Search results for " Stability"

Noise phenomena and soliton dynamics in long Josephson junctions

2013

In this work we computationally explore the transient dynamics of a noisy Josephson junction (JJ). Principal purpose is to investigate the behavior of the lifetime of the superconductive state as a function of the system and noise source parameters. The relations between the emerging phenomena and the evolution of the JJ order parameter φ, that is the phase difference between the macroscopic wave functions describing the superconducting condensate in the two electrodes, is deeply investigated. We focus our interest on the switching events from the superconducting metastable state, and in particular on the mean escape time (MET). In the used model, a long JJ can be represented by a string co…

Comorbid Fluency Difficulties in Reading and Math: Longitudinal Stability Across Early Grades

2018

We examined the prevalence of comorbidity of dysfluent reading and math skills longitudinally in a representative sample ( N = 1,928) and the stability of comorbid and single difficulties from first to fourth grades. The findings indicated that half the children who showed very low performance in one skill also evidenced low or very low performance in the other. Comorbid difficulties had somewhat higher prevalence in third and fourth graders than in first and second graders. The stability of comorbid difficulties was found to be established from Grade 2 onward, but the stability of single difficulties increased steadily across grades. Overall, the findings emphasize the relatively strong s…

pH stability of ophthalmic solutions.

2004

Background In this study, we evaluated the pH value of 17 ophthalmic solutions, and we investigated whether the pH of these solutions changed over time after the bottle was opened. Methods Fifteen bottles of each type of solution were chosen at random from different production lots. A 0.05-ml increment was taken from each bottle and was measured daily using a micropH 2002 Crison pH-meter over a period of 30 days. Results The results revealed differences between the pH values of the solutions; nine solutions presented pH values within ocular comfort range and eight solutions presented pH values between 3.5 and 6.4. Ten solutions presented non-statistically significant variations over time ( …

Tartrate-Resistant Acid Phosphatase 5b: A Novel Serum Marker of Bone Resorption

2000

Human serum contains two forms of tartrate-resistant acid phosphatase (TRAP), 5a and 5b. Of these, 5a contains sialic acid and 5b does not. We show here that antigenic properties and pH optimum of TRAP purified from human osteoclasts are identical to those of serum TRAP 5b and completely different from those of serum TRAP 5a, suggesting that 5b would be derived from osteoclasts and 5a from some other source. We developed a novel immunoassay specific for 5b using a monoclonal antibody O1A as capture antibody. O1A did not bind acid phosphatase derived from platelets and erythrocytes. Western analysis showed that O1A was specific for TRAP in both human bone and serum. We measured bound TRAP ac…

Graft Healing in ACL Reconstruction: Can We Enhance It in Clinical Practice?

2012

The ACL-Deficient Knee: A Problem Solving Approach, focuses on problem analysis and problem solving, as well as analyzing the possibility of prevention. In each chapter, the biomechanics, anatomy, etc. that are relevant to the topic are reviewed. There are chapters where highly specialized surgical techniques are presented (v. gr. double bundle reconstruction or meniscal transplant), as well as developing areas such as ACL tears in children, where we are finding a growing number of injuries due to the increase of sports at early ages Surgical reconstruction of the anterior cruciate ligament (ACL) using tendon grafts is the current standard to treat the functionally ACL-deficient knee. The s…

Evaluation of knee joint proprioception and balance of young female volleyball players: a pilot study

2015

[Purpose] The main purpose of our study was the evaluation of the effects of long-term volleyball practice on knee joint proprioception and balance of young female athletes. [Subjects and Methods] An observational case-control study was performed. The study enrolled 19 female volleyball players in the experimental group and 19 sedentary counterparts as controls. A Biodex balance system and dynamometer were used for the evaluations. The paired t-test was used to determine the significance of differences between the performance of athletes and controls. [Results] The knee proprioception analysis showed a significant difference at 60° joint position in active and passive tests. A similar trend…

Factores de rendimiento en el desplazamiento del tenista influenciados por el calzado. (Performance factors on tennis player displacements influenced…

2009

Los desplazamientos laterales son de gran importancia en el tenis. Sin embargo, no ha sido publicado ningun estudio sobre el efecto del calzado sobre el rendimiento en este tipo de movimientos. En el estudio participaron 5 jugadores habituales de tenis y se analizaron 10 calzados comerciales de tenis. El movimiento estudiado consistio en un desplazamiento lateral con parada y cambio de sentido, registrandose las fuerzas mediante una plataforma dinamometrica Dinascan-IBV y grabandose el movimiento con dos camaras de video S-VHS Panasonic WV-BL600. Los resultados de los ANOVAs realizados mostraron que algunas de las variables analizadas eran dependientes del calzado (p < 0.05). De estas, dest…

Postural Adjustments and Kinematic Index Finger Features in Frail Older Adults under Different Equilibrium Constraints

2021

Background: Anticipatory postural adjustments (APAs) are significantly affected by age and may represent restrictions on functional independence. Previous studies in young adults have already highlighted that changing postural stability (i.e., seated vs. upright posture) affects the motor planning and APAs. In frail older adults (FOAs), the effect of these different conditions of postural stability have not yet been established, and the present study aimed to disentangle this issue. Methods: Participants executed an arm-pointing task to reach a diode immediately after it turned on, under different conditions of stability (seated with and without foot support and in an upright posture). A ki…

2018

Beyond the classical paradigm that presents the Anticipatory Postural Adjustments (APAs) as a manner to create forces that counteract disturbances arising from the moving segment during a pointing task, there is a controversial discussion about the role APAs to facilitate the movement and perform a task accurately. In addition, arm kinematics features are classically used to infer the content of motor planning for the execution and the control of arm movements. The present study aimed to disentangle the conflicting role of APAs during an arm-pointing task in which the subjects reach a central diode that suddenly turns on, while their postural stability was manipulated. Three postures were a…

Ankle muscle strength discriminates fallers from non-fallers

2014

International audience; It is well known that center of pressure (CoP) displacement correlates negatively with the maximal isometric torque (MIT) of ankle muscles. This relationship has never been investigated in elderly fallers (EF). The purpose of this study was thus to analyze the relationship between the MIT of ankle muscles and CoP displacement in upright stance in a sample aged between 18 and 90 years old that included EF . The aim was to identify a threshold of torque below which balance is compromised. The MIT of Plantar flexors (PFs) and dorsal flexors (DFs) and CoP were measured in 90 volunteers: 21 healthy young adults (YA) (age: 24.1 +/- 5.0), 12 healthy middle-aged adults (MAA)…