Synthetic Z 2 gauge theories based on parametric excitations of trapped ions

Resource efficient schemes for the quantum simulation of lattice gauge theories can benefit from hybrid encodings of gauge and matter fields that use the native degrees of freedom, such as internal qubits and motional phonons in trapped-ion devices. We propose to use a parametric scheme to induce a tunneling of the phonons conditioned to the internal qubit state which, when implemented with a single trapped ion, corresponds to a minimal Z2 gauge theory. To evaluate the feasibility of this scheme, we perform numerical simulations of the state-dependent tunneling using realistic parameters, and identify the leading sources of error in future experiments. We discuss how to generalize this minimal case to more complex settings by increasing the number of ions, moving from a single link to a Z2 plaquette, and to an entire Z2 chain. We present analytical expressions for the gauge-invariant dynamics and the corresponding confinement, which are benchmarked using matrix product state simulations

Patterns of situational engagement and task values in science lessons

Situational engagement is a key element in promoting students' maintained interest and focused attention in learning. Most research on students engagement has been variable-centered, and only few studies have examined situational patterns of student engagement. The present study used person-oriented approach (e.g., latent profile analysis with Mplus multigroup comparison and 3-step procedure) to examine patterns of students' situational engagement in science (e.g., situational interest, skills, and challenge), differences in the engagement patterns during regular vs. intervention science lessons, and the extent to which situational expectations and task values (e.g., attainment and utility values) are associated with engagement patterns. Chilean ninth grade students participated in the study using Experience Sampling Method (N = 77 students; 475 situational responses). Three patterns of engagement were identified: a) medium interest and skills (21% and 23% of the moments during regular/intervention lessons, b) high interest and skills (12% and 16%), and c) low interest, skills, and challenge (13% and 15%). Situational task values and expectations were positively associated with high and medium engagement patterns, especially during the regular science lessons.Peer reviewe

Breaking the entangling gate speed limit for trapped-ion qubits using a phase-stable standing wave

All laser-driven entangling operations for trapped-ion qubits have hitherto been performed without control of the optical phase of the light field, which precludes independent tuning of the carrier and motional coupling. By placing 88Sr+ ions in a λ=674  nm standing wave, whose relative position is controlled to ≈λ/100, we suppress the carrier coupling by a factor of 18, while coherently enhancing the spin-motion coupling. We experimentally demonstrate that the off-resonant carrier coupling imposes a speed limit for conventional traveling-wave Mølmer-Sørensen gates; we use the standing wave to surpass this limit and achieve a gate duration of 15  μs, restricted by the available laser power

Base de datos de mediciones de respuestas impulsivas de recintos con diferentes características acústicas

La respuesta impulsiva de un recinto (RIR) engloba la característica de transmisión de lasondas sonoras entre una fuente y un receptor, asumiendo que el sistema es lineal e invariante en eltiempo. La respuesta impulsiva es diferente para cada ubicación de la dupla fuente-receptor y varíasegún la geometría y materiales, entre otros factores. En la actualidad el conocimiento de la RIRresulta imprescindible para el análisis y diseño de diversos recintos tales como salas de concierto,teatros, auditorios, salones de usos múltiples, ambientes industriales, oficinas, bibliotecas, ambientesespeciales (cámara anecóica y reverberante). La identificación de anomalías acústicas como ecosflotantes, resonancias, excesiva reverberación y otras, se realiza a través del análisis de la RIR. Lamedición de la RIR resulta útil también, para validar programas de simulación que se utilizan comoherramientas de diseño y sistemas de realidad acústica virtual. Actualmente existen varios métodos demedición de la RIR, siendo la ISO 3382 la norma de referencia que establece las directrices pararealizar dichas mediciones.En este trabajo se presentan los resultados de un conjunto de mediciones de RIR de espaciosarquitectónicos con diferentes características acústicas, efectuadas según norma ISO 3382. Elpropósito es difundir los resultados de dichas mediciones realizadas por el CINTRA con motivo deiniciar la construcción de una base de datos a nivel nacional e internacional que permita profundizarla investigación científica en temas referidos a la propagación de sonido en recintos, modos normalesde recintos, simulación acústica de recintos, realidad acústica virtual, diseño acústico arquitectónico,técnicas y métodos de medición en acústica de salas, entre otros.Fil: Cravero, Gabriel Agustín. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Transferencia en Acústica. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Transferencia en Acústica; ArgentinaFil: Ferreyra, Sebastian Pablo. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Transferencia en Acústica. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Transferencia en Acústica; ArgentinaFil: Ramos, Oscar Alberto. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Transferencia en Acústica. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Transferencia en Acústica; ArgentinaFil: Tommasini, Fabián Carlos. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Transferencia en Acústica. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Transferencia en Acústica; ArgentinaFil: Araneda, Mariano. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Transferencia en Acústica. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Transferencia en Acústica; Argentin

A hypoperfusion context may aid to interpret hyperlactatemia in sepsis-3 septic shock patients: a proof-of-concept study

__Background:__ Persistent hyperlactatemia is particularly difficult to interpret in septic shock. Besides hypoperfusion, adrenergic-driven lactate production and impaired lactate clearance are important contributors. However, clinical recognition of different sources of hyperlactatemia is unfortunately not a common practice and patients are treated with the same strategy despite the risk of over-resuscitation in some. Indeed, pursuing additional resuscitation in non-hypoperfusion-related cases might lead to the toxicity of fluid overload and vasoactive drugs. We hypothesized that two different clinical patterns can be recognized in septic shock patients through a multimodal perfusion monitoring. Hyperlactatemic patients with a hypoperfusion context probably represent a more severe acute circulatory dysfunction, and the absence of a hypoperfusion context is eventually associated with a good outcome. We performed a retrospective analysis of a database of septic shock patients with persistent hyperlactatemia after initial resuscitation. __Results:__ We defined hypoperfusion context by the presence of a ScvO2 < 70%, or a P(cv-a)CO2 ≥6 mmHg, or a CRT ≥4 s together with hyperlactatemia. Ninety patients were included, of whom seventy exhibited a hypoperfusion-related pattern and 20 did not. Although lactate values were comparable at baseline (4.8 ± 2.8 vs. 4.7 ± 3.7 mmol/L), patients with a hypoperfusion context exhibited a more severe circulatory dysfunction with higher vasopressor requirements, and a trend to longer mechanical ventilation days, ICU stay, and more rescue therapies. Only one of the 20 hyperlactatemic patients without a hypoperfusion context died (5%) compared to 11 of the 70 with hypoperfusion-related hyperlactatemia (16%). __Conclusions:__ Two different clinical patterns among hyperlactatemic septic shock patients may be identified according to hypoperfusion context. Patients with hyperlactatemia plus low ScvO2, or high P(cv-a)CO2, or high CRT values exhibited a more severe circulatory dysfunction. This provides a starting point to launch further prospective studies to confirm if this approach can lead to a more selective resuscitation strategy

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

Effects of alirocumab on types of myocardial infarction: insights from the ODYSSEY OUTCOMES trial

Aims  The third Universal Definition of Myocardial Infarction (MI) Task Force classified MIs into five types: Type 1, spontaneous; Type 2, related to oxygen supply/demand imbalance; Type 3, fatal without ascertainment of cardiac biomarkers; Type 4, related to percutaneous coronary intervention; and Type 5, related to coronary artery bypass surgery. Low-density lipoprotein cholesterol (LDL-C) reduction with statins and proprotein convertase subtilisin–kexin Type 9 (PCSK9) inhibitors reduces risk of MI, but less is known about effects on types of MI. ODYSSEY OUTCOMES compared the PCSK9 inhibitor alirocumab with placebo in 18 924 patients with recent acute coronary syndrome (ACS) and elevated LDL-C (≥1.8 mmol/L) despite intensive statin therapy. In a pre-specified analysis, we assessed the effects of alirocumab on types of MI. Methods and results  Median follow-up was 2.8 years. Myocardial infarction types were prospectively adjudicated and classified. Of 1860 total MIs, 1223 (65.8%) were adjudicated as Type 1, 386 (20.8%) as Type 2, and 244 (13.1%) as Type 4. Few events were Type 3 (n = 2) or Type 5 (n = 5). Alirocumab reduced first MIs [hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.77–0.95; P = 0.003], with reductions in both Type 1 (HR 0.87, 95% CI 0.77–0.99; P = 0.032) and Type 2 (0.77, 0.61–0.97; P = 0.025), but not Type 4 MI. Conclusion  After ACS, alirocumab added to intensive statin therapy favourably impacted on Type 1 and 2 MIs. The data indicate for the first time that a lipid-lowering therapy can attenuate the risk of Type 2 MI. Low-density lipoprotein cholesterol reduction below levels achievable with statins is an effective preventive strategy for both MI types.For complete list of authors see http://dx.doi.org/10.1093/eurheartj/ehz299</p

Effect of alirocumab on mortality after acute coronary syndromes. An analysis of the ODYSSEY OUTCOMES randomized clinical trial

Background: Previous trials of PCSK9 (proprotein convertase subtilisin-kexin type 9) inhibitors demonstrated reductions in major adverse cardiovascular events, but not death. We assessed the effects of alirocumab on death after index acute coronary syndrome. Methods: ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab) was a double-blind, randomized comparison of alirocumab or placebo in 18 924 patients who had an ACS 1 to 12 months previously and elevated atherogenic lipoproteins despite intensive statin therapy. Alirocumab dose was blindly titrated to target achieved low-density lipoprotein cholesterol (LDL-C) between 25 and 50 mg/dL. We examined the effects of treatment on all-cause death and its components, cardiovascular and noncardiovascular death, with log-rank testing. Joint semiparametric models tested associations between nonfatal cardiovascular events and cardiovascular or noncardiovascular death. Results: Median follow-up was 2.8 years. Death occurred in 334 (3.5%) and 392 (4.1%) patients, respectively, in the alirocumab and placebo groups (hazard ratio [HR], 0.85; 95% CI, 0.73 to 0.98; P=0.03, nominal P value). This resulted from nonsignificantly fewer cardiovascular (240 [2.5%] vs 271 [2.9%]; HR, 0.88; 95% CI, 0.74 to 1.05; P=0.15) and noncardiovascular (94 [1.0%] vs 121 [1.3%]; HR, 0.77; 95% CI, 0.59 to 1.01; P=0.06) deaths with alirocumab. In a prespecified analysis of 8242 patients eligible for ≥3 years follow-up, alirocumab reduced death (HR, 0.78; 95% CI, 0.65 to 0.94; P=0.01). Patients with nonfatal cardiovascular events were at increased risk for cardiovascular and noncardiovascular deaths (P<0.0001 for the associations). Alirocumab reduced total nonfatal cardiovascular events (P<0.001) and thereby may have attenuated the number of cardiovascular and noncardiovascular deaths. A post hoc analysis found that, compared to patients with lower LDL-C, patients with baseline LDL-C ≥100 mg/dL (2.59 mmol/L) had a greater absolute risk of death and a larger mortality benefit from alirocumab (HR, 0.71; 95% CI, 0.56 to 0.90; Pinteraction=0.007). In the alirocumab group, all-cause death declined wit h achieved LDL-C at 4 months of treatment, to a level of approximately 30 mg/dL (adjusted P=0.017 for linear trend). Conclusions: Alirocumab added to intensive statin therapy has the potential to reduce death after acute coronary syndrome, particularly if treatment is maintained for ≥3 years, if baseline LDL-C is ≥100 mg/dL, or if achieved LDL-C is low. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01663402

Battling to keep education going: chilean and portuguese teacher experiences in COVID-19 times

First Published online: 22 Dec 2021The article presents results of studies in Chile and Portugal during COVID-19 lockdowns and remote teaching conditions. In each of both countries, over two thousand teachers of all school levels and types were surveyed during a two-month period on their professional experiences in the first year of remote teaching. The article discusses teacher accounts of how their work changed, their difficulties, impact on well-being, as well as new professional learning brought about by the challenges involved. Conceptually, the study relied on notions of occupational professionalism, self-efficacy perceptionsand collegial support in challenging circumstances. Results in both countries highlighted an impact on teacher occupational professionalism and self-efficacy perceptions, mainly brought about by intermittent levels of engagement of students during remote teaching sessions, and difficulties in carrying out proper assessments of student learning. Student well-being was of greater concern to teachers than their own problems, despite feeling the stressful effect of much longer daily working hours, more so among Chilean than Portuguese teachers. The study also brought out teachers' imaginative efforts and the use of unaccustomed pedagogic strategies to reach out to students and insure some level of learning, especially among those without internet connectivity.This work was supported by the PIA-ANID Basal Funds for Centers of Excellence Project FB003 [Project FB003]; Portuguese National, Foundation for Science and Technology [Project UIDB/00317/2020 and UIDP/00317/2020]