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This paper presents a numerical study on the flow around two tandem circular cylinders beneath a free surface at a Reynolds number of $180$. The free-surface effects on the wake dynamics and hydrodynamic forces are investigated through a parametric study, covering a parameter space of gap ratios from $0.20$ to $2.00$, spacing ratios from $1.50$ to $4.00$ and Froude numbers from $0.2$ to $0.8$. A jet-like flow accompanied by a shear layer of positive vorticity separating from the free surface is formed in the wake at small gap ratios, which significantly alters the wake pattern through its dynamic behaviours. At shallow submergence depths, the three-dimensional wake transitions from mode B to mode A as the distance between the cylinders increases. As submergence depth increases, the wavy deformation of the primary vortex cores disappears in the wake, and the flow transitions to a two-dimensional state. Higher Froude numbers can extend the effect of the free surface to deeper submergence depths. The critical spacing ratio tends to be larger at higher Froude numbers. Furthermore, the free-surface deformation is examined. The free-surface profile typically comprises a hydraulic jump immediately ahead of the upstream cylinder, trapped waves in the vicinity of the two tandem cylinders and well-defined travelling waves on the downstream side. The frequencies of the waves cluster around the vortex shedding frequency, indicating a close association between the generation of waves and the vortex shedding process.
The technique of inter-simple sequence repeat-polymerase chain reaction (ISSR-PCR) was used to fingerprint blackgram (Vigna mungo) genotypes in order to differentiate them at a molecular level. Twenty-four primers were used to analyse 11 blackgram genotypes. The genotypes used in the study could be differentiated based on combined amplification profiles generated by two primers (UBC primer numbers 808 (AG)8C and 826 (AC)8C). It was observed that 3′-anchored repeat primers based on (AG) and (GA) repeats amplified a greater number of bands than 3′-anchored repeat primers of (CA) and (AC) repeats. This result perhaps indicates that GA/AG repeats are more frequent than CA/AC repeats in the blackgram genome.
An international consortium of radiocarbon laboratories has established the origin of the Church of St. Margaret of Antioch in Kopčany (Slovakia), because its age was not well known from previous investigations. In total, 13 samples of charcoal, wood, mortar, and plaster were analyzed. The 14C results obtained from the different laboratories, as well as between the different sample types, were in good agreement. Resulting the final 14C calibrated age of the Church, based on dating a single piece of a wooden levelling rod is 774–884 AD (95.4% confidence level), which is in very good agreement with Bayesian modeling result based on dating of wood, charcoal and mortar samples (788–884 AD, 95.4% confidence level). The probability distribution from OxCal calibration shows that 79% of the probability distribution lies in the period before 863 AD, implying that the Church could have been constructed before the arrival of Constantine (St. Cyril) and St. Methodius to Great Moravia. If we take as the terminus post quem the documented date of consecration of the church in Nitrava (828 AD), the Bayesian modeling suggests the age of the Church in the range of 837–884 AD (95.4% confidence level). Although the 14C results have very good precision, the specific plateau shape of the calibration curve in this period caused a wide range of the calibrated age. The Church represents, together with the St. George’s Rotunda in Nitrianska Blatnica, probably the oldest standing purpose-built Christian church in the eastern part of Central Europe.
Not all the information in a turbulent field is relevant for understanding particular regions or variables in the flow. Here, we present a method for decomposing a source field into its informative $\boldsymbol {\varPhi }_{I}(\boldsymbol {x},t)$ and residual $\boldsymbol {\varPhi }_{R}(\boldsymbol {x},t)$ components relative to another target field. The method is referred to as informative and non-informative decomposition (IND). All the necessary information for physical understanding, reduced-order modelling and control of the target variable is contained in $\boldsymbol {\varPhi }_{I}(\boldsymbol {x},t)$, whereas $\boldsymbol {\varPhi }_{R}(\boldsymbol {x},t)$ offers no substantial utility in these contexts. The decomposition is formulated as an optimisation problem that seeks to maximise the time-lagged mutual information of the informative component with the target variable while minimising the mutual information with the residual component. The method is applied to extract the informative and residual components of the velocity field in a turbulent channel flow, using the wall shear stress as the target variable. We demonstrate the utility of IND in three scenarios: (i) physical insight into the effect of the velocity fluctuations on the wall shear stress; (ii) prediction of the wall shear stress using velocities far from the wall; and (iii) development of control strategies for drag reduction in a turbulent channel flow using opposition control. In case (i), IND reveals that the informative velocity related to wall shear stress consists of wall-attached high- and low-velocity streaks, collocated with regions of vertical motions and weak spanwise velocity. This informative structure is embedded within a larger-scale streak–roll structure of residual velocity, which bears no information about the wall shear stress. In case (ii), the best-performing model for predicting wall shear stress is a convolutional neural network that uses the informative component of the velocity as input, while the residual velocity component provides no predictive capabilities. Finally, in case (iii), we demonstrate that the informative component of the wall-normal velocity is closely linked to the observability of the target variable and holds the essential information needed to develop successful control strategies.
Twenty-five years ago, the publication of an article by Pallier, Colomé, and Sebastián-Gallés (2001) launched a new and rapidly evolving research program on how second language (L2) learners represent the phonological forms of words in their mental lexicons. Many insights are starting to form an overall picture of the unique difficulties for establishing functional and precise phonolexical representations in L2; however, for the field to move forward it is pertinent to outline its major emerging research questions and existing challenges. Among significant obstacles for further research, the paper explores the current lack of theoretical agreement on the concept of phonolexical representations and the underlying mechanism involved in establishing them, as well as the variable use of the related terminology (e.g., fuzziness and target-likeness). Methodological challenges involved in investigating phonological processing and phonolexical representations as well as their theoretical implications are also discussed. To conclude, we explore the significance of L2-specific phonological representations for the bottom-up lexical access during casual, conversational speech and how our emerging knowledge of L2 lexical representations can be applied in an instructional setting as two potentially fruitful research avenues at the forefront of the current research agenda.
We analyse the motion of a flagellated bacterium in a two-fluid medium using slender body theory. The two-fluid model is useful for describing a body moving through a complex fluid with a microstructure whose length scale is comparable to the characteristic scale of the body. This is true for bacterial motion in biological fluids (entangled polymer solutions), where the entanglement results in a porous microstructure with typical pore diameters comparable to or larger than the flagellar bundle diameter, but smaller than the diameter of the bacterial head. Thus, the polymer and solvent satisfy different boundary conditions on the flagellar bundle and move with different velocities close to it. This gives rise to a screening length $L_B$ within which the fluids exchange momentum and the relative velocity between the two fluids decays. In this work, both the solvent and polymer of the two-fluid medium are modelled as Newtonian fluids with different viscosities $\mu _s$ and $\mu _p$ (viscosity ratio $\lambda = \mu _p/\mu _s$), thereby capturing the effects solely introduced by the microstructure of the complex fluid. From our calculations, we observe an increased drag anisotropy for a rigid, slender flagellar bundle moving through this two-fluid medium, resulting in an enhanced swimming velocity of the organism. The results are sensitive to the interaction between the bundle and the polymer, and we discuss two physical scenarios corresponding to two types of interaction. Our model provides an explanation for the experimentally observed enhancement of swimming velocity of bacteria in entangled polymer solutions and motivates further experimental investigations.
Metastructures composed of a closely spaced plate array have been widely used in bespoke manipulation of waves in contexts of acoustics, electromagnetics, elasticity and water waves. This paper focuses on wave scattering by discrete plate array metastructures of arbitrary cross-sections, including isolated vertical metacylinders, periodic arrays and horizontal surface-piercing metacylinders. A suitable transform-based method has been applied to each problem to reduce the influence of barriers in a two-dimensional problem to a set of points in a one-dimensional wave equation wherein the solution is constructed using a corresponding Green's function. A key difference from the existing work is the use of an exact description of the plate array rather than an effective medium approximation, enabling the exploration of wave frequencies above resonance where homogenisation models fail but where the most intriguing physical findings are unravelled. The new findings are particularly notable for graded plate array metastructures that produce a dense spectrum of resonant frequencies, leading to broadband ‘rainbow reflection’ effects. This study provides new ideas for the design of structures for the bespoke control of waves with the potential for innovative solutions to coastal protection schemes or wave energy converters.
Traditional wisdom dictates that statistical model outputs are estimates, not measurements. Despite this, statistical models are employed as measurement instruments in the social sciences. In this article, I scrutinize the use of a specific model—the logit model—for psychological measurement. Given the adoption of a criterion for measurement that I call comparability, I show that the logit model fails to yield measurements due to properties that follow from its fixed residual variance.
Clinical trials often struggle to recruit enough participants, with only 10% of eligible patients enrolling. This is concerning for conditions like stroke, where timely decision-making is crucial. Frontline clinicians typically screen patients manually, but this approach can be overwhelming and lead to many eligible patients being overlooked.
Methods:
To address the problem of efficient and inclusive screening for trials, we developed a matching algorithm using imaging and clinical variables gathered as part of the AcT trial (NCT03889249) to automatically screen patients by matching these variables with the trials’ inclusion and exclusion criteria using rule-based logic. We then used the algorithm to identify patients who could have been enrolled in six trials: EASI-TOC (NCT04261478), CATIS-ICAD (NCT04142125), CONVINCE (NCT02898610), TEMPO-2 (NCT02398656), ESCAPE-MEVO (NCT05151172), and ENDOLOW (NCT04167527). To evaluate our algorithm, we compared our findings to the number of enrollments achieved without using a matching algorithm. The algorithm’s performance was validated by comparing results with ground truth from a manual review of two clinicians. The algorithm’s ability to reduce screening time was assessed by comparing it with the average time used by study clinicians.
Results:
The algorithm identified more potentially eligible study candidates than the number of participants enrolled. It also showed over 90% sensitivity and specificity for all trials, and reducing screening time by over 100-fold.
Conclusions:
Automated matching algorithms can help clinicians quickly identify eligible patients and reduce resources needed for enrolment. Additionally, the algorithm can be modified for use in other trials and diseases.
The technique of excised embryos was employed to facilitate the propagation of Podophyllum emodi derived from seeds collected at the different elevation zones of Himachal Pradesh, India. Seed germination was low, irrespective of stage of seed development or zone of collection. Germination was improved significantly (89.14%) in the partially mature and mature seeds collected from alpine and temperate zones when excised embryos were cultured on basal B5 medium. Leaf emergence and plant establishment in the field was also significantly higher in the plants raised through this technique, despite hypocotyl dormancy. The technique was successfully employed for the production of plants to be reintroduced in large numbers into their habitat in the Great Himalayan National Park.
Despite the added value of multisystem (relative to traditional single-system) approaches for characterizing biological processes linked to risk for psychopathology (e.g., neuroendocrine stress responsivity; Buss et al., 2019; Quas et al., 2014), no study to date has evaluated whether multisystem processes may serve as viable biological targets of intervention. Utilizing a multiple-levels-of-analysis approach (Cicchetti & Dawson, 2002), this person-centered study examined whether stress-adapted patterns of hypothalamus–pituitary–adrenal (HPA) axis and sympathetic-adrenomedullary (SAM) system co-activation were amenable to change following the Building a Strong Identity and Coping Skills intervention (BaSICS; Wadsworth et al., 2022). Preadolescents exposed to concentrated poverty (n = 112, Mage = 11.78 years, 57.1% female, 54% assigned to intervention; 40% Hispanic, 63% Black, 20% White) completed questionnaires and the Trier Social Stress Test at both pre- and posttest. Multitrajectory modeling of cortisol and alpha-amylase levels identified four pretest and posttest HPA-SAM co-activation profiles. At pretest, youth exhibiting Asymmetric Nos. 1 & 2 HPA-SAM co-activation reported greater maladjustment relative to youth with Symmetric Nos. 1 & 2 co-activation. Youth exhibiting Asymmetric No. 1 co-activation at pretest were more likely to exhibit Symmetric No. 1 co-activation following BaSICS relative to control. Findings highlight the potential of BaSICS to restore neuroendocrine stress response function in impoverished youth, pointing to HPA–SAM co-activation as a potential biological target of preventive intervention in this population.
The 17 Brazilian species of Adesmia DC were analysed, using 20 primers, with regard to their randomly amplified polymorphic DNA (RAPD) patterns. From a total of 357 individuals analysed, the 20 primers produced 2249 fragments with molecular sizes ranging from 200 to 2700 bp, 56% of which were polymorphic. Average intra-population genetic similarity, estimated by Jaccard's coefficient, ranged from 0.35 in A. araujoi to 0.80 in A. punctata. Mean intra-specific genetic similarity varied greatly among species, ranging from 0.19 for A. tristis to 0.89 for A. arillata. Mean genetic similarity among the species, estimated by Dice's coefficient, was 0.56. RAPD markers were efficient at separating all the accessions analysed. The results obtained generally agreed with the partition of genetic variability expected according to the mode of reproduction.
Governance institutions such as the Arctic Council face ongoing (de)legitimation that impacts the broader legitimacy beliefs which enable them to govern effectively. Research has increasingly studied how different actors engage in legitimation and delegitimation that bolster or challenge legitimacy, but there has been limited study of the variation in the (de)legitimation practices of individual states and the reasons for this variation. This article studies variation in discursive (de)legitimation of the Arctic Council by the United States and China. It advances a theoretical argument for how this variation in (de)legitimation is driven by broader political developments. Using content analysis, it maps these two states’ (de)legitimation of the Arctic Council over a 12-year period and examines evidence for this theory. The article finds that both states vary considerably in their (de)legitimation of the Arctic Council over time. Changes in the intensity of their (de)legitimation are found to be linked to political developments including heightened security tensions, positive/negative shifts in environmental politics, and institutional changes. This contributes empirical evidence and new theoretical insights to the body of research about how different actors engage in (de)legitimation of global governance.
Wild species of rice possess tremendous genetic variations and harbour resistance genes for biotic stresses. Bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae (Xoo), is a major disease affecting rice production globally. The current study characterized 116 accessions from 17 species of Oryza for BB disease during three seasons viz., kharif 2020, rabi 2020–21, kharif 2021 using an isolate of Xanthomonas oryzae pv. oryzae (Xoo) strain IX-020. A total of 40 accessions including Oryza rufipogon, O. nivara, O. officinalis and O. australiensis showed consistence resistance to the bacterial blight disease across the seasons. These accessions were further subjected to molecular characterization using 11 Xa genes viz., Xa4, xa5, xa13, Xa21, Xa23, Xa27(t), Xa32(t), Xa33, Xa35(t), Xa38 and xa41 with gene-specific markers to ascertain the novelty. Some key resistance genes such as Xa4, Xa23, Xa27(t), Xa32(t), Xa33, Xa35(t) and xa41 were detected in multiple accessions, with O. rufipogon and O. eichingeri harbouring particularly complex combinations of these genes. Notably, several accessions viz., IC521672 (O. nivara), EC861665 (O. officinalis), EC861677 (O. latifolia), EC861711 (O. punctata) and EC861738 (O. eichingeri) did not show the presence of any known genes indicating the possibility of novel genetic loci conferring BB resistance in these wild species. These promising accessions identified in the study are potential novel sources for bacterial leaf blight resistance in rice and will be useful for the development of durable bacterial blight resistance rice cultivars.
Antidepressants’ effects are established in randomised controlled trials (RCTs), but not in the real world.
Aims
To investigate real-world comparative effects of antidepressants for depression and compare them with RCTs.
Method
We performed a cohort study based on the QResearch database. We included people with a newly recorded diagnosis of depression, exposed to licensed antidepressants in the UK. We assessed all-cause dropouts (acceptability), dropouts for adverse events (tolerability), occurrence of at least one adverse event (safety), and response and remission on the Patient Health Questionnaire (PHQ)-9 (effectiveness) at 2 and 12 months. Logistic regressions were used to compute adjusted-odds ratio (aOR) with 99% CIs, assessing the associations between exposure to each antidepressant against fluoxetine (comparator) and outcomes of interest. We compared estimates from the real world with RCTs using ratio-of-odds ratio (ROR) with 95% CI.
Results
A total of 673 177 depressed people were studied: females 57.1%, mean age 42.8 (s.d. 17.7) years, mean baseline PHQ-9 17.1 (s.d. 5.0) (moderately severe depression). At 2 months, antidepressant acceptability was 61.4%, tolerability 94.4%, safety 54.5%, PHQ-9 decreased to 12.3 (s.d. 6.5). At 12 months, acceptability was 12.3%, tolerability 87.5%, safety 28.8%, PHQ-9 12.9 (s.d. 6.8). In the short and long term, tricyclics, mirtazapine and trazodone were worse than fluoxetine for most outcomes; citalopram had better acceptability than fluoxetine (aOR 0.95; 99% CI 0.92, 0.97), sertraline had lower tolerability (aOR 1.12; 99% CI 1.06, 1.18), and both citalopram and sertraline had lower safety (aOR 1.17 and 1.25, respectively). In the long term, citalopram had better acceptability (aOR 0.78; 99% CI 0.76, 0.81) and effectiveness (aOR 1.12 for both response and remission), but worse tolerability (aOR 1.09; 99% CI 1.06, 1.13) and safety (aOR 1.12; 99% CI 1.08, 1.16). Observational and randomised data were similar for citalopram and sertraline, while there was some difference for drugs less prescribed in the real world.
Conclusions
Antidepressants showed low acceptability, moderate-to-high tolerability and safety, and small-to-moderate effectiveness in the real world. Real-world and RCT estimates showed similar findings only when the analyses were carried out using large datasets; otherwise, the results diverged.
The distribution theory for discrete-time renewal–reward processes with dependent rewards is developed through the derivation of double transforms. By dependent, we mean the more realistic setting in which the reward for an interarrival period is dependent on the duration of the associated interarrival time. The double transforms are the generating functions in time of the time-dependent reward probability-generating functions. Residue and saddlepoint approximations are used to invert such double transforms so that the reward distribution at arbitrary time n can be accurately approximated. In addition, double transforms are developed for the first-passage time distribution that the cumulative reward exceeds a fixed threshold amount. These distributions are accurately approximated by inverting the double transforms using residue and saddlepoint approximation methods. The residue methods also provide asymptotic expansions for moments and allow for the proof of central limit theorems related to these first passage times and reward amounts.
The combined effects of heater position, mean flow parameters and flame models on thermoacoustic instability in a one-dimensional Rijke tube are studied systematically by classic linear stability analysis (LSA) and lattice Boltzmann method (LBM) simulation. In the former, the stability range of the linear flame model under low Mach number assumption is solved analytically, while in the more general case, it is obtained by numerically solving the dispersion relation. Both the linear and nonlinear flame model cases are studied using the LBM with a spectral multiple-relaxation-time collision model and a newly developed heat source term. With the linear flame model, the LBM is in good agreement with LSA in predicting the transition point and growth rates, while with the nonlinear flame model, LBM simulations are consistent with solutions of limit cycle theory in the fully developed state. These results demonstrate the applicability of the LBM in solving complex thermoacoustic problems.