Nanofluid as a special thermal transporting medium has recently received unprecedented attention due to its improved heat transfer performance compared to conventional fluids. Numerous researches have been conducted on the natural convection characteristics of different nanofluids in various configurations of cavities due to the important applications of natural convection in environmental, petrochemical, medical, aviation and space technology, industrial and many more areas. The emergence of a magnetic field as a tool for the manipulation of convective flow and heat transfer behaviours of nanofluids in non-square enclosures has been extensively reviewed. The influence of several variables such as controlling parameters, heat distribution methods, thermal and concentration boundary conditions, magnetic field types, numerical methods, correlation types, nanofluid types, heaters types, numbers and length, and slip conditions, etc., on the magnetohydrodynamic (MHD) natural convection flow and heat transfer behaviours of nanofluid in non-square cavities has been given great attention and brought to the spotlight for discussion. The concepts of bioconvection, micro-polar nanofluid, bio-nanofluid (green nanofluid), ionic nanofluid, and hybrid nanofluid have also been discussed for the first time in relation to natural convection. Special cases of MHD natural convection in non-square cavities involving hybrid nanofluids and micro-polar nanofluids are also presented herein. The application of several numerical methods (which is the major approach studied so far) to investigate the hydromagnetic behaviours of nanofluids in non-square cavities is the focus of this work.
In this study, the viscosity of MgO-Water nanofluid in a different volume fraction of nanoparticles, temperatures, and shear rates has been predicted by Artificial Neural Networks (ANNs) and surface methods. In the ANN method, an algorithm is proposed to select the best neuron number for the hidden layer. In the fitting method, a surface is proposed for each volume fraction of nanoparticles, and finally, the results of ANN and surface fitting method have been compared. It can be observed that, increasing the volume fraction from 0.07% to 1.25% at temperatures of 25, 30, 40, 50, and 60 °C resulted in about two-fold increase in viscosity. Also, the best network has 24 neurons in the hidden layer. It can be seen that for a network with 24 neurons in the hidden layer has the best overall correlation, and this coefficient is 0.999035. The mean absolute value of errors in ANN and fitting method are 0.0118 and 0.0206, respectively.
We introduce a straightforward method for the preparation of novel starch-based ultramicroporous carbons (SCs) that demonstrate high CH4 uptake and excellent CH4/N2 selectivity. These SCs are derived from a combination of starch and 1-6 wt. % of acrylic acid, and the resulting materials are amenable to surface cation exchangeability as demonstrated by the formation of highly dispersed K+ in carbon precursors. Following activation, these SCs contain ultramicropores with narrow pore-size distributions of <0.7 nm, leading to porous carbon-rich materials that exhibit CH4 uptake values as high as 1.86 mmol/g at 100 kPa and 298 K, the highest uptake value for CH4 to date, with the IAST-predicted CH4/N2 selectivity up to 5.7. Both the potential mechanism for the formation of narrow pores and the origin of the favorable CH4 adsorption properties are discussed and examined. This work may potentially guide future designs for carbon-rich materials with excellent gas adsorption properties.
Bubble formation from a downward-pointing capillary nozzle was investigated in this study. The experiments were conducted at gas flow rate of 40-5400 mL/h and inner nozzle radius of 0.030-0.255 mm. Experimental results show that microbubbles were formed continuously at moderate Weber number, which was not reported in pervious investigations with injecting gas through an upward-pointing capillary nozzle. High-speed visualization indicates that the formation of microbubbles arises from the convergence of the capillary waves induced by the partial coalescence of larger bubbles. A bubbling regime map is given to identify the critical conditions for the formation of microbubbles. In the present air-water experiments, the generated microbubbles are 20-170 μm in diameter. From experimental data, a scaling law for microbubble size is proposed as a function of Weber and Bond numbers.
On the example of forty ion pairs, the study demonstrates how the core-level binding energy values can be calculated and used to plot theoretical spectra at a low computational cost using density functional theory methods. Three approaches for obtaining the binding energy values are based on delta Kohn–Sham (ΔKS) calculations, 1s Kohn–Sham orbital energies, and atomic charges. The ΔKS results show a good agreement between the available experimental X-ray photoelectron data. 1s Kohn–Sham orbital energies and atomic charges also correlate with the ΔKS results.
Pathogen persistence in host communities is influenced by a hierarchy of heterogeneities from individual host to landscape-level attributes, but isolating the relative contributions of these heterogeneities is challenging. We developed theory to partition the influence of host species, habitat patches, and landscape connectivity on pathogen persistence within host-pathogen metacommunities. We used the framework to quantify the contributions of host species composition and habitat patch identity on the persistence of an amphibian pathogen across the landscape. By sampling over 11,000 hosts of six amphibian species, we found that a single host species could maintain the pathogen in 91% of the metacommunities we observed. Moreover, this dominant maintenance species contributed, on average, twice as much to landscape-level pathogen persistence compared to the most influential source patch in a metacommunity. Our analysis demonstrates substantial inequality in how species and patches contribute to pathogen persistence, with important implications for targeted disease management.
Phenotypic plasticity can allow animals to adapt their behaviour, such as their mating effort, to their social and sexual environment. However, this relies on the individual receiving accurate and reliable cues of the environmental conditions. This can be achieved via the receipt of multi-component cues, which may provide redundancy and robustness. Male Drosophila melanogaster detect presence of rivals via combinations of any two or more redundant cue components (sound, smell and touch) and respond by extending their subsequent mating duration, which is associated with higher reproductive success. Although alternative combinations of cues of rival presence have previously been found to elicit equivalent increases in mating duration and offspring production, their redundancy in securing success under sperm competition has not previously been tested. Here, we explicitly test this by exposing male D. melanogaster to alternative combinations of rival cues and examining reproductive success in both the presence and absence of sperm competition. The results supported previous findings of redundancy of cues in terms of behavioural responses. However, there was no evidence of reproductive benefits accrued by extending mating duration in response to rivals. The lack of identifiable fitness benefits of longer mating under these conditions, both in the presence and absence of sperm competition, contrasted with some previous results, but could be explained by: 1) damage sustained from aggressive interactions with rivals leading to reduced ability to increase ejaculate investment, 2) presence of features of the social environment, such as male and female mating status, that obscured the fitness benefits of longer mating, 3) decoupling of behavioural investment with fitness benefits.
Numerous socio-economic activities depend on the seasonal rainfall and groundwater recharge cycle across the Central American Isthmus. Population growth and unregulated land use changes resulted in extensive surface water pollution and a large dependency on groundwater resources. This work combines stable isotope variations in rainfall, surface water, and groundwater of Costa Rica, Nicaragua, El Salvador, and Honduras to develop a regionalized rainfall isoscape, isotopic lapse rates, spatial-temporal isotopic variations, and air mass back trajectories determining potential mean recharge elevations, moisture circulation patterns, and surface water-groundwater interactions. Intra-seasonal rainfall modes resulted in two isotopically depleted incursions (W-shaped isotopic pattern) during the wet season and two enriched pulses during the Mid-Summer Drought and the months of the strongest trade winds. Notable isotopic sub-cloud fractionation and near-surface secondary evaporation were identified as common denominators within the Central American Dry Corridor. Groundwater and surface water isotope ratios depicted the strong orographic separation into the Caribbean and Pacific domains, mainly induced by the governing moisture transport from the Caribbean Sea, complex rainfall producing systems across the N-S mountain range, and the subsequent mixing with local evapotranspiration, and, to a lesser degree, the eastern Pacific Ocean fluxes. Groundwater recharge was characterized by a) depleted recharge in highland areas (72.3%), b) rapid recharge via preferential flow paths (13.1%), and enriched recharge due to near-surface secondary fractionation (14.6%). Median recharge elevation ranged from 1,104 to 1,979 m asl. These results are intended to enhance forest conservation practices, inform water protection regulations, and facilitate water security and sustainability planning in the Central American Isthmus.
Since news of COVID-19 outbreak hit the mainstream media, I have received several calls from acquaintances about if and how they should be worried. I suspect many readers of the Journal of Evaluation in Clinical Practice have experienced the same. What makes communicating the risk difficult can be illustrated through a recent assignment I gave to my undergraduate class focused on how we use science in public policy. I asked the students to identify claims in the media regarding the virus and then search the literature to assess the level of support for such claims. Suffice it to say, they found several claims unsupported, and several others to be inconclusive. Not very good grounding for providing definitive (or even satisfying) advice.
In this paper, the Shannon entropy and Fisher information are studied for the screened Kratzer potential model (SKP). We calculated the position and momentum entropies for the screened Kratzer potential for its ground states as well as the first excited state. Our result shows that the sum of the position and momentum entropies satisfies the lower bound Berkner, Bialynicki–Birula and Mycieslki (BBM) inequality. Also, our results showed that decreasing Shannon entropy in the position space was complemented with an increasing Shannon entropy in the momentum space. Similarly, we evaluated for Fisher information and show that the Stam, Cramer-Rao inequalities are satisfied. The squeezing phenomena were also observed for certain values of the screening parameter α.
Background: Lack of time has consistently been reported as a major barrier to effective research evidence-uptake into clinical practice. There has been no research to our knowledge that explores time as a barrier within the Transtheoretical model of Stages of Change (SoC), to better understand the processes of physiotherapists’ uptake of clinical practice guidelines (CPG). This paper explores the concept of lack of time as a barrier for CPG uptake for physiotherapists at different SoC. Methods: A 6-step process is presented to determine the best-fit SoC for 31 physiotherapy interviewees. This process used an amalgamation of interview findings and socio-demographic data, which was layered onto the SoC and previously identified time-barriers to CPG uptake (few staff; high workload; access to CPGs; evidence-based practice as priority in clinical practice; “time is money” attitude; and knowledge on the use of CPGs). Results: The analysis process highlighted the complexities of assigning individuals to a SoC. A model of time management for better CPG uptake is proposed which is a novel approach to assist evidence implementalists and clinicians alike to determine how to progress through the SoC and barriers to improve CPG uptake. Conclusions: To the authors’ knowledge, this is the first attempt at exploring the construct of (lack of) time for CPG-uptake in relation to the physiotherapists’ readiness to behaviour change. This study shows that ‘lack of time’ is a euphemism for quite different barriers, which map to different stages of readiness to embrace current best evidence into physiotherapy practice. By understanding what is meant by ‘lack of time’, it may indicate specific support required by physiotherapists at different stages of changing these behaviours.
Since December 2019, a new coronavirus (COVID-19) infection has rapidly become prevalent in central China . On the basis of knowledge obtained from a previous coronavirus outbreak , pregnant women are believed to be susceptible to this virus. Once a maternal infection of 2019-nCoV is suspected or confirmed, childbirth becomes complicated and challenging. Efficient obstetric treatment is required, and is key to optimizing the prognosis for both mother and child. Care should be taken in determination of the timing of delivery, assessment of the indications for caesarean section, preparation of the delivery room to prevent infection, choice of the type of anesthesia, and newborn management.
Plants employ a diverse set of defense mechanisms to mediate interactions with insects and fungi. These relationships can leave lasting impacts on host plant genome structure such as rapid expansion of gene families through tandem duplication. These genomic signatures provide important clues about the complexities of plant/biotic stress interactions and evolution. We used a pseudo-backcross hybrid family to identify Quantitative Trait Loci (QTL) controlling associations between Populus trees and several common Populus diseases and insects. Using whole genome sequences from each parent, we identified candidate genes that may mediate these interactions. Candidates were partially validated using mass spectrometry to identify corresponding QTL for defensive compounds. We detected significant QTL for two interacting fungal pathogens and three insects. The QTL intervals contained candidate genes potentially involved in physical and chemical mechanisms of host-plant resistance and susceptibility. In particular, we identified overlapping QTLs for a phenolic glycoside and Phyllocolpa sawfly abundance. There was also significant enrichment of recent tandem duplications in the genomic intervals of the native parent, but not the exotic parent. Tandem gene duplication may be an important mechanism for rapid response to biotic stressors, enabling trees with long juvenile periods to reach maturity despite many coevolving biotic stressors.
In this letter, two time delay dynamic models, TDD-NCP model and Fudan-CCDC model, are introduced to track the data of COVID-19. The TDD-NCP model is developed recently by Cheng's group group in Fudan and SUFE. The TDD-NCP model introduced the time delay process into the differential equations to describe the latent period of the epidemic. The Fudan-CDCC model is established when Wenbin Chen suggested to determine the kernel functions in the TDD-NCP model by the public data from CDCC. By the public data of the cumulative confirmed cases in different regions in China and different countries, these models can clearly illustrate that the containment of the epidemic highly depends on early and effective isolations.
Background: Most studies on the transition from pediatric to adult care focus on practices at a single institution. We examine the transition for young adults with type 1 diabetes across an entire Canadian province with a small, mostly rural population: Newfoundland and Labrador (NL). Our aim is to determine a comprehensive picture of how transition is occurring in one jurisdiction and explore potential methods for improvement. Methods: A provincial diabetes database and hospital admission data were reviewed for a cohort of young adults who transitioned into adult care to determine the number of transfers occurring, patient characteristics, and the number of diabetes-related hospitalizations. Semi-structured interviews with pediatric and adult diabetes providers were conducted to determine the current process of transition and identify ways for improvement, including the potential role of family physicians. Results: Between 2008 and 2013, 93 patients with type 1 diabetes transitioned into adult care. Fifteen interviews were conducted across the province’s four regional health authorities. Various models of transition care are being employed, reflecting staff and resource availability. While no structured transition program was identified, many providers were comfortable with their current transition processes. Suggested improvements included more structured processes, shared educational resources, and a dedicated transfer clinic. Conclusions: In a province with a relatively small number of patients who transition out of pediatric care annually, we found different approaches for transitioning them into adult care, but this variation may not negatively impact patient outcomes.