1,696 research outputs found
Are language production problems apparent in adults who no longer meet diagnostic criteria for attention-deficit/hyperactivity disorder?
No full textIn this study, we examined sentence production in a sample of adults (N = 21) who had had attention-deficit/hyperactivity disorder (ADHD) as children, but as adults no longer met DSM-IV diagnostic criteria (APA, 2000). This “remitted” group was assessed on a sentence production task. On each trial, participants saw two objects and a verb. Their task was to construct a sentence using the objects as arguments of the verb. Results showed more ungrammatical and disfluent utterances with one particular type of verb (i.e., participle). In a second set of analyses, we compared the remitted group to both control participants and a “persistent” group, who had ADHD as children and as adults. Results showed that remitters were more likely to produce ungrammatical utterances and to make repair disfluencies compared to controls, and they patterned more similarly to ADHD participants. Conclusions focus on language output in remitted ADHD, and the role of executive functions in language production
Influence of methylphenidate on brain development--an update of recent animal experiments.
No full textGrund T, Lehmann K, Bock N, Rothenberger A, Teuchert-Noodt G. Influence of methylphenidate on brain development--an update of recent animal experiments. Behav Brain Funct. 2006;2(1): 2.Methylphenidate (MPH) is the most commonly used drug to treat attention deficit/hyperactivity disorder (ADHD) in children effectively and safely. In spite of its widespread application throughout one of the most plastic and sensitive phases of brain development, very little is known to date about its long-term effects on brain structure and function. Hence, this short review updates the influence of MPH on brain development, since recent human and animal studies suggest that MPH alters the dopaminergic system with long-term effects beyond the termination of treatment.Animal studies imply that the effects of MPH may depend on the neural responder system: Whereas structural and functional parameters are improved by MPH in animals with psychomotor impairments, they remain unaltered or get worse in healthy controls. While recent behavioural studies do not fully support such a differential effect of MPH in ADHD, the animal studies certainly prompt for further investigation of this issue. Furthermore, the abuse of MPH, when (rarely) intravenously applied, may even impair the maturation of dopaminergic fibres in subcortical brain areas. This argues for careful clinical assessment and diagnostics of ADHD symptomatology not only in conjunction with the prescription of MPH. Hence, one should be assured that MPH is only given to children with clear ADHD symptomatology leading to psychosocial impairment. The animal data suggest that under these conditions MPH is supportive for brain development and the related behaviour in children with ADHD
Generalized TASE-RK methods for stiff problems
No full textA family of Time-Accurate and Stable Explicit (TASE) methods for the numerical integration of Initial Value Problems in stiff Ordinary Differential Equations (ODEs) y'(t) = f (t, y) was recently introduced in [1]. The main idea was to make local extrapolation of a stabilized Euler method. More recently, in [3] a similar approach by considering the stabilization of arbitrary explicit Runge-Kutta methods (TASE-RK) was analyzed. In this case the explicit Runge-Kutta method integrates a transformed ODE obtained by multiplying the vector field f (t, y) by a certain operator which approximates the identity mapping up to a given order p. The main inconvenience of both approaches is that to reach order p the solution of p2 linear systems plus the evaluation of p derivatives are required per integration step.In order to substantially reduce the computational costs of the former approaches in the linear system solution, but maintaining the good accuracy and stability properties, a new family of TASE-RK methods which allow to introduce a few more free parameters are considered. The formulation of the methods was conceived to be implemented not only in sequential mode but it admits parallelism in a straightforward way. Furthermore, since these methods are linearly implicit, connections to the class of W-methods [19] are properly established. The order conditions for the new class of methods are widely studied by using the rooted tree theory. For p = 3, 4, new methods with p sequential stages and order p are derived and compared on semidiscrete 1D and 2D Partial Differential Equations (PDEs) to those in [1,3] and other standard Rosenbrock and W-methods in the literature.(c) 2023 The Author(s). Published by Elsevier B.V. on behalf of IMACS. This is an open access article under the CC BY-NC-ND license (http:// creativecommons .org /licenses /by-nc -nd /4 .0/)
Three-dimensional imaging in orthognathic surgery: the clinical application of a new method
No full textMany 3-dimensional (3D) techniques have been utilized to register and analyze the face in 3 dimensions, but each system has its own merits and disadvantages. C3D is a relatively new 3D imaging system that was developed to capture the 3D geometry of the face. Landmark identification on 3D facial models is facilitated by a software-based facial analysis tool developed by the authors. The reproducibility of landmark identification was high for 20 of the chosen points (standard deviations of repeated placements of landmarks around their centroids were 0.5 mm or less). The method is useful in studying facial soft tissue changes following orthognathic surgery and other types of facial surgery, as well as assessing facial soft tissue growth and development of the craniofacial comple
The morphological effects of sediment diversions the Lower Mississippi River
No full textThe wetlands in the Mississippi delta (USA) are drastically subsiding and eroding. Many projects and researches are ongoing to determine how this “drowning effect” of the delta can be stopped. One of the solutions that could be feasible is implementing sediment diversions in the levees of the Lower Mississippi River in order to divert sediment into the delta. This thesis addresses the morphological effects of river diversions on the Lower Mississippi River. The main objective is to analyze and optimize trade-offs between delta building and river navigability. For this purpose a 2DH numerical model with Delf3D has been created; the model simulates the hydro- and morphodynamic behavior. The river reach which has been studied is the final 110 km of the river from Point a la Hache at River Kilometer 78 (RK 78) down to the mouth of the river (RK -30), below Head of Passes. The hydrodynamic model has been calibrated and verified with flow and stage data from daily observations on the river. With the available sediment data a calibration has been carried out of the morphological behavior in the river. The model has been used to simulate several scenarios to get insight in the problems in the delta. From analysis of the model results the river bed in the study area can be divided into three categories. Upstream of RK 4 the bed is subject to erosion, around RK 4 the bed is practically in equilibrium and downstream of RK 4 the bed is subject to sedimentation. The reach downstream of RK 4 is the dredging reach; after analyzing the long-term simulation of 20 years it is not expected that the dredging quantities will decrease in the future. Closing off West Bay diversion has a positive effect on the dredging quantities. The best diversion site for this study area is found in the inner bend of the river upstream of Empire (RK 47) at RK 53. This site is most efficient and diverts the largest quantities of sand through the diversion.Hydraulic EngineeringCivil Engineering and Geoscience
Facial asymmetry-3D assessment of infants with cleft lip and palate
No full textOBJECTIVES: To determine the degree of facial asymmetry in infants with unilateral cleft lip and/or palate, and quantify improvements following primary surgery, in three dimensions. DESIGN: The faces of 20 infants with unilateral clefts (10 UCL; 10 UCLP), and 20 age-matched, non-cleft controls, were captured using the C3D (TM) stereophotogrammetry system prior to primary lip/nose repair (at 3 months), at 6 months and at age 1 year. METHODS: Procrustes techniques were applied to 3D landmark configurations to its mirror image. Mean squared distances between landmarks and their antimeres were calculated and expressed as asymmetry scores for each 3D configuration. Full-face, nose and lip median scores were compared and changes with time evaluated (P < 0.01). RESULTS: There were no significant changes in asymmetry scores in the control group from 3 months to 1 year. The UCLP group was more asymmetric than the UCL group, displaying greatest improvement in nasal symmetry following primary repair. The lips continued to improve over time. The UCL group had significant nasal asymmetry, which did not appear to improve with primary surgery. CONCLUSIONS: Immediate improvement in asymmetry scores in children with UCLP is related to the production of a more symmetrical nasal form after primary surgery. In contrast, the nasal asymmetry seen in children with UCL is unchanged despite surgery. Full face asymmetry scores may mask subtle changes over time. Nasal and lip asymmetry should be considered individually
The Dunston Manuscript
No full textVariously titled 80 Slides and a Memory, Fit for a King and others this is the definitive performed version as an invited reading in 2001 to the Urban Design Group. It describes in blank verse the early stages of the Gateshead Garden Festival illustrated with slide
Facial characterization of infants with cleft lip and palate using a three-dimensional capture technique
No full textObjective: To characterize the soft tissue features of infants with unilateral cleft lip (UCL) and unilateral complete cleft lip and palate (UCLP) prior to primary surgery and compare with noncleft controls.
Design: Prospective controlled capture of the facial morphology of infants using a noninvasive three-dimensional stereophotogrammetry method.
Participants: 23 children with presurgical cleft: 11 UCL (M = 6, F = 5); 12 UCLP (M = 9, F = 3), and 21 noncleft controls (M = 7, F = 14) were imaged at approximately 3 months of age (range 10 to 16 weeks).
Main Outcome Measure: Accurate, repeatable quantification of facial soft tissues in infants with clefts prior to surgery.
Results: Significant differences (p < .05) were found between the UCLP group and UCL and control groups in anatomical and soft nose width, cleft-side alar wing length, and nasal tip horizontal displacement. Both cleft groups were significantly different from controls and from each other in cleft-side nostril dimensions, alar wing angulation, columella angle, and alar base to corner of mouth dimension; alar base width; and soft tissue defect in nose and the lip and philtrum length bordering the cleft. Significant differences between clefts and controls were identified in the nostril and philtrum on the noncleft side.
Conclusions: The use of children with UCL as controls for UCLP studies is inappropriate. This technique overcame the limitations of direct measurement of infant faces to aid the surgeon in the planning and subsequent re-evaluation of surgical rationale
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