Two-particle time-domain interferometry in the fractional quantum Hall effect regime

Quasi-particles are elementary excitations of condensed matter quantum phases. Demonstrating that they keep quantum coherence while propagating is a fundamental issue for their manipulation for quantum information tasks. Here, we consider anyons, the fractionally charged quasi-particles of the Fractional Quantum Hall Effect occurring in two-dimensional electronic conductors in high magnetic fields. They obey anyonic statistics, intermediate between fermionic and bosonic. Surprisingly, anyons show large quantum coherence when transmitted through the localized states of electronic Fabry-P\ue9rot interferometers, but almost no quantum interference when transmitted via the propagating states of Mach-Zehnder interferometers. Here, using a novel interferometric approach, we demonstrate that anyons do keep quantum coherence while propagating. Performing two-particle time-domain interference measurements sensitive to the two-particle Hanbury Brown Twiss phase, we find 53 and 60% visibilities for anyons with charges e/5 and e/3. Our results give a positive message for the challenge of performing controlled quantum coherent braiding of anyons

The Relationship Between Changes in Neighborhood Physical Environment and Changes in Physical Activity Among Children: A Prospective Cohort Study

BACKGROUND: Physical activity (PA) is associated with positive health outcomes over the entire life course. Many community-based interventions that promote PA focus on implementing incremental changes to existing facilities and infrastructure. The objective of this study was to determine if such upgrades were associated with increases in children\u27s PA. METHODS: Two cohorts of 3- to 15-year-old children (n = 599) living in 4 low-income New Jersey cities were followed during 2- to 5-year periods from 2009 to 2017. Data on children\u27s PA were collected at 2 time points (T1 and T2) from each cohort using telephone survey of parents; data on changes to existing PA facilities were collected yearly from 2009 to 2017 using Open Public Records Act requests, publicly available data sources, and interviews with key stakeholders. PA changes were categorized into six domains (PA facility, park, trail, complete street, sidewalk, or bike lane) and coded as new opportunity, renovated opportunity, or amenity. A scale variable capturing all street-related upgrades (complete street, sidewalk, and bike lane) was constructed. PA was measured as the number of days per week the child engaged in at least 60 min of PA. The association between change in PA between T1 and T2, ranging from - 7 to + 7, and changes to the PA environment was modeled using weighted linear regression controlling for PA at T1, child age, sex, race, as well as household and neighborhood demographic and socioeconomic characteristics. RESULTS: While most measures of the changes to the PA environment were not associated with change in PA between T1 and T2, the street-related upgrades were positively associated with the change in PA; specifically, for each additional standard deviation in street upgrades within a 1-mile radius of their homes, the change in PA was 0.42 (95% CI: 0.02, 0.82; p = 0.039) additional days. This corresponds to an 11% increase over the mean baseline value (3.8 days). CONCLUSIONS: The current study supports funding of projects aimed at improving streets and sidewalks in cities, as it was shown that incremental improvements to the PA environment near children\u27s homes will likely result in increased PA among children

Towards a formal account for software transactional memory

International audienceSoftware transactional memory (STM) is a concurrency control mechanism for shared memory systems. It is opposite to the lock based mechanism, as it allows multiple processes to access the same set of variables in a concurrent way. Then according to the used policy, the effect of accessing to shared variables can be committed (hence, made permanent) or undone. In this paper, we define a formal framework for describing STMs and show how with a minor variation of the rules it is possible to model two common policies for STM: reader preference and writer preference

Food Insecurity Prevalence Across Diverse Sites During COVID-19: A Year of Comprehensive Data

Key Findings NFACT includes 18 study sites in 15 states as well as a national poll, collectively representing a sample size of more than 26,000 people. Some sites have implemented multiple survey rounds, here we report results from 22 separate surveys conducted during the year since the COVID-19 pandemic began in March 2020. 18 out of 19 surveys in 14 sites with data for before and since the pandemic began found an increase in food insecurity since the start of the COVID-19 pandemic as compared to before the pandemic. In nearly all surveys (18/19) that measured food insecurity both before and during the pandemic, more Black, Indigenous, and People of Color (BIPOC) were classified as food insecure during the pandemic as compared to before it began. Prevalence of food insecurity for BIPOC respondents was higher than the overall population in the majority of surveys (19/20) sampling a general population. In almost all surveys (21/22), the prevalence of food insecurity for households with children was higher than the overall prevalence of food insecurity. Food insecurity prevalence was higher for households experiencing a negative job impact during the pandemic (i.e. job loss, furlough, reduction in hours) in nearly all surveys and study sites (21/22). Food insecurity prevalence in most sites was significantly higher before COVID-19 than estimates from that time period. Reporting a percent change between pre and during COVID-19 prevalence may provide additional information about the rate of change in food insecurity since the start of the pandemic, which absolute prevalence of food insecurity may not capture. Results highlight consistent trends in food insecurity outcomes since the start of the COVID-19 pandemic, across diverse study sites, methodological approaches, and time

On the Relative Expressive Power of Asynchronous Communication Primitives

In this paper, we study eight asynchronous communication primitives, arising from the combination of three features: arity (monadic vs polyadic data), communication medium (message passing vs shared dataspaces) and pattern-matching. Each primitive has been already used in at least one language appeared in literature; however, to uniformly reason on such primitives, we plugged them in a common framework inspired by the asynchronous-calculus. By means of possibility/impossibility of ‘reasonable ’ encodings, we compare every pair of primitives to obtain a hierarchy of languages based on their relative expressive power.

Sensoria Patterns: Augmenting Service Engineering with Formal Analysis, Transformation and Dynamicity

The IST-FET Integrated Project Sensoria is developing a novel comprehensive approach to the engineering of service-oriented software systems where foundational theories, techniques and methods are fully integrated into pragmatic software engineering processes. The techniques and tools of Sensoria encompass the whole software development cycle, from business and architectural design, to quantitative and qualitative analysis of system properties, and to transformation and code generation. The Sensoria approach takes also into account reconfiguration of service-oriented architectures (SOAs) and re-engineering of legacy systems. In this paper we give first a short overview of Sensoria and then present a pattern language for augmenting service engineering with formal analysis, transformation and dynamicity. The patterns are designed to help software developers choose appropriate tools and techniques to develop service-oriented systems with support from formal methods. They support the whole development process, from the modelling stage to deployment activities and give an overview of many of the research areas pursued in the Sensoria project

Schools’ Participation in the Community Eligibility Provision Affects Students’ Receipt of Emergency Benefits during the COVID-19 Pandemic

Pandemic Electronic Benefits Transfer (P-EBT) benefits were intended for families of school children who lost access to free or reduced-price school meals (FRPMs) during the COVID-19 pandemic-related school closures. In high-poverty communities, all students from schools participating in the Community Eligibility Provision (CEP) were automatically eligible for P-EBT benefits; in non-CEP schools, only students already participating in FRPMs—for which their parents submitted an individual application—were eligible for P-EBT benefits. Using publicly available data from 105 K-12 public schools located in 4 sizeable low-income New Jersey (NJ) cities, this study investigated the association between school CEP participation status and the reach of P-EBT benefits for eligible students. A generalized linear model with a logit link, a binomial family, and robust standard errors was used. Across all levels of FRPM eligibility based on students’ household income, as expected, almost all students from CEP schools received P-EBT benefits; significantly fewer received P-EBT benefits if they attended non-CEP schools, even when they were eligible for FRPMs. Our findings show that without changes to the qualification process for CEP, large numbers of eligible children will not receive the intended health benefits of federal meals programs or similar emergency relief initiatives. Expanding CEP eligibility and simplifying the process through which schools qualify would likely improve the uptake of federal meals programs and emergency interventions, and more effectively achieve their intent

Do Parental Perceptions of the Nutritional Quality of School Meals Reflect the Food Environment in Public Schools?

(1) Background: It is unknown whether parents’ perception of school meals, a determinant of student meal participation, align with the nutritional quality of meals served in schools. This study compares the healthfulness of foods offered in schools with parental perception of school meals at those same schools. (2) Method: Parents were asked to rate the healthfulness of school meals at their child’s school. Data on the types of foods offered were collected from public schools in four cities in New Jersey and matched with parent-reported data. Measures were developed to capture the presence of healthy and unhealthy items in the National School Lunch Program and the presence of a la carte offerings as well as vending machines. Multivariable analysis examined the association between parental perceptions of school meals and the school food measures after adjusting for covariates. (3) Results: Measures of the school food environment and parental perceptions were available for 890 pre-K to 12th grade students. No significant associations were observed between parental perceptions and food environment measures when examined one by one or in a comprehensive model. (4) Conclusions: Parents’ perception of the healthfulness of meals served do not align with the nutritional quality of foods offered at schools