This study involved a 28-week school-based exercise trial of single-leg drop-landing exercise with 42 girls (Tanner stage 1; 6-10 yr old) randomly assigned to control (C), low-drop (LD) or high-drop(HD) exercise groups. The latter two groups performed single-leg drop-landings (3 sessions.wk-1 and 50 landings.session-1) from 14cm and 28cm, respectively using the non-dominant leg. Single-leg peak ground-reaction impact forces (PGRIF) in a sub-sample ranged between 2.5 – 4.4 x body-weight (BW). No differences (p>0.05) among groups at baseline for age, stature, lean tissue mass (LTM - DXA - Lunar 3.6-DPX), leisure time physical activity or average daily calcium intake were detected. No significant within group changes for between leg differences from baseline to post-training and no significant differences among groups at baseline, or in magnitude of change for any of the dominant or non-dominant (loaded) leg bone mineral content (BMC g) measures determined by DXA – loaded leg total - 19.06, 25.5, 25.46 [p=.156], femoral neck - 0.14, 0.11, 0.15 [p=.959], greater trochanter - 0.37, 0.06, 0.26 [p=.733], mid femoral shaft - 3.87, 3.87, 3.42 [p=.677] for the C, LD and HD groups, respectively, after adjusting for the covariates baseline body and fat mass, and change in LTM (ANCOVA) were observed. Similarly, following ANCOVA adjustments no significant differences for changes in calcaneal speed of sound and broadband ultrasound attenuation (CUBA Clinical), DXA derived changes in femoral neck (-0.009, 0.033, -0.009; p=.189) and total MFS (0.029, 0.041, 0.053; p=.447) volumetric BMD (g.cm-3), or MFS cortical volumetric BMD, the latter derived by a new technique combining MRI and DXA were identified. TBBMC changed by 79.6g-C, 100.2g-LD and 91.9g-HD (p=.339). Combining data from both exercise groups to increase statistical power produced similar results. No significant within group changes for between leg differences from baseline to post-training and no significant differences among groups at baseline, or in magnitude of change for any of the dominant or non-dominant (loaded) leg bone geometrical (area cm2) determined by MRI using ANALYZE® software of proximal - 22.18, 12.91, 19.86 [p=.248], mid - 19.83, 15.91, 19.64 [p=.233], or distal - 14.78, 16.07, 13.35 [p=.792], slice cortical area for the C, LD and HD groups, respectively, after adjusting for the covariates baseline body and fat mass, and change in LTM (ANCOVA) were detected. Similarly there were no significant biomechanical cross sectional moment of inertia (CSMI cm4) changes determined by Scion Image® (Frederick, Maryland: Version-Beta 3B) and a custom macro program of proximal - 896, 815, 649 [p=.415], mid - 1054, 806, 1087 [p=.471], or distal - 1197, 1079, 966 [p=.606], slice CSMI for the C, LD and HD groups, respectively after adjusting for the same covariates. In contrast to some recent reports, our findings suggest that strictly controlled uni-modal; uni-directional single-leg drop-landing exercises involving low-moderate peak ground-reaction impact forces are not osteogenic in the developing prepubertal female skeleton.

根據研究資料分析後，本研究所獲致的結論如下所述：一、造成犯罪青少年中途輟學原因方面：在家庭問題上，有中途輟學經驗犯罪青少年比沒有中途輟學經驗的犯罪青少年較不喜歡待在家中，也覺得父母親對他們不了解，所以遇到問題不會與父母親討論；在學校問題方面，犯罪青少年多數認為老師對他們的印象不好，這些青少年對老師的印象也不好，他們與同班同學相處不佳，也不喜歡學校；而在個人問題上，這些有輟學經驗的犯罪青少年結交較多前科記錄的朋友，並且對自己較為缺乏信心，並且角色能力較差；最後在行為模式方面，有輟學經驗的犯罪青少年大都喜歡曠課、蹺課到校外遊蕩，而且多數在學校的操行分數不及格，並被學校以記過處分。為何有這種情形發生呢？歸咎其原因總共有三點：第一，主要是由於學業成績不佳。第二，同儕團體也會在這方面有所影響。第三，自我實現預言的作用。二、中途輟學與青少年犯罪的關係：中途輟學的發生究竟會不會影響日後參予犯罪行為呢？在探討本研究最為重要的研究目的時，問卷的結果顯示，在犯罪青少年的樣本中，65%的人有過輟學經驗，在經由個案訪談後發現，有過中途輟學經驗的受訪個案中，90%的人對是否中途輟學會影響犯罪表示贊同，所以可以了解到，中途輟學確實與犯罪行為的參予有關係存在。那麼，為何中途輟學具有影響力呢？經由個案訪談後歸納出三個主要原因：（一）、受到不良同儕團體的影響；（二）、未就業的影響；（三）缺乏自我控制的能力。所以可知，本研究結果顯示，中途輟學與青少年參予犯罪行為間確實有關係存在，所以也可說明，社會控制論的觀點是正確的，也就是學校為重要的社會控制機構，如果脫離與此控制機構的連帶，青少年很容易便會產生偏差或是犯罪的行為。所以為了要預防青少年犯罪，如果能減少青少年中途輟學的發生，相信青少年犯罪機率定會減少許多。

Concrete is the most broadly used material in construction worldwide and Reactive Powder Concrete (RPC, a type of ultra high performance concrete) is a relatively new member of the concrete family. In this work the critical parameters of RPC mix design are investigated and the mix design is explored through a program of concrete casting and testing. Owing to the enhanced microstructure of RPC, porosity and permeability can be significantly decreased in the concrete matrix. This benefits the durability characteristics of RPC elements resulting in a longer service life with less maintenance costs than conventional concrete. It has been used for high integrity radiation waste material containers because of its low permeability and durability. Fibre reinforced RPC is also ideal for use in long span and thin shell structural elements without traditional reinforcement because of its advantageous flexural strength. Moreover, due to improved impact resistance, RPC can be widely employed in piers of bridges, military construction and blast protection. There is no standard approach to assessing the impact resistance of concrete. This investigation utilises relatively well accepted impact equipment to evaluate the mechanical properties of RPC under dynamic loading. The compressive and flexural tensile strengths of plain and fibre reinforced RPC are investigated using a variety of specimens and apparatus. The dynamic increase factor (DIF) is evaluated to indicate the strain rate sensitivity of the compressive and flexural strength.

<p><!-- @page { size: 8.5in 11in; margin: 0.79in } P { margin-bottom: 0.08in } --></p><p>Free fall drop testing is an important part of the development of commercial electronic components and devices. In the process of optimizing the quality of their entire product range, Sony Ericsson Mobile Communications AB have decided to review their free fall drop test equipment with the goal of increasing the precision, repeatability, and time efficiency of their drop test applications. In regard to the free fall drop test principle a robot system with management software, named Doris Drop Test System, is developed to meet these goals.</p><p>As the amount of related work for this application is as minimal as the timeframes for this project, the development process is empirical and entrepreneurial with engineering skills as the governing line of work. Combining the competence from fields such as mechanics, electronics and product development, reaching the goals is successful enabling the identifying of two different drop methods – Impact Position and Drop Position. Increasing the repeatability from approximately 10% to 85% enables anyone at any time to perform the exact mobile phone drop test. By reaching a precision of up to 100%, performing free fall drop tests aiming for testing specific mobile phone parts, optimizes the development process by faster detection of mechanical weaknesses. Achieving these results in parallel with increasing the throughput by shortening the testing time, has proven the success of the Doris Drop Test System.</p><p> </p>

<p>This study investigates a new interaction technique for collaboration on handheld computers called Pick-and-Drop. The technique is an extension of the popular Drag-and-Drop method used in many graphical interfaces today, but with Pick-and-Drop on-screen objects can be picked from one screen with a pen and dropped onto another. </p><p>The aim of the study is to answer whether Pick-and-Drop promote collaboration among children by letting them focus more on other users and the task at hand than on the computer interaction. The study also investigates in what way collaborative situations can benefit from Pick-and-Drop. </p><p>A prototype Pick-and-Drop system was implemented on four customized handheld computers equipped with wireless network communication. The prototype allowed spontaneous collaboration using ad-hoc networks and peer-to-peer communication. Radio Frequency Identification (RFID) tags were used to identify the pens when picking and dropping objects from the screen. </p><p>Ten children aged 6-7 years old participated in the study at an after- school recreational centre. They tried Pick-and-Drop by playing a collaborative game of buying and selling apples using golden coins represented as icons on the screen. The test was video filmed for later analysis. </p><p>The study showed that Pick-and-Drop offers effective collaborative interaction based on a mix of turn taking and concurrent interaction. Users do not have to switch focus when using an application or sharing data as the interaction style stays the same. There was an interesting difference in control over the interaction when users shared objects by “giving” or by “taking”. Users stayed in better control when they shared objects through giving.</p>

This study describes the strength, toughness and strain-rate sensitivity of fibre-reinforced cement-based foams subjected to variable loading rates. Drop-weight impact tests were conducted on beams with cast density between 475 - 1200 kg/cu.m. The study shows that under quasi-static loading, the compressive strength, elastic modulus and the modulus of rupture of plain mixes scale with the square of the relative density. On the other hand, the flexural toughness factor scaled linearly with it. Fibres were seen to increase the flexural strength at all rates of loading, regardless of cast density. Further, cement based foams were seen to be strain-rate sensitive. The resistance of cement-based foams to sulphate exposure was also investigated. Heavier cement-based foams are more susceptible to sulphate attack and perform poorly with an increase in the duration of exposure when compared to the lightest mix which showed improved responses up to 30 days of exposure due to self-healing. / Structural Engineering

Digital computers have changed human society in a profound way over the last 50 years. Key properties that contribute to the success of the computer are flexible programmability and fast access to large amounts of data and instructions. Effective access to algorithms and data is a fundamental property that limits the capabilities of computer systems. For PC computers, the main memory consists of dynamic random access memory (DRAM). Communication between memory and processor has traditionally been performed over a multi-drop bus. Signal frequencies on these buses have gradually increased in order to keep up with the progress in integrated circuit data processing capabilities. Increased signal frequencies have exposed the inherent signal degradation effects of a multidrop bus structure. As of today, the main approach to tackle these effects has been to reduce the number of endpoints of the bus structure. Though improvements in DRAM memory technology have increased the available memory size at each endpoint, the increase has not been able to fully fulfill the demand for larger system memory capacity. Different bus structural changes have been used to overcome this problem. All are different compromises between access latency, data transmission capacity, memory capacity, and implementation costs. In this thesis we focus on using the signal processing capabilities of a modern integrated circuit technology as an alternative to bus structural changes. This has the potential to give low latency, high memory capacity, and relatively high data transmission capacity at an additional cost limited to integrated circuit blocks. We first use information theory to estimate the unexplored potential of existing multi-drop bus structures. Hereby showing that reduction of the number of endpoints for multi-drop buses, is by no means based on the fundamental limit of the data transmission capacity of the bus structure. Two test-chips have been designed and fabricated to experimentally demonstrate the feasibility of several Gb/s data-rates over multidrop buses, with limited cost overhead and no latency penalty. The test-chips implement decision feedback equalization, adopted for high speed multi-drop use. The equalizers feature digital filter implementations which, in combination with high speed DACs, enable the use of long digital filters for high speed decision feedback equalization. Blind adaptation has also been implemented to demonstrate extraction of channel characteristics during data transmission. The use of single sided equalization has been proposed in order to limit the need for equalization implementation to the host side of a DRAM memory bus. Furthermore, we propose to utilize the reciprocal properties of the communication channel to ensure that single sided equalization can be performed without any channel characterization hardware on the memory chips. Finally, issues related to evaluation of high-speed channels are addressed and the on-chip structures used for channel evaluation in this project are presented.

Pupils, and most of all girls, drop out of organized sports in the ages 13-18. The purpose of this survey was to study which motives girls had to proceed in sports together with differences between certain groups. This study was based on a survey which included 86 responses from girls active in sports in 10 different compounds. The results showed that the most frequent motives to do sports were to have fun and to feel well. Differences showed were that the ones who trained more often and the ones who practiced more than one sport found that to work hard was an important motive, compared to the other groups. The ones that trained more often also found that to have fun was an important motive in difference to the group which trained in less extent. The organizational factors that could influence on the girls’ exercise were the coaches’ motivational techniques and the athletes’ experiences of competition in a negative way.

This thesis presents an axisymmetric numerical model to simulate interfacial flows near a sharp corner, where contact line pinning occurs. The method has been used to analyze drop imbibition into a capillary. To evaluate the performance of the numerical method, for a liquid drop initially placed partially within a capillary, a thermodynamic model has also been developed, to predict equilibrium states. The first part of this thesis presents an axisymmetric VoF algorithm to simulate interfacial flows near a sharp corner. (1) A new method to exactly calculate the normals and curvatures of any circle with a radius as small as the grid size is presented. This method is a hybrid least squares height function technique which fits a discretized osculating circle to a curve, from which interface normals and curvature can be evaluated. (2) A novel technique for applying the contact angle boundary condition has been devised, based on the definition of an osculating circle near a solid phase. (3) A new flux volume construction technique is presented, which can be applied to any split advection scheme. Unlike the traditional approach where the flux volumes are assumed rectangular, the new flux volumes can be either trapezoidal or triangular. The new technique improves the accuracy and consistency of the advection scheme. (4) Explicit PLIC reconstruction expressions for axisymmetric coordinates have been derived. (5) Finally, a numerical treatment of VoF for contact line motion near a sharp corner is presented, base on the idea of contact line pinning and an edge contact angle. The second part of the thesis is on the imbibition of a drop into an open capillary. A thermodynamic analysis based on minimization of an interfacial surface energy function is presented to predict equilibrium configurations of drops. Based on the drop size compared to the hole size, the equilibrium contact angle, and the geometry of the capillary, the drop can be totally imbibed by the capillary, or may not wet the capillary at all. The thesis concludes with application of the numerical scheme to the same problem, to examine the dynamics of wetting or dewetting of a capillary. All of the simulations yield results that correspond to the equilibrium states predicted by the thermodynamic analysis, but offer additional insight on contact line motion and interface deformation near the capillary edge.

This study examined the associations between social adversity, barriers-to-care (logistical obstacles, wait-time) and participation in children’s mental health treatment. The theoretical role of child symptoms (impact on the child, family burden) was addressed. Records were obtained for 1,963 parents who had accessed community-based care for their child (3-17 years). Data were collected as part of a provincial (Ontario, Canada) screening and outcome measurement initiative. The data were analyzed using multivariate logistic regression. Children with behavioural problems were at increased risk for attrition from treatment (OR=1.47, p < 0.001). The effect held upon controlling for age, gender, and co-morbid emotional symptoms; however, it was explained by child functional impairment. Similar effects were not found for the impact of symptoms on the family. Dropout was greater for adolescents (OR=1.43, p < 0.01) than younger children. Disadvantaged youth were more likely to drop out than more advantaged clients (OR=1.86, p < 0.001). Perceptions of difficulties in attending treatment were associated with a decreased risk (OR=0.89, p < 0.001). The adversity and service relationships were not mediated by child behavioural symptoms, functioning, or family burden. Waiting for care did not influence parent decisions to participate. Moderation analyses showed effects for adversity, service obstacles, emotional symptoms, functional impairment, and family burden for clients with behavioural problems. These children were more likely to drop out if they were socially disadvantaged, or had functional impairment at intake to services. However, completion was more likely for co-morbid children, and parental reports of burden. Families were also willing to overcome access difficulties in order to continue with treatment. There were few findings for children without behavioural problems. The results suggest a focus on other constructs, such as parent cognitions, that may link adversity and barriers with participation. The effects for symptoms as a moderator, suggests different levels of service provision based on sub-types of children. Efforts to engage “high-risk” clients are necessary. On the other hand, resources for intensive services would be appropriate for clients with more severe problems.