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408 result(s) for "Chapman, Benjamin"
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Observation of Wave-Packet Branching through an Engineered Conical Intersection
Analog quantum simulators, which efficiently represent model systems, have the potential to provide new insight toward naturally occurring phenomena beyond the capabilities of classical computers. Incorporating dissipation as a resource unlocks a wider range of out-of-equilibrium processes such as chemical reactions. Here, we operate a hybrid qubit-oscillator circuit quantum electrodynamics simulator and model nonadiabatic molecular dynamics through a conical intersection. We identify dephasing of the electronic qubit as the mechanism that drives wave-packet branching when the corresponding oscillator undergoes large amplitude motion. Furthermore, we directly observe enhanced branching when the wave-packet passes through the conical intersection. Thus, the forces that influence a chemical reaction can be viewed from the perspective of measurement backaction in quantum mechanics—there is an effective measurement-induced dephasing rate that depends on the position of the wave packet relative to the conical intersection. Our results set the groundwork for more complex simulations of chemical dynamics using quantum simulators, offering deeper insight into the role of dissipation in determining macroscopic quantities of interest such as the quantum yield of a chemical reaction.
Quantum control of an oscillator with a Kerr-cat qubit
Bosonic codes offer a hardware-efficient strategy for quantum error correction by redundantly encoding quantum information in the large Hilbert space of a harmonic oscillator. However, experimental realizations of these codes are often limited by ancilla errors propagating to the encoded logical qubit during syndrome measurements. The Kerr-cat qubit has been proposed as an ancilla for these codes due to its theoretically-exponential noise bias, which would enable fault-tolerant error syndrome measurements, but the coupling required to perform these syndrome measurements has not yet been demonstrated. In this work, we experimentally realize driven parametric coupling of a Kerr-cat qubit to a high-quality-factor microwave cavity and demonstrate a gate set that would enable universal quantum control of the cavity. We measure the decoherence of the cavity in the presence of the Kerr-cat and discover excess dephasing due to heating of the Kerr-cat to excited states. By engineering frequency-selective dissipation to counteract this heating, we are able to eliminate this dephasing, thereby demonstrating a high on-off ratio of control. Our results pave the way toward using the Kerr-cat to fault-tolerantly measure error syndromes of bosonic codes. Biased noise qubits, which can selectively suppress certain types of noise, are advantageous for quantum error correction of bosonic codes. Here the authors make an important step in this direction by demonstrating quantum control of a harmonic oscillator with a biased noise qubit.
A Systematic Review of Listeria Species and Listeria monocytogenes Prevalence, Persistence, and Diversity throughout the Fresh Produce Supply Chain
Listeria monocytogenes is an increasing food safety concern throughout the produce supply chain as it has been linked to produce associated outbreaks and recalls. To our knowledge, this is the first systematic literature review to investigate Listeria species and L. monocytogenes prevalence, persistence, and diversity at each stage along the supply chain. This review identified 64 articles of 4863 candidate articles obtained from four Boolean search queries in six databases. Included studies examined naturally detected/isolated Listeria species and L. monocytogenes in fresh produce-related environments, and/or from past fresh produce associated outbreaks or from produce directly. Listeria species and L. monocytogenes were detected in each stage of the fresh produce supply chain. The greatest prevalence of Listeria species was observed in natural environments and outdoor production, with prevalence generally decreasing with each progression of the supply chain (e.g., packinghouse to distribution to retail). L. monocytogenes prevalence ranged from 61.1% to not detected (0.00%) across the entire supply chain for included studies. Listeria persistence and diversity were also investigated more in natural, production, and processing environments, compared to other supply chain environments (e.g., retail). Data gaps were identified for future produce safety research, for example, in the transportation and distribution center environment.
Widely Tunable On-Chip Microwave Circulator for Superconducting Quantum Circuits
We report on the design and performance of an on-chip microwave circulator with a widely (GHz) tunable operation frequency. Nonreciprocity is created with a combination of frequency conversion and delay, and requires neither permanent magnets nor microwave bias tones, allowing on-chip integration with other superconducting circuits without the need for high-bandwidth control lines. Isolation in the device exceeds 20 dB over a bandwidth of tens of MHz, and its insertion loss is small, reaching as low as 0.9 dB at select operation frequencies. Furthermore, the device is linear with respect to input power for signal powers up to hundreds of fW (≈103 circulating photons), and the direction of circulation can be dynamically reconfigured. We demonstrate its operation at a selection of frequencies between 4 and 6 GHz.
A Systematic Review of the Use of Social Media for Food Safety Risk Communication
This article covers the current published literature related to the use of social media in food safety and infectious disease communication. The aim was to analyze literature recommendations and draw conclusions about how best to utilize social media for food safety risk communication going forward. A systematic literature review was conducted, and 24 articles were included for analysis. The inclusion criteria were (i) original peer-reviewed articles and (ii) primary focus on communication through social media about food safety and/or infectious diseases. Studies were coded for themes about social media applications, benefits, limitations, and best practices. Trust and personal beliefs were important drivers of social media use. The wide reach, immediacy, and information gathering capacities of social media were frequently cited benefits. Suggestions for social media best practices were inconsistent among studies, and study designs were highly variable. More evidence-based suggestions are needed to better establish guidelines for social media use in food safety and infectious disease risk communication. The information gleaned from this review can be used to create effective messages for shaping food safety behaviors.
Cross-Contamination on Atypical Surfaces and Venues in Food Service Environments
Cross-contamination of raw food to other surfaces, hands, and foods is a serious issue in food service. With individuals eating more meals away from home, contracting a foodborne illness from a food service establishment is an increasing concern. However, most studies have concentrated on hands or food contact surfaces and neglected atypical and unusual surfaces (surfaces that are not typically identified as a source of cross-contamination) and venues. This review was conducted to identify atypically cross-contaminated surfaces and atypical venues where cross-contamination could occur that have not been examined thoroughly in the literature. Most surfaces that could be at risk for cross-contamination are frequently touched, are rarely cleaned and sanitized, and can support the persistence and/or growth of foodborne pathogens. These surfaces include menus, spice and condiment containers, aprons and coveralls, mobile devices and tablets, and money. Venues that are explored, such as temporary events, mobile vendors, and markets, are usually limited in space or infrastructure, have low compliance with proper hand washing, and provide the opportunity for raw and ready-to-eat foods to come into contact with one another. These factors create an environment in which cross-contamination can occur and potentially impact food safety. A more comprehensive cleaning and sanitizing regime encompassing these surfaces and venues could help mitigate cross-contamination. This review highlights key surfaces and venues that have the potential to be cross-contaminated and have been underestimated or not fully investigated. These knowledge gaps indicate where further work is needed to fully understand the role of these surfaces and venues in cross-contamination and how it can be prevented.
Blood Dehydroepiandrosterone and Dehydroepiandrosterone Sulfate as Pathophysiological Correlates of Chronic Pain: Analyses Using a National Sample of Midlife Adults in the United States
Abstract Objective Identifying biomarkers is a priority in translational chronic pain research. Dehydroepiandrosterone (DHEA) and its sulfated form, DHEA-S, are adrenocortical steroids in the blood with neuroprotective properties that also produce sex hormones. They may capture key sex-specific neuroendocrine mechanisms of chronic pain. Design Cross-sectional study. Methods Using data from 1,216 community-dwelling adults aged 34–84 from the Midlife in the United States (MIDUS) cohort, we examined blood DHEA and DHEA-S levels in association with chronic pain in men and women, adjusting for demographics, chronic diseases, medications including opioids, and psychosocial factors. If an association was found, we further explored dose-response relationships by the number of pain locations and the degree of pain interference. Results In women, chronic pain was associated with 0.072 lower (95% confidence interval [CI], –0.127 to –0.017) log10 DHEA-S µg/dL, with pain in one to two locations associated with 0.068 lower (95% CI, –0.131 to –0.006) and in three or more locations 0.071 lower (95% CI, –0.148 to 0.007) log10 DHEA-S (P for trend = 0.074). Furthermore for women, low-interference pain was associated with 0.062 lower (95% CI, –0.125 to –0.000), whereas high-interference pain was associated with 0.138 lower (95% CI, –0.233 to –0.043) log10 DHEA-S (P for trend = 0.004). Chronic pain was not associated with DHEA or DHEA-S levels in men or DHEA levels in women. Conclusions Chronic pain and its functional interference correspond to lower blood DHEA-S levels in women.
Personality Predicts Cognitive Function Over 7 Years in Older Persons
To determine whether Neuroticism as well as the less-studied dimensions the Five Factor Model of personality (Extraversion, Openness to Experience, Agreeableness, and Conscientiousness) were associated with 7-year trajectories of cognitive functioning in older persons. Primary analysis of existing clinical trial data. 602 persons of average age 79 at baseline. The NEO-Five Factor Inventory of personality, completed at baseline, and the Modified Mini-Mental State Examination measured every 6 months for 7 years. Controlling for demographics, baseline morbidities including depression, health behaviors, apolipoprotein E4 genotype, and self-rated health, higher Neuroticism was associated with worse average cognitive functioning and a steeper rate of decline over follow-up. Higher Extraversion and lower Openness were both associated with worse average cognitive functioning prospectively, while persons higher in Conscientiousness showed a slower rate of cognitive decline. In addition to Neuroticism, other dispositional tendencies appear prognostically relevant for cognitive functioning in older persons. More work is needed to understand the mechanisms by which traits operate, as well as whether mitigation of certain dispositional tendencies can facilitate a better course of cognitive function.
Mindfulness-Based Stress Reduction for Older Adults: Effects on Executive Function, Frontal Alpha Asymmetry and Immune Function
Background/Aims: Mindfulness-based stress reduction (MBSR) has enhanced cognition, positive emotion, and immunity in younger and middle-aged samples; its benefits are less well known for older persons. Here we report on a randomized controlled trial of MBSR for older adults and its effects on executive function, left frontal asymmetry of the EEG alpha band, and antibody response. Methods: Older adults (n = 201) were randomized to MBSR or waiting list control. The outcome measures were: the Trail Making Test part B/A (Trails B/A) ratio, a measure of executive function; changes in left frontal alpha asymmetry, an indicator of positive emotions or approach motivation; depression, mindfulness, and perceived stress scores, and the immunoglobulin G response to a protein antigen, a measure of adaptive immunity. Results: MBSR participants had a lower Trails B/A ratio immediately after intervention (p < 0.05); reduced shift to rightward frontal alpha activation after intervention (p = 0.03); higher baseline antibody levels after intervention (p < 0.01), but lower antibody responses 24 weeks after antigen challenge (p < 0.04), and improved mindfulness after intervention (p = 0.023) and at 21 weeks of follow-up (p = 0.006). Conclusions: MBSR produced small but significant changes in executive function, mindfulness, and sustained left frontal alpha asymmetry. The antibody findings at follow-up were unexpected. Further study of the effects of MBSR on immune function should assess changes in antibody responses in comparison to T-cell-mediated effector functions, which decline as a function of age.
Socioeconomic Status Interacts with Conscientiousness and Neuroticism to Predict Circulating Concentrations of Inflammatory Markers
Background Socioeconomic health disparities research may benefit from further consideration of dispositional factors potentially modifying risk associated with low socioeconomic status, including that indexed by systemic inflammation. Purpose This study was conducted to investigate interactions of SES and the Five-Factor Model (FFM) personality traits in predicting circulating concentrations of the inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP). Method Using a sample of middle-aged and older adults from the Midlife in the United States Survey (MIDUS) biomarker project ( N  = 978), linear regression models tested interactions of each FFM trait with a composite measure of SES in predicting IL-6 and CRP, as well as the explanatory role of medical morbidity, measures of adiposity, and health behaviors. Results SES interacted with conscientiousness to predict levels of IL-6 (interaction b  = .03, p  = .002) and CRP (interaction b  = .04, p  = .014) and with neuroticism to predict IL-6 (interaction b  = −.03, p  = .004). Socioeconomic gradients in both markers were smaller at higher levels of conscientiousness. Conversely, the socioeconomic gradient in IL-6 was larger at higher levels of neuroticism. Viewed from the perspective of SES as the moderator, neuroticism was positively related to IL-6 at low levels of SES but negatively related at high SES. Interactions of SES with both conscientiousness and neuroticism were attenuated upon adjustment for measures of adiposity. Conclusions Conscientiousness may buffer, and neuroticism amplify, excess inflammatory risk associated with low SES, in part through relationships with adiposity. Neuroticism may be associated with lower levels of inflammation at high levels of SES.