Invariant higher-order variational problems II

Motivated by applications in computational anatomy, we consider a second-order problem in the calculus of variations on object manifolds that are acted upon by Lie groups of smooth invertible transformations. This problem leads to solution curves known as Riemannian cubics on object manifolds that are endowed with normal metrics. The prime examples of such object manifolds are the symmetric spaces. We characterize the class of cubics on object manifolds that can be lifted horizontally to cubics on the group of transformations. Conversely, we show that certain types of non-horizontal geodesics on the group of transformations project to cubics. Finally, we apply second-order Lagrange--Poincar\'e reduction to the problem of Riemannian cubics on the group of transformations. This leads to a reduced form of the equations that reveals the obstruction for the projection of a cubic on a transformation group to again be a cubic on its object manifold.Comment: 40 pages, 1 figure. First version -- comments welcome

Predictors of the successful outcome of one-year survivors of coronary artery bypass surgery

This study was conducted on a South African cohort to establish the actors that may predict the successful outcome of coronary artery bypass surgery when assessed in terms of improved quality of life one year after the surgery. Information was sought on the socio-economic status of patients, their risk-factor profiles and clinical history. From the patient files, information was recorded on left ventricular ejection fraction, number of vessels bypassed, bypass time, and aortic cross-clamp time. The characteristics that were predictive of a successful outcome one year after surgery were identified. Patients in this study represented a high-risk population with multiple risk factors (obese, heavy smokers, hypertensive, hypercholesterolaemic, inactive, family history of heart disease, diabetes, and regular intake of alcohol). Measured medical parameters could not distinguish between the group with an improved quality of life and the group who did not have improved quality of life. One year after CABG all patients with an improved quality of life were men. The additional identified predictor variables for a successful outcome were: being married, patients' height, the knowledge that smoking affects the cardiovascular system, number of years that sporting activities were stopped prior to CABG surgery, a better quality sex life after the operation, acceptance of self-responsibility for rehabilitation, and the spouse knowing the diet the patient should follow. The predictors of a successful outcome at the time of the operation were: being married (OR = 22.6; p = 0.02); taller than 170 cm (OR = 15.5; p = 0.01); stopped all sporting activities for a period less than 20 years prior to their surgery (OR 11.4; p = 0.01). We concluded that the outcome of coronary artery bypass surgery could not be predicted on the basis of a medical model that considers exclusively the extent of the patient's disease and associated co-morbidities. Patients should be carefully selected and an intensive post-operative educational intervention should be provided to patients and their spouses/caregivers

Preload maintenance protects against a depression in left ventricular systolic, but not diastolic, function immediately after ultraendurance exercise

This article has been made available through the Brunel Open Access Publishing Fund and is available from the specified link - Copyright © 2006 BMJ Publishing Group.Objective: To investigate indices of left ventricular (LV) function before and after a 224 km Ironman triathlon, specifically in the presence of unaltered haemodynamic loading. Method: LV loading and function were assessed before and after the race using M mode and Doppler echocardiography in 39 (mean (SD) age 33 (8) years, body mass 77.6 (8.6) kg; 36 male) triathletes in the Trendelenburg position. Specifically left ventricular end diastolic volume (LVEDV) was assessed to estimate preload, and systolic blood pressure to estimate afterload as well as heart rate (HR). Systolic functional indices included ejection fraction (EF) and the end systolic pressure/volume ratio (ESPV), and diastolic functional indices included peak mitral flow velocity in early (E) and atrial (A) filling as well as the ratio E/A. Data obtained before and after the race were compared by t tests, and delta LV functional indices were correlated with delta heart rate. Results: Preload (LVEDV: 143 (34) ml before v 147 (34) ml after) and afterload (systolic blood pressure 121 (13) v 115 (20) mm Hg) were not significantly altered after the race (p>0.05), nor were EF (61 (8)% v 58 (10)%) and ESPV (2.4 (0.9) v 2.1 (0.8) mm Hg/cm3). The diastolic filling ratio E/A was significantly reduced after the race (1.73 (0.25) v 1.54 (0.23); p0.05). Conclusion: When preload and afterload are unaltered after the race, because of the adoption of a unique assessment posture, LV systolic function is not depressed. A depression in LV diastolic function persists which is not explained by an increase in heart rate after the race

Composition profiles of InAs–GaAs quantum dots determined by medium-energy ion scattering

The composition profile along the [001] growth direction of low-growth-rate InAs–GaAs quantum dots (QDs) has been determined using medium-energy ion scattering (MEIS). A linear profile of In concentration from 100% In at the top of the QDs to 20% at their base provides the best fit to MEIS energy spectra

Non-steroidal antiinflammatory drugs fail to enhance healing of acute hamstring injuries treated with physiotherapy

The effects of two non-steroidal anti-inflammatory drugs (NSAIDs), meclofenamate and diclofenac, in combination with physiotherapy modalities on the rate of healing of acute hamstring muscle tears were studied in a doubleblind, placebo-controlled trial. Forty-four of the 75 patients with this injury recruited were assessed and randomly allocated to one of three treatment groups: meclofenamate (100 mg 3 times a day), diclofenac (50 mg 3 times a day) and placebo. All patients received the same intensive physiotherapy treatment over the 7-day treatment period. Patient assessments were performed on days 1, 3 and 7 of the 7-day study period and included pain assessment (visual analogue scale), swelling measurement (thigh circumference measurement at the site of the muscle tear) and isokinetic muscle performance testing. Treatment produced a significant improvement in all measurements in all groups, but there was no difference in any measurement between groups. However, when only the more severe injuries were analysed, the reported pain score at day 7 was significantly lower in the placebo group than in either the  eclofenamate group or the diclofenac group (P < 0,05). Hence this study did not find any additive effect on the healing of acute muscle injuries when meclofenamate or diclofenac was added to standard physiotherapeutic modalities. The study therefore does not support the use of NSAIDs in the treatment of acute hamstring muscle injuries.S Afr Med J 1995; 85: 517-52

Weight loss and attrition in overweight and obese young women during a 36- week internet-based lifestyle intervention

Background: Young women are at high risk of weight gain yet few studies have examined the long-term effectiveness of weight loss programs in this group. This study aimed to investigate the effects of a self-directed internet-based lifestyle program on body weight in young women.Methods: Overweight or obese young women (BMI 33.4 ± 0.3 kg/m2, age 27.8 ± 0.3 years) were initially randomized to General lifestyle advice (G) or Structured lifestyle advice (S) via in-person and website support for 12 weeks (Phase I). After Phase I, all participants were supported through a self-directed internet-based program for 36 weeks (Phase II). The internet-based program included a structured hypocaloric diet, physical activity program, self-monitoring tools, peer group forum and monthly emails. Body weight, energy intake and physical activity were measured at week 0, week 12, week 24 and week 48. Adherence to self-regulatory behaviors was measured at week 48. Mixed model analyses were conducted to determine changes in body weight, energy intake and physical activity.Results: A total of 203 overweight or obese young women commenced Phase I and 130 commenced Phase II. In Phase I, S group had significantly greater weight loss than G group (4.2 ± 0.6 kg vs 0.6 ± 0.3 kg, P<0.001). In Phase II, both groups had significant weight loss over time without significant group differences (-0.8 ± 1.1kg vs -0.8 ± 0.6, P>0.05). Forty-one percent (53/130) of the participants who commenced Phase II completed the internet-based intervention. Dropouts had a higher baseline BMI, were more likely to be married or in a de facto relationship, and more likely to have at least one child.Conclusions: A self-directed internet-based program could be effective in providing support in maintaining weight loss on a structured lifestyle program in young women over 36 weeks. Further research is required to maintain engagement in young women who were married/in a de facto relationship or have children

The structure of epitaxial V2O3 films and their surfaces : a medium energy ion scattering study

Medium energy ion scattering, using 100 keV H+ incident ions, has been used to investigate the growth of epitaxial films, up to thicknesses of ~200 Å, of V2O3 on both Pd(111) and Au(111). Scattered-ion energy spectra provide a measure of the average film thickness and the variations in this thickness, and show that, with suitable annealing, the crystalline quality is good. Plots of the scattering yield as a function of scattering angle, so-called blocking curves, have been measured for two different incidence directions and have been used to determine the surface structure. Specifically, scattering simulations for a range of different model structures show poor agreement with experiment for half-metal (….V’O3V) and vanadyl (….V’O3V=O) terminations, with and without surface interlayer relaxations. However, good agreement with experiment is found for the modified oxygen-termination structure, first proposed by Kresse et al., in which a subsurface V half-metal layer is moved up into the outermost V buckled metal layer to produce a VO2 overlayer on the underlying V2O3, with an associated layer structure of ….O3VV’’V’O3

Anti-inflammatory and combined antiinflammatory/ analgesic medication in the early management of iliotibial band friction syndrome A clinical trial

Forty-three athletes presenting with unilateral iliotibial band friction syndrome (ITBFS) were randomly divided into three groups for the first 7 days of treatment (placebo-controlled, double-blind): 1 - placebo (N = 13); 2 - anti-inflammatory medication (N = 14) (Voharen; Geigy); and 3 - analgesicl anti-inflammatory combined medication (N =. 16) (Myprodol; Rio Ethicals). All subjects rested from day 0 to day 7 and all groups received the same physiotherapy outpatient treatment programme from day 3 to day 7. On days 0, 3 and 7 the subjects performed a functional treadmill running test (maximum 30 minutes) during which they reported pain (scale 0-10; 0 = no pain, 10 = unbearable pain) each minute. Total running distance, total running time and the area under the pain v. time curve was calculated. Daily 24-hour recall pain scores were also recorded. The 24-hour recall pain scores decreased significantly for all the groups over the treatment period. This method of assessing efficacy of treatment therefore failed to show differences between groups. In contrast, during the running test only group 3 improved their total running time and distance from day 0 to day 7, whereas in all the groups the area under the pain v. time curve decreased from day 0 to day 7. All the other groups improved total running time and running distance from day 3 to day 7. All three treatment modalities are effective in the early. treatment of ITBFS but physiotherapy in combination with analgesicl anti-inflammatory medication is superior. A functional running test, which is more sensitive than conventional pain-recall· methods in assessing efficacy of treatment in this type of clinical trial, is described

Differential localization and expression of complement in a rat model of motor neuron disease

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