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Imaging through turbid media leads to a great loss of information decreasing the image quality. This loss of quality is due to the light interaction with the medium, since part of the light will pass through it, but another part will be scattered generating a blurred image pattern. In this work we try to decrease this problem by adding an absorbent, eliminating part of the scattered radiation responsible for the turbidity. With this aim, we use graphene nanoplates as an absorbent and we also compare the experimental results with black carbon powder.

Relativistic fluids of divergence type constitute a special class of fluids whose states are determined from the knowledge of a scalar generating function χ and a dissipation tensor I μ ν i.e. a second rank, symmetric and traceless tensor. Both ( χ , I μ ν ) depend upon fourteen variables, known in the literature as Lagrange multipliers, and these multipliers satisfy a symmetric, quasilinear, first order system determined by ( χ , I μ ν ) . For particular choices of the generating function χ, this system can be symmetric-hyperbolic and causal. We show in this work that this characteristic property of fluids of divergence type originates in the overdetermined nature of their dynamical equations. Combining their overdetermined nature with the work of Friedrichs on overdetermined system of conservation laws with more recent work by Boillat, Ruggeri and coworkers, we prove that fluids of divergence type are locally determined by a vector potential depending upon the Lagrange multipliers. For the case where the dynamical variables describing fluid states contain a symmetric energy momentum tensor, this vector potential is the gradient of a scalar field and this field is precisely the generating function χ introduced by Pennisi and independently by Geroch and Lindblom. Examples of scalar generating functions χ are discussed where this system is a symmetric hyperbolic and causal system in an open vicinity of equilibrium states.

The yellowlegs shrimp Penaeus californiensis is an oceanic species that approaches the coastal zone for its reproduction. However, in the southern Gulf of California, this species also enters coastal lagoons to grow and reproduce. To test the hypothesis that the growth of P. californiensis differs between these two environments, monthly samplings of shrimp were made in the interior of the Navachiste coastal lagoon and its adjacent marine area. To determine growth, age groups were identified using the size structures over time. Five cases of the Schnute model were adjusted to the data, and the best case was selected using a multi-model selection approach. A sigmoid-shaped curve best represented the female data (case 2), and the inverted exponential curve (case 5; equivalent to the Von Bertalanffy growth function) was best for males. Average growth differed between sexes () but not between environments ().

To date, the impact, timeline and duration of COVID-19 pandemic remains unknown and more than ever it is necessary to provide safe pathways for cancer patients. Multiple triage systems for nonemergent surgical procedures have been published, but potentially curative cancer procedures are essential surgery rather than elective surgery. In the present and future scenario of our country, thoracic oncology teams may have the difficult decision of weighing the utility of surgical intervention against the risk for inadvertent COVID-19 exposure for patients and medical staff. In consequence, traditional pathways of surgical care must be adjusted to reduce the risk of infection and the use of resources. It is recommended that all thoracic cancer patients should be offered treatment according to the accepted standard of care until shortage of services require a progressive reduction in surgical cases. Here, we present a consensus of recommendations discussed by a multidisciplinary panel of experts on thoracic oncology and based on the best available evidence, and hope it will provide a modifiable framework of guidance for local strategy planners in thoracic cancer care services in Mexico. KEY POINTS: SIGNIFICANT FINDINGS OF THE STUDY: This article provides recommendations to guarantee the continuity of surgical care for thoracic oncology cases during COVID-19 pandemic, whilst maintaining the safety of patients and medical staff. WHAT THIS STUDY ADDS: This guideline is the result of an expert consensus on thoracic surgical oncology with recommendations adapted to medical, economic and social realities of Mexico.

This Letter communicates a new, to the best of our knowledge, designing framework of shearography. The three elementary functional parts of quantitative shearography, namely imaging, shearing, and phase shifting, are integrated into a single diffractive optical element (DOE), named a 3-in-1 phase mask. The idea breaks through the conventional designing routine of shearography, and converts it from the combination of individual optical elements to the spatial manipulation of phase. The slicing, splicing, and alternating strategy is proposed to generate the 3-in-1 phase mask from a given number of sequenced Fresnel lenses and a modified echelle grating. The operating component is merely a DOE, which renders the optics naturally coaxial. The delivered shearography system enjoys a super-compact configuration, a high level of robustness and stability, and the potential for implementing outside optics laboratories. Crucial system parameters, e.g., shear amount, shear direction, working distance, can be readily shifted on call by re-making the 3-in-1 phase mask. The future of the present idea is in its shape and seems promising with lithography, micromachining, and metasurfaces.

RESUMEN Introducción: La hiponatremia es la alteración electrolítica más frecuente en el paciente geriátrico. Existen evidencias que la asocian a un peor pronóstico en pacientes con insuficiencia cardiaca. Objetivo: Caracterizar los pacientes geriátricos ingresados con hiponatremia al ingreso e insuficiencia cardíaca. Método: Se realizó un estudio descriptivo, longitudinal y prospectivo durante el año 2018 en el Hospital Universitario Clínico Quirúrgico “Calixto García” que incluyó 260 pacientes con insuficiencia cardíaca e hiponatremia al ingreso. Para el análisis estadístico de los datos reutilizaron la prueba de chi cuadrada y el análisis multivariado de ANOVA para la asociación entre variables. Resultados: La edad media fue 72,6 ± 8,2, predominaron las mujeres (55,0 %). Prevaleció la puntuación de Charlson 3-4 (33,8 %), la fracción de eyección conservada, 70,8 %; clase funcional III, 33,8 %; estadía menor a 6 días, 43,1 % y fallecieron 51,9 % de la muestra estudiada. Se asociaron significativamente con la mortalidad al egreso, el índice de comorbilidad y la clase funcional III-IV, p< 0,05. Conclusiones: Existe una elevada mortalidad en pacientes geriátricos hospitalizados por insuficiencia cardiaca e hiponatremia al ingreso asociada a la presencia de comorbilidad y a la clasificación de la insuficiencia cardiaca.

Zusammenfassung Die Oberflächeneigenschaften, insbesondere die Rauheit, sind in der Industrie von großer Bedeutung. Derzeit gibt es zahlreiche Verfahren zur optischen Rauheitsmessung. Ziel der in diesem Artikel beschriebenen Arbeiten ist es, eine Verbesserung der in [1, 2] beschriebenen Verfahren zu erzielen. Da bei realen Rauheitsmessungen gekrümmte Streifen auftreten, wird das Verfahren durch eine lokale Ermittlung der Streifenausrichtung im Interferogramm erweitert. Durch die Richtungsbestimmung der Streifen kann eine hohe laterale Auflösung erzielt und Oberflächenunregelmäßigkeiten besser erkannt werden. Als Referenz im Messsystem wird ein räumlicher Lichtmodulator verwendet.

espanolEl diagnostico de COVID-19 en ninos es un reto clinico especialmente para los medicos generales pues su prevalencia es menor en la infancia, la sintomatologia es diversa y varia segun la edad. Los ninos pueden ser asintomaticos, presentar sintomatologia leve o incluso llegar a tener cuadros graves como el Sindrome Inflamatorio Multisistemico. El proposito de este articulo de revision es presentar la informacion cientifica mas importante sobre seroprevalencia, cuadro clinico y factores de riesgo asociados a esta enfermedad infecciosa en la infancia con el fin de aportar al diagnostico y manejo oportunos. EnglishThe diagnosis of COVID-19 in children is a clinical challenge, especially for general practitioners, since its prevalence is lower in childhood, the symptoms are diverse and vary according to age. Children can be asymptomatic, present mild symptoms or even have serious conditions such as Multisystemic Inflammatory Syndrome. The purpose of this review article is to present the most important scientific information on seroprevalence, clinical symptoms and risk factors associated with this infectious disease in childhood in order to contribute to the timely diagnosis and management.

The characteristics of a surface, particularly the roughness, play an important role in different fields of the industry and have to be considered to ensure quality standards. Currently, there are numerous sophisticated methods for measuring surface roughness but plenty of them cause long-term damage because they are in contact with the sample. This article presents a non-contact method to accurately determine small surface roughnesses resulting from the consideration of the depolarization effects caused by the rough surface. This technique can be applied as an extension in various roughness measurements and improves the approach of Chandley&rsquo, s technique, which does not take into account the depolarization of the light scattered by the sample. The experimental setup and the measurements are easy to perform. The essential component is a quarter wave plate, which is incorporated into a Michelson interferometer. With the resulting two different contrasts and the recorded intensities of the sample and the reference mirror, the surface roughness can be estimated straightforwardly. This article details the theoretical approach, followed by the experimental results and the corresponding uncertainties. The experimental results are compared with Chandley&rsquo, s method. In order to have reference roughness values of the samples, measurements with a stylus profilometer and with a confocal microscope are performed and compared.

A real-time, dual-sensitive shearography system using a single-wavelength laser was developed for simultaneous and dynamic in-plane and out-of-plane strain measurements. The shearography system is capable of measuring crack-tip deformation fields quantitatively. A spatial multiplexing technique based on Fourier transform is employed for simultaneous and dynamic multi-component phase retrieval. Two slit spatial filters and a common-path shearing interferometer are used to obtain an improved phase quality for crack-tip deformation measurements. Mode-I fracture experiments under three-point bending were conducted to validate the feasibility and the capability of this method.

Este artículo presenta resultados parciales de una investigación acerca de los procesos vividos de forma más significativa por los futuros profesores en Educación Primaria. La metodología es cualitativa,se aplicó un cuestionario y entrevista semiestructurada a doce sujetos, encontrando que gran parte de éstos señalan a las experiencias de observación y práctica docente como más significativas para ser idóneos en su posterior ejercicio profesional. En cambio, pocos señalan el peso de la vocación,el autodidactismo y contar con profesores comprometidos y capaces para la consolidación de sus competencias profesionales. Concluimos que los procesos formativos iniciales son diversos y complejos con impacto escaso en el dominio teórico y metodológico de los estudiantes normalistas próximos a egresar.

Este artículo expone los resultados parciales de una experiencia docente con un colectivo de doce estudiantes durante su último año de formación como licenciados en educación primaria; el propósito fue favorecer el desarrollo del pensamiento reflexivo de los integrantes. Como método de investigación se utilizó la sistematización de experiencias; los instrumentos metodológicos fueron rúbricas y cuestionarios para recuperar opiniones de los formadores así como la opinión y los sentimientos experimentados por los participantes al intentar articular la teoría con la práctica. Como dispositivo pedagógico se realizó un taller de producción de textos a partir del Seminario de Análisis del Trabajo Docente I y II. Se implementó el trabajo colaborativo y el cuestionamiento socrático.Los resultados dan cuenta de una evolución progresiva cualitativa del pensamiento reflexivo de los estudiantes.

A single-aperture common-path speckle interferometer with an unlimited shear amount is developed. This unlimited shear amount is introduced when a Wollaston prism is placed near the Fourier plane of a common-path interferometer, which is built by using a quasi- 4 f imaging system. The fundamentals of the shear amount and the spatial carrier frequency generation are analyzed mathematically, and the theoretical predictions are validated by a static experiment. Mode-I fracture experiments through the three-point bending are conducted to prove the feasibility and the capability of this method in full-field strain measurement with various shear amounts. A remarkable feature of this setup is that no tilt is required between the optical components to produce the unlimited shear amount in off-axis holography.

Shrimp of Farfantepenaeus californiensis (78 groups) and Litopenaeus stylirostris (14 groups) were caught in the northwestern fishing zones in Mexico during the 2014–2015 fishing season (September–February); both shrimp species have high commercial value. Muscle, hepatopancreas and exoskeleton were analyzed to determine their metal contents. For F. californiensis, the highest Cd, Pb and Zn contents were determined in specimens caught off the State of Baja California Sur (BCS) with 22.4 ± 8.9 (hepatopancreas), 2.83 ± 4.63 (muscle), and 748.5 ± 1567 (muscle) µg/g, in the regions off Mulege, Los Cabos and Los Cabos, respectively. For L. stylirostris, the fishing zone of Comundu (BCS) showed higher Cd (12.3 ± 11.5 µg/g), Cu (569.1 ± 646.5 µg/g) and Zn (549.7 ± 400.7 µg/g) contents; all values were determined in the hepatopancreas. Regarding the hazard quotient and total hazard quotient calculated in this study, the consumption of marine shrimp caught off NW Mexico does not represent a risk to human health (both

A temporal electronic speckle pattern interferometry (ESPI) system is proposed for in-plane rotation measurement. The relationship between the rotation angle and the phase change distribution is established and the rotation direction is indicated by the sign of the partial differential of the phase change distribution. Temporal phase modulation is applied in the proposed symmetric illumination ESPI system. The phase is recovered by the temporal intensity analysis method which uses the temporal evolution history of the light intensity. The system can perform dynamic measurements and provide results in off-line real-time. Preliminary experiments were carried out with a continuously rotating target to show the feasibility and the dynamic feature of the temporal ESPI system. At present, the mean absolute error of the experiment is 0.39 arcsec.

This article exposes the partial results of a teaching experience with a group of twelve students during their final year of training as teachers in primary education; the purpose was encouraging the development of reflective thinking of the members. As a method of research used the systematization of experiences; the methodological instruments were headings and questionnaires to retrieve opinions of the trainers as well as the opinion and feelings experienced by the participants when attempting to link theory with practice. As pedagogical device a workshop was held for the production of texts from the Seminar of analysis of teachers' work I and II. It was implemented collaborative work, and the Socratic questioning. The results give an account of a progressive evolution of qualitative reflective thinking of students.

This article presents partial results of a research about the processes lived in a more meaningful manner by the future teachers in primary education. The methodology is qualitative, a questionnaire and a semistructured interview were applied to twelve subjects, finding that a large part of them point to the experiences of observation and teaching practice as more significant to be suitable in their later professional practice. In contrast, few point to the weight of vocation, self taught and count with teachers engaged and capable for the consolidation of their professional skills. We conclude that the initial formative processes are diverse and complex with little impact on the theoretical and methodological domain of the teacher training students coming to graduating.

The inspection of technical surfaces is often performed by two-wavelength electronic speckle-pattern interferometry (ESPI) combined with a phase-shifting procedure. As in conventional specular interferometry, the characteristic fringe spacing in the generated interferogram is defined by the applied wavelengths and the sensitivity is therefore constant in one fringe pattern. Subsequently, this technique is limited to surface structures with similar phase gradients and low structural density. To measure more complex structures, a high-resolution generated reference wavefront (HRGW) is adapted to the measurement object for local sensitivity adaption. The feasibility of this principle is directly linked to the functionality of the used spatial light modulator (SLM). A key factor of a proper phase-control is the structural setup of the SLM. In this article, the general influence of the microstructure of SLMs in adaptive ESPI is evaluated.

The surface structure, especially the roughness, has a significant influence on numerous parameters, such as friction and wear, and therefore estimates the quality of technical systems. In the last decades, a broad variety of surface roughness measurement methods were developed. A destructive measurement procedure or the lack of feasibility of online monitoring are the crucial drawbacks of most of these methods. This article proposes a new non-contact method for measuring the surface roughness that is straightforward to implement and easy to extend to online monitoring processes. The key element is a liquid-crystal-based spatial light modulator, integrated in an interferometric setup. By varying the imprinted phase of the modulator, a correlation between the imprinted phase and the fringe visibility of an interferogram is measured, and the surface roughness can be derived. This paper presents the theoretical approach of the method and first simulation and experimental results for a set of surface roughnesses. The experimental results are compared with values obtained by an atomic force microscope and a stylus profiler.

Introduction: Primary malignant tumors of the trachea are rare, but they represent 90% of all tumors of the trachea. The ad- enoid cystic carcinoma is the second most frequent hystologic type of tumor growing in the trachea with aproximately 10 to 15% of all cases. Symptoms are unspecifi c and the most frequent are cough, hoarseness, dyspnea, wheezzing and stridor. Bronchoscopy is the study of choice to obtain tissue for histopathologic study. Surgery is the treatment of choice when possible. Methods: We present the case of a 59 years old female with an adenoid cystic carcinoma of the middle third of the trachea, treated with surgical resection, obtaining a complete resection, with no adyuvant therapy, and with 14 months follow-up without recurrence. Discussion and conclusions: Treatment of adenoid cystic carcinoma should be multidisciplinary. In our patient had forecast a rate of 5-year survival of 91% because it was a localized disease. We consider that patients with any type of tracheal tumor should be referred to a specialized center with experience in the treatment of tracheal pathology.

This paper describes a dual-directional shearography system to address the issue of two-dimensional characterization of the surface strain. A common-path configuration coupled with an additional light path is used to provide the shearing in two directions. One of the three interfering beams is shared by both directional shearograms to improve the light efficiency and enhance the robustness of the system. The two directional shearograms are carried by different spatial carriers to distinguish one from the other. The spatial carrier is introduced by the single-aperture-lens Wollaston prism configuration. Rather than the conventional method in which the aperture is fixed at the front focal point of the imaging lens, a general case is considered by introducing a variable distance between the aperture and the imaging lens. The influence of the aperture-lens distance on the spatial carrier is then analyzed, which enables the separate control of the shearing amount and the spatial carrier. Two types of dual-directional shearography are presented to demonstrate the feasibility and the flexibility of the system. Type I is the simultaneous dual lateral shearography in orthogonal directions, and Type II is the simultaneous lateral and radial shearography. The spatial carrier introduced by the single-aperture-lens Wollaston prism configuration is discussed, and a configuration in which the Wollaston prism and the aperture are located at different sides of the lens is recommended for further shearography applications.