Bidirectional Cascaded Superfluorescent Lasing in Air Enabled by Resonant Third Harmonic Photon Exchange from Nitrogen to Argon.

Cavity-free lasing in atmospheric air has stimulated intense research toward a fundamental understanding of underlying physical mechanisms. In this Letter, we identify a new mechanism-a third-harmonic photon mediated resonant energy transfer pathway leading to population inversion in argon via an initial three-photon excitation of nitrogen molecules irradiated by intense 261 nm pulses-that enables bidirectional two-color cascaded lasing in atmospheric air. By making pump-probe measurements, we conclusively show that such cascaded lasing results from superfluorescence rather than amplified spontaneous emission. Such cascaded lasing with the capability of producing bidirectional multicolor coherent pulses opens additional possibilities for remote sensing applications.

An Introduction to the Native and Non-Native Plant-Insect Interactions and Potential Pollinators of Puerto Williams and Yendegaia, Cabo de Hornos, Chile.

The Magellanic sub-Antarctic ecoregion of southern Chile represents one of the last remaining pristine areas on Earth, but there are knowledge gaps concerning the biodiversity and interactions of the regions' flora and fauna. Non-native insect species like Bombus terrestris and Vespula vulgaris are known to have detrimental influence on native populations through competition for resources/nesting habitat, larvae predation, and foreign pathogen introduction. However, their interactions with the native and non-native plants in the region and between introduced species are unknown. This study highlights the importance of further investigations documenting the region's biodiversity, native and non-native species interactions, and local pollinators.

Influence of incubation temperature, maternal effects, and paternity on quality of olive ridley hatchlings (Lepidochelys olivacea) from a mass-nesting beach in the Mexican Pacific.

Future climate change scenarios project that the increase in surface temperatures will affect ocean temperatures, inducing shifts in marine biodiversity. Sea turtles are species that are particularly vulnerable to the effects of climate change because temperature is a factor that influences embryonic development. We collected clutches of olive ridley turtles from a mass-nesting beach in the Mexican Pacific, which were incubated in ex situ conditions. When the hatchlings emerged, we measured the body condition index-which evaluates the weight-length relationship-and swim thrust, both were considered traits associated with fitness, termed "fitness proxies," and evaluated the effects of incubation temperature, maternal effects, and paternity on these fitness proxies. The body condition index was correlated positively and significantly with the arribada month and temperature during the last third of the incubation period but showed an inverse relationship with the maternal effect. While swim thrust was positively correlated with the maternal effect and the arribada month, there was an inverse relationship with incubation temperature during the first third of the period. Paternity, whether single or multiple, did not have a significant effect on either fitness proxies; however, it may have effects on the average fitness of a population of hatchlings. These results underscore the need to expand research on the sublethal effects of high incubation temperatures on the adaptation and survival of sea turtles, particularly in scenarios of rapid climate change.

Assessment of speech perception: A survey of speech-language-hearing therapists on their most frequent practices / Evaluación de la percepción del habla: encuesta a profesionales de la Fonoaudiología sobre sus prácticas más frecuentes

ABSTRACT Purpose: to characterize the practices of speech-language-hearing pathologists in Chile, regarding speech perception assessment in children and adolescents. Methods: an exploratory cross-sectional study carried out using a self-administered online survey to investigate knowledge and quantify trends in the practice of speech perception assessment, based on six focus groups with speech-language-hearing pathologists. The instrument was disseminated through the researchers' social media and contact networks. Descriptive statistical analysis was performed. Results: a total of 121 people responded to the survey, all of them being speech-language-hearing pathologists. These professionals, in Chile, highly value speech perception in child development, however, a large percentage of them do not assess it. Those who carry it out, reported a wide range of assessment practices. Conclusion: the results highlight the need for standardizing certain speech-language-hearing methods and the importance of understanding the assessment strategies in use to point out opportunities to improve both the assessment and subsequent therapeutic processes.

RESUMEN Objetivo: caracterizar las prácticas de los profesionales de la Fonoaudiología en Chile en torno a la evaluación de la percepción del habla en niños, niñas y adolescentes. Métodos: se realizó un estudio exploratorio de diseño transversal mediante una encuesta online autoadministrada diseñada para indagar en los saberes y cuantificar tendencias en la práctica de la evaluación de la percepción del habla. La encuesta fue confeccionada en base a seis grupos focales realizados con profesionales fonoaudiólogos. La difusión del instrumento se realizó a través de redes sociales y redes de contacto de los investigadores. El análisis estadístico realizado fue de carácter descriptivo. Resultados: un total de 121 personas respondieron la encuesta, todos profesionales de la Fonoaudiología. Los profesionales de la Fonoaudiología en Chile otorgan un alto valor a la percepción del habla en el desarrollo infantil, no obstante, un gran porcentaje no la evalúa. Aquellos profesionales que lo realizan, revelan una amplia diversidad en las prácticas evaluativas. Conclusión: los resultados permiten visibilizar la necesidad de estandarizar ciertos métodos fonoaudiológicos y resaltar la importancia de comprender las estrategias evaluativas en uso para señalar oportunidades de mejora tanto en la evaluación como en los posteriores procesos terapéuticos.

Simulation of spatiotemporal light dynamics based on the time-dependent Schrödinger equation.

We establish a first-principle model for the simulation of spatiotemporal light pulse dynamics based on the combination of the time-dependent Schrödinger equation and the unidirectional propagation equation. The proposed numerical scheme enables computationally efficient simulation while being stable and accurate. We use the new model to examine self-focusing of a short pulse in atomic hydrogen and show that an accurate description of the excited-levels dynamics can only be achieved by a propagation model with an ab-initio description of the light-matter interaction, which accounts for the laser-dressed multilevel structure of the system, including bound and free states, and its sub-cycle response.

Microbiota Phenotype Promotes Anastomotic Leakage in a Model of Rats with Ischemic Colon Resection.

Anastomotic leakage (AL) is a major cause of morbidity and mortality after colorectal surgery, but the mechanism behind this complication is still not fully understood. Despite the advances in surgical techniques and perioperative care, the complication rates have remained steady. Recently, it has been suggested that colon microbiota may be involved in the development of complications after colorectal surgery. The aim of this study was to evaluate the association of gut microbiota in the development of colorectal AL and their possible virulence strategies to better understand the phenomenon. Using 16S rRNA sequencing of samples collected on the day of surgery and the sixth day following surgery, we analyzed the changes in tissue-associated microbiota at anastomotic sites created in a model of rats with ischemic colon resection. We discovered a trend for lower microbial diversity in the AL group compared to non-leak anastomosis (NLA). There were no differences in relative abundance in the different types of microbial respiration between these groups and the high abundance of the facultative anaerobic Gemella palaticanis is a marker species that stands out as a distinctive feature.

Imprinting Chirality on Atoms Using Synthetic Chiral Light Fields.

Atoms are usually thought of as achiral objects. However, one can construct superpositions of atomic states that are chiral [1]. Here, we show how to excite such superpositions with tailored light fields both in the weak-field and strong-field regimes, using realistic laser parameters. First, we use time-dependent Schrödinger equation simulations to demonstrate the creation of a time-dependent bound chiral wave packet in sodium atoms. Second, we show how the time-dependent handedness of this wave packet can be probed by photoelectron circular dichroism, in spite of the central symmetry of the core potential. Third, we use time-dependent Schrödinger equation simulations to show how chirality can be directly imprinted on a photoelectron wave packet created by strong-field ionization and introduce an unambiguous chiral measure that allows us to characterize its handedness.

Cross-polarized common-path temporal interferometry for high-sensitivity strong-field ionization measurements.

Absolute density measurements of low-ionization-degree or low-density plasmas ionized by lasers are very important for understanding strong-field physics, atmospheric propagation of intense laser pulses, Lidar etc. A cross-polarized common-path temporal interferometer using balanced detection was developed for measuring plasma density with a sensitivity of ∼0.6 mrad, equivalent to a plasma density-length product of ∼2.6 × 1013 cm-2 if using an 800 nm probe laser. By using this interferometer, we have investigated strong-field ionization yield versus intensity for various noble gases (Ar, Kr, and Xe) using 800 nm, 55 fs laser pulses with both linear (LP) and circular (CP) polarization. The experimental results were compared to the theoretical models of Ammosov-Delone-Krainov (ADK) and Perelomov-Popov-Terent'ev (PPT). We find that the measured phase change induced by plasma formation can be explained by the ADK theory in the adiabatic tunneling ionization regime, while PPT model can be applied to all different regimes. We have also measured the photoionization and fractional photodissociation of molecular (MO) hydrogen. By comparing our experimental results with PPT and MO-PPT models, we have determined the likely ionization pathways when using three different pump laser wavelengths of 800 nm, 400 nm, and 267 nm.

Cardiac function in critically ill patients with severe COVID: A prospective cross-sectional study in mechanically ventilated patients.

PURPOSE: To evaluate cardiac function in mechanically ventilated patients with COVID-19. MATERIALS AND METHODS: Prospective, cross-sectional multicenter study in four university-affiliated hospitals in Chile. All consecutive patients with COVID-19 ARDS requiring mechanical ventilation admitted between April and July 2020 were included. We performed systematic transthoracic echocardiography assessing right and left ventricular function within 24 h of intubation. RESULTS: 140 patients aged 57 ± 11, 29% female were included. Cardiac output was 5.1 L/min [IQR 4.5-6.2] and 86% of the patients required norepinephrine. ICU mortality was 29% (40 patients). Fifty-four patients (39%) exhibited right ventricle dilation out of whom 20 patients (14%) exhibited acute cor pulmonale (ACP). Eight out of the twenty patients with ACP exhibited pulmonary embolism (40%). Thirteen patients (9%) exhibited left ventricular systolic dysfunction (ejection fraction <45%). In the multivariate analysis acute cor pulmonale and PaO2/FiO2 ratio were independent predictors of ICU mortality. CONCLUSIONS: Right ventricular dilation is highly prevalent in mechanically ventilated patients with COVID-19 ARDS. Acute cor pulmonale was associated with reduced pulmonary function and, in only 40% of patients, with co-existing pulmonary embolism. Acute cor pulmonale is an independent risk factor for ICU mortality.

Non-instantaneous third-order optical response of gases in low-frequency fields.

It is commonly assumed that for low-intensity short optical pulses far from resonance, the third-order optical nonlinear response is instantaneous. We solve the three-dimensional time-dependent Schrödinger equation for the hydrogen atom and show that this is not the case: the polarization is not simply proportional to the cube of the electric field even at low intensities. We analyze the fundamental-frequency and third-harmonic nonlinear susceptibilities of hydrogen, investigate their dependence on intensity, and find that the delays in the Kerr response rapidly approach the femtosecond time-scale at higher intensities, while the delays in the third harmonic generation remain much lower. We also propose an experimental scheme to detect and characterize the above effects.

Critical care echocardiography in prone position patients during COVID-19 pandemic: a feasibility study.

PURPOSE: Critical care echocardiography is a fundamental tool in the hemodynamic evaluation of critically ill patients and prone position ventilation might limit its application. We aim to evaluate the feasibility of transthoracic echocardiography to assess different measurements performed in prone vs supine position in patients during COVID-19 pandemic to answer our research question: What is the feasibility of classic echocardiographic measurements in COVID-19 patients in prone position ventilation? METHODS: Patients with covid-19 admitted to ICUs in four academic hospitals with respiratory failure and on mechanical ventilation were evaluated with critical care echocardiography. The first ultrasound assessment was compared between prone and supine patients recording feasibility of several echocardiographic measurements, using Fisher's exact test complementing with Crombach's Alpha. RESULTS: 139 patients were included. Sixty-eight (49%) were evaluated in prone position and seventy one (51%) in supine position. Most variables were highly feasible, left ventricular volumes and ejection fraction were more possible to obtain in prone position, while cardiac output was in supine position. Tricuspid regurgitation was the least feasible overall measurement. CONCLUSION: Prone position ultrasound achieved a high feasibility of measurements compared with supine ultrasound in critically ill patients with COVID-19 respiratory failure and on mechanical ventilation. REGISTRATION: Post hoc analysis of Echo-COVID study (NTC04628195, registered November 13, 2020, retrospectively registered).

Non-Contact Acoustic Emission Monitoring of Corrosion under Marine Growth.

Offshore support structures and mooring systems are predominantly subject to corrosion and fatigue. These structures are typically covered with marine growth of various types. Conventional inspection methods for assessment of the structural integrity require access to the cleaned surface of these structures; however, the cleaning process is highly undesirable from the technical, economical, and environmental points of view. This paper highlights research on feasibility assessment of detection and localization of corrosion damage under marine growth using acoustic emission (AE). Experiments were conducted on two carbon steel plates, one baseline sample and one covered with artificially fabricated marine growth. The results of accelerated corrosion experiments suggest that corrosion-induced ultrasound signals can be detected with satisfactory signal-to-noise ratio using non-contact AE sensors. Ultrasound waves passing through marine growth showed around 12 dB drop in amplitude when compared to the base plate. A localization algorithm for corrosion induced-ultrasound signals was successfully implemented.

Propagator operator for pulse propagation in resonant media.

We show that, for the case of resonant media, the available models for unidirectional propagation of short pulses can face serious challenges with respect to numerical efficiency, accuracy, or numerical artifacts. We propose an alternative approach based on a propagator operator defined in the time domain. This approach enables precise simulations using short time windows even for resonant media and facilitates coupling of the propagation equation with first-principle methods such as the time-dependent Schödinger equation. Additionally, we develop a numerically efficient recipe to construct and apply such a propagator operator.

Novel antimicrobial cruzioseptin peptides extracted from the splendid leaf frog, Cruziohyla calcarifer.

Antimicrobial peptides (AMPs) constitute part of a broad range of bioactive compounds present on diverse organisms, including frogs. Peptides, produced in the granular glands of amphibian skin, constitute a component of their innate immune response, providing protection against pathogenic microorganisms. In this work, two novel cruzioseptins peptides, cruzioseptin-16 and -17, extracted from the splendid leaf frog Cruziohyla calcarifer are presented. These peptides were identified using molecular cloning and tandem mass spectrometry. Later, peptides were synthetized using solid-phase peptide synthesis, and their minimal inhibitory concentration and haemolytic activity were tested. Furthermore, these two cruzioseptins plus three previously reported (CZS-1, CZS-2, CZS-3) were computationally characterized. Results show that cruzioseptins are 21-23 residues long alpha helical cationic peptides, with antimicrobial activity against E. coli, S. aureus, and C. albicans and low haemolytic effect. Docking results agree with the principal action mechanism of cationic AMPs that goes through cell membrane disruption due to electrostatic interactions between cationic residues in the cruzioseptins and negative phosphate groups in the pathogen cell membrane. An action mechanism through enzymes inhibition was also tried, but no conclusive results about this mechanism were obtained.

In Situ Generation of High-Energy Spin-Polarized Electrons in a Beam-Driven Plasma Wakefield Accelerator.

In situ generation of a high-energy, high-current, spin-polarized electron beam is an outstanding scientific challenge to the development of plasma-based accelerators for high-energy colliders. In this Letter, we show how such a spin-polarized relativistic beam can be produced by ionization injection of electrons of certain atoms with a circularly polarized laser field into a beam-driven plasma wakefield accelerator, providing a much desired one-step solution to this challenge. Using time-dependent Schrödinger equation (TDSE) simulations, we show the propensity rule of spin-dependent ionization of xenon atoms can be reversed in the strong-field multiphoton regime compared with the non-adiabatic tunneling regime, leading to high total spin polarization. Furthermore, three-dimensional particle-in-cell simulations are incorporated with TDSE simulations, providing start-to-end simulations of spin-dependent strong-field ionization of xenon atoms and subsequent trapping, acceleration, and preservation of electron spin polarization in lithium plasma. We show the generation of a high-current (0.8 kA), ultralow-normalized-emittance (∼37 nm), and high-energy (2.7 GeV) electron beam within just 11 cm distance, with up to ∼31% net spin polarization. Higher current, energy, and net spin-polarization beams are possible by optimizing this concept, thus solving a long-standing problem facing the development of plasma accelerators.

Erratum: In Situ Generation of High-Energy Spin-Polarized Electrons in a Beam-Driven Plasma Wakefield Accelerator [Phys. Rev. Lett. 126, 054801 (2021)].

This corrects the article DOI: 10.1103/PhysRevLett.126.054801.

Risk Factors for Adult Depression: Adverse Childhood Experiences and Personality Functioning.

Background: Depressive disorder is one of the main health problems worldwide. Many risk factors have been associated with this pathology. However, while the association between risks factors and adult depression is well established, the mechanisms behind its impact remains poorly understood. A possible, yet untested explanation is the mediating impact of levels of personality functioning, i.e., impairments with regard to self and interpersonal. Method: Around 162 patients were assessed at the beginning of their therapy, with regard to risk factors, such as sociodemographic, physical, hereditary (Information Form), and adverse childhood experiences (ACE; CTQ). Depressive symptoms (Beck Depression Inventory, BDI) and personality functioning (OPD-SQ) were also measured. Associations between the related variables as well as other possible covariates were examined by means of zero-order correlations and bootstrapping-based mediation analysis. Results: Of all the risk factors taken into account, level of education and physical illness were associated with depression. On the other hand, the most significant predictor of depressive symptomatology was ACE, and this relationship was mediated by personality functioning. This indicates that patients presenting adverse childhood experiences are more likely to develop deficiencies in personality functioning, which in turn increases their likelihood of developing depressive symptomatology. Conclusion: These results reaffirm the importance of incorporating risk and vulnerability factors such as personality functioning in understanding depression.

Progression of regional lung strain and heterogeneity in lung injury: assessing the evolution under spontaneous breathing and mechanical ventilation.

BACKGROUND: Protective mechanical ventilation (MV) aims at limiting global lung deformation and has been associated with better clinical outcomes in acute respiratory distress syndrome (ARDS) patients. In ARDS lungs without MV support, the mechanisms and evolution of lung tissue deformation remain understudied. In this work, we quantify the progression and heterogeneity of regional strain in injured lungs under spontaneous breathing and under MV. METHODS: Lung injury was induced by lung lavage in murine subjects, followed by 3 h of spontaneous breathing (SB-group) or 3 h of low Vt mechanical ventilation (MV-group). Micro-CT images were acquired in all subjects at the beginning and at the end of the ventilation stage following induction of lung injury. Regional strain, strain progression and strain heterogeneity were computed from image-based biomechanical analysis. Three-dimensional regional strain maps were constructed, from which a region-of-interest (ROI) analysis was performed for the regional strain, the strain progression, and the strain heterogeneity. RESULTS: After 3 h of ventilation, regional strain levels were significantly higher in 43.7% of the ROIs in the SB-group. Significant increase in regional strain was found in 1.2% of the ROIs in the MV-group. Progression of regional strain was found in 100% of the ROIs in the SB-group, whereas the MV-group displayed strain progression in 1.2% of the ROIs. Progression in regional strain heterogeneity was found in 23.4% of the ROIs in the SB-group, while the MV-group resulted in 4.7% of the ROIs showing significant changes. Deformation progression is concurrent with an increase of non-aerated compartment in SB-group (from 13.3% ± 1.6% to 37.5% ± 3.1%), being higher in ventral regions of the lung. CONCLUSIONS: Spontaneous breathing in lung injury promotes regional strain and strain heterogeneity progression. In contrast, low Vt MV prevents regional strain and heterogeneity progression in injured lungs.

Physical demands of para-footballers with cerebral palsy in a small-sided game.

BACKGROUND: Cerebral palsy (CP) Football is a para-sport performed by individuals with physical impairments of athetosis, ataxia, or hypertonia. However, little is known about the physical demands of para-footballers with CP, and no previous study has analysed those demands in a small-sided game (SSG). This study aims to describe physical parameters using a global positioning system device in a SSG played by CP football players. METHODS: Fourteen male international para-footballers with CP took part in this study, which analysed their performance in an SSG of 3 vs. 3 players plus a goalkeeper per team. Also, a group of 12 football players participated as a control group. RESULTS: The total distance covered by the CP footballers during the SSG was 1931.1±213.6 m, and the distance covered per minute was 71.2±9.3 m/min, having lower scores than the control group. The maximum speed reached was 20.1±1.8 km/h, with a metabolic power of 6.2±0.9 W/kg and lower scores than the control group. Players with the minimal eligible impairment in this para-sport (i.e., sport class FT8) covered a greater distance in high-speed zones compared to players with more severe impairments. CONCLUSIONS: This study demonstrated that para-footballers with CP exhibited lower physical performance in an SSG compared to regular football players. Additional studies are necessary to identify the best format of an SSG for football players with CP and its application for training and evidence-based classification.

Experiencia de manejo de pacientes críticos con COVID-19 en Hospital Barros Luco: análisis descriptivo en un hospital público de alta complejidad / Experience of managing critical patients with COVID-19 at Hospital Barros Luco: descriptive analysis in a high complexity public Hospital

RELEVANCIA: La pandemia por COVID-19 (Coronavirus Disease-2019) se origina en diciembre de 2019. En Chile, a la fecha se han reportado 13.037 fallecidos con un enorme costo y esfuerzo asistencial, siendo limitada aun la evidencia en Chile acerca de esta enfermedad. OBJETIVOS: Describir el perfil clínico y ventilatorio de los pacientes con COVID-19 que requirieron manejo en la Unidad de Cuidados Intensivos en un Hospital Terciario de la Región Metropolitana. MÉTODOS: Estudio descriptivo, observacional y retrospectivo. Se extrajeron los datos de 64 pacientes ingresados entre el 24 de Marzo y el 15 de Mayo de 2020 en la UCI del Hospital Ramón Barros Luco Trudeau en el Sector Sur de la Región Metropolitana. Los resultados primarios en el estudio fueron Mortalidad en UCI, Mortalidad Intrahospitalaria y Mortalidad a 28 días. RESULTADOS: La mortalidad en UCI fue del 20%, existiendo una asociación entre Hipertensión Arterial y Enfermedad más Grave. La obesidad se asoció con mayores días UCI. En cuanto al soporte ventilatorio, 75% de los pacientes requirió apoyo con VMI al ingreso. Existe un perfil de mejor Compliance pulmonar y bajo potencial de reclutamiento durante la primera semana. Sin embargo, entre el 7mo. y 14vo día de enfermedad existe una rápida progresión hacia menor compliance pulmonar en cierto grupo de pacientes. CONCLUSIONES: Los casos más graves de COVID-19 se dan en pacientes de avanzada edad, hipertensos y obesos, con un aumento significativo en mortalidad cuando asociaron enfermedad renal crónica sobre todo en hemodiálisis. La progresión hacia deterioros severos de la elastancia pulmonar probablemente constituyen el signo ominoso de la enfermedad.