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We present a numerical study of the flow states and reversals of the large-scale circulation (LSC) in a two-dimensional circular Rayleigh–Bénard cell. Long-time direct numerical simulations are carried out in the Rayleigh number ($Ra$) range $10^{7} \leqslant Ra \leqslant 10^{8}$ and Prandtl number ($Pr$) range $2.0 \leqslant Pr \leqslant 20.0$. We found that a new, long-lived, chaotic flow state exists, in addition to the commonly observed circulation states (the LSC in the clockwise and counterclockwise directions). The circulation states consist of one primary roll in the middle and two secondary rolls near the top and bottom circular walls. The primary roll becomes stronger and larger, while the two secondary rolls diminish, with increasing $Ra$. Our results suggest that the reversal of the LSC is accompanied by the secondary rolls growing, breaking the primary roll and then connecting to form a new primary roll with reversed direction. We mapped out the phase diagram of the existence of the LSC and the reversal in the $Ra\text{--}Pr$ space, which reveals that the flow is in the circulation states when $Ra$ is large and $Pr$ is small. The reversal of the LSC can only occur in a limited $Pr$ range. The phase diagram can be understood in terms of competition between the thermal and viscous diffusions. We also found that the internal flow states manifested themselves into global properties such as Nusselt and Reynolds numbers.
Vertex-primitive self-complementary graphs were proved to be affine or in product action by Guralnick et al. [‘On orbital partitions and exceptionality of primitive permutation groups’, Trans. Amer. Math. Soc.356 (2004), 4857–4872]. The product action type is known in some sense. In this paper, we provide a generic construction for the affine case and several families of new self-complementary Cayley graphs are constructed.
The Belt and Road Initiative (BRI) has brought with it an unprecedented number of agreements. BRI agreements consist of primary agreements (particularly MOUs) and secondary agreements (like performance agreements). They are a distinct, landmark feature of the BRI. Focusing on primary agreements and their close link with secondary agreements, this paper explores the following questions: What are the legal status and characteristics of primary agreements? Why are they adopted by China? What challenges do they face? BRI primary agreements can be regarded as a form of soft law, but that repurposes soft law characteristics for project development rather than rule development. BRI primary agreements have the following unique characteristics: (i) minimal legalization, (ii) a coordinated, project-based nature, and (iii) a hub-and-spoke network structure. While BRI primary agreements benefit from the advantages of soft law (e.g., reduced contracting costs, flexibility), they face challenges including those concerning underlying interests and their effectiveness.
To explore the effect of manno-oligosaccharide (MOS) on intestinal health in weaned pigs upon enterotoxigenic Escherichia coli K88 (ETEC) challenge, thirty-two male weaned pigs were randomly assigned into four groups. Pigs fed with a basal diet or basal diet containing MOS (0·6 g/kg) were orally infused with ETEC or culture medium. Results showed that MOS significantly elevated the digestibility of crude protein and gross energy in both ETEC-challenged and non-challenged pigs (P < 0·05). MOS also elevated serum concentrations of IgA and IgM (P < 0·05), but decreased serum concentrations of TNF-α, IL-1β and IL-6 (P < 0·05) in ETEC-challenged pigs. Interestingly, MOS increased villus height and the ratio of villus height:crypt depth in duodenum and ileum (P < 0·05). MOS also increased duodenal sucrase and ileal lactase activity in ETEC-challenged pigs (P < 0·05). MOS decreased the abundance of E. coli, but increased the abundance of Lactobacillus, Bifidobacterium and Bacillus in caecum (P < 0·05). Importantly, MOS not only elevated the expression levels of zonula occludens-1 (ZO-1), claudin-1 and GLUT-2 in duodenum (P < 0·05) but also elevated the expression levels of ZO-1, GLUT-2 and L-type amino acid transporter-1 in ileum (P < 0·05) upon ETEC challenge. These results suggested that MOS can alleviate inflammation and intestinal injury in weaned pigs upon ETEC challenge, which was associated with suppressed secretion of inflammatory cytokines and elevated serum Ig, as well as improved intestinal epithelium functions and microbiota.
Asymmetric information and diverse preferences for reform create an agency problem between opposition leaders and citizens. Dissatisfied citizens are unsure of how bad the current situation is but infer this information from the scale of the leader’s reform proposal. Because radical leaders have an incentive to exaggerate and mislead, to command credibility, they must paradoxically radicalize the proposal further as a way of signaling the necessity of change. Radicalism motivated by signaling is costly, as it reduces a movement’s chances of success. This mechanism also contributes to leadership radicalization when the leaders of movements arise as a compromise among diverse interests.
Since Singapore’s inception, the national economic playing field has always been tightly coupled with the global economy. Policy imperatives are framed and contested within the resulting global–local nexus. Education, especially language-in-education, has been and continues to be a key player in the intertwining of economic, political, and cultural imperatives at this nexus. In this chapter, we consider English language teacher education within the global–local nexus framed by globalization. First, we provide some context on English Language (EL) education in Singapore. This is followed by an overview of the teacher education system, with a focus on education for prospective EL teachers. We then discuss some of the challenges posed by Singapore’s particular view on globalization, the contradictions in that view, and their connection with EL learning and teacher education. We end by exploring some possible ways forward.
We give a formula for the class number of an arbitrary complex mutliplication (CM) algebraic torus over
$\mathbb {Q}$
. This is proved based on results of Ono and Shyr. As applications, we give formulas for numbers of polarized CM abelian varieties, of connected components of unitary Shimura varieties and of certain polarized abelian varieties over finite fields. We also give a second proof of our main result.
The risk of environmental contamination by severe acute respiratory coronavirus virus 2 (SARS-CoV-2) in the intensive care unit (ICU) is unclear. We evaluated the extent of environmental contamination in the ICU and correlated this with patient and disease factors, including the impact of different ventilatory modalities.
Methods:
In this observational study, surface environmental samples collected from ICU patient rooms and common areas were tested for SARS-CoV-2 by polymerase chain reaction (PCR). Select samples from the common area were tested by cell culture. Clinical data were collected and correlated to the presence of environmental contamination. Results were compared to historical data from a previous study in general wards.
Results:
In total, 200 samples from 20 patient rooms and 75 samples from common areas and the staff pantry were tested. The results showed that 14 rooms had at least 1 site contaminated, with an overall contamination rate of 14% (28 of 200 samples). Environmental contamination was not associated with day of illness, ventilatory mode, aerosol-generating procedures, or viral load. The frequency of environmental contamination was lower in the ICU than in general ward rooms. Eight samples from the common area were positive, though all were negative on cell culture.
Conclusion:
Environmental contamination in the ICU was lower than in the general wards. The use of mechanical ventilation or high-flow nasal oxygen was not associated with greater surface contamination, supporting their use and safety from an infection control perspective. Transmission risk via environmental surfaces in the ICUs is likely to be low. Nonetheless, infection control practices should be strictly reinforced, and transmission risk via droplet or airborne spread remains.
Monochamus alternatus Hope (Coleoptera: Cerambycidae) warrants attention as a dominant transmission vector of the pinewood nematode, and it exhibits tolerance to high temperature. Heat shock protein 70 (HSP70) family members, including inducible HSP70 and heat shock cognate protein 70 (HSC70), are major contributors to the molecular chaperone networks of insects under heat stress. In this regard, we specifically cloned and characterized three MaltHSP70s and three MaltHSC70s. Bioinformatics analysis on the deduced amino acid sequences showed these genes, having close genetic relationships with HSP70s of Coleopteran species, collectively shared conserved signature structures and ATPase domains. Subcellular localization prediction revealed the HSP70s of M. alternatus were located not only in the cytoplasm and endoplasmic reticulum but also in the nucleus and mitochondria. The transcript levels of MaltHSP70s and MaltHSC70s in each state were significantly upregulated by exposure to 35–50°C for early 3 h, while MaltHSP70s reached a peak after exposure to 45°C for 2–3 h in contrast to less-upregulated MaltHSC70s. In terms of MaltHSP70s, the expression threshold in females was lower than that in males. Also, both fat bodies and Malpighian tubules were the tissues most sensitive to heat stress in M. alternatus larvae. Lastly, the ATPase activity of recombinant MaltHSP70-2 in vitro remained stable at 25–40°C, and this recombinant availably enhanced the thermotolerance of Escherichia coli. Overall, our findings unraveled HSP70s might be the intrinsic mediators of the strong heat tolerance of M. alternatus due to their stabilized structure and bioactivity.
We present an experimental study on controlling the number of vortices and the torque in a Taylor–Couette flow of water for Reynolds numbers from 660 to 1320. Different flow states are achieved in the annulus of width
$d$
between the inner rotating and outer stationary cylinders through manipulating the initial height of the water annulus. We show that the torque exerted on the inner cylinder of the Taylor–Couette system can be reduced by up to 20 % by controlling the flow at a state where fewer than the nominal number of vortices develop between the cylinders. This flow state is achieved by starting the system with an initial water annulus height
$h_0$
(which nominally corresponds to
$h_0/d$
vortices), then gradually adding water into the annulus while the inner cylinder keeps rotating. During this filling process the flow topology is so persistent that the number of vortices does not increase; instead, the vortices are greatly stretched in the axial (vertical) direction. We show that this state with stretched vortices is sustainable until the vortices are stretched to around 2.05 times their nominal size. Our experiments reveal that by manipulating the initial height of the liquid annulus we are able to generate different flow states and demonstrate how the different flow states manifest themselves in global momentum transport.
Supportive housing, including retirement homes and assisted living, is increasingly touted as a suitable living option for Canadian older adults. This scoping review describes the nature and content of studies that explore underlying factors that motivate older adults to relocate to supportive housing. We conducted a search of PubMed, Cumulative Index of Nursing and Allied Health Literature (CINAHL), Web of Science, and PsycINFO, which identified 34 articles for review. Articles reviewed employed a variety of methods and guiding theoretical frameworks, of which the push and pull framework appeared to be most common. This review suggests that health and functional deficits are important reasons for relocation to supportive housing for older adults. Further longitudinal data are required to more comprehensively describe medical and social determinants for relocation and its consequences, in order to better describe this growing population and better align policies with the needs of older adults contemplating or undergoing relocation.
To examine the gestational weight gain (GWG) trajectory and its possible association with pregnancy outcomes.
Design:
GWG trajectories were identified using the latent class growth model. Binary logistic regression was performed to examine the associations between adverse pregnancy outcomes and these trajectories.
Setting:
Negeri Sembilan, Malaysia.
Participants:
Two thousand one hundred ninety-three pregnant women.
Results:
Three GWG trajectories were identified: ‘Group 1 – slow initial GWG but followed by drastic GWG’, ‘Group 2 – maintaining rate of GWG at 0·58 kg/week’ and ‘Group 3 – maintaining rate of GWG at 0·38 kg/week’. Group 1 had higher risk of postpartum weight retention (PWR) (adjusted OR (AOR) 1·02, 95 % CI 1·01, 1·04), caesarean delivery (AOR 1·03, 95 % CI 1·01, 1·04) and having low birth weight (AOR 1·04, 95 % CI 1·02, 1·05) compared with group 3. Group 2 was at higher risk of PWR (AOR 1·18, 95 % CI 1·16, 1·21), preterm delivery (AOR 1·03, 95 % CI 1·01, 1·05) and caesarean delivery (AOR 1·02, 95 % CI 1·01, 1·03), but at lower risk of having small-for-gestational-age infants (AOR 0·97, 95 % CI 0·96, 0·99) compared with group 3. The significant associations between group 1 and PWR were observed among non-overweight/obese women; between group 1 and caesarean delivery among overweight/obese women; group 2 with preterm delivery and caesarean delivery were only found among overweight/obese women.
Conclusions:
Higher GWG as well as increasing GWG trajectories was associated with higher risk of adverse pregnancy outcomes. Promoting GWG within the recommended range should be emphasised in antenatal care to prevent the risk of adverse pregnancy outcomes.
We give a fully polynomial-time randomized approximation scheme (FPRAS) for the number of bases in bicircular matroids. This is a natural class of matroids for which counting bases exactly is #P-hard and yet approximate counting can be done efficiently.
Disasters are often unforeseen events. Hospitals form a critical component of any country’s disaster management medical support system. To ensure optimal operations, minimize chaos, and allow flexibility in response, planning and practice are crucial. Singapore Health Services (SingHealth) collaborated with Hasanuddin University (UnHas) in Makassar, Indonesia, to develop a Hospital Disaster Medical Support (HDMS) program for the province of South Sulawesi, Indonesia. An assessment of the needs of the hospitals in Makassar, Indonesia, for disaster preparedness was carried out. A curriculum for the HDMS program was developed based on the assessment. Discussions with stakeholders of various hospitals were held for the implementation of this program. A total of 310 participants were trained in this program over the two-year period. The feedback from the participants was positive. The exercises provided a more realistic simulation of the concepts of hospital management in a disaster situation. Up to 73 persons were also trained as program instructors during this period. The development of the cadre of instructors in hospital disaster medical support will likely help sustain the program for the next few years.