Undecidability as solution to the problem of measurement: fundamental criterion for the production of events

In recent papers we put forth a new interpretation of quantum mechanics, colloquially known as ``the Montevideo interpretation''. This interpretation is based on taking into account fundamental limits that gravity imposes on the measurement process. As a consequence one has that situations develop where a reduction process is undecidable from an evolution operator. When such a situation is achieved, an event has taken place. In this paper we sharpen the definition of when and how events occur, more precisely we give sufficient conditions for the occurrence of events. We probe the new definition in an example. In particular we show that the concept of undecidability used is not ``FAPP'' (for all practical purposes), but fundamental.Comment: 10 pages, contributed to the Castagnino Festschrif

A realist interpretation of quantum mechanics based on undecidability due to gravity

We summarize several recent developments suggesting that solving the problem of time in quantum gravity leads to a solution of the measurement problem in quantum mechanics. This approach has been informally called "the Montevideo interpretation". In particular we discuss why definitions in this approach are not "for all practical purposes" (fapp) and how the problem of outcomes is resolved.Comment: 7 pages, IOPAMS style, no figures, contributed to the proceedings of DICE 2010, Castiglioncello, slightly improved versio

Modelización y análisis energético de una planta para producción de potencia y refrigeración basada en una mezcla binaria con accionamiento solar

Se presenta la optimización de las temperaturas de operación y la producción de potencia mecánica y de refrigeración para una planta basada en una mezcla de amoníaco y agua, bajo las condiciones ambientales del nordeste argentino. Los balances de energía y materia para el ciclo en conjunto con las ecuaciones de la geometría solar, los datos de fábrica de colectores de tubos al vacio y los datos meteorológicos de Resistencia constituyen un sistema de ecuaciones que se resolvió con un software que incorpora correlaciones de las propiedades termofísicas de la mezcla. Al aumentar la temperatura de sobrecalentamiento se incrementó la potencia mecánica y disminuyó la frigorífica. El rendimiento exergético aumentó hasta cerca del 67% mientras el térmico y la relación de trabajo disminuyeron. Se determinó la producción horaria de potencia mecánica y de refrigeración para días típicos de los meses de verano y de invierno.The optimization of the operating temperatures together with mechanical and refrigeration power generation are presented for a power plant based on an ammonia and water mixture cycle, working under environmental conditions of northeast Argentina. The mass and energy balances for the cycle, together with solar geometry equations, manufacturer data of the vacuum tube collector and meteorological data from the city of Resistencia, constitute an equation system that was solved using software that includes built-in correlations of the termophysical properties of the ammonia and water mixture. By increasing the overheating temperature before the turbine inlet, resulted in a higher mechanical power but a lower cooling power. The exergetic efficiency was increased up to close to 67% while the thermal efficiency and the work ratio were lowered. The mechanical and cooling power generation was determined for days typical of summer and winter of Resistencia.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Efecto de la liofilización en la retención de antocianinas de los frutos de calafate (Berberis microphylla G. Forst.) y su incorporación en cerveza

Los frutos de calafate son extremadamente ricos en compuestos antioxidantes, principalmente antocianinas. El objetivo fue evaluar la influencia de la liofilización sobre el contenido de antocianinas en los calafates durante el almacenamiento. Un grupo de frutos fue analizado inmediatamente y los restantes fueron sometidos a congelado a -80 ºC y liofilización. Por otra parte, a cerveza comercial tipo block se le adicionó 1,0; 2,5; 5,0 o 20 g L-1 de frutos liofilizados y pulverizados. Los frutos frescos tuvieron 35 mg g-1 de antocianinas y la liofilización redujo su contenido en 7 %. El contenido de antocianinas se mantuvo sin variaciones por 21 y 45 días respectivamente. Hacia los 60 días el contenido de antocianinas de los frutos liofilizados representó el 67% del contenido inicial. El pH de la cerveza fue de 4,34 y no varió con el agregado de polvo de calafate hasta 5 g L-1. En el caso de las cervezas con el agregado de 20 g L-1 el pH descendió a 4,00. El agregado de calafate provocó un cambio en el color de la cerveza debido a su aporte de antocianinas, y este cambio en el color fue función de la cantidad de fruto adicionado. La absorbancia a 520 nm fue de 0,230; 0,254; 0,291; 0,353 y 0,644 para la cerveza sin agregado o con 1,0; 2,5; 5,0 o 20 g L-1 de calafate  espectivamente. Solo cantidades mayores a 2,5 g L-1 de polvo adicionado provocaron un incremento de actividad antioxidante, llegando al 30 % con la adición de 20 g L-1. La liofilización es una estrategia adecuada para preservar las antocianinas de los frutos de calafate sin alteraciones por 45 días. Dependiendo de la cantidad adicionada, el calafate provoca en la cerveza cambio de color y descenso del pH que puede ser de utilidad en cervezas especiales

Intoxicación accidental por paraíso (Melia azedarach) en bovinos

Fazzio, L.E.; Costa, E.F.; Streitenberger, N.; Pintos, M.E.; Quiroga, M.A.: Intoxicación accidental por paraíso (Melia azedarach) en bovinos. Rev. vet. 26: 1, 54-58, 201

Lyman break and UV-selected galaxies at z ~ 1: II. PACS-100um/160um FIR detections

We report the PACS-100um/160um detections of a sample of 42 GALEX-selected and FIR-detected Lyman break galaxies (LBGs) at z ~ 1 located in the COSMOS field and analyze their ultra-violet (UV) to far-infrared (FIR) properties. The detection of these LBGs in the FIR indicates that they have a dust content high enough so that its emission can be directly detected. According to a spectral energy distribution (SED) fitting with stellar population templates to their UV-to-near-IR observed photometry, PACS-detected LBGs tend to be bigger, more massive, dustier, redder in the UV continuum, and UV-brighter than PACS-undetected LBGs. PACS-detected LBGs at z ~ 1 are mostly disk-like galaxies and are located over the green-valley and red sequence of the color-magnitude diagram of galaxies at their redshift. By using their UV and IR emission, we find that PACS-detected LBGs tend to be less dusty and have slightly higher total star-formation rates (SFRs) than other PACS-detected UV-selected galaxies within their same redshift range. As a consequence of the selection effect due to the depth of the FIR observations employed, all our PACS-detected LBGs are LIRGs. However, none of them are in the ULIRG regime, where the FIR observations are complete. The finding of ULIRGs-LBGs at higher redshifts suggests an evolution of the FIR emission of LBGs with cosmic time. In an IRX-$\beta$ diagram, PACS-detected LBGs at z ~ 1 tend to be located around the relation for local starburst similarly to other UV-selected PACS-detected galaxies at their same redshift. Consequently, the dust-correction factors obtained with their UV continuum slope allow to determine their total SFR, unlike at higher redshifts. However, the dust attenuation derived from UV to NIR SED fitting overestimates the total SFR for most of our PACS-detected LBGs in age-dependent way: the overestimation factor is higher in younger galaxies.Comment: Accepted for publication in MNRA

Physical properties of Lyman-alpha emitters at z∼0.3z\sim 0.3 from UV-to-FIR measurements

The analysis of the physical properties of low-redshift Ly$\alpha$ emitters (LAEs) can provide clues in the study of their high-redshift analogues. At $z \sim 0.3$, LAEs are bright enough to be detected over almost the entire electromagnetic spectrum and it is possible to carry out a more precise and complete study than at higher redshifts. In this study, we examine the UV and IR emission, dust attenuation, SFR and morphology of a sample of 23 GALEX-discovered star-forming (SF) LAEs at $z \sim 0.3$ with direct UV (GALEX), optical (ACS) and FIR (PACS and MIPS) data. Using the same UV and IR limiting luminosities, we find that LAEs at $z\sim 0.3$ tend to be less dusty, have slightly higher total SFRs, have bluer UV continuum slopes, and are much smaller than other galaxies that do not exhibit Ly$\alpha$ emission in their spectrum (non-LAEs). These results suggest that at $z \sim 0.3$ Ly$\alpha$ photons tend to escape from small galaxies with low dust attenuation. Regarding their morphology, LAEs belong to Irr/merger classes, unlike non-LAEs. Size and morphology represent the most noticeable difference between LAEs and non-LAEs at $z \sim 0.3$. Furthermore, the comparison of our results with those obtained at higher redshifts indicates that either the Ly$\alpha$ technique picks up different kind of galaxies at different redshifts or that the physical properties of LAEs are evolving with redshift.Comment: Accepted for publication in Ap

PACS-Herschel FIR detections of Lyman-alpha emitters at 2.0<z<3.5

In this work we analyze the physical properties of a sample of 56 spectroscopically selected star-forming (SF) Ly$\alpha$ emitting galaxies at 2.0$\lesssim$z$\lesssim$3.5 using both a spectral energy distribution (SED) fitting procedure from rest-frame UV to mid-IR and direct 160$\mu$m observations taken with the Photodetector Array Camera & Spectrometer (PACS) instrument onboard \emph{Herschel Space Observatory}. We define LAEs as those Ly$\alpha$ emitting galaxies whose rest-frame Ly$\alpha$ equivalent widths (Ly$\alpha$ EW$_{rest-frame}$) are above 20\AA, the typical threshold in narrow-band searches. Ly$\alpha$ emitting galaxies with Ly$\alpha$ EW$_{rest-frame}$ are called non-LAEs. As a result of an individual SED fitting for each object, we find that the studied sample of LAEs contains galaxies with ages mostly below 100Myr and a wide variety of dust attenuations, SFRs, and stellar masses. The heterogeneity in the physical properties is also seen in the morphology, ranging from bulge-like galaxies to highly clumpy systems. In this way, we find that LAEs at 2.0$\lesssim$z$\lesssim$3.5 are very diverse, and do not have a bimodal nature, as suggested in previous works. Furthermore, the main difference between LAEs and non-LAEs is their dust attenuation, because LAEs are not as dusty as non-LAEs. On the FIR side, four galaxies of the sample (two LAEs and two non-LAEs) have PACS-FIR counterparts. Their total IR luminosity place all of them in the ULIRG regime and are all dusty objects, with A$_{1200}$$\gtrsim$4mag. This is an indication from direct FIR measurements that dust and Ly$\alpha$ emission are not mutually exclusive. This population of red and dusty LAEs is not seen at z$\sim$0.3, suggesting an evolution with redshift of the IR nature of galaxies selected via their Ly$\alpha$ emission.Comment: Accepted for publication in A&