The Relationship between Competitive State Anxiety and Imagery Ability in High School Track and Field Athletics

The purpose of this study was to investigate the relationship between imagery ability, subcomponents of competitive state anxiety, and performance outcomes in high school track and field athletes during the competitive season. Following IRB approval and parental consent, sixteen participants were recruited to participate in a four-week study using two thoroughly validated assessment tools: The Sport\u27s Imagery Questionnaire (SIQ) and The Competitive State Anxiety Inventory #2 (CSAI-2). This study explored imagery ability by qualifying several aspects of imagery ability. Instead of focusing exclusively on frequency, (a commonly cited limitation to the applicability of the SIQ) the SIQ was modified to include three more variables: vividness of the image, ease of the practice, and control of the image or actions being performed. Athletes took the CSAI-2 while recalling their personal best and before two competitions to measure state anxiety. The SIQ was only taken once as a trait measure. Statistical analysis for competition one revealed statistically significant negative correlations between cognitive anxiety and performance, somatic anxiety and performance, imagery and cognitive anxiety, and imagery and somatic anxiety. Results also discovered a strong, positive correlation between self-confidence and performance. Imagery did not significantly predict performance outcomes according to ANOVA analysis. Imagery may have been operating as a mediating or moderating variable, and this should be pursued in the future. Competition two failed to produce any significant relationships, and there was no significant different between the use of frequency or all four imagery ability variables

The immune system as a target for antibiotics

Studies on antibiotics, oxytetracycline (OxyTC) in particular, are presented in this thesis with respect to the influence of these drugs on the immune system of carp and chickens. Special attention was paid to the pharmacokinetic behaviour of OxyTC.ImmunologyCarp ( Cyprinuscarpio ) leukocytes from spleen, pronephros and mesonephros showed a clear invitro mitogenic response. The DNA synthesis of PHA-stimulated pronephric cells was reduced to about 50% of the mitogen-activated controls at therapeutic concentrations of 4 - 6 μg OxyTC/ml. Doxycycline (DC) was even more suppressive: 50% inhibition at 1 - 2.5 μg/ml. The difference between the two tetracycline analogues may relate to the better lipid-solubility of DC. In addition. OxyTC (10 μg/ml) and DC (5 μg/ml) markedly reduced the incorporation of 3H-thymidine into alloantigen-stimulated pronephric leukocytes by 61% and 98%. respectively. Furthermore. it was demonstrated that OxyTC changed the kinetics of the mitogenic response at relative low concentrations (5 - 15 μg/ml). A dose-dependent delay of 1 - 2 days was observed. In fact. the antibiotic suppression was transient. Obviously. the impairment of cellular functions like DNA synthesis is not due to cell killing.The immuno-modulating effects of OxyTC was also demonstrated for chicken peripheral blood (PBL) and spleen leukocytes. However, the kinetics of the 3H-thymidine incorporation by lectin-activated PBL showed that the DNA synthesis was severely suppressed in stead of delayed. The production of the amplifying/regulatory factor interleukin 2 (IL-2) was not affected in the presence of the antimicrobial agent. Whereas, the uptake of 3H-thymidine by IL-2-dependent T cell blasts was strongly reduced. It was concluded that the T cell blast is one of the targets for OxyTC.Investigations in carp on the kinetics of the primary anti-SRBC antibody response, during a short-term OxyTC treatment invivo , revealed that the kinetics of the plaque forming cell response was not significantly affected by OxyTC. In contrast, the number of plaque forming cells was significantly decreased. Furthermore. the anti-SRBC antibody production was delayed by 2 - 4 days. However. within 12 - 14 days post immunization the same antibody levels were detected as in the control group. indicating the temporary effect of OxyTC on the immune response.PharmacokineticsThe objective of the pharmacokinetic studies was to investigate plasma disposition, distribution, bioavailability and elimination of OxyTC in carp, rainbow trout ( Salmogairdneri ) and African catfish ( Clariasgariepinus ).Analysis of the plasma drug concentration time curves following intravenous (i.v.) OxyTC administration (60 mg/kg) revealed distinct phases. The two- and three-compartment open model adequately described the plasma drug levels in catfish and trout, respectively. A three-compartment model was also used for carp to derive pharmacokinetic parameters. Compared with mammals, an extended average final elimination half-live was observed in all three fish species following i.v. OxyTC administration: carp: 139.8 h; trout: 89.5 h; catfish: 80.3 h. Between the three species, marked differences were observed with respect to the rate diffusion constants, distribution volume of the central compartment. apparent distribution volume and body clearance.A bioavailability was observed of 80 - 86% following intramuscular (i.m.) injection of OxyTC (60 mg/kg). Whereas, a bioavailability of only 0.6% was achieved in carp with the oral route of administration.Immunology and PharmacokineticsOxytetracycline interfered with the immune response in carp. However. data were needed concerning the pharmacokinetic behaviour of this drug in carp. Tissue distribution studies following a single i.m. OxyTC injection (60 mg/kg) revealed that the drug was accumulating in pronephros, bone tissue and scales. After 21 days the average OxyTC concentrations were 2.9. 5.2 and 4.7 μg/ml, respectively. The pronephros is an important lymphoid and haemopoietic organ in fish. Furthermore, the pharmacokinetic data showed that high plasma levels (>50 μg/ml) were detected over a relatively long time period. These data provide more insight into the action of OxyTC upon immuno-modulation.Immuno-pharmacokinetic researchWhen defence mechanisms fail to prevent the establishment of infective micro-organisms in the host. the consequence will be disease. Under these conditions antibiotics are valuable tools for the therapy of bacterial infections. Interference of an antibiotic with the immunological responses will decrease the defensive potential. Therefore, it is important to exclude any immuno- suppression by antimicrobial drugs in animals and man. This is obvious. because the defence mechanisms have to ensure the final elimination of pathogens.In this context pharmacokinetic studies. including tissue distribution, are of great importance. These studies provide data concerning the behaviour of drugs within the body. Extreme differences can be expected with respect to animal species, age and disease status.The combined action of immune system and antimicrobial drugs will increase the defensive capacity. Therefore, it is emphasized that an immuno-pharmacological approach is a prerequisite to prevent immuno- toxicological events and to optimize the use of antibiotics. Consequently, the fundamental aspects of this type of research will support an effective human and veterinary medical management

Analysis and Optimization of a Piezoelectric Harvester on a Car Damper

AbstractLow power levels obtained from piezoelectric conversion of ambient vibrations appear to be a promising solution to supply wireless sensors embedded inside automotive suspension. However such a solution requires overall an optimum power extraction from the piezoelectric power harvester. This leads to the use of a sufficiently accurate and flexible modelling method to find the optimal characterics and configuration of the harvester. To this end, an innovative bond graph model of the piezoelectric harvester embedded in the quarter vehicle system is proposed for providing the harvested power when a car travels a road with a speed bump at 30km/h. Results show that around of 0.5 milliwatt electrical power is harvested when varying key parameters like the location and characteristics of the piezoelectric device

Dynamic simulation and optimization of artificial insect-sized flapping wings for a bioinspired kinematics using a two resonant vibration modes combination

This paper addresses the design of the elastic structure of artificial wings to optimize their dynamical behaviour to reproduce insect wings kinematics. Our bioinspired kinematics is based on the original concept of using the resonant properties of the wing structure in order to combine the motion of two vibration modes, a flapping and a twisting mode, in a quadrature phase shift. Oneway of achieving this particular combination is to optimize the geometry and elastic characteristics of the flexible structure such that the two modes are successive in the eigenspectrum and close in frequency. This paper first proposes a semi-analytical model, based on assembled Euler-Bernoulli beams, to understand, compute and optimize the artificial wing dynamic vibrations. Then, using this model, it is shown that it is possible to obtain several artificial wing structures with a flapping and a twisting mode close in frequency. Finally, experimental validations are performed on micromachined insect-sized prototypes to validate the model and the concept

Two modes resonant combined motion for insect wings kinematics reproduction and lift generation

This paper presents an original concept using a two resonant vibration modes combined motion to reproduce insect wings kinematics and generate lift. The key issue is to design the geometry and the elastic characteristics of artificial wings such that a combination of flapping and twisting motions in a quadrature phase shift could be obtained. This qualitatively implies to bring the frequencies of the two resonant modes closer. For this purpose, a polymeric prototype was micromachined with a wingspan of 3 cm, flexible wings and a single actuator. An optimal wings configuration was determined with a modeling and validated through experimental modal analyses to verify the proximity of the two modes frequencies. A dedicated lift force measurement bench was developed and used to demonstrate a lift force equivalent to the prototype weight. Finally, at the maximum lift frequency, high-speed camera measurements confirmed a kinematics of the flexible wings with flapping and twisting motions in phase quadrature as expected.ANR-ASTRID CLEARFlight (ANR-13-ASTR-0012), RENATECH program, Direction Generale de l’Armement et Haut-de-France Regio

Linear electromagnetic energy harvester system embedded on a vehicle suspension: From modeling to performance analysis

Although linear electromagnetic energy harvester (LEH) is a promising technique for converting energy in a vehicle suspension, due to the large displacements, one of the main drawbacks of the solutions inside the vehicle is still their size and complexity. To address this issue, this paper focuses on the design and fabrication of a fully embedded LEH without any modification of the suspension initial structure. After a determination of the electrical, mechanical and electromechanical parameters using a Finite Element analysis, the dynamic efficiency is highlighted with a global Bond Graph model. This formalism is well adapted to simulate energy transfers inside multiphysic systems and to reduce the computational time, whereas the finite element model is not exploitable for a complete suspension simulation. In order to validate the Bond Graph simulation results, an embedded prototype has been built and tested in a laboratory environment. The embedded LEH system delivers around 10 W for a solicitation of linear velocity of 1 m/s which is sufficient to power a classical electronic circuit which is in good correlation with the measured ones and significant power has been obtained

Investigation of Cross-Coupling in Piezoelectric Transducer Arrays and Correction

Cross-coupling in piezoelectric transducer arrays is an undesirable phenomenon which decreases the performance of these devices. Indeed, when one element of a transducer is driven, it generates parasitic displacement fields at the radiating surfaces of the neighboring elements, which changes the directivity of the array. The objective of this paper is to investigate the cross-coupling effects on the piezoelectric transducer arrays performance and to propose solutions to reduce this parasitic phenomenon. In this context, it is demonstrated that a filling material having high mechanical losses contributes to the reduction of cross-coupling. In addition to this, a procedure of active cancellation of cross-coupling is successfully tested in the case of two transducer arrays vibrating in the transverse mode for the first prototype and thickness mode for the second one. Finally, the ability of the method is demonstrated even when the displacement at the radiating surface of the transducer array is not uniform

Développement d’un insecte artificiel. Nanodrone dédié à la surveillance intra-bâtiment

Dans l’optique de réaliser de la surveillance intra-bâtiment avec un système autonome, mobile, très discret, des recherches sont en cours pour développer des nanodrones. Elles se concentrent sur la compréhension et l’imitation du vol battu des insectes et sur les aspects de la miniaturisation. Cet article décrit la conception et la réalisation d’un insecte artificiel à ailes résonantes à l’aide des technologies de microfabrication de la microélectronique. Un actionneur électromagnétique induit un mouvement de flexion/torsion des ailes correspondant à une cinématique similaire à celle des insectes. L’estimation des phénomènes aéroélastiques en grands déplacements est réalisée à l’aide d’un modèle basé sur les éléments finis et une formulation analytique de l’aérodynamique. Une validation expérimentale est ensuite proposée