Quantum field theory predicts a nonlinear response of the vacuum to strong electromagnetic fields of macroscopic extent. This fundamental tenet has remained experimentally challenging and is yet to be tested in the laboratory. A particularly distinct signature of the resulting optical activity of the quantum vacuum is vacuum birefringence. This offers an excellent opportunity for a precision test of nonlinear quantum electrodynamics in an uncharted parameter regime. Recently, the operation of the high-intensity Relativistic Laser at the X-ray Free Electron Laser provided by the Helmholtz International Beamline for Extreme Fields has been inaugurated at the High Energy Density scientific instrument of the European X-ray Free Electron Laser. We make the case that this worldwide unique combination of an X-ray free-electron laser and an ultra-intense near-infrared laser together with recent advances in high-precision X-ray polarimetry, refinements of prospective discovery scenarios and progress in their accurate theoretical modelling have set the stage for performing an actual discovery experiment of quantum vacuum nonlinearity.

In this paper, we investigate the attitude manoeuver planning and tracking control of the flexible satellite equipped with a coilable mast. Due to its flexible beamlike structure, the coilable mast experiences bending and torsional modal vibrations in multi-direction. The complex nonlinear coupling and other external disturbances significantly impact the achievement of high-precision attitude control. To overcome these challenges, a robust attitude tracking controller is proposed for easy implementation by the Attitude Determination and Control System (ADCS). The controller consists of a disturbance compensator, feedforward controller and output feedback controller. The compensator, based on a Nonlinear Disturbance Observer (NDO), effectively compensates for the cluster disturbances caused by vibrations, environmental factors and parameter perturbations. The feedforward controller tracks the desired path in the nominal satellite model. Furthermore, the output feedback controller enables large-angle manoeuver control of the satellite and evaluates the suppression effect of the controlled output on the observation error of cluster disturbances used the ${L_2}$-gain. Simulation results demonstrate that the proposed controller successfully achieves high-precision attitude tracking control during large-angle manoeuvering.

Previously published guidelines have provided comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format designed to assist acute-care hospitals in implementing and prioritizing efforts to prevent methicillin-resistant Staphylococcus aureus (MRSA) transmission and infection. This document updates the “Strategies to Prevent Methicillin-Resistant Staphylococcus aureus Transmission and Infection in Acute Care Hospitals” published in 2014.1 This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA). It is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the Association for Professionals in Infection Control and Epidemiology (APIC), the American Hospital Association (AHA), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise.

As an effective drag reduction and thermal protection technology, the opposing jet can guarantee the flight safety of the hypersonic vehicle. In this paper, the jet mode transition is realised by controlling the total jet pressure ratio value (PR) with a function. The jet mode transition from the long penetration mode (LPM) to the short penetration mode (SPM) uses an increasing function. However, the jet mode transition from SPM to LPM uses a decreasing function. The flow field reconstruction process of a two-dimensional axisymmetric blunt body model in the hypersonic flow is studied when the jet mode transition between SPM and LPM changes into each other. The flow field structures and wall parameters of the LPM and SPM transition processes are obtained. The results indicate that the drag and Stanton number both decrease in the transition stage from LPM to SPM, and this is beneficial for the improvement of the drag reduction and thermal protection effect. The peak values of drag and Stanton number fall by 36.39% and 46.40%, respectively. When the jet mode transforms from SPM to LPM, the Stanton number increases, and the drag force first increases and then decreases. However, the final drag reduction effect is not obvious. With the increase in the change rate of the total pressure ratio of the two jet transformation modes, the jet mode transition time is advanced, and the flow field changes more violently.

Background: Saccade and pupil responses are potential neurodegenerative disease biomarkers due to overlap between oculomotor circuitry and disease-affected areas. Instruction-based tasks have previously been examined as biomarker sources, but are arduous for patients with limited cognitive abilities; additionally, few studies have evaluated multiple neurodegenerative pathologies concurrently. Methods: The Ontario Neurodegenerative Disease Research Initiative recruited individuals with Alzheimer’s disease (AD), mild cognitive impairment (MCI), amyotrophic lateral sclerosis (ALS), frontotemporal dementia, progressive supranuclear palsy, or Parkinson’s disease (PD). Patients (n=274, age 40-86) and healthy controls (n=101, age 55-86) viewed 10 minutes of frequently changing video clips without instruction while their eyes were tracked. We evaluated differences in saccade and pupil parameters (e.g. saccade frequency and amplitude, pupil size, responses to clip changes) between groups. Results: Preliminary data indicates low-level behavioural alterations in multiple disease cohorts: increased centre bias, lower overall saccade rate and reduced saccade amplitude. After clip changes, patient groups generally demonstrated lower saccade rate but higher microsaccade rate following clip change to varying degrees. Additionally, pupil responses were blunted (AD, MCI, ALS) or exaggerated (PD). Conclusions: This task may generate behavioural biomarkers even in cognitively impaired populations. Future work should explore the possible effects of factors such as medication and disease stage.

OBJECTIVES/GOALS: Surgical training is constrained by duty hour limits, bias, and a trial-and-error learning process. Surgeon skill variation is a healthcare system disparity that can impact patient outcomes. Incorporating validated, standardized assessment tools and machine learning (ML) algorithms may help to standardize and reduce bias in surgeon education. METHODS/STUDY POPULATION: To support assessment tool and ML algorithm development, we are curating an annotated video registry of neurosurgical procedures. Point-of-view video of resident and attending neurosurgeons performing craniotomies is recorded via an eye-tracking headset. A Delphi panel of neurosurgeons will review the video and determine which represent expert versus trainee performance. Neurosurgery attendings will be interviewed to provide descriptions of craniotomies which will be used to develop an assessment rubric. A Delphi panel will determine what rubric components should be maintained. New craniotomy videos will be viewed by attendings in a blinded fashion while completing the assessment rubric. An online feedback platform is being developed allowing residents to prospectively track assessment data. RESULTS/ANTICIPATED RESULTS: We anticipate development of an annotated, institutional video database featuring craniotomies performed by residents and attending neurosurgeons. Using a Delphi approach, we anticipate achieving consensus on which videos reflect expert versus trainee performance. We anticipate development of a novel craniotomy assessment rubric that is both valid and reliable. Our online feedback platform will allow prospective tracking of assessment data from multiple sources and enhanced transparency in the feedback process. The video registry and assessment data will enable development of novel ML algorithms able to recognize craniotomy segments and estimate operator skill. DISCUSSION/SIGNIFICANCE: Building a video registry of procedures, validated assessment tools, and a prototype feedback platform enables a pipeline for ML algorithm development. Together these tools will help to standardize and optimize resident education translating to earlier operative independence, improved patient safety, and reduced bias during surgical training.

As a typical plasma-based optical element that can sustain ultra-high light intensity, plasma density gratings driven by intense laser pulses have been extensively studied for wide applications. Here, we show that the plasma density grating driven by two intersecting driver laser pulses is not only nonuniform in space but also varies over time. Consequently, the probe laser pulse that passes through such a dynamic plasma density grating will be depolarized, that is, its polarization becomes spatially and temporally variable. More importantly, the laser depolarization may spontaneously take place for crossed laser beams if their polarization angles are arranged properly. The laser depolarization by a dynamic plasma density grating may find application in mitigating parametric instabilities in laser-driven inertial confinement fusion.

The great demographic pressure brings tremendous volume of beef demand. The key to solve this problem is the growth and development of Chinese cattle. In order to find molecular markers conducive to the growth and development of Chinese cattle, sequencing was used to determine the position of copy number variations (CNVs), bioinformatics analysis was used to predict the function of ZNF146 gene, real-time fluorescent quantitative polymerase chain reaction (qPCR) was used for CNV genotyping and one-way analysis of variance was used for association analysis. The results showed that there exists CNV in Chr 18: 47225201-47229600 (5.0.1 version) of ZNF146 gene through the early sequencing results in the laboratory and predicted ZNF146 gene was expressed in liver, skeletal muscle and breast cells, and was amplified or overexpressed in pancreatic cancer, which promoted the development of tumour through bioinformatics. Therefore, it is predicted that ZNF146 gene affects the proliferation of muscle cells, and then affects the growth and development of cattle. Furthermore, CNV genotyping of ZNF146 gene was three types (deletion type, normal type and duplication type) by Real-time fluorescent quantitative PCR (qPCR). The association analysis results showed that ZNF146-CNV was significantly correlated with rump length of Qinchuan cattle, hucklebone width of Jiaxian red cattle and heart girth of Yunling cattle. From the above results, ZNF146-CNV had a significant effect on growth traits, which provided an important candidate molecular marker for growth and development of Chinese cattle.

Background: Eye movements reveal neurodegenerative disease processes due to overlap between oculomotor circuitry and disease-affected areas. Characterizing oculomotor behaviour in context of cognitive function may enhance disease diagnosis and monitoring. We therefore aimed to quantify cognitive impairment in neurodegenerative disease using saccade behaviour and neuropsychology. Methods: The Ontario Neurodegenerative Disease Research Initiative recruited individuals with neurodegenerative disease: one of Alzheimer’s disease, mild cognitive impairment, amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson’s disease, or cerebrovascular disease. Patients (n=450, age 40-87) and healthy controls (n=149, age 42-87) completed a randomly interleaved pro- and anti-saccade task (IPAST) while their eyes were tracked. We explored the relationships of saccade parameters (e.g. task errors, reaction times) to one another and to cognitive domain-specific neuropsychological test scores (e.g. executive function, memory). Results: Task performance worsened with cognitive impairment across multiple diseases. Subsets of saccade parameters were interrelated and also differentially related to neuropsychology-based cognitive domain scores (e.g. antisaccade errors and reaction time associated with executive function). Conclusions: IPAST detects global cognitive impairment across neurodegenerative diseases. Subsets of parameters associate with one another, suggesting disparate underlying circuitry, and with different cognitive domains. This may have implications for use of IPAST as a cognitive screening tool in neurodegenerative disease.

The extent of the reduction of maize (Zea mays L.) kernel moisture content through drying is closely related to field temperature (or accumulated temperature; AT) following maturation. In 2017 and 2018, we selected eight maize hybrids that are widely planted in Northeastern China to construct kernel drying prediction models for each hybrid based on kernel drying dynamics. In the traditional harvest scenario using the optimal sowing date (OSD), maize kernels underwent drying from 4th September to 5th October, with variation coefficients of 1.0–1.9. However, with a latest sowing date (LSD), drying occurred from 14th September to 31st October, with variation coefficients of 1.3–3.0. In the changed harvest scenario, the drying time of maize sown on the OSD condition was from 12th September to 9th November with variation coefficients of 1.3–3.0, while maize sown on the LSD had drying dates of 26th September to 28th October with variation coefficients of 1.5–3.6. In the future harvest scenario, the Fengken 139 (FK139) and Jingnongke 728 (JNK728) hybrids finished drying on 20th October and 8th November, respectively, when sown on the OSD and had variation coefficients of 2.7–2.8. Therefore, the maize kernel drying time was gradually delayed and was associated with an increased demand for AT ⩾ 0°C late in the growing season. Furthermore, we observed variation among different growing seasons likely due to differences in weather patterns, and that sowing dates impact variations in drying times to a greater extent than harvest scenarios.

The CLEAR Trial recently found that decolonization reduced infections and hospitalizations in MRSA carriers in the year following hospital discharge. In this secondary analysis, we explored whether decolonization had a similar benefit in the subgroup of trial participants who harbored USA300, using two different definitions for the USA300 strain-type.