DYNAMIC ANALYSIS OF THE STARTING ACTION AND STARTING ACCELERATION

The objective of the analysis has been to establish some most important parameters of the starting action and their correlation with the starting acceleration. The sample of tested subjects comprised 8 male sprinters and 6 female sprinters of the national team of Slovenia. The criterion test was a 30-m sprint from the crouch start. The parameters of the starting action were measured by special electronic starting blocks, and the parameters of the starting acceleration by a system of photocells, placed at spacings of 5-10-15-20-25-30 metres. In the analysis, 16 variables of the starting action and 6 variables of the starting acceleration have been considered. In order to establish the association between the starting action and starting acceleration, the method of correlation analysis at an error probability level of 5% was adopted. The largest differences between male and female sprinters have been established in the magnitude of the horizontal force and the force impulse exerted on the starting blocks, while the smallest differences can be seen in the reaction times. The results of correlation analysis show that the starting acceleration in male sprinters is primarily correlated with the starting reaction time (R= 0.83), the maximal pressure exerted on the front starting block (R= 0.78), and the force gradient on the front starting block (R=0.60). However, in female sprinters, the efficiency of the starting acceleration depends on the latent reaction time (R=0.63), the starting reaction time (R=0.92), the maximal pressure exerted on the rear starting block (R=0.66), and the impulse of the push-off force exerted on the rear starting block (R=0.74). The diagrams of the starting acceleration show that male sprinters perform the push-off from the starting blocks in an eccentric-concentric manner, while female sprinters carry it out in a concentric manner. The results obtained are important for the optimisation of the starting technique and starting speed. At the same time they also enable us better control and planning of the process of technical training of Sprinters

Modeling Approaches for Gain, Noise and Time Response of Avalanche Photodiodes for X-Rays Detection

We report on a suite of modeling approaches for the optimization of Avalanche Photodiodes for X-rays detection. Gain and excess noise are computed efficiently using a non-local/history dependent model that has been validated against full-band Monte Carlo simulations. The (stochastic) response of the detector to photon pulses is computed using an improved Random-Path-Length algorithm. As case studies, we consider diodes consisting of AlGaAs/GaAs multi-layers with separated absorption and multiplication regions. A superlattice creating a staircase conduction band structure is employed in the multiplication region to keep the multiplication noise low. Gain and excess noise have been measured in devices fabricated with such structure and successfully compared with the developed models

Specific Binding of the Pathogenic Prion Isoform: Development and Characterization of a Humanized Single-Chain Variable Antibody Fragment

Murine monoclonal antibody V5B2 which specifically recognizes the pathogenic form of the prion protein represents a potentially valuable tool in diagnostics or therapy of prion diseases. As murine antibodies elicit immune response in human, only modified forms can be used for therapeutic applications. We humanized a single-chain V5B2 antibody using variable domain resurfacing approach guided by computer modelling. Design based on sequence alignments and computer modelling resulted in a humanized version bearing 13 mutations compared to initial murine scFv. The humanized scFv was expressed in a dedicated bacterial system and purified by metal-affinity chromatography. Unaltered binding affinity to the original antigen was demonstrated by ELISA and maintained binding specificity was proved by Western blotting and immunohistochemistry. Since monoclonal antibodies against prion protein can antagonize prion propagation, humanized scFv specific for the pathogenic form of the prion protein might become a potential therapeutic reagent

Visible pump-mid infrared pump-broadband probe: Development and characterization of a three-pulse setup for single-shot ultrafast spectroscopy at 50 kHz

We report here an experimental setup to perform three-pulse pump-probe measurements over a wide wavelength and temperature range. By combining two pump pulses in the visible (650 nm-900 nm) and mid-IR (5 \u3bcm-20 \u3bcm) range, with a broadband supercontinuum white-light probe, our apparatus enables both the combined selective excitation of different material degrees of freedom and a full time-dependent reconstruction of the non-equilibrium dielectric function of the sample. We describe here the optical setup, the cryogenic sample environment, and the custom-made acquisition electronics capable of referenced single-pulse detection of broadband spectra at the maximum repetition rate of 50 kHz, achieving a sensitivity of the order of 10-4 over an integration time of 1 s. We demonstrate the performance of the setup by reporting data on a mid-IR pump, optical push, and broadband probe in a single crystal of Bi2Sr2Y0.08Ca0.92Cu2O8+\u3b4 across the superconducting and pseudogap phases

Nonlinear digital pre-distortion of transmitter components

We present a linear and nonlinear digital predistortion (DPD) tailored to the components of an optical transmitter. The DPD concept uses nonlinear models of the transmitter devices, which are obtained from direct component measurements. While the digital-to-analog converter and driver amplifier are modeled jointly by a Volterra series, the modulator is modeled independently as a Wiener system. This allows for block-wise compensation of the modulator by a Hammerstein system and a pre-distortion of the electrical components by a second Volterra series. In simulations and extensive experiments, the performance of our approach for nonlinear DPD is compared to an equivalent linear solution as well as to a configuration without any digital pre-distortion. The experiments were performed using M-ary quadrature-amplitude modulation (MQAM) formats ranging from 16-QAM to 128-QAM at a symbol rate of 32 GBd. It is shown that DPD improves the required optical signal-to-noise ratio at a bit error ratio of 2???10-2 by at least 1.2 dB. Nonlinear DPD outperforms linear DPD by an additional 0.9 dB and 2.7 dB for higher-order modulation formats such as 64-QAM and 128-QAM, respectively

Experimental comparison of 1.28 Tb/s Nyquist WDM vs. time-frequency packing

We experimentally compared terabit transmission employing 16QAM Nyquist WDM and QPSK Time-Frequency Packing. The two modulation schemes have been transmitted over the same link configuration. The latter showed slightly better performance in terms of spectral efficiency and reach, at the expense of a more expensive and complex hardware