System level comparison of FDMA vs. CDMA (under conference guideline constraint)

The margin that is required to mitigate the near-far problem in a Code Division Multiple Access (CDMA) mobile satellite system is determined by the radio-propagation model selected, the distribution of the users in clear and shadowed environments, and implementation techniques. The use of revenue potential as a means of evaluating the relative merits of CDMA and Frequency Division Multiple Access (FDMA) systems is a convenient way to rationalize the performance of systems using high-gain and low-gain antennas. The revenue potential of CDMA is much greater than the revenue potential for FDMA for a particular satellite design considered

The effect of medical grade compression garments on the repeated-bout effect in non-resistance trained men

Abstract Whilst compression garments (CG) may enhance recovery from exercise‐induced muscle damage (EIMD), many recovery strategies can attenuate adaptative responses. Therefore, the effects of CG on recovery from EIMD, and the rapid protective adaptations known as the repeated bout effect (RBE) were investigated. Thirty‐four non‐resistance‐trained males (18–45 years) randomly received class II medical‐grade CG or placebo for 72 h following eccentrically‐focused lower‐body exercise, in a double‐blind, randomised controlled trial. Indices of EIMD were assessed at baseline, 0, 24, 48 and 72 h post‐exercise, before exercise and testing were repeated after 14 days. Results were analysed using a three‐way (time × condition × bout) linear mixed‐effects model. Exercise impaired isometric and isokinetic strength, with soreness and thigh circumference elevated for 72 h (P  0.05), despite small to moderate effect sizes (ES, reported alongside 90% confidence intervals) for isokinetic strength (ES from 0.2 [−0.41, 0.82] to 0.65 [0.03, 1.28]). All variables recovered faster after the repeated bout (P < 0.005). However, RBE for peak isokinetic force was impaired in CG at 60° s−1 (group × bout interaction: χ2 = 4.24, P = 0.0395; ES = −0.56 [−1.18, 0.07]) and completely absent at 120° s−1 (χ2 = 16.2, P < 0.001, ES = −0.96 [−1.61, −0.32]) and 180° s−1 (χ2 = 10.4, P = 0.001, ES = −0.72 [−1.35, −0.09]). Compression blunted RBE at higher isokinetic velocities without improving recovery in non‐resistance‐trained males, potentially contraindicating their use following unaccustomed exercise in this population

Childhood loneliness as a predictor of adolescent depressive symptoms: an 8-year longitudinal study

Childhood loneliness is characterised by children’s perceived dissatisfaction with aspects of their social relationships. This 8-year prospective study investigates whether loneliness in childhood predicts depressive symptoms in adolescence, controlling for early childhood indicators of emotional problems and a sociometric measure of peer social preference. 296 children were tested in the infant years of primary school (T1 5 years of age), in the upper primary school (T2 9 years of age) and in secondary school (T3 13 years of age). At T1, children completed the loneliness assessment and sociometric interview. Their teachers completed externalisation and internalisation rating scales for each child. At T2, children completed a loneliness assessment, a measure of depressive symptoms, and the sociometric interview. At T3, children completed the depressive symptom assessment. An SEM analysis showed that depressive symptoms in early adolescence (age 13) were predicted by reports of depressive symptoms at age 8, which were themselves predicted by internalisation in the infant school (5 years). The interactive effect of loneliness at 5 and 9, indicative of prolonged loneliness in childhood, also predicted depressive symptoms at age 13. Parent and peer-related loneliness at age 5 and 9, peer acceptance variables, and duration of parent loneliness did not predict depression. Our results suggest that enduring peer-related loneliness during childhood constitutes an interpersonal stressor that predisposes children to adolescent depressive symptoms. Possible mediators are discussed

The effect of medical grade compression garments on the repeated-bout effect in non-resistance trained men

Whilst compression garments (CG) may enhance recovery from exercise-induced muscle damage (EIMD), many recovery strategies can attenuate adaptative responses. Therefore, the effects of CG on recovery from EIMD, and the rapid protective adaptations known as the repeated bout effect (RBE) were investigated. Thirty-four non-resistance trained males (18–45 y) randomly received class II medical-grade CG or placebo for 72 h following eccentrically-focused lower-body exercise, in a double-blind, randomised controlled trial. Indices of EIMD were assessed at baseline, 0, 24, 48 and 72 h post-exercise, before exercise and testing were repeated after 14 d. Results were analysed using a three-way (time x condition x bout) linear mixed-effects model. Exercise impaired isometric and isokinetic strength, with soreness and thigh circumference elevated for 72 h (p 0.05), despite small to moderate effect sizes (ES, reported alongside 90% confidence intervals) for isokinetic strength (ES from 0.2 [-0.41, 0.82] to 0.65 [0.03, 1.28]). All variables recovered faster after the repeated bout (p < 0.005). However, RBE for peak isokinetic force was impaired in CG at 60 ⁰.s-1 (group x bout interaction: χ2 = 4.24, p = 0.0395; ES = -0.56 [-1.18, 0.07]) and completely absent at 120 ⁰.s-1 (χ2 =16.2, p < 0.001, ES = -0.96 [-1.61, -0.32]) and 180 ⁰.s-1 (χ2 =10.4, p = 0.001, ES = -0.72 [-1.35, -0.09]). Compression blunted RBE at higher isokinetic velocities without improving recovery in non-resistance trained males, potentially contraindicating their use following unaccustomed exercise in this population

Gleevec, an Abl family inhibitor, produces a profound change in cell shape and migration (in press)

The issue of how contractility and adhesion are related to cell shape and migration pattern remains largely unresolved. In this paper we report that Gleevec (Imatinib), an Abl family kinase inhibitor, produces a profound change in the shape and migration of rat bladder tumor cells (NBTII) plated on collagen-coated substrates. Cells treated with Gleevec adopt a highly spread D-shape and migrate more rapidly with greater persistence. Accompanying this more spread state is an increase in integrin-mediated adhesion coupled with increases in the size and number of discrete adhesions. In addition, both total internal reflection fluorescence microscopy (TIRFM) and interference reflection microscopy (IRM) revealed a band of small punctate adhesions with rapid turnover near the cell leading margin. These changes led to an increase in global cell-substrate adhesion strength, as assessed by laminar flow experiments. Gleevec-treated cells have greater RhoA activity which, via myosin activation, led to an increase in the magnitude of total traction force applied to the substrate. These chemical and physical alterations upon Gleevec treatment produce the dramatic change in morphology and migration that is observed