Using atomic interference to probe atom-surface interaction

We show that atomic interference in the reflection from two suitably polarized evanescent waves is sensitive to retardation effects in the atom-surface interaction for specific experimental parameters. We study the limit of short and long atomic de Broglie wavelength. The former case is analyzed in the semiclassical approximation (Landau-Zener model). The latter represents a quantum regime and is analyzed by solving numerically the associated coupled Schroedinger equations. We consider a specific experimental scheme and show the results for rubidium (short wavelength) and the much lighter meta-stable helium atom (long wavelength). The merits of each case are then discussed.Comment: 11 pages, including 6 figures, submitted to Phys. Rev. A, RevTeX sourc

Safety of the Combination of PERC and YEARS Rules in Patients With Low Clinical Probability of Pulmonary Embolism: A Retrospective Analysis of Two Large European Cohorts

BACKGROUND: This study aimed to determine the failure rate of a combination of the PERC and the YEARS rules for the diagnosis of pulmonary embolism (PE) in the emergency department (ED). METHODS: We performed a retrospective analysis of two European cohorts of emergency patients with low gestalt clinical probability of PE (PROPER and PERCEPIC). All patients we included were managed using a conventional strategy (D-dimer test, followed, if positive, by computed tomographic pulmonary angiogram (CTPA). We tested a diagnostic strategy that combined PERC and YEARS to rule out PE. The primary endpoint was a thromboembolic event diagnosed in the ED or at 3-months follow-up. Secondary endpoints included a thromboembolic event at baseline in the ED and a CTPA in the ED. Ninety-five percent confidence intervals (CIs) of proportions were calculated with the use of Wilson\u27s continuity correction. RESULTS: We analyzed 1,951 patients (mean ± SD age = 47 ± 18 years, 56% women) with an overall proportion of patients with PE of 3.5%. Both PERC and YEARS strategies were associated with 11 missed PE in the ED: failure rate 0.57 (95% CI = 0.32-1.02). At 3-month follow-up, the overall failure rate was 0.83% (95% CI = 0.51-1.35). Among the 503 patients who underwent a CTPA (26%), the use of the PERC-YEARS combination would have ruled out PE without CTPA in 249 patients (50% [95%CI = 45%-54%], absolute reduction 13% (95% CI = 11%-14%]). CONCLUSION: The combination of PERC then YEARS was associated with a low risk of PE diagnostic failure and would have resulted in a relative reduction of almost half of CTPA

Pervasiveness of the IQ Rise: A Cross-Temporal Meta-Analysis

Background: Generational IQ gains in the general population (termed the Flynn effect) show an erratic pattern across different nations as well as across different domains of intelligence (fluid vs crystallized). Gains of fluid intelligence in different countries have been subject to extensive research, but less attention was directed towards gains of crystallized intelligence, probably due to evidence from the Anglo-American sphere suggesting only slight gains on this measure. In the present study, development of crystallized intelligence in the German speaking general population is assessed. Methodology/Principal Findings: To investigate whether IQ gains for crystallized intelligence are in progress in Germanspeaking countries, two independent meta-analyses were performed. By means of a cited reference search in ISI Web of Science, all studies citing test manuals and review articles of two widely-used salient measures of crystallized intelligence were obtained. Additionally, the electronic database for German academic theses was searched to identify unpublished studies employing these tests. All studies reporting participants mean IQ or raw scores of at least one of the two measures were included in the present analyses, yielding over 500 studies (.1,000 samples;.45,000 individuals). We found a significant positive association between years of test performance and intelligence (1971–2007) amounting to about 3.5 IQ points per decade. Conclusions/Significance: This study clearly demonstrates that crystallized IQ gains are substantial and of comparabl

Nivel de conocimientos de estudiantes de medicina sobre diagnóstico y manejo del infarto agudo del miocardio

Introduction: acute myocardial infarction is a disease with high morbidity and mortality.Objective: to determine the knowledge level of medical students about the diagnosis and management of acute myocardial infarction.Method: an observational, descriptive and cross-sectional study was carried out between January and February 2022 in medical students from the University of Medical Sciences of Pinar del Río who participated in the provincial update workshop on acute myocardial infarction. Through intentional sampling, a sample of 92 students was selected. To collect the information, a survey was used using Google Forms.Results: the female sex (65,21%), the age group from 21 to 22 years (65,21%) and the fourth-year students (50%) prevailed. Hypertension was the most identified risk factor (97,98%). 97,82% of the students identified precordial pain as the main clinical manifestation. 100% identified the presentation with complications, where sudden death was the most identified (81,52%). 100% point to the electrocardiogram as the main complementary, where ST alterations were the most identified (84,78%). 95,65% of the students indicated constant monitoring of vital parameters and cardiovascular function as the management measure.Conclusions: Medicine students belonging to the clinical area at the University of Medical Sciences of Pinar del Río have an adequate level of knowledge about the diagnosis and management of acute myocardial infarction.Introducción: el infarto agudo del miocardio constituye una enfermedad con elevada morbilidad y mortalidad.Objetivo: determinar el nivel de conocimientos de estudiantes de medicina sobre el diagnóstico y manejo del infarto agudo del miocardioMétodo: se realizó un estudio observacional, descriptivo y transversal entre enero y febrero de 2022 en estudiantes de Medicina de la Universidad de Ciencias Médicas de Pinar del Río del ciclo clínico que participaron en el Taller provincial de actualización sobre infarto agudo de miocardio. Mediante un muestreo intencional se seleccionó una muestra de 92 estudiantes. Para la recolección de la información se empleó una encuesta mediante Google Forms.Resultados: predominó el sexo femenino (65,21 %), el grupo etario de 21 a 22 años (65,21 %) y los estudiantes de cuarto año (50 %). La hipertensión fue el factor de riesgo más identificado (97,98 %). El 97,82 % de los estudiantes identificó el dolor precordial como principal manifestación clínica. El 100 % identificó la presentación con complicaciones, donde la muerte súbita fue la más identificada (81,52 %). El 100 % señala al electrocardiograma como principal complementario, donde las alteraciones del ST fueron las más identificada (84,78 %). El 95,65 % de los estudiantes indicaron la monitorización constante de los parámetros vitales y función cardiovascular como la medida de manejo.Conclusiones: los estudiantes de Medicina pertenecientes al área clínica en la Universidad de Ciencias Médicas de Pinar del Río poseen un adecuado nivel de conocimientos sobre el diagnóstico y manejo del infarto agudo del miocardio.  

La spectroscopie de saturation résolue en temps comme moyen d’étude des collisions élastiques

Nous présentons, en premier lieu, une introduction très simplifiée à la spectroscopie de saturation en présence de collisions tendant à thermaliser les vitesses atomiques. Ensuite nous posons le problème de la détermination du noyau de collision, dans le cadre de l’ensemble des travaux sur les collisions atomiques et moléculaires. A l’aide d’un calcul très élémentaire (perturbation) mais au cours duquel nous signalons avec le maximum de rigueur les approximations faites, nous établissons la relation entre le noyau de collision et le spectre de saturation. Nous en déduisons l’intérêt des méthodes temporelles pour la détermination expérimentale du noyau. Enfin, dans une dernière partie, nous décrivons les résultats obtenus dans le cas du néon métastable (3P0) et les espoirs d’une confrontation réelle avec la théorie des collisions

Study of velocity-changing collisions by time resolved saturated absorption

By use of two stabilized CW dye lasers and of electrooptic choppers we have developed an experimental set-up which combines the advantages of high frequency resolution and time resolved spectroscopy. We use this set-up to study the velocity thermalization of 1s3 metastable neon atoms. The collision kernel appears to be constituted of two components. The first one is broad and asymmetric, the second one is narrow and symmetric.L'usage de deux lasers à colorant continus, stabilisés, et de modulateurs électrooptiques permet de combiner les avantages de la spectroscopie à haute résolution et de la spectroscopie résolue en temps. Ce montage est utilisé pour l'étude de la thermalisation des vitesses d'atomes métastables de néon (1s3). Le noyau de collision apparaît formé de deux composantes, l'une large et asymétrique, l'autre étroite et symétrique

Forme de raie pour la spectroscopie d'absorption saturée tenant compte des collisions élastiques faibles

We use the Fourier transform with respect to axial velocity to derive a third-order line shape formula for high-resolution saturation spectroscopy that includes the effects of weak velocitychanging and quenching collisions, beam geometry, second-order Doppler shift, recoil splitting and laser frequency modulation. The inclusion of weak elastic collisions provides an explanation for the changes in the rates of pressure broadening with beam diameter. The derivation is easily applicable to experiments with spatially separated beams.En prenant la transformée de Fourier par rapport à la vitesse axiale des molécules, nous avons obtenu un profil de raie pour la spectroscopie de saturation à haute résolution qui tient compte des collisions élastiques et inélastiques, de la géométrie des faisceaux, de l'effet Doppler du 2e ordre, de l'effet de recul et de la modulation de fréquence du laser. L'inclusion des collisions élastiques d'angle faible permet d'expliquer la variation des taux d'élargissement par les collisions avec le diamètre des faisceaux. Le calcul s'applique aussi aux expériences à faisceaux séparés

Erratum : Forme de raie pour la spectroscopie d'absorption saturée tenant compte des collisions élastiques faibles

Pas de Résumé disponibl