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The role that vitamin D plays in pulmonary function remains uncertain. Epidemiological studies reported mixed findings for serum 25-hydroxyvitamin D (25(OH)D)–pulmonary function association. We conducted the largest cross-sectional meta-analysis of the 25(OH)D–pulmonary function association to date, based on nine European ancestry (EA) cohorts (n 22 838) and five African ancestry (AA) cohorts (n 4290) in the Cohorts for Heart and Aging Research in Genomic Epidemiology Consortium. Data were analysed using linear models by cohort and ancestry. Effect modification by smoking status (current/former/never) was tested. Results were combined using fixed-effects meta-analysis. Mean serum 25(OH)D was 68 (sd 29) nmol/l for EA and 49 (sd 21) nmol/l for AA. For each 1 nmol/l higher 25(OH)D, forced expiratory volume in the 1st second (FEV1) was higher by 1·1 ml in EA (95 % CI 0·9, 1·3; P<0·0001) and 1·8 ml (95 % CI 1·1, 2·5; P<0·0001) in AA (Prace difference=0·06), and forced vital capacity (FVC) was higher by 1·3 ml in EA (95 % CI 1·0, 1·6; P<0·0001) and 1·5 ml (95 % CI 0·8, 2·3; P=0·0001) in AA (Prace difference=0·56). Among EA, the 25(OH)D–FVC association was stronger in smokers: per 1 nmol/l higher 25(OH)D, FVC was higher by 1·7 ml (95 % CI 1·1, 2·3) for current smokers and 1·7 ml (95 % CI 1·2, 2·1) for former smokers, compared with 0·8 ml (95 % CI 0·4, 1·2) for never smokers. In summary, the 25(OH)D associations with FEV1 and FVC were positive in both ancestries. In EA, a stronger association was observed for smokers compared with never smokers, which supports the importance of vitamin D in vulnerable populations.
Introduction: Recruitment and retention of healthcare staff are difficult in rural communities. Poor quality of work life (QWL) may be an underling factor as rural healthcare professionals are often isolated and work with limited resources. However, QWL data on rural emergency (ED) staff is limited. We assessed QWL among nurses and physicians as part of an ongoing study on ED care in Québec. Methods: We selected EDs offering 24/7 medical coverage, with hospitalization beds, in rural or small towns (Stats Canada definition). Of Québec’s 26 rural EDs, 23 (88%) agreed to participate. The online Quality of Work Life Systemic Inventory (QWLSI, with 1 item per 34 “life domains”), was sent to all non-locum ED nurses and physicians (about 500 potential participants). The QWLSI is used for comparing QWL scores to those of a large international database. We present overall and subscale QWL scores as percentiles (PCTL) of scores in the large database, and comparisons of nurses’ and physicians’ scores (t test). Results: Thirty-three physicians and 84 nurses participated. Mean age was 39.8 years (SD=10.1): physicians=37 (7.7) and nurses=40.9 (10.7). Overall QWL scores for all were in the 32nd PCTL, i.e. low. Nurses were in the 28th PCTL and physicians in the 44nd (p>0.05). For both groups, QWL was below the 25th PCTL i.e. very low, for “sharing workload during absence of an employee”, “working equipment”, “flexibility of work schedule”, “impact of working hours on health”, “possibility of being absent for familial reasons”, “relations with employees”. The groups differed (p<0.05) on only two subscales: remuneration and career path. For remuneration, scores were similar on fringe benefits (nurses 22nd PCTL, physicians 32nd) and income security (nurses 72nd, physicians 74th), but differed on income level (nurses 74th, physicians 93rd). The groups differed on all 3 career path items: advancement possibilities (nurses 53th, physicians 91st), possibilities for transfer (nurses 51nd, physicians 84th) and continuing education (nurses 18th, physicians 49th). Conclusion: Overall QWL among rural ED staff is poor. Groups had similar QWL scores except on career path, with physicians perceiving better long-term prospects. Given difficulties in rural recruitment and retention, these findings suggest that QWL should be assessed in rural and urban EDs nationwide.
Introduction: Decreasing readmission rates and return emergency department (ED) visits represent a major challenge for health organizations. Seniors are especially vulnerable to discharge adverse events which can result in unplanned readmissions and loss of physical, functional and/or cognitive capacity. The ACE Collaborative is a national quality improvement initiative that aims to improve care of elderly patients. We aimed to adapt Mount Sinai’s Care Transitions program to our local context in order to decrease avoidable readmissions and ED visits among seniors. Methods: We performed a prospective pre/post implementation cohort study. We recruited frail elderly hospitalized patients (≥50 years old) discharged to home and at risk of readmission (modified LACE index score≥7/12). We excluded patients being discharged to long-term nursing homes or institutions. Our intervention is based on selected strategic ACE Care Transitions best practices: transition coach, telehealth personal response services and a structured discharge checklist. The intervention is offered to selected patients before hospital discharge. Our primary outcome is a 30-day post-discharge composite of hospital readmission and return ED visit rate. Our secondary outcomes are functional autonomy, satisfaction with care transition, quality of life, caregiver strain and healthcare resource use at recruitment and at 30-days follow-up. Hospital-level administrative data is also collected to measure global effect of practice changes. Results: The project is currently ongoing and preliminary results are available for the pre-implementation cohort only. Patients in this cohort (n=33) were mainly men (61%), aged 75±10 years and presented an OARS score (Activities of Daily Living instrument that ranges from 0-28) of 5.6±4.9. At 30 days post-discharge, the patients in our cohort had a 42.4% readmission rate (14 hospitalisations) and a 54.5% return ED visit rate (18 visits). For the same time period, readmission and return ED rates for all patients in the same corresponding age-group at the hospital level were 14.4% and 21.9%, respectively. Further results for our post-intervention cohort will be presented at CAEP 2017. Conclusion: Our cohort of elderly patients have high readmission and return ED visit rates. Our ongoing quality improvement project aims to decrease these readmissions and ED visits.
Introduction: Trauma remains the primary cause of death in people under 40 in Québec. Although trauma care has dramatically improved in the last decade, no empirical data on the effectiveness of trauma care in rural Québec are available. This study aims to establish a portrait of trauma and trauma-related mortality in rural versus urban pre-hospital and hospital settings. Methods: Data for all trauma victims treated in the 26 rural hospitals and 32 Level-1 and Level-2 urban trauma centres was obtained from Québec’s trauma registry (2009-2013). Rural hospitals were located in rural small towns (Statistics Canada definition), provided 24/7 physician coverage and admission capabilities. Study population was trauma patients who accessed eligible hospitals. Transferred patients were excluded. Descriptive statistics were used to compare rural with urban trauma case frequency, severity and mortality and descriptive data collected on emergency department (ED) characteristics. Using logistic regression analysis we compared rural to urban in-hospital mortality (pre-admission and during ED stay), adjusting for age, sex, severity (ISS), injury type and mode of transport. Results: Rural hospitals (N=26) received on average 490 000 ED visits per year and urban trauma centres (N=32), 1 550 000. Most rural hospitals had 24/7 coverage and diagnostic equipment e.g. CT scanners (74 %), intensive care units (78 %) and general surgical services (78 %), but little access to other consultants. About 40% of rural hospitals were more than 300 km from a Level-1 or Level-2 trauma centre. Of the 72 699 trauma cases, 4703 (6.5%) were treated in rural and 67 996 (93.5%) in urban hospitals. Rural versus urban case severity was similar: ISS rural: 8.6 (7.1), ISS urban: 7.2 (7.2). Trauma mortality was higher in rural than urban pre-hospital settings: 7.5% vs 2.6%. Reliable pre-hospital times were available for only a third of eligible cases. Rural mortality was significantly higher than urban mortality during ED stays (OR (95% IC): 2.14 (1.61-2.85)) but not after admission (OR (95% IC): 0.87 (0.74-1.02)). Conclusion: Rural hospitals treat equally severe trauma cases as do urban trauma centres but with fewer resources. The higher pre-hospital and in-ED mortality is of grave concern. Longer rural transport times may be a factor. Lack of reliable pre-hospital times precluded further analysis.
We investigated the effect of background noise on performance on the Montreal Cognitive Assessment (MoCA). Two groups of older adults (one with clinically normal hearing, one with hearing loss) and a younger adult group with clinically normal hearing were administered two versions of the MoCA under headphones in low and high levels of background noise. Intensity levels used to present the test were customized based on the hearing abilities of participants with hearing loss to yield a uniform level of difficulty across listeners in the high-level noise condition. Both older groups had poorer MoCA scores in noise than the younger group. Importantly, all participants had poorer MoCA scores in the high-noise (M = 22.7/30) compared to the low-noise condition (M = 25.7/30, p < .001). Results suggest that background noise in the test environment should be considered when cognitive tests are conducted and results interpreted, especially when testing older adults.
This study explored informal family caregiver experiences in supporting care transitions between hospital and home for medically complex older adults. Using a qualitative, grounded-theory approach, in-depth semi-structured interviews were conducted with community and resource case managers, as well as with informal caregivers of older hip-fracture and stroke patients, and of those recovering from hip replacement surgery. Six properties characterizing caregiver needs in successfully transitioning care between hospital and home were integrated into a theory addressing both a transitional care timeline and the emotional journey. The six properties were (1) assessment of unique family situation; (2) practical information, education, and training; (3) involvement in planning process; (4) agreement between formal and informal caregivers; (5) time to make arrangements in personal life; and (6) emotional readiness. This work will support research and clinical efforts to develop more well-informed and relevant interventions to most appropriately support patients and families during transitional care.
Water flow in plant tissues takes place in two different physical domains separated by
semipermeable membranes: cell insides and cell walls. The assembly of all cell insides and
cell walls are termed symplast and apoplast,
respectively. Water transport is pressure driven in both, where osmosis plays an essential
role in membrane crossing. In this paper, a microscopic model of water flow and transport
of an osmotically active solute in a plant tissue is considered. The model is posed on the
scale of a single cell and the tissue is assumed to be composed of periodically
distributed cells. The flow in the symplast can be regarded as a viscous Stokes flow,
while Darcy’s law applies in the porous apoplast. Transmission conditions at the interface
(semipermeable membrane) are obtained by balancing the mass fluxes through the interface
and by describing the protein mediated transport as a surface reaction. Applying
homogenization techniques, macroscopic equations for water and solute transport in a plant
tissue are derived. The macroscopic problem is given by a Darcy law with a force term
proportional to the difference in concentrations of the osmotically active solute in the
symplast and apoplast; i.e. the flow is also driven by the local concentration difference
and its direction can be different than the one prescribed by the pressure gradient.
Mathematical models of plant growth are generally characterized by a large number of
interacting processes, a large number of model parameters and costly experimental data
acquisition. Such complexities make model parameterization a difficult process. Moreover,
there is a large variety of models that coexist in the literature with generally an
absence of benchmarking between the different approaches and insufficient model
evaluation. In this context, this paper aims at enhancing good modelling practices in the
plant growth modelling community and at increasing model design efficiency. It gives an
overview of the different steps in modelling and specify them in the case of plant growth
models specifically regarding their above mentioned characteristics.
Different methods allowing to perform these steps are implemented in a dedicated platform
PYGMALION (Plant Growth Model Analysis, Identification and Optimization). Some of these
methods are original. The C++ platform proposes a framework in which stochastic or
deterministic discrete dynamic models can be implemented, and several efficient methods
for sensitivity analysis, uncertainty analysis, parameter estimation, model selection or
data assimilation can be used for model design, evaluation or application.
Finally, a new model, the LNAS model for sugar beet growth, is presented and serves to
illustrate how the different methods in PYGMALION can be used for its parameterization,
its evaluation and its application to yield prediction. The model is evaluated from real
data and is shown to have interesting predictive capacities when coupled with data
During the last two decades, molecular genetic studies and the completion of the
sequencing of the Arabidopsis thaliana genome have increased knowledge of
hormonal regulation in plants. These signal transduction pathways act in concert through
gene regulatory and signalling networks whose main components have begun to be elucidated.
Our understanding of the resulting cellular processes is hindered by the complex, and
sometimes counter-intuitive, dynamics of the networks, which may be interconnected through
feedback controls and cross-regulation. Mathematical modelling provides a valuable tool to
investigate such dynamics and to perform in silico experiments that may not be easily
carried out in a laboratory. In this article, we firstly review general methods for
modelling gene and signalling networks and their application in plants. We then describe
specific models of hormonal perception and cross-talk in plants. This mathematical
analysis of sub-cellular molecular mechanisms paves the way for more comprehensive
modelling studies of hormonal transport and signalling in a multi-scale setting.
Plants, algae, and fungi are essential for nearly all life on earth. Through
photosynthesis, plants and algae convert solar energy to chemical energy in the form of
organic compounds that sustains essentially all life on earth. In addition, plants and
algae convert the carbon dioxide produced by respiring organisms to oxygen that is needed
for respiration. Fungi decompose complex organic compounds produced by respiring organisms
so that molecules can be recycled in photosynthesis and respiration. Plants, algae, and
fungi have one important feature in common, their cells have walls. Expansive growth and
its regulation are central to the life and development of plant, algal, and fungal cells,
i.e. cells with walls. In recent decades there has been an explosion of information
relevant to expansive growth of cells with walls. Mathematical models have been
constructed in an attempt to organize and evaluate this information, to gain insight, to
evaluate hypotheses, and to assist in the selection and development of new experimental
studies. In this article some of the mathematical models constructed to study expansive
growth of cells with walls are reviewed. It is nearly impossible to review all relevant
research conducted in this area. Instead, the review focuses on the development of
mathematical equations that have been used to model expansive growth, morphogenesis, and
growth rate regulation of cells with walls. Also, relevant experimental findings are
reviewed, conceptual models are presented, and suggestions for future research are
proposed. The authors have attempted to provide an overview that is accessible to
researchers that are not working in this field.
Pollen tubes are tip growing plant cells that display oscillatory growth behavior. It has
been demonstrated experimentally that the reduction of the average pollen tube growth rate
through elevated extracellular calcium or borate concentrations coincides with a greater
amplitude of the growth rate oscillation and a lower oscillation frequency. We present a
simple numerical model of pollen tube growth that reproduces these results, as well as
analytical calculations that suggest an underlying mechanism. These data show that the
pollen tube oscillator is non-isochronous, and is different from harmonic oscillation.
Deformable cell model is developed to study pattern formation and to simulate plant
tissue growth. Each cell represents a polygon with a number of vertices connected by
springs. Some cells in the tissue can grow and divide, other cells are differentiated and
do not grow or divide but remain deformable. The model is used to investigate formation of
self-similar structures which reproduce the same cell organization during their growth. In
numerical experiments we observed that self-similar solutions can exist for a rather
precise choice of plant structure and mechanical properties of cell walls. We test the
model for simulation of apical meristems functioning which represent self-similar cell
structures in plants. At the next stage of modelling, auxin distribution is introduced by
means of diffusion and polar transport mechanisms. The existence of steady auxin
distribution in a growing root is investigated. Single as well as multiple auxin maxima
have been observed in model solutions.
Little is known about how persons with dementia and their care partners respond to mealtime changes that occur throughout the dementia journey. By interviewing 27 persons living with dementia and their 28 care partners, we explored the meaning and experience of change surrounding mealtimes. Participants adjusted to mealtime change by adapting to an evolving life, as a result of a dynamic process of becoming aware of change, attaching meaning to change, and responding to change. Seminal events compounded by a sense of things being different triggered awareness of mealtime changes. Meaning was attached to mealtime changes, observed through emotions experienced and diverse strategies developed to support mealtime values. Responding to change ranged from resisting, to being in a holding pattern, to transforming and adapting. Understanding how individuals and families adjust to mealtime changes, and the strategies they develop, provides critical insights for supporting families throughout the dementia journey.
Free energy lattice Boltzmann methods are well suited for the simulation of two phase flow problems. The model for the interface is based on well understood physical grounds. In most cases a numerical interface is used instead of the physical one because of lattice resolution limitations. In this paper we present a framework where we can both follow the droplet behavior in a coarse scale and solve the interface in a fine scale simultaneously. We apply the method for the simulation of a droplet using an interface to diameter size ratio of 1 to 280. In a second simulation, a small droplet coalesces with a 42 times larger droplet producing on it only a small capillary wave that propagates and dissipates.