Showing papers by "University of Hawaii at Manoa published in 1985"

Group Work, Interlanguage Talk,and Second Language Acquisition.

Abstract: The use of group work in classroom second language learning has long been supported by sound pedagogical arguments. Recently, however, a psycholinguistic rationale for group work has emerged from second language acquisition research on conversation between non-native speakers, or interlanguage talk. Provided careful attention is paid to the structure of tasks students work on together, the negotiation work possible in group activity makes it an attractive alternative to the teacher-led, “lockstep” mode and a viable classroom substitute for individual conversations with native speakers.

Further segregation analysis of the fragile X syndrome with special reference to transmitting males

Abstract: A new series of 96 pedigrees with the fra(X) syndrome was analysed using complex segregation analysis with pointers, defining affection as any degree of mental impairment. These families were found to exhibit the same segregation pattern as the first series of 110 pedigrees (Sherman et al. 1984). The best estimate for penetrance of mental impairment in males was 79% and in females was 35% for the combined data. Again, there was little evidence for sporadic cases among affected males. Many more intellectually normal transmitting males have been observed since the existence of such males and the concomitant need to investigate the paternal side of pedigrees was recognized. On further investigation of all 206 pedigrees from the old and new data sets, the sibships of nonexpressing males appeared to be different from those of expressing males. Our analysis, using mental impairment as the phenotype, suggested that obligate carrier mothers and daughters of intellectually normal transmitting males are rarely, if ever, mentally impaired and that the sibs of transmitting males are much less likely to be retarded than the sibs of mentally impaired males. Though mothers and daughters of transmitting males are similar in phenotype, the expression of the gene in their offspring appears to be different: the penetrance of mental impairment is higher in offspring of intellectually normal daughters of transmitting males than in offspring of intellectually normal mothers of transmitting males. The implications of these observations for genetic counseling and for genetic models of the fra(X) syndrome are discussed.

Development of the ALOHANET

Abstract: The development of the ALOHA system packet broadcasting network at the University of Hawaii illustrates a number of general principles about the relationship between information theory and the design of real information systems. An anecdotal account is given of the development of the ALOHA system, emphasizing the interaction of the theory and the design of the experimental network. In addition, some preliminary results are described on the comparison of ALOHA channels and spread spectrum channels when used for packet communications.

Band mixing in semiconductor superlattices.

Abstract: Much understanding of the electronic and optical properties of a semiconductor superlattice can be obtained by relating the superlattice electronic wave functions and band structure to those of the two bulk semiconductors from which it is constructed. In this paper, the relationship is studied within the framework of the empirical tight-binding model, which is solved using the reduced Hamiltonian technique. The superlattice wave functions are described as linear combinations of bulk Bloch functions with complex wave vectors, twenty (including spin) for each of the two constituent materials. The bulk Bloch-function composition of the superlattice wave function is studied as a function of layer thickness, alloy composition, and energy. The GaAs-${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Al}}_{\mathrm{x}}$As and InAs-GaSb superlattices are examined in detail. Comparisons with simpler Kronig-Penney and envelope-function models are made. It is found that the lowest superlattice conduction-band states are primarily derived from the expected bulk states with wave vectors near the center of the Brillouin zone, with a small admixture of zone-edge components. The energies and general form of the wave functions are modified only slightly, except close to the interfaces. There, the admixture can significantly affect the interfacial boundary conditions beyond those employed by commonly used envelope-function approximations. Valence-band states are more complicated in that the superlattice periodic potential mixes the bulk heavy-hole, light-hole, and spin-orbit split-off bands, even at the superlattice Brillouin-zone center. Crossover effects occur in which a given superlattice subband can have a varying proportion of light-hole-like or heavy-hole-like character depending on superlattice layer thickness. The dispersion of the subbands away from the zone center also causes the mixing of bands and results in modifications of the superlattice band structure as compared with band structures produced by simpler models.

Intake: On Models and Methods for Discovering Learners' Processing of Input

Abstract: Models of the second language acquisition process have not specifically elaborated on the nature of the learner's perception and processing of target language input, a process known as intake. They have typically failed to specify the mechanisms or variables involved in the intake process or to distinguish between the stages of processing input from perception, to comprehension, to assimilation into an interlanguage grammar. Research and theoretical models from L1 psycholinguistic literature have been neglected. Recent L1 and L2 research on language processing are compared, and experimental methods for eliciting data to confirm them are discussed.

Effects of white blood cells on the in vitro penetration of zona-free hamster eggs by human spermatozoa.

Abstract: The presence of white blood cells in semen has been associated with male infertility. Previous studies indicate that pyospermia occurs in conjunction with decreases in sperm motility, number of normal sperm forms, and penetration rates in the zona-free hamster egg sperm penetration assay. We have evaluated the relationship of seminal white blood cells and sperm function, as reflected in the zona-free hamster egg penetration assay, and have investigated the possible mode of action of the white cells. Egg penetration rates decreased when white blood cells from fertile or potentially fertile donors were added to their sperm suspensions prior to preincubation and at insemination in the in vitro assay. Zona-free hamster egg penetration assay results were also inhibited when the supernatant from white blood cells incubated in Biggers, Whitten, and Whittingham (BWW) medium overnight were introduced to sperm-oocyte suspensions at insemination. Conversely, egg penetration rates were enhanced in samples from hypofertile individuals when white blood cell concentrations in the semen or WBC/sperm ratios were reduced, either by physical removal or as a result of antibiotic therapy. The physical presence of leukocytes, and possibly, the extracellular release of lysosomal enzymes may be responsible for the inhibitory effects in vitro. Although the mechanism(s) by which white blood cells interfere with the fertilizing capacity of spermatozoa are not clear, it is quite obvious that their presence in the in vitro environment is undesirable and can mask an individual's actual fertilizing potential.

Influence of vesicular‐arbuscular mycorrhiza on growth, water relations, and leaf orientation in leucaena leucocephala (lam.) de wit*

Abstract: Summary Plant growth characteristics, nutrient absorption and water relations were compared for plants of Leucaena leucocephala (Larn.) de Wir that were non-mycorthizal and those that were infected with the vesicular-arbuscular (VA) mycorrhizal fungus Glomus fasciculatum (Thaxter sensu Gerd.) Gerd. and Trappe. Mycorrhizal plants had substantially greater shoot and root dry weight, leaf area and root length than non-mycorrhizal plants, and alsos greater P, K, and Ca uptake. Leaf area was over five times greater and leaf conductance to water vapour diffusion was nearly twice as great for mycorrhizal plants, yet the difference between xylem pressure potential and soil water potential were considerably less in mycorrhizal plants than in non-mycorhizal plants. Stomatal responses to the humidity deficits of the air during the day were nearly twice as great in mycorrhizal plants. Leaflet folding and orientation responses to avoide direct sunlight during the day were also much greater in non-mycorrhizal plants. Lower leaf conductances and increased leaf folding leading to less absorption of sunlight may contribute significantly to the reduction in growth rate observed in non-mycorrhizal plants.

Reflectance spectroscopy in the visible and near-infrared (0.35–2.55 µm): Applications in carbonate petrology

Abstract: Reflectance spectroscopy in the visible and near-infrared (0.35 to 2.55 µm) offers a rapid, inexpensive, nondestructive tool for determining the mineralogy and for investigating the minor-element chemistry of the hard-to-discriminate carbonate minerals, and can, in one step, provide information previously obtainable only by the combined application of two or more analytical techniques. When light interacts with a mineral, certain wavelengths are preferentially absorbed. The positions and widths of absorptions due to vibrations of the carbonate radical, and the positions and shapes of absorptions due to transition metal cations, if present, can be used to determine mineralogy. Relative intensities of absorptions due to transition metal cations can be used to determine concentration of these cations. Because absorptions due to Fe2+ and Mn2+ occur in different regions of the spectrum, the presence of one cation does not interfere with analysis for the other. Detection limits for Mn2+ are about 0.1 wt% Mn and for Fe2+ are about 0.01 wt% Fe. This technique is also very sensitive to the presence of water and indicates that aqueous fluid inclusions are nearly ubiquitous in carbonate minerals and rocks. Spectra indicate that inclusions are particularly abundant in skeletal carbonates and that the quantity of inclusions in skeletal material varies from one type of organism to another. Spectra indicate that inclusions are lost during diagenesis of skeletal material, providing a new criterion for diagenetic studies.

Modified Input as an Aid to Comprehension

Abstract: Much work in the field of second language acquisition (SLA) has focused on the linguistic adjustments made by native speakers (NSs) when speaking to non-native speakers (NNSs) of that language. Modifications of speech to NNSs are usually assumed to be an attempt to make the target language more comprehensible. The study of second language teachers' classroom discourse has contributed to a thorough description of such modifications, which in general may be termed foreigner talk (FT).

Journey to adulthood

Abstract: The Growth and Development of Birds. By Raymond J. O'Connor. Wiley: 1984. Pp.315. 22, 34.15.

Kirchhoff–Helmholtz reflection seismograms in a laterally inhomogeneous multi‐layered elastic medium – I. Theory

Abstract: Summary. In a medium consisting of elastic layers with irregular interfaces, Kirchhoff-Helmholtz (KH) theory can be extended to synthesize the motion due to various generalized rays. An exact elastic form of the KH integral is first derived, then various asymptotic approximations are used to convert this integral into one which can be rapidly evaluated to give the motion of a single generalized ray. The approximations used are those of geometrical optics, for propagation across layers, and the Kirchhoff or tangent-plane approximation for propagation across boundaries. It is shown how the KH method leads naturally to a generalization of our usual notion of elastic reflection and transmission coefficients. The new coefficients are functions of both angle of incidence and angle of reflection or transmission and they are derived so as to obtain coordinate-free formulae that show clearly their relation to the conventional Snell’s law coefficients. The elastic KH method is applied first to the problem of a single interface, where its performance is compared to that of the Gaussian beam and Maslov methods. (For synthesizing reflections from irregular interfaces the KH method is superior because it includes signals diffracted from corners. However, when the interface is very smooth on the scale of a wavelength the Maslov and Gaussian beam methods are superior because they do not break down when there is a caustic on the reflector.) KH theory is then applied to a multilayered elastic medium and it is shown how the effects of frequency-dependent attenuation and dispersion can be incorporated into the theory by taking advantage of the approximately logarithmic variation of slowness with frequency in most earth materials. The limitations of the KH theory are discussed and some recent attempts to overcome these difficulties are reviewed. A new method for overcoming the problem of a caustic on the reflector becomes apparent when the KH integral is regarded as a member of a larger family of equivalent 1-fold integrals all of which are derivable from the same multifold path integral. Refracted or diving rays can be treated within the same formalism with equal benefit. For velocity models that are independent of one spatial direction (strike) a method is given for approximately converting 2-D results into 3-D results.

Waste-Water Injection: Geochemical and Biogeochemical Clogging Processes

Abstract: Examination of near-well clogging processes at two experimental injection sites in Hawaii shows that filtration of suspended solids is not a long-term cause of clogging While particulate filtration is probably a short-term cause of clogging at the start-up of injection, the injected organics are biodegraded once the microbial biomass becomes established The injection head gradient determined from monitoring wells shows that most of the initial head loss is immediately adjacent to the well, but that after several weeks it shifts to a region over 05 m from the well Denitrifying bacteria become sufficiently numerous to produce significant amounts of nitrogen gas, which in turn produces a gas-bound zone about 05 to 1 m from the well With continued injection the nitrogen gas-bound zone is slowly extended farther out into the injection stratum Dissolution of the carbonate aquifer also occurs, but its effects are partially masked by gas binding

Money Demand Predictability

Abstract: The performance of empirical money demand equations over the past decade raises serious questions about money demand predictability. A variety of specifications were presented to explain past episodes of apparent money demand instability, but their success in predicting future money demand is limited in most instances. In particular, the unprecedented decline in the velocity of Ml during 1982 and 1983 was not captured fullyby any of the previously-modified conventional specifications. This paper evaluates a variety of the approaches and specifications proposed inprevious money demand studies to explain the behavior of the narrowly defined money stock from the mid 1970's through 1983. The empirical results cast doubt on the appropriateness of the conventional money demand specification in both the pre- and post- 1974 periods.

Full text database retrieval performance

Abstract: Complete texts of many journals are now available for online searching. Most of these full text databases have been made available on the same or similar search systems that provide access to bibliographic information. The systems use inverted files that retain limited context information (e.g., paragraphs and location of words within paragraphs). The retrieval techniques used are simply those that were developed earlier for bibliographic databases. Retrieval relies on Boolean logic, word stem searching with truncation, and word proximity specification. Minor adjustments have been made for the display of full text databases, allowing words resulting in retrieval to be displayed in context; but changes have not been made in retrieval techniques. This is due to the reliance on search systems that provide access to many types of databases, all of which are by‐products of improved techniques for creating printed publications.

An approximation to the weight distribution of binary linear codes

Abstract: Binary primitive BCH codes form a large class of powerful error-correcting codes The weight distributions of primitive BCH codes are unknown except for some special classes, such as the single, double, triple error-correcting codes and some very low-rate primitive BCH codes However, asymptotic results for the weight distribution of a large subclass of primitive BCH codes have been derived by Sidel'nikov These results provide some insight into the weight structure of primitive BCH codes Sidel'nikov's approach is improved and applied to the weight distribution of any binary linear block code Then Sidel'nikov's results on the weight distributions of binary primitive BCH codes are improved and it is shown that the weights of a binary primitive code have approximate binomial distribution

Influence of Environmental Factors on Interstrain Competition in Rhizobium japonicum.

Abstract: The effect of several biotic and abiotic factors on the pattern of competition between two strains of Rhizobium japonicum was examined. In two Minnesota soils, Waseca and Waukegan, strain USDA 123 occupied 69% (Waseca) and 24% (Waukegan) of the root nodules on Glycine max L. Merrill cv. Chippewa. USDA 110 occupied 2% of the root nodules in the Waseca soil and 12% of the nodules in the Waukegan soil. Under a variety of other growth conditions—vermiculite, vermiculite amended with Waseca soil, and two Hawaiian soils devoid of naturalized Rhizobium japonicum strains—USDA 110 was more competitive than USDA 123. The addition of nitrate to or the presence of antibiotic-producing actinomycetes in the rhizosphere of soybeans did not affect the pattern of competition between the two strains. However, preexposure of young seedings to USDA 110 or USDA 123 before transplantation into soil altered the pattern of competition between the two strains significantly. In the Waseca soil, preexposure of cv. Chippewa to USDA 110 for 72 h increased the percentage of nodules occupied by USDA 110 from 2 to 55%. Similarly, in the Hawaiian soil Waimea, nodule occupancy by USDA 123 increased from 7 to 33% after a 72-h preexposure.

A cross-ethnic comparison of reasons given for using alcohol, not using alcohol or ceasing to use alcohol.

Abstract: In a study that included six different racial-ethnic groups in Hawaii, the reasons given by drinkers for drinking, abstainers for not drinking and former drinkers for ceasing to drink were assessed. Although there were group differences in frequencies of endorsement of given reasons for drinking, for not drinking or for ceasing to drink, the findings of similarity were most impressive. Drinkers, abstainers and former drinkers were similar across racial-ethnic groups in their proportions of endorsement of given reasons for drinking, abstaining or ceasing to use alcohol. Although reasons for drinking varied across racial-ethnic groups, they varied much more across groups that differed in alcohol consumption independent of ethnicity, with all reasons for drinking being more often endorsed as consumption increased. In addition, the citation of more pathological reasons for drinking was associated with a greater number of drinking problems.

Mating in the reef white-tip shark Triaenodon obesus

Abstract: Mating reef white-tip sharks, Triaenodon obesus, were observed and photographed in shallow waters of the Hawaiian Islands. The sharks copulated in a stationary parallel orientation with their heads on the bottom and bodies angled upwards approximately 45° into the water column. Pair contact during copulation was maintained by the male's left clasper anchored in the female's vent and by his tight oral grasp of the female's left pectoral fin. Results show that reposed sedentary modes of copulation are not limited to small species. In a reproductive context, biting behavior by male sharks functions as a premating releaser for female cooperation and for pair-contact maintenance during copulation.

The radioallergosorbent test (RAST) for the serological diagnosis of human anisakiasis.

Abstract: The serum of patients with parasitologically confirmed and one patient with a clinically presumptive case of anisakiasis were tested by the radioallergosorbent test (RAST) and counter-electrophoresis (CEP) for IgE and IgG antibodies, respectively, using antigens prepared from larval (L3) stage Anisakis simplex and larval (L2) stage Toxocara canis. All sera were RAST-positive to the A. simplex antigen and RAST-negative to the T. canis antigen. All sera were CEP-negative to both antigens. The presence of a specific IgE antibody suggests that the RAST could serve as a useful technique for the serodiagnosis of anisakiasis in man.