Adjoint error estimation and spatial adaptivity for EHL-like models

The use of adjoint error estimation techniques is described for a model problem that is a simplified version of an EHL line contact. Quantities of interest, such as friction, may be dependent upon the accuracy of the Solution in some parts of the domain more than in others. The use of an inexpensive extra solve to calculate an adjoint solution is described for estimating the intergrid error in the value of friction calculated, and as a basis for local refinement. It is demonstrated that this enables an accurate estimate for the quantity of interest to be obtained from a less accurate solution of the model problem

Wall Adhesion and Constitutive Modelling of Strong Colloidal Gels

Wall adhesion effects during batch sedimentation of strongly flocculated colloidal gels are commonly assumed to be negligible. In this study in-situ measurements of colloidal gel rheology and solids volume fraction distribution suggest the contrary, where significant wall adhesion effects are observed in a 110mm diameter settling column. We develop and validate a mathematical model for the equilibrium stress state in the presence of wall adhesion under both viscoplastic and viscoelastic constitutive models. These formulations highlight fundamental issues regarding the constitutive modeling of colloidal gels, specifically the relative utility and validity of viscoplastic and viscoelastic rheological models under arbitrary tensorial loadings. The developed model is validated against experimental data, which points toward a novel method to estimate the shear and compressive yield strength of strongly flocculated colloidal gels from a series of equilibrium solids volume fraction profiles over various column widths.Comment: 37 pages, 12 figures, submitted to Journal of Rheolog

Characteristics of torque production of the lower limb are significantly altered after 2 hours of treadmill load carriage

Load carriage is seldom completed in isolation, meaning load bearers need to be physically capable of physical activity after the load carriage task. This study aims to examine changes in lower limb muscle strength, as measured by torque production across a range of joint angles as a result of prolonged load carriage. Thirty-four healthy participants underwent two hours of loaded or unloaded treadmill load carriage, with lower limb muscle function variables assessed pre and post activity. The loaded group had a mass of (Mean(range)) 76.45 (27.12)kg, stature: 178.56 (17.63)cm, age: 23(6)yrs, and comprised of 13 males and 3 females. While the unloaded group had a body mass of 73.69(24.19)kg, stature: 178.89(18.49)cm, age: 22(5)yrs and comprised of 14 males and 4 females. Significant reductions across a range of parameters were observed. Characterised by reductions at the optimum muscle length for torque output, with all aspects demonstrating large (knee extension at 180˚·s-1: 0.51 Standardised SD, knee extnsion at 60˚·s-1: 0.98 standardised SD) or extremely large individual differences (knee flexion at 180˚·s-1: 2.17 standardised SD). These findings suggest after the completion of the load carriage task participants are in a significantly reduced physical state, which may have implications for secondary tasks

Maternal IQ Predicts Child's Birth Weight

poster abstractBackground: Prior studies correlated birth weight with child IQ. Maternal IQ correlates with IQ in her offspring. Birth weight predicted IQ in monozygotic twins dicordant for birth weight. IUGR alters global DNA methylation. IQ in mother may be a biological marker for her child's rate of intrauterine growth (birth weight). Objective: Does maternal IQ predict her child's intrauterine growth rate (birth weight)? Design/Methods: Births from 1970-2004 using NLSY '79 database were studied Primary variables were children's IQ score from most recent Peabody Picture Vocabulary Revised Form L test and birth weight in grams. Maternal IQ was estimated from AirForce Qualifying test (AFQT)and categorized as 75, 50-74, 25-49 and <25%ile resp. Race, economic status, singleton, gestation, use of tobacco, alcohol and other drugs were used as covariates. Multivariate models were used to assess associations of Children's IQ and birth weight with maternal IQ levels controlling for other covariates. Results: 9,125 children were analyzed. 98.3% singleton, 12.3% preterm, and 51.2% male. Means Std's of birth weight and IQ score were 3,307 597 grams and 38 30.4 respectively.Of the total 4,121 mothers, 25.7% were blacks, 18.3% were Hispanics and 54.0% were non Hispanic non blacks(nHnB). The mean std of the AFQT was 36.9 28.1. Proportions of IQs were 13.6%, 17.2%, 27.2% and 42% from low to high IQs respectively among mothers. Multivariate models showed children's IQ scores were related to their mother's IQ ,birth weight, race/ethnicity, and economic status. In particular, the mean children's IQ scores were 28.1, 37.1, 46.8, and 55 at mother's IQ levels from low to high respectively (p-values<0.001). Children's IQs was increased by 0.14 0.06 (slope) for every 100 gram increase in birth weight (p=0.013). Children's birth weights were positively associated with their mothers' IQ. Means birth weight increased from 3,334 grams to 3,465 grams as mothers' IQ rose from low to high (p<0.001). When sub-populations stratified by race/ethnicity were analyzed, positive relationships between childs IQ and mother's IQ were found in all Hispanic, black and nHnB groups (p's<0.001); while the positive relationship between birth weight and mother's IQ levels was found significant only in the nHnB (white) group (p<0.001). The findings held even after preterm and non singleton births were excluded from analysis. Conclusions: Child's IQ correlates with birth weight and maternal IQ. Maternal IQ may also predict birth weight of offspring

Statin therapy in critical illness : an international survey of intensive care physicians' opinions, attitudes and practice

Background Pleotropic effects of statins on inflammation are hypothesised to attenuate the severity of and possibly prevent the occurrence of the host inflammatory response to pathogen and infection-related acute organ failure. We conducted an international survey of intensive care physicians in Australia, New Zealand (ANZ) and United Kingdom (UK). The aims of the survey were to assess the current prescribing practice patterns, attitudes towards prescribing statin therapy in critically ill patients and opinions on the need for an interventional trial of statin therapy in critically ill patients. Methods Survey questions were developed through an iterative process. An expert group reviewed the resulting 26 items for face and content validity and clarity. The questions were further refined following pilot testing by ICU physicians from Australia, Canada and the UK. We used the online Smart SurveyTM software to administer the survey. Results Of 239 respondents (62 from ANZ and 177 from UK) 58% worked in teaching hospitals; most (78.2%) practised in ‘closed’ units with a mixed medical and surgical case mix (71.0%). The most frequently prescribed statins were simvastatin (77.6%) in the UK and atorvastatin (66.1%) in ANZ. The main reasons cited to explain the choice of statin were preadmission prescription and pharmacy availability. Most respondents reported never starting statins to prevent (65.3%) or treat (89.1%) organ dysfunction. Only a minority (10%) disagreed with a statement that the risks of major side effects of statins when prescribed in critically ill patients were low. The majority (84.5%) of respondents strongly agreed that a clinical trial of statins for prevention is needed. More than half (56.5%) favoured rates of organ failure as the primary outcome for such a trial, while a minority (40.6%) favoured mortality. Conclusions Despite differences in type of statins prescribed, critical care physicians in the UK and ANZ reported similar prescription practices. Respondents from both communities agreed that a trial is needed to test whether statins can prevent the onset of new organ failure in patients with sepsis

Millimeter Wave Localization: Slow Light and Enhanced Absorption

We exploit millimeter wave technology to measure the reflection and transmission response of random dielectric media. Our samples are easily constructed from random stacks of identical, sub-wavelength quartz and Teflon wafers. The measurement allows us to observe the characteristic transmission resonances associated with localization. We show that these resonances give rise to enhanced attenuation even though the attenuation of homogeneous quartz and Teflon is quite low. We provide experimental evidence of disorder-induced slow light and superluminal group velocities, which, in contrast to photonic crystals, are not associated with any periodicity in the system. Furthermore, we observe localization even though the sample is only about four times the localization length, interpreting our data in terms of an effective cavity model. An algorithm for the retrieval of the internal parameters of random samples (localization length and average absorption rate) from the external measurements of the reflection and transmission coefficients is presented and applied to a particular random sample. The retrieved value of the absorption is in agreement with the directly measured value within the accuracy of the experiment.Comment: revised and expande

A 4-week resistance training intervention improves stability, strength and neuromuscular activity in the lower limb: a case study of a cerebral palsy adult

Spastic diplegia, a form of cerebral palsy, is a neurological disorder that results in some degree of spasticity. It is often associated with impairment of both normal and selective movement of the lower limbs, and some degree of muscular weakness. Resistance training is an established exercise intervention with numerous neurological benefits. Evidence suggests that resistance training can positively improve stability in young populations with cerebral palsy. However, little research exists in adult populations, who are at greater risk of inactivity due to ageing and an increase in sedentarism. A single-subject (aged 35-years old, 150.5 centimetres, 81 kilograms) case-study was therefore carried out to investigate the effectiveness of a 4-week resistance training intervention on stability, neuromuscular activity and force output in a male adult with cerebral palsy. The variables measured were total centre of pressure displacement, peak torque in both the quadriceps and hamstrings and Surface Electromyography (sEMG) activity in the Rectus Femoris (RF), Vastus Lateralis (VL), Biceps Femoris (BF) and Semitendinosus (ST). The results demonstrated that a 4-week resistance training intervention reduced total centre of pressure displacement (-51.34%) whilst concomitantly increased sEMG output (RF left +80% right +22%, VL left +160% right +26%, BF left +203% right +44%, ST left +40% right +90%) and peak torque values (right leg extension -7%, right leg flexion +29%, left leg extension +11%, left leg flexion +42%). In conclusion, this case study demonstrates that a 4-week resistance training intervention improves the stability of the participant, possibly through neurological adaptations and improvements to lower limb strength

Centre of pressure, vertical ground reaction forces and neuromuscular responses of special-forces soldiers to 43km load carriage in the field

The primary purpose of this study was to examine lateral deviations in centre of pressure as a result of an extreme duration load carriage task, with particular focus on heel contact. Twenty (n=17 males, n=3 females) soldiers from a Special Operation Forces unit (body mass: 80.72±21.49kg; stature:178.25±8.75cm; age: 26±9yrs) underwent gait plantar pressure assessment and vertical jump testing before and after a 43km load carriage event (duration 817.02[32.66]min) carrying a total external load of 29.80 (1.05)kg. Vertical jump height decreased by 18.62%±16.85% (0.30±0.08m to 0.24±0.07m) p<.001. Loading peak and mid stance force minimum were significantly increased after load carriage (2.59±0.51BW vs. 2.81±0.61BW; p=.035; dGlass=0.44 and 1.28±0.40BW vs. 1.46±0.41BW; p=.015 dGlass=0.45, respectively) and increases in lateral centre of pressure displacement were observed as a result of the load carriage task 14.64±3.62mm to 16.97 ±3.94mm p<.029. In conclusion, load carriage instigated a decrease in neuromuscular function alongside increases in ground reaction forces associated with injury risk and centre of pressure changes associated with ankle sprain risk. Practitioners should consider that possible reduction in ankle stability remains even once the load had been removed, suggesting soldiers are still at increased risk of injury even once the load has been removed

Outcomes of interfacility critical care adult patient transport: a systematic review

INTRODUCTION: We aimed to determine the adverse events and important prognostic factors associated with interfacility transport of intubated and mechanically ventilated adult patients. METHODS: We performed a systematic review of MEDLINE, CENTRAL, EMBASE, CINAHL, HEALTHSTAR, and Web of Science (from inception until 10 January 2005) for all clinical studies describing the incidence and predictors of adverse events in intubated and mechanically ventilated adult patients undergoing interfacility transport. The bibliographies of selected articles were also examined. RESULTS: Five studies (245 patients) met the inclusion criteria. All were case-series and two were prospective in design. Due to the paucity of studies and significant heterogeneity in study population, outcome events, and results, we synthesized data in a qualitative manner. Pre-transport severity of illness was reported in only one study. The most common indication for transport was a need for investigations and/or specialist care (three studies, 220 patients). Transport modalities included air (fixed or rotor wing; 66% of patients) and ground (31%) ambulance, and commercial aircraft (3%). Transport teams included a physician in three studies (220 patients). Death during transfer was rare (n = 1). No other adverse events or significant therapeutic interventions during transport were reported. One study reported a 19% (28/145) incidence of respiratory alkalosis on arrival and another study documented a 30% overall intensive care unit mortality, while no adverse events or outcomes were reported after arrival in the three other studies. CONCLUSION: Insufficient data exist to draw firm conclusions regarding the mortality, morbidity, or risk factors associated with the interfacility transport of intubated and mechanically ventilated adult patients. Further study is required to define the risks and benefits of interfacility transfer in this patient population. Such information is important for the planning and allocation of resources related to transporting critically ill adults