The construction and evaluation of a word pronunciation test for grades four, five, and six

Thesis (Ed.M.)--Boston Universit

A New Recipe for Obtaining Central Volume Densities of Prestellar Cores from Size Measurements

We propose a simple analytical method for estimating the central volume density of prestellar molecular cloud cores from their column density profiles. Prestellar cores feature a flat central part of the column density and volume density profiles of the same size indicating the existence of a uniform density inner region. The size of this region is set by the thermal pressure force which depends only on the central volume density and temperature of the core, and can provide a direct measurement of the central volume density. Thus a simple length measurement can immediately yield a central density estimate independent of any dynamical model for the core and without the need for fitting. Using the radius at which the column density is 90% of the central value as an estimate of the size of the flat inner part of the column density profile yields an estimate of the central volume density within a factor of 2 for well resolved cores.Comment: 4 pages, 4 figures, accepted for publication in ApJ Letter

Fantasy in stories spontaneously told by two relatively privileged groups of preschoolers

The purpose of this investigation was to duplicate the methodology of the Pitcher and Prelinger (1963) study, using their theoretical framework and category system, to examine the cultural impact upon the development of a group of socioeconomically disadvantaged preschool children as reflected in their fantasy products, specifically in their spontaneously told stories. The results for this disadvantaged group were analyzed separately, and were compared, where possible, with the Pitcher and Prelinger data on a socioeconomically privileged group of children. The general assumption underlying the hypotheses is that experiences due to cultural impact will be differentially expressed in the fantasy products of two socioeconomically different groups of children and will be reflected in their spontaneously told stories. The three null hypotheses formulated to test for differences within the less privileged group were: formal aspects of the stories, which presumably represent the child's ego structure, do not differ for boys and girls of the two age groups; story contents, which presumably represent the range of experience stored in the child, are independent of age, sex, and number of parents; and, the predominant psychosocial issue in the stories do not differ for boys and girls of the two age groups. The hypotheses formulated for comparison of the two different socioeconomic groups were: formal story aspects and psychosocial modalities do not differ for privilege group; and, story contents are independent of privilege group. The data (60 stories) were collected by the investigator using Jung's "free association" method and were rated by three judges using the Pitcher and Prelinger category system. Satisfactory interjudge reliability agreement was established on the ratings. Analysis of variance and the x² test of independence were used to analyze the data for tests within the less privileged group; whereas, analysis for the comparison of the two groups, with the exception of one modified x² test, had to be carried out on the basis of inspection alone due to the particular manner in which Pitcher and Prelinger reported their data. Stories were collected from 30 socioeconomically disadvantaged three- and four-year-old children enrolled in a United-Fund-supported day nursery in Portland, Oregon in the summer of 1964. The subjects, designated as socioeconomically disadvantaged (or less privileged) children were from families for whom the median annual take-home income is $3234.00; 53% of the sample were from single-parent families and 47% were from two-parent families; and, 21% of the parents had college or graduate education while 79% had high school education. The socioeconomically privileged subjects of the Pitcher and Prelinger study were from two-parent families of professional people, attended exclusive private nursery schools, and 60% of them showed superior capacity on intelligence tests. The results obtained within the less privileged group indicated that interaction of sex and age accounts for the significant difference in formal aspects as well as in relevant material on psychosocial modalities expressed in the stories; and, that the choice of the two major themes in the story contents category was dependent upon the sex of the child. Outstanding differences on the means for the sex and age groups were described and discussed. Findings on the comparison of data for the two relatively privileged groups showed that choice of themes in the stories was dependent on socioeconomic (privilege) group; the privileged group used themes reflecting socialization more often than the less privileged group and the less privileged group used themes centering in the self more often. Outstanding differences in the group means for the two relatively privileged groups were reported and discussed. Tentative explanations of the results in light of socio-cultural factors were considered and obvious weaknesses of the study were pointed up. It was concluded that fantasy products, in the form of spontaneously told stories, for the two relatively privileged socioeconomic groups of preschoolers do, at least to some degree, differentially reflect socio-cultural impact on child development

The Evolution of Density Structure of Starless and Protostellar Cores

We present a near-infrared extinction study of nine dense cores at evolutionary stages between starless to Class I. Our results show that the density structure of all but one observed cores can be modeled with a single power law rho \propto r^p between ~ 0.2R-R of the cores. The starless cores in our sample show two different types of density structures, one follows p ~ -1.0 and the other follows p ~ -2.5, while the protostellar cores all have p ~ -2.5. The similarity between the prestellar cores with p ~ -2.5 and protostellar cores implies that those prestellar cores could be evolving towards the protostellar stage. The slope of p ~ -2.5 is steeper than that of an singular isothermal sphere, which may be interpreted with the evolutionary model of cores with finite mass.Comment: 19 pages, 3 figures, accepted for publication in the Astrophysical Journa

Metaheuristic Algorithms to Enhance the Performance of a Feedforward Neural Network in Addressing Missing Hourly Precipitation

This research study investigates the implementation of three metaheuristic algorithms, namely, Grey wolf optimizer (GWO), Multi-verse optimizer (MVO), and Moth-flame optimisation (MFO), for coupling with a feedforward neural network (FNN) in addressing missing hourly rainfall observations, while overcoming the limitation of conventional training algorithm of artificial neural network that often traps in local optima. The proposed GWOFNN, MVOFNN, and MFOFNN were compared against the conventional Levenberg Marquardt Feedforward Neural Network (LMFNN) in addressing the artificially introduced missing hourly rainfall records of Kuching Third Mile Station. The findings show that the proposed approaches are superior to LMFNN in predicting the 20% hourly rainfall observations in terms of mean absolute error (MAE) and coefficient of correlation (r). The best performance ANN model is GWOFNN, followed with MVOFNN, MFOFNN and lastly LMFNN

Metaheuristic Algorithms to Enhance the Performance of a Feedforward Neural Network in Addressing Missing Hourly Precipitation

This research study investigates the implementation of three metaheuristic algorithms, namely, Grey wolf optimizer (GWO), Multi-verse optimizer (MVO), and Moth-flame optimisation (MFO), for coupling with a feedforward neural network (FNN) in addressing missing hourly rainfall observations, while overcoming the limitation of conventional training algorithm of artificial neural network that often traps in local optima. The proposed GWOFNN, MVOFNN, and MFOFNN were compared against the conventional Levenberg Marquardt Feedforward Neural Network (LMFNN) in addressing the artificially introduced missing hourly rainfall records of Kuching Third Mile Station. The findings show that the proposed approaches are superior to LMFNN in predicting the 20% hourly rainfall observations in terms of mean absolute error (MAE) and coefficient of correlation (r). The best performance ANN model is GWOFNN, followed with MVOFNN, MFOFNN and lastly LMFNN

Mutations of Francisella novicida that Alter the Mechanism of Its Phagocytosis by Murine Macrophages

Infection with the bacterial pathogen Francisella tularensis tularensis (F. tularensis) causes tularemia, a serious and debilitating disease. Francisella tularensis novicida strain U112 (abbreviated F. novicida), which is closely related to F. tularensis, is pathogenic for mice but not for man, making it an ideal model system for tularemia. Intracellular pathogens like Francisella inhibit the innate immune response, thereby avoiding immune recognition and death of the infected cell. Because activation of inflammatory pathways may lead to cell death, we reasoned that we could identify bacterial genes involved in inhibiting inflammation by isolating mutants that killed infected cells faster than the wild-type parent. We screened a comprehensive transposon library of F. novicida for mutant strains that increased the rate of cell death following infection in J774 macrophage-like cells, as compared to wild-type F. novicida. Mutations in 28 genes were identified as being hypercytotoxic to both J774 and primary macrophages of which 12 were less virulent in a mouse infection model. Surprisingly, we found that F. novicida with mutations in four genes (lpcC, manB, manC and kdtA) were taken up by and killed macrophages at a much higher rate than the parent strain, even upon treatment with cytochalasin D (cytD), a classic inhibitor of macrophage phagocytosis. At least 10-fold more mutant bacteria were internalized by macrophages as compared to the parent strain if the bacteria were first fixed with formaldehyde, suggesting a surface structure is required for the high phagocytosis rate. However, bacteria were required to be viable for macrophage toxicity. The four mutant strains do not make a complete LPS but instead have an exposed lipid A. Interestingly, other mutations that result in an exposed LPS core were not taken up at increased frequency nor did they kill host cells more than the parent. These results suggest an alternative, more efficient macrophage uptake mechanism for Francisella that requires exposure of a specific bacterial surface structure(s) but results in increased cell death following internalization of live bacteria

The Initial Conditions of Clustered Star Formation. II. N2H+ Observations of the Ophiuchus B Core

We present a Nobeyama 45 m Radio Telescope map and Australia Telescope Compact Array pointed observations of N2H+ 1-0 emission towards the clustered, low mass star forming Oph B Core within the Ophiuchus molecular cloud. We compare these data with previously published results of high resolution NH3 (1,1) and (2,2) observations in Oph B. We use 3D Clumpfind to identify emission features in the single-dish N2H+ map, and find that the N2H+ `clumps' match well similar features previously identified in NH3 (1,1) emission, but are frequently offset to clumps identified at similar resolution in 850 micron continuum emission. Wide line widths in the Oph B2 sub-Core indicate non-thermal motions dominate the Core kinematics, and remain transonic at densities n ~ 3 x 10^5 cm^-3 with large scatter and no trend with N(H2). Non-thermal motions in Oph B1 and B3 are subsonic with little variation, but also show no trend with H2 column density. Over all Oph B, non-thermal N2H+ line widths are substantially narrower than those traced by NH3, making it unlikely NH3 and N2H+ trace the same material, but the v_LSR of both species agree well. We find evidence for accretion in Oph B1 from the surrounding ambient gas. The NH3/N2H+ abundance ratio is larger towards starless Oph B1 than towards protostellar Oph B2, similar to recent observational results in other star-forming regions. Small-scale structure is found in the ATCA N2H+ 1-0 emission, where emission peaks are again offset from continuum emission. In particular, the ~1 M_Sun B2-MM8 clump is associated with a N2H+ emission minimum and surrounded by a broken ring-like N2H+ emission structure, suggestive of N2H+ depletion. We find a strong general trend of decreasing N2H+ abundance with increasing N(H2) in Oph B which matches that found for NH3.Comment: 55 pages (manuscript), 15 figures, ApJ accepte

The Initial Conditions of Clustered Star Formation I: NH3 Observations of Dense Cores in Ophiuchus

We present combined interferometer and single dish telescope data of NH3 (J,K) = (1,1) and (2,2) emission towards the clustered star forming Ophiuchus B, C and F Cores at high spatial resolution (~1200 AU) using the Australia Telescope Compact Array, the Very Large Array, and the Green Bank Telescope. While the large scale features of the NH3 (1,1) integrated intensity appear similar to 850 micron continuum emission maps of the Cores, on 15" (1800 AU) scales we find significant discrepancies between the dense gas tracers in Oph B, but good correspondence in Oph C and F. Using the Clumpfind structure identifying algorithm, we identify 15 NH3 clumps in Oph B, and 3 each in Oph C and F. Only five of the Oph B NH3 clumps are coincident within 30" (3600 AU) of a submillimeter clump. We find v_LSR varies little across any of the Cores, and additionally varies by only ~1.5 km/s between them. The observed NH3 line widths within the Oph B and F Cores are generally large and often mildly supersonic, while Oph C is characterized by narrow line widths which decrease to nearly thermal values. We find several regions of localized narrow line emission (\Delta v < 0.4 km/s), some of which are associated with NH3 clumps. We derive the kinetic temperatures of the gas, and find they are remarkably constant across Oph B and F, with a warmer mean value (T_K = 15 K) than typically found in isolated regions and consistent with previous results in clustered regions. Oph C, however, has a mean T_K = 12 K, decreasing to a minimum T_K = 9.4 K towards the submillimeter continuum peak, similar to previous studies of isolated starless cores. There is no significant difference in temperature towards protostars embedded in the Cores. [Abridged]Comment: ApJ, accepte

Feasibility of polyclonal avian immunoglobulins (IgY) as prophylaxis against human norovirus infection

Background: Human norovirus (HuNoV) is the leading viral cause of diarrhea, with GII.4 as the predominant genotype of HuNoV outbreaks globally. However, new genogroup variants emerge periodically, complicating the development of anti-HuNoV vaccines; other prophylactic or therapeutic medications specifically for HuNoV disease are lacking. Passive immunization using oral anti-HuNoV antibodies may be a rational alternative. Here, we explore the feasibility of using avian immunoglobulins (IgY) for preventing HuNoV infection in vitro in a human intestinal enteroid (HIE) model. Methods: Hens were immunized with virus-like particles (VLP) of a GII.4 HuNoV strain (GII.4/CHDC2094/1974/US) by intramuscular injection. The resulting IgY was evaluated for inhibition of binding to histo-blood group antigens (HBGA) and viral neutralization against representative GII.4 and GII.6 clinical isolates, using an HIE model. Results: IgY titers were detected by three weeks following initial immunization, persisting at levels of 1:221 (1:2,097,152) from 9 weeks to 23 weeks. Anti-HuNoV IgY significantly (p < 0.05) blocked VLP adhesion to HBGA up to 1:12,048 dilution (0.005 mg/mL), and significantly (p < 0.05) inhibited replication of HuNoV GII.4[P16] Sydney 2012 in HIEs up to 1:128 dilution (0.08 mg/mL). Neutralization was not detected against genotype GII.6. Conclusions: We demonstrate the feasibility of IgY for preventing infection of HIE by HuNoV GII.4. Clinical preparations should cover multiple circulating HuNoV genotypes for comprehensive effects. Plans for animal studies are underway.Instituto de VirologíaFil: Artman, Chad. Scaled Microbiomics; Estados UnidosFil: Idegwu, Nnebuefe. Scaled Microbiomics; Estados UnidosFil: Brumfield, Kyle D. College Park Campus. University of Maryland. Maryland Pathogen Research Institute; Estados UnidosFil: Brumfield, Kyle D. College Park Campus. University of Maryland. University of Maryland Institute for Advanced Computer Studies; Estados UnidosFil: Lai, Ken. University of Saskatchewan. Vaccine and Infectious Disease Organization; CanadáFil: Hauta, Shirley. University of Saskatchewan. Vaccine and Infectious Disease Organization; CanadáFil: Falzarano, Darryl. University of Saskatchewan. Vaccine and Infectious Disease Organization; CanadáFil: Falzarano, Darryl. University of Saskatchewan. Western College of Veterinary Medicine. Department of Veterinary Microbiology; CanadáFil: Parreño, Gladys Viviana. Virginia-Maryland College of Veterinary Medicine. Department of Biomedical Sciences and Pathobiology; Estados UnidosFil: Parreño, Gladys Viviana. Instituto Nacional de Tecnología Agropecuaria (INTA). INCUINTA. Instituto de Virologia e Innovaciones Tecnologicas (IVIT); ArgentinaFil: Yuan, Lijuan. Virginia-Maryland College of Veterinary Medicine. Department of Biomedical Sciences and Pathobiology; Estados UnidosFil: Geyer, James D. University of Alabama. College of Community Health Science. Institute for Rural Health Research; Estados UnidosFil: Goepp, Julius G. Scaled Microbiomics; Estados Unido