Little change in the sizes of the most massive galaxies since z = 1

Recent reports suggest that elliptical galaxies have increased their size dramatically over the last ~8 Gyr. This result points to a major re-think of the processes dominating the latetime evolution of galaxies. In this paper we present the first estimates for the scale sizes of brightest cluster galaxies (BCGs) in the redshift range 0.8 < z < 1.3 from an analysis of deep Hubble Space Telescope imaging, comparing to a well matched local sample taken from the Local Cluster Substructure Survey at z ~ 0.2. For a small sample of 5 high redshift BCGs we measure half-light radii ranging from 14 - 53 kpc using de Vaucuoleurs profile fits, with an average determined from stacking of 32.1 \pm 2.5 kpc compared to a value 43.2 \pm 1.0 kpc for the low redshift comparison sample. This implies that the scale sizes of BCGs at z = 1 are ~ 30% smaller than at z = 0.25. Analyses comparing either Sersic or Petrosian radii also indicate little or no evolution between the two samples. The detection of only modest evolution at most out to z = 1 argues against BCGs having undergone the large increase in size reported for massive galaxies since z = 2 and in fact the scale-size evolution of BCGs appears closer to that reported for radio galaxies over a similar epoch. We conclude that this lack of size evolution, particularly when coupled with recent results on the lack of BCG stellar mass evolution, demonstrates that major merging is not an important process in the late time evolution of these systems. The homogeneity and maturity of BCGs at z = 1 continues to challenge galaxy evolution models.Comment: Accepted for publication in MNRA

Cluster galaxies in XMMU J2235-2557: galaxy population properties in most massive environments at z~1.4

We present a multi-wavelength study of galaxy populations in the core of the massive, X-ray luminous cluster XMMU J2235 at z=1.39, based on VLT and HST optical and near-infrared photometry. Luminosity functions in the z, H, and Ks bands show a faint-end slope consistent with being flat, and a characteristic magnitude M* close to passive evolution predictions of M* of local massive clusters, with a formation redshift z>2. The color-magnitude and color-mass diagrams show evidence of a tight red sequence of massive galaxies, with overall old stellar populations, generally early-type morphology, typically showing early-type spectral features and rest-frame far-UV emission consistent with very low star formation rates (SFR<0.2Msun/yr). Star forming spectroscopic members, with SFRs of up to ~100Msun/yr, are all located at clustercentric distances >~250kpc, with the central cluster region already appearing effectively quenched. Massive galaxies in the core of this cluster appear to be in an advanced evolutionary stage in terms of both star formation and mass assembly. The high-mass end of the galaxy stellar mass function is essentially already in place, and the stellar mass fraction estimated within r500 (~1%, Kroupa IMF) is already similar to that of local massive clusters. On the other hand, morphological analysis of the massive red sequence galaxies suggests that they are smaller than similarly massive local early-types. While possibly affected by systematics and biases, this result might imply that, in spite of the overall early assembly of these sources, their evolution is not complete, and processes like minor (and likely dry) merging might still shape their structural properties to resemble those of their local counterparts, without substantially affecting their stellar mass or host stellar populations.[abridged]Comment: 14 pages, 9 figures, accepted for publication in Astronomy & Astrophysic

Seasonality in reproduction and reproductive physiology of Caviomorphs

1. Animals experience seasonal fluctuations of photoperiod, food availability, temperature and precipitation. This affects their energy budget, often leading to seasonal reproduction.2. We review available literature and (re)-analyse existing datasets on seasonal reproduction of South American caviomorph rodents that are characterised by long pregnancies, typically precocial young and short lactation.3. While births occur nearly year-round in many species, reproductive investment and reproductive output (litter size, offspring mass and growth) vary seasonally, with largest litters often occurring in spring/summer. Male, as well as female, reproductive physiology varies across seasons in most of the investigated species. Experimental studies manipulating environmental aspects that usually change seasonally (photoperiod, nutrition, density) indicate a slightly different mechanistic basis driving seasonal reproduction in caviomorphs than in rodents of the Northern Hemisphere.4. Caviomorphs are a key component of various ecosystems and knowledge of their reproduction and how it might be influenced by climate change (i.e., mean and variance of temperature and rainfall) is urgently needed to predict future population trends

Propuesta didáctica de enseñanza de física por experimentación: desarrollo de actividad práctica agronómica en entorno virtual

Conclusiones Dado el escenario de aislamiento social que debió asumirse frente a la pandemia, tanto docentes como alumnos cambiamos nuestros entornos de desempeño de tareas habituales. La propuesta de hacer un experimento con materiales accesibles en el hogar o en la cercanía de donde residieran los estudiantes fue una instrumentación didáctica para que pudieran hacer una trasposición de los conceptos teórico prácticos planteados desde la virtualidad a situaciones del mundo real, concreto y palpable.En este trabajo se presenta una estrategia didáctica utilizada en la asignatura Física I (primer año de las carreras Ingeniería Agronómica, Ingeniería Zootecnista y Licenciatura en Agroalimentos) que fue desarrollada de manera virtual durante el año 2020. El objetivo de dicha estrategia es que los alumnos integren los conocimientos adquiridos para resolver una situación práctica. Se plantea una actividad práctica para evaluar la consistencia de suelo con posibilidad de desarrollarse en el Campo Escuela de la Facultad de Ciencias Agropecuarias (UNC) o bien, en los domicilios de los alumnos empleando materiales de uso cotidiano. La tarea práctica fue desarrollada en tres etapas, con el acompañamiento de las docentes mediante las consultas a través del aula virtual. Al ser una actividad planteada con consignas abiertas, cada uno tuvo que organizar su trabajo e identificar los puntos importantes a informar; esto les permitió desarrollar su ingenio y creatividad. Mediante esta actividad alcanzó la promoción más del 40% de los alumnos. Las devoluciones de los alumnos evidencian que esta actividad les ayudó a comprender cómo se relaciona la Física con el ámbito de la Agronomía.publishedVersionFil: Valentinuzzi, María Cecilia. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Ingeniería y Mecanización Rural. Cátedra de Física; Argentina.Fil: Valentinuzzi, María Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física "Enrique Gaviola"; Argentina.Fil: Sbarato, V. M. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias. Departamento de Ingeniería y Mecanización Rural. Cátedra de Física; Argentina

Modelling of the effect of ELMs on fuel retention at the bulk W divertor of JET

Effect of ELMs on fuel retention at the bulk W target of JET ITER-Like Wall was studied with multi-scale calculations. Plasma input parameters were taken from ELMy H-mode plasma experiment. The energetic intra-ELM fuel particles get implanted and create near-surface defects up to depths of few tens of nm, which act as the main fuel trapping sites during ELMs. Clustering of implantation-induced vacancies were found to take place. The incoming flux of inter-ELM plasma particles increases the different filling levels of trapped fuel in defects. The temperature increase of the W target during the pulse increases the fuel detrapping rate. The inter-ELM fuel particle flux refills the partially emptied trapping sites and fills new sites. This leads to a competing effect on the retention and release rates of the implanted particles. At high temperatures the main retention appeared in larger vacancy clusters due to increased clustering rate

Nutraceutical Profiles of Two Hydroponically Grown Sweet Basil Cultivars as Affected by the Composition of the Nutrient Solution and the Inoculation With Azospirillum brasilense

Sweet basil (Ocimum basilicum L.) is one of the most produced aromatic herbs in the world, exploiting hydroponic systems. It has been widely assessed that macronutrients, like nitrogen (N) and sulfur (S), can strongly affect the organoleptic qualities of agricultural products, thus influencing their nutraceutical value. In addition, plant-growth-promoting rhizobacteria (PGPR) have been shown to affect plant growth and quality. Azospirillum brasilense is a PGPR able to colonize the root system of different crops, promoting their growth and development and influencing the acquisition of mineral nutrients. On the bases of these observations, we aimed at investigating the impact of both mineral nutrients supply and rhizobacteria inoculation on the nutraceutical value on two different sweet basil varieties, i.e., Genovese and Red Rubin. To these objectives, basil plants have been grown in hydroponics, with nutrient solutions fortified for the concentration of either S or N, supplied as SO42\u2013 or NO3\u2013, respectively. In addition, plants were either non-inoculated or inoculated with A. brasilense. At harvest, basil plants were assessed for the yield and the nutraceutical properties of the edible parts. The cultivation of basil plants in the fortified nutrient solutions showed a general increasing trend in the accumulation of the fresh biomass, albeit the inoculation with A. brasilense did not further promote the growth. The metabolomic analyses disclosed a strong effect of treatments on the differential accumulation of metabolites in basil leaves, producing the modulation of more than 400 compounds belonging to the secondary metabolism, as phenylpropanoids, isoprenoids, alkaloids, several flavonoids, and terpenoids. The primary metabolism that resulted was also influenced by the treatments showing changes in the fatty acid, carbohydrates, and amino acids metabolism. The amino acid analysis revealed that the treatments induced an increase in arginine (Arg) content in the leaves, which has been shown to have beneficial effects on human health. In conclusion, between the two cultivars studied, Red Rubin displayed the most positive effect in terms of nutritional value, which was further enhanced following A. brasilense inoculation

Rapid Changes in the Light/Dark Cycle Disrupt Memory of Conditioned Fear in Mice

Background: Circadian rhythms govern many aspects of physiology and behavior including cognitive processes. Components of neural circuits involved in learning and memory, e.g., the amygdala and the hippocampus, exhibit circadian rhythms in gene expression and signaling pathways. The functional significance of these rhythms is still not understood. In the present study, we sought to determine the impact of transiently disrupting the circadian system by shifting the light/ dark (LD) cycle. Such ‘‘jet lag’ ’ treatments alter daily rhythms of gene expression that underlie circadian oscillations as well as disrupt the synchrony between the multiple oscillators found within the body. Methodology/Principal Findings: We subjected adult male C57Bl/6 mice to a contextual fear conditioning protocol either before or after acute phase shifts of the LD cycle. As part of this study, we examined the impact of phase advances and phase delays, and the effects of different magnitudes of phase shifts. Under all conditions tested, we found that recall of fear conditioned behavior was specifically affected by the jet lag. We found that phase shifts potentiated the stress-evoked corticosterone response without altering baseline levels of this hormone. The jet lag treatment did not result in overall sleep deprivation, but altered the temporal distribution of sleep. Finally, we found that prior experience of jet lag helps to compensate for the reduced recall due to acute phase shifts. Conclusions/Significance: Acute changes to the LD cycle affect the recall of fear-conditioned behavior. This suggests that

Enhanced Fear Expression in a Psychopathological Mouse Model of Trait Anxiety: Pharmacological Interventions

The propensity to develop an anxiety disorder is thought to be determined by genetic and environmental factors. Here we investigated the relationship between a genetic predisposition to trait anxiety and experience-based learned fear in a psychopathological mouse model. Male CD-1 mice selectively bred for either high (HAB), or normal (NAB) anxiety-related behaviour on the elevated plus maze were subjected to classical fear conditioning. During conditioning both mouse lines showed increased fear responses as assessed by freezing behaviour. However, 24 h later, HAB mice displayed more pronounced conditioned responses to both a contextual or cued stimulus when compared with NAB mice. Interestingly, 6 h and already 1 h after fear conditioning, freezing levels were high in HAB mice but not in NAB mice. These results suggest that trait anxiety determines stronger fear memory and/or a weaker ability to inhibit fear responses in the HAB line. The enhanced fear response of HAB mice was attenuated by treatment with either the α2,3,5-subunit selective benzodiazepine partial agonist L-838,417, corticosterone or the selective neurokinin-1 receptor antagonist L-822,429. Overall, the HAB mouse line may represent an interesting model (i) for identifying biological factors underlying misguided conditioned fear responses and (ii) for studying novel anxiolytic pharmacotherapies for patients with fear-associated disorders, including post-traumatic stress disorder and phobias