Effects Of Different Models Research Articles

PP404 Effect Evaluation Of Two Family Doctor Contracting Service Models On Diabetic Patients: A Real-World Study In Chengdu, China

IntroductionTo strengthen the care capacity of primary facilities, China has vigorously promoted the construction of a hierarchical medical system and a family doctor care system. In July 2017, a family doctor care plan was launched in an urban district of Chengdu, Sichuan Province, and two family doctor contracting service models were adopted, one provided a basic-service package and the other a paid-service package. In order to evaluate the effect of different models on diabetic patients, this study conducted a real world study based on the district healthcare database.MethodsDiabetic patients who contracted family doctor services January 2018 to January 2019 as reported in the database were enrolled in the paid- or basic-service group. Propensity score matching (PSM) was conducted to balance the distribution of covariances between the groups. The results of the first and last examination of glycosylated hemoglobin, low-density lipoprotein cholesterol (LDL-C), systolic and diastolic blood pressure in the groups were compared by independent sample t-test and chi-square test.ResultsIncluded were 4,871 patients in basic-service and 394 patients in paid-service. In both groups the total control rates of blood pressure, glycosylated hemoglobin and LDL-C at the last physical examination were 43.67, 79.28 and 51.11 percent, respectively, a significant increase from pre-test. The combined control rates of HbAlc, LDL-C and blood pressure in the basic- and paid-service group were 20.76% and 22.37%, respectively. After PSM, there was no significant difference between the groups.ConclusionsUp to now, there is no significant difference between basic-service and paid-service family doctor contracting service models in improving the comprehensive control rate of diabetic patients. The possible reasons may be that the quality and content of paid-service is not as good as expected, the period of implementation is not long enough and the sample size of paid-service patients is limited.

A four-step method to centralize pancreatic surgery, accounting for volume, performance and access to care

BackgroundAdequate criteria for pancreatic surgery centralization are debated. This retrospective study aimed to define a reproducible method for complex care centralization, accounting for hospital performance and access to care. MethodsThe method consisted in: 1. Analysis of overall outcome and mortality-related factors. 2. Assessment of volume and adjusted mortality of each hospital. 3. Definition of different centralization models. 4. Final adjustments to guarantee access to care, evaluating travel times and waiting lists. This method was tested on Lombardy, the most populous Italian region (about 10 million inhabitants, 24 000 km2). ResultsAccording to Ministry of Health data, 79 hospitals performed 3037 resections in 2014–2016. Mean overall mortality was 5.0%, increasing from 2.3%, of seven high-volume facilities (>30 resections/year) to 10.7% of 56 low-volume facilities (<10 resections/year). Five centralization models were tested (range: 7–23 hospitals): the best performing model included seven high-volume facilities, providing both low mortality (<2%), and easy access to care, namely reasonable travel time (≤60 min for >90% of the population), and limited impact on waiting list (1.1 extra-resection/hospital/week). ConclusionThe four-step method appears as a flexible tool to centralize pancreatic surgery, allowing regulatory institutions to estimate the effect of different models.

Absence of the Shb gene in mixed-lineage leukemia MLL-AF9 cells increases latency in mice despite higher proliferation rates in vitro

Mixed lineage leukemia (MLL) arises from several KMT2A-gene chromosomal translocations. Shb gene deficiency has been found to exhibit pleiotropic effects in different models of leukemia, and consequently, this study aimed to investigate MLL-AF9-induced leukemia in Shb deficiency. Bone marrow cells from wild type and Shb knockout (KO) mice were transduced with the MLL-AF9 gene. Shb KO MLL-AF9 cells proliferated at an increased rate, exhibited altered expression of certain cytokine genes (Kitl, Csf3, IL6, IL1b) and higher expression of cell cycle genes (Ccnd2, Ccne1). Mice receiving Shb KO MLL-AF9 cells showed longer latency without displaying any difference in rates of leukemic cell proliferation, indicating a dichotomy between the in vitro and in vivo phenotypes. The mice with Shb deficient MLL-AF9 cells had a lower content of leukemic bone marrow cells allowing elevated normal hematopoiesis, explaining the longer latency. Finally, Shb knockout GFP-positive bone marrow cells showed a higher percentage of cells expressing myeloid markers. The result suggests a role of Shb in the progression of leukemia and that the relevance of the Shb gene is context-dependent as inferred from the differences between the in vivo and in vitro responses. These findings help to obtain an increased understanding of human MLL-AF9 leukemia.

Impact of advanced nursing practice through nurse-led clinics in the care of cancer patients: A scoping review.

This scoping review aims at exploring the effectiveness of nurse-led advanced practice for patients with cancer. This review followed the PRISMA extension for scoping reviews. Randomised controlled trials on cancer nurse-led clinics for patient outcomes, costs, service utilisation and other outcomes were included. Databases such as MEDLINE, CENTRAL, CINAHL, EMBASE and PsychINFO were searched based on MeSH terms. Thematic analysis was used to synthesise results of the included studies. Seventeen articles were included, published between 2001 and 2019. There were methodological shortcomings with a number of the studies reviewed. Five themes were identified including (1) rationale for developing nurse-led clinics, (2) mode of delivery of nurse-led clinics, (3) the content of nurse-led clinics, (4) exploring patient outcomes and (5) satisfaction with nurse-led clinics. The results support the effectiveness of nurse-led clinics in improving self-reported responses such as distress levels, satisfaction, quality of life, depressive symptoms, concerns and vomiting among cancer patients. Following a sound protocol for both the study and the reporting is recommended, and future studies should focus more on costs and effectiveness of different models of care administered by advanced practice nurses. Effectiveness of nurse-led clinics needs further evaluation with stronger trials and wider focus on nursing-sensitive clinical outcomes and costs.

Involvement of informal carers in discharge planning and transition between hospital and community mental health care: A systematic review.

Family members and friends (informal carers) are very important for providing support to people with mental health difficulties. When these carers are included to care planning patients seem to benefit, as they are less likely to relapse. There are three types of interventions including carers in the patients'transition 1) programmes that offer education in hospital; 2) programmes that involve carers in planning the patients discharge; and 3) programmes that involve carers in hospital care, discharge planning and also follow-up in the community. Interventions including carers that take place both in the hospital and the community have the clearest evidence for benefit on relapse reduction. Comprehensive interventions have the best evidence for effectiveness but challenges in their implementation and resourcing should be considered. It might worth trying to identify and test simpler interventions focusing on discharge planning that can be used in busy services and require more limited resources whilst providing opportunities for the participation of carers. INTRODUCTION: Involving informal carers (family and friends of patients) in mental health interventions can lead to positive clinical and psychosocial outcomes such as relapse prevention or treatment adherence. To explore the evidence on the effectiveness of different models that involve carers in the transition between hospital and community mental health care. Five electronic databases (PsycINFO, CINAHL, MEDLINE, Embase and Scopus) and Grey literature (Open Grey and Grey Literature report) were systematically searched. The results were analysed using a narrative synthesis. Fourteen papers were identified. They described twelve interventions that were categorized into three groups: 1) purely educational programmes in preparation of discharge; 2) programmes that involved carers in planning the transition from the mental health inpatient treatment to community mental health services; and 3) programmes that bridged into the aftercare involving carers in community follow-up. The most comprehensive interventions, i.e. those including psychoeducation, care planning and aftercare follow-up were better evaluated and showed a clearer benefit in improving long-term outcomes and, in particular, reduce re-hospitalization. Comprehensive interventions showed the clearest benefit in improving long-term clinical outcomes of patients. Future research should explore implementation, costs and cost-effectiveness, as comprehensive interventions delivered across different settings are likely to require wide-ranging organizational changes and significant resources.

Silymarin protects against sepsis-induced acute liver and kidney injury via anti-inflammatory and antioxidant mechanisms in the rat

Sepsis is a leading cause of death among intensive care patients. During sepsis, exaggerated reaction to infection leads to massive production of reactive oxygen species and inflammatory mediators, which eventually leads to multiple organ damage. Silymarin is a well-known antioxidant and cytoprotective agent, which showed protective effects in different models of disease. Thus, we hypothesized that silymarin would be protective against sepsis-induced liver and kidney injury. Sepsis was induced in rats by the cecal ligation and puncture (CLP) method. Rats were divided into sham, CLP-non-treated and CLP treated with silymarin (100 mg/kg, i.p. 1 h following CLP). After 24 h, rats were euthanized for blood and tissue samples, which were used for assessment of MDA, NO, GSH, IL-6 and TNF-α levels and SOD activity, in addition to renal and hepatic function parameters. Survival study was conducted using another set of animals following the same previously mentioned procedure. Silymarin showed protective effects evidenced by enhanced overall survival following sepsis (80% in silymarin-treated vs. 20% in septic group), in addition to improvement of hepatic and renal function parameters and reduction of MDA, NO, IL-6 and TNF-α levels. Moreover, silymarin supported the endogenous antioxidant mechanisms via elevation of GSH levels and reinforcement of SOD activity. In conclusion, silymarin protects against sepsis-induced hepatic and renal injury, possibly via antioxidant and anti-inflammatory mechanisms.

Influence of stacking sequence on the mechanical properties of 3D E-glass/bamboo non-woven hybrid epoxy composites

Hybridization of composites is one of the many ways to optimize cost, manufacturing process and strength required for a particular application. This demands a need for knowledge about the best possible ways to deal with the dissimilar materials in the composite system. Very little light has been shed about the stacking sequence implemented while dealing with non-woven natural fiber mats and 3D woven glass fiber fabric as reinforcement and effects of different models on the strength of composite – which has been dealt very vividly in this research work. Two types of hybrid stacking sequence were implemented using non-woven bamboo fiber mat and 3D E-glass fiber fabric, namely H1, which has two bamboo mats at the centre with a glass fabric on either side as extreme layers, and H2, which has 3 glass fabric and 2 bamboo mat placed stacked alternatively with glass fabric being as extreme layers on either side again. For comparative purposes, 4 layers each of E-glass fabric and bamboo mat composites were also made. Tensile, flexural and ILSS tests were conducted on all four of these samples and results showed that lying between the consistent superior strength displayed by pure glass composite and inferior strength of pure bamboo composite, the H1 sample stacking sequence performed better than the H2 sample. The major reason for the failure of the hybrid composites was observed to be due to delamination at dissimilar laminae boundary which were more in H2 samples than H1 composite. Scanning Electron Microscopy was employed to understand the modes of failure.

Making Sense of Scientific Simulation Ensembles With Semantic Interaction

AbstractIn the study of complex physical systems, scientists use simulations to study the effects of different models and parameters. Seeking to understand the influence and relationships among multiple dimensions, they typically run many simulations and vary the initial conditions in what are known as ‘ensembles’. Ensembles are then a number of runs that are each multi‐dimensional and multi‐variate. In order to understand the connections between simulation parameters and patterns in the output data, we have been developing an approach to the visual analysis of scientific data that merges human expertise and intuition with machine learning and statistics. Our approach is manifested in a new visualization tool, GLEE (Graphically‐Linked Ensemble Explorer), that allows scientists to explore, search, filter and make sense of their ensembles. GLEE uses visualization and semantic interaction (SI) techniques to enable scientists to find similarities and differences between runs, find correlation(s) between different parameters and explore relations and correlations across and between different runs and parameters. Our approach supports scientists in selecting interesting subsets of runs in order to investigate and summarize the factors and statistics that show variations and consistencies across different runs. In this paper, we evaluate our tool with experts to understand its strengths and weaknesses for optimization and inverse problems.

Stochastic recurrent wavelet neural network with EEMD method on energy price prediction

Novel hybrid neural network prediction model (denoted by E-SRWNN) is formed by combining ensemble empirical mode decomposition (EEMD) and stochastic recurrent wavelet neural network (SRWNN), in order to improve the precision of energy indexes price forecasting. Energy index price series are non-stationary, nonlinear and random. EEMD method is utilized to decompose the closing prices of four energy indexes into subsequences with different frequencies, and the SRWNN model is composed by adding stochastic time effective function and recurrent layer to the wavelet neural network (WNN). Stochastic time effective function makes the model assign different weights to the historical data at different times, and the introduction of recurrent layer structure will enhance the data learning. In this paper, E-SRWNN model is compared with other WNN-based models and the deep learning network GRU. In the error evaluation, the general standards, such as linear regression analysis, mean absolute error and theil inequality coefficient, are utilized to compare the predicted effects of different models, and then multiscale complexity-invariant distance is applied for further analysis. Empirical research illustrates that the proposed E-SRWNN model displays strong forecasting ability and accurate forecasting results in energy price series forecasting.

Physician-to-Nurse Handover: A Systematic Review on the Effectiveness of Different Models.

Effective professional communication and accurate transfer of relevant clinical information are crucial components of healthcare delivery. National and international health authorities strongly recommend the adoption of effective handover practice. Still, scant evidence is available on the impact of different multiprofessional handover models. We carried out a systematic review following the Prepared Items for Systematic Reviews and Meta-Analysis guidelines to retrieve, pool, and critically appraise the available evidence on the effectiveness of different physician-to-nurse handover models adopted in inpatient settings. We identified 1.243 citations searching the databases Medline, Embase, and CINAHL. After screening, 10 studies were included in the review reporting results on the effectiveness of 8 different handover models, measured on 44 different outcomes, grouped into: (1) process of care and efficiency outcomes, (2) patients' outcomes, and (3) healthcare professionals-related outcomes. Overall, applying structured handover tools improve healthcare practice and selected outcomes; however, not only solid evidence on the effectiveness of different handover models is scant but also global consensus is lacking on which standardized measures and indicators to use to assess their impact. In times of healthcare delivery models of growing complexity, multiprofessional handover is a key component of care paths. Although there is overall consensus on the need for improving the quality and safety of multiprofessional handover, the evidence on the tools available to achieve it and the metrics to measure their impact is heterogeneous. We urge that rigorous studies are conducted to inform the planning, implementation, and monitoring of effective handover, with the ultimate aim of improving quality of care and patient safety.

Effect of Aerobic and Resistance Training on Endothelial Progenitor Cells in Mice with Type 2 Diabetes.

Since no study has explored whether exercise could improve impaired proliferation, migration, and angiogenesis of endothelial progenitor cells (EPCs) in animal models or humans with type 2 diabetes, we aimed to explore the effect of different models of exercise on EPC function and expression of caveolin-1, PI3K, and AKT in mice with type 2 diabetes. Male db/db mice (age: 8 weeks) with type 2 diabetes were subjected to aerobic training (AT), resistance training (RT), or combined aerobic and resistance training (AT+RT) 3 or 4 days/week. Mice in the control group remained sedentary with no specific training requirement. Bone marrow-derived EPCs were isolated, and the protein concentrations of caveolin-1, Pi3k, and AKT, and EPC function, were identified in the 1st, 4th, 8th, and 12th weeks of the intervention. Greater increases in proliferation, migration, and angiogenesis were observed in the AT, RT, and AT+RT groups than in the control group. AT+RT was more effective than AT or RT in improving the migratory and angiogenesis function of EPCs in mice with type 2 diabetes and achieved maximum improvement after 8 weeks of intervention. Western blot analysis showed that caveolin-1, p-PI3k, and p-Akt levels were obviously increased in the AT, RT, and AT+RT groups compared with the control group. The expression level of these proteins in the AT+RT group was higher than that in the AT and RT groups. AT+RT may be a helpful reference when choosing exercise methods for the prevention of diabetes-related cardiovascular diseases.

Effect of Levosimendan, an Inodilator, on Streptozotocin‐Induced Diabetic Nephropathy in Rats

Levosimendan, an inodilator, was shown to have a renal protective effect in different models of kidney dysfunction in experimental animals and in patients with heart failure. The aim of this study was to examine the effect of levosimendan on streptozotocin‐induced early diabetic nephropathy. Male Sprague Dawley rats (n = 24, 320–400 g) were randomly distributed into four groups and treated for 6 weeks. Groups 1 and 3 received either vehicle or levosimendan (1 mg/kg/day) for the last three weeks, respectively. Groups 2 and 4 were rendered diabetic by a single i.p. injection of streptozotocin (60 mg/kg) and were treated as in groups 1 and 3, respectively. At the end of the experiment, rats were placed in metabolic cages and urine was collected for biochemical analysis. Rats were then anesthetized and blood samples collected for biochemical analysis. Kidneys were removed for histopathology. In the untreated diabetic group, there was a significant decrease in body weight, polyuria and increased relative kidney weight. There was increased urinary albumin/creatinine ratio (UACR), 24 hour (h) albumin level and N‐acetyl‐β‐D‐glucosaminidase (NAG)/creatinine ratio (UNCR). Streptozotocin did not cause a significant effect on creatinine clearance when adjusted to body weight. In addition, diabetes was associated with increased oxidative stress [reduced plasma total antioxidant capacity (TAC) and catalase activities]. Kidneys from streptozotocin‐treated rats showed focal clear renal tubular cells affecting proximal convoluted tubules and focal mild interstitial fibrosis at the cortico‐medullary junction. Levosimendan significantly attenuated the reduction in body weight, polyuria and the increase in relative kidney weight. In addition, it significantly attenuated the increase in UACR, urinary 24 h albumin level and UNCR in diabetic rats. It also significantly mitigated the decrease in plasma TAC and catalase activities in diabetic rats. Rats in the diabetic group treated with levosimendan showed less clear cell changes but similar interstitial fibrosis when compared with the untreated diabetic group. This study shows that levosimendan ameliorated some of the changes seen in streptozotocin‐induced early diabetic nephropathy in rats. This could be partly due to its antioxidative effects.Support or Funding InformationSupported by an internal grant from Sultan Qaboos University (IG/MED/PHAR/18/01)

Physical Activity as an Asset of Quality of Life / Fizička aktivnost u funkciji kvaliteta života

Quality of life as one of the significant dimensions of life can be viewed and promoted in various ways. From the corpus of the multidisciplinary approach, in our work we have opted for physical activity as an important basis for the quality of life. Specifically, this paper aims to determine the effect of different physical activity programs - experimental models (E-fitball exercises during work breaks, E1 - aqua aerobics, and E2 - Nordic walking, applied over a period of three months - three times a week) on the transformation of the morphological status of physically inactive women in order to improve the quality of life. The research problem is related to the effects of different models of physical activity programs in modifying the morphological - body structure and improving the quality of life. We have defined the general hypothesis as follows: The implementation of physical activity programs (fitball, aqua aerobics, Nordic walking) will lead to positive transformational changes in morphological - body status, thus improving the quality of life. The sample consisted of 84 subjects, women aged 30 to 40, leading a sedentary lifestyle. We tested the variables that characterize the morphological and physical status of the subjects. In order to accomplish the tasks of research and achieve its goal, a complex methodology was applied, which consisted of the following methods: experimental method with three experimental groups, morphological anthropometry method, bioelectric impedance method, descriptive statistics method (measures of central tendency and measures of dispersion), testing differences of arithmetic means (Student's t-criterion), one-factor variance analysis (ANOVA1), theoretical analysis - content analysis method. A comparative experiment with different models of physical activity programs showed a significant statistical difference for all tested morphological indicators (with the exception of the body height variable). The dynamics of the t-test results in the variables for the assessment of morphological status showed a significant statistical difference (significance level p 0.05) between the initial and final treatment in all experimental groups. In the final testing, we register the difference between the groups with the arm circumference variable (in favor of experimental group E1 (aqua aerobics) and E2 (Nordic walking), the thickness of the triceps skin fold (in favor of E1 and E2) and the thickness of the supriliac skin fold (in favor of E1 and E2) By looking at the results of the percentage of body fat (FAT%) after the application of the experimental program, we register the highest fat reduction in the experimental group E1 (aqua aerobics). Applied physical activity models are a good instrument for maintaining and optimizing the morphological status of physically inactive women and improving the quality of life for women.

Addressing the efficiency of X-ray protective eyewear: Proposal for the introduction of a new comprehensive parameter, the Eye Protection Effectiveness (EPE)

Radioprotection of the eye lens of medical staff involved in Surgical procedures is a subject of international debates since ICRP recommended, on 2011, a lower equivalent dose limit for the lens of the eye. In this work we address the effectiveness of different models of X-ray protective eyewear by relating actual dosimetry measurements to an ad hoc developed mathematical model, in order to disentangle the contribution of geometrical factors and shield capabilities. Phantom irradiation was carried out in fixed exposure conditions in angiographic room: we found that measured Dose Reduction Factors (DRF) strongly depend on the ergonomics of the investigated eyewear. Actually a very poor DRF was observed in the case of a glass model in spite of its high nominal attenuation, whereas a protective tool with low shielding capabilities such a visor resulted much more effective as a consequence of is shape (i.e. extended geometric protection of the eye lens). Our work highlights the need of the introduction of a specific parameter to quantify the effectiveness of the protection tools and able to predict their DRF by taking into account the geometry of the clinical condition of exposure. Aiming at making steps forward the standardization of the guidelines concerning the features of eye protective tools, we developed a simple mathematical model describing the eye lens irradiation geometry which allows the introduction, for each eyewear, of a comprehensive parameter, the Eye Protection Effectiveness (EPE), that, for any defined clinical irradiation condition and glass shielding capabilities and shape, defines the overall effective X-ray protection of the eyewear.

Biased Learning under Model Uncertainty

This paper proposes a model of how biased individuals update beliefs in the presence of informational ambiguity. Individuals are ambiguous about the actual signal-generating process and interpret signals according to the model that can best support their biases. This paper provides a complete characterization of the limit beliefs under this rule. The presence of model ambiguity has the following effects. First, it destroys correct learning even if infinitely many informative signals can be observed. When the ambiguity is sufficiently high, individuals can justify their biases, leading to belief extremism and polarization. Second, an ambiguous individual can exhibit greater confidence than a Bayesian individual with any feasible model perception. This phenomenon comes from a novel complementary effect of different models in the belief set.

Time series forecasting of solar power generation for large-scale photovoltaic plants

Accurate solar power forecasting is essential for grid-connected photovoltaic (PV) systems especially in case of fluctuating environmental conditions. The prediction of PV power output is critical to secure grid operation, scheduling and grid energy management. One of the key elements in PV output prediction is time series analysis especially in locations where the historical solar radiation measurements or other weather parameters have not been recorded. In this work, several time series prediction methods including the statistical methods and those based on artificial intelligence are introduced and compared rigorously for PV power output prediction. Moreover, the effect of prediction time horizon variation for all the algorithms is investigated. Hourly solar power forecasting is carried out to verify the effectiveness of different models. The data utilized in the current work comprises 3640 h of operation data taken from a 20 MW grid-connected PV station in China.

Food Rescue Intervention Evaluations: A Systematic Review

Food rescue, the practice of gathering food that could otherwise be wasted and redirecting it for human consumption, represents a critical opportunity to improve food security and reduce waste. As global interest in reducing hunger and food waste grows, better insight is needed to assess and compare the effectiveness of different models of food rescue. We conducted a systematic review of peer-reviewed studies evaluating food rescue interventions with the aim of synthesizing findings and comparing methodologies. We searched PubMed, Academic Search Ultimate, and Science Citation Index for studies published worldwide, in English, through June 2019. Studies were included that: a) evaluated an existing or proposed food rescue intervention and, b) quantitatively or qualitatively measured the intervention impact. All nineteen included studies were observational and the intervention types ranged widely. The most commonly reported metric was the weight of food recovered. Few studies reported client outcome measures. The included studies suggested promising effects of food rescue interventions, including positive return on investment, decreased environmental burden, large quantities of food rescued and clients served, and high stakeholder satisfaction. Comparison across studies was challenging, however, due to inconsistent metrics and insufficiently detailed methodology. This review documents a need for additional evaluation of food rescue interventions and recommends a standardized methodology. Additional dialogue among key stakeholders is warranted to develop consistent, meaningful metrics to assess food rescue.

Standardizing the categorizations of models of aftercare for survivors of childhood cancer

BackgroundWith significant improvements in the survival rates for most childhood cancers, there is increased pressure to determine how follow-up or aftercare for survivors is best structured.Main bodyPrevious work in this area has not been consistent in how it categorizes models of aftercare, which risks confusion between studies and evaluations of different models. The adoption of a standardized method for classifying and describing different models of aftercare is necessary in order to maximize the applicability of the available evidence. We identify some of the different ways models of aftercare have been classified in previous research. We then propose a revised taxonomy which allows for a more consistent classification and description of these models. The proposed model bases the classification of models of aftercare on who is the lead provider, and then collects data on five other key features: which other providers are involved in providing aftercare, where care is provided, how are survivors engaged, which services are provided, and who receives aftercare.ConclusionThere is a good deal of interest in the effectiveness of different models of aftercare. Future research in this area would be assisted by the adoption of a shared taxonomy that will allow programs to be identified by their structural type.

Variations of Drought Tendency, Frequency, and Characteristics and Their Responses to Climate Change under CMIP5 RCP Scenarios in Huai River Basin, China

Huai River Basin (HRB) is an important food and industrial production area and a frequently drought-affected basin in eastern China. It is necessary to consider the future drought development for reducing the impact of drought disasters. Three global circulation models (GCMs) from Coupled Model Intercomparison Project phase 5 (CMIP5), such as CNRM-CM5 (CNR), HadGEM2-ES (Had) and MIROC5 (MIR), were used to assessment the future drought conditions under two Representative Concentration Pathways (RCPs) scenarios, namely, RCP4.5 and RCP8.5. The standardized precipitation evapotranspiration index (SPEI), statistical method, Mann-Kendall test, and run theory were carried out to study the variations of drought tendency, frequency, and characteristics and their responses to climate change. The research showed that the three CMIP5 models differ in describing the future seasonal and annual variations of precipitation and temperature in the basin and thus lead to the differences in describing drought trends, frequency, and drought characteristics, such as drought severity, drought duration, and drought intensity. However, the drought trend, frequency, and characteristics in the future are more serious than the history. The drought frequency and characteristics tend to be strengthened under the scenario of high concentration of RCP8.5, and the drought trend is larger than that of low concentration of RCP4.5. The lower precipitation and the higher temperature are the main factors affecting the occurrence of drought. All three CMIP5 models show that precipitation would increase in the future, but it could not offset the evapotranspiration loss caused by significant temperature rise. The serious risk of drought in the future is still higher. Considering the uncertainty of climate models for simulation and prediction, attention should be paid to distinguish the effects of different models in the future drought assessment.

Bubbling/slugging flow behavior in a cylindrical fluidized bed: ECT measurements and two-fluid simulations

While the Eulerian two-fluid models (TFM) are now reasonably well established to predict the “time-averaged” flow behavior of gas–solid flow in fluidized beds, quantitative predictions of inherently unsteady local solid-phase distribution and bubbling/slugging behavior using the TFM continues to be a challenge. In the present work, we have investigated time-evolution of solid volume fraction (αs) distribution and bubbling/slugging behavior in a laboratory-scale fluidized bed using the Electrical Capacitance Tomography (ECT) measurements and TFM simulations. The ECT was used to measure temporally- and spatially-resolved local αs distribution and these measurements were used further to characterize the bubble chord length fluctuations, bubbling frequency and bubble size distributions. The effects of different models used to calculate gas-solid momentum exchange on fluidization behavior were investigated. The results showed that the predicted time-averaged αs distribution differed marginally and were in a satisfactory agreement with the corresponding measurements. However, the predicted bubbling frequency and bubble size distribution, in particular, the formation of large bubbles/slugs predicted using different drag models were considerably different and were not even in a qualitative agreement with the measurements. The modification proposed to the drag model in the present work led to an improvement in the predicted bubbling behavior and showed a qualitative agreement with the measurements. Further, simulations performed to investigate the effect of solid-phase frictional viscosity (μs,fr) showed that an increase in the solid-phase frictional pressure leads to an increase in μs,fr. Such an increase in μs,fr leads to compaction of the solid phase and to the formation of large bubbles/slugs, in line with what is observed experimentally. The predicted bubbling frequency and bubble size distribution were in a quantitative agreement with those measured using the ECT for different gas velocities.