No differences between beetroot juice and placebo on competitive 5-km running performance: A double-blind, placebo-controlled trial

We examined the effect of beetroot juice on endurance running performance in “real-world” competitive settings. One-hundred recreational runners (54% male; mean ± standard deviation, age = 33.3 ± 12.3 years, training history = 11.9 ± 8.1 years, hours per week training = 5.9 ± 3.5) completed a quasi-randomised, double-blind, placebo-controlled study of 5-km competitive time-trials. Participants performed four trials separated by one week in the order of pre-baseline, two experimental, and one post-baseline. Experimental trials consisted of the administration of 70-mL nitrate rich beetroot juice (containing ~4.1 mmol of nitrate, Beet It Sport®) or nitrate depleted placebo (containing ~0.04 mmol of nitrate, Beet It Sport®) 2.5 hours prior to time-trials. Time to complete 5-km was recorded for each trial. No differences were shown between pre- and post-baseline (P = 0.128, CV = 2.66%). The average of these two trials is therefore used as baseline. Compared to baseline, participants ran faster with beetroot juice (mean differences = 22.2 ± 5.0 s, P < 0.001, d = 0.08) and placebo (22.9 ± 4.5 s, P < 0.001, d = 0.09). No differences in times were shown between beetroot juice or placebo (0.8 ± 5.7 s, P < 0.875, d = 0.00). These results indicate that an acute dose of beetroot juice does not improve competitive 5-km time-trial performance in recreational runners compared to placebo

Who responds to a placebo? Factors associated with response to placebo during a double-blind randomised controlled trial

INTRODUCTION: The placebo effect, a desirable outcome resulting from a person’s expected and/or learned response to a treatment or situation, may significantly influence the interpretation of double-blind, randomised controlled trials (RCT). High placebo responder rates may under-estimate the true efficacy of a treatment. It is therefore important for researchers conducting RCTs to be cognisant of factors influencing the placebo response. In this study, we performed a retrospective analysis of a RCT of participants’ response to placebo beetroot juice on 5-km running performance. METHODS: Participants were 70 recreational runners (male 51.2%; mean ± SD = age = 32.0 ± 10.4 years, hours per week training = 6.16 ± 3.98, 5-km personal best = 24:28 minutes:seconds). After completing measures of sport supplement use and their beliefs about sport supplements, participants completed 5-km time-trials at baseline and with the ingestion of nitrate depleted placebo (containing ~0.04 mmol of nitrate, Beet It Sport®). The smallest worthwhile change was calculated to identify placebo responders and backward linear regression identified variables associated with the placebo response. RESULTS: Nearly two-thirds of participants were identified as placebo responders (63%). Compared to baseline, time to run 5-km among placebo responders was 2.76 ± 0.36%, whereas for non-responders it was -1.45 ± 0.46%. Sport supplement use (β = -2.162, p = 0.042), sport supplement beliefs (β = -0.712, p = 0.034) and being male (β = -2.030, p = 0.022) predicted the response to placebo. Stronger beliefs about sport supplements also influenced the magnitude of improvement in 5-km times in the placebo condition compared to baseline (β = 0.820, p = 0.028). CONCLUSION: Results demonstrate that participants recruited to a RCT of beetroot juice on 5-km running performance were more likely to respond to a placebo if they used sport supplements, reported strong beliefs in their effectiveness and were male. Given that interpretation of RCTs can be influenced by the placebo effect, researchers using these research designs should consider measuring and controlling for these variables in their analyses. Further data on what may influence the response to a placebo is needed to help inform interpretation of RCTs

Discrete Formulation for the dynamics of rods deforming in space

We describe the main ingredients needed to create, from the smooth lagrangian density, a variational principle for discrete motions of a discrete rod, with corresponding conserved Noether currents. We describe all geometrical objects in terms of elements on the linear Atiyah bundle, using a reduced forward difference operator. We show how this introduces a discrete lagrangian density that models the discrete dynamics of a discrete rod. The presented tools are general enough to represent a discretization of any variational theory in principal bundles, and its simplicity allows to perform an iterative integration algorithm to compute the discrete rod evolution in time, starting from any predefined configurations of all discrete rod elements at initial times

Making postgraduate students and supervisors aware of the role of emotions in the PhD process

Emotions are an integral part of the PhD process. A range of emotions are common and to be expected. How do emotions affect the PhD process for both postgraduate students and their supervisors? How can we make our emotions work positively for us in the PhD process? To explore answers to these questions, three lecturers currently supervising postgraduates and three postgraduates at various stages in their doctoral studies collectively pooled their experiences. We developed an interactive workshop that was recently conducted for postgraduate students at Murdoch University and at the Australian Association for Social Research annual conference 2002. This presentation will explore the role that emotions play in the PhD process and how supervisors and postgraduates alike can benefit from reflecting on this issue. A number of practical (and humorous) tips will be provided as well as examples from others' PhD experiences. The role of emotions at the beginning, middle and end of a PhD program will be explored. The data collection and analysis phases are a time when emotions may run riot. Trepidation is especially common when fieldwork or data collection is involved, as is anger when postgraduate's views about how the world works are challenged and then sadness (and relief!) when the data collection phase is finished. We will discuss how supervisors can assist their postgraduates to make these feelings work for them. The presentation will also explore the emotions that arise from the supervisor-postgraduate partnership

Structure of the PII signal transduction protein of Neisseria meningitidis at 1.85 Ȃ resolution

Copyright @ 2006 International Union of CrystallographyThe PII signal transduction proteins GlnB and GlnK are implicated in the regulation of nitrogen assimilation in Escherichia coli and other enteric bacteria. PII-like proteins are widely distributed in bacteria, archaea and plants. In contrast to other bacteria, Neisseria are limited to a single PII protein (NMB 1995), which shows a high level of sequence identity to GlnB and GlnK from Escherichia coli (73 and 62%, respectively). The structure of the PII protein from N. meningitidis (serotype B) has been solved by molecular replacement to a resolution of 1.85 Ȃ. Comparison of the structure with those of other PII proteins shows that the overall fold is tightly conserved across the whole population of related proteins, in particular the positions of the residues implicated in ATP binding. It is proposed that the Neisseria PII protein shares functions with GlnB/GlnK of enteric bacteria.This study is funded by the Medical Research Council UK and Europe (SPINE) consortium (European Commission Grant No. QLG2-CT-2002-00988)

A systematic review of the role of bisphosphonates in metastatic disease

Objectives: To identify evidence for the role of bisphosphonates in malignancy for the treatment of hypercalcaemia, prevention of skeletal morbidity and use in the adjuvant setting. To perform an economic review of current literature and model the cost effectiveness of bisphosphonates in the treatment of hypercalcaemia and prevention of skeletal morbidity Data sources: Electronic databases (1966-June 2001). Cochrane register. Pharmaceutical companies. Experts in the field. Handsearching of abstracts and leading oncology journals (1999-2001). Review methods: Two independent reviewers assessed studies for inclusion, according to predetermined criteria, and extracted relevant data. Overall event rates were pooled in a meta-analysis, odds ratios ( OR) were given with 95% confidence intervals (CI). Where data could not be combined, studies were reported individually and proportions compared using chi- squared analysis. Cost and cost-effectiveness were assessed by a decision analytic model comparing different bisphosphonate regimens for the treatment of hypercalcaemia; Markov models were employed to evaluate the use of bisphosphonates to prevent skeletal-related events (SRE) in patients with breast cancer and multiple myeloma. Results: For acute hypercalcaemia of malignancy, bisphosphonates normalised serum calcium in >70% of patients within 2-6 days. Pamidronate was more effective than control, etidronate, mithramycin and low-dose clodronate, but equal to high dose clodronate, in achieving normocalcaemia. Pamidronate prolongs ( doubles) the median time to relapse compared with clodronate or etidronate. For prevention of skeletal morbidity, bisphosphonates compared with placebo, significantly reduced the OR for fractures (OR [95% CI], vertebral, 0.69 [0.57-0.84], non-vertebral, 0.65 [0.54-0.79], combined, 0.65 [0.55-0.78]) radiotherapy 0.67 [0.57-0.79] and hypercalcaemia 0.54 [0.36-0.81] but not orthopaedic surgery 0.70 [0.46-1.05] or spinal cord compression 0.71 [0.47-1.08]. However, reduction in orthopaedic surgery was significant in studies that lasted over a year 0.59 [0.39-0.88]. Bisphosphonates significantly increased the time to first SRE but did not affect survival. Subanalyses were performed for disease groups, drugs and route of administration. Most evidence supports the use of intravenous aminobisphosphonates. For adjuvant use of bisphosphonates, Clodronate, given to patients with primary operable breast cancer and no metastatic disease, significantly reduced the number of patients developing bone metastases. This benefit was not maintained once regular administration had been discontinued. Two trials reported significant survival advantages in the treated groups. Bisphosphonates reduce the number of bone metastases in patients with both early and advanced breast cancer. Bisphosphonates are well tolerated with a low incidence of side-effects. Economic modelling showed that for acute hypercalcaemia, drugs with the longest cumulative duration of normocalcaemia were most cost-effective. Zoledronate 4 mg was the most costly, but most cost-effective treatment. For skeletal morbidity, Markov models estimated that the overall cost of bisphosphonate therapy to prevent an SRE was pound250 and pound1500 per event for patients with breast cancer and multiple myeloma, respectively. Bisphosphonate treatment is sometimes cost-saving in breast cancer patients where fractures are prevented. Conclusions: High dose aminobisphosphonates are most effective for the treatment of acute hypercalcaemia and delay time to relapse. Bisphosphonates significantly reduce SREs and delay the time to first SRE in patients with bony metastatic disease but do not affect survival. Benefit is demonstrated after administration for at least 6-12 months. The greatest body of evidence supports the use of intravenous aminobisphosphonates. Further evidence is required to support use in the adjuvant setting

STIS ultraviolet/optical spectroscopy of `warm' ultraluminous infrared galaxies

(Abridged) We present high spatial resolution ultraviolet and optical spectroscopy, obtained using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope, of nuclear structures within four `warm' Ultraluminous Infrared Galaxies (ULIRGs). We find an AGN in at least three, and probably all four of our sample, hosted in a compact, optically luminous `knot'. In three cases these knots were previously identified as a putative AGN nucleus from multiband optical imaging. Three of the sample also harbor a starburst in one or more knots, suggesting that the optically luminous knots seen in local ULIRGs are the most likely sites of the dust-shrouded starburst and AGN activity that power the infrared emission. The four AGN have a diverse range of properties; two are classical narrow line AGN, one shows both broad and narrow lines and evidence for lines of sight from the narrow through to the broad line regions, and one is plausibly a FeLoBAL AGN. The probable presence in one object of an FeLoBAL AGN, which are extremely rare in the QSO population, supports the idea that LoBAL AGN may be youthful systems shrouded in gas and dust rather than AGN viewed along a certain line of sight. The three starbursts for which detailed constraints are possible show a smaller range in properties; all three bursts are young with two having ages of ~4Myr and the third having an age of 20Myr, suggesting that ULIRGs undergo several bursts of star formation during their lifetimes. None of the starbursts show evidence for Initial Mass Function slopes steeper than about 3.3. The metallicities of the knots for which metallicities can be derived are all at least 1.5 times the Solar value. The properties of one further starburst knot are consistent with it being the forming core of an elliptical galaxy.Comment: ApJ, accepte

Southern Sky Redshift Survey: Clustering of Local Galaxies

We use the two-point correlation function to calculate the clustering properties of the recently completed SSRS2 survey. The redshift space correlation function for the magnitude-limited SSRS2 is given by xi(s)=(s/5.85 h-1 Mpc)^{-1.60} for separations between 2 < s < 11 h-1 Mpc, while our best estimate for the real space correlation function is xi(r) = (r/5.36 h-1 Mpc)^{-1.86}. Both are comparable to previous measurements using surveys of optical galaxies over much larger and independent volumes. By comparing the correlation function calculated in redshift and real space we find that the redshift distortion on intermediate scales is small. This result implies that the observed redshift-space distribution of galaxies is close to that in real space, and that beta = Omega^{0.6}/b < 1, where Omega is the cosmological density parameter and b is the linear biasing factor for optical galaxies. We also use the SSRS2 to study the dependence of xi on the internal properties of galaxies. We confirm earlier results that luminous galaxies (L>L*) are more clustered than sub-L* galaxies and that the luminosity segregation is scale-independent. We find that early types are more clustered than late types, but that in the absence of rich clusters, the relative bias between early and late types in real space, is not as strong as previously estimated. Furthermore, both morphologies present a luminosity-dependent bias, with the early types showing a slightly stronger dependence on luminosity. We also find that red galaxies are significantly more clustered than blue ones, with a mean relative bias stronger than that seen for morphology. Finally, we find that the relative bias between optical and iras galaxies in real space is b_o/b_I $\sim$ 1.4.Comment: 43 pages, uses AASTeX 4.0 macros. Includes 8 tables and 16 Postscript figures, updated reference

Bayes-X: a Bayesian inference tool for the analysis of X-ray observations of galaxy clusters

We present the first public release of our Bayesian inference tool, Bayes-X, for the analysis of X-ray observations of galaxy clusters. We illustrate the use of Bayes-X by analysing a set of four simulated clusters at z=0.2-0.9 as they would be observed by a Chandra-like X-ray observatory. In both the simulations and the analysis pipeline we assume that the dark matter density follows a spherically-symmetric Navarro, Frenk and White (NFW) profile and that the gas pressure is described by a generalised NFW (GNFW) profile. We then perform four sets of analyses. By numerically exploring the joint probability distribution of the cluster parameters given simulated Chandra-like data, we show that the model and analysis technique can robustly return the simulated cluster input quantities, constrain the cluster physical parameters and reveal the degeneracies among the model parameters and cluster physical parameters. We then analyse Chandra data on the nearby cluster, A262, and derive the cluster physical profiles. To illustrate the performance of the Bayesian model selection, we also carried out analyses assuming an Einasto profile for the matter density and calculated the Bayes factor. The results of the model selection analyses for the simulated data favour the NFW model as expected. However, we find that the Einasto profile is preferred in the analysis of A262. The Bayes-X software, which is implemented in Fortran 90, is available at http://www.mrao.cam.ac.uk/facilities/software/bayesx/.Comment: 22 pages, 11 figure