RESUMEN
The US Food Safety Modernization Act (FSMA) gives food safety regulators increased authority to require implementation of safety measures to reduce the contamination of produce. To evaluate the future impact of FSMA on food safety, a better understanding is needed regarding outbreaks attributed to the consumption of raw produce. Data reported to the US Centers for Disease Control and Prevention's Foodborne Disease Outbreak Surveillance System during 1998-2013 were analysed. During 1998-2013, there were 972 raw produce outbreaks reported resulting in 34 674 outbreak-associated illnesses, 2315 hospitalisations, and 72 deaths. Overall, the total number of foodborne outbreaks reported decreased by 38% during the study period and the number of raw produce outbreaks decreased 19% during the same period; however, the percentage of outbreaks attributed to raw produce among outbreaks with a food reported increased from 8% during 1998-2001 to 16% during 2010-2013. Raw produce outbreaks were most commonly attributed to vegetable row crops (38% of outbreaks), fruits (35%) and seeded vegetables (11%). The most common aetiologic agents identified were norovirus (54% of outbreaks), Salmonella enterica (21%) and Shiga toxin-producing Escherichia coli (10%). Food-handling errors were reported in 39% of outbreaks. The proportion of all foodborne outbreaks attributable to raw produce has been increasing. Evaluation of safety measures to address the contamination on farms, during processing and food preparation, should take into account the trends occurring before FSMA implementation.
Asunto(s)
Brotes de Enfermedades , Enfermedades Transmitidas por los Alimentos/epidemiología , Frutas/microbiología , Verduras/microbiología , Centers for Disease Control and Prevention, U.S./estadística & datos numéricos , Inocuidad de los Alimentos , Enfermedades Transmitidas por los Alimentos/etiología , Hongos , Humanos , Alimentos Crudos/microbiología , Estaciones del Año , Plantones/microbiología , Estados Unidos/epidemiología , United States Food and Drug Administration/legislación & jurisprudenciaRESUMEN
We report direct measurement of population dynamics in the excited state manifold of a nitrogen-vacancy (NV) center in diamond. We quantify the phonon-induced mixing rate and demonstrate that it can be completely suppressed at low temperatures. Further, we measure the intersystem crossing (ISC) rate for different excited states and develop a theoretical model that unifies the phonon-induced mixing and ISC mechanisms. We find that our model is in excellent agreement with experiment and that it can be used to predict unknown elements of the NV center's electronic structure. We discuss the model's implications for enhancing the NV center's performance as a room-temperature sensor.
RESUMEN
We examined multistate outbreaks attributed to raw tomatoes in the United States from 1990 to 2010. We summarized the demographic and epidemiological characteristics of 15 outbreaks resulting in 1959 illnesses, 384 hospitalizations, and three deaths. Most (80%) outbreaks were reported during 2000-2010; 73% occurred May-September. Outbreaks commonly affected adult (median age 34 years) women (median 58% of outbreak cases). All outbreaks were caused by Salmonella [serotypes Newport (n = 6 outbreaks), Braenderup (n = 2), Baildon, Enteritidis, Javiana, Montevideo, Thompson, Typhimurium (n = 1 each); multiple serotypes (n = 1)]. Red, round (69% of outbreaks), Roma (23%), and grape (8%) tomatoes were implicated. Most (93%) outbreaks were associated with tomatoes served predominantly in restaurants. However, traceback investigations suggested that contamination occurred on farms, at packinghouses, or at fresh-cut processing facilities. Government agencies, academia, trade associations, and the fresh tomato industry should consider further efforts to identify interventions to reduce contamination of tomatoes during production and processing.
Asunto(s)
Brotes de Enfermedades , Intoxicación Alimentaria por Salmonella/epidemiología , Salmonella/fisiología , Solanum lycopersicum/microbiología , Adulto , Brotes de Enfermedades/estadística & datos numéricos , Femenino , Humanos , Masculino , Salud Pública , Restaurantes , Salmonella/clasificación , Salmonella/genética , Salmonella/aislamiento & purificación , Intoxicación Alimentaria por Salmonella/microbiología , Intoxicación Alimentaria por Salmonella/mortalidad , Estados Unidos/epidemiologíaRESUMEN
We demonstrate an all-optical method for magnetic sensing of individual molecules in ambient conditions at room temperature. Our approach is based on shallow nitrogen-vacancy (NV) centers near the surface of a diamond crystal, which we use to detect single paramagnetic molecules covalently attached to the diamond surface. The manipulation and readout of the NV centers is all-optical and provides a sensitive probe of the magnetic field fluctuations stemming from the dynamics of the electronic spins of the attached molecules. As a specific example, we demonstrate detection of a single paramagnetic molecule containing a gadolinium (Gd(3+)) ion. We confirm single-molecule resolution using optical fluorescence and atomic force microscopy to colocalize one NV center and one Gd(3+)-containing molecule. Possible applications include nanoscale and in vivo magnetic spectroscopy and imaging of individual molecules.
RESUMEN
We propose and analyze a novel mechanism for long-range spin-spin interactions in diamond nanostructures. The interactions between electronic spins, associated with nitrogen-vacancy centers in diamond, are mediated by their coupling via strain to the vibrational mode of a diamond mechanical nanoresonator. This coupling results in phonon-mediated effective spin-spin interactions that can be used to generate squeezed states of a spin ensemble. We show that spin dephasing and relaxation can be largely suppressed, allowing for substantial spin squeezing under realistic experimental conditions. Our approach has implications for spin-ensemble magnetometry, as well as phonon-mediated quantum information processing with spin qubits.
RESUMEN
We propose and analyze a physical system that naturally admits two-dimensional topological nearly flat bands. Our approach utilizes an array of three-level dipoles (effective S=1 spins) driven by inhomogeneous electromagnetic fields. The dipolar interactions produce arbitrary uniform background gauge fields for an effective collection of conserved hard-core bosons, namely, the dressed spin flips. These gauge fields result in topological band structures, whose band gap can be larger than the corresponding bandwidth. Exact diagonalization of the full interacting Hamiltonian at half-filling reveals the existence of superfluid, crystalline, and supersolid phases. An experimental realization using either ultracold polar molecules or spins in the solid state is considered.
RESUMEN
We describe how strong resonant interactions in multimode optomechanical systems can be used to induce controlled nonlinear couplings between single photons and phonons. Combined with linear mapping schemes between photons and phonons, these techniques provide a universal building block for various classical and quantum information processing applications. Our approach is especially suited for nano-optomechanical devices, where strong optomechanical interactions on a single photon level are within experimental reach.
RESUMEN
BACKGROUND: Data on the long-term impact of SARS-CoV-2 infection in children and young people (CYP) are conflicting. We assessed evidence on long-term post-COVID symptoms in CYP examining prevalence, risk factors, type and duration. METHODS: Systematic search of published and unpublished literature using 13 online databases between 01/12/2019 and 31/07/2021. Eligible studies reported CYP ≤19 years with confirmed or probable SARS-CoV-2 with any symptoms persisting beyond acute illness. Random effects meta-analyses estimated pooled risk difference in symptom prevalence (controlled studies only) and pooled prevalence (uncontrolled studies also included). Meta-regression examined study characteristics hypothesised to be associated with symptom prevalence. Prospectively registered: CRD42021233153. FINDINGS: Twenty two of 3357 unique studies were eligible, including 23,141 CYP. Median duration of follow-up was 125 days (IQR 99-231). Pooled risk difference in post-COVID cases compared to controls (5 studies) were significantly higher for cognitive difficulties (3% (95% CI 1, 4)), headache (5% (1, 8)), loss of smell (8%, (2, 15)), sore throat (2% (1, 2)) and sore eyes (2% (1, 3)) but not abdominal pain, cough, fatigue, myalgia, insomnia, diarrhoea, fever, dizziness or dyspnoea. Pooled prevalence of symptoms in post-COVID participants in 17 studies ranged from 15% (diarrhoea) to 47% (fatigue). Age was associated with higher prevalence of all symptoms except cough. Higher study quality was associated with lower prevalence of all symptoms, except loss of smell and cognitive symptoms. INTERPRETATION: The frequency of the majority of reported persistent symptoms was similar in SARS-CoV-2 positive cases and controls. This systematic review and meta-analysis highlights the critical importance of a control group in studies on CYP post SARS-CoV-2 infection.
Asunto(s)
COVID-19 , Adolescente , Niño , Fatiga , Fiebre/etiología , Cefalea/complicaciones , Cefalea/etiología , Humanos , SARS-CoV-2RESUMEN
OBJECTIVES: Rates of psychiatric disorders are considerably elevated in young people with long term physical health conditions. Currently few children obtain effective mental health treatments in the context of long term physical health conditions, and ways to improve access to evidence-based mental health interventions are urgently needed. One approach is to deploy briefer, more economical, yet still evidence-based, treatments. The objective of this review was to evaluate the efficacy of brief interventions targeting psychiatric disorders in children and young people with long term physical health conditions. METHODS: Predefined terms relating to brief psychological interventions for psychiatric disorders in children with long term physical health conditions were used to search relevant databases. A systematic review and meta-analysis was carried out in accordance with the Cochrane guidelines. Two reviewers independently screened titles and abstracts, extracted the data and conducted risk of bias assessments. RESULTS: A total of 12 randomised controlled trials were found to meet the inclusion criteria of the review. Of those, three studies were suitable for meta-analysis. A large effect size in favour of brief cognitive behavioural therapy for anxiety was found (g = - 0.95, CI -1.49 to -0.041; p < .001) with non-significant moderate-substantial heterogeneity (I2 = 58%; p = .09). CONCLUSION: This review suggests there is preliminary evidence that brief interventions, based on cognitive behavioural principles, may benefit young people with an anxiety disorder in the context of a long term physical health condition. There was insufficient evidence to assess whether this held true for depression and disruptive behaviour.
Asunto(s)
Intervención en la Crisis (Psiquiatría)/métodos , Enfermedad/psicología , Trastornos Mentales/terapia , Intervención Psicosocial/métodos , Adolescente , Niño , Preescolar , Femenino , Humanos , MasculinoRESUMEN
The efficacy of breast self-examination (BSE) is limited by the extent to which women can be taught to perform a frequent and proficient examination. We randomized 783 women from a health maintenance organization into group instruction, individual instruction, individual instruction with a reminder system, or minimal intervention designed to simulate an office encounter where BSE was encouraged but not taught. The percentage of lumps 1 cm and smaller detected in silicone breast models, the number of false-positive detections, the search technique, and the self-reported BSE frequency were measured before and four months after intervention. Multiple tests for comparisons of interventions showed that the interventions containing BSE instruction were comparable in increasing true- and false-positive detection of lumps and in improving search technique, but the minimal intervention resulted in lower scores for all three outcomes (P less than .0001). Women in all four intervention groups increased their BSE frequency over the four-month follow-up period, but the greatest improvement in frequency was reported among women receiving reminders.
Asunto(s)
Mama , Educación del Paciente como Asunto/métodos , Autoexamen/métodos , Adulto , Reacciones Falso Positivas , Femenino , Humanos , Persona de Mediana Edad , Palpación/métodosRESUMEN
Stable quantum bits, capable both of storing quantum information for macroscopic time scales and of integration inside small portable devices, are an essential building block for an array of potential applications. We demonstrate high-fidelity control of a solid-state qubit, which preserves its polarization for several minutes and features coherence lifetimes exceeding 1 second at room temperature. The qubit consists of a single (13)C nuclear spin in the vicinity of a nitrogen-vacancy color center within an isotopically purified diamond crystal. The long qubit memory time was achieved via a technique involving dissipative decoupling of the single nuclear spin from its local environment. The versatility, robustness, and potential scalability of this system may allow for new applications in quantum information science.