La arquitectura cultural. / Cultural architecture.

Este artículo releva la Arquitectura Cultural, que es plural y diversa en términos estéticos y conceptuales. Sugiere la apertura a otras dinámicas de comprensión de lo arquitectónico, a otras lógicas de construcción de las ciudades. Para aclarar el concepto se expone un breve ejemplo práctico./This article points out the "cultural architecture", which is plural and diverse in concept and aesthetic terms. It suggests the opening to other dinamics of comprehention of the architectural issue and the building of cities. The article presents a brief empirical example that clarifies the conceptual approach

Performance analysis of the Least-Squares estimator in Astrometry

We characterize the performance of the widely-used least-squares estimator in astrometry in terms of a comparison with the Cramer-Rao lower variance bound. In this inference context the performance of the least-squares estimator does not offer a closed-form expression, but a new result is presented (Theorem 1) where both the bias and the mean-square-error of the least-squares estimator are bounded and approximated analytically, in the latter case in terms of a nominal value and an interval around it. From the predicted nominal value we analyze how efficient is the least-squares estimator in comparison with the minimum variance Cramer-Rao bound. Based on our results, we show that, for the high signal-to-noise ratio regime, the performance of the least-squares estimator is significantly poorer than the Cramer-Rao bound, and we characterize this gap analytically. On the positive side, we show that for the challenging low signal-to-noise regime (attributed to either a weak astronomical signal or a noise-dominated condition) the least-squares estimator is near optimal, as its performance asymptotically approaches the Cramer-Rao bound. However, we also demonstrate that, in general, there is no unbiased estimator for the astrometric position that can precisely reach the Cramer-Rao bound. We validate our theoretical analysis through simulated digital-detector observations under typical observing conditions. We show that the nominal value for the mean-square-error of the least-squares estimator (obtained from our theorem) can be used as a benchmark indicator of the expected statistical performance of the least-squares method under a wide range of conditions. Our results are valid for an idealized linear (one-dimensional) array detector where intra-pixel response changes are neglected, and where flat-fielding is achieved with very high accuracy.Comment: 35 pages, 8 figures. Accepted for publication by PAS

Optimality of the Maximum Likelihood estimator in Astrometry

The problem of astrometry is revisited from the perspective of analyzing the attainability of well-known performance limits (the Cramer-Rao bound) for the estimation of the relative position of light-emitting (usually point-like) sources on a CCD-like detector using commonly adopted estimators such as the weighted least squares and the maximum likelihood. Novel technical results are presented to determine the performance of an estimator that corresponds to the solution of an optimization problem in the context of astrometry. Using these results we are able to place stringent bounds on the bias and the variance of the estimators in close form as a function of the data. We confirm these results through comparisons to numerical simulations under a broad range of realistic observing conditions. The maximum likelihood and the weighted least square estimators are analyzed. We confirm the sub-optimality of the weighted least squares scheme from medium to high signal-to-noise found in an earlier study for the (unweighted) least squares method. We find that the maximum likelihood estimator achieves optimal performance limits across a wide range of relevant observational conditions. Furthermore, from our results, we provide concrete insights for adopting an adaptive weighted least square estimator that can be regarded as a computationally efficient alternative to the optimal maximum likelihood solution. We provide, for the first time, close-form analytical expressions that bound the bias and the variance of the weighted least square and maximum likelihood implicit estimators for astrometry using a Poisson-driven detector. These expressions can be used to formally assess the precision attainable by these estimators in comparison with the minimum variance bound.Comment: 24 pages, 7 figures, 2 tables, 3 appendices. Accepted by Astronomy & Astrophysic

Effect of the sludge recirculation rate on the performances of a two-stage anoxicsubmerged membrane bioreactor (A-SMBR) for the treatment of seafood wastewater

AbstractThe objective of this research is to study the effect of the sludge recirculation rate on the performance of two-stageanoxic-submerged membrane bioreactor (ASMBR) for the treatment of seafood wastewater. The seafood wastewater presents the biodegradable of containing high values of organic matter (COD around 2750 mg.L-1) and organic nitrogen compounds (TKN around 484 mg.L-1). Four values of recirculation rates, from 1/8 to 3 times the inflow rate, were studied during a long operational period. The MBR reactor was operated in subcritical flux conditions and no sludge extraction was done during the whole experimental period. The overall efficiency for the COD and nitrogen compound removal rate was on average 95+3% and 98+2% respectively. The residual COD, TKN and NO3--N concentration in the effluent were 23+4 mg.L-1, 1.2+0.9 mg.L-1 and 29+9 mg.L-1 respectively. In terms of filtration, trans-membrane pressure (TMP) showed a small and constant values in the membrane reactor with a TMP value of around 5-10 mbars. Membrane fouling appeared linked with the soluble organic compound interactions on the membrane surface (irreversible fouling).The quality of treated water met with the standard of wastewater reusefor all classes (A to D) issued by USEPA

Estudio comparativo de los de signos vitales, en pacientes sanos (ASA I) sometidos a cirugía de exodoncia, con y sin sedación oral con Midazolam.

Tesis para optar al Título de Cirujano – DentistaResumen. Objetivo: el objetivo de este estudio fue comparar los signos vitales de pacientes sometidos a exodoncia con y sin sedación oral con midazolam. Método: 60 pacientes sanos entre 12 y 65 años de edad con indicación de exodoncia de una o más piezas dentarias, 30 de los cuales tenían indicación de ansiólisis con midazolam vía oral de 7.5 mg y 30 sin indicación de ansiólisis, se sometieron a medición de signos vitales (presión arterial, frecuencia cardiaca y saturación de oxigeno) durante el procedimiento de exodoncia, se registraron los signos vitales en 4 momentos operatorios: preanestesia, postanestesia, intervención y recuperación. Resultados: no se observan diferencias significativas en los signos vitales de los pacientes con ansiólisis y sin ansiólisis con midazolam. Conclusiones: el midazolam utilizado como ansiolítico en cirugía de exodoncias no modifica los signos vitales significativamente y se consideraría seguro para el uso clínico, sin embargo se recomienda evaluar otros parámetros no considerados en este estudio como el estrés pre quirúrgico con el objeto de evaluar las repercusiones sobre los signos vitales.Abstract. Aim: The aim of this study was to compare the vital signs of patients undergoing tooth extraction with and without oral sedation with midazolam. Methods: 60 healthy patients between 12 and 65 years with extraction indication in one or more teeth, 30 of them had the indication to take oral anxiolysis with midazolam of 7.5 mg and 30 without the indication of anxiolysis, the vital signs (arterial pressure, heart rate, oxygen saturation) were measured to them during the extraction procedure and registered in 4 operatory moments: anesthesia, preanesthesia, intervention and recovery Results: no significant difference in the vital signs of patients with and without anxiolysis with midazolam. Conclusions: midazolam used as an anxiolytic in surgery extractions not alter vital signs significantly and would be considered safe for clinical use, however it is recommended evaluate other parameters not considered in this study as the pre-surgical stress in order to assess the impact on vital sign

Influencia de mallas sombreadoras sobre caracteristicas morfologicas, fisiologicas y productivas de Vaccinium corymbosum L.

93 p.Se estudiaron las respuestas fisiológicas, vegetativas y reproductivas de arándano de arbusto alto (Vaccinum corymbosum L. cv. Elliott) a mallas foto-selectivas de diversos colores (negro, rojo y blanco) y niveles de sombra (25, 50 y 75%), además de un control a pleno sol, en ambientes contrastantes, Chillán-Chile y Michigan-USA. Las irradiaciones variaron fuertemente entre mallas; las rojas redujeron PAR y aumentaron la radiación infrarroja, las blancas redujeron radiación UV, y las negras cambiaron poco el espectro. Las tasas de asimilación de CO2 (en USA), aumentaron hasta 50-60% PAR, en ambas temporadas. Hubo correlación entre máxima actividad fotoquímica del PSII (Fv/Fm), contenido total de clorofila y relación Chl/N foliar (r ≥ -0.866) con %PAR, pero gs tuvo poca relación con %PAR. El contenido de agua foliar se correlacionó con %PAR en USA (r = -0.917), pero no en Chile. El área específica foliar se asoció con %PAR (r = -0.787 en USA y -0.742 en Chile). La temperatura del dosel aumentó con %PAR (r = 0.849), pero el potencial hídrico del xilema no se relacionó con %PAR. La densidad estomática se correlacionó significativamente con %PAR (r = 0.818). Las mallas afectaron PPFD transmitido a través del dosel. Dentro del dosel (90-180 cm sobre el piso del huerto) todas las mallas tuvieron > 700 µmol m-2 s-1 PPFD, aunque en las blancas penetró significativamente mayor radiación. Las yemas florales abiertas disminuyeron linealmente con mayor %PPFD, pero las yemas florales por caña y por brote aumentaron gradualmente con el aumento en radiación, hasta 50% PPFD. Las mallas atrasaron la madurez; los frutos maduros (%) en una cierta fecha disminuyeron exponencialmente con la reducción del %PPFD. Los sólidos solubles aumentaron linealmente (r = 0.927, P < 0.0001) y el contenido de agua disminuyó linealmente (r = 0.938, P < 0.0001) al aumentar %PPFD. El rendimiento tuvo relación curvilínea positiva con PPFD hasta 50%, en USA (2007) y Chile (2006/2007 y 2007/2008). La interacción color vs. sombra no fue significativa en ambas zonas. La calidad de la fruta tuvo interacciones significativas de color x sombra (peso, sólidos solubles y firmeza), y color x fecha de cosecha (peso, sólidos solubles y acidez titulable). Estos resultados indican que V. corymbosum se aclimata fuertemente al ambiente luminoso bajo mallas y que al reducir hasta 50% la luz directa (y la temperatura foliar) se mejora en general el comportamiento fotosintético y variables foliares. El %PAR tiene mayor efecto que la calidad de la luz sobre la respuesta fotosintética. En este contexto, la selección del nivel de sombra y color apropiados variarán según las necesidades específicas. Un nivel de sombra roja o blanca intermedio (40-60 %PPFD) sobre plantas maduras debiera entregar, en la mayor parte de los casos, un atraso aceptable en la cosecha sin efectos negativos en el retorno floral y la calidad de la fruta./ABSTRACT: Physiological, vegetative and reproductive responses of highbush blueberry (Vaccinum corymbosum L. cv. Elliott) to photo-selective nets of various colors (black, red and white) and shade levels (25, 50 and 75%), plus a full sun control, were studied in contrasting environments, Chillán-Chile and Michigan-USA. Irradiances varied greatly among nets; red ones reduced PAR and increased infrared radiation, white nets reduced UV radiation, and black nets changed little the spectrum. CO2 assimilation rates (in USA), increased up to 50-60% PAR, in both growing seasons. Maximum PSII photochemical activity (Fv/Fm), total chlorophyll content and total Chl/leaf N ratio were correlated (r ≥ -0.866) with %PAR, but gs was little related with %PAR. Leaf water content was correlated with %PAR in USA (r2 = -0.917), but not in Chile. Specific leaf area was associated with %PAR (r = -0.787 in USA and -0.742 in Chile). Canopy temperature increased with %PAR (r = 0.849), but xylem water potential was not related with %PAR. Stomatal density was significantly associated with %PAR (r = 0.818). Nets influenced PPFD transmitted through the canopy. Within the canopy (90-180 cm above the ground) all nets provided > 700 µmol m-2 s-1 PPFD, although white nets allowed significantly higher radiation to penetrate. Open flower buds decreased linearly as %PPFD increased, but flower buds/cane and flower buds/shoot increased gradually as radiation increased, up to 50% PPFD. Nets delayed maturity; mature fruit (%) in a given date decreased exponentially as %PPFD was reduced. Soluble solids increased linearly (r = 0.927, P < 0.0001) and fruit water content decreased linearly (r = 0.938, P < 0.0001) as %PPFD increased. Yield had a positive curvilinear relationship with light up to 50% PPFD, in both USA (2007) and Chile (2006/2007 and 2007/2008). The interaction color vs. shade was not significant in both sites

PANDEMIA Y ARQUITECTURA

A través de este texto, profesores y alumnos de diversas partes el mundo, pertenecientes al Máster Emergencia + Resiliencia del Instituto Universitario de Arquitectura de Venecia (IUAV, Italia), investigadores de la Universidad de Sassari (UNISS, Italia) y del estudio Architecture &amp; Human Rights en Dinamarca y Chile, buscan elaborar hipótesis sobre la crisis de salud que atraviesa actualmente nuestro planeta. Históricamente la arquitectura y urbanismo no han tenido gran presencia en las emergencias conocidas como Pandemias, a diferencia de las otras categorías donde si tienen cierta capacidad de acción: desastres naturales (terremotos, huracanes, inundaciones, etc), desastres producidos por el hombre (confl ictos sociales, falta de vivienda, etc.) y emergencias complejas (cambio climático, guerras civiles, etc.) La envergadura de la pandemia actual ha afectado directamente la organización social de los ciudadanos y por lo tanto la arquitectura y urbanismo deben contribuir a estudiar esta emergencia humanitaria y ayudar a mitigar los efectos de las próximas pandemias. Por otra parte, no podemos olvidar que todo en nuestro planeta está interconectado, por lo cual el estudio de esta pandemia debe considerarse en una dimensión global, con conexiones directas a los desafíos globales de nuestro planeta: crisis climática, emergencias humanitarias, neoliberalismo y desigualdad social, entre otras. Este enfoque holístico nos invita a imaginar un nuevo orden social, con un mayor equilibrio entre naturaleza y sociedad, con principios éticos y valores morales renovados. La arquitectura y el urbanismo pueden participar en la construcción de este nuevo orden mundial. Objetivo; aumentar la resiliencia urbana y rural

Enablers and barriers to the construction of motives for learning at the university: The student’s perspective

The massification of higher education and the migration to online formats imply changes that affect the ways that people learn and their motivation for learning. In this sense, the motivational orientation of the student can make a difference in learning. This article aims to describe the enablers and barriers to students’ motivation for learning from the perspective of Chilean University students in the areas of health and education. The study was conducted through virtual group interviews. The analysis was carried out on the participants’ accounts from a constructivist approach to grounded theory. The results showed a valuation of the practical and altruistic motives as a structuring motivational axis. In line with the self-determination theory, the existence of a protected space in the classroom appears as an essential motivational enabler of learning, and virtuality is a critical motivational barrier