Probing molecules in gas cells of subwavelength thickness with high frequency resolution.

Miniaturizing and integrating atomic vapor cells is widely investigated for the purposes of fundamental measurements and technological applications such as quantum sensing. Extending such platforms to the realm of molecular physics is a fascinating prospect that paves the way for compact frequency metrology as well as for exploring light-matter interactions with complex quantum objects. Here, we perform molecular rovibrational spectroscopy in a thin-cell of micrometric thickness, comparable to excitation wavelengths. We operate the cell in two distinct regions of the electromagnetic spectrum, probing ν1 + ν3 resonances of acetylene at 1.530 µm, within the telecommunications wavelength range, as well as the ν3 and ν2 resonances of SF6 and NH3 respectively, in the mid-infrared fingerprint region around 10.55 µm. Thin-cell confinement allows linear sub-Doppler transmission spectroscopy due to the coherent Dicke narrowing effect, here demonstrated for molecular rovibrations. Our experiment can find applications extending to the fields of compact molecular frequency references, atmospheric physics or fundamental precision measurements.

Adolescent Feelings on COVID-19 Distance Learning Support: Associations With Mental Health, Social-Emotional Health, Substance Use, and Delinquency.

PURPOSE: School social support is associated with improved adolescent wellbeing. However, positive school relationships were potentially disrupted when schools transitioned to distance learning in 2020 to mitigate the spread of COVID-19. This study investigated associations among perceived distance learning school support, mental health, social-emotional wellbeing, substance use, and delinquency among low-income, public high school students. METHODS: We analyzed longitudinal survey data, collected between June 2020 and June 2021, from 372 students attending five large urban public high schools. Mixed-effects regression models examined associations among changes in distance learning support and changes in mental health, social-emotional wellbeing, substance use, and delinquency, controlling for time, social-demographics, and baseline health. RESULTS: In this predominantly Latinx (83%) sample, within-person increases in perceived distance learning support were associated with improved mental health, increased grit, increased self-efficacy, and decreased stress. Between-person differences in distance learning support indicated that students reporting greater support had improved mental and social-emotional outcomes. Although there were no within-person associations among distance learning support and hopelessness or delinquency, students with greater distance learning support (between-person) had lower levels of hopelessness and lower odds of engaging in any delinquent behavior. There were no associations between distance learning support and 30-day substance use. DISCUSSION: School social support, even without students physically on campus, may be critical to adolescent health behaviors and social-emotional outcomes.

Outcome of the AVID College Preparatory Program on Adolescent Health: A Randomized Trial.

BACKGROUND AND OBJECTIVES: Academic tracking is a widespread practice, separating students by prior academic performance. Clustering lower performing students together may unintentionally reinforce risky peer social networks, school disengagement, and risky behaviors. If so, mixing lower performing with high performing youth ("untracking") may be protective, leading to better adolescent health. METHODS: Advancement via Individual Determination (AVID), a nationally-disseminated college preparatory program, supports placing middle-performing students in rigorous college-preparatory classes alongside high-performing peers. We conducted the first randomized, controlled trial of AVID in the United States, randomizing 270 students within 5 large public high schools to receive AVID (AVID group) versus usual school programming (control group). Participants completed surveys at the transition to high school (end of eighth grade/ beginning of ninth grade) and the end of ninth grade. Intent-to-treat analyses tested whether AVID resulted in healthier social networks (primary outcome), health behaviors, and psychosocial wellbeing. RESULTS: At follow-up, AVID students had lower odds of using any substance (odds ratio [OR] 0.66, 95% confidence interval [CI] 0.48-0.89) and associating with a substance-using peer (OR 0.74, 95% CI 0.45-0.98), and higher odds of associating with a peer engaged in school (OR 1.73, 95% CI 1.11-2.70). Male AVID students had lower stress and higher self-efficacy, grit, and school engagement than control students (P < .05 for all). No adverse health effects among high-performing peers were observed. CONCLUSIONS: AVID positively impacts social networks, health behaviors, and psychosocial outcomes suggesting academic untracking may have substantial beneficial spillover effects on adolescent health.

Unexpected Anisotropy of the Electron and Hole Landé g-Factors in Perovskite CH3NH3PbI3 Polycrystalline Films.

In this work, we studied, at low temperature, the coherent evolution of the localized electron and hole spins in a polycrystalline film of CH3NH3PbI3 (MAPI) by using a picosecond-photo-induced Faraday rotation technique in an oblique magnetic field. We observed an unexpected anisotropy for the electron and hole spin. We determined the electron and hole Landé factors when the magnetic field was applied in the plane of the film and perpendicular to the exciting light, denoted as transverse ⟂ factors, and when the magnetic field was applied perpendicular to the film and parallel to the exciting light, denoted as parallel ∥ factors. We obtained |ge,⟂|=2.600 ± 0.004, |ge,∥|=1.604 ± 0.033 for the electron and |gh,⟂|=0.406 ± 0.002, |gh,∥|=0.299 ± 0.007 for the hole. Possible origins of this anisotropy are discussed herein.

Energy Tuning of Electronic Spin Coherent Evolution in Methylammonium Lead Iodide Perovskites.

We investigated the coherent evolution of the electronic spin at low temperature in high-quality CH3NH3PbI3 polycrystalline films by picosecond-resolved photoinduced Faraday rotation. We show that this coherent evolution can be tuned by choosing the pump-probe energy within the lowest optical-absorption band, and we explain it as the result of two main contributions: the localized electron and the localized hole. Their corresponding amplitude ratios are not constant across the lowest absorption band-an observation which disqualifies a free exciton from being at the origin of the electronic spin coherent evolution. We measured a spin coherence time of localized electrons (holes) of 4.4 ns (3.7 ns) at 1.635 eV, which evolves to about 7 ns at 1.612 eV (the hole coherence time remains almost constant at lower energies). Finally, we provide a global image of the spin coherent evolution in bulk metal halide perovskite, which overcomes recent controversies.

Efecto de las estrategias de conservación sanguínea sobre la transfusión en pacientes con circulación extracorpórea / Effect of blood conservation strategies on the transfusion for patients with extracorporeal circulation

Introducción: Los pacientes sometidos a cirugía cardiaca son candidatos a recibir múltiples transfusiones sanguíneas homólogas por causas como el sangrado; el desarrollo de estrategias de conservación sanguínea (ECS) ha permitido proteger al paciente y limitar el riesgo de enfermedades infectocontagiosas, inmunológicas e inflamatorias. Objetivo: Analizar el efecto de las estrategias de conservación sanguínea sobre la transfusión de hemoderivados en los pacientes sometidos a cirugía cardiaca con derivación cardiopulmonar. Material y métodos: Estudio no experimental, exploratorio y transversal. Muestra no probabilística (n = 105) incluyó a pacientes adultos y pediátricos sometidos a cirugía cardiopulmonar con circulación extracorpórea (CEC) que utilizaron las ECS. Recolección de datos con cédula ex profeso de las variables demográficas, hematológicas y transfusionales, CEC, ECS. Datos analizados con frecuencias, porcentajes, medidas de tendencia central y de dispersión; así como prueba de Pearson, U de Mann Whitney y T de Student; significancia p < 0.05. Resultados: Prevalecieron las valvulopatías (42%), cirugías correctivas (98%), tipo de sangre O+. Se recuperaron 120,511 ml de sangre, en promedio 1,161 ml por paciente. Tiempo de CEC relacionado con volumen sangre transfundido (r = 0.318, p = 0.000). Mayor número ECS en la cirugía correctiva (Z = -2.467, p = 0.014), en pacientes con cirugías previas se recupera un mayor volumen (t = 2.072, p = 0.039), cantidad de sangre transfundida durante la CEC es mayor en la bomba centrífuga (t = -4.022, p = 0.000), pero no hay diferencias por sexo (t = 1.488, p = 0.137). La hemoglobina y hematocrito antes y después de la CEC fue semejante (p > 0.05). Conclusiones: Las ECS son una excelente opción de uso para evitar la transfusión homóloga, ya que logran recuperar una gran cantidad de sangre autóloga, potencializándose sus beneficios. (AU)

Background: Patients undergoing cardiac surgery are eligible to receive multiple blood transfusions counterparts for reasons such as bleeding; the development of blood conservation strategies (BCS) has protected the patient and limit the risk of infectious, immunologic and inflammatory diseases. Objective: To analyze the effect of blood conservation strategies on blood transfusion in patients undergoing cardiac surgery with cardiopulmonary bypass. Material and methods: Non-experimental, exploratory and transversal study. Probabilistic sample (n = 105) included adult and pediatric patients undergoing ardiopulmonary surgery with extracorporeal circulation (ECC) using the BCS. Data collection with charter expressly demographic, blood transfusion and variables, ECC, BCS. Data analyzed using frequencies, percentages, measures of central tendency and dispersion; and Pearson test, Mann Whitney and tudent t; significance p < 0.05. Results: A prevalence of valvular heart disease (42%), corrective surgeries (98%), blood type O+. 120,511 ml blood was recovered 1,161 ml per patient. ECC time related to transfused blood volume (r = 0.318, p = 0.000). BCS largest number in corrective surgery (Z = 2467, p = 0.014) in patients with previous surgeries increased volume (t = 2.072, p = 0.039), amount of blood transfused during ECC is recovered is greater in the pump centrifuge (t = 4,022, p = 0.000), but no sex differences (t = 1.488, p = 0.137). Hemoglobin and hematocrit before and after ECC was similar (p > 0.05). Conclusions: The BCS is an excellent choice for use to avoid homologous transfusion, and who manage to recover a large amount of autologous, enhancing its benefits. (AU)

Técnica de hemofiltración veno-venosa continua / Technique of continuous veno-venous hemofiltration", "_i": "

La hemofiltración veno–venosa continua (HFVVC), es unatécnica realizada en pacientes postoperados de cirugía cardíaca;consiste en extraer agua plasmática del sistema circulatorio,a través de una membrana semipermeable (hemoconcentrador)por convección y gradiente de presión, con el objetivode disminuir hipervolemia, mejorar la función renal, eliminarmediadores de respuesta inflamatoria y optimizar el estado hemodinámicode los pacientes. Este procedimiento es realizadopor el personal de enfermería de perfusión en la unidad de terapiaintensiva con un circuito que se arma y diseña en unárea blanca. Una de las principales ventajas que se le adjudicana las terapias de HFVVC, es la tolerancia hemodinámica ala extracción de grandes volúmenes de líquido en forma gradualy controlada, en pacientes en estado crítico.

The continuous veno-venous hemofiltration (HFVVC), is atechnique realized in post-operated patients of cardiac surgery;it consists of extracting plasmatic water of the circulatorysystem, through a semi permeable membrane (hemoconcentrador)by convection and pressure gradient, with the aimof diminishing hipervolemia, improving the renal function,to eliminate mediators of inflammatory answer and to optimizethe hemodinámico state of the patients. This procedureis realized by the personnel of perfusion infirmary in theunit of intensive therapy with a circuit that weapon and isdesigned in a white area. One of the main advantages thatare adjudged to the HFVVC therapies, is the tolerance haemodynamicsto the extraction of great volumes of liquid ingradual and controlled form, in patients in critical state.