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Biomedical subjects

E G Williams

Publications and source records attributed to E G Williams.

At least 19 recordsLinked to original sources
PubMed2001

Effects of an urban high school-based child care center on self-selected adolescent parents and their children.

This study examined the effects of an urban high school-based child care center on parenting teens and their children enrolled during 1995-1998. Retrospective record review of 52 low-income, urban adolescent parents enrolled at the Celotto Child Care Center (CCCC) during the period of study was conducted from the CCCC and the high school records. Mean age of the student parents was 17 years (s.d. = 1.3) and mean grade level was 11.2 (s.d. = 1). Most parents were female (98%) and African American (62%). Children enrolled at CCCC had a mean age of 10 months (s.d. = 10.8). Students using the services of CCCC showed improvement in overall grade point averages, and 100% were educationally successful as defined by promotion to the next grade or graduating from high school. None of the students experienced a repeat childbirth during the period of CCCC enrollment. Ninety percent of children were up-to-date with pediatric health visits and immunizations. These results lend strong support to the importance of extending child care and social support services to teen parents, and for the implementation of high school-based child care centers as alternative sites for these critically important services.

Adolescent↗
PubMed2001

Regularization methods for near-field acoustical holography.

The reconstruction of the pressure and normal surface velocity provided by near-field acoustical holography (NAH) from pressure measurements made near a vibrating structure is a linear, ill-posed inverse problem due to the existence of strongly decaying, evanescentlike waves. Regularization provides a technique of overcoming the ill-posedness and generates a solution to the linear problem in an automated way. We present four robust methods for regularization; the standard Tikhonov procedure along with a novel improved version, Landweber iteration, and the conjugate gradient approach. Each of these approaches can be applied to all forms of interior or exterior NAH problems; planar, cylindrical, spherical, and conformal. We also study two parameter selection procedures, the Morozov discrepancy principle and the generalized cross validation, which are crucial to any regularization theory. In particular, we concentrate here on planar and cylindrical holography. These forms of NAH which rely on the discrete Fourier transform are important due to their popularity and to their tremendous computational speed. In order to use regularization theory for the separable geometry problems we reformulate the equations of planar, cylindrical, and spherical NAH into an eigenvalue problem. The resulting eigenvalues and eigenvectors couple easily to regularization theory, which can be incorporated into the NAH software with little sacrifice in computational speed. The resulting complete automation of the NAH algorithm for both separable and nonseparable geometries overcomes the last significant hurdle for NAH.

Journal Article↗
PubMed2000

Interior near-field acoustical holography in flight.

In this paper boundary element methods (BEM) are mated with near-field acoustical holography (NAH) in order to determine the normal velocity over a large area of a fuselage of a turboprop airplane from a measurement of the pressure (hologram) on a concentric surface in the interior of the aircraft. This work represents the first time NAH has been applied in situ, in-flight. The normal fuselage velocity was successfully reconstructed at the blade passage frequency (BPF) of the propeller and its first two harmonics. This reconstructed velocity reveals structure-borne and airborne sound-transmission paths from the engine to the interior space.

Acceleration↗
PubMed1992

Techniques for clearing ovules for studies of megagametophyte and early postfertilization development in Rhododendron.

Using ovule clearing, more than 33,600 ovules of Rhododendron nuttallii T. W. Booth (Ericaceae) were examined for megagametophyte and early postfertilization stages at daily intervals from anthesis until 3 weeks after pollination. Pretreatments with amyloglucosidase to digest integumentary and gametophyte starch and Stockwell's bleach to remove tannins from the integumentary epidermis were necessary. Ovules were cleared by a combination or modifications of Herr's four-and-a-half or Stelly's hemalum-methyl salicylate techniques and were observed using differential interference contrast optics. The method proved suitable for large-scale quantitative studies of ovule development and fertilization. A general protocol is suggested as a starting point for ovule clearing studies.

Fertilization↗
PubMed1991

Vocal cord paralysis in the Shy-Drager syndrome. A cause of postoperative respiratory obstruction.

A case is presented in which unexpected and persistent postoperative respiratory problems led to the finding of bilateral abductor vocal cord paralysis and confirmed the diagnosis of the Shy-Drager syndrome. Anaesthetists should be aware that vocal cord paralysis may be a feature of this uncommon condition, and should consider the possibility of glottic obstruction as a cause of ventilatory difficulties.

Humans↗
PubMed1985

Applications of fluorochromes to pollen biology. II. The DNA probes ethidium bromide and Hoechst 33258 in conjunction with the callose-specific aniline blue fluorochrome.

Techniques are described for detection of pollen grain and pollen tube nuclei using the fluorescent DNA probes ethidium bromide or Hoechst 33258, in conjunction with the aniline blue fluorochrome sirofluor, which stains the callose component of pollen tube walls and plugs. The DNA probes, which may be used either as vital stains or following fixation, permit discrimination between vegetative and generative or sperm nuclei. Double staining with sirofluor allows location of nuclei within pollen tubes grown in vitro, and when used after pollination enables the viewer to discriminate between nuclei within the pollen tube vs. nuclei of the pistil tissue.

Benzenesulfonates↗
PubMed1984

Post-pollination callose development in ovules of Rhododendron and Ledum (Ericaceae): zygote special wall.

In Rhododendron spp. and Ledum groenlandicum a callose wall is laid down around the zygote in the first 2 days after fertilization. The periodic acid/Schiff-positive, aniline blue-fluorescence-positive callosic wall is initiated adjacent to the degenerating synergid, extends to cover the entire zygote surface, and remains visible during the initiation of embryogeny as the zygote elongates before the first proembryonal division. Unfertilized ovules show eventual callose deposition in the ovule wall cells during senescence in undeveloped abscising pistils, but show no development of callose within the embryo sac. Possible roles of a zygote special callose wall are discussed.

Cell Wall↗
PubMed1983

Adolescent loneliness.

The purpose of this study was to investigate the phenomenon of loneliness in delinquent adolescents with regard to types of delinquency offenses committed, demographic characteristics, and personality characteristics in the areas of interpersonal needs for inclusion, control, and affection. The types of delinquency offenses were categorized as burglary, runaway, drugs, assault, and incorrigible. The demographic variables examined were age, sex, race, family rank or birth order, family structure in terms of parental presence, family income level, religion, and geographic locale. A sample of 98 adolescents was obtained from juvenile detention facilities in three metropolitan areas in the United States. Subjects ranged in age from 12 to 18. Subjects were asked to complete the Loneliness Questionnaire as a self-reported measure of loneliness. Subjects also provided information about themselves relative to demographic characteristics and completed the FIRO-B Questionnaire, which measured interpersonal needs for inclusion, control, and affection. The results revealed no significant differences with regard to any of the demographic variables when the effect of each was considered alone. However, there was a significant effect on loneliness by income when considered jointly with other demographic variables. Adolescents from the middle income group expressed more loneliness than those from the upper and lower income groups. No significant differences were observed with regard to personality characteristics related to interpersonal needs for inclusion and affection, but delinquent adolescents with medium to high needs for control indicated significantly more feelings of loneliness than delinquent adolescents with low needs for control.

Adolescent↗
PubMed1978

Leadership and productivity in planning organizations: a case study.

This paper presents the findings of a case study dealing mainly with the effects of two divergent leadership styles on the productivity of a planning organization. Changes in various kinds of participation in the agency's activities--an important side effect--are also linked to the two leadership patterns. The agency studied, a private health and welfare council in a medium-sized American city, varied considerably in its output of planning activities and decision making depending on whether it had a participative or a directive leader. The results indicated that there was a trade-off between such highly revered social values as leadership and the extent of participation by staff, board members, and local agency administrators. Implications focus on ways to achieve diversity in communication style among managers and the role of productivity measures in determining the overall effectiveness of planning agencies.

Administrative Personnel↗
PubMed1973

Diazoxide.

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Diazoxide↗
PubMed1972

Atrial dissociation.

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Arrhythmias, Cardiac↗