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PubMedDate not supplied

The utility of kindergarten teacher ratings for predicting low academic achievement in first grade.

The purpose of this study was to assess the predictive value of kindergarten teachers' ratings of pupils for later first-grade academic achievement. Kindergarten students were rated by their teachers on a variety of variables, including math and reading performance, teacher concerns, and amount of learning relative to peers. These variables were then analyzed with respect to outcome measures for math and reading ability administered in the first grade. The teachers' ratings of academic performance were significantly correlated with scores on the outcome measures. Analyses were also carried out to determine sensitivity, specificity, and predictive values of the different teacher ratings. The results indicated high overall accuracy, sensitivity, specificity, and negative predictive value for the ratings. Positive predictive value tended to be lower. A recommendation to follow from these results is that teacher ratings of this sort be used to determine which children should receive cognitive screening measures to further enhance identification of children at risk for learning disability. However, this recommendation is limited by the lack of empirically supported screening measures for math disability versus well-supported screening tools for reading disability.

Child↗
PubMed1980

Studies of familial and nonfamilial alcoholism. I. Demographic studies.

This study supports the notion that a group of familial alcoholics can be isolated that is significantly different on many parameters from nonfamilial alcoholics and that this may have implications for diagnostic classification, prognosis, and treatment. A group of 7,064 military men admitted to naval residential alcoholic treatment programs were categorized into two groups: (1) those who reported no incidence of any family history of problems related to drinking; and (2) those who reported at least one family member with a possible drinking problem. These two cohort groups were compared in terms of demographic and behavioral variables obtained from a biographical questionnaire. It was found that the group with a family history of alcoholism had more severe symptomatology of alcoholism, more antisocial behavior, worse academic and social performance in school, less stable employment histories, more severe physical symptoms related to alcohol, and a background of larger families with lower socioeconomic status and more psychopathology.

Alcoholism↗
PubMed1999

Neuropsychologic deficits in children with Langerhans cell histiocytosis.

BACKGROUND: Manifestations of Langerhans cell histiocytosis (LCH) in children range from only a rash, to bony lesions accompanied by pain, to major organ disease. When the central nervous system (CNS) is affected, the LCH patient may exhibit signs and symptoms of hypothalamic and pituitary dysfunction (most often resulting in diabetes insipidus or other endocrinopathies) or more global neurologic and neuropsychologic sequelae. Surprisingly, researchers have only recently begun to examine the neuropsychologic manifestations of the disease, but early findings suggest that they may, in fact, be significant in a small percentage of children with LCH. PROCEDURE: We evaluated two CNS-positive patients with LCH and long-term intermittent treatments, using extensive neuropsychologic assessments, including intellectual functioning, memory, visual-motor functioning, attention and concentration, sensory and motor performance, and gross academic achievement. Objective measures of behavior were obtained through parental report. Neuroradiologic imaging was obtained concurrently with the neuropsychologic evaluations. RESULTS: The neuropsychologic assessments indicated significant deficits in a number of the measured areas of functioning. Global cognitive deficiencies in full-scale IQ were identified, as were deficits in memory, attention/concentration, and perceptual-organizational capabilities. Similarities were noted in the patterns of deficits obtained with both patients, despite differences in the pathophysiology of their disease. Behavioral functioning in both children had suffered, presumably in relation to the neuropsychologic deficits. There were radiologic findings of gross cerebellar white matter damage in one patient, in addition to focal (e.g., hypothalamic) lesions in the other. CONCLUSIONS: LCH has an adverse impact on cognitive functions in some children with evidence of CNS involvement, and further study into the etiology, incidence, and means of remedial intervention is needed.

Adolescent↗
PubMed1995

Absence of linkage of apparently single gene mediated ADHD with the human syntenic region of the mouse mutant Coloboma.

Attention deficit disorder (ADHD) is a complex biobehavioral phenotype which affects up to 8% of the general population and often impairs social, academic, and job performance. Its origins are heterogeneous, but a significant genetic component is suggested by family and twin studies. The murine strain, coloboma, displays a spontaneously hyperactive phenotype that is responsive to dextroamphetamine and has been proposed as a genetic model for ADHD. Coloboma is a semi-dominant mutation that is caused by a hemizygous deletion of the SNAP-25 and other genes on mouse chromosome 2q. To test the possibility that the human homolog of the mouse coloboma gene(s) could be responsible for ADHD, we have carried out linkage studies with polymorphic markers in the region syntenic to coloboma (20p11-p12). Five families in which the pattern of inheritance of ADHD appears to be autosomal dominant were studied. Segregation analysis of the traits studied suggested that the best fitting model was a sex-influenced, single gene, Mendelian pattern. Several genetic models were evaluated based on estimates of penetrance, phenocopy rate, and allele frequency derived from our patient population and those of other investigators. No significant linkage was detected between the disease locus and markers spanning this chromosome 20 interval.

Adolescent↗
PubMed1996

Response to higher doses of interferon alfa-2b in patients with chronic hepatitis C: a randomized multicenter trial. Hepatitis Interventional Therapy Group.

To evaluate response rates to 3, 5, or 10 million units (MU) of interferon alfa-2b, given thrice weekly, and to determine whether higher doses of interferon increase the likelihood or durability of the response, a multicenter, randomized trial was performed at nine academic medical centers in the United States. Two hundred forty eight patients with chronic hepatitis C were randomized to receive 3, 5, or 10 MU of interferon alfa-2b thrice weekly for 12 weeks. Based on the alanine aminotransferase (ALT) response at treatment-week 12, the patients were rerandomized to additional therapy at the same or at increased doses for an additional 12 to 36 weeks; in the case of no response to the highest dose, the patients were discontinued from the study. Serum ALT concentrations and liver histology were measured. The overall complete response rates to 3, 5, or 10 MU were not different at treatment-week 12 (31% vs. 42% vs. 40%, not significant). The majority of week-12 responders continued to respond during additional treatment. When the treatment was discontinued, 15.4% to 19.0% of patients maintained their response. Of the nonresponders to 3 MU at week 12, who were continued on 3 MU for an additional 12 weeks, none responded. However, response to additional therapy occurred in 12% of week-12 nonresponders, whose dose was escalated from 3 or 5 MU to 10 MU. The only baseline features associated with the treatment response were the absence of fibrosis or cirrhosis on the pretreatment liver biopsy and viral genotype. We conclude that the initial response to interferon in patients with chronic hepatitis C is not increased by treatment with higher doses of the drug. Patients who do not respond to 3 MU by treatment-week 12 will not respond with continued therapy at that dose; however, a proportion of patients who do not respond to 12 weeks of treatment with 3 or 5 MU may respond to higher doses. Although the long-term sustained response rates are marginally increased with interferon doses above 3 MU three times per week, the side effects are difficult to tolerate. The analysis of baseline factors in relation to response identified no single baseline factor associated with a low-enough response rate to warrant withholding interferon therapy from patients with chronic hepatitis C.

Adolescent↗
PubMed1998

Priming and aging: an electrophysiological investigation of N400 and recall.

Twenty young (20.5 years) and 20 middle-aged academics (57.2 years) performed a priming-recall task which was presented in three blocks. In each block, participants read 40 word pairs after which a recall task had to be carried out. Half of the word pairs were highly associated while the others were low associated. Targets showed the N400 of the middle-aged group to be both delayed and smaller in amplitude for low-associated items. N400 of primes, however, showed no age-related latency difference but was smaller for the middle-aged group due to a positive shift. It is argued that this shift possibly indicates age differences in semantic activation or buildup of context. A reanalysis showed individual differences in word pair processing to depend on recall performance. In general, high recallers were found to show a much larger differentiation between low- and high-associated targets. This resulted from a much larger N400 component elicited by low-associated targets and a more positive ERP in the N400-region for the high-associated targets. It is suggested that the middle-aged subjects activated the expected target word to a level at least equivalent to the younger subjects, but that the activated network itself was larger/less selective particularly in subjects showing a low recall.

Adult↗
PubMed2000

Parenting styles and adolescents' achievement strategies.

The aim of the study was to investigate the extent to which adolescents' achievement strategies are associated with the parenting styles they experience in their families. Three hundred and fifty-four 14-year-old adolescents completed a Strategy and Attribution Questionnaire and a family parenting style inventory. Analogous questionnaires were also completed by the adolescents' parents. Based on adolescents' report of the parenting styles, four types of families were identified: those with Authoritative, Authoritarian, Permissive, and Neglectful parenting styles. The results further showed that adolescents from authoritative families applied most adaptive achievement strategies characterized by low levels of failure expectations, task-irrelevant behaviour and passivity, and the use of self-enhancing attributions. Adolescents from neglectful families, in turn, applied maladaptive strategies characterized by high levels of task-irrelevant behaviour, passivity and a lack of self-enhancing attributions. The results provide a basis for understanding some of the processes by which parenting styles may influence adolescents' academic achievement and performance.

Achievement↗
PubMed1998

Analyte-Receptor Binding Kinetics for Biosensor Applications: A Single-Fractal and a Dual-Fractal Analysis of the Influence of the Fractal Dimension on the Binding Rate Coefficient.

The diffusion-limited binding kinetics of antigen (analyte) in solution to antibody (receptor) immobilized on a biosensor surface is analyzed within a fractal framework. Most of the data presented are adequately described by a single-fractal analysis. This was indicated by the regression analysis provided by Sigmaplot ("Scientific Graphing Procedure, User's Manual," Jandel Scientific, San Rafael, CA, 1993). A couple of examples of a dual-fractal analysis are also presented. It is of interest to note that the binding rate coefficient and the fractal dimension both exhibit changes in the same direction for the analyte-receptor systems analyzed. Binding rate coefficient expressions as a function of the fractal dimension developed for the analyte-receptor binding systems indicate the high sensitivity of the binding rate coefficient on the fractal dimension when both a single- and a dual-fractal analysis are used. For example, for a single-fractal analysis and for the binding of cell surface proteins from Helicobacter pylori strain in solution to sialyl-(alpha-2,3)-lactose-conjugated (20 mol%) polyacrylamide immobilized on a resonant mirror biosensor (S. Hirmo et al., Anal. Biochem. 257, 63, 1998), the order of dependence of the binding rate coefficient, k, on the fractal dimension, Df, was 14.15. The fractional order of dependence of the binding rate coefficient(s) on the fractal dimension(s) further reinforces the fractal nature of the system. The binding rate coefficient(s) expressions developed as a function of the fractal dimension(s) are of particular value since they provide a means to better control biosensor performance by linking it to the heterogeneity on the surface and further emphasize in a quantitative sense the importance of the nature of the surface in biosensor performance. Copyright 1998 Academic Press.

Journal Article↗
PubMed2001

A Fractal Analysis Approach for the Evaluation of Hybridization Kinetics in Biosensors.

The diffusion-limited hybridization kinetics of analyte in solution to a receptor immobilized on a biosensor or immunosensor surface is analyzed within a fractal framework. The data may be analyzed by a single- or a dual-fractal analysis. This was indicated by the regression analysis provided by Sigmaplot (Sigmaplot, Scientific Graphing Software, User's Manual, Jandel Scientific, CA, 1993). It is of interest to note that the binding rate coefficient and the fractal dimension both exhibit changes, in general, in the same direction for both the single-fractal and the dual-fractal analysis examples presented. The binding rate coefficient expression developed as a function of the analyte concentration in solution and the fractal dimension is of particular value since it provides a means to better control biosensor or immunosensor performance. Copyright 2001 Academic Press.

Journal Article↗
PubMed1997

Evidence-Based Pattern Classification: A Structural Approach to Human Perceptual Learning and Generalization

Models of human pattern classification have been traditionally based on implicit pattern descriptions which involve lists of continuous attribute values or discrete features. Here we propose an alternative approach which makes explicit use of pattern structure in terms of components and their unary (part-specific) and binary (part-relational) properties. Such attributes "evidence" different classes of patterns and allow one to model processes of both perceptual learning and generalization to novel instances. An object in an evidence-based system is represented by a set of rules, where each rule provides a certain amount of class-specific evidence. The accumulated class evidence over all activated rules determines the classification probability. We have examined how well this concept reflects human performance by training observers to classify compound Gabor patterns and then testing them with segmented (grey-level-transformed) versions of the patterns in the original training set. If the observers were to construct rules to define each pattern class in terms of perceived parts and their relations, then it should be expected that classification performance would generalize to these new patterns. Results confirm this hypothesis and the specific feature extraction, learning, and rule generation model used to predict performance. Copyright 1997 Academic Press

Journal Article↗
PubMed2000

Nuclear magnetic resonance in inhomogeneous magnetic fields

The response of the spin system has been investigated by numerical simulations in the case of a nuclear magnetic resonance (NMR) experiment performed in inhomogeneous static and radiofrequency fields. The particular case of the NMR-MOUSE was considered. The static field and the component of the radiofrequency field perpendicular to the static field were evaluated as well as the spatial distribution of the maximum NMR signal detected by the surface coil. The NMR response to various pulse sequences was evaluated numerically for the case of an ensemble of isolated spins (1/2). The behavior of the echo train in Carr-Purcell-like pulse sequences used for measurements of transverse relaxation and self-diffusion was simulated and compared with the experiment. The echo train is shown to behave qualitatively differently depending on the particular phase schemes used in these pulse sequences. Different echo trains are obtained, because of the different superposition of Hahn and stimulated echoes forming mixed echoes as a result of the spatial distribution of pulse flip angles. The superposition of Hahn and stimulated echoes originating from different spatial regions leads to distortions of the mixed echoes in intensity, shape, and phase. The volume selection produced by Carr-Purcell-like pulse sequences is also investigated for the NMR-MOUSE. The developed numerical simulation procedure is useful for understanding a variety of experiments performed with the NMR-MOUSE and for improving its performance. Copyright 2000 Academic Press.

Journal Article↗
PubMed1998

New High-Resolution Analysis of the nu3, nu4, and nu6 Bands of D2CO Measured by Fourier Transform Spectroscopy

A reanalysis of the nu3, nu4, and nu6 interacting bands of D2CO has been carried out in the region 850-1250 cm-1 using high-resolution Fourier transform spectra recorded at Giessen. As compared to the previous study of these bands (1987, K. Nakagawa, R. H. Schwendeman, and J. W. C. Johns, J. Mol. Spectrosc. 122, 462-476) higher J and Ka transitions were assigned for the three bands, leading to a better determination of the upper state constants. The v3 = 1, v4 = 1, and v6 = 1 experimental energy levels were introduced in a least-squares fit calculation together with the microwave measurements available in the literature in order to obtain the upper state parameters (band centers, rotational and coupling constants). In this calculation, which allowed us to reproduce both the infrared and the microwave measurements to within their experimental accuracies, the A-, B-, and C-type Coriolis interactions involving the rotational levels belonging to the v4 = 1 and v6 = 1, v3 = 1 and v4 = 1, and v3 = 1 and v6 = 1 interacting states respectively were explicitly taken into account. Finally, from the intensities, a new determination of the relative values of the q3, q4, and q6 first derivatives of the D2CO dipole moment was performed. Copyright 1998 Academic Press. Copyright 1998Academic Press

Journal Article↗
PubMed1998

Fourier Transform Emission Spectroscopy of the A2Pi-X2Sigma+ Transition of BeD.

The A2Pi-X2Sigma+ Deltav = 0 sequence of BeD was observed in the 19 500-20 800 cm-1 spectral region using a Fourier transform spectrometer. The emission spectrum was excited in a Be hollow cathode discharge lamp with a He/D2 gas mixture. The observed lines were assigned to the 0-0 to 6-6 bands. The Deltav = -1 sequence was too weak to be seen in our Fourier transform spectra. We therefore used a previously recorded but unpublished arc emission spectrum to identify the 0-1 to 5-6 Deltav = -1 bands. Consequently, all of the diagonal bands could be linked together and the vibrational intervals determined. The Deltav = 0 and Deltav = -1 data were fitted together in a global fit and effective constants derived. Using the information available from the study of the C2Sigma+-X2Sigma+ system [R. Colin, C. Drèze, and M. Steinhauer, Can. J. Phys. 61, 641 (1983)], the v = 8-12 vibrational levels of the ground state were added in a Dunham fit. A set of Dunham Y constants was determined for the X2Sigma+ state along with traditional equilibrium parameters for the A2Pi excited state. The equilibrium bond lengths were found to be 1.341742(5) Å for the ground state and 1.33309(4) Å for the excited state. A reanalysis of the previously published A2Pi-X2Sigma+ 0-0 to 3-3 Deltav = 0 bands of BeT [D. De Greef and R. Colin, J. Mol. Spectrosc. 53, 455-465 (1974)] was also performed. Copyright 1998 Academic Press.

Journal Article↗
PubMed1999

Blissful Ignorance? Departure Rules for Migrants in a Spatially Heterogeneous Environment.

Incomplete knowledge of the variation in site quality to be encountered during migration may make it necessary for birds to base their departure decisions on behavioural rules of thumb. Here I analyse four such rules for time-minimizers and show how they perform in spatially heterogeneous, autocorrelated environments. The first rule projects the currently experienced fuelling rate onto all the future sites, the second rule is based on a fixed expected rate along the route, the third rule assumes that the expected rate at sites nearby is close to the value currently experienced and the fourth rule uses the experienced values to form an expectation during migration. Simulations demonstrate that a global update rule which uses the current experience and interprets it as the global value to be expected at all the future sites is outperforming the second rule, which is based on fixed expectations, in nearly all circumstances and that it is very robust with respect to spatial autocorrelation and the degree of variability in fuelling rates. This rule leads to the repeatedly observed pattern of a shallow relationship between departure fuel load and fuel deposition rate. A third rule shows its best performance under the assumption that the quality of sites only changes little with distance and therefore comes close to the global update rule. The fourth departure rule, a modified version of the global update rule, which allows some adjustments of the expected value through all the experienced values so far, leads only to small increases in performance. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Collective Induction: Twelve Postulates.

Collective induction is the cooperative search for descriptive, predictive, and explanatory generalizations, rules, and principles. This article presents 12 postulates on collective induction and supportive evidence for the postulates. Postulates 1-6 set collective induction within the general social combination approach to cooperative group decision making. Postulates 7 and 8 formalize the social combination processes of group hypothesis formation in collective induction. Postulates 9-12 summarize research on collective versus individual induction, the relative importance of multiple hypotheses and multiple evidence, influence in simultaneous collective and individual induction, and the relative effectiveness of positive and negative hypothesis tests. We then consider the history and fundamental emphasis of the social combination approach to small group performance. Copyright 1999 Academic Press.

Journal Article↗
PubMed1993

The self-perceptions and attributions of attention deficit hyperactivity disordered and nonreferred boys.

Compared the self perceptions and attributions of attention deficit hyperactivity disordered (ADHD) and control boys. The ADHD boys viewed themselves as no worse than control boys on self-perceived competence and global self-worth, especially when internalizing symptomatology was taken into account statistically through covariance analyses. In terms of attributions, the ADHD boys were more likely to take responsibility for social successes and less likely to take responsibility for social failures than the control boys. Although the ADHD boys scored significantly higher on the Children's Depression Inventory, this difference was no longer significant when items dealing with behavior, school, and social problems were excluded. The results are discussed in terms of their implications for understanding how the attributions and self-perceptions of ADHD boys may mediate their performance in challenging academic and social situations.

Adolescent↗
PubMed1993

Contribution to scientific research in paediatrics in The Netherlands: evaluation according to subspeciality over a 10-year period.

The board of the Dutch Paediatric Association requested a survey of the scientific research performed in all academic and non-academic paediatric hospitals, authorized to train medical doctors in paediatrics in the Netherlands. Contributions to the international and the Dutch scientific literature, in the form of regular publications, chapters in books, contributions to proceedings and Ph.D. theses were counted over two 5-year periods, i.e. 1981-1985 and 1986-1990. The quality of publications in the international journals was assessed using the average impact factor of the journals over the 10-year period. The number of publications in the international literature doubled during the observation period 1986-1990 compared to the period 1981-1985. Nevertheless, the quality of the publications remained the same. Metabolism, oncology/haematology, immunology/infectious diseases and cardiology are the subspecializations in which scientific research takes place in four or more academic paediatric hospitals. In total, 84 Ph.D. theses were produced in which a paediatrician was either the project leader (mostly a professor in paediatrics) or the investigator-in-charge. Insight into structure and major research efforts of paediatric hospitals in other countries of Europe may lead to exchange of views and, maybe, profitable co-operation.

Netherlands↗
PubMed1993

Screening flexible sigmoidoscopy: patient attitudes and compliance.

OBJECTIVE: To measure patients' expectations and attitudes about screening flexible sigmoidoscopy and their discomfort during the procedure, and to identify factors affecting compliance among patients scheduled for sigmoidoscopy. DESIGN: Patient survey at the time sigmoidoscopy was ordered and again one week after the procedure was performed. SETTING: An academic general internal medicine practice. PATIENTS: 105 consecutive patients scheduled for screening flexible sigmoidoscopy. MAIN RESULTS: Seventy-five percent of patients (79/105) scheduled for sigmoidoscopy complied with the procedure. Compliance was higher among men and among patients who had family histories of colon cancer. Although many patients experienced moderate to extreme embarrassment (27%), discomfort (42%), and pain (31%), patients experienced less embarrassment (p = 0.03) and pain (p = 0.02) than they had expected. Patients aged 65 years and older were twice as likely as younger ones (52% versus 25%) to experience moderate to extreme pain (p = 0.04). Only 1.4% of patients reported that they would probably not have the test again. CONCLUSION: Although flexible sigmoidoscopy is an uncomfortable procedure for some patients, especially those aged 65 and older, in general it is not as bad as patients expect and most would have the test again. Therefore, rather than assuming sigmoidoscopy is too uncomfortable for all patients to tolerate as a screening test, clinicians should inform their patients about the potential benefits and risks of sigmoidoscopy and about what the patient can expect during the procedure, thus enabling the patient to make an informed decision about whether to undergo screening sigmoidoscopy.

Aged↗