone olistolith. As yet there is no sign of Paleozoic strata in the region except perhaps along the eastern Sierran crest in small metamorphic septa, and in the western foothills where ophiolitic rocks are present

A Defendant\u27s Testimony, Which Is Expounded on Direct Examination or Elicited on Cross-Examination, May Be Rebutted by the Prosecution\u27s Introduction of Evidence, Obtained in Violation of Gideon, for the Purpose of Impeaching the Defendant\u27s Credibility, Regardless of Whether Such Evidence Pertains to a Collateral Matter or Is Directly Related to the Crime in Question.

Abstract Forthcoming

Elementary School Size and Differences in Student Progess: A Texas Statewide, Multiyear Investigation

The purpose of this journal-ready dissertation was to determine the degree to which student enrollment (i.e., school size) at elementary schools was related to student progress on the Texas state-mandated assessments for reading and for mathematics. In the first journal article, the effect of school size on student progress was examined for White, Hispanic, and Black students. In the second study, the extent to which school size was related to the student progress of students who were economically disadvantaged and of students who were at risk was ascertained. In the third investigation, the relationship between school size and student progress for boys and for girls was examined. In each of the three studies, five years of Texas statewide data were examined to ascertain the degree to which trends were present in student progress in reading and in mathematics as a function of their ethnicity/race, economic status, at risk status, and gender. Method For this study, a causal-comparative research design was present. Archival data from the Texas Academic Performance Report for the 2013-2014, 2014-2015, 2015-2016, 2016-2017, and 2017-2018 school years were analyzed. The independent variable was school size: Small-size (i.e., 50-399 students), Moderate-size (i.e., 400-799 students), and Large-size (i.e., 800 or greater students). Dependent variables were the reading progress measures and the mathematics progress measures on the STAAR Reading and Mathematics assessments analyzed separately by ethnicity/race, economic status, at risk status, and gender. Of the 35 statistical analyses conducted on the reading progress measures, 15 analyses had statistically significant differences in which reading progress rates were higher at Large-size schools; three analyses yielded better reading progress rates at Small-size schools; and 17 analyses did not reveal statistically significant results. Of the 28 statistical analyses on mathematics progress rates, 6 had statistically significant results in which mathematics progress rates were higher at Large-size schools; 8 analyses yielded higher mathematics progress rates at Small-size schools; and 14 analyses did not reveal statistically significant differences. Findings were inconsistent across ethnic/racial groups, economic status, at-risk status, and gender

Spawning, egg development, and early life history dynamics of arrowtooth flounder (Atheresthes stomias) in the Gulf of Alaska

Arrowtooth flounder (Atheresthes stomias) has the highest biomass of any groundfish species in the Gulf of Alaska, is a voracious predator of age 1 walleye pollock (Theragra chalcogramma), and is a major component in the diet of Steller sea lions (Eumetopias jubatus). Owing to its ecological importance in the Gulf of Alaska and the limited information available on its reproduction, interest has intensified in describing its spawning and early life history. A study was undertaken in late January–February 2001–2003 in the Gulf of Alaska to obtain information on adult spawning location, depth distribution, and sexual maturity, and to obtain fertilized eggs for laboratory studies. Adults were found 200–600 m deep east of Kodiak Island over the outer continental shelf and upper slope, and southwest along the shelf break to the Shumagin Islands. Most ripe females (oocytes extruded with light pressure) were found at 400 m and most ripe males (milt extruded with light pressure) were found at depths ≥450 m. Eggs were fertilized and incubated in the laboratory at 3.0°, 4.5°, and 6.0°C. Eggs were reared to hatching, but larvae did not survive long enough to complete yolk absorption and develop pigment. Eggs were staged according to morphological hallmarks and incubation data were used to produce a stage duration table and a regression model to estimate egg age based on water temperature and developmental stage. Arrowtooth flounder eggs (1.58–1.98 mm in diameter) were collected in ichthyoplankton surveys along the continental shelf edge, primarily at depths ≥400 m. Early-stage eggs were found in tows that sampled to depths of ≥450 m. Larvae, which hatch between 3.9 and 4.8 mm standard length, increased in abundance with depth. Observations on arrowtooth flounder eggs and early-stage larvae were used to complete the description of the published partial developmental series.(PDF file contains 34 pages.

Hemoglobin genotype has minimal influence on the physiological response of juvenile atlantic cod (Gadus morhua) to environmental challenges

Hemoglobin (Hb) polymorphism in cod is associated with temperature‐related differences in biogeographical distribution, and several authors have suggested that functional characteristics of the various hemoglobin isoforms (HbIs) directly influence phenotypic traits such as growth rate. However, no study has directly examined whether Hb genotype translates into physiological differences at the whole animal level. Thus, we generated a family of juvenile Atlantic cod consisting of all three main Hb genotypes (HbI‐1/1, HbI‐2/2, and HbI‐1/2) by crossing a single pair of heterozygous parents, and we compared their metabolic and cortisol responses to an acute thermal challenge (10&deg;C to their critical thermal maximum [CTM] or 22&deg;C, respectively) and tolerance of graded hypoxia. There were no differences in routine metabolism (at 10&deg;C), maximum metabolic rate, metabolic scope, CTM (overall mean 22.9&deg; &plusmn; 0.2&deg;C), or resting and poststress plasma cortisol levels among Hb genotypes. Further, although the HbI‐1/1 fish grew more (by 15%&ndash;30% during the first 9 mo) when reared at 10&deg; &plusmn; 1&deg;C and had a slightly enhanced hypoxia tolerance at 10&deg;C (e.g., the critical O2 levels for HbI‐1/1, HbI‐2/2, and HbI‐1/2 cod were 35.56% &plusmn; 1.24%, and 40.20% &plusmn; 1.99% air saturation, respectively), these results are contradictory to expectations based on HbI functional properties. Thus, our findings (1) do not support previous assumptions that growth rate differences among cod Hb genotypes result from a more efficient use of the oxygen supply&mdash;that is, reduced standard metabolic rates and/or increased metabolic capacity&mdash;and (2) suggest that in juvenile cod, there is no selective advantage to having a particular Hb genotype with regards to the capacity to withstand ecologically relevant environmental challenges.<br /

Guide to the identification of larval and early juvenile pricklebacks (Perciformes: Zoarcoidei: Stichaeidae) in the northeastern Pacific Ocean and Bering Sea

Stichaeidae, commonly referred to as pricklebacks, are intertidal and subtidal fishes primarily of the North Pacific Ocean. Broad distribution in relatively inaccessible and undersampled habitats has contributed to a general lack of information about this family. In this study, descriptions of early life history stages are presented for 25 species representing 18 genera of stichaeid fishes from the northeastern Pacific Ocean, Bering Sea, and Arctic Ocean Basin. Six of these species also occur in the North Atlantic Ocean. Larval stages of 16 species are described for the first time. Additional information or illustrations intended to augment previous descriptions are provided for nine species. For most taxa, we present adult and larval distributions, descriptions of morphometric, meristic, and pigmentation characters, and species comparisons, and we provide illustrations for preflexion through postflexion or transformation stages. New counts of meristic features are reported for several species