La teoría cinética de la materia. Entre los límites clásicos y el nacimiento de la física cuántica

En su devenir histórico, la idea de energía fue resistida en muchas ocasiones y de diversas formas, y actualmente en nuestra manera de pensar, sigue latente la idea de un fluido sutil que se esconde dentro los cuerpos materiales. A lo largo del siglo XIX, la incorporación de la idea energía comienza teniendo un significado vago y reducido en la mecánica newtoniana. Hacerlo preciso y amplio, hasta ser utilizado en los problemas relacionados con el calor y en general en la termodinámica, ha costado a los científicos una extraordinaria labor de abstracción al punto de hacer pronunciar al físico Richard Feyman, su célebre frase: "es importante constatar que al día de hoy no sabernos bien que es la energía"

La ciudad de las técnicas modernas

For decades, the so-called modern architecture and urbanism tried to modify the environment by applying new techniques. Le Corbusier was one of its remarkable supporters, and his poetical associations related to the full confidence in the technical era can be found in most part of his work performed during the first decades of the 20th century. This paper analyzes the technological innovations presented in an urban project of the first postwar period by Le Corbusier, Plan Voisin pour Paris, for considering it to be representative of the relation between technique and cultural transformations in the ways of the metropolitan social life.La arquitectura y el urbanismo denominados modernos intentaron durante décadas modificar el ambiente mediante la aplicación denuevas formas técnicas. Contando con partidarios como Le Corbusier, las asociaciones poéticas expresadas por el arquitecto en relación con una confianza plena en la era técnica se pueden observar en gran parte de su obra desarrollada durante las primeras décadas del siglo XX. El presente texto analiza las innovaciones tecnológicas presentes en un proyecto urbano de Le Corbusier de la primera posguerra: el Plan Voisin pour Paris, por considerarlo representativo de las relaciones entre técnica y transformaciones culturales en las formas de vida social metropolitana

Lo rutinario de lo científico y lo fabuloso de lo real. Modernización y naturaleza en el balneario de Rosario de la Frontera (1825-1888)

El surgimiento de pandemias en las crecientes urbanizaciones de la segunda mitad del siglo XIX obligó a cambiar significativamente las políticas sanitarias en la Argentina. Junto con la fiebre amarilla o el cólera, enfermedades venéreas, como sífilis y gonorrea, así como afecciones como neurastenia, histeria o “debilidad nerviosa” adquirieron una marcada presencia en la cultura sanitaria. Dentro del mercado local, comenzaron a proliferar diversas sustancias, como tónicos y aceites vendidos en farmacias, boticas y otros puntos de distribución. Asimismo, se fueron instalando emprendimientos terapéuticos privados, provistos con suministro eléctrico e implementos técnicos, como centros de hidroterapia, electroterapia, gimnasia mecánica, entre otros. Los médicos, junto con los comerciantes, se sumaron al mercado de ofertas de productos y servicios para la sanación de males diversos, que fueron promocionados como objetos de consumo a través de avisos, publicidades en diarios, revistas y otros medios de difusión. A finales de siglo XIX, en Buenos Aires se podía observar una creciente comercialización de una amplia gama de productos vinculados a la salud, que serían promotores tanto de la expansión del mercado interno como de modificaciones en las pautas de consumo. Alimentos, indumentaria, muebles, adornos, bebidas eran despachados por una extensa red de negocios y agentes sociales. No obstante, el auge que generó este fenómeno, también surgirían expresiones de descontento y desconfianza, tanto de sectores de la sociedad como del propio gobierno a cargo, que cuestionarían estas prácticas por considerarlas como “curanderismo” o “charlatanismo”.1 Con frecuencia, muchos productos eran comercializados por fuera de los locales habilitados y los servicios eran realizados por no diplomados. Dentro de estos cuestionamientos, las prácticas de hidroterapia tendrían sus detractores

EPBA News. The audiovisual representation of the Estudio del Plan de Buenos Aires (EPBA) as an official means of urban education

En 1949, el cortometraje La ciudad frente al río. Tercera fundación de Buenos Aires fue estrenado en esa ciudad como parte de una campaña oficial de propaganda de “Divulgación urbana y educación” promovida por el Estudio del Plan de Buenos Aires (EPBA), un organismo dependiente de la Municipalidad de la Ciudad de Buenos Aires, para ser exhibido a escala nacional e internacional. Tomando el corto como caso de estudio, este trabajo se propone analizar el uso de representaciones audiovisuales no argumentales como medio de comunicación e intercambio del debate urbano y arquitectónico en el período posterior a la Segunda Guerra Mundial.In 1949, the short film The City Facing the River. Third Foundation of Buenos Aires was released in Buenos Aires as part of an official propaganda campaign of “Urban disclosure and education” promoted by the Estudio del Plan de Buenos Aires (EPBA), a body dependent on the Municipality of the City of Buenos Aires, to be exhibited on a national and international scale. Taking the short film as a case study, this work aims to analyze the use of non-fictional audiovisual representations as a means of communication and exchange of urban and architectural debate in the post-World War II period.Dossier: Medios de comunicación y difusión internacional de la arquitectura de posguerra (1945-1980)Facultad de Arquitectura y Urbanism

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M&gt;70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0&lt;e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Sinceresly yours, Odilia Suárez

A few years after her graduation as an architect, Odilia Suárez traveled to Mexico on behalf of the Revista de Arquitectura of the Central Architects Association (SCA) to attend the VIII Pan-American Congress of Architects of 1952. The trip allowed her to continue with her professional training, but also to visit her older sister Yolanda, who lived in Mexico City. During her stay, Suárez met some Mexican culture personalities and also the architect Frank Lloyd Wright, with whom she would exchange five letters until she could reach his residence “Taliesin West”. Based on the reading of this correspondence, this article seeks to establish links between the personal experiences of Suárez and his professional works, in particular, with the implementation and teaching of the disciplinary field Urban Design, locally translated as Diseño Urbano.Pocos años después de graduarse como arquitecta, Odilia Suárez viajó a México en representación de la Revista de Arquitectura de la Sociedad Central de Arquitectos (SCA), para asistir al VIII Congreso Panamericano de Arquitectos de 1952. El viaje le permitiría continuar con su capacitación profesional y también visitar a su hermana mayor Yolanda, quien vivía en la Ciudad de México. Durante su estadía conoció personalidades de la cultura mexicana y al arquitecto Frank Lloyd Wright, con quien intercambiaría cinco cartas hasta llegar a su residencia “Taliesin West”. A partir de la lectura de esa correspondencia, este artículo busca establecer vinculaciones entre las experiencias personales de Suárez y sus obras profesionales, en particular, con la implementación y enseñanza del campo disciplinar Urban Design, localmente traducido como Diseño Urbano