Comment on "Are financial crashes predictable?"

Comment on "Are financial crashes predictable?", L. Laloux, M. Potters, R. Cont, J.P Aguilar and J.-P. Bouchaud, Europhys. Lett. 45, 1-5 (1999)Comment: 2 pages including 2 figures. Subm. to Eur. Phys Lett. Previous error in fig. 1 correcte

Articulated multiple couch assembly Patent

Shock absorbing articulated multiple couch assembl

The log-periodic-AR(1)-GARCH(1,1) model for financial crashes

This paper intends to meet recent claims for the attainment of more rigorous statistical methodology within the econophysics literature. To this end, we consider an econometric approach to investigate the outcomes of the log-periodic model of price movements, which has been largely used to forecast financial crashes. In order to accomplish reliable statistical inference for unknown parameters, we incorporate an autoregressive dynamic and a conditional heteroskedasticity structure in the error term of the original model, yielding the log-periodic-AR(1)-GARCH(1,1) model. Both the original and the extended models are fitted to financial indices of U. S. market, namely S&P500 and NASDAQ. Our analysis reveal two main points: (i) the log-periodic-AR(1)-GARCH(1,1) model has residuals with better statistical properties and (ii) the estimation of the parameter concerning the time of the financial crash has been improved.Comment: 17 pages, 4 figures, 12 tables, to appear in Europen Physical Journal

The Marginal Cost of Frailty Among Medicare Patients on Hemodialysis.

Introduction:Dialysis patients incur disproportionately high costs compared with other Medicare beneficiaries. Care for frail individuals may be even more costly. We examined the extent to which frailty contributes to higher costs among dialysis patients. Methods:We used ACTIVE/ADIPOSE (A Cohort to Investigate the Value of Exercise/Analyses Designed to Investigate the Paradox of Obesity and Survival in ESRD) enrollees (adult hemodialysis patients evaluated from June 2009 to August 2011) in a retrospective cohort analysis. Individuals using Medicare as the primary payer were included. Fried's frailty phenotype was evaluated at baseline, 12, and 24 months. Costs were derived from linkage with the US Renal Data System (USRDS) and Medicare claims data. We used generalized estimating equations (GEEs) incorporating time-updated frailty and costs to evaluate adjusted point estimates and the marginal cost associated with being frail. We also investigated if frail patients who died during the study incurred higher costs than those who survived. Results:Among 771 enrollees in ACTIVE/ADIPOSE, 425 met inclusion criteria. Mean age was 56 ± 13 years, body mass index (BMI) 29.2 ± 7.1 kg/m2, 42.4% were women, and 29.0% were frail at baseline. Over a mean follow-up of 2.3 years, frail individuals incurred 22% (95% confidence interval [CI] 9.6%-35.8%) higher costs compared with nonfrail individuals ($87,600 per patient per year [pppy], 95$71,800 pppy, 95% CI 64,800-79,600), the difference was driven primarily by higher inpatient expenditures. The difference between frail and nonfrail patients' inpatient expenditures was even more pronounced among those who died during the study compared with those who survived. Conclusions:Frail dialysis patients incur a significantly higher cost relative to their nonfrail counterparts, primarily driven by higher inpatient costs. Frail patients near end of life incur even higher costs

Energetic Extremes in Aquatic Locomotion by Coral Reef Fishes

Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a range of swimming vertebrates, however, has suggested that flapping paired appendages around a rigid body may be an extremely efficient means of aquatic locomotion. Using intermittent flow-through respirometry, we found exceptional energetic performance in the Bluelined wrasse Stethojulis bandanensis, which maintains tuna-like optimum cruising speeds (up to 1 metre s(-1)) while using 40% less energy than expected for their body size. Displaying an exceptional aerobic scope (22-fold above resting), streamlined rigid-body posture, and wing-like fins that generate lift-based thrust, S. bandanensis literally flies underwater to efficiently maintain high optimum swimming speeds. Extreme energetic performance may be key to the colonization of highly variable environments, such as the wave-swept habitats where S. bandanensis and other wing-finned species tend to occur. Challenging preconceived notions of how best to power aquatic locomotion, biomimicry of such lift-based fin movements could yield dramatic reductions in the power needed to propel underwater vehicles at high speed.Funding was provided by the Australian Research Council (to CJF) and the Danish Agency for Science, Technology and Innovation (to JFS). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Effect of a pedometer-based walking intervention on body composition in patients with ESRD: a randomized controlled trial.

BackgroundA randomized trial of a pedometer-based intervention with weekly activity goals led to a modest increase in step count among dialysis patients. In a secondary analysis, we investigated the effect of this intervention on body composition.MethodsSixty dialysis patients were randomized to standard care or a 6-month program consisting of 3 months of pedometers and weekly step count targets and 3 months of post-intervention follow-up. We obtained bioelectrical impedance spectroscopy (BIS) data on 54 of these patients (28 control, 26 intervention) and used linear mixed-modeling (adjusted for sex and dialysis modality) to estimate differences in change in total-body muscle mass (TBMM) adjusted for height2, fat mass (kg), and body mass index (BMI) (kg/m2) between control and intervention groups.ResultsThe median age of participants was 57.5 years (53-66), and 76% were men. At baseline, there was no significant difference between groups in age, BMI, race, or body composition, but there were more men in the intervention group. After 3 months, patients in the intervention group increased their average daily steps by 2414 (95% CI 1047, 3782) more than controls (p < 0.001), but there were no significant differences in body composition. However, at 6 months, participants in the intervention had a significantly greater increase from baseline in TBMM of 0.7 kg/m2 (95% CI 0.3, 1.13), decrease in fat mass (- 4.3 kg [95% CI -7.1, - 1.5]) and decrease in BMI (- 1.0 kg/m2 [95% CI -1.8, - 0.2]) relative to controls. In post-hoc analysis, each increase of 1000 steps from 0 to 3 months was associated with a 0.3 kg decrease in fat mass (95% CI 0.05, 0.5) from 0 to 6 months, but there was no dose-response relationship with TBMM/ht2 or BMI.ConclusionA pedometer-based intervention resulted in greater decreases in fat mass with relative preservation of muscle mass, leading to a greater decrease in BMI over time compared with patients not in the intervention. These differences were driven as much by worsening in the control group as by improvement in the intervention group. Step counts had a dose-response relationship with decrease in fat mass.Trial registrationClinicalTrials.gov (NCT02623348). 02 December 2015

Stochastics theory of log-periodic patterns

We introduce an analytical model based on birth-death clustering processes to help understanding the empirical log-periodic corrections to power-law scaling and the finite-time singularity as reported in several domains including rupture, earthquakes, world population and financial systems. In our stochastics theory log-periodicities are a consequence of transient clusters induced by an entropy-like term that may reflect the amount of cooperative information carried by the state of a large system of different species. The clustering completion rates for the system are assumed to be given by a simple linear death process. The singularity at t_{o} is derived in terms of birth-death clustering coefficients.Comment: LaTeX, 1 ps figure - To appear J. Phys. A: Math & Ge