Showing papers by "San Francisco State University published in 1998"

Improving Schooling for Language‐Minority Children: A Research Agenda.*

Abstract: How do we effectively teach children from homes in which a language other than English is spoken? In Improving Schooling for Language-Minority Children, a committee of experts focuses on this central question, striving toward the construction of a strong and credible knowledge base to inform the activities of those who educate children as well as those who fund and conduct research. The book reviews a broad range of studies--from basic ones on language, literacy, and learning to others in educational settings. The committee proposes a research agenda that responds to issues of policy and practice yet maintains scientific integrity. This comprehensive volume provides perspective on the history of bilingual education in the United States; summarizes relevant research on development of a second language, literacy, and content knowledge; reviews past evaluation studies; explores what we know about effective schools and classrooms for these children; examines research on the education of teachers of culturally and linguistically diverse students; critically reviews the system for the collection of education statistics as it relates to this student population; and recommends changes in the infrastructure that supports research on these students.

Symbolic and functional positioning of brands

Abstract: Some brand strategists have distinguished between symbolic and functional brands, i.e. brands that basically satisfy consumers’ functional or product‐related needs and brands bought to enhance self‐ or social esteem. It has been suggested that brands should be positioned as either functional or symbolic but not both. However, empirical research on the dimensionality of brand symbolism/functionality has been lacking. In this study, scales were developed to assess a brand’s symbolic or functional association with consumers. Subsequent data analysis suggests that brand symbolism and functionality are separate phenomena and, further, that symbolism comprises two dimensions, termed prestige and personality expression. Thus, contrary to current thinking, it seems that brands can be successfully positioned as both symbolic and functional and, if a symbolic brand concept is desired, prestige or upscaleness is just one of the possible positioning options available.

Impact of Strategic Alliances on Firm Valuation

Abstract: This study analyzed 119 strategic alliances formed during the period 1987–91. Using the event study methodology, we found that announcements of technological alliances enjoyed greater abnormal retu...

Silicate regulation of new production in the equatorial Pacific upwelling

Abstract: Surface waters of the eastern equatorial Pacific Ocean present the enigma of apparently high plant-nutrient concentrations but low phytoplankton biomass and productivity1. One explanation for this ‘high-nitrate, low-chlorophyll’ (HNLC) phenomenon has been that growth is limited by iron availability2,3. Here we use field data and a simple silicon-cycle model4 to investigate the HNLC condition for the upwelling zone of this ocean region. Measured silicate concentrations in surface waters are low and largely invariant with time, and set the upper limit on the total possible biological utilization of dissolved inorganic carbon. Chemical and biological data from surface waters indicate that diatoms—silica-shelled phytoplankton—carry out all the ‘new production’ (nitrate uptake)5. Smaller phytoplankton (picoplankton) accomplish most of the total primary production, largely fuelled by nitrogen regenerated in reduced forms as a result of grazing by zooplankton. The model predicts values of new and export production (the production exported to below the euphotic zone) that compare well with measured values6. New and export production are in balance for biogenic silica, whereas new production exceeds export for nitrogen. The HNLC condition in the upwelling zone can therefore be understood to be due to a chemostat-like regulation of nitrate uptake by upwelled silicate supply to diatoms: ‘low-silicate HNLC’. These results are not inconsistent with observations of iron-fertilized diatom growth during in situ experiments in ‘low-iron HNLC’ waters outside this upwelling zone2,3, but reflect the role of different supply rates of iron and silicate in determining the nature of the HNLC condition.

Ecology and speciation

Abstract: Recent studies on diverse taxa suggest that natural selection caused by shifts in ecology or invasions of novel habitats plays an important role in adaptive divergence and speciation. Exciting new studies integrating approaches from both the field and the laboratory suggest that ecological shifts can result in extremely rapid rates of evolutionary divergence. Although experimental approaches that link rapid ecological divergence to reproductive isolation and speciation are in their infancy, recent research indicates those approaches that will be most useful.

Xa21D Encodes a Receptor-like Molecule with a Leucine-Rich Repeat Domain That Determines Race-Specific Recognition and Is Subject to Adaptive Evolution

Abstract: The rice Xa21 gene confers resistance to Xanthomonas oryzae pv oryzae in a race-specific manner. Analysis of the inheritance patterns and resistance spectra of transgenic plants carrying six Xa21 gene family members indicated that one member, designated Xa21D , displayed a resistance spectrum identical to that observed for Xa21 but conferred only partial resistance. Xa21D encodes a receptor-like protein carrying leucine-rich repeat (LRR) motifs in the presumed extracellular domain. The Xa21D transcript terminates shortly after the stop codon introduced by the retrotransposon Retrofit . Comparison of nucleotide substitutions in the LRR coding regions of Xa21 and Xa21D provided evidence of adaptive selection. Both functional and evolutionary evidence indicates that the Xa21D LRR domain controls race-specific pathogen recognition.

Magnetic Activity-related Radial Velocity Variations in Cool Stars: First Results from the Lick Extrasolar Planet Survey

Abstract: The discovery of the radial velocity (v -->r) signatures of planets around several solar-like stars highlights the importance of exploring the sources of v -->r variations intrinsic to the stars themselves. We study the stars in the Lick planetary survey for v -->r variations related to stellar activity: the rotation of starspots and convective inhomogeneities and their temporal evolution. We study the relationships between the weighted v -->r dispersion, ?'v (which has first been corrected for the orbital contribution from known planets and the mean internal error), and spectral type, rotation, and activity (as measured by Ca II H and K). We find that the largest ?'v values occur among both the coolest (dMe) and the warmest (active F) stars. Values of ?'v increase with H and K emission and scale proportional to vsin${r sin}$ -->${r sin}$ -->i in G and K stars and proportional to (vsin${r sin}$ -->${r sin}$ -->i) -->1.3 in F stars. For a G star with vsin${r sin}$ -->${r sin}$ -->i ? 8-10 km s -->?1 (age ~0.3 Gyr), for example, 20 m s -->?1 ?'v 45 m s -->?1, roughly consistent with the predicted ?'v levels due to magnetic activity (Saar & Donahue). All the stars with proposed planetary companions show ?'v values typical for their spectral type, activity, and/or rotation. However, before the planetary v -->r perturbations are removed, these stars show significantly enhanced ?'v values. We develop a simple model that can predict the ?'v expected for a given star (within ? 40%) as a function of vsin${r sin}$ -->${r sin}$ -->i, spectral type, photometric variability, and macroturbulent velocity. The implications for extrasolar planet searches are discussed.

Protection against peroxynitrite-induced fibroblast injury and arthritis development by inhibition of poly(ADP-ribose) synthase.

Abstract: Peroxynitrite, a cytotoxic oxidant formed from nitric oxide (NO) and superoxide, induces DNA strand breakage, which activates the nuclear enzyme poly(ADP-ribose) synthase (PARS; EC 2.4.2.30). The cellular function of PARS was determined in fibroblast lines from PARS knockout animals (PARS−/−) and corresponding wild-type animals (PARS+/+), with the aid of the lipophilic PARS inhibitor 5-iodo-6-amino-1,2-benzopyrone (INH2BP). We investigated the role of PARS in peroxynitrite-induced fibroblast injury in vitro and also in the development of arthritis in vivo. Exposure of embryonic fibroblasts from the PARS+/+ animals to peroxynitrite caused DNA single-stand breakage and PARS activation and caused an acute suppression of mitochondrial respiration. INH2BP protected the PARS+/+ cells against the suppression of mitochondrial respiration in response to peroxynitrite (50–100 μM). Similarly to PARS inhibition with INH2BP, the PARS−/− cells were protected against peroxynitrite-induced injury. The protection against cellular injury by PARS−/− phenotype or INH2BP waned when cells were challenged with higher concentrations of the oxidant. Inhibition of PARS by INH2BP or by PARS−/− phenotype reduced inducible nitric-oxide synthase (iNOS; EC 1.14.13.39) mRNA levels and inhibited production of NO in immunostimulated cells. INH2BP had no peroxynitrite scavenging or hydroxyl radical scavenging effects, and it exerted no additional (nonspecific) effects in the PARS−/− cells. In collagen-induced arthritis, significant staining for nitrotyrosine, a marker of peroxynitrite formation, was found in the inflamed joints. Oral treatment with INH2BP (0.5 g/kg, daily), starting at the onset of arthritis (day 25), delayed the development of the clinical signs at days 26–35 and improved histological status in the knee and paw. Our data demonstrate that deletion of PARS by genetic manipulation or pharmacological inhibition of PARS protects against oxidant-induced cellular injury in vitro and exhibits anti-inflammatory effects in vivo.

The contribution of individualism vs. collectivism to cross-national differences in display rules*

Abstract: Despite the fact that display rules are an important concept of theories of emotion and contemporary psychology, relatively little cross-cultural research has been done on them. This study examined cross-national differences in display rules of emotion, and investigated the degree to which those differences could be attributed to Individualism and Collectivism (IC) measured on the individual level. Participants in the US, Japan, South Korea, and Russia completed a comprehensive measure of display rules assessing behavioral tendencies for seven universal emotions in four social contexts in two rating domains. They also completed Matsumoto et al.’s (1997) Individualism–Collectivism Interpersonal Assessment Inventory. The results confirmed the existence of cross-national differences in IC and display rules, and indicated that IC and display rules were correlated. Significant differences between the countries remained even after IC was controlled for, and effect size analyses comparing cross-national differences when IC was controlled and not indicated that IC accounted for approximately 30% of the effect sizes related to cross-national differences. This study is unique in that it not only used the concept of IC to explain and predict differences; it also quantitatively assessed the degree to which IC contributed to those differences. These findings are discussed in terms of the utility of the IC concept to understanding cross-cultural and cross-national differences in emotion.

Tidally oriented vertical migration and position maintenance of zooplankton in a temperate estuary

Abstract: In many estuaries, maxima in turbidity and abundance of several common species of zooplankton occur in the low salinity zone (LSZ) in the range of 0.5–6 practical salinity units (psu). Analysis of zooplankton abundance from monitoring in 1972–1987 revealed that historical maxima in abundance of the copepod Eurytemora affinis and the mysid Neomysis mercedis, and in turbidity as determined from Secchi disk data, were close to the estimated position of 2 psu bottom salinity. The copepod Sinocalanus doerrii had a maximum slightly landward of that of E. affinis. After 1987 these maxima decreased and shifted to a lower salinity, presumably because of the effects of grazing by the introduced clam Potamocorbula amurensis. At the same time, the copepod Pseudodiaptomus forbesi, the mysid Acanthomysis sp., and amphipods became abundant with peaks at salinity around 0.2–0.5 psu.

WFPC2 Observations of Star Clusters in the Magellanic Clouds. II. The Oldest Star Clusters in the Small Magellanic Cloud

Abstract: We present our analysis of archival Hubble Space Telescope Wide Field Planetary Camera 2 (WFPC2) observations in F450W (~B) and F555W (~V) of the intermediate-age populous star clusters NGC 121, NGC 339, NGC 361, NGC 416, and Kron 3 in the Small Magellanic Cloud. We use published photometry of two other SMC populous star clusters, Lindsay 1 and Lindsay 113, to investigate the age sequence of these seven star clusters in order to improve our understanding of the formation chronology of the SMC. We analyzed the V versus B-V and MV versus (B-V)0 color-magnitude diagrams of these populous Small Magellanic Cloud star clusters using a variety of techniques and determined their ages, metallicities, and reddenings. These new data enable us to improve the age-metallicity relation of star clusters in the Small Magellanic Cloud. In particular, we find that a closed-box continuous star formation model does not reproduce the age-metallicity relation adequately. However, a theoretical model punctuated by bursts of star formation is in better agreement with the observational data presented herein.

Genetic Variation and Phylogeography of Central Asian and Other House Mice, Including a Major New Mitochondrial Lineage in Yemen

Abstract: The mitochondrial DNA (mtDNA) control region and flanking tRNAs were sequenced from 76 mice collected at 60 localities extending from Egypt through Turkey, Yemen, Iran, Afghanistan, Pakistan, and Nepal to eastern Asia. Segments of the Y chromosome and of a processed p53 pseudogene (Psip53) were amplified from many of these mice and from others collected elsewhere in Eurasia and North Africa. The 251 mtDNA types, including 54 new ones reported here, now identified from commensal house mice (Mus musculus group) by sequencing this segment can be organized into four major lineages-domesticus, musculus, castaneus, and a new lineage found in Yemen. Evolutionary tree analysis suggested the domesticus mtDNAs as the sister group to the other three commensal mtDNA lineages and the Yemeni mtDNAs as the next oldest lineage. Using this tree and the phylogeographic approach, we derived a new model for the origin and radiation of commensal house mice whose main features are an origin in west-central Asia (within the present-day range of M. domesticus) and the sequential spreading of mice first to the southern Arabian Peninsula, thence eastward and northward into south-central Asia, and later from south-central Asia to north-central Asia (and thence into most of northern Eurasia) and to southeastern Asia. Y chromosomes with and without an 18-bp deletion in the Zfy-2 gene were detected among mice from Iran and Afghanistan, while only undeleted Ys were found in Turkey, Yemen, Pakistan, and Nepal. Polymorphism for the presence of a Psip53 was observed in Georgia, Iran, Turkmenistan, Afghanistan, and Pakistan. Sequencing of a 128-bp Psip53 segment from 79 commensal mice revealed 12 variable sites and implicated >/=14 alleles. The allele that appeared to be phylogenetically ancestral was widespread, and the greatest diversity was observed in Turkey, Afghanistan, Pakistan, and Nepal. Two mice provided evidence for a second Psip53 locus in some commensal populations.

Phylogenetic relationships among the pine stem rust fungi (Cronartium and Peridermium spp.)

Abstract: Species in Cronartium and its anamorphic genus Peridermium form a morphologically homoge- neous group of rust fungi that infect stems, branches, and cones of Pinus species in North and Central America, Asia, and Europe. Several species are im- portant forest pathogens, causing severe economic and aesthetic damage to pines in forests and parks throughout the northern hemisphere. Morphologi- cal characters have been used to distinguish among these rust fungi, but have proven inadequate for as- sessing phylogenetic relationships within the group. In this study, we extracted fungal DNA from spores

Seed dispersal by Ceratogymna hornbills in the Dja Reserve, Cameroon

Abstract: Seed dispersal is a process critical to the maintenance of tropical forests, yet little is known about the interactions of most dispersers with their communities. In the Dja Reserve, Cameroon, seed dispersal by the hornbills Cerato- gymna atrata, C. cylindricus and C. fistulator (Aves: Bucerotidae) was evaluated with respect to the taxonomic breadth of plants dispersed, location of seed deposition and effects on seed germination. Collectively, the three hornbill species consumed fruits from 59 tree and liana species, and likely provided dispersal for 56 of them. Hornbill-dispersed tree species composed 22% of the known tree flora of the site. Hornbill visit lengths, visit frequencies, and seed passage times indicated that few seeds were deposited beneath parent trees; in five hornbill/tree species pairings studied, 69-100% of the seeds ingested were deposited away from the parent trees. Germination trials showed that hornbill gut passage is gentle on seeds. Of 24 tree species tested, 23 germinated after passage by hornbills; of 17 planted with con- trols taken directly from trees, only four species showed evidence of inhibition of germination rate, while seven experienced unchanged germination rates and six experienced enhanced germination rates. Results suggested that Ceratogymna horn- bills rank among the most important seed dispersers found in Afrotropical forests, and they deserve increased conservation attention. Ceratogymna hornbills are likely to become increasingly important in forest regeneration as populations of larger mammalian seed dispersers (such as forest elephants and primates) diminish.

The Luminosity Function of the Globular Cluster NGC 6397 near the Limit of Hydrogen Burning

Abstract: Second-epoch Hubble Space Telescope observations of NGC 6397 have led to the measurement of proper motions accurate enough to separate the faintest cluster stars from the field, thus extending the luminosity function of this globular cluster far enough to approach the limit of hydrogen burning on the main sequence. We isolate a sample of 1385 main-sequence stars, from just below the turnoff down to I = 24.5 (MI 12.5), which corresponds to a mass of less than 0.1 m☉ for the metallicity of this cluster. Below I = 22 (MI 10), the main-sequence luminosity function drops rapidly, in a manner similar to that predicted by theoretical models of low-mass stars near the hydrogen-burning limit.

Preschool language and metalinguistic skills are links to reading success

Abstract: This article reports the longitudinal follow-up of 41 preschool children as they moved into reading. When the children were 3 years old, they participated in a detailed assessment of their language, print, and metalinguistic skills. At the end of first grade, the children received two tests of phonological awareness and three reading measures: sound–symbol knowledge, word identification, and passage comprehension. Overall language development at age 3 just as strongly, or even more strongly, correlated with reading scores at age 7 as it had with metalinguistic and print awareness scores at age 3. In addition, the overall metalinguistic skills and print awareness of 3 year olds made significant contributions to reading achievement beyond what was provided by tacit language development. Specific metalinguistic domains were also good predictors of reading, with phonological and structural awareness offering more than word awareness.

A 5.8S nuclear ribosomal RNA gene sequence database: applications to ecology and evolution

Abstract: We complied a 5.8S nuclear ribosomal gene sequence database for animals, plants, and fungi using both newly generated and GenBank sequences. We demonstrate the utility of this database as an internal check to determine whether the target organism and not a contaminant has been sequenced, as a diagnostic tool for ecologists and evolutionary biologists to determine the placement of asexual fungi within larger taxonomic groups, and as a tool to help identify fungi that form ectomycorrhizae.

Minimally Invasive Detection of Piscirickettsia salmonis in Cultivated Salmonids via the PCR

Abstract: The attributes of the PCR allowed implementation of an assay for specific detection of Piscirickettsia salmonis from a few microliters of fish serum. This opens the way to less invasive modes of sampling for this microbial pathogen in salmonids.

WIYN Open Cluster Study. I. Deep Photometry of NGC 188

Abstract: We have employed precise and carefully calibrated V- and I-band photometry of NGC 188 at WIYN Observatory to explore the cluster luminosity function (LF) and study the cluster white dwarfs. Our photometry is offset by V = 0.052 (fainter) from that of Sandage and Eggen & Sandage. All published photometry for the past three decades has been based on these two calibrations, which are in error by 0.05 ± 0.01. We employ the Pinsonneault et al. fiducial open cluster main sequence to derive a distance modulus of 11.43 ± 0.08 and E(B-V) = 0.09, with the largest single source of error caused by uncertainty in the cluster metallicity. We report observations that are ≥50% complete along the main sequence to V = 24.6. We find that the NGC 188 central-field LF peaks at MI ≈ 3 to 4. This is unlike the solar neighborhood LF and unlike the LFs of dynamically unevolved portions of open and globular clusters, all of which typically rise continuously until MI ≈ 9.5. Although we find that ≥50% of the unresolved objects in this cluster are multiple systems with mass ratios ≥0.3, their presence cannot account for the shape of the NGC 188 LF. For theoretical reasons having to do with the long-term survivability of NGC 188, we believe the cluster is highly dynamically evolved and that the low-luminosity stars missing from the central cluster LF are either in the cluster outskirts or have left the cluster altogether. We identify nine candidate white dwarfs (WDs) in NGC 188, of which we expect at least three, and perhaps six, are bona fide cluster WDs. The luminosities of the faintest likely WD indicate an age of 1.14 ± 0.09 Gyr, where the error in age includes the cluster distance uncertainty and we assume the WD has a hydrogen atmosphere. This age is a lower limit to the cluster age, and observations probing to V = 27 or 28 will be necessary to find the faintest cluster WDs and independently determine the cluster age. While our lower age limit is not surprising for this ≈6 Gyr–old cluster, our result demonstrates the value of the WD age technique with its very low internal errors.

Pseudoframes for subspaces with applications

Abstract: We define and characterize a frame-like stable decomposition for subspaces in a separable Hilbert space. We call in pseudoframes for subspaces (PFFS). Properties of PFFS are discussed. A necessary and sufficient condition for the construction is provided. An analytical formula for the construction of PFFS is also derived. An example is studied both as a motivation of the theoretical study of such pseudoframes and as an actual construction. Potential applications of PFFS are discussed.

Cataclysmic Variables and a New Class of Faint Ultraviolet Stars in the Globular Cluster NGC 6397

Abstract: We present evidence that the globular cluster NGC 6397 contains two distinct classes of centrally concentrated UV-bright stars. Color-magnitude diagrams constructed from U -->336, B -->439, V -->555, and I -->814 data obtained with the Hubble Space Telescope Wide Field Planetary Camera 2 reveal seven UV-bright stars fainter than the main-sequence turnoff, three of which had previously been identified as cataclysmic variables (CVs). Light curves of these stars show the characteristic flicker of CVs as well as longer term variability. A fourth star is identified as a CV candidate on the basis of its variability and UV excess. Three additional UV-bright stars show no photometric variability and have broadband colors characteristic of B stars. These nonflickering UV stars are too faint to be extended horizontal-branch stars. We suggest that they could be low-mass helium white dwarfs, formed when the evolution of a red giant is interrupted, due either to Roche lobe overflow onto a binary companion or to envelope ejection following a common-envelope phase in a tidal-capture binary. Alternatively, they could be very low mass core-He-burning stars. Both the CVs and the new class of faint UV stars are strongly concentrated toward the cluster center, to the extent that mass segregation from two-body relaxation alone may be unable to explain their distribution.

Lifestyles of Students with Visual Impairments: Preliminary Studies of Social Networks

Abstract: In this investigation, we examined how adolescents and young adults (15- to 21-year-olds) with visual impairments spent their time engaged in academic, social, daily living, and vocational pursuits in comparison to youth without visual impairments. We conducted two studies: (a) a quantitative analysis between matched pairs of visually impaired and sighted adolescents, and (b) a qualitative analysis involving students with visual impairments only. Both studies identified socialization and career development as areas where students with visual impairments may need additional supports to achieve life success.

Dissipative enterprises, chaos, and the principles of lean organizations

Abstract: This paper proposes that `lean' organizations, which many observers believe constitute an entirely new `paradigm' of management and organization, are successful because their fundamental structure embodies many of the characteristics of `self-organizing' dynamic systems, such as `dissipative structures', which balance `chaos' with `order'. It employs concepts from modern information theory, cybernetics, and the comparatively new field of self-organizing systems. These concepts suggest that lean organizations are extremely flexible and highly adaptable to rapidly changing competitive conditions, and are characterized by continual reorganization, rapid new product development, and constant search for increased efficiency, all of which are the results of self-organizational processes.