Abstract Background The influence of menopausal status on depressive symptoms is unclear in diverse ethnic groups. This study examined the longitudinal relationship between changes in menopausal ...status and the risk of clinically relevant depressive symptoms and whether the relationship differed according to initial depressive symptom level. Methods 3302 African American, Chinese, Hispanic, Japanese, and White women, aged 42–52 years at entry into the Study of Women's Health Across the Nation (SWAN), a community-based, multisite longitudinal observational study, were evaluated annually from 1995 through 2002. Random effects multiple logistic regression analyses were used to determine the relationship between menopausal status and prevalence of low and high depressive symptom scores (CES-D < 16 or ≥ 16) over 5 years. Results At baseline, 23% of the sample had elevated CES-D scores. A woman was more likely to report CES-D ≥ 16 when she was early peri-, late peri-, postmenopausal or currently/formerly using hormone therapy (HT), relative to when she was premenopausal (OR range 1.30 to 1.71). Effects were somewhat stronger for women with low CES-D scores at baseline. Health and psychosocial factors increased the odds of having a high CES-D and in some cases, were more important than menopausal status. Limitations We used a measure of current depressive symptoms rather than a diagnosis of clinical depression. Thus, we can only make conclusions about symptoms current at annual assessments. Conclusion Most midlife women do not experience high depressive symptoms. Those that do are more likely to experience high depressive symptom levels when perimenopausal or postmenopausal than when premenopausal, independent of factors such as difficulty paying for basics, negative attitudes, poor perceived health, and stressful events.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Purpose
Sliding wear is a common phenomenon in the iron ore handling industry. Large-scale handling of iron ore bulk-solids causes a high amount of volume loss from the surfaces of ...bulk-solids-handling equipment. Predicting the sliding wear volume from equipment surfaces is beneficial for efficient maintenance of worn equipment. Recently, the discrete element method (DEM) simulations have been utilised to predict the wear by bulk-solids. However, the sensitivity of wear prediction subjected to DEM parameters has not been systemically investigated at single particle level. To ensure the wear predictions by DEM are accurate and stable, this study aims to conduct the sensitivity analysis at the single particle level.
Design/methodology/approach
In this research, pin-on-disc wear tests are modelled to predict the sliding wear by individual iron ore particles. The Hertz–Mindlin (no slip) contact model is implemented to simulate interactions between particle (pin) and geometry (disc). To quantify the wear from geometry surface, a sliding wear equation derived from Archard’s wear model is adopted in the DEM simulations. The accuracy of the pin-on-disc wear test simulation is assessed by comparing the predicted wear volume with that of the theoretical calculation. The stability is evaluated by repetitive tests of a reference case. At the steady-state wear, the sensitivity analysis is done by predicting sliding wear volumes using the parameter values determined by iron ore-handling conditions. This research is carried out using the software EDEM® 2.7.1.
Findings
Numerical errors occur when a particle passes a joint side of geometry meshes. However, this influence is negligible compared to total wear volume of a wear revolution. A reference case study demonstrates that accurate and stable results of sliding wear volume can be achieved. For the sliding wear at steady state, increasing particle density or radius causes more wear, whereas, by contrast, particle Poisson’s ratio, particle shear modulus, geometry mesh size, rotating speed, coefficient of restitution and time step have no impact on wear volume. As expected, increasing indentation force results in a proportional increase. For maintaining wear characteristic and reducing simulation time, the geometry mesh size is recommended. To further reduce simulation time, it is inappropriate using lower particle shear modulus. However, the maximum time step can be increased to 187% TR without compromising simulation accuracy.
Research limitations/implications
The applied coefficient of sliding wear is determined based on theoretical and experimental studies of a spherical head of iron ore particle. To predict realistic volume loss in the iron ore-handling industry, this coefficient should be experimentally determined by taking into account the non-spherical shapes of iron ore particles.
Practical implications
The effects of DEM parameters on sliding wear are revealed, enabling the selections of adequate values to predict sliding wear in the iron ore-handling industry.
Originality/value
The accuracy and stability to predict sliding wear by using EDEM® 2.7.1 are verified. Besides, this research accelerates the calibration of sliding wear prediction by DEM.
•Optimization of biomass port terminal equipment is presented.•MILP model minimizes investment and operational costs in biomass bulk terminals.•Real data from industry used as input.•Results provide ...optimal equipment allocation and utilization, optimal terminal size and associated logistics.•Insight on importance of storage and utilization costs when dealing with biomass.
This paper investigates the optimization of biomass terminal equipment deployment. A mixed integer linear programming model is developed and applied to minimize the terminal’s investment and operational costs related to dedicated and partially used or shared equipment between a terminal’s operational steps. The results minimize annual terminal costs through equipment and infrastructure selection and utilization. Tipping points where the technology and equipment type or size change in relation to the increasing throughput are highlighted. Analytical results emphasize the importance of storage costs in all biomass terminals, as well as the critical influence of operational costs in larger facilities.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
To improve the understanding of the mixing performance of double shaft, batch-type paddle mixers, the discrete element method (DEM) in combination with a Plackett–Burman design of experiments ...simulation plan is used to identify factor significance on the system’s mixing performance. Effects of several factors, including three material properties (particle size, particle density and composition), three operational conditions (initial filling pattern, fill level and impeller rotational speed) and three geometric parameters (paddle size, paddle angle and paddle number), were quantitatively investigated using the relative standard deviation (RSD). Four key performance indicators (KPIs), namely the mixing quality, mixing time, average mixing power and energy required to reach a steady state, were defined to evaluate the performance of the double paddle mixer. The results show that the material property effects are not as significant as those of the operational conditions and geometric parameters. In particular, the geometric parameters were observed to significantly influence the energy consumption, while not affecting the mixing quality and mixing time, showing their potential towards designing more sustainable mixers. Furthermore, the analysis of granular temperature revealed that the centre area between the two paddles has a high diffusivity, which can be correlated to the mixing time.
Large-scale handling of particulate solids can cause severe wear on bulk solids handling equipment surfaces. Wear reduces equipment life span and increases maintenance cost. Examples of traditional ...methods to reduce wear of bulk solids handling equipment include optimizing transport operations and utilizing resistant materials. To our knowledge, the so-called bionic design has not been utilized. Bionic design is the application of biological models, systems, or elements to modern engineering. Bionic design has promoted significant progress on the development of engineering products and systems. In order to use bionic design for wear reduction of bulk solids handling equipment surfaces, this paper introduces bionic design to bulk solids handling on the basis of analogies between biology and bulk solids handling. In addition, a bionic design methodology for the wear reduction of bulk solids handling equipment surfaces is formulated. Based on the bionic design methodology, two bionic models used for abrasive and erosive wear reduction of bulk solids handling equipment surfaces are proposed.
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BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
An ideal unit of bulk transport or storage equipment is able to handle cohesive iron ore with consistent productivity. In practice, however, uncontrollable bulk property variations affect the ...productivity. Therefore, it is important to understand the effect of uncontrollable variations on the process. This study quantifies variability and interdependency of bulk property of a range of cohesive iron ore products. Three different laboratory tests relevant to storage and excavation processes are used. Using a multi-variate experimental plan, three influencing characteristics of iron ore – type, moisture content and consolidation state – are included. A stress-history dependent behavior is captured in both the shear and penetration tests, with the results being highly dependent on the pre-consolidation stress. The outcome of this study enables future research on minimizing the effect of uncontrollable bulk properties variability of iron ore and other cohesive materials in the design procedure of transport and storage processes.
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•This study quantifies bulk property variability and interdependency of a range of cohesive iron ore products.•Bulk properties of cohesive iron ores are highly dependent to magnitude of pre-consolidation stress.•The flowability (ffc) of samples is categorized as very cohesive to cohesive.•A weak correlation between level of moisture content and ffc is found.•Ledge angle of repose test results are in the range of 55° to 90°.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Psychosocial and health-related risk factors for depressive symptoms are known. It is unclear if these are associated with depressive symptom patterns over time. We identified trajectories of ...depressive symptoms and their risk factors among midlife women followed over 15 years.
Participants were 3300 multiracial/ethnic women enrolled in a multisite longitudinal menopause and aging study, Study of Women's Health Across the Nation. Biological, psychosocial, and depressive symptom data were collected approximately annually. Group-based trajectory modeling identified women with similar longitudinal patterns of depressive symptoms. Trajectory groups were compared on time-invariant and varying characteristics using multivariable multinomial analyses and pairwise comparisons.
Five symptom trajectories were compared (50% very low; 29% low; 5% increasing; 11% decreasing; 5% high). Relative to whites, blacks were less likely to be in the increasing trajectory and more likely to be in the decreasing symptom trajectory and Hispanics were more likely to have a high symptom trajectory than an increasing trajectory. Psychosocial/health factors varied between groups. A rise in sleep problems was associated with higher odds of having an increasing trajectory and a rise in social support was associated with lower odds. Women with low role functioning for 50% or more visits had three times the odds of being in the increasing symptom group.
Changes in psychosocial and health characteristics were related to changing depressive symptom trajectories. Health care providers need to evaluate women's sleep quality, social support, life events, and role functioning repeatedly during midlife to monitor changes in these and depressive symptoms.
Background:
Shared decision-making in cardiology is increasingly recommended to improve patient-centeredness of care. Decision aids can improve patient knowledge and decisional quality but are ...infrequently used in real-world practice. This mixed-methods study tests the efficacy and acceptability of a decision aid integrated into the electronic health record (Integrated Decision Aid IDeA) and delivered by clinicians for patients with atrial fibrillation considering options to reduce stroke risk. We aimed to determine whether the IDeA improves patient knowledge, reduces decisional conflict, and is seen as acceptable by clinicians and patients.
Methods:
A small cluster randomized trial included 6 cardiovascular clinicians and 66 patients randomized either to the IDeA (HealthDecision) or usual care (clinician discretion) during a clinical encounter when stroke prevention treatment options were discussed. The primary outcome was patient knowledge of personalized stroke risk. Exploratory outcomes included decisional conflict, values concordance, trust, the presence of a shared decision-making process, and patient knowledge related to time spent using the IDeA. Additionally, we conducted semistructured interviews with clinicians and patients who used the IDeA were conducted to assess acceptability and predictions of future use.
Results:
The IDeA significantly increased patients’ knowledge of their stroke risk (odds ratio, 3.88 95% CI, 1.39–10.78;
P
<0.01). Patients had less uncertainty about their final decision (
P
=0.04). There were no significant differences in values concordance, trust in clinician or shared decision-making. Despite training, each clinician used the IDeA differently. Qualitative analysis revealed patients prefer using the IDeA earlier in their diagnosis. Clinicians were satisfied with the IDeA, yet varied in the contexts in which they planned to use it in the future.
Conclusions:
Using an Integrated Decision Aid, or IDeA, increases patient knowledge and lessens uncertainty for decision-making around stroke prevention in atrial fibrillation. Qualitative data provide insight into potential implementation strategies in real-world practice.
Self-reported data suggest American adults with multiple chronic conditions account for 25.7% to 60% of the population. Despite emphasis on information technology to improve quality in health care, ...data addressing outcomes of clinically focused, provider-oriented dashboards are limited. To explore integrating performance platforms into clinical care, the authors designed a platform-based intervention to address 2 prevalent chronic conditions with significant long-term burden. This study used a performance platform to enhance clinicians' management of patients with diabetes and osteoporosis. Descriptive statistics were used to summarize patients' surveys and quality metrics, and to analyze clinicians' knowledge, attitudes, and beliefs in the pre and post time frames. The frequency of screening for osteoporosis in women improved post intervention (40% vs. 44%,
P
< 0.0001), whereas other quality metrics did not. Clinician respondents were primarily physicians (82%), white (73%), internal medicine specialists (58%), with an average of 18 years' experience, and nearly equally male and female. Their percent of correctly answered knowledge questions increased slightly in the postintervention phase for osteoporosis and hypoglycemia (0.53 and 1.74, respectively); however, results were not statistically significant (
P
> 0.4). Post intervention, clinicians reported that their attitudes and beliefs regarding disease management had changed in the past 6 months in a positive direction. Although few outcomes studied changed over time, results suggest that performance platforms may have a role to play in managing chronic conditions. However, their efficacy must continue to be evaluated in order to improve understanding of optimal approaches to integrating technology into patient care.
OBJECTIVE—We investigated associations between segment-specific carotid intima-medial thickness (IMT) and cardiovascular risk factors collected before menopause for insight into mechanisms of ...atherosclerosis development.
METHODS AND RESULTS—Participants were 453 healthy women (aged 46 to 58 years) enrolled in a dietary and physical activity randomized clinical trial. Ultrasound scan measures were taken ≈2.7 years after baseline in the common carotid artery (CCA), bifurcation (bulb), and internal carotid artery (ICA) segments. When scanned, 84% remained premenopausal. In linear regression models adjusted for age, menopausal status, and intervention group, measures independently (P<0.05) and positively associated were as followsbaseline weight (β=0.007 per 5 kg), systolic blood pressure (SBP; β=0.008 per 10 mm Hg), and age (β=0.02 per 5 years) with CCA IMT; smoking (β=0.08), weight (β=0.009), and SBP (β=0.02) with bulb IMT; and apoprotein B (β=0.01 per 0.1 g/L) with ICA IMT. Differential effects in a repeated measures model with all 3 IMT locations showed these risk factors to have segment-specific positive associations. The effect of weight was strongest in the CCA, smoking and SBP were specific to the bulb, and apoprotein B was strongest in the ICA segment.
CONCLUSION—Analyses indicate that cardiovascular risk factors may differentially affect IMT in the CCA, bulb, and ICA segments of healthy middle-aged women.
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