Abstract
We study the perspectives of measuring the phenomenon of vacuum birefringence predicted by quantum electrodynamics using an x-ray free-electron laser (XFEL) alone. We devise an experimental ...scheme allowing two consecutive XFEL pulses to collide under a finite angle, and thus act as both pump and probe field for the effect. The signature of vacuum birefringence is encoded in polarization-flipped signal photons to be detected with high-purity x-ray polarimetry. Our findings for idealized scenarios underline that the discovery potential of solely XFEL-based setups can be comparable to those involving optical high-intensity lasers. For currently achievable scenarios, we identify several key details of the x-ray optical ingredients that exert a strong influence on the magnitude of the desired signatures.
Abstract
Identification of active electrocatalysts for the oxygen evolution reaction (OER), corresponding to the bottleneck in electrolyzers to produce gaseous hydrogen as energy vector, by ...electronic structure calculations relies on the assumption of the mononuclear mechanism, comprising the *OH, *O, and *OOH intermediates. This mechanistic description is thermodynamically hampered by a scaling relation between the *OH and *OOH adsorbates, which may serve as an explanation why OER catalysts commonly require large overpotentials to reach sufficient current densities. Recently, an alternate OER pathway was proposed that, in contrast to the mononuclear description, consists of the formation of two adjacent *OO adsorbates, and gaseous oxygen is produced by chemical recombination of the neighboring *OO intermediates. In the present manuscript, a data-driven model based on a dedicated assessment of the elementary reaction steps is deduced, which enables evaluating the mononuclear and *OO pathways by the same set of parameters. Potential-dependent volcano plots are constructed to comprehend the energetics of the competing mechanisms. It is demonstrated that the alternate OER pathway consisting of the *OO∙∙*OO recombination step may excel the mononuclear description at overpotentials corresponding to typical OER conditions. Consequently, it is suggested that future studies, aiming at the identification of OER materials, may not omit the *OO∙∙*OO recombination mechanism when using concepts of materials screening in a heuristic fashion or multiscale modeling.
Additive manufacturing allows for the production of complex components using various types of materials such as plastics, metals and ceramics without the need for molding tools. In the field of ...high-performance polymers, semi-crystalline polymers such as polyetheretherketone (PEEK) or amorphous polymers such as polyetherimide (PEI) are already successfully applied. Contrary to semi-crystalline and amorphous polymers, thermotropic liquid crystalline polymers (LCPs) do not change into an isotropic liquid during melting. Instead, they possess anisotropic properties in their liquid phase. Within the scope of this work, this special group of polymers was investigated with regard to its suitability for processing by means of fused filament fabrication. Using an LCP with a low melting temperature of around 280 °C is compared to processing an LCP that exhibits a high melting temperature around 330 °C. In doing so, it was revealed that the achievable mechanical properties strongly depend on the process parameters such as the direction of deposition, printing temperature, printing speed and layer height. At a layer height of 0.10 mm, a Young's modulus of 27.3 GPa was achieved. Moreover, by employing an annealing step after the printing process, the tensile strength could be increased up to 406 MPa at a layer height of 0.15 mm. Regarding the general suitability for FFF as well as the achieved uniaxial mechanical properties, the LCP with a low melting temperature was advantageous compared to the LCP with a high melting temperature.
Background
Parental involvement in homework is a home‐based type of involvement in children's education. Research and theory suggest that it is beneficial for learning and achievement under certain ...conditions and for particular groups of individuals.
Aims
The study examined whether different types of parents' involvement in homework (autonomy support, control, interference, cognitive engagement) (1) are predicted by their mastery and performance goals for their child and their beliefs of the child's academic efficacy, and (2) predict student achievement goal orientations, efficacy beliefs, and achievement. Grade‐level differences were also investigated.
Sample
The sample consisted of 282 elementary school (5th grade) and junior high school students (8th grade) and one of their parents.
Methods
Surveys were used for data collection. Structural equation modelling was applied for data analysis.
Results
(1) Autonomy support during homework was predicted by parent mastery goal, parents' control and interference by their performance goal and perceptions of child efficacy, and cognitive engagement as supplementary to homework by parent perceptions of child efficacy. (2) Parental autonomy support, control, and interference were differentially associated with student mastery and performance goal orientations, whereas parent cognitive engagement was associated with student efficacy beliefs. (3) The structural model was the same for elementary and junior high school students but the latent means for a number of variables were different.
Conclusion
Different types of parental involvement in homework were associated with different outcomes with parent autonomy support to be the most beneficial one.
The main roles of fault detection and diagnosis (FDD) for industrial processes are to make an effective indicator which can identify faulty status of a process and then to take a proper action ...against a future failure or unfavorable accidents. In order to enhance many process performances (e.g., quality and throughput), FDD has attracted great attention from various industrial sectors. Many traditional FDD techniques have been developed for checking the existence of a trend or pattern in the process or whether a certain process variable behaves normally or not. However, they might fail to produce several hidden characteristics of the process or fail to discover the faults in processes due to underlying process dynamics. In this paper, we present current research and developments of FDD approaches for process monitoring as well as a broad literature review of many useful FDD approaches.
The threshold of intraoperative urine output below which the risk of acute kidney injury (AKI) increases is unclear. The aim of this retrospective cohort study was to investigate the relationship ...between intraoperative urine output during major abdominal surgery and the development of postoperative AKI and to identify an optimal threshold for predicting the differential risk of AKI.
Perioperative data were collected retrospectively on 3560 patients undergoing major abdominal surgery (liver, colorectal, gastric, pancreatic, or oesophageal resection) at Kyoto University Hospital. We evaluated the relationship between intraoperative urine output and the development of postoperative AKI as defined by recent guidelines. Logistic regression analysis was performed to adjust for patient and operative variables, and the minimum P-value approach was used to determine the threshold of intraoperative urine output that independently altered the risk of AKI.
The overall incidence of AKI in the study population was 6.3%. Using the minimum P-value approach, a threshold of 0.3 ml kg−1 h−1 was identified, below which there was an increased risk of AKI (adjusted odds ratio, 2.65; 95% confidence interval, 1.77–3.97; P<0.001). The addition of oliguria <0.3 ml kg−1 h−1 to a model with conventional risk factors significantly improved risk stratification for AKI (net reclassification improvement, 0.159; 95% confidence interval, 0.049–0.270; P=0.005).
Among patients undergoing major abdominal surgery, intraoperative oliguria <0.3 ml kg−1 h−1 was significantly associated with increased risk of postoperative AKI.
Atomic-scale insights into the performance of electrode materials in lithium-ion batteries require thermodynamic considerations as first step in order to determine potential surface structures that ...are relevant for subsequent kinetic studies. Within the last 20 years, research in heterogeneous catalysis as well as in electrocatalysis has been spurred by the ab initio atomistic thermodynamics approach, whose application for electrode materials in lithium-ion batteries is eyed and discussed in this perspective article.
Employing the diagonal BEKK model as well as the dynamic impulse response functions, this study investigates the time-varying trilateral relationships among real oil prices, exchange rate changes, ...and stock market returns in China and the U.S. from February 1991 to December 2015. We highlight several key observations: (i) oil prices respond positively and significantly to aggregate demand shocks; (ii) positive oil supply shocks adversely and significantly affect the Chinese stock market; (iii) oil price shocks persistently and significantly impact the trade-weighted US dollar index negatively; (iv) the US and China stock markets correlate positively just as the dollar index and the exchange rate does; (v) a significant parallel inverse relation exists between the US stock market and the dollar and between the China stock market and the exchange rate; and (vi) the Chinese stock market is more volatile and responsive to aggregate demand and oil price shocks than the US stock market in recent years.
Wafer map defect classification plays a crucial role in sustaining the semiconductor supply chain during industrial disruptions by ensuring continuity, resilience, and efficiency while aligning with ...sustainability principles. Up to 30 percent of production costs is lost to chip testing and yield losses for semiconductor manufacturing supply chain. In the semiconductor practice, wafer map defects recognition plays a linchpin role in the front-end-of-line stage. Defect pattern recognition can directly pinpoint the assignable causes and provide the domain experts with actionable insights. However, various wafer defect types occur differently from each other, which makes the collected wafer map dataset to be highly imbalanced in defect classes. In the face of data imbalance, the classification model usually cannot provide satisfactory classification performance. In this aspect, this paper intends to investigate the wafer defect map classification problem by using Vision Transformer (ViT) as an alternative data augmentation approach. The primary purpose is to alleviate the class-imbalance issue and then the performance of a deep learning-based convolutional neural network for wafer defect classification can be effectively improved. The experimental results demonstrate that the proposed data augmentation method by using ViT proves to be a potential generative model for improving wafer map defect classification, particularly robust on the individual minority class. In a word, the proposed augmentation framework for wafer map defect classification facilitates a more targeted and efficient approach to quality control, resource utilization, and production optimization in maintaining a sustainable semiconductor supply chain, particularly in times of industrial disruption.
The mitochondrial outer membrane (MOM) harbors proteins that traverse the membrane via several helical segments and are called multi-span proteins. To obtain new insights into the biogenesis of these ...proteins, we utilized yeast mitochondria and the multi-span protein Om14. Testing different truncation variants, we show that while only the full-length protein contains all the information that assures perfect targeting specificity, shorter variants are targeted to mitochondria with compromised fidelity. Employing a specific insertion assay and various deletion strains, we show that proteins exposed to the cytosol do not contribute significantly to the biogenesis process. We further demonstrate that Mim1 and Porin support optimal membrane integration of Om14 but none of them are absolutely required. Unfolding of newly synthesized Om14, its optimal hydrophobicity, and higher fluidity of the membrane enhanced the import capacity of Om14. Collectively, these findings suggest that MOM multi-span proteins follow different biogenesis pathways in which proteinaceous elements and membrane behavior contribute to a variable extent to the combined efficiency.
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