RESUMEN
BACKGROUND: This study investigated whether Nebraska schools with Student Assistance Programs (SAP) are associated with reduced adolescent alcohol use and a higher level of academic achievement than students from schools without a SAP. METHODS: In 1992, the Toward a Drug Free Nebraska (TDFN) survey was administered to 3,454 students in grades seven to twelve at eighty-three Nebraska schools. A second survey, the TDFN "team activity report" collected from each school's team, the presence of a SAP (n = 34 schools) or absence of a SAP (n = 49 schools). Student responses for alcohol use and academic achievements were linked with the presence of a SAP through use of a school identification number on both surveys. RESULTS: Students from schools with a SAP reported a lower use of alcohol in the last thirty days, compared with students from schools without a SAP program (p < 0.05), and they also reported a significant difference in academic achievement (p < 0.05). CONCLUSIONS: While this study used post hoc analysis of data, the results suggest lower alcohol use and higher academic achievement among students from SAP schools. Given SAPs' popularity, these trends suggest that further research should be conducted to demonstrate the effectiveness of student assistance programs.
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Consumo de Bebidas Alcohólicas/prevención & control , Educación en Salud , Servicios de Salud Escolar/organización & administración , Adolescente , Distribución de Chi-Cuadrado , Escolaridad , Femenino , Humanos , Masculino , Nebraska , Evaluación de Programas y Proyectos de Salud , Encuestas y CuestionariosRESUMEN
OBJECTIVE: Determination of skeletal or bone age is often used in pediatrics and orthopedics. The most commonly used bone age standards in the United States, those published by Greulich and Pyle, were derived from white children of the upper socioeconomic class in 1931-1942. We examined whether these standards apply to the current assessment of bone age in children of diverse ethnicity. MATERIALS AND METHODS: Hand radiographs of children less than 19 years old at our institution were evaluated for bone age using the standards of Greulich and Pyle. Differences between bone age and chronologic age were calculated, and the mean differences were compared among subgroups of children on the basis of sex, age, and ethnicity. RESULTS: In Asian and white girls, bone age approximated chronologic age throughout childhood, with the only significant discrepancy being in adolescent white girls, in whom bone age exceeded chronologic age by an average of 4 months. In black girls, bone age exceeded chronologic age except during middle childhood. In late childhood and adolescence, bone age exceeded chronologic age by approximately 10 months. In Hispanic adolescent girls, bone age exceeded chronologic age by nearly 9 months. In black adolescent boys, bone age exceeded chronologic age by 5 months, with no significant discrepancies between bone age and chronologic age at other ages. In white preadolescent boys, bone age lagged behind chronologic age to a statistically significant degree, ranging from approximately 4 to 8 months. Preadolescent Asian boys also showed significant delays in bone age, particularly in middle childhood, when bone age lagged behind chronologic age by nearly 15 months. In adolescent Asian boys, bone age exceeded chronologic age by 9 months 15 days. In adolescent Hispanic boys, bone age exceeded chronologic age by 11 months 15 days. In younger Hispanic boys, delays in bone age occurred but were significant only in early childhood (4-month delay). CONCLUSION: Using the standards of Greulich and Pyle to determine bone age must be done with reservations, particularly in black and Hispanic girls and in Asian and Hispanic boys in late childhood and adolescence, when bone age may exceed chronologic age by 9 months to 11 months 15 days.
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Determinación de la Edad por el Esqueleto , Etnicidad , Mano/diagnóstico por imagen , Adolescente , Pueblo Asiatico , Población Negra , Niño , Preescolar , Femenino , Humanos , Lactante , América Latina/etnología , Masculino , Estados Unidos , Población BlancaRESUMEN
The extent of anabolic steroid use among adolescent sports participants and nonparticipants in Nebraska schools was studied. The Nebraska Secondary School Survey administered in 1991 contained 19 new items designed to determine rates of use of anabolic steroids and to measure participation in school sports. Schools participating in the survey are part of the Toward a Drug Free Nebraska training project; when the 1991 survey was conducted, training did not address ergogenic drug use. The survey was administered on a voluntary and confidential basis to Nebraska students in grades 7 through 12. A total of 4722 students in 62 secondary schools were surveyed; 3183 (67.4%) identified themselves as participants in school-sponsored sports. Of all the respondents, 117 (2.5%) reported having used anabolic steroids in the preceding 30 days. Some 4.5% of all the male respondents were steroid users, versus 0.8% of all the females. Of the students who reported using anabolic steroids, 72.6% were sports participants. Steroid users, whether they participated in sports or not, were more likely to use alcohol, tobacco, and other drugs than were nonusers of steroids. Among sports participants and nonparticipants, anabolic steroid users were more likely than nonusers to report acting violently. Nebraska students (grades 7 through 12) who participated in school-sponsored sports were more likely than non-participants to use anabolic steroids. Steroid-using athletes were more likely to use alcohol, tobacco, and other drugs than athletes who did not use steroids.
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Anabolizantes , Trastornos Relacionados con Sustancias/epidemiología , Adolescente , Femenino , Humanos , Incidencia , Masculino , Nebraska/epidemiología , Deportes , Encuestas y CuestionariosRESUMEN
A one-dimensional representation of protein structure in terms of angles between C alpha-C alpha links in a two-dimensional representation describes tertiary structure to an accuracy of approximately 3 A.
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Modelos Estructurales , Estructura Terciaria de Proteína , Proteínas/química , Uteroglobina/química , Animales , Conejos , Reproducibilidad de los ResultadosRESUMEN
Using a nonlinear mapping technique, we demonstrate that proteins folded in two dimensions display the same overall structural features as their three-dimensional counterparts. The two-dimensional representation of protein structure provides a novel way to visualize structural as well as distance information. It may also provide a link for deriving three-dimensional structure from amino acid sequence.
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Gráficos por Computador , Simulación por Computador , Modelos Moleculares , Proteínas/química , Pliegue de Proteína , Estructura Secundaria de ProteínaRESUMEN
A feed-forward neural network has been employed for protein secondary structure prediction. Attempts were made to improve on previous prediction accuracies using a hierarchical mixture of experts (HME). In this method input data are clustered and used to train a series of different networks. Application of an HME to the prediction of protein secondary structure is shown to provide no advantages over a single network. We have also tried various new input representations, chosen to incorporate the effect of residues a long distance away in the one-dimensional amino acid chain. Prediction accuracy using these methods is comparable to that achieved by other neural networks.
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Redes Neurales de la Computación , Estructura Secundaria de ProteínaRESUMEN
OBJECTIVE: We evaluated the effect of particle size on MR contrast-enhancing properties of arabinogalactan-coated superparamagnetic iron oxide (AG-SPIO) in tumor-bearing rats. MATERIALS AND METHODS: T2*-weighted gradient-recalled echo MR studies were performed on rats with surgically implanted liver tumors before and after AG-SPIO administration. Contrast-to-noise ratio (CNR) and percent contrast enhancement (PCE) were calculated for animals given small (15.7 +/- 9.5 nm: n = 6), medium (49.1 +/- 19.7 nm; n = 4), and large (86.9 +/- 27.5 nm; n = 4) particles intravenously (10 mumol Fe/kg). RESULTS: Postcontrast CNRs were 15.8 +/- 6.9, 8.9 +/- 4.1, and 10.0 +/- 1.8 for small, medium, and large particle groups, respectively. The PCE was -60.0 +/- 3.3, -75.5 +/- 7.9, and -80.5 +/- 1.2%. There was a significant difference in preversus postcontrast CNR for all particle sizes (p < 0.001) and in PCE for small particles as compared with the two larger sizes (p < 0.001). There was no between-group statistical difference in postcontrast CNR for any particle size. CONCLUSION: Larger AG-SPIO particles slightly improve liver contrast enhancement, but have no significant effect on hepatic lesion detection as assessed by CNR.
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Medios de Contraste , Hierro , Hígado/patología , Imagen por Resonancia Magnética , Óxidos , Animales , Femenino , Óxido Ferrosoférrico , Galactanos , Neoplasias Hepáticas Experimentales/diagnóstico , Ratas , Ratas Endogámicas F344RESUMEN
RATIONALE AND OBJECTIVES: Electromagnetic flowmeters have been used for many years as a standard method to determine blood flow in animal models. The use of a modified probe to measure electromagnetic induction in response to an external, large direct current (DC) field magnetic resonance (MR) imaging system was investigated. METHODS: Extracted sheep iliac vessels were inserted into a pumped saline circuit with a modified probe and placed into a 2.0-T MR research imaging system. Voltage readings were collected at various flow rates ranging from 100 to 400 ml/min. Actual flows were measured with a graduated cylinder. RESULTS: A correlation of .937 (p < .001) was observed between the measured voltage changes and the actual flows. Baseline drift was also linear and within specified limits. CONCLUSION: The results indicate that electromagnetic induction in a conductive fluid can be accurately measured using electrodes and an MR imaging system and that this technique provides possible opportunities for in situ flow measurements in humans.
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Velocidad del Flujo Sanguíneo/fisiología , Fenómenos Electromagnéticos/instrumentación , Imagen por Resonancia Magnética , Animales , Diseño de Equipo , Estudios de Factibilidad , Arteria Ilíaca/fisiología , Análisis de Regresión , OvinosRESUMEN
Self-organizing maps generated by Kohonen neural networks provide a method for transforming multidimensional problems into lower dimensional problems. Here, a Kohonen network is used to generate two-dimensional representations of the electrostatic potential about the ring structures of histamine H2 agonists. Previous work by J. Gasteiger and X. Li (Angew. Chem. Int. Ed. Engl. 1994, 33, 643) has shown the usefulness of such a method for classifying molecules as muscarinic or nicotinic agonists. Here, the method is extended to rank histamine H2 agonists in order of biological activity.
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Gráficos por Computador , Electroquímica , Agonistas de los Receptores Histamínicos/química , Agonistas de los Receptores Histamínicos/farmacología , Modelos Químicos , Redes Neurales de la Computación , Relación Estructura-ActividadRESUMEN
BACKGROUND: A process evaluation of the Nebraska Drug Free School/Community Residential Team Training Project is described. This training project utilizes a "system approach" in the formation and implementation of localized strategic (action) plans targeting alcohol and other drug (AOD) abuse prevention. METHODS: In June of 1990, training participants completed a pre-post survey in conjunction with the four-day training. The majority of the participants (51.2%) were teachers, 19.2 percent were parents, 13.6 percent administrators, and 9.6 percent were counselors. RESULTS: Although the overall attitudes of the participants (N = 125) were positive initially, they became even more so by the end of the training (N = 121). Prior to training participants felt they could have a significant impact on their local AOD abuse problem, and this attitude became more positive by the completion of training (p < 0.05). CONCLUSIONS: The Nebraska team training process immerses team members in an active planning process allowing teams to develop a plan of action for their school and community. During this process, participants experience a positive growth in attitudes reflecting not only the training experience itself, but even more importantly their ability to meaningfully affect AOD abuse and related destructive behaviors in their homes, schools, and community.