Reheating constraints and consistency relations of the Starobinsky model and some of its generalizations

Building on the success of the Starobinsky model in describing the inflationary period of the universe, we investigate two simple generalizations of this model and their constraints imposed by the reheating epoch. The first generalization takes the form $R^{2p}$, while the second is the $\alpha$-Starobinsky model. We first focus on the case where $p=1$ or equivalently, $\alpha=1$, which corresponds to the original Starobinsky model. We derive exact consistency relations between observables and cosmological quantities, without neglecting any terms, and impose the reheating condition $0 < \omega_{re} < 0.25$, where $\omega_{re}$ is the equation of state parameter at the end of reheating. This allows us to obtain new bounds for $n_s$ and $r$ that satisfy this condition and apply them to other observables and cosmological quantities. We repeat this process for the cases where $p \neq 1$ and $\alpha \neq 1$ and find that these generalizations only result in minor modifications of the Starobinsky model, including the potential and the bounds on observables and cosmological quantities.Comment: 17 pages, 2 figure

The role of environment in the morphological transformation of galaxies in 9 intermediate redshift clusters

[abridged] We analyze a sample of 9 massive clusters at 0.4<z<0.6 observed with MegaCam in 4 photometric bands (g,r,i,z) from the core to a radius of 5 Mpc (~4000 galaxies). Galaxy cluster candidates are selected using photometric redshifts computed with HyperZ. Morphologies are estimated with galSVM in two broad morphological types (early-type and late-type). We examine the morphological composition of the red-sequence and the blue-cloud and study the relations between galaxies and their environment through the morphology-density relations (T-Sigma) and the morphology-radius relation (T-R) in a mass limited sample (log(M/Msol)>9.5). We find that the red sequence is already in place at z~0.5 and it is mainly composed of very massive (log(M/Msol)>11.3) early-type galaxies. These massive galaxies seem to be already formed when they enter the cluster, probably in infalling groups, since the fraction remains constant with the cluster radius. Their presence in the cluster center could be explained by a segregation effect reflecting an early assembly history. Any evolution that takes place in the galaxy cluster population occurs therefore at lower masses (10.3<log(M/Msol)<11.3). For these galaxies, the evolution, is mainly driven by galaxy-galaxy interactions in the outskirts as revealed by the T-Sigma relation. Finally, the majority of less massive galaxies (9.5<log(M/Msol)<10.3) are late-type galaxies at all locations, suggesting that they have not started the morphological transformation yet even if this low mass bin might be affected by incompleteness.Comment: A&A in pres

Electrochemical Impedance Spectroscopy (EIS): A Review Study of Basic Aspects of the Corrosion Mechanism Applied to Steels

AC impedance measurements have been applied for over twenty years in electrochemistry and physics to investigate the electrical properties of conductive materials and their interfaces using an external electrical impulse (VOLTAGE, V or CURRENT, I) as driving force. Furthermore, its application has recently appeared to be destined in the Biotechnology field as an effective tool for rapid microbiologic diagnosis of living organism in situ. However, there is no doubt that the electrochemical impedance spectroscopy (EIS) is still one of the most useful techniques around the world for metal corrosion control and its monitoring. Corrosion has long been recognized as one of the most expensive stumbling blocks that concern many industries and government agencies, because it is a steel destructive phenomenon that occurs due to the chemical interaction with aqueous environments and takes place at the interface between metal and electrolyte producing an electrical charge transfer or ion diffusion process. Consequently, it is experimentally possible to determine through the EIS technique the mechanism and control that kinectics of corrosion reactions encounter. First, EIS data is collected through a potentiostat/ galvanostat apparatus. After, it is fitted to a mathematical model (i.e. an equivalent electrical circuit, EEC) for its interpretation and analysis, fundamentally seeking a meaningful physical interpretation. Finally, this review reports some basic aspects of the corrosion mechanism applied to steels through the experimental EIS response using Nyquist or Bode plots. Examples are given for different applied electrochemical impedance cases in which steel is under study intentionally exposed to a corrosive aqueous solution by applying a sinusoidal potential at various test conditions

A Wide-Field Study of the z~0.8 Cluster RX J0152.7-1357: the Role of Environment in the Formation of the Red-Sequence

[ABRIDGED] We present the first results from the largest spectroscopic survey to date of an intermediate redshift galaxy cluster, the z=0.834 cluster RX J0152.7-1357. We use the colors of galaxies, assembled from a D~12 Mpc region centered on the cluster, to investigate the properties of the red-sequence as a function of density and clustercentric radius. Our wide-field multi-slit survey with a low-dispersion prism in the IMACS spectrograph at Magellan allowed us to identify 475 new members of the cluster and its surrounding large scale structure with a redshift accuracy of dz/(1+z)~1% and a contamination rate of ~2% for galaxies with i<23.75 mag. We combine these new members with the 279 previously known spectroscopic members to give a total of 754 galaxies from which we obtain a mass-limited sample of 300 galaxies with stellar masses M>4x10^{10} M_sun. We find that the red galaxy fraction is 93+/-3% in the two merging cores of the cluster and declines to a level of 64+/-3% at projected clustercentric radii R>~3 Mpc. At these large projected distances, the correlation between clustercentric radius and local density is nonexistent. This allows an assessment of the influence of the local environment on galaxy evolution, as opposed to mechanisms that operate on cluster scales. Even beyond R>3 Mpc we find an increasing fraction of red galaxies with increasing local density. The red fraction at the highest local densities in two groups at R>3 Mpc matches the red fraction found in the two cores. Strikingly, galaxies at intermediate densities at R>3 Mpc, that are not group members, also show signs of an enhanced red fraction. Our results point to such intermediate density regions and the groups in the outskirts of the cluster, as sites where the local environment influences the transition of galaxies onto the red-sequence.Comment: 15 pages, 10 figures, 1 table, accepted for publication in ApJ, expanded introduction and additional references adde

Methicillin-Resistant Staphylococcus aureus in a Beauty Salon, the Netherlands

An outbreak of community-associated USA300 methicillin-resistant Staphylococcus aureus occurred in a beautician and 2 of her customers. Eight other persons, who were either infected (n = 5) or colonized (n = 3), were linked to this outbreak, including a family member, a household contact, and partners of customers

Evolution of the Early-Type Galaxy Fraction in Clusters since z = 0.8

We study the morphological content of a large sample of high-redshift clusters to determine its dependence on cluster mass and redshift. Quantitative morphologies are based on bulge+disk decompositions of cluster and field galaxies on deep VLT/FORS2 images of 18 optically-selected clusters at 0.45 < z < 0.80 from the ESO Distant Cluster Survey (EDisCS). Morphological content is given by the early-type galaxy fraction f_et, and early-type galaxies are selected based on their bulge fraction and image smoothness. A set of 158 SDSS clusters is analyzed exactly as the EDisCS sample to provide a robust local comparison. Our main results are: (1) f_et values for the SDSS and EDisCS clusters exhibit no clear trend as a function of sigma. (2) Mid-z EDisCS clusters around sigma = 500 km/s have f_et ~= 0.5 whereas high-z EDisCS clusters have f_et ~= 0.4 (~25% increase over 2 Gyrs). (3) There is a marked difference in the morphological content of EDisCS and SDSS clusters. None of the EDisCS clusters have f_et greater than 0.6 whereas half of the SDSS clusters lie above this value. This difference is seen in clusters of all velocity dispersions. (4) There is a strong correlation between morphology and star formation in SDSS and EDisCS clusters. This correlation holds independent of sigma and z even though the fraction of [OII] emitters decreases from z~0.8 to z~0.06 in all environments. Our results pose an interesting challenge to structural transformation and star formation quenching processes that strongly depend on the global cluster environment and suggest that cluster membership may be of lesser importance than other variables in determining galaxy properties. (ABRIDGED)Comment: 22 pages, 10 figures, accepted for publication in A&

Age- and Gender-Related Changes in Contractile Properties of Non-Atrophied EDL Muscle

Background: In humans, ageing causes skeletal muscles to become atrophied, weak, and easily fatigued. In rodent studies, ageing has been associated with significant muscle atrophy and changes in the contractile properties of the muscles. However, it is not entirely clear whether these changes in contractile properties can occur before there is significant atrophy, and whether males and females are affected differently. Methods and Results: We investigated various contractile properties of whole isolated fast-twitch EDL muscles from adult (2–6 months-old) and aged (12–22 months-old) male and female mice. Atrophy was not present in the aged mice. Compared with adult mice, EDL muscles of aged mice had significantly lower specific force, longer tetanus relaxation times, and lower fatiguability. In the properties of absolute force and muscle relaxation times, females were affected by ageing to a greater extent than males. Additionally, EDL muscles from a separate group of male mice were subjected to eccentric contractions of 15 % strain, and larger force deficits were found in aged than in adult mice. Conclusion: Our findings provide further insight into the muscle atrophy, weakness and fatiguability experienced by the elderly. We have shown that even in the absence of muscle atrophy, there are definite alterations in the physiological properties of whole fast-twitch muscle from ageing mice, and for some of these properties the alterations are mor

Epidemiology of community-onset Staphylococcus aureus infections in pediatric patients: an experience at a Children's Hospital in central Illinois

<p>Abstract</p> <p>Background</p> <p>The nation-wide concern over methicillin-resistant <it>Staphylococcus aureus </it>(MRSA) has prompted many clinicians to use vancomycin when approaching patients with suspected staphylococcal infections. We sought to characterize the epidemiology of community-onset <it>S. aureus </it>infections in hospitalized children to assist local clinicians in providing appropriate empiric antimicrobial therapy.</p> <p>Methods</p> <p>From January 2005–June 2008, children (0–18 years old) admitted to the Children's Hospital of Illinois with community-onset <it>S. aureus </it>infections were identified by a computer-assisted laboratory-based surveillance and medical record review.</p> <p>Results</p> <p>Of 199 patients, 67 (34%) had invasive infections, and 132 (66%) had skin and soft tissue infections (SSTIs). Among patients with invasive infections, <it>S. aureus </it>isolates were more likely to be susceptible to methicillin (MSSA 63% vs. MRSA 37%), whereas patients with SSTIs, <it>S. aureus </it>isolates were more likely to be resistant to methicillin (MRSA 64% vs. MSSA 36%). Bacteremia and musculoskeletal infections were the most common invasive infections in both groups of <it>S. aureus</it>. Pneumonia with empyema was more likely to be caused by MRSA (<it>P </it>= 0.02). The majority (~90%) of MRSA isolates were non-multidrug resistant, even in the presence of healthcare-associated risk factors.</p> <p>Conclusion</p> <p>Epidemiological data at the local level is important for antimicrobial decision-making. MSSA remains an important pathogen causing invasive community-onset <it>S. aureus </it>infections among hospitalized children. In our hospital, nafcillin in combination with vancomycin is recommended empiric therapy in critically ill patients with suspected invasive staphylococcal infections. Because up to 25% of MSSA circulating in our area are clindamycin-resistant, clindamycin should be used cautiously as empiric monotherapy in patients with suspected invasive staphylococcal infections.</p

High tide or riptide on the cosmic shoreline? A water-rich atmosphere or stellar contamination for the warm super-Earth GJ 486b from JWST observations

Planets orbiting M-dwarf stars are prime targets in the search for rocky exoplanet atmospheres. The small size of M dwarfs renders their planets exceptional targets for transmission spectroscopy, facilitating atmospheric characterization. However, it remains unknown whether their host stars' highly variable extreme-UV radiation environments allow atmospheres to persist. With JWST, we have begun to determine whether or not the most favorable rocky worlds orbiting M dwarfs have detectable atmospheres. Here, we present a 2.8–5.2 μm JWST NIRSpec/G395H transmission spectrum of the warm (700 K, 40.3× Earth's insolation) super-Earth GJ 486b (1.3 R⊕ and 3.0 M⊕). The measured spectrum from our two transits of GJ 486b deviates from a flat line at 2.2σ − 3.3σ, based on three independent reductions. Through a combination of forward and retrieval models, we determine that GJ 486b either has a water-rich atmosphere (with the most stringent constraint on the retrieved water abundance of H2O > 10% to 2σ) or the transmission spectrum is contaminated by water present in cool unocculted starspots. We also find that the measured stellar spectrum is best fit by a stellar model with cool starspots and hot faculae. While both retrieval scenarios provide equal quality fits (${\chi }_{\nu }^{2}=1.0$) to our NIRSpec/G395H observations, shorter wavelength observations can break this degeneracy and reveal if GJ 486b sustains a water-rich atmosphere

Transfer of SCN1A to the brain of adolescent mouse model of Dravet syndrome improves epileptic, motor, and behavioral manifestations

Dravet syndrome is a genetic encephalopathy characterized by severe epilepsy combined with motor, cognitive, and behavioral abnormalities. Current antiepileptic drugs achieve only partial control of seizures and provide little benefit on the patient’s neurological development. In >80% of cases, the disease is caused by haploinsufficiency of the SCN1A gene, which encodes the alpha subunit of the Nav1.1 voltage-gated sodium channel. Novel therapies aim to restore SCN1A expression in order to address all disease manifestations. We provide evidence that a high-capacity adenoviral vector harboring the 6-kb SCN1A cDNA is feasible and able to express functional Nav1.1 in neurons. In vivo, the best biodistribution was observed after intracerebral injection in basal ganglia, cerebellum, and prefrontal cortex. SCN1A A1783V knockin mice received the vector at 5 weeks of age, when most neurological alterations were present. Animals were protected from sudden death, and the epileptic phenotype was attenuated. Improvement of motor performance and interaction with the environment was observed. In contrast, hyperactivity persisted, and the impact on cognitive tests was variable (success in novel object recognition and failure in Morris water maze tests). These results provide proof of concept for gene supplementation in Dravet syndrome and indicate new directions for improvement