2,003 research outputs found
The influence of voluntary upper body exercise on the performance of stimulated paralysed human quadriceps
In this study the influence of voluntary upper body exercise on the performance of stimulated paralysed human quadriceps was investigated in five subjects with spinal cord lesions in the thoracic spine. The experimental setup consisted of computer-controlled stimulation of the quadriceps using electrodes on the surface of the skin, a dynamometer for isometric or isokinetic loading of the lower leg, and a rowing ergometer for upper body exercise. In all subjects, quadriceps fatigue tests were conducted to study the influence of upper body exercise on knee torque during sustained continuous or intermittent stimulation of quadriceps. The relative asymptotic torque appeared to be significantly higher with the presence of upper body exercise than without. This was consistently found both between trials (starting with or without upper body exercise) as well as within trials, when upper body exercise was started or stopped during the trial. No significant influence of upper body exercise on the time constant of initial torque decline was found
Competitive interactions are mediated in a sex-specific manner by arbuscular mycorrhiza in Antennaria dioica
Plants usually interact with other plants, and the outcome of such interaction ranges from facilitation to competition depending on the identity of the plants, including their sexual expression. Arbuscular mycorrhizal (AM) fungi have been shown to modify competitive interactions in plants. However, few studies have evaluated how AM fungi influence plant intraspecific and interspecific interactions in dioecious species.
The competitive abilities of female and male plants of Antennaria dioica were examined in a greenhouse experiment. Females and males were grown in the following competitive settings: (i) without competition, (ii) with intrasexual competition, (iii) with intersexual competition, and (iv) with interspecific competition by Hieracium pilosella – a plant with similar characteristics to A. dioica. Half of the pots were grown with Claroideoglomus claroideum, an AM fungus isolated from the same habitat as the plant material. We evaluated plant survival, growth, flowering phenology, and production of AM fungal structures.
Plant survival was unaffected by competition or AM fungi. Competition and the presence of AM fungi reduced plant biomass. However, the sexes responded differently to the interaction between fungal and competition treatments. Both intra- and interspecific competition results were sex-specific, and in general, female performance was reduced by AM colonization. Plant competition or sex did not affect the intraradical structures, extraradical hyphae, or spore production of the AM fungus.
These findings suggest that plant sexual differences affect fundamental processes such as competitive ability and symbiotic relationships with AM fungi
De grafemische buffer : aspecten van een spellingstoornis
A spelling disorder that received much attention recently is the so-called graphemic buffer impairment. Caramazza et al. (1987) presented the first systematic case study of a patient with this disorder. Miceli & Capasso (2006) provide an extensive overview of the relevant literature. This article adds to the literature by describing a Dutch case, i.e. patient BM. We demonstrate how specific features of Dutch and Dutch orthography interact with the graphemic buffer impairment. In addition, we paid special attention to the influence of grapheme position on the patient’s spelling accuracy. For this we used, in contrast with most of the previous literature, the proportional accountability method described in Machtynger & Shallice (2009). We show that by using this method the underlying error distribution can be more optimally captured than with classical methods. The result of this analysis replicates two distributions that have been previously reported in the literature. Finally, attention will be paid to the role of phonology in the described disorder
De grafemische buffer : aspecten van een spellingstoornis
Ce riche volume de 373 pages rassemble les contributions pour un colloque qui fut organisé les 30 novembre et 1 décembre 2012 par le “Centro Studi Sigismondo Castromediano e Gino Rizzo” à Cavallino di Lecce. Le personnage historique de premier plan qui fait l’objet du volume est Sigismondo Castromediano (Cavallino 1811-1895), surnommé le « Bianco Duca », noble de la région des Pouilles, arrêté en 1848 pour activité patriotique au sein de la Giovine Italia, condamné à trente ans de bagne, puis..
Gradient-free quantum optimization on NISQ devices
Variational Quantum Eigensolvers (VQEs) have recently attracted considerable
attention. Yet, in practice, they still suffer from the efforts for estimating
cost function gradients for large parameter sets or resource-demanding
reinforcement strategies. Here, we therefore consider recent advances in
weight-agnostic learning and propose a strategy that addresses the trade-off
between finding appropriate circuit architectures and parameter tuning. We
investigate the use of NEAT-inspired algorithms which evaluate circuits via
genetic competition and thus circumvent issues due to exceeding numbers of
parameters. Our methods are tested both via simulation and on real quantum
hardware and are used to solve the transverse Ising Hamiltonian and the
Sherrington-Kirkpatrick spin model.Comment: 13 pages, 6 figures, comments welcome
Sex differences in distress from infidelity in early adulthood and in later life:A replication and meta-analysis of Shackelford et al. (2004)
Shackelford and colleagues (2004) found that men, compared to women, are more distressed by sexual than emotional infidelity, and this sex difference continued into older age. We conducted four high-powered replications (total N = 1,952) of this effect and found different results. A meta-analysis of original and replication studies finds the sex difference in younger samples (though with a smaller effect size), and no effect among older samples. Furthermore, we found attitude toward uncommitted sex to be a mediator (although not consistently in the same direction) between participant sex and relative distress between sexual and emotional infidelity. We hypothesize that the discrepancies between the original and replication studies may be due to changing cultural attitudes about sex across time. Confirming this speculative interpretation requires further investigation. Keywords: evolutionary psychology, human nature, sex differences, cultural differences, replicatio
Identification of T-cell antigens specific for latent mycobacterium tuberculosis infection.
BACKGROUND: T-cell responses against dormancy-, resuscitation-, and reactivation-associated antigens of Mycobacterium tuberculosis are candidate biomarkers of latent infection in humans. METHODOLOGY/PRINCIPAL FINDINGS: We established an assay based on two rounds of in vitro restimulation and intracellular cytokine analysis that detects T-cell responses to antigens expressed during latent M. tuberculosis infection. Comparison between active pulmonary tuberculosis (TB) patients and healthy latently M. tuberculosis-infected donors (LTBI) revealed significantly higher T-cell responses against 7 of 35 tested M. tuberculosis latency-associated antigens in LTBI. Notably, T cells specific for Rv3407 were exclusively detected in LTBI but not in TB patients. The T-cell IFNgamma response against Rv3407 in individual donors was the most influential factor in discrimination analysis that classified TB patients and LTBI with 83% accuracy using cross-validation. Rv3407 peptide pool stimulations revealed distinct candidate epitopes in four LTBI. CONCLUSIONS: Our findings further support the hypothesis that the latency-associated antigens can be exploited as biomarkers for LTBI
Comparison of RBE values of high- LET α-particles for the induction of DNA-DSBs, chromosome aberrations and cell reproductive death
<p>Abstract</p> <p>Background</p> <p>Various types of radiation effects in mammalian cells have been studied with the aim to predict the radiosensitivity of tumours and normal tissues, e.g. DNA double strand breaks (DSB), chromosome aberrations and cell reproductive inactivation. However, variation in correlations with clinical results has reduced general application. An additional type of information is required for the increasing application of high-LET radiation in cancer therapy: the Relative Biological Effectiveness (RBE) for effects in tumours and normal tissues. Relevant information on RBE values might be derived from studies on cells in culture.</p> <p>Methods</p> <p>To evaluate relationships between DNA-DSB, chromosome aberrations and the clinically most relevant effect of cell reproductive death, for ionizing radiations of different LET, dose-effect relationships were determined for the induction of these effects in cultured SW-1573 cells irradiated with gamma-rays from a Cs-137 source or with α-particles from an Am-241 source. RBE values were derived for these effects. Ionizing radiation induced foci (IRIF) of DNA repair related proteins, indicative of DSB, were assessed by counting gamma-H2AX foci. Chromosome aberration frequencies were determined by scoring fragments and translocations using premature chromosome condensation. Cell survival was measured by colony formation assay. Analysis of dose-effect relations was based on the linear-quadratic model.</p> <p>Results</p> <p>Our results show that, although both investigated radiation types induce similar numbers of IRIF per absorbed dose, only a small fraction of the DSB induced by the low-LET gamma-rays result in chromosome rearrangements and cell reproductive death, while this fraction is considerably enhanced for the high-LET alpha-radiation. Calculated RBE values derived for the linear components of dose-effect relations for gamma-H2AX foci, cell reproductive death, chromosome fragments and colour junctions are 1.0 ± 0.3, 14.7 ± 5.1, 15.3 ± 5.9 and 13.3 ± 6.0 respectively.</p> <p>Conclusions</p> <p>These results indicate that RBE values for IRIF (DNA-DSB) induction provide little valid information on other biologically-relevant end points in cells exposed to high-LET radiations. Furthermore, the RBE values for the induction of the two types of chromosome aberrations are similar to those established for cell reproductive death. This suggests that assays of these aberrations might yield relevant information on the biological effectiveness in high-LET radiotherapy.</p
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