We present a phenomenological model for granular suspension rheology in which particle interactions enter as constraints to relative particle motion. By considering constraints that are formed and ...released by stress respectively, we derive a range of experimental flow curves in a single treatment and predict singularities in viscosity and yield stress consistent with literature data. Fundamentally, we offer a generic description of suspension flow that is independent of bespoke microphysics.
Inappropriate disposal of plastic debris has led to the contamination of marine habitats worldwide. This debris can be ingested by organisms; however, the extent to which chewing and gut transit ...modifies plastic debris is unclear. Detritivores, such as amphipods, ingest and shred natural organic matter and are fundamental to its breakdown. Here we examine ingestion and shredding of plastic carrier bags by Orchestia gammarellus. A laboratory experiment showed these amphipods shredded plastic carrier bags, generating numerous microplastic fragments (average diameter 488.59μm). The presence of a biofilm significantly increased the amount of shredding, but plastic type (conventional, degradable and biodegradable) had no effect. Subsequent field observations confirmed similar shredding occurred on the strandline. Rates of shredding will vary according to amphipod density; however, our data indicates that shredding by organisms could substantially accelerate the formation microplastics in the environment.
•An experimental study testing the effect of biofilms and plastic type on plastic bag biodegradation by O. gammarellus.•O. gammarellus shreds plastic carrier bags generating numerous pieces of microplastic (488.59μm average diameter).•Fouling significantly increased the amount of plastic shredded producing an average 8.23 fragments/amphipod/day.•Plastic type had no effect on the amount shredded.•Subsequent field observations confirmed the shredding of plastic carrier-bags in the field.
Purpose
To use the World Health Organisation’s International Classification of Functioning to measure disability following critical illness using patient-reported outcomes.
Methods
A prospective, ...multicentre cohort study conducted in five metropolitan intensive care units (ICU). Participants were adults who had been admitted to the ICU, received more than 24 h of mechanical ventilation and survived to hospital discharge. The primary outcome was measurement of disability using the World Health Organisation’s Disability Assessment Schedule 2.0. The secondary outcomes included the limitation of activities and changes to health-related quality of life comparing survivors with and without disability at 6 months after ICU.
Results
We followed 262 patients to 6 months, with a mean age of 59 ± 16 years, and of whom 175 (67%) were men. Moderate or severe disability was reported in 65 of 262 (25%). Predictors of disability included a history of anxiety/depression odds ratio (OR) 1.65 (95% confidence interval (CI) 1.22, 2.23),
P
= 0.001; being separated or divorced OR 2.87 (CI 1.35, 6.08),
P
= 0.006; increased duration of mechanical ventilation OR 1.04 (CI 1.01, 1.08),
P
= 0.03 per day; and not being discharged to home from the acute hospital OR 1.96 (CI 1.01, 3.70)
P
= 0.04. Moderate or severe disability at 6 months was associated with limitation in activities, e.g. not returning to work or studies due to health (
P
< 0.002), and reduced health-related quality of life (
P
< 0.001).
Conclusion
Disability measured using patient-reported outcomes was prevalent at 6 months after critical illness in survivors and was associated with reduced health-related quality of life. Predictors of moderate or severe disability included a prior history of anxiety or depression, separation or divorce and a longer duration of mechanical ventilation.
Trial registration: NCT02225938.
► Runoff was projected from 15 GCMs and three warming levels over south-western Australia. ► All GCMs project a drier and hotter future in south-western Australia by 2030. ► An ensemble of ...rainfall-runoff models projects a median decline in runoff of 25%. ► 90th percentile projected runoff declines 53% in the north and 40% in the south of the project area. ► Rainfall-runoff elasticity increases under projected climate scenarios.
This paper presents the results of computer simulations of runoff from 13 major fresh and brackish river basins in south-western Australia (SWA) under climate projections obtained from 15 GCMs with three future global warming scenarios equivalent to global temperature rises of 0.7°C, 1.0°C and 1.3°C by 2030. The objective was to apply an efficient methodology, consistent across a large region, to examine the implications of the best available projections in climate trends for future surface water resources. An ensemble of rainfall-runoff models was calibrated on stream flow data from 1975 to 2007 from 106 gauged catchments distributed throughout the basins of the study area. The sensitivity of runoff to projected changes in mean annual rainfall is examined using the climate ‘elasticity’ concept. Averaged across the study area, all 15 GCMs project declines in rainfall under all global warming scenarios with a median decline of 8% resulting in a median decline in runoff of 25%. Such uniformity in projections from GCMs is unusual. Over SWA the average annual runoff under the 5th wettest and 5th driest of the 45 projections of the 2030 climate declines by 10 and 42%, respectively. Under the 5th driest projection the runoff decline ranges from 53% in the northern region to 40% in the southern region. Strong regional variations in climate sensitivity are found with the proportional decline in runoff greatest in the northern region and the greatest volumetric declines in the wetter basins in the south. Since the mid 1970s stream flows into the major water supply reservoirs in SWA have declined by more than 50% following a 16% rainfall reduction. This has already had major implications for water resources planning and for the preservation of aquatic and riparian ecosystems in the region. Our results indicate that this reduction in runoff is likely to continue if future climate projections eventuate.
Different species and genotypes of Miscanthus were analysed to determine the influence of genotypic variation and harvest time on cell wall composition and the products which may be refined via ...pyrolysis. Wet chemical, thermo-gravimetric (TGA) and pyrolysis-gas chromatography–mass spectrometry (Py-GC–MS) methods were used to identify the main pyrolysis products and determine the extent to which genotypic differences in cell wall composition influence the range and yield of pyrolysis products. Significant genotypic variation in composition was identified between species and genotypes, and a clear relationship was observed between the biomass composition, yields of pyrolysis products, and the composition of the volatile fraction. Results indicated that genotypes other than the commercially cultivated Miscanthus x giganteus may have greater potential for use in bio-refining of fuels and chemicals and several genotypes were identified as excellent candidates for the generation of genetic mapping families and the breeding of new genotypes with improved conversion quality characteristics.
The aim of the present study was to evaluate “flushable” and “non-flushable” wet wipes as a source of plastic pollution in the River Thames at Hammersmith, London and the impacts they have on the ...invasive Asian clam, Corbicula fluminea, in this watercourse. Surveys were conducted to assess whether the density of wet wipes along the foreshore upstream of Hammersmith Bridge affected the distribution of C. fluminea. High densities of wet wipes were associated with low numbers of clams and vice versa. The maximum wet wipe density recorded was 143 wipes m−2 and maximum clam density 151 individuals m−2. Clams adjacent to the wet wipe reefs were found to contain synthetic polymers including polypropylene (57%), polyethylene (9%), polyallomer (8%), nylon (8%) and polyester (3%). Some of these polymers may have originated from the wet wipe reefs.
Display omitted
•Large accumulations of wet wipes are described on the foreshore of the River Thames.•Wet wipes are originating from local sewerage outfalls.•High densities of wet wipes are associated with low numbers of Asian clams.•Clam tissue was digested in 10% KOH solution to reveal microplastic contamination.•Synthetic fibres ingested by Asian clams are potentially released from wet wipes.
Demands are growing rapidly in the operational prediction and applications communities for forecasts that fill the gap between medium-range weather and long-range or seasonal forecasts. Based on the ...potential for improved forecast skill at the subseasonal to seasonal time range, the Subseasonal to Seasonal (S2S) Prediction research project has been established by the World Weather Research Programme/World Climate Research Programme. A main deliverable of this project is the establishment of an extensive database containing subseasonal (up to 60 days) forecasts, 3 weeks behind real time, and reforecasts from 11 operational centers, modeled in part on the The Observing System Research and Predictability Experiment (THORPEX) Interactive Grand Global Ensemble (TIGGE) database for medium-range forecasts (up to 15 days).
The S2S database, available to the research community since May 2015, represents an important tool to advance our understanding of the subseasonal to seasonal time range that has been considered for a long time as a “desert of predictability.” In particular, this database will help identify common successes and shortcomings in the model simulation and prediction of sources of subseasonal to seasonal predictability. For instance, a preliminary study suggests that the S2S models significantly underestimate the amplitude of the Madden–Julian oscillation (MJO) teleconnections over the Euro-Atlantic sector. The S2S database also represents an important tool for case studies of extreme events. For instance, a multimodel combination of S2S models displays higher probability of a landfall over the islands of Vanuatu 2–3 weeks before Tropical Cyclone Pam devastated the islands in March 2015.
Retraining the injured spinal cord Edgerton, V. R.; Leon, R. D.; Harkema, S. J. ...
The Journal of physiology,
05/2001, Letnik:
533, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The present review presents a series of concepts that may be useful in developing rehabilitative strategies to enhance recovery
of posture and locomotion following spinal cord injury. First, the loss ...of supraspinal input results in a marked change in
the functional efficacy of the remaining synapses and neurons of intraspinal and peripheral afferent (dorsal root ganglion)
origin. Second, following a complete transection the lumbrosacral spinal cord can recover greater levels of motor performance
if it has been exposed to the afferent and intraspinal activation patterns that are associated with standing and stepping.
Third, the spinal cord can more readily reacquire the ability to stand and step following spinal cord transection with repetitive
exposure to standing and stepping. Fourth, robotic assistive devices can be used to guide the kinematics of the limbs and
thus expose the spinal cord to the new normal activity patterns associated with a particular motor task following spinal cord
injury. In addition, such robotic assistive devices can provide immediate quantification of the limb kinematics. Fifth, the
behavioural and physiological effects of spinal cord transection are reflected in adaptations in most, if not all, neurotransmitter
systems in the lumbosacral spinal cord. Evidence is presented that both the GABAergic and glycinergic inhibitory systems are
up-regulated following complete spinal cord transection and that step training results in some aspects of these transmitter
systems being down-regulated towards control levels. These concepts and observations demonstrate that (a) the spinal cord
can interpret complex afferent information and generate the appropriate motor task; and (b) motor ability can be defined to
a large degree by training.
Purpose
This study aimed to determine the prevalence and predictors of death or new disability following critical illness.
Methods
Prospective, multicentre cohort study conducted in six metropolitan ...intensive care units (ICU). Participants were adults admitted to the ICU who received more than 24 h of mechanical ventilation. The primary outcome was death or new disability at 6 months, with new disability defined by a 10% increase in the WHODAS 2.0.
Results
Of 628 patients with the primary outcome available (median age of 62 49–71 years, 379 61.0% had a medical admission and 370 (58.9%) died or developed new disability by 6 months. Independent predictors of death or new disability included age OR 1.02 (1.01–1.03),
P
= 0.001, higher severity of illness (APACHE III) OR 1.02 (1.01–1.03),
P
< 0.001 and admission diagnosis. Compared to patients with a surgical admission diagnosis, patients with a cardiac arrest OR (95% CI) 4.06 (1.89–8.68),
P
< 0.001, sepsis OR (95% CI) 2.43 (1.32–4.47),
P
= 0.004, or trauma OR (95% CI) 6.24 (3.07–12.71),
P
< 0.001 diagnosis had higher odds of death or new disability, while patients with a lung transplant OR (95% CI) 0.21 (0.07–0.58),
P
= 0.003 diagnosis had lower odds. A model including these three variables had good calibration (Brier score 0.20) and acceptable discriminative power with an area under the receiver operating characteristic curve of 0.76 (95% CI 0.72–0.80).
Conclusion
Less than half of all patients mechanically ventilated for more than 24 h were alive and free of new disability at 6 months after admission to ICU. A model including age, illness severity and admission diagnosis has acceptable discriminative ability to predict death or new disability at 6 months.
PDF
