The development of hand-mouth coordination in early infancy

The aim of the thesis is to offer a comprehensive account of the developmental course of hand-mouth (HM) coordination from birth until a mature form of the coordination is attained. Questions relating both to the structure and function of the coordination were addressed. Three studies are reported. The method of observation was the same in each case; video records of two perpendicular views of the infant were obtained and a micro-analysis of movement structure was carried out. The main question addressed in study 1 was whether spontaneous HM contacts in newborns are related to hunger. HM contacts were compared before and after feeding in a group of newborn babies. There was no change in the relative distribution of locations of contacts on the mouth and face before and after feeding, but anticipatory mouth opening prior to HM contacts only occurred before feeding. Study 2 sought to obtain detailed measures of transitions taking place between 1-5 months in the structure of HM coordination, and to investigate what factors could be responsible for the changes observed. A longitudinal design was employed where babies were observed at monthly intervals. A small object was placed in the hands of infants to promote oral contacts. At 4 months of age, contacts began to be centred on the mouth (as opposed to other parts of the face) and the frequency of contacts was significantly higher when the object was present relative to the frequency of spontaneous contacts. Anticipatory mouth opening only occurred at 5 months of age, suggesting that this aspect of the coordination follows a U-shaped developmental trajectory. There was evidence that vision was playing a role in motivating HM contacts by 5 months of age. Consistent individual differences between babies were found in different aspects of HM coordination raising the possibility that more than one developmental route is followed in the achievement of mature HM coordination. Study 3 investigated HM coordination cross-sectionally between the ages of 5-9 months. The possibility that the development of reaching was influencing the development of HM coordination was investigated. Two situations were compared, one where the infant had to reach for an object prior to transportation to the mouth and another where the object was placed in the hand of the infant. Although HM coordination and reaching and grasping were already integrated at 5 months, the two coordinations appear to develop independently of each other. The development of HM coordination was found to be marked by motivational and structural shifts and apparent regressions. The results are interpreted within a dynamic systems view of development

Aortic Wave Dynamics and Its Influence on Left Ventricular Workload

The pumping mechanism of the heart is pulsatile, so the heart generates pulsatile flow that enters into the compliant aorta in the form of pressure and flow waves. We hypothesized that there exists a specific heart rate at which the external left ventricular (LV) power is minimized. To test this hypothesis, we used a computational model to explore the effects of heart rate (HR) and aortic rigidity on left ventricular (LV) power requirement. While both mean and pulsatile parts of the pressure play an important role in LV power requirement elevation, at higher rigidities the effect of pulsatility becomes more dominant. For any given aortic rigidity, there exists an optimum HR that minimizes the LV power requirement at a given cardiac output. The optimum HR shifts to higher values as the aorta becomes more rigid. To conclude, there is an optimum condition for aortic waves that minimizes the LV pulsatile load and consequently the total LV workload

Computational studies of resonance wave pumping in compliant tubes

The valveless impedance pump is a simple design that allows the producion or amplification of a flow without the requirement for valves or impellers. It is based on fluid-filled flexible tubing, connected to tubing of different impedances. Pumping is achieved by a periodic excitation at an off-centre position relative to the tube ends. This paper presents a comprehensive study of the fluid and structural dynamics in an impedance pump model using numerical simulations. An axisymmetric finite-element model of both the fluid and solid domains is used with direct coupling at the interface. By examining a wide range of parameters, the pump's resonance nature is described and the concept of resonance wave pumping is discussed. The main driving mechanism of the flow in the tube is the reflection of waves at the tube boundary and the wave dynamics in the passive tube. This concept is supported by three different analyses: (i) time-dependent pressure and flow wave dynamics along the tube, (ii) calculations of pressure–flow loop areas along the passive tube for a description of energy conversion, and (iii) an integral description of total work done by the pump on the fluid. It is shown that at some frequencies, the energy given to the system by the excitation is converted by the elastic tube to kinetic energy at the tube outlet, resulting in an efficient pumping mechanism and thus significantly higher flow rate. It is also shown that pumping can be achieved with any impedance mismatch at one boundary and that the outlet configuration does not necessarily need to be a tube

Simulation of sheet-titanium forming of welded blanks

The increase in demand for the light and tough drawn-parts causes the growing interest in sheet metal forming of Tailor-Welded Blanks (TWB). Application of such blanks allows for achieving in one operation the drawn-parts characterized by diverse strength and functional properties. It also allows for reduction of material waste and decrease in number of parts needed to produce component. Weight reduction is especially important for the car and aircraft industry. Forming welded blanks requires solving many problems such as different plasticity of the joined materials, presence of the weld and its dislocation. In order to evaluate suitability of welded blanks for the forming processes, it is necessary to carry out several studies, including numerical simulations of the process, that will allow for prediction of sheet behaviour in consecutive forming stages. Although to date aluminium and steel TWBs are mainly used, the aircraft industry is also interested in application of titanium TWBs. Generally sheet-titanium forming is more difficult than steel or aluminium sheets. The weld presence complicates the forming process additionally. In the paper some numerical simulation results of sheet-titanium forming of welded blanks will be presented. Forming the spherical caps from the uniform and welded blanks will be analysed. Grade 2 and Grade 5 (Ti6Al4V) titanium sheets with thickness of 0.8 mm will be examined. A three-dimensional model of the forming process and numerical simulation will be performed using the ADINA System v.8.6, based on the finite element method (FEM). An analysis of the mechanical properties and geometrical parameters of the weld and heat affected zone (HAZ) are based on the experimental studies. Drawability and possibilities of plastic deformation will be assessed basing on the comparative analysis of the determined plastic strain distributions in the drawn-parts material and thickness changes of the drawn-part wall. The results obtained in the numerical simulations will provide important information about the process course. They will be useful in design and optimization of the forming process

Numerical and experimental analysis of cold forming of titanium alloy sheets

Due to an increasing demand for the titanium drawn-parts, mainly from the aerospace and car industries, the demand for expertise in sheet-titanium forming grows. Although titanium combine many valuable features like lightweight with high strength and excellent corrosion resistance, its application is still limited because titanium processing, especially cold forming of titanium sheets poses many problems. In the paper technological problems with forming of titanium sheets is discussed. A special attention is paid to flexible forming. The experimental and numerical simulation results of semi-flexible forming are presented. The numerical analyses are carried out with the ADINA System v. 8.6 basing on the Finite Element Method (FEM). A spherical drawn-part made of Ti6Al4V titanium sheet is analysed. The material data, which are necessary for the numerical calculations, such as tensile strength Rm, yield point Re, R-value and hardening coefficient n were determined experimentally. The numerical calculations show good convergence with the experiment

A new experimental snow avalanche test site at Seehore peak in Aosta Valley (NW Italian Alps) - Part II: Engineering aspects

The estimate of the effects produced by the impact of a snow avalanche against an obstacle is of the utmost importance in designing safe mountain constructions. For this purpose, an ad-hoc instrumented obstacle was designed and built in order to measure impact forces of small and medium snow avalanches at Seehore peak (NW Italian Alps). The structural design had to consider several specific and unusual demands dictated by the difficult environment. In this article, the new test facility is described from the engineering point of view, discussing the most important aspects of the analyzed problems which were solved before and after the construction. The performance of the instrumented obstacle in the first two operating seasons, and some proposals for future upgrading are eventually illustrate

"A Program of Opera Scenes," November 8, 9, 1985

This is the concert program of the "A Program of Opera Scenes" performance on Friday, November 8, and Saturday, November 9, 1985, at the Concert Hall, 855 Commonwealth Avenue. Scenes performed were Act II, scene 2 from The Merry Wives of Windsor by Otto Nicolai, Act II, scenes 1 and 2 from Hansel and Gretel by Engelbert Humperdinck, Act I Duet from L'Elisir D'Amore by Gaetano Donizetti, Act II, scene 2 from The Rake's Progress by Igor Stravinsky, with libretto by W. H. Auden and Chester Kallman, Act II Quintet from Carmen by Georges Bizet, with libretto by H. Meilhac and L. Halevy, Act III from La Bohème by Giacomo Puccini, with libretto by G. Giacosa and L. Illica, and Act I finale from Così fan tutte by Wolfgang Amadeus Mozart, with libretto by Lorenzo Da Ponte. Digitization for Boston University Concert Programs was supported by the Boston University Humanities Library Endowed Fund

Fabric-formed concrete member design

This paper introduces engineering design and analytical modeling techniques providing the design community with an alternative means for forming concrete structures by using flexible fabric formwork

Social cognition in children with epilepsy in mainstream education

AIM To establish whether deficits in social cognition are present in children with generalised or focal epilepsy in mainstream education, and whether any relation exists between social cognition, communication, and behaviour measures. METHOD In a cross-sectional study, children with an epilepsy-only diagnoses in mainstream education (n=20 with generalized epilepsy; eight males, 12 females; mean age 11y 6mo, SD 2y 6mo; and n=27 with focal epilepsy; 12 males, 15 females; mean age 11y 8mo, SD 2y 2mo) and comparison participants (n=57; 28 males, 29 females; mean age 11y 2mo, SD 2y 4mo) were administered the Strange Stories task and the Mind in the Eyes task, as well as an IQ assessment. Parents completed the Children’s Communication Checklist-2 and the Child Behavior Checklist (CBCL). RESULTS Both groups of children with epilepsy performed more poorly than control children on the Mental Stories component of the Strange Stories task, F(2,101)=3.2, p<0.001. Performance on Mental Stories was related to pragmatic communication, but only in the generalized epilepsy group (r=0.51, p=0.03, 95% CI=0.2–0.8). There were no differences between epilepsy groups or control participants in the Mind in the Eyes task, F(2,101)=0.4, p=0.4. INTERPRETATION Children with ‘epilepsy only’ are at risk of deficits in social cognition and may require appropriate support