Buckling Cascade of Thin Plates: Forms, Constraints and Similarity

We experimentally study compression of thin plates in rectangular boxes with variable height. A cascade of buckling is generated. It gives rise to a self-similar evolution of elastic reaction of plates with box height which surprisingly exhibits repetitive vanishing and negative stiffness. These features are understood from properties of Euler's equation for elastica

Bayesian analysis of seasonal unit roots and seasonal mean shifts

In this paper we propose a Bayesian analysis of seasonal unit roots in quarterly observed time series. Seasonal unit root processes are useful to describe economic series with changing seasonal fluctuations. A natural alternative model for similar purposes contains deterministic seasonal mean shifts instead of seasonal stochastic trends. This leads to analysing seasonal unit roots in the presence of mean shifts using Bayesian techniques. Our method is illustrated using several simulated and empirical data

Mean shifts, unit roots and forecasting seasonal time series

Examples of descriptive models for changing seasonal patterns in economic time series are autoregressive models with seasonal unit roots or with deterministic seasonal mean shifts. In this paper we show through a forecasting comparison for three macroeconomic time series (for which tests indicate the presence of seasonal unit roots) that allowing for possible seasonal mean shifts can improve forecast performance. Next, by means of simulation we demonstrate the impact of imposing an incorrect model on forecasting. We find that an inappropriate decision can deteriorate forecasting performance dramatically in both directions, and hence we recommend the practitioner to take account of seasonal mean shifts when testing for seasonal unit roots

Boundary Limitation of Wavenumbers in Taylor-Vortex Flow

We report experimental results for a boundary-mediated wavenumber-adjustment mechanism and for a boundary-limited wavenumber-band of Taylor-vortex flow (TVF). The system consists of fluid contained between two concentric cylinders with the inner one rotating at an angular frequency $\Omega$. As observed previously, the Eckhaus instability (a bulk instability) is observed and limits the stable wavenumber band when the system is terminated axially by two rigid, non-rotating plates. The band width is then of order $\epsilon^{1/2}$ at small $\epsilon$ ($\epsilon \equiv \Omega/\Omega_c - 1$) and agrees well with calculations based on the equations of motion over a wide $\epsilon$-range. When the cylinder axis is vertical and the upper liquid surface is free (i.e. an air-liquid interface), vortices can be generated or expelled at the free surface because there the phase of the structure is only weakly pinned. The band of wavenumbers over which Taylor-vortex flow exists is then more narrow than the stable band limited by the Eckhaus instability. At small $\epsilon$ the boundary-mediated band-width is linear in $\epsilon$. These results are qualitatively consistent with theoretical predictions, but to our knowledge a quantitative calculation for TVF with a free surface does not exist.Comment: 8 pages incl. 9 eps figures bitmap version of Fig

Age of second language acquisition affects nonverbal conflict processing in children : an fMRI study

Background: In their daily communication, bilinguals switch between two languages, a process that involves the selection of a target language and minimization of interference from a nontarget language. Previous studies have uncovered the neural structure in bilinguals and the activation patterns associated with performing verbal conflict tasks. One question that remains, however is whether this extra verbal switching affects brain function during nonverbal conflict tasks. Methods: In this study, we have used fMRI to investigate the impact of bilingualism in children performing two nonverbal tasks involving stimulus-stimulus and stimulus-response conflicts. Three groups of 8-11-year-old children - bilinguals from birth (2L1), second language learners (L2L), and a control group of monolinguals (1L1) - were scanned while performing a color Simon and a numerical Stroop task. Reaction times and accuracy were logged. Results: Compared to monolingual controls, bilingual children showed higher behavioral congruency effect of these tasks, which is matched by the recruitment of brain regions that are generally used in general cognitive control, language processing or to solve language conflict situations in bilinguals (caudate nucleus, posterior cingulate gyrus, STG, precuneus). Further, the activation of these areas was found to be higher in 2L1 compared to L2L. Conclusion: The coupling of longer reaction times to the recruitment of extra language-related brain areas supports the hypothesis that when dealing with language conflicts the specialization of bilinguals hampers the way they can process with nonverbal conflicts, at least at early stages in life

The Working Alliance Inventory's Measurement Properties:A Systematic Review

Measurement properties of the Working Alliance Inventory (WAI) and its various translations and adaptations for specific target groups have been investigated for over 30 years. No systematic review analyzing studies on measurement properties of the WAI has been conducted to date. COnsensus-based Standards for the selection of health Measurements INstruments (COSMIN) were developed for conducting high-quality systematic reviews on measurement properties in a transparent and standardized way. Aim of this study was to systematically review studies on measurement properties of the WAI, and its adapted versions, within psychotherapy, and other healthcare contexts using COSMIN criteria. PsycINFO, Medline, and EMBASE were searched (1989-2021). In all phases of the review procedure, study selection, data extraction, risk of bias assessment, rating of the quality of measurement properties, and rating of the quality of evidence for measurement properties, disagreement between reviewers was resolved by discussion. Results on validity, internal structure, reliability, construct validity, and responsiveness were analyzed. In total 66 studies were included. In most studies, evidence for measurement properties was according to COSMIN criteria, insufficient, lacking, or conflicting. Content validity was rated insufficient because neither patients nor healthcare professionals were involved in the development and validation process. Hence evidence for content validity of the WAI is unknown. Conflicting evidence was found for structural validity. Evidence for internal consistency could not be established. Limited evidence was found for inter-rater reliability and convergent validity. Conflicting evidence was also found for test-retest reliability and divergent validity. COSMIN criteria exposed persistent problems in validation studies of the WAI. These findings may indicate that measurement properties of the WAI are not up to current standards, or that COSMIN criteria may be less appropriate for assessing measurement properties of the WAI, or it could indicate both. The results of this systematic review suggest that WAI outcomes should be interpreted with caution and further research is needed regarding the content validity and hypotheses development. For the future, the theoretical framework underlying the measurement of the working alliance needs to be studied in psychotherapy and other health contexts, and tested in methodologically sound studies

Participants' unspoken thoughts and feelings negatively influence the therapeutic alliance; a qualitative study in a multidisciplinary pain rehabilitation setting

PURPOSE: This study aimed to explore factors that influence participants' perceptions of the therapeutic alliance with healthcare professionals; their participation in the alliance; and their commitment to treatment in a multidisciplinary pain rehabilitation setting. MATERIALS AND METHODS: A qualitative research-design was used and 26 participants in a multidisciplinary pain rehabilitation program were interviewed in-depth. RESULTS: Initially, participants reported to be satisfied with their healthcare professionals. After deeper reflection on the therapeutic alliance, several unspoken thoughts and feelings and relational ruptures emerged. Almost all participants mentioned a history of disappointing and fragmented healthcare, and they reported on how this affected their cognitions, perceptions, and beliefs about the current program. Participants felt insufficiently empowered to voice their concerns and regularly chose to avoid confrontation by not discussing their feelings. They felt a lack of ownership of their problems and did not experience the program as person-centered. CONCLUSIONS: Several factors were found that negatively influence the quality of therapeutic alliance (agreement on bond) and efficacy of the treatment plan (agreement on goals and tasks). To improve outcomes of pain rehabilitation, healthcare professionals should systematically take into account the perceptions and needs of participants, and focus more on personalized collaboration throughout the program offered.Implications for rehabilitationDifferences in perceptions and experiences of pain, together with differences in beliefs about the causes of pain, negatively influence the therapeutic alliance.When participants and healthcare professionals operate from different paradigms, it is important that they negotiate these differences.From the perspective of participants, a clear-cut organization of healthcare that encourages collaboration is required.It is important to focus on personalized collaboration from the start and during treatment, and to recognize and discuss disagreement on diagnosis and treatment plans.During this collaboration, healthcare professionals should systematically take into account the perceptions and needs of the participants

Effect of age and sex on immune checkpoint expression and kinetics in human T cells

BACKGROUND: Immune checkpoints are crucial molecules in maintaining a proper immune balance. Even though age and sex are known to have effects on the immune system, the interplay between age, sex and immune checkpoint expression by T cells is not known. The aim of this study was to determine whether age and sex affect immune checkpoint expression by T cells and if age and sex affect the kinetics of immune checkpoint expression following ex vivo stimulation. In this study, whole blood samples of 20 healthy young adults (YA, 9 males and 11 females) and 20 healthy older adults (OA, 9 males and 11 females) were stained for lymphocyte lineage markers and immune checkpoints and frequencies of CD28+, PD-1+, VISTA+ and CD40L+ T cells were determined. Immune checkpoint expression kinetics were studied following ex vivo anti-CD3/anti-CD28 stimulation of T cells from young and older healthy adults. RESULTS: We report an age-associated increase of CD40L + CD4+ and CD40L + CD8+ T-cell frequencies, whereas CD40+ B-cell frequencies were decreased in older adults, suggesting modulation of the CD40L-CD40 interaction with age. Immune checkpoint expression kinetics revealed differences in magnitude between CD4+ and CD8+ T cells independent of age and sex. Further analysis of CD4+ T-cell subsets revealed an age-associated decrease of especially PD-1 + CD4+ memory T cells which tracked with the female sex. CONCLUSION: Collectively, our results demonstrate that both age and sex modulate expression of immune checkpoints by human T cells. These findings may have implications for optimising vaccination and immune checkpoint immunotherapy and move the field towards precision medicine in the management of older patient groups

Rotating Convection in an Anisotropic System

We study the stability of patterns arising in rotating convection in weakly anisotropic systems using a modified Swift-Hohenberg equation. The anisotropy, either an endogenous characteristic of the system or induced by external forcing, can stabilize periodic rolls in the K\"uppers-Lortz chaotic regime. For the particular case of rotating convection with time-modulated rotation where recently, in experiment, chiral patterns have been observed in otherwise K\"uppers-Lortz-unstable regimes, we show how the underlying base-flow breaks the isotropy, thereby affecting the linear growth-rate of convection rolls in such a way as to stabilize spirals and targets. Throughout we compare analytical results to numerical simulations of the Swift-Hohenberg equation

Seasonality and stochastic trends in German consumption and income, 1960.1- 1987.4

The quarterly time series of German consumption and income are analyzed with respect to seasonality and stochastic trends. It emerges that both variables can be appropriately described by a periodically integrated autoregression. An implication is that the stochastic trend and the seasonal fluctuations are not independent for each of the univariate series. In order to test for cointegration across the two series, we propose several methods which take account of the relationship between seasons and trends in the univariate series. Some of these methods boil down to extracting the stochastic trend from the univariate series in a first step and to relating these trends using cointegration techniques in a second step. Another method is an extension of the Johansen cointegration testing approach to periodic vector autoregressions. Monte Carlo simulations are used to evaluate the empirical performance of the various methods. The main empirical result is that only in the first quarter there seems to be cointegration between German consumption and income