Reflections: Two Letters, and two poets

The subject of this paper is the rapport of two epistolary poems of Catullus (poems 50 and 65) to the rendition of earlier poets that follow them (poems 51 and 66) as read through the prism of a Callimachean epigram (34 G.-P. = 2 Pf.). The paper seeks to further not only our understanding of Catullus’s use of Sappho and Callimachus as both artistic models and actual poetic figures of his own work, but to demonstrate how widely the intertextual resonance of one poem, here a sepulchral epigram for a dead poet, can be spread throughout the composition of a later author

La Tragédie chorale : poésie grecque et rituel musical

For any teacher of Greek tragedy, whether in Greek or in English, who has confronted student confusion on the role of the tragic chorus, or has been confronted by an obstinate interrogation on the ‘tragic flaw’, or similar anachronistic approach to Greek tragedy, this new work of a long-established scholar of choral poetry will be an essential help-mate. Claude Calame (C.) brings an approach to the tragic chorus that is at once semantic, ethnopoetic and one of cultural anthropology, to attain..

Multi-wavelength Observations of Dusty Star Formation at Low and High Redshift

This paper examines what can be learned about high-redshift star formation from the small fraction of high-redshift galaxies' luminosities that is emitted at accessible wavelengths. We review and quantify empirical correlations between bolometric luminosities produced by star formation and the UV, mid-IR, sub-mm, and radio luminosities of galaxies in the local universe. These correlations suggest that observations of high-redshift galaxies at any of these wavelengths should constrain their star-formation rates to within 0.2--0.3 dex. We assemble the limited evidence that high-redshift galaxies obey these locally calibrated correlations. The characteristic luminosities and dust obscurations of galaxies at z ~ 0, z ~ 1, and z ~ 3 are reviewed. After discussing the relationship between the high-redshift populations selected in surveys at different wavelengths, we calculate the contribution to the 850um background from each. The available data show that a correlation between star-formation rate and dust obscuration L_dust/L_UV exists at low and high redshift. This correlation plays a central role in the major conclusion of this paper: most star formation at high redshift occurred in galaxies with 1 < L_dust/L_UV < 100 similar to those that host the majority of star formation in the local universe and to those that are detected in UV-selected surveys. (abridged)Comment: Scheduled for publication in ApJ v544 Dec 2000. Significant changes to section 4. Characteristic UV and dust luminosities of star-forming galaxies at redshifts z~0, z~1, and z~3 presented. Existence of extremely obscured galaxies more clearly acknowledged. Original conclusions reinforced by the observed correlation between bolometric luminosity and dust obscuration at 0<z<

Massive Star Formation in Galaxies: Radiative transfer models of the UV to mm emission of starburst galaxies

We present illustrative models for the UV to millimeter emission of starburst galaxies which are treated as an ensemble of optically thick giant molecular clouds (GMCs) centrally illuminated by recently formed stars. The models follow the evolution of the GMCs due to the ionization-induced expansion of the HII regions and the evolution of the stellar population within the GMC according to the Bruzual & Charlot stellar population synthesis models. The effect of transiently heated dust grains/PAHs to the radiative transfer, as well as multiple scattering, is taken into account. The expansion of the HII regions and the formation of a narrow neutral shell naturally explains why the emission from PAHs dominates over that from hot dust in the near to mid-IR, an emerging characteristic of the infrared spectra of starburst galaxies. The models allow us to relate the observed properties of a galaxy to its age and star formation history. We find that exponentially decaying 10^7-10^8 yrs old bursts can explain the IRAS colours of starburst galaxies. The models are also shown to account satisfactorily for the multiwavelength data on the prototypical starburst galaxy M82 and NGC6090, a starburst galaxy recently observed by ISO. In M82 we find evidence for two bursts separated by 10^7yrs. In NGC6090 we find that at least part of the far-IR excess may be due to the age of the burst (6.4 x 10^7yrs). We also make predictions about the evolution of the luminosity of starbursts at different wavelengths which indicate that far-IR surveys may preferentially detect older starbursts than mid-IR surveys.Comment: 11 pages; accepted by MNRAS (submitted 9/9/98

Por una condonación de la deuda pública externa de América Latina

Neoliberal globalization exalted the “society of growth”. Growth became the central policy that supposedly would sustain consumption, investment, employment and social well-being.The underlying assumptions of ad infinitum growth had, as a result, “collateral effects” (both human and ecological) but it was assumed that the free market and technological advancements would have a counter effect. And if neither provided a solution, then there would not be any kind at all: progress demanded “sacrifices”.Neoliberal economic theory gave an 180-degree about face:&nbsp; “today’s savings” would no longer be the source for consumption or investment “for tomorrow” (the Keynesian theory). Consumption for the sake of consumption (consumerism) became the motor of growth and productive investment fell in terms of increasing “productive capability” in order to be considered almost exclusively in terms of its profitability in the short run. Between 1970 and 2007, this was interpreted as normal hiccup in the frenzy of “irrational exuberance”.Unbridled consumption and financial investments were strongly directed towards credit: to homes, businesses and Government-States, dismantling, as well, the policies of State well-being. Something was generated, namely, the addictive dependence between economic growth (the accumulation of capital) and limitless debt. * This op-ed has been published by Franz Hinkelammert (Germany-Costa Rica), Orlando Delgado (Mexico), Yamandú Acosta (Uruguay), Henry Mora (Costa Rica), William Hughes (Panama) and Jorge Zúñiga M. (México) in different print media and sites on the web throughout Latin America.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; La globalización neoliberal encumbró la “sociedad del crecimiento”. El crecimiento se convirtió en la política central que supuestamente sostendría el consumo, la inversión, el empleo y el bienestar social.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; El pretendido crecimiento ad infinitum resultó tener “efectos colaterales” (humanos y ecológicos), pero se asumió que el libre mercado y el desarrollo tecnológico lograrían contrarrestarlos. Y si no lograban solucionarlos, entonces no habría solución alguna: el progreso demanda “sacrificios”.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; La teoría económica neoliberal dio un viraje de 180 grados: el “ahorro de hoy” dejo de ser la fuente para el consumo y la inversión “de mañana” (tesis keynesiana). El consumo por el consumo (consumismo) se convirtió en el motor del crecimiento, y la inversión productiva perdió el sentido de incrementar la “capacidad productiva” para considerarse casi exclusivamente en términos de su rentabilidad de corto plazo. Entre 1970 y 2007 se impusieron el capitalismo de casino y la financiarización, dominando la economía real. La crisis del 2008 fue interpretada como un tropezón normal en el frenesí de “exuberancia irracional”.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; El consumismo desenfrenado y la inversión financiera se apuntalaron fuertemente en el crédito: a los hogares, empresas y Estados; desmantelando, además, las políticas del Estado de bienestar. Se generó una dependencia adictiva entre el crecimiento económico (la acumulación de capital) y el endeudamiento sin límite. * Este artículo fue publicado por Franz Hinkelammert (Alemania – Costa Rica) , Orlando Delgado (México), Yamandú Acosta (Uruguay) , Henry Mora (Costa Rica) , William Hughes (Panamá) &nbsp;y Jorge Zúñiga M. (México) &nbsp;en diferentes medios impresos de América Latina. En Montevideo, fue publicado en “La diaria” en su edición correspondiente al martes 16 de junio de 2020, pp. 11-12. Imagen de portada: Rey de oros / técnica mixta y collage sobre tablex (cm. 122 × 172) / Colección M. Saenz de Eredia; Madrid, Españ

Whole brain white matter histogram analysis of diffusion tensor imaging data detects microstructural damage in mild cognitive impairment and Alzheimer’s disease patients

ABSTRACT Background: Amnestic mild cognitive impairment (MCI) is a transitional stage between normal aging and Alzheimer’s disease (AD). However, the clinical conversion from MCI to AD is unpredictable. Hence, identification of non-invasive biomarkers able to detect early changes induced by dementia is a pressing need. Purpose: To explore the added value of histogram analysis applied to measures derived from diffusion tensor imaging (DTI) for detecting brain tissue differences between AD, MCI and healthy subjects (HS). Study type: Retrospective. Population/subjects: Local cohort (57 AD, 28 MCI, 23 HS), Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort (41 AD, 58 MCI, 41 HS). Field Strength: 3T. Dual echo TSE; FLAIR; MDEFT; IR-SPGR; DTI. Assessment: Normal appearing white matter (NAWM) masks were obtained using the T1-weighted volumes for tissue segmentation and T2-weighted images for removal of hyperintensities/lesions. From DTI images, fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AXD) and radial diffusivity (RD) were obtained. NAWM histograms of FA, MD, AXD and RD were derived and characterized estimating: peak height, peak location, mean value (MV), and quartiles (C25, C50, C75), which were compared between groups. Receiver operating characteristic (ROC) and area under ROC curves (AUC) were calculated. To confirm our results, the same analysis was repeated on ADNI dataset. Statistical tests: One-way ANOVA, post-hoc Student’s t-test, multi-class ROC analysis. Results: For the local cohort, C25 of AXD had the maximum capability of group discrimination with AUC of 0.80 for “HS vs patients” comparison and 0.74 for “AD vs others” comparison. For ADNI cohort, MV of AXD revealed the maximum group discrimination capability with AUC of 0.75 for “HS vs patients” comparison and 0.75 for “AD vs others” comparison. Data conclusion: AXD of NAWM might be an early marker of microstructural brain tissue changes occurring during AD course and might be useful for assessing disease progression

Methods of Inactivation of SARS-CoV-2 for Downstream Biological Assays

The scientific community has responded to the coronavirus disease 2019 (COVID-19) pandemic by rapidly undertaking research to find effective strategies to reduce the burden of this disease. Encouragingly, researchers from a diverse array of fields are collectively working towards this goal. Research with infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is undertaken in high-containment laboratories; however, it is often desirable to work with samples at lower-containment levels. To facilitate the transfer of infectious samples from high-containment laboratories, we have tested methods commonly used to inactivate virus and prepare the sample for additional experiments. Incubation at 80°C, a range of detergents, Trizol reagents, and UV energies were successful at inactivating a high titer of SARS-CoV-2. Methanol and paraformaldehyde incubation of infected cells also inactivated the virus. These protocols can provide a framework for in-house inactivation of SARS-CoV-2 in other laboratories, ensuring the safe use of samples in lower-containment levels

EX Lupi in quiescence

EX Lup is the prototype of EXors, a subclass of low-mass pre-main sequence stars whose episodic eruptions are attributed to temporarily increased accretion. In quiescence the optical and near-infrared properties of EX Lup cannot be distinguished from those of normal T Tau stars. Here we investigate whether it is the circumstellar disk structure which makes EX Lup an atypical Class II object. During outburst the disk might undergo structural changes. Our characterization of the quiescent disk is intended to serve as a reference to study the physical changes related to one of EX Lupi's strongest known eruptions in 2008 Jan-Sep. We searched the literature for photometric and spectroscopic observations including ground-based, IRAS, ISO and Spitzer data. After constructing the optical-infrared spectral energy distribution (SED), we compared it with the typical SEDs of other young stellar objects and modeled it using the Monte Carlo radiative transfer code RADMC. A mineralogical decomposition of the 10 micron silicate emission feature and also the description of the optical and near-infrared spectra were performed. The SED is in general similar to that of a typical T Tauri star, though above 7 micron EX Lup emits higher flux. The quiescent phase data suggest low level variability in the optical-mid-infrared domain. Integrating the optical and infrared fluxes we derived a bolometric luminosity of 0.7 L_Sun. The 10 micron silicate profile could be fitted by a mixture consisting of amorphous silicates, no crystalline silicates were found. A modestly flaring disk model with a total mass of 0.025 M_Sun and an outer radius of 150 AU was able to reproduce the observed SED. The derived inner radius of 0.2 AU is larger than the sublimation radius, and this inner gap sets EX Lup aside from typical T Tauri stars.Comment: Accepted for publication in Astronomy and Astrophysics, 10 pages, 6 figure

ASTRO-F - The next generation of mid-infrared surveys

We present basic observational strategies for ASTRO-F (also known as the Imaging Infra Red Surveyor (IRIS)) to be launched in 2004 by the Japanese Institute of Space and Astronautical Science (ISAS). We examine 2 survey scenarios, a deep ~1sq.deg. survey reaching sensitivities an order of magnitude below than the deepest surveys performed by ISO in the mid-IR, and a shallow \~18sq.deg mid-infrared (7-25um in 6 bands) covering an area greater than the entire area covered by all ISO mid-IR surveys. Using 2 cosmological models the number of galaxies predicted for each survey is calculated. The first model uses an enhancement of the pure luminosity evolution model of Pearson & Rowan-Robinson while the new models incorporate a strongly evolving ULIG component. For the deep survey, between 20,000-30,000 galaxies should be detected in the shortest wavebands and ~5000 in the longest (25um) band. The shallow survey would be expected to detect of the order of 100,000 - 150,000 sources.Comment: 17 pages, 13 figures, accepted by MNRA

A fast and accurate method for computing the Sunyaev-Zeldovich signal of hot galaxy clusters

New generation ground and space-based CMB experiments have ushered in discoveries of massive galaxy clusters via the Sunyaev-Zeldovich (SZ) effect, providing a new window for studying cluster astrophysics and cosmology. Many of the newly discovered, SZ-selected clusters contain hot intracluster plasma (kTe > 10 keV) and exhibit disturbed morphology, indicative of frequent mergers with large peculiar velocity (v > 1000 km s^{-1}). It is well-known that for the interpretation of the SZ signal from hot, moving galaxy clusters, relativistic corrections must be taken into account, and in this work, we present a fast and accurate method for computing these effects. Our approach is based on an alternative derivation of the Boltzmann collision term which provides new physical insight into the sources of different kinematic corrections in the scattering problem. This allows us to obtain a clean separation of kinematic and scattering terms which differs from previous works. We briefly mention additional complications connected with kinematic effects that should be considered when interpreting future SZ data for individual clusters. One of the main outcomes of this work is SZpack, a numerical library which allows very fast and precise (<~0.001% at frequencies h nu <~ 20kT_g) computation of the SZ signals up to high electron temperature (kT_e ~ 25 keV) and large peculiar velocity (v/c ~ 0.01). The accuracy is well beyond the current and future precision of SZ observations and practically eliminates uncertainties related to more expensive numerical evaluation of the Boltzmann collision term. Our new approach should therefore be useful for analyzing future high-resolution, multi-frequency SZ observations as well as computing the predicted SZ effect signals from numerical simulations.Comment: 20 pages, 11 figures, 3 tables, accepted by MNRAS; SZpack download: www.Chluba.de/SZpac