14,825 research outputs found
Dynamic balance training with sensory electrical stimulation in chronic stroke patients
A case study investigating the impact of sensory electrical stimulation during perturbed stance in one chronic stroke patient is presented. A special apparatus called the BalanceTrainer was used. It allows the application of perturbations to neurologically impaired people during standing, while protecting the subject from falling. The subject underwent two different periods of perturbation training, each lasting ten days. During the first period the subject was perturbed in eight different directions. During the second period the subject was also perturbed, but was assisted by sensory electrical stimulation of the soleus, tibialis anterior, tensor fascia latae, and vastus muscles in the impaired leg. After each period of training an assessment was carried out to measure the forces the subject applied on the ground via two force plates. The subject improved his ability to balance throughout the training, with the largest improvements during the final period when electrical stimulation was used
Recommended from our members
Unbalanced exchange flow and its implications for the night cooling of buildings by displacement ventilation
AbstractPassive ventilation of buildings at night forms an essential part of a low-energy cooling strategy, enabling excess heat that has accumulated during the day to self-purge and be replaced with cooler night air. Instrumental to the success of a purge are the locations and areas of ventilation openings, and openings positioned at low and at high levels are a common choice as there is then the expectation that a buoyancy-driven displacement flow will establish and persist. Desirable for their efficiency, displacement flows guide excess heat out through high-level openings and cooler air in through low-level openings. Herein we show that displacement flow cannot be maintained for the full duration of a purge. Instead, the flow must transition to an ‘unbalanced exchange flow’, whereby the cool inflow of air at low level is maintained but there is now a warm outflow and a cool inflow occurring simultaneously at the high-level opening. The internal redistribution of heat caused by this exchange alters the rate at which heat is self-purged and the time thought necessary to complete a purge. We develop a theoretical model that captures and predicts these behaviours. Our approach is distinct from all others which assume that a displacement flow will persist throughout the purge. Based on this enhanced understanding, and specifically that the transition to unbalanced exchange flow changes the rate of cooling and resultant emptying times, we anticipate that practitioners will be better placed to design passive systems that meet their target specifications for cooling.</jats:p
Spatial patterns of desynchronization bursts in networks
We adapt a previous model and analysis method (the {\it master stability
function}), extensively used for studying the stability of the synchronous
state of networks of identical chaotic oscillators, to the case of oscillators
that are similar but not exactly identical. We find that bubbling induced
desynchronization bursts occur for some parameter values. These bursts have
spatial patterns, which can be predicted from the network connectivity matrix
and the unstable periodic orbits embedded in the attractor. We test the
analysis of bursts by comparison with numerical experiments. In the case that
no bursting occurs, we discuss the deviations from the exactly synchronous
state caused by the mismatch between oscillators
Bifenthrin Baseline Susceptibility and Evaluation of Simulated Aerial Applications in \u3ci\u3eStriacosta albicosta\u3c/i\u3e (Lepidoptera: Noctuidae)
Striacosta albicosta (Smith) is a maize pest that has recently expanded its geographical range into the eastern United States and southeastern Canada. Aerial application of pyrethroids, such as bifenthrin, has been a major practice adopted to manage this pest. Reports of field failure of pyrethroids have increased since 2013. Striacosta albicosta populations were collected in 2016 and 2017 from maize fields in Nebraska, Kansas, and Canada and screened with bifenthrin active ingredient in larval contact dose-response bioassays. Resistance ratios estimated were generally low in 2016 (1.04- to 1.32-fold) with the highest LC50 in North Platte, NE (66.10 ng/cm2) and lowest in Scottsbluff, NE (50.10 ng/cm2). In 2017, O’Neill, NE showed the highest LC50 (100.66 ng/cm2) and Delhi, Canada exhibited the lowest (6.33 ng/cm2), resulting in a resistance ratio variation of 6.02- to 15.90-fold. Implications of bifenthrin resistance levels were further investigated by aerial application simulations. Experiments were conducted with a spray chamber where representative S. albicosta populations were exposed to labeled rates of a commercial bifenthrin formulation. Experiments resulted in 100% mortality for all populations, instars, insecticide rates, and carrier volumes, suggesting that levels of resistance estimated for bifenthrin active ingredient did not seem to impact the efficacy of the correspondent commercial product under controlled conditions. Results obtained from this research indicate that control failures reported in Nebraska could be associated with factors other than insecticide resistance, such as issues with the application technique, environmental conditions during and/or after application, or the insect’s natural behavior. Data generated will assist future S. albicosta resistance management programs
Accessing elite nurses for research: reflections on the theoretical and practical issues of telephone interviewing
Elite groups are interesting as they frequently are powerful (in terms of position, knowledge and influence) and enjoy considerable authority. It is important, therefore, to involve them in research concerned with understanding social contexts and processes. This is particularly pertinent in healthcare, where considerable strategic development and change are features of everyday practice that may be guided or perceived as being guided, by elites.
This paper evolved from a study investigating the availability and role of nurses whose remit involved leading nursing research and development within acute NHS Trusts in two health regions in Southern England. The study design included telephone interviews with Directors of Nursing Services during which time the researchers engaged in a reflective analysis of their experiences of conducting research with an `elite' group. Important issues identified were the role of gatekeepers, engagement with elites and the use of the telephone interview method in this context. The paper examines these issues and makes a case for involving executive nurses in further research. The paper also offers strategies to help researchers design and implement telephone interview studies successfully to maximise access to the views and experiences of `hard to reach groups', such as elites, while minimising the associated disruption
Carotid Intima-Media Thickness Progression in HIV-Infected Adults Occurs Preferentially at the Carotid Bifurcation and Is Predicted by Inflammation.
BackgroundShear stress gradients and inflammation have been causally associated with atherosclerosis development in carotid bifurcation regions. The mechanism underlying higher levels of carotid intima-media thickness observed among HIV-infected individuals remains unknown.Methods and resultsWe measured carotid intima-media thickness progression and development of plaque in the common carotid, bifurcation region, and internal carotid artery in 300 HIV-infected persons and 47 controls. The median duration of follow-up was 2.4 years. When all segments were included, the rate of intima-media thickness progression was greater in HIV-infected subjects compared with controls after adjustment for traditional risk factors (0.055 vs. 0.024 mm/year, P=0.016). Rate of progression was also greater in the bifurcation region (0.067 vs. 0.025 mm/year, P=0.042) whereas differences were smaller in the common and internal regions. HIV-infected individuals had a greater incidence of plaque compared with controls in the internal (23% vs. 6.4%, P=0.0037) and bifurcation regions (34% vs. 17%, P=0.014). Among HIV-infected individuals, the rate of progression in the bifurcation region was more rapid compared with the common carotid, internal, or mean intima-media thickness; in contrast, progression rates among controls were similar at all sites. Baseline hsCRP was elevated in HIV-infected persons and was a predictor of progression in the bifurcation region.ConclusionsAtherosclerosis progresses preferentially in the carotid bifurcation region in HIV-infected individuals. hsCRP, a marker of inflammation, is elevated in HIV and is associated with progression in the bifurcation region. These data are consistent with a model in which the interplay between hemodynamic shear stresses and HIV-associated inflammation contribute to accelerated atherosclerosis. (J Am Heart Assoc. 2012;1:jah3-e000422 doi: 10.1161/JAHA.111.000422.)Clinical trial registrationURL: http://clinicaltrials.gov. Unique identifier: NCT01519141
Recommended from our members
The effect of soil moisture perturbations on Indian Monsoon Depressions in a numerical weather prediction model
Indian monsoon depressions (MDs) are synoptic-scale cyclonic systems that propagate across peninsular India three or four times per monsoon season. They are responsible for the majority of rainfall in agrarian north India, thus constraining precipitation estimates is of high importance. Here, we use a case study from August 2014 to explore the relationship between varying soil moisture and the resulting track and structure of an incident MD using the Met Office Unified Model. We use this case study with the view to increasing understanding of the general impact of soil moisture perturbations on monsoon depressions. It is found that increasing soil moisture in the monsoon trough region results in deeper inland penetration and a more developed structure - e.g. a warmer core in the mid-troposphere and a stronger bimodal potential vorticity core in the middle/lower troposphere - with more precipitation, and a
structure that in general more closely resembles that found in depressions over the ocean, indicating that soil moisture may enhance the convective mechanism that drives depressions over land. This experiment also shows that these changes are most significant when the depression is deep, and negligible when it is weakening. Increasing soil moisture in the sub-Himalayan arable zone, a region with large irrigation coverage, also caused deeper inland penetration and some feature enhancement in the upper troposphere but no significant changes were found in the track heading or lower-tropospheric structure
Fluid flow at the interface between elastic solids with randomly rough surfaces
I study fluid flow at the interface between elastic solids with randomly
rough surfaces. I use the contact mechanics model of Persson to take into
account the elastic interaction between the solid walls and the Bruggeman
effective medium theory to account for the influence of the disorder on the
fluid flow. I calculate the flow tensor which determines the pressure flow
factor and, e.g., the leak-rate of static seals. I show how the perturbation
treatment of Tripp can be extended to arbitrary order in the ratio between the
root-mean-square roughness amplitude and the average interfacial surface
separation. I introduce a matrix D(Zeta), determined by the surface roughness
power spectrum, which can be used to describe the anisotropy of the surface at
any magnification Zeta. I present results for the asymmetry factor Gamma(Zeta)
(generalized Peklenik number) for grinded steel and sandblasted PMMA surfaces.Comment: 16 pages, 14 figure
Mangarara Formation: exhumed remnants of a middle Miocene, temperate carbonate, submarine channel-fan system on the eastern margin of Taranaki Basin, New Zealand
The middle Miocene Mangarara Formation is a thin (1–60 m), laterally discontinuous unit of moderately to highly calcareous (40–90%) facies of sandy to pure limestone, bioclastic sandstone, and conglomerate that crops out in a few valleys in North Taranaki across the transition from King Country Basin into offshore Taranaki Basin. The unit occurs within hemipelagic (slope) mudstone of Manganui Formation, is stratigraphically associated with redeposited sandstone of Moki Formation, and is overlain by redeposited volcaniclastic sandstone of Mohakatino Formation. The calcareous facies of the Mangarara Formation are interpreted to be mainly mass-emplaced deposits having channelised and sheet-like geometries, sedimentary structures supportive of redeposition, mixed environment fossil associations, and stratigraphic enclosure within bathyal mudrocks and flysch. The carbonate component of the deposits consists mainly of bivalves, larger benthic foraminifers (especially Amphistegina), coralline red algae including rhodoliths (Lithothamnion and Mesophyllum), and bryozoans, a warm-temperate, shallow marine skeletal association. While sediment derivation was partly from an eastern contemporary shelf, the bulk of the skeletal carbonate is inferred to have been sourced from shoal carbonate factories around and upon isolated basement highs (Patea-Tongaporutu High) to the south. The Mangarara sediments were redeposited within slope gullies and broad open submarine channels and lobes in the vicinity of the channel-lobe transition zone of a submarine fan system. Different phases of sediment transport and deposition (lateral-accretion and aggradation stages) are identified in the channel infilling. Dual fan systems likely co-existed, one dominating and predominantly siliciclastic in nature (Moki Formation), and the other infrequent and involving the temperate calcareous deposits of Mangarara Formation. The Mangarara Formation is an outcrop analogue for middle Miocene-age carbonate slope-fan deposits elsewhere in subsurface Taranaki Basin, New Zealand
Point of care blood tests during home visits by out-of-hours primary care clinicians; a mixed methods evaluation of a service improvement
Objectives We aimed to evaluate test usage and patient and clinician experience following the introduction of point-of-care (POC) blood tests into a primary care out-of-hours service.
Design A mixed methods service evaluation comprising quantitative records of the clinical contexts of tests taken and qualitative interviews with clinicians. Research permissions and governance were obtained for patient interviews.
Setting Out-of-hours primary care.
Participants All patients requiring home visits from the service during the implementation period.
Interventions The i-STAT POC blood test platform was introduced to two bases providing home visits for a period of 8 months. Venous blood samples were used and two cartridges were available. The CHEM8 cartridge measures sodium, potassium, chloride, total carbon dioxide (TCO2), anion gap, ionised calcium, glucose, urea, creatinine, haematocrit and haemoglobin. The CG4 cartridge measures lactate, pH, PaO2 and PCO2, TCO2, bicarbonate, base excess and oxygen saturation.
Primary and secondary outcome measures The proportion of home visits where tests were taken, the clinical contexts of those tests, the extent to which clinicians felt the tests had influenced their decisions, time taken to perform the test and problems encountered. Clinician and patient experiences of using POC tests.
Results i-STAT POC tests were infrequently used, with successful tests taken at just 47 contacts over 8 months of implementation. The patients interviewed felt that testing had been beneficial for their care. Clinician interviews suggested barriers to POC tests, including practical challenges, concerns about time, doubt over whether they would improve clinical decision making and concern about increased medicolegal risk. Suggestions for improving adoption included sharing learning, adopting a whole team approach and developing protocols for usage.
Conclusions POC tests were not successfully adopted by an out-of-hours home visiting service in Oxfordshire. While some clinicians felt they could not add value, in other cases they resulted in improved patient experience. Adoption could be promoted by improving technical, team and education factors
- …