Effect of music on submaximal cycling

Objective. Athletes frequently report training to music, yet there have been relatively few studies that have addressed the benefit of exercising with music. Design. Volunteer men and women (N=30), aged between 18 and 40 years, performed an initial familiarisation session. Part of this session involved the measurement of maximal oxygen consumption. With at least a 48-hour intervening period, this was then followed by a first 20-minute submaximal cycling session, at 80% of maximal oxygen consumption. At least 48 hours later a second submaximal cycling session was performed. Subjects were randomly divided into two groups. Group A cycled without music and group B cycled with music for the first submaximal cycling session. Subjects underwent the same testing procedure for the second submaximal cycling session, but this time group A cycled to music and group B cycled without music. Subjects served as their own controls. Setting. The study was performed in the physiology exercise laboratory, at the University of the Witwatersrand. Main outcome measures. During the submaximal sessions heart rate, perceived exertion (Borg scale) and plasma lactate concentration were assessed. Subjects completed a post-test questionnaire once both submaximal cycling sessions were completed. Results. There were no significant differences in physiological variables (change in plasma lactate and heart rate), nor were there any significant differences in Borg scale ratings when the subjects cycled with and without music. However, according to the post-test questionnaire 67% of subjects identified the cycling session with music to be easier than the session without music. Conclusion. Listening to music while performing submaximal cycling resulted in no physiological benefit. Yet, the cycling session done in conjunction with music was deemed, by the majority of the subjects, to be easier than the cycling session without music. South African Journal of Sports Medicine Vol. 20 (1) 2008: pp. 28-3

Moduli-Induced Vacuum Destabilisation

We look for ways to destabilise the vacuum. We describe how dense matter environments source a contribution to moduli potentials and analyse the conditions required to initiate either decompactification or a local shift in moduli vevs. We consider astrophysical objects such as neutron stars as well as cosmological and black hole singularities. Regrettably neutron stars cannot destabilise realistic Planck coupled moduli, which would require objects many orders of magnitude denser. However gravitational collapse, either in matter-dominated universes or in black hole formation, inevitably leads to a destabilisation of the compact volume causing a super-inflationary expansion of the extra dimensions.Comment: 21 pages, 12 figure

Evaluation of two interaction techniques for visualization of dynamic graphs

Several techniques for visualization of dynamic graphs are based on different spatial arrangements of a temporal sequence of node-link diagrams. Many studies in the literature have investigated the importance of maintaining the user's mental map across this temporal sequence, but usually each layout is considered as a static graph drawing and the effect of user interaction is disregarded. We conducted a task-based controlled experiment to assess the effectiveness of two basic interaction techniques: the adjustment of the layout stability and the highlighting of adjacent nodes and edges. We found that generally both interaction techniques increase accuracy, sometimes at the cost of longer completion times, and that the highlighting outclasses the stability adjustment for many tasks except the most complex ones.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016

Prediction of peptide and protein propensity for amyloid formation

Understanding which peptides and proteins have the potential to undergo amyloid formation and what driving forces are responsible for amyloid-like fiber formation and stabilization remains limited. This is mainly because proteins that can undergo structural changes, which lead to amyloid formation, are quite diverse and share no obvious sequence or structural homology, despite the structural similarity found in the fibrils. To address these issues, a novel approach based on recursive feature selection and feed-forward neural networks was undertaken to identify key features highly correlated with the self-assembly problem. This approach allowed the identification of seven physicochemical and biochemical properties of the amino acids highly associated with the self-assembly of peptides and proteins into amyloid-like fibrils (normalized frequency of β-sheet, normalized frequency of β-sheet from LG, weights for β-sheet at the window position of 1, isoelectric point, atom-based hydrophobic moment, helix termination parameter at position j+1 and ΔGº values for peptides extrapolated in 0 M urea). Moreover, these features enabled the development of a new predictor (available at http://cran.r-project.org/web/packages/appnn/index.html) capable of accurately and reliably predicting the amyloidogenic propensity from the polypeptide sequence alone with a prediction accuracy of 84.9 % against an external validation dataset of sequences with experimental in vitro, evidence of amyloid formation

Gorenstein homological algebra and universal coefficient theorems

We study criteria for a ring—or more generally, for a small category—to be Gorenstein and for a module over it to be of finite projective dimension. The goal is to unify the universal coefficient theorems found in the literature and to develop machinery for proving new ones. Among the universal coefficient theorems covered by our methods we find, besides all the classic examples, several exotic examples arising from the KK-theory of C*-algebras and also Neeman’s Brown–Adams representability theorem for compactly generated categories

X-ray emission from isolated neutron stars

X-ray emission is a common feature of all varieties of isolated neutron stars (INS) and, thanks to the advent of sensitive instruments with good spectroscopic, timing, and imaging capabilities, X-ray observations have become an essential tool in the study of these objects. Non-thermal X-rays from young, energetic radio pulsars have been detected since the beginning of X-ray astronomy, and the long-sought thermal emission from cooling neutron star's surfaces can now be studied in detail in many pulsars spanning different ages, magnetic fields, and, possibly, surface compositions. In addition, other different manifestations of INS have been discovered with X-ray observations. These new classes of high-energy sources, comprising the nearby X-ray Dim Isolated Neutron Stars, the Central Compact Objects in supernova remnants, the Anomalous X-ray Pulsars, and the Soft Gamma-ray Repeaters, now add up to several tens of confirmed members, plus many candidates, and allow us to study a variety of phenomena unobservable in "standard'' radio pulsars.Comment: Chapter to be published in the book of proceedings of the 1st Sant Cugat Forum on Astrophysics, "ICREA Workshop on the high-energy emission from pulsars and their systems", held in April, 201

The development of study-specific self-efficacy during grammar school.(Zur Entwicklung der studienspezifischen Selbstwirksamkeit in der Oberstufe)

Article is in German. Even if more and more German adolescents acquire a university entrance qualification, not all of them finally enrol at a university. In particular, the transition from school to university strongly depends on parent’s education. Even with the same marks in school, adolescents from non-academic households are less likely to enrol in universities than adolescents from academic housholds. One important reason is their lower belief to master a university study. This study analyses a specific intervention in grammar school to improve study-specific self- efficacy, the belief in one’s capabilities to master a university study, using a longitudinal design. We apply a difference-in-difference framework and show that programme participation significantly improves the study-specific self-efficacy for puplis from non- academic families but not for those from academic families. Hence, such a programme could reduce social disparities between both groups

Cisplatin and Oxaliplatin Toxicity: Importance of Cochlear Kinetics as a Determinant for Ototoxicity

Background Cisplatin is a commonly used platinum anti-cancer drug. Regrettably cisplatin has dose-limiting ototoxic side effects, e.g. the drug can induce an irreversible hearing loss. The ototoxic mechanisms of cisplatin have not been elucidated in the human ear and no clinically useful oto-protectors are yet available. Cisplatin is a necessary part of many treatment regimes. Its beneficial therapeutic effects might be reduced if cisplatin was excluded from the treatment in order to protect the hearing function. In this work the ototoxic effects of cisplatin are studied with the aim to better understand the mechanisms behind the irreversible hearing loss induced by this drug. Oxaliplatin is a second generation platinum-derivative anti-cancer drug, free from ototoxic side effects in clinical practice. The effects of oxaliplatin on the inner ear have been studied in this work and the results are compared with cisplatin treatment. The two drugs differ regarding both anti-cancer effects and side effects, which could be attributed to differences in pharmacokinetic factors, cellular uptake and apoptotic mechanisms. The thioredoxin redox system with the enzyme thioredoxin reductase (TrxR) was studied in cochleae due to a suggested DNA-independent apoptotic mechanism of the hair cells. The cochlear pharmacokinetics of cisplatin was assessed and the transport protein organic cation transporter 2 (OCT2) was studied in relation to the ototoxic effect of cisplatin. Material and methods Cultured human colon carcinoma cells and cell cultures of rat organ of Corti were used for apoptosis studies in vitro following exposure to cisplatin and oxaliplatin. Cisplatin and oxaliplatin were administered i.v. to guinea pigs, followed by in vivo sampling of blood, cerebrospinal fluid (CSF) and scala tympani (ST) perilymph. Liquid chromatography with post-column derivatization was used to determine the concentration of parent drug in the samples. Electrophysiological hearing thresholds and the loss of hair cells were assessed to evaluate their ototoxic effects. Phenformin, a potential blocker of OCT2 was administered and the ototoxic side effect of cisplatin was evaluated. For immunohistochemical studies, cochlea from rat, guinea pig and pig were used, where TrxR and OCT2 were evaluated in the cochlea. TrxR-assays were used to measure the TrxR activity in cochlear tissue, both in vivo and in vitro. Results The results from the in vitro studies showed that addition of either cisplatin or oxaliplatin to the culture medium in organ of Corti cell cultures caused a similar amount of outer hair cell loss and inhibition of TrxR activity. Cisplatin exposure to cultured human colon carcinoma cells also reduced the activity of TrxR. The results from the in vivo studies showed that a considerable concentration of cisplatin was present in ST perilymph as compared with weak concentrations of oxaliplatin after high dose oxaliplatin i.v. Ten minutes after cisplatin administration, its concentration in ST perilymph was 4-fold higher in the basal turn of the cochlea as compared to the apex. Cisplatin could be analysed in ST perilymph for up to 120 min. Phenformin i.v. did not reduce the ototoxic side-effect of cisplatin. Positive immunoreactivity to TrxR was evident in both hair cells and spiral ganglion cells. Futhermore, OCT2 was expressed in the supporting cells of organ of Corti and in the spiral ganglion cells. Conclusion The transport of cisplatin to the vulnerable cells of hearing seems to be of major importance for the ototoxic effects. An early high concentration of cisplatin in the base of the cochlea and delayed elimination of cisplatin from ST perilymph may be related to the cisplatin-induced loss of outer hair cells in the basal turn of the cochlea. Cisplatin and oxaliplatin both cause similar ototoxic effects when the organ of Corti is directly exposed in vitro. The thioredoxin redox system with the TrxR enzyme may well play a critical role in cisplatininduced ototoxicity. The presence of OCT2 in the supporting cells indicates that this transport protein is primarily not involved in the uptake of cisplatin from the systemic circulation but rather from the deeper compartments of the cochlea. The knowledge elicited in this work will hopefully suggest objectives for further studies in order to develop oto-protective treatments to preserve the hearing of cisplatin treated patients