Relative Delay Research Articles

Collision of two interacting electrons on a mesoscopic beam splitter: Exact solution in the classical limit

Experiments on collisions of isolated electrons guided along the edges in quantum Hall setups can mimic mixing of photons with the important distinction that electrons are charged fermions. In the so-called electronic Hong-Ou-Mandel (HOM) setup uncorrelated pairs of electrons are injected towards a beamsplitter. If the two electron wave packets were identical, Fermi statistics would force the electrons to scatter to different detectors, yet this quantum antibunching may be confounded by Coulomb repulsion. Here we model an electronic HOM experiment using a quadratic 2D saddle point potential for the beamsplitter and unscreened Coulomb interaction between the two injected electrons subjected to a strong out-of-plane magnetic field. We show that classical equations of motion for the drift dynamics of electrons' guiding centers take on the form of Hamilton equations for canonically conjugated variables subject to the saddle point potential and the Coulomb potential where the dynamics of the center-of-mass coordinate and the relative coordinate separate. We use these equations to determine collision outcomes in terms of a few experimentally tuneable parameters: the initial energies of the uncorrelated electrons, relative time delay of injection and the shape of the saddle point potential. A universal phase diagram of deterministic bunching and antibunching scattering outcomes is presented with a single energy scale characterizing the increase of the effective barrier height due to interaction of coincident electrons. We suggest clear-cut experimental strategies to detect the predicted effects and give analytical estimates of conditions when the classical dynamics is expected to dominate over quantum effects.

Detection of Speech-Language Delay in the Primary Care Setting: An Electronic Health Record Investigation.

The purpose of this study is to determine the rate and age at first identification of speech-language delay in relation to child sociodemographic variables among a pediatric primary care network. We analyzed a deidentified data set of electronic health records of children aged 1- to 5-years-old seen between 2015 and 2019 at 10 practices of a community-based pediatric primary health care network. Primary outcomes were numbers (proportions) of patients with relevant ICD-10 visit-diagnosis codes and patient age (months) at first documentation of speech-language delay. Regression models estimated associations between outcomes and patient characteristics, adjusting for practice affiliation. Of 14,559 included patients, 2063 (14.1%) had speech-language delay: 68.4% males, 74.4% with private insurance, and 96.1% with English as a primary household language. Most patients (60%) were first identified at the 18- or 24-month well-child visit. The mean age at first documentation was 25.4 months (SD = 9.3), which did not differ between practices reporting the use of standardized developmental screener and those using surveillance questionnaires. Regression models showed that males were more than twice as likely than females to be identified with speech-language delay (adjusted odds ratio [aOR] = 2.05, 95% CI: [1.86-2.25]); publicly insured were more likely than privately insured patients to be identified with speech-language delay (aOR = 1.48, 95% CI: [1.30-1.68]). Females were older than males at first identification (+1.2 months, 95% CI: [0.3-2.1]); privately insured were older than military insured patients (private +3.3 months, 95% CI: [2.2-4.4]). Pediatricians in this network identified speech-language delays at similar rates to national prevalence. Further investigation is needed to understand differences in speech-language delay detection across patient subgroups in practices that use developmental screening and/or surveillance.

A low-power 1 Gb/s line driver with configurable pre-emphasis for lossy transmission lines

A line driver with configurable pre-emphasis is implemented in a 65 nm CMOS process. The driver utilizes a three-tap feed-forward equalization architecture. The relative delays between the taps are selectable in increments of 1/16th of the unit interval via an 8-stage delay-locked loop and digital interpolator. It is also possible to control the output amplitude and source impedance for each tap via a programmable array of eight source-series terminated drivers. The entire design consumes 9 mW from a 1.2 V supply at 1 Gb/s.

Rapid Rescoping and Adaptation: An Evaluation of the Impact of COVID-19 on Postgraduate Medical Student Research Projects

The COVID-19 pandemic has adversely affected tertiary science and medical education, with significant impact on research-related activities. Research projects are a mandatory requirement of the Doctor of Medicine (MD) Program at the University of Sydney, and medical student projects are delivered across multiple sites in metropolitan and rural New South Wales, Australia. Several cohorts of medical students had projects that were affected by COVID-19. The aims of this study were to determine the impact of COVID-19 on medical student research projects and describe the measures taken to rescope projects, to support students in meeting the learning objectives of the program. Mandatory submission statements for all medical student research project scientific reports for 2020–2022 were examined for reports of the effect of COVID-19 on the project, including COVID-19 related delays, downsizing and the need to change research project types. During the study period, a total of 760 student reports were submitted, of which 217 (28.7%) were affected by COVID-19. About 50% were significantly delayed, 30% were downsized, and 6% required completely new projects. Rescoping arrangements implemented facilitated the successful completion of projects. Overall, the final student grades for the research projects were unaffected by COVID-19 or the related project rescoping. Whilst significantly impacted by COVID-19, medical student research projects were completed with provision of appropriate rescoping plans and academic support. Ensuring projects have a documented contingency plan secured projects as the pandemic progressed and will be a useful safeguard for all future project delivery.

Parent-reported Barriers and Parental Beliefs Associated with Intentions to Obtain HPV Vaccination for Children in a Primary care Patient Population in Minnesota, USA.

Human papillomavirus (HPV) vaccine uptake among adolescents remains suboptimal in the US. The COVID-19 pandemic posed new challenges to increase HPV vaccination rates. To characterize parent-reported barriers to obtain HPV vaccination for their children and to identify psychosocial factors associated with parents' intention to vaccinate their children for HPV, we administered parent surveys between April 2020 and January 2022 during a randomized pragmatic trial assessing the impact of evidence-based implementation strategies on HPV vaccination rates for adolescent patients at six Mayo Clinic primary care practices in Southeast Minnesota. A total of 342 surveys were completed (response rate 34.1%). Analyses were focused on parents of unvaccinated children (n = 133). The survey assessed the main reason the child did not receive the HPV vaccine, parental beliefs about the vaccine, and the parent's intention to vaccinate the child for HPV in the next 12 months. Frequently reported awareness and access barriers to HPV vaccination included not knowing the child was due (17.8%) and COVID-19 related delay (11.6%). Frequently reported attitudinal barriers include the belief that the child was too young for the vaccine (17.8%) and that the vaccine is not proven to be safe (16.3%). Injunctive social norm (Adjusted-OR = 3.15, 95%CI: 1.94, 5.41) and perceived harm beliefs (Adjusted-OR = 0.58, 95%CI: 0.35, 0.94) about the HPV vaccine were positively and negatively associated with HPV vaccination intention, respectively. Our findings suggest that continued efforts to overcome parental awareness, access, and attitudinal barriers to HPV vaccination are needed and underscore the importance of utilizing evidence-based health system-level interventions.

Few-femtosecond X-ray pulse generation and pulse duration control in a seeded free-electron laser

With the development of ultrafast science, free-electron lasers (FELs) with ultrashort pulses have become a state-of-the-art tool in ultrafast phenomena studies. In an externally seeded FEL, the output pulse duration is usually determined both by the seed laser pulse duration and FEL amplification process, which can hardly reach the timescale of a few femtoseconds. In this study, through a simple method of changing the relative time delay and correspondingly the pulse energy of the two seed lasers employed in a seeded FEL, we demonstrated the possibility of generating few-femtosecond soft X-ray pulses and controlling the final FEL pulse durations. Based on theoretical calculations and practical experiments, we conducted a detailed study on the capabilities and limitations to this method with the parameters of the Shanghai Soft X-ray FEL Facility. Start-to-end simulations indicate that we can achieve ultrashort soft X-ray FEL pulses with the pulse duration down to 5.2 fs, and the final pulse durations can also be controlled in terms of relative time delays.

Observation of Monoenergetic Electrons from Two-Pulse Ionization Injection in Quasilinear Laser Wakefields

The generation of low emittance electron beams from laser-driven wakefields is crucial for the development of compact x-ray sources. Here, we show new results for the injection and acceleration of quasimonoenergetic electron beams in low amplitude wakefields experimentally and using simulations. This is achieved by using two laser pulses decoupling the wakefield generation from the electron trapping via ionization injection. The injection duration, which affects the beam charge and energy spread, is found to be tunable by adjusting the relative pulse delay. By changing the polarization of the injector pulse, reducing the ionization volume, the electron spectra of the accelerated electron bunches are improved.

O.21.1 - Experiences of Patients and Relatives with COVID-19 related Delay or Change in Cancer Care: Presenter(s): Ilyse Kenis, KU Leuven, Belgium

O.21.1 - Experiences of Patients and Relatives with COVID-19 related Delay or Change in Cancer Care: Presenter(s): Ilyse Kenis, KU Leuven, Belgium

Experimental demonstration of magnitude-only bearing estimation

Traditional bearing estimation systems exploit relative time delays across an array of sensors to localize a target. While highly effective, such systems are costly and cumbersome. Yovel et al. (Science, 2010) found that bats steer their echolocation beams off axis to maximize the Fisher information, implying that spectral magnitude cues improve target localization. This presentation shares experiments demonstrating a man-made system estimating a target's bearing from echo spectrum magnitude-information using a single directional sensor with frequency dependence over the bandwidth of the signal. The output of a 31-element microphone array steered to broadside serves as the frequency dependent directional sensor. Moving a source transmitting a linear FM chirp across a range of angles estimates the beampattern of the receiver. Maximum likelihood estimation using these recorded replicas gives the mean-squared error (MSE) as a function of angle. The MSE is compared with the Cramer-Rao lower bound. Moving away from broadside reduces the received SNR, but paradoxically the MSE exhibits local minima. These MSE local minima are consistent with the optimal angles observed in previous research simulating the impact of magnitude cues (Kloepper et al., JASA-EL, 2018; Tidwell et al., IEEE SSPD, 2019). [Work supported by ONR MURI Program.]

Abstract P6-05-18: Reasons for Delay in Indian Women Presenting with Primary Stage III or IV Breast Cancer: An Observational Study

Abstract Background: Developing countries like India share higher burden of deaths due to breast cancer, despite having lower incidence than the west. Greater proportion of patients presenting with advanced stages of cancer is one of the reasons for this disparity. Since the factors leading to such delay have not been well studied in Indian patients, we decided to perform this study. Methodology: This was an observational study conducted from Jan 2021 to July 2022. Purposive Non-Random sampling was used and patients who had stage 3 or 4 breast cancer and were between 18-80 years of age were recruited. Interview was done on a one-to-one basis in a secluded area. Descriptive statistics were used, and chi-square was used to study the association of socio-demographic and clinical variables with the delay status of the breast cancer. Results: A total of 75 participants were enrolled in the study with mean age of 52.5 years and SD of 12.5 years. Out of these, 74 had lump as their first symptom. Only 14 of these 74 presented early i.e., within 3 months of onset of symptoms. Rest 60 participants presented late (more than 3 months after onset of symptoms). Between these two groups, difference in incidences of pregnancy associated lumps (0% in < 3 months vs 13.1% in ≥ 3 months, p=0.002), patients being afraid of treatment related complications (0% in < 3months vs 6.6% in ≥ 3 months, p=0.039) and their inability to decide because of lack of knowledge (0% in < 3months vs 6.6% in ≥ 3 months, p=0.039) were statistically significant. To our surprise, the thought that the lump was harmless and painless, embarrassment, limited access to healthcare and distance from the nearest healthcare facility, financial limitations, educational status, socio-economic status, family history of breast cancer, fear of mutilating surgeries and use of traditional medicine or spiritual care didn’t have significant effect on whether the patients presented within or after 3 months of onset of symptoms. On the question of COVID pandemic related delay, only 16% of all patients cited this as an additional reason for delay and this was again, not different between the patients who presented within or after 3 months of onset of symptoms. Conclusions: Health promotion in terms of proper evaluation of pregnancy related lumps and awareness about the management options of breast cancer may help patients to present earlier to healthcare facilities and may help in improving breast cancer related outcomes in developing countries like India. Citation Format: SIDDHANT KHARE, Vidushi Doda, R N NAGA SANTOSH IRRINKI. Reasons for Delay in Indian Women Presenting with Primary Stage III or IV Breast Cancer: An Observational Study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-05-18.

Optical transmitter for time-bin encoding quantum key distribution

We introduce an electro-optical arrangement that can produce time-bin encoded symbols with the decoy state method over a standard optical fiber in the C-band telecom window. The device consists of a specifically designed pulse pattern generator for pulse production and a field-programmable gate array that controls timing and synchronization. The electrical pulse output drives a sequence of intensity modulators acting on a continuous laser that deliver bursts of weak optical pulse pairs of discrete intensity values. Such a transmitter allows for the generation of all the quantum states needed to implement a discrete variable quantum key distribution (QKD) protocol over a single-mode fiber channel. Symbols are structured in bursts; the minimum relative delay between pulses is 1.25 ns, and the maximum symbol rate within a burst is 200 MHz. We tested the transmitter on simulated optical channels of 7 dB and 14 dB loss, obtaining maximum extractable secure key rates of 3.0 kb/s and 0.57 kb/s, respectively. Time-bin-state parameters such as the symbol rate, pulse separation, and intensity ratio between the signal and decoy states can be easily accessed and changed, allowing the transmitter to adapt to different experimental conditions and contributing to the standardization of QKD implementations.

Diagnosing the waveform of an ultrashort optical pulse by collinear interferometry

During the high-harmonic generation (HHG) process, information about field interaction with the medium is imprinted in the extreme ultraviolet (XUV) radiation. Here, we present a method for using HHG to diagnose the electric field of an optical pulse under a collinear geometry. When mixing a weak signal pulse with a strong driving pulse collinearly, the far field divergence of the XUV HHG is sensitive to the relative delay between the two pulses, which can be used as an ultrafast subcycle gate to reconstruct the electric field of the signal pulse. This collinear configuration is efficient, easy to operate and avoids artificial high order frequency components in reconstruction as compared to non-collinear schemes.

Fourier transform temporal diffusion spectroscopy

Temporal diffusion spectroscopy (TDS) currently uses the oscillating gradient spin echo (OGSE) experiment to measure the spectral density of translational velocity autocorrelation at single frequencies. Due to timing restrictions imposed by the transverse relaxation, the frequency selectivity and the sampling density of OGSE are limited, especially at low frequencies. We propose to overcome this problem by adopting the principles of Fourier transform spectroscopy. The new method of Fourier transform TDS (FTDS) uses two broadband gradient waveforms with different relative delays to make the spin echo attenuation sensitive to a broad range of diffusion frequencies with different harmonic modulations and calculates the spectrum by discrete Fourier transform. The method was validated by a measurement of diffusion spectra in highly restrictive tissues of a celery stalk and provided results consistent with OGSE, however, on a denser frequency grid.

P209 Delayed IBD diagnosis increases risk of requiring biologics in first 4-years - an Inception cohort study

Abstract Background Delays in diagnosis can be due to patient and health-system related factors. The impact of such delays in Inflammatory Bowel Diseases (IBD), particularly on biological therapies, continues to be of interest. The aim of the study was to investigate if delays could predict need for biologics and report on related adverse outcomes (AOs). Methods New patients referred for suspected IBD to a single tertiary care centre between Jan 2013 to Dec 2017 were identified using EMR. For this study, delay-types and cut-off times for each type were set based on best average hospital waiting times. The reasons for delays until start of treatment were recorded; data on the start of biologics, duration, and reasons for switch (if required) were recorded. Data was analysed using multiple Pearson correlations and Cox proportional Hazard model to determine whether any delay-types could predict need for biologics and compare the risk between patients with or without delay. Results 105 patients were identified using stringent criteria (M=58; median age=32y) with a median follow-up of 55 months. 65, 27 and 13 patients had a final diagnosis of Ulcerative colitis, Crohn’s disease, and Unclassified colitis respectively, and were analysed collectively. A model that combined delay in seeking medical attention, and time taken from specialty review to index endoscopy exhibited the best predictive power with average AUROC of 0.67. When individual delay-types were analysed, it was noted that most delay-types increased the risk of biologic use: a) delay in seeking medical attention [OR-1.08(1.03 1.17)] b) delay from GP referral to specialty review [OR-1.10(1.0 1.23)] c) delay from specialty review to index endoscopy [OR-1.09(1.01 1.21)] On further analysis, there was a statistically significant increase noted in the risk of requiring biologics at any time during the follow-up period. Fig 1A illustrates survival without biologics when there is a delay of >2 weeks in seeking medical attention (p=0.042). Figure 1B illustrates survival without biologics when there is delay of >6 weeks from GP referral to index endoscopy (p=0.021). Figure 1A- Patient-related delay of >2weeks and risk of needing biologics (p=0.042) Figure 1B- Health-system related delay of >6weeks and risk of needing biologics (p=0.021) Conclusion The risk of requiring biologic therapy is higher in those patients who have faced any type of delay in their diagnosis of IBD. A patient-related delay of >2weeks and cumulative health-system related delay of >6weeks increase the risk of requiring biologic therapy at any time during their follow-up. Both primary and secondary care must work to reduce any delays as this has long-term implications for patients and economic implications for health care providers.

Development of Cloud Autonomous System for Enhancing the Performance of Robots’ Path

With the development of computer technology and artificial intelligence (AI), service robots are widely used in our daily life. At the same time, the manufacturing cost of the robots is too expensive for almost all small companies. The greatest technical limitations are the design of the service robot and the resource sharing of the robot groups. Path planning for robots is one of the issues playing an important role in every application of service robots. Path optimization, fast computation, and minimum computation time are required in all applications. This paper aims to propose the Google Cloud Computing Platform and Amazon Web Service (AWS) platforms for robot path planning. The aim is to identify the effect and impact of using a cloud computing platform for service robots. The cloud approach shifts the computation load from robots to the cloud server. Three different path-planning algorithms were considered to find the path for robots using the Google Cloud Computing Platform, while with AWS, three different types of environments, namely dense, moderate, and sparse, were selected to run the path-planning algorithms for robots. The paper presents the comparison and analysis of the results carried out for robot path planning using cloud services with that of the traditional approach. The proposed approach of using a cloud platform performs better in this case. The time factor is crucially diagnosed and presented in the paper. The major advantage derived from this experiment is that as the size of the environment increases, the respective relative delay decreases. This proves that increasing the scale of work can be beneficial by using cloud platforms. The result obtained using the proposed methodology proves that using cloud platforms improves the efficiency of path planning. The result reveals that using the cloud computing platform for service robots can change the entire perspective of using service robots in the future. The main advantage is that with the increase in the scale of services, the system remains stable, while the traditional system starts deteriorating in terms of performance.

Reconfigurable optical diode based on asymmetrically coupled slow-light waveguide

Controlling the flow of light is fundamental for on-chip optical signal processing. In this paper, we investigate how to realize high contrast, high unidirectional transmission rate, and reconfigurable nonreciprocal light transmission, based on a nonlinear nanocavity asymmetrically side-coupled with a specially designed slow-light waveguide. We analytically and numerically demonstrate that the unusual multiple threshold pump power points for trigging the photon transitions between bistable states, as well as the sensitivity of the dynamic interactions to the relative delay time between the signal light and pump pulse, play crucial roles in this optical diode system. Based on these findings, a high contrast (over 22 dB) and high unidirectional transmission rate (over 70%) optical diode is achieved. More importantly, the conducting direction of the optical diode can be controllably reversed, without the need of changing the signal's wavelength or power as usually done. This approach is promising in the fields of optical information processing and quantum computing.

Rapid coherent Raman hyperspectral imaging based on delay-spectral focusing dual-comb method and deep learning algorithm.

Rapid coherent Raman hyperspectral imaging shows great promise for applications in sensing, medical diagnostics, and dynamic metabolism monitoring. However, the spectral acquisition speed of current multiplex coherent anti-Stokes Raman scattering (CARS) microscopy is generally limited by the spectrometer integration time, and as the detection speed increases, the signal-to-noise ratio (SNR) of single spectrum will decrease, leading to a terrible imaging quality. In this Letter, we report a dual-comb coherent Raman hyperspectral microscopy imaging system developed by integrating two approaches, a rapid delay-spectral focusing method and deep learning. The spectral refresh rate is exploited by focusing the relative delay scanning in the effective Raman excitation region, enabling a spectral acquisition speed of 36 kHz, ≈4 frames/s, for a pixel resolution of 95 × 95 pixels and a spectral bandwidth no less than 200 cm-1. To improve the spectral SNR and imaging quality, the deep learning models are designed for spectral preprocessing and automatic unsupervised feature extraction. In addition, by changing the relative delay focusing region of the comb pairs, the detected spectral wavenumber region can be flexibly tuned to the high SNR region of the spectrum.

Job satisfaction has differential associations with delay discounting and risk-taking

Low job satisfaction has been associated with both negative health and negative organizational outcomes. Knowledge on which factors influence job satisfaction remains limited. This study assesses the associations between job satisfaction and three personality traits related to cognitive- and inhibitory control: delay discounting, risk-taking and sensation seeking (DRS-traits). Delay discounting and sensation seeking were inferred using self-reported behavioral data and health measurements for 80,676 participants in the UK Biobank. Multiple linear regression analysis produced beta coefficients and confidence intervals for each DRS-trait and job satisfaction. Analyses were adjusted for age, socioeconomic status and sleep quality. A combination of the three DRS-traits (CDRS) was assessed as well. Delay discounting and risk-taking were associated with, respectively, lower and higher job satisfaction in both sexes. Sensation seeking had no significant association with job satisfaction for either sex. The combined score, CDRS, was only negatively associated with job satisfaction in females but not in males. We discuss that the negative association between delay discounting and job satisfaction may be due to career related delay discounting effects, but also highlight that low job satisfaction itself may also lead to increased delay discounting. Additionally, we discuss why increased risk-taking behavior may have a positive effect on job satisfaction.

Motivational beliefs moderate the relation between academic delay and academic achievement in online learning environments

Academic delay can be understood as individuals' behavioral postponement of their work in academic settings. The purpose of this study was to examine the relations between academic delay, motivational beliefs, and academic achievement in an online science course. The sample included one hundred and sixty-eight undergraduate students. Leveraging learning analytics and using multilevel modeling, this study found that academic delay was composed of habitual and momentary components. Controlling for motivational beliefs, habitual delay was significantly more negative than momentary delay in relation to academic achievement. The relation between academic delay and academic achievement was moderated by motivational beliefs. The negative effect of momentary delay on academic achievement was dependent on academic self-efficacy, while the negative effect of habitual delay on academic achievement was dependent on emotional cost. These findings further confirm that academic delay in online learning environments is not necessarily harmful for college students. Simply focusing on academic delay without considering who is engaging in such behavior could be misleading for future intervention.

Evaluation of InSAR Tropospheric Correction by Using Efficient WRF Simulation with ERA5 for Initialization

The delay caused by the troposphere is one of the major sources of errors limiting the accuracy of InSAR measurements. The tropospheric correction of InSAR measurements is important. The Weather Research and Forecasting (WRF) Model is a state-of-the-art mesoscale numerical weather prediction system designed for atmospheric research applications. It can be applied to InSAR tropospheric correction. Its parameters can be altered according to the requirements of the given application. WRF is usually initialized based on 3 h- or 6 h temporal resolution data in InSAR tropospheric correction studies, a lower temporal resolution compared to ERA5 data. A lower time resolution means a longer integration time for WRF to simulate from the initial time to the target time. Initialization with a higher resolution can shorten the integration time of the simulation theoretically and improve its accuracy. However, an evaluation of the effectiveness of ERA5_WRF for InSAR tropospheric correction is lacking. To evaluate the efficiency of WRF tropospheric correction, we used Reanalysis v5 (ERA5) from the European Centre for Medium-Range Weather Forecasts (ECMWF) for initialization to drive the WRF (ERA5_WRF) for efficient applications in InSAR. Three methods based on global atmospheric models—FNL_WRF (tropospheric correction method based on WRF driven by NCEP FNL), Generic Atmospheric Correction Online Service for InSAR (GACOS), and ERA5—were used to evaluate the corrective effects of ERA5_WRF. The reliability of ERA5_WRF in different scenarios with large tropospheric delay was evaluated from the spatial and temporal perspectives by considering seasonal, topographic, and climatic factors. Its applications in the local space showed that ERA5_WRF could adequately correct tropospheric delay. Benefits include its high-quality data sources and the simulation of WRF, and its application in different seasons had proven superior to other methods in terms of the corrective effects of elevation-related and spatially related delays in summer. By analyzing the data sources and downscaling methods of correction methods and weather conditions of cases, ERA5_WRF had superior performance under the condition of large content and hourly variation of tropospheric delay. Furthermore, WRF showed the potential for tropospheric correction when other higher-quality data appear in the future.