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We report the first shock-tube experiments on dual-mode Richtmyer–Meshkov instability (RMI). An extended soap-film technique is adopted to generate a dual-mode gaseous interface such that its initial wavenumber (
) and phase of the fundamental waves are well controlled. By extracting interfacial contours from the distinct schlieren images, a Fourier analysis is performed from linear to weakly nonlinear stages and the growth of each basic wave is obtained. A noticeable difference between the growth of each basic mode and the corresponding single-mode RMI is observed, which suggests evident mode coupling effects in the dual-mode RMI. For dual-mode interfaces with in-phase
waves, the mode coupling suppresses (promotes) the growth of the
) mode, while for interfaces with anti-phase
modes, the growth of the
) mode is weakly influenced (evidently inhibited). However, for the combination of
waves, the mode coupling has a negligible influence on the growth of each basic wave. The modal theory of Haan (Phys. Fluids B, vol. 3, 1991, pp. 2349–2355), originally for multi-mode Rayleigh–Taylor instability, is reformulated for the dual-mode RMI, and it is found that this model overestimates the present experimental results for ignoring the nonlinear saturation. This model is then modified by accounting for both the mode coupling and nonlinear saturation, which well predicts the experimental results not only for the growth of the basic waves but also for the growth of second harmonics.
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
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
(which nominally corresponds to
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.
“Women’s Studies, Gender Studies, Feminist Studies,” with the theme of the subordination of women, is marked by diverse and overlapping intellectual traditions and movements. We take a non-Western perspective of this diversity. We use the terms interchangeably, as in the historical development from the earlier focus on Women’s Studies and more recent shift to Gender Studies in the West as well as in third world Women’s Studies, these disciplines have a close relationship with Feminism and the Women’s Movement and have gained from each other. The chapter covers issues including the Women’s Movements, Women’s Studies/Feminism, the different waves of feminism, feminist perspectives, feminist research / feminist methods, objectivity for feminist research and feminist theories. We cover theory and method for social science in general, but there is a section that features psychology specifically and highlights the different strands of feminism.
Birth weight influences not only brain development, but also mental health outcomes, including depression, but the underlying mechanism is unclear.
The phenotypic data of 12,872–91,009 participants (59.18–63.38% women) from UK Biobank were included to test the associations between the birth weight, depression, and brain volumes through the linear and logistic regression models. As birth weight is highly heritable, the polygenic risk scores (PRSs) of birth weight were calculated from the UK Biobank cohort (154,539 participants, 56.90% women) to estimate the effect of birth weight-related genetic variation on the development of depression and brain volumes. Finally, the mediation analyses of step approach and mediation analysis were used to estimate the role of brain volumes in the association between birth weight and depression. All analyses were conducted sex stratified to assess sex-specific role in the associations.
We observed associations between birth weight and depression (odds ratio [OR] = 0.968, 95% confidence interval [CI] = 0.957–0.979, p = 2.29 × 10−6). Positive associations were observed between birth weight and brain volumes, such as gray matter (B = 0.131, p = 3.51 × 10−74) and white matter (B = 0.129, p = 1.67 × 10−74). Depression was also associated with brain volume, such as left thalamus (OR = 0.891, 95% CI = 0.850–0.933, p = 4.46 × 10−5) and right thalamus (OR = 0.884, 95% CI = 0.841–0.928, p = 2.67 × 10−5). Additionally, significant mediation effects of brain volume were found for the associations between birth weight and depression through steps approach and mediation analysis, such as gray matter (B = –0.220, p = 0.020) and right thalamus (B = –0.207, p = 0.014).
Our results showed the associations among birth weight, depression, and brain volumes, and the mediation effect of brain volumes also provide evidence for the sex-specific of associations.
Six acidic dykes were discovered surrounding the Laiziling pluton, Xianghualing area, in the western Cathaysia Block, South China. A number of captured zircons are found in two of these acidic dykes. By detailed U–Pb dating, Lu–Hf isotopes and trace-element analysis, we find that these zircons have ages clustered at c. 2.5 Ga. Two acidic dyke samples yielded upper intersection point 206U/238Pb ages of 2505 ± 42 Ma and 2533 ± 22 Ma, and weighted mean 207Pb/206Pb ages of 2500 ± 30 Ma and 2535 ± 16 Ma. The majority of these zircons have high (Sm/La)N, Th/U and low Ce/Ce* ratios, indicating a magmatic origin, but some grains were altered by later hydrothermal fluid. Additionally, the magmatic zircons have high Y, U, heavy rare earth element, Nb and Ta contents, indicating that their host rocks were mainly mafic rocks or trondhjemite–tonalite–granodiorite rock series. Equally, their moderate Y, Yb, Th, Gd and Er contents also indicate that a mafic source formed in a continental volcanic-arc environment. These zircons have positive ϵHf(t) values (2.5–6.9) close to zircons from the depleted mantle, with TDM (2565–2741 Ma) and TDM2 (2608–2864 Ma) ages close to their formation ages, indicating that these zircons originated directly from depleted mantle magma, or juvenile crust derived from the depleted mantle in a very short period. We therefore infer that the Cathaysia Block experienced a crustal growth event at c. 2.5 Ga.
Parakmeria omeiensis is a Critically Endangered tree species in the family Magnoliaceae, endemic to south-west China. The tree is functionally dioecious, but little is known about the species’ status in the wild. We investigated the range, population size, age structure, habitat characteristics and threats to P. omeiensis. We located a total of 74 individuals in two populations on the steep slopes of Mount Emei, Sichuan province, growing under the canopy of evergreen broadleaved forest in well-drained gravel soil. A male-biased sex ratio, lack of effective pollinating insects, and habitat destruction result in low seed set and poor seedling survival in the wild. We have adopted an integrated conservation approach, including strengthening in situ conservation, cultivation of saplings, ex situ conservation and reintroduction, to protect this species. The successful conservation of P. omeiensis has important implications for the conservation of the genus Parakmeria and the family Magnoliaceae.
The present study aimed to evaluate the status of iodine nutrition and thyroid function in adults, to understand the distribution of thyroid disease in people with autoimmune thyroid disease (AITD) in different water iodine areas and to explore the relationship between serum iodine, urine iodine and thyroid function in people with AITD. A cross-sectional survey was conducted in areas of Shandong Province with different water iodine levels, and subsequently 1225 adults were enrolled from iodine-deficient (ID), iodine-adequate (IA) and iodine-excess (IE) areas. Urinary iodine, water iodine, salt iodine, serum iodine and thyroid function were measured. According to the urine iodine concentration, the ID and IA areas were defined as iodine sufficient and the IE area as iodine excessive. Urine iodine, serum iodine, free thyroxine (FT4) and thyroid-stimulating hormone (TSH) levels were comparatively higher in the IE area. The positive rate of thyroglobulin antibody (19·1 %) and the prevalence of AITD (21·8 %) were higher in the ID areas; the prevalence of subclinical hypothyroidism was lowest in the ID areas (7·3 %) and highest in the IE area (16·3 %). Among the AITD population, urinary iodine concentration, free triiodothyronine, FT4 and TSH had a non-linear correlation with serum iodine; abnormal TSH level, serum iodine concentration > 110 µg/l and goitre were risk factors for AITD in adults, especially females. Our data collectively suggest that universal salt iodisation has improved the iodine nutritional status of the population in ID areas in China. Non-step-by-step iodine fortification may induce the transformation of thyroid autoimmune diseases from recessive-to-dominant in susceptible people. Moreover, enhanced monitoring of thyroid function in people with AITD is important.
The coronavirus disease 2019 (COVID-19) outbreak caused by the severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2 virus) has been sustained in China since December 2019, and has become a pandemic. The mental health of frontline medical staff is a concern. In this study, we aimed to identify the factors influencing medical worker anxiety in China during the COVID-19 outbreak. We conducted a cross-sectional study to estimate the prevalence of anxiety among medical staff in China from 10 February 2020 to 20 February 2020 using the Zung Self-rating Anxiety Scale (SAS) to assess anxiety, with the criteria of normal (⩽49), mild (50–59), moderate (60–70) and severe anxiety (⩾70). We used multivariable linear regression to determine the factors (e.g. having direct contact when treating infected patients, being a medical staff worker from Hubei province, being a suspect case) for anxiety. We also used adjusted models to confirm independent factors for anxiety after adjusting for gender, age, education and marital status. Of 512 medical staff in China, 164 (32.03%) had had direct contact treating infected patients. The prevalence of anxiety was 12.5%, with 53 workers suffering from mild (10.35%), seven workers suffering from moderate (1.36%) and four workers suffering from severe anxiety (0.78%). After adjusting for sociodemographic characteristics (gender, age, education and marital status), medical staff who had had direct contact treating infected patients experienced higher anxiety scores than those who had not had direct contact (β value = 2.33, confidence interval (CI) 0.65–4.00; P = 0.0068). A similar trend was observed in medical staff from Hubei province, compared with those from other parts of China (β value = 3.67, CI 1.44–5.89; P = 0.0013). The most important variable was suspect cases with high anxiety scores, compared to non-suspect cases (β value = 4.44, CI 1.55–7.33; P = 0.0028). In this survey of hospital medical workers during the COVID-19 outbreak in China, we found that study participants experienced anxiety symptoms, especially those who had direct clinical contact with infected patients; as did those in the worst affected areas, including Hubei province; and those who were suspect cases. Governments and healthcare authorities should proactively implement appropriate psychological intervention programmes, to prevent, alleviate or treat increased anxiety.
In late December 2019, patients of atypical pneumonia due to an unidentified microbial agent were reported in Wuhan, Hubei Province, China. Subsequently, a novel coronavirus was identified as the causative pathogen which was named SARS-CoV-2. As of 12 February 2020, more than 44 000 cases of SARS-CoV-2 infection have been confirmed in China and continue to expand. Provinces, municipalities and autonomous regions of China have launched first-level response to major public health emergencies one after another from 23 January 2020, which means restricting movement of people among provinces, municipalities and autonomous regions. The aim of this study was to explore the correlation between the migration scale index and the number of confirmed coronavirus disease 2019 (COVID-19) cases and to depict the effect of restricting population movement. In this study, Excel 2010 was used to demonstrate the temporal distribution at the day level and SPSS 23.0 was used to analyse the correlation between the migration scale index and the number of confirmed COVID-19 cases. We found that since 23 January 2020, Wuhan migration scale index has dropped significantly and since 26 January 2020, Hubei province migration scale index has dropped significantly. New confirmed COVID-19 cases per day in China except for Wuhan gradually increased since 24 January 2020, and showed a downward trend from 6 February 2020. New confirmed COVID-19 cases per day in China except for Hubei province gradually increased since 24 January 2020, and maintained at a high level from 24 January 2020 to 4 February 2020, then showed a downward trend. Wuhan migration scale index from 9 January to 22 January, 10 January to 23 January and 11 January to 24 January was correlated with the number of new confirmed COVID-19 cases per day in China except for Wuhan from 22 January to 4 February. Hubei province migration scale index from 10 January to 23 January and 11 January to 24 January was correlated with the number of new confirmed COVID-19 cases per day in China except for Hubei province from 22 January to 4 February. Our findings suggested that people who left Wuhan from 9 January to 22 January, and those who left Hubei province from 10 January to 24 January, led to the outbreak in the rest of China. The ‘Wuhan lockdown’ and the launching of the first-level response to this major public health emergency may have had a good effect on controlling the COVID-19 epidemic. Although new COVID-19 cases continued to be confirmed in China outside Wuhan and Hubei provinces, in our opinion, these are second-generation cases.
The extent of intertidal flats in the Yellow Sea region has declined significantly in the past few decades, resulting in severe population declines in several waterbird species. The Yellow Sea region holds the primary stopover sites for many shorebirds during their migration to and from northern breeding grounds. However, the functional roles of these sites in shorebirds’ stopover ecology remain poorly understood. Through field surveys between July and November 2015, we investigated the stopover and moult schedules of migratory shorebirds along the southern Jiangsu coast, eastern China during their southbound migration, with a focus on the ‘Critically Endangered’ Spoon-billed Sandpiper Calidris pygmaea and ‘Endangered’ Nordmann’s Greenshank Tringa guttifer. Long-term count data indicate that both species regularly occur in globally important number in southern Jiangsu coast, constituting 16.67–49.34% and 64.0–80.67% of their global population estimates respectively, and it is highly likely that most adults undergo their primary moult during this southbound migration stopover. Our results show that Spoon-billed Sandpiper and Nordmann’s Greenshank staged for an extended period of time (66 and 84 days, respectively) to complete their primary moult. On average, Spoon-billed Sandpipers and Nordmann’s Greenshanks started moulting primary feathers on 8 August ± 4.52 and 27 July ± 1.56 days respectively, and their moult durations were 72.58 ± 9.08 and 65.09 ± 2.40 days. In addition, some individuals of several other shorebird species including the ‘Endangered’ Great Knot Calidris tenuirostris, ‘Near Threatened’ Bar-tailed Godwit Limosa lapponica, ‘Near Threatened’ Eurasian Curlew Numenius arquata and Greater Sand Plover Charadrius leschenaultii also underwent primary moult. Our work highlights the importance of the southern Jiangsu region as the primary moulting ground for these species, reinforcing that conservation of shorebird habitat including both intertidal flats and supratidal roosting sites in this region is critical to safeguard the future of some highly threatened shorebird species.
To explore the scope of metabolic syndrome (MetS) and its relationship to the major dietary patterns among an urbanised and semi-urbanised Tibetan population in transition from nomadic to settled settings.
Urbanised and semi-urbanised Tibetan adults (n 920, aged 18–90 years), who have moved from nomadic to settled living environments, answered questionnaires on food consumption frequency and lifestyle characteristics through structured face-to-face interviews and completed anthropometric measurement and metabolic biomarker tests.
MetS prevalence was 30·1 % in males and 32·1 % in females. Low HDL-cholesterol and central obesity were the leading metabolic abnormalities (86·3 and 55·8 %, respectively). Three major dietary patterns – urban, western and pastoral – were identified. Beef/mutton was an important food group for all three identified dietary patterns. In addition, the urban dietary pattern was characterised by frequent consumption of vegetables, tubers/roots and refined carbohydrates; the western pattern was characterised by sweetened drinks, snacks and desserts; and the pastoral pattern featured tsamba (roasted Tibetan barley), Tibetan cheese, butter tea/milk tea and whole-fat dairy foods. Individuals in the highest quintile of urban dietary pattern scores were found to be at a higher risk of developing MetS (OR 2·43, 95 % CI 1·41, 4·18) and central obesity (OR 1·91, 95 % CI 1·16, 3·14) after controlling for potential confounders.
MetS was common among urbanised and semi-urbanised Tibetan adult population in transition. The urban dietary pattern, in particular, was a risk factor for MetS. To prevent MetS, nutrition interventions need to be tailored to address the variety of local diet patterns to promote healthy eating.
Multiple neurotrophic factors, including vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF)-2, nerve growth factor (NGF) and insulin-like growth factor(IGF)-1, have been shown to play important roles in the pathophysiology of mood disorders. However, insufficient clinical data supporting the importance of these neurotrophic factors in mood disorders, especially manic episode, have made inconclusive to make a connection between these factors and the disorder.
This study intended to investigate possible peripheral biomarkers in serum of manic episode of bipolar disorder.
We aimed to investigate whether or not serum levels of VEGF, FGF-2, NGF and IGF-1 varied in manic state.
Serum levels of VEGF, FGF-2, NGF and IGF-1 were examined in 70 drug-naïve patients with manic episode of bipolar disorder (BM) as well as 50 healthy controls, using an ELISA method.
The mean serum levels of VEGF, FGF-2, NGF and IGF-1 were 168.13±225.61pg/ml, 279.09±378.62pg/ml, 61.38±171.67pg/ml and 162.01±72.00ng/ml in BM patients, and 140.80±143.71pg/ml, 275.46±235.29pg/ml, 36.34±15.14pg/ml and 138.90±80.11ng/ml in healthy controls, respectively. Serum levels of FGF-2, NGF and IGF-1 in patients were significantly higher than those in healthy controls (Z=−2.896, P=0.004; Z=− 2.050, P=0.040; Z=−2.188, P=0.029; respectively), although there was no statistical difference in the serum levels of VEGF between two groups (Z=-0.468, P=0.639). Moreover, serum levels of NGF in patients correlated with the duration of disorder (rs=−0.241, P=0.044).
The increase in serum levels of FGF-2, NGF and IGF-1 in manic state may reflect a neuroprotective role for these factors, and these factors may be considered biological markers for manic episode.
Findings for the roles of dairy products, Ca and vitamin D on ovarian cancer risk remain controversial. We aimed to assess these associations by using an updated meta-analysis. Five electronic databases (e.g. PubMed and Embase) were searched from inception to 24 December 2019. Pooled relative risks (RR) with 95 % CI were calculated. A total of twenty-nine case–control or cohort studies were included. For comparisons of the highest v. lowest intakes, higher whole milk intake was associated with increased ovarian cancer risk (RR 1·35; 95 % CI 1·15, 1·59), whereas decreased risks were observed for higher intakes of low-fat milk (RR 0·84; 95 % CI 0·73, 0·96), dietary Ca (RR 0·71; 95 % CI 0·60, 0·84) and dietary vitamin D (RR 0·80; 95 % CI 0·67, 0·95). Additionally, for every 100 g/d increment, increased ovarian cancer risks were found for total dairy products (RR 1·03; 95 % CI 1·01, 1·04) and for whole milk (RR 1·07; 95 % CI 1·03, 1·11); however, decreased risks were found for 100 g/d increased intakes of low-fat milk (RR 0·95; 95 % CI 0·91, 0·99), cheese (RR 0·87; 95 % CI 0·76, 0·98), dietary Ca (RR 0·96; 95 % CI 0·95, 0·98), total Ca (RR 0·98; 95 % CI 0·97, 0·99), dietary vitamin D (RR 0·92; 95 % CI 0·87, 0·97) and increased levels of circulating vitamin D (RR 0·84; 95 % CI 0·72, 0·97). These results show that whole milk intake might contribute to a higher ovarian cancer risk, whereas low-fat milk, dietary Ca and dietary vitamin D might reduce the risk.
Varicella is an acute respiratory infectious diseases, with high transmissibility and quick dissemination. In this study, an SEIR (susceptible-exposed-infected-recovered) dynamic model was established to explore the optimal prevention and control measures according to the epidemiological characteristics about varicella outbreak in a school in a central city of China. Berkeley Madonna 8.3.18 and Microsoft Office Excel 2010 software were employed for the model simulation and data management, respectively. The result showed that the simulated result of SEIR model agreed well with the reported data when β (infected rate) equal to 0.067. Models showed that the cumulative number of cases was only 13 when isolation adopted when the infected individuals were identified (assuming isolation rate was up to 100%); the cumulative number of cases was only two and the TAR (total attack rate) was 0.56% when the vaccination coefficient reached 50%. The cumulative number of cases did not change significantly with the change of efficiency of ventilation and disinfection, but the peak time was delayed; when δ (vaccination coefficient) = 0.1, m (ventilation efficiency) = 0.7 or δ = 0.2, m = 0.5 or δ = 0.3, m = 0.1 or δ = 0.4 and above, the cumulative number of cases would reduce to one case and TAR would reduce to 0.28% with combined interventions. Varicella outbreak in school could be controlled through strict isolation or vaccination singly; combined interventions have been adopted when the vaccination coefficient was low.
Captioned video is widely used to enhance second language (L2) learners’ exposure to oral input beyond the classroom setting, and captioning has been found to provide an instantaneous, useful visual aid for parsing and understanding L2 oral discourse. Nevertheless, a meta-analysis has shown that captioning exerts a selective effect on L2 learners with different profiles. This study investigated whether L2 learners’ modality preferences (visual vs. auditory) and working memory capacity (high vs. low) would modulate the effect of full captions on L2 listening outcome. Results from 60 participants revealed that both cognitive variables affected their L2 listening to different extents. Notably, working memory capacity modulates the impact of L2 learners’ preferred modality on their listening outcome. Modality preference did not exert any significant impact on the listening outcome of L2 learners with lower working memory capacity. For L2 learners with high working memory capacity, their modality preference played a pivotal role in modulating their listening outcome; in this case, auditory learners had the best listening performance viewing the video without captions, whereas visual learners did best when watching the captioned video. These findings speak to the need for taking individual differences into consideration when employing captioned videos.
Chlamydia spp. are a group of obligate intracellular pathogens causing a number of diseases in animals and humans. Avian chlamydiosis (AC), caused by Chlamydia psittaci (C. psittaci) as well as new emerging C. avium, C. gallinacea and C. ibidis, have been described in nearly 500 avian species worldwidely. The Crested Ibis (Nipponia nippon) is a world endangered avian species with limited population and vulnerable for various infections. To get a better understanding of the prevalence of Chlamydia spp. in the endangered Crested Ibis, faecal samples were collected and analysed. The results confirmed that 20.20% (20/99) of the faecal samples were positive for Chlamydiaceae and were identified as C. ibidis with co-existence of C. psittaci in one of the 20 positive samples. In addition, ompA sequence of C. psittaci obtained in this study was classified into the provisional genotype Matt116, while that of C. ibidis showed high genetic diversity, sharing only 77% identity with C. ibidis reference strain 10-1398/6. We report for the first time the presence of C. ibidis and C. psittaci in the Crested Ibis, which may indicate a potential threat to the endangered birds and should be aware of the future protection practice.
Richtmyer–Meshkov instability of the SF6 gas layer surrounded by air is experimentally investigated. Using the soap film technique, five kinds of gas layer with two sharp interfaces are generated such that the development of each individual interface is highlighted. The flow patterns are determined by the amplitudes and phases of two corrugated interfaces. For a layer with both interfaces planar, the interface velocity shows that the reflected rarefaction waves from the second interface accelerate the first interface motion. For a layer with the second interface corrugated but the first interface planar, the reflected rarefaction waves make the first interface develop with the same phase as the second interface. For a layer with the first interface corrugated but the second interface planar, the rippled shock seeded from the first interface makes the second interface develop with the same phase as the first interface and the layer evolves into an ‘upstream mushroom’ shape. For two interfaces corrugated with opposite (the same) phase but a larger amplitude for the first interface, the layer evolves into ‘sinuous’ shape (‘bow and arrow’ shape, which has never been observed previously). For the interface amplitude growth in the linear stage, the waves’ effects are considered in the model to give a better prediction. In the nonlinear stage, the effect of the rarefaction waves on the first interface evolution is quantitatively evaluated, and the nonlinear growth is well predicted. It is the first time in experiments to quantify the interfacial instability induced by the rarefaction waves inside the heavy gas layer.