893 research outputs found

    Coexistence of antiferrodistortive and ferroelectric distortions at the PbTiO3_3 (001) surface

    Full text link
    The c(2×\times2) reconstruction of (001) PbTiO3_3 surfaces is studied by means of first principles calculations for paraelectric (non-polar) and ferroelectric ([001] polarized) films. Analysis of the atomic displacements in the near-surface region shows how the surface modifies the antiferrodistortive (AFD) instability and its interaction with ferroelectric (FE) distortions. The effect of the surface is found to be termination dependent. The AFD instability is suppressed at the TiO2_2 termination while it is strongly enhanced, relative to the bulk, at the PbO termination resulting in a c(2x2) surface reconstruction which is in excellent agreement with experiments. We find that, in contrast to bulk PbTiO3_3, in-plane ferroelectricity at the PbO termination does not suppress the AFD instability. The AFD and the in-plane FE distortions are instead concurrently enhanced at the PbO termination. This leads to a novel surface phase with coexisting FE and AFD distortions which is not found in PbTiO3_3 bulk

    Building Collaborative Partnerships to Increase Postsecondary Education Opportunities for Students with Intellectual and Developmental Disabilities

    Get PDF
    Transitioning from high school to the next phase of life can be especially challenging for youth with intellectual and other developmental disabilities (IDD). Federal mandates are in place to provide individualized transition services to students with disabilities up to age 22; however, there is variability in the location of service delivery. A growing number of school districts have partnered with institutions of higher education (IHE) in an effort to enhance postsecondary education (PSE) opportunities for individuals with IDD who are between the ages of 18-21. While there are some differences in PSE programs, the core foundational component is constant across models: establishing and maintaining collaborative partnerships between school districts and IHE. This paper describes PSE program models and highlights the necessity to continue to build partnerships in an effort to expand PSE opportunities for young adults with IDD

    Genetical Genomics Reveals Large Scale Genotype-By-Environment Interactions in Arabidopsis thaliana

    Get PDF
    One of the major goals of quantitative genetics is to unravel the complex interactions between molecular genetic factors and the environment. The effects of these genotype-by-environment interactions also affect and cause variation in gene expression. The regulatory loci responsible for this variation can be found by genetical genomics that involves the mapping of quantitative trait loci (QTLs) for gene expression traits also called expression-QTL (eQTLs). Most genetical genomics experiments published so far, are performed in a single environment and hence do not allow investigation of the role of genotype-by-environment interactions. Furthermore, most studies have been done in a steady state environment leading to acclimated expression patterns. However a response to the environment or change therein can be highly plastic and possibly lead to more and larger differences between genotypes. Here we present a genetical genomics study on 120 Arabidopsis thaliana, Landsberg erecta × Cape Verde Islands, recombinant inbred lines (RILs) in active response to the environment by treating them with 3 h of shade. The results of this experiment are compared to a previous study on seedlings of the same RILs from a steady state environment. The combination of two highly different conditions but exactly the same RILs with a fixed genetic variation showed the large role of genotype-by-environment interactions on gene expression levels. We found environment-dependent hotspots of transcript regulation. The major hotspot was confirmed by the expression profile of a near isogenic line. Our combined analysis leads us to propose CSN5A, a COP9 signalosome component, as a candidate regulator for the gene expression response to shade

    A recalibrated prediction model can identify level-1 trauma patients at risk of nosocomial pneumonia

    Get PDF
    Introduction: Nosocomial pneumonia has poor prognosis in hospitalized trauma patients. Croce et al. published a model to predict post-traumatic ventilator-associated pneumonia, which achieved high discrimination and reasonable sensitivity. We aimed to externally validate Croce’s model to predict nosocomial pneumonia in patients admitted to a Dutch level-1 trauma center. Materials and methods: This retrospective study included all trauma patients (≥ 16y) admitted for &gt; 24 h to our level-1 trauma center in 2017. Exclusion criteria were pneumonia or antibiotic treatment upon hospital admission, treatment elsewhere &gt; 24 h, or death &lt; 48 h. Croce’s model used eight clinical variables—on trauma severity and treatment, available in the emergency department—to predict nosocomial pneumonia risk. The model’s predictive performance was assessed through discrimination and calibration before and after re-estimating the model’s coefficients. In sensitivity analysis, the model was updated using Ridge regression. Results: 809 Patients were included (median age 51y, 67% male, 97% blunt trauma), of whom 86 (11%) developed nosocomial pneumonia. Pneumonia patients were older, more severely injured, and underwent more emergent interventions. Croce’s model showed good discrimination (AUC 0.83, 95% CI 0.79–0.87), yet predicted probabilities were too low (mean predicted risk 6.4%), and calibration was suboptimal (calibration slope 0.63). After full model recalibration, discrimination (AUC 0.84, 95% CI 0.80–0.88) and calibration improved. Adding age to the model increased the AUC to 0.87 (95% CI 0.84–0.91). Prediction parameters were similar after the models were updated using Ridge regression. Conclusion: The externally validated and intercept-recalibrated models show good discrimination and have the potential to predict nosocomial pneumonia. At this time, clinicians could apply these models to identify high-risk patients, increase patient monitoring, and initiate preventative measures. Recalibration of Croce’s model improved the predictive performance (discrimination and calibration). The recalibrated model provides a further basis for nosocomial pneumonia prediction in level-1 trauma patients. Several models are accessible via an online tool. Level of evidence: Level III, Prognostic/Epidemiological Study.</p

    Progenitor cell niche senescence reflects pathology of the parotid salivary gland in primary Sjogren's syndrome

    Get PDF
    Objective. Salivary gland (SG) progenitor cells (SGPCs) maintain SG homeostasis. We have previously shown that in primary Sjogren's syndrome (pSS), SGPCs are likely to be senescent, and may underpin SG dysfunction. This study assessed the extent of senescence of cells in a SGPC niche in pSS patients' SGs, and its correlation with functional and clinical parameters. Methods. The expression of p16 and p21 as markers of senescence in both total SG epithelium and a SGPC niche (basal striated duct cells, BSD) was examined in SGs of pSS (n = 35) , incomplete pSS (n = 1 3) (patients with some signs of pSS, but not fulfilling all classification criteria) and non-SS sicca control (n = 21) patients. This was correlated with functional and clinical parameters. Results. pSS patient SGs contained significantly more p16(+) cells both in the epithelium in general (P Conclusion. These findings suggest SGPC senescence may be an early feature of primary Sjogren's syndrome and may contribute to defective SG function in pSS but not to systemic disease activity

    Near‐millimeter‐wave response of high Tc ramp‐type Josephson junctions

    Get PDF
    We have studied the response of a YBCO/PBCO/YBCO ramp‐type junction to coherent radiation at 176 and 270 GHz. The I‐V characteristic of the junction closely resembles the prediction of the RSJ model. The I cR n product of the junction is 0.25 mV at 5 K. The millimeter‐wave radiation is coupled to the junction via a quasioptical structure that focuses the radiation onto the junction through a yttrium‐stabilized ZrO2 substrate. At 176 GHz, we have observed as many as six Shapiro steps at the maximum power level of our Gunn oscillator‐pumped frequency doubler. Shapiro steps are still clearly seen up to 65 K. The amplitudes of the zeroth, first, and second Shapiro steps, as functions of the square root of the radiation power, agree remarkably well with a Bessel function fit, indicating the junction is voltage‐biased at the radiation frequency (rf). At 270 GHz, due to a combination of the heavy rf loss in the ZrO2 substrate and the lack of radiation power, we have observed only the first Shapiro step

    Explanations for medically unexplained symptoms:a qualitative study on GPs in daily practice consultations

    Get PDF
    BACKGROUND: General practice is the centre of care for patients with medically unexplained symptoms (MUS). Providing explanations for MUS, i.e. making sense of symptoms, is considered to be an important part of care for MUS patients. However, little is known how general practitioners (GPs) do this in daily practice. OBJECTIVE: This study aimed to explore how GPs explain MUS to their patients during daily general practice consultations. METHODS: A thematic content analysis was performed of how GPs explained MUS to their patients based on 39 general practice consultations involving patients with MUS. RESULTS: GP provided explanations in nearly all consultations with MUS patients. Seven categories of explanation components emerged from the data: defining symptoms, stating causality, mentioning contributing factors, describing mechanisms, excluding explanations, discussing the severity of symptoms and normalizing symptoms. No pattern of how GPs constructed explanations with the various categories was observed. In general, explanations were communicated as a possibility and in a patient-specific way; however, they were not very detailed. CONCLUSION: Although explanations for MUS are provided in most MUS consultations, there seems room for improving the explanations given in these consultations. Further studies on the effectiveness of explanations and on the interaction between patients and GP in constructing these explanations are required in order to make MUS explanations more suitable in daily primary care practice

    Lactate turnover in rat glioma measured by in vivo nuclear magnetic resonance spectroscopy

    Get PDF
    Elevated tissue lactate concentrations typically found in tumors can be measured by in vivo nuclear magnetic resonance (NMR) spectroscopy. In this study, lactate turnover in rat C6 glioma was determined from in vivo 1H NMR measurements of [3-13C]lactate buildup during steady-state hyperglycemia with [1-13C]glucose. With this tumor model, a narrow range of values was observed for the first-order rate constant that describes lactate efflux, k2 = 0.043 ± 0.007 (n = 12) SD min-1. For individual animals, the standard error in k2 was small (<18%), which indicated that the NMR data fit the kinetic model well. Lactate measurements before and after infusing [1- 13C]glucose showed that the majority of the tumor lactate pool was metabolically active. Signals from 13C-labeled glutamate in tumors were at least 10-fold smaller than the [3-13C]lactate signal, whereas spectra of the contralateral hemispheres revealed the expected labeling of [4- 13C]glutamate, as well as [2-13C] and [3-13C]glutamate, which indicates that label cycled through the tricarboxylic acid cycle in the brain tissue. Lack of significant 13C labeling of glutamate was consistent with low respiratory metabolism in this glioma. It is concluded that lactate in rat C6 glioma is actively turning over and that the kinetics of lactate efflux can be quantified noninvasively by 1H NMR detection of 13C label. This noninvasive NMR approach may offer a valuable tool to help evaluate tumor growth and metabolic responsiveness to therapies

    Mind the implementation gap?:Police reform and local policing in the Netherlands and Scotland

    Get PDF
    In 2013 the governments of the Netherlands and Scotland established national police forces, replacing a tradition of largely autonomous regional police organizations. In both jurisdictions, these radical reforms have raised concerns about the consequences of these national police structures for local policing and for relationships with local communities and local government. Drawing on documentary sources and interview material from each jurisdiction and informed by insights from the policy implementation literature, the key question addressed in this article is how has the legislation that created the new national police forces been put into effect at a local level? Focusing on the impact on the governance, organization and delivery of local policing, the article reveals how the implementation in both jurisdictions involves interpretation and discretion by multiple actors so that gaps are emerging between the national ‘policy promises’ set out in the legislation and the ‘policy products’ experienced in local contexts
    corecore