EFFECT OF STRETCH REFLEX BLOCKAGE ON THE KINETICS AND KINEMATICS OF THREE JUMPERS PERFORMANCES

It has been postulated that the stretch reflex enhances force production in walking (Capady & Stein, 1986), running (Deitz, 1981), hopping (Melvill-Jones & Watt, 1971) and jumping (Bosco, et a1., 1982). In addition, it is widely accepted that the elastic component of muscles plays an important role in dynamic activities such as jumping. For example, during eccentric contraction ofthe jump, energy may be stored in the series elastic components which can be re-used during the subsequent concentric contraction. In fact, evidence from isolated muscle, as well as from intact muscle in humans, has been presented to show that the elastic energy storage contributed to enhanced work, force, velocity, and power of the positive phase of muscle contraction (e.g., Cavagna, 1965, 1971 a,b). All of the enhanced performances during the positive phase was attributed to fast stretching of a muscle prior to the shortening. It is well known that in stretching a muscle the muscle spindle will be stretched during which a volley of discharge is carried by an afferent path to evoke the stretch reflex. It was concluded that EMG activity in the extensor muscle is much higher in a countermovement jump (CMJ) than in a squat jump. Thus, the enhanced performance produced by a CMJ is related to a combination of elastic energy storage and the stretch reflex (Bosco, et a1., 1982)

E-Learning Readiness of Jordanian Universities

E-learning became very important to the universities success and it considered as one of the key success factors, in which it’s enhanced the competitive advantage and help in competing strongly in the market. Using Information technologies and sharing tools will add value to the educational process and by using these tools; the universities will have the power of innovation and creativity. E-learning helps in developing, managing and maintaining the students knowledge, on the other hand, it enhances the performance and learning capacity to remain innovation and competitive. This paper is measuring the readiness of the Jordanian universities for e-learning. It presents the main findings of a survey conducted to evaluate the e-learning readiness. The survey helped in analyzing three levels used for the measurement: ICT infrastructure, universities lecturers and students’ readiness, and the maturity of the external environment. Keywords: E-learning, IT infrastructure, Demand, External Environment, and HR readiness

The role of explicit contrast in adjective acquisition: a cross-linguistic longitudinal study of adjective production in spontaneous child speech and parental input

Experimental studies demonstrate that contrast helps toddlers to extend the meanings of novel adjectives. This study explores whether antonym co-occurrence in spontaneous speech also has an effect on adjective use by the child. The authors studied adjective production in longitudinal speech samples from 16 children (16–36 months) acquiring eight different languages. Adjectives in child speech and child-directed speech were coded as either unrelated or related to a contrastive term in the preceding context. Results show large differences between children in the growth of adjective production. These differences are strongly related to contrast use. High contrast users not only increase adjective use earlier, but also reach a stable level of adjective production in the investigated period. Average or low contrast users increase their adjective production more slowly and do not reach a plateau in the period covered by this study. Initially there is a strong relation between contrast use in child speech and child-directed speech, but this relation diminishes with age. </jats:p

The Mu3e Data Acquisition

The Mu3e experiment aims to find or exclude the lepton flavor violating decay μ+→e+e−e+ with a sensitivity of one in 10 16 muon decays. The first phase of the experiment is currently under construction at the Paul Scherrer Institute (PSI, Switzerland), where beams with up to 10 8 muons per second are available. The detector will consist of an ultra-thin pixel tracker made from High-Voltage Monolithic Active Pixel Sensors (HV-MAPS) , complemented by scintillating tiles and fibers for precise timing measurements. The experiment produces about 100Gbit/s of zero-suppressed data, which are transported to a filter farm using a network of field programmable gate arrays (FPGAs) and fast optical links. On the filter farm, tracks and three-particle vertices are reconstructed using highly parallel algorithms running on graphics processing units, leading to a reduction of the data to 100 Mbyte/s for mass storage and offline analysis. This article introduces the system design and hardware implementation of the Mu3e data acquisition and filter farm

Awareness of cognitive decline trajectories in asymptomatic individuals at risk for AD

Background: Lack of awareness of cognitive decline (ACD) is common in late-stage Alzheimer’s disease (AD). Recent studies showed that ACD can also be reduced in the early stages. Methods: We described different trends of evolution of ACD over 3 years in a cohort of memory-complainers and their association to amyloid burden and brain metabolism. We studied the impact of ACD at baseline on cognitive scores’ evolution and the association between longitudinal changes in ACD and in cognitive score. Results: 76.8% of subjects constantly had an accurate ACD (reference class). 18.95% showed a steadily heightened ACD and were comparable to those with accurate ACD in terms of demographic characteristics and AD biomarkers. 4.25% constantly showed low ACD, had significantly higher amyloid burden than the reference class, and were mostly men. We found no overall effect of baseline ACD on cognitive scores’ evolution and no association between longitudinal changes in ACD and in cognitive scores. Conclusions: ACD begins to decrease during the preclinical phase in a group of individuals, who are of great interest and need to be further characterized. Trial registration: The present study was conducted as part of the INSIGHT-PreAD study. The identification number of INSIGHT-PreAD study (ID-RCB) is 2012-A01731-42

Technical design of the phase I Mu3e experiment

The Mu3e experiment aims to find or exclude the lepton flavour violating decay $\mu \rightarrow eee$ at branching fractions above $10^{-16}$. A first phase of the experiment using an existing beamline at the Paul Scherrer Institute (PSI) is designed to reach a single event sensitivity of $2\cdot 10^{-15}$. We present an overview of all aspects of the technical design and expected performance of the phase~I Mu3e detector. The high rate of up to $10^{8}$ muon decays per second and the low momenta of the decay electrons and positrons pose a unique set of challenges, which we tackle using an ultra thin tracking detector based on high-voltage monolithic active pixel sensors combined with scintillating fibres and tiles for precise timing measurements.Comment: 114 pages, 185 figures. Submitted to Nuclear Instruments and Methods A. Edited by Frank Meier Aeschbacher This version has many enhancements for better readability and more detail

Low Cognitive Awareness, but Not Complaint, is a Good Marker of Preclinical Alzheimer's Disease

Subjective cognitive decline (SCD) may result from many conditions, including Alzheimer's disease (AD)