Reconfigurable photoinduced metamaterials in the microwave regime

We investigate optically reconfigurable dielectric metamaterials at gigahertz frequencies. More precisely, we study the microwave response of a subwavelength grating optically imprinted into a semiconductor slab. In the homogenized regime, we analytically evaluate the ordinary and extraordinary component of the effective permittivity tensor by taking into account the photo-carrier dynamics described by the ambipolar diffusion equation. We analyze the impact of semiconductor parameters on the gigahertz metamaterial response which turns out to be highly reconfigurable by varying the photogenerated grating and which can show a marked anisotropic behavior.Comment: 6 figures, 7 page

Improvement of heart rate recovery after exercise training in older people.

Twenty-four subjects aged 70 and older were retrospectively selected from our archives and screened for symptoms of cardiovascular disease. Baseline exercise test was negative for myocardial ischemia in all subjects. All subjects had completed an 8-week program, performed for a variety of indications and consisting of an aerobic physical training program including 30 minutes of cycling three times per week at 65% to 75% of maximum heart rate achieved at peak exercise test performed at enrollment, an educational intervention, dietary advice, and psychological support. All subjects underwent a cardiopulmonary exercise test (CPX) before and at the end of exercise training. At the end of each CPX, peak oxygen uptake (VO2peak), the rate of increase of ventilation per unit of increase of carbon dioxide production (VE/VCO2slope), and HRR were recorded. Twenty-five healthy subjects younger than 60 with no evidence of exercise-induced myocardial ischemia and not enrolled in any exercise training program were also retrospectively selected from our archives and used as a control group for analyzing HRR. These patients performed two exercise tests several weeks apart. Several studies have shown that changes in vagal tone can be used as an outcome tool that helps identify patients or subjects with or without cardiovascular disease at risk for a cardiovascular event, although the evidence of a prognostic value of HRR in older subjects without cardiovascular disease is rather poor. In this study, exercise training resulted in HRR improvement in healthy elderly subjects, suggesting that exercise training improves vagal/sympathetic balance in older subjects without cardiovascular disease as well. Whether the observed improvement in HRR may have long-term beneficial prognostic effects was not the aim of the study, although a beneficial effect might be postulated, in light of the Framingham dat

Schedule‐Aware Bundle Routing: Analysis and enhancements

The Delay-/Disruption-Tolerant Networking (DTN) architecture was designed to cope with challenges such as long delays and intermittent connectivity. To exploit the a priori knowledge of contacts, typical of space networks, NASA-JPL designed and included in ION (its DTN protocol suite) the Contact Graph Routing (CGR) algorithm. This paper studies the latest version, recently standardized as Schedule-Aware Bundle Routing (SABR) within the Consultative Committee for Space Data Systems (CCSDS). The first part of the paper is devoted to the algorithm analysis, which distinguishes three logical phases to examine sequentially. Following this comprehensive study, three enhancements are proposed, which aim to improve SABR accuracy and resistance against possible loops. They are studied on a simple but challenging DTN topology, implemented on a virtual GNU/Linux testbed. Tests are performed by running the latest version of ION and an independent implementation of SABR developed by the authors, Unibo-CGR. The numerical results are then examined in detail to highlight both SABR mechanisms and the advantages offered by the proposed enhancements

Ranolazine Attenuates Trastuzumab-Induced Heart Dysfunction by Modulating ROS Production

The ErbB2 blocker trastuzumab improves survival in oncologic patients, but can cause cardiotoxicity. The late Na+ current inhibitor ranolazine has been shown to counter experimental HF, including doxorubicin cardiotoxicity (a condition characterized by derangements in redox balance), by lowering the levels of reactive oxygen species (ROS). Since ErbB2 can modulate ROS signaling, we tested whether trastuzumab cardiotoxicity could be blunted by ranolazine via redox-mediated mechanisms. Trastuzumab decreased fractional shortening and ejection fraction in mice, but ranolazine prevented heart dysfunction when co-administered with trastuzumab. Trastuzumab cardiotoxicity was accompanied by elevations in natriuretic peptides and matrix metalloproteinase 2 (MMP2) mRNAs, which were not elevated with co-treatment with ranolazine. Trastuzumab also increased cleavage of caspase-3, indicating activation of the proapoptotic machinery. Again, ranolazine prevented this activation. Interestingly, Neonatal Rat Ventricular Myocytes (NRVMs), labeled with MitoTracker Red and treated with trastuzumab, showed only a small increase in ROS compared to baseline conditions. We then stressed trastuzumab-treated cells with the beta-agonist isoproterenol to increase workload, and we observed a significant increase of probe fluorescence, compared with cells treated with isoproterenol alone, reflecting induction of oxidative stress. These effects were blunted by ranolazine, supporting a role for INa inhibition in the regulation of redox balance also in trastuzumab cardiotoxicity

On the Effective Metric of a Planck Star

Spacetime metrics describing `non-singular' black holes are commonly studied in the literature as effective modification to the Schwarzschild solution that mimic quantum gravity effects removing the central singularity. Here we point out that to be physically plausible, such metrics should also incorporate the 1-loop quantum corrections to the Newton potential and a non-trivial time delay between an observer at infinity and an observer in the regular center. We present a modification of the well-known Hayward metric that features these two properties. We discuss bounds on the maximal time delay imposed by conditions on the curvature, and the consequences for the weak energy condition, in general violated by the large transversal pressures introduced by the time delay.Comment: 10 pages, many figures; v2 added reference

Surgical therapy for ischemic heart failure: Single-center experience with surgical anterior ventricular restoration

ObjectivesOur objectives were (1) to report operative and long-term mortality in patients submitted to anterior surgical ventricular restoration, (2) to report changes in clinical and cardiac status induced by surgical ventricular restoration, and (3) to report predictors of death in a large cohort of patients operated on at San Donato Hospital, Milan, Italy.MethodsA total of 1161 consecutive patients (83% men, 62 ± 10 years) had anterior surgical ventricular restoration with or without coronary artery bypass grafting and with or without mitral repair/replacement. A complete echocardiographic study was performed in 488 of 1161 patients operated on between January 1998 and October 2005 (study group). The indication for surgery was heart failure in 60% of patients, angina, and/or a combination of the two.ResultsThirty-day cardiac mortality was 4.7% (55/1161) in the overall group and 4.9% (24/488) in the study group. Determinants of hospital mortality were mitral valve regurgitation and need for a mitral valve repair/replacement. Mitral regurgitation (>2+) associated with a New York Heart Association class greater than II and with diastolic dysfunction (early-to-late diastolic filling pressure >2) further increases mortality risk. Global systolic function improved postoperatively: ejection fraction improved from 33% ± 9% to 40% ± 10% (P < .001); end-diastolic and end-systolic volumes decreased from 211 ± 73 to 142 ± 50 and 145 ± 64 to 88 ± 40 mL, respectively (P < .001) early after surgery. New York Heart Association functional class improved from 2.7 ± 0.9 to 1.6 ± 0.7 (P < .001) late after surgery. Long-term survival in the overall population was 63% at 120 months.ConclusionsSurgical ventricular restoration for ischemic heart failure reduces ventricular volumes, improves cardiac function and functional status, carries an acceptable operative mortality, and results in good long-term survival. Predictors of operative mortality are mitral regurgitation of 2+ or more, New York Heart Association class greater than II, and diastolic dysfunction (early-to-late diastolic filling pressure >2)

GNSS-based dam monitoring: The application of a statistical approach for time series analysis to a case study

Dams are one of the most important engineering works of the current human society, and it is crucial to monitor and obtain analytical data to log their conditions, predict their behavior and, eventually, receive early warnings for planning interventions and maintenance activities. In this context, GNSS-based point displacement monitoring is nowadays a consolidated technique that is able to provide daily millimeter level accuracy, even with less sophisticated and less expensive single-frequency equipment. If properly designed, daily records of such monitoring systems produce time series that, when long enough, allow for an accurate reconstruction of the geometrical deformation of the structure, thus guiding semi-automatic early warning systems. This paper focuses on the procedure for the GNSS time series processing with a statistical approach. In particular, real-world times series collected from a dam monitoring test case are processed as an example of data filtering. A remove–restore technique based on a collocation approach is applied here. Basically, it consists of an initial deterministic modeling by polynomials and periodical components through least squares adjustment and Fourier transform, respectively, followed by a stochastic modeling based on empirical covariance estimation and a collocation approach. Filtered time series are interpreted by autoregressive models based on environmental factors such as air or water temperature and reservoir water level. Spatial analysis is finally performed by computing correlations between displacements of the monitored points, as well as by visualizing the overall structure deformation in time. Results positively validate the proposed data processing workflow, providing useful hints for the implementation of automatic early warning systems in the framework of structural monitoring based on continuous displacement measurements

Arrecifes coralígenos infralitorales: estructura y variabilidad espacial de las comunidades de macroalgas

Coralligenous reefs are calcareous structures edified mostly by coralline algae that characterize the circalittoral zone of the Mediterranean Sea. However, in some cases coralline algae can constitute peculiar infralittoral biogenic reefs which have been studied less than the circalittoral ones. This study aims to contribute to the knowledge of infralittoral coralligenous reefs by describing their macroalgal assemblages on a large rocky platform off the Tuscany coasts, northwestern Mediterranean Sea. To this end, a multifactorial sampling design was used to describe the structure of the assemblages and to evaluate the variability of the system at multiple spatial scales. A total of 71 macroalgal taxa were found on the coralline algae. Macroalgal assemblages were well structured, with high biodiversity values. The dominant taxa included both photophilous and sciaphilous species, guaranteeing peculiar characteristics in these assemblages, above all if compared with the typical infralittoral and circalittoral macroalgal communities of the same geographic area. The assemblages showed greater variability at a small and intermediate spatial scale than at a large scale. Although infralittoral coralligenous outcrops constitute a peculiar system, they are still poorly understood and should not only be the object of specific studies but also be included in monitoring programmes.Los arrecifes coralígenos son estructuras calcáreas edificadas principalmente por algas coralinas que caracterizan la zona circalitoral del Mar Mediterráneo. Sin embargo, en algunos casos las algas coralinas pueden constituir peculiares arrecifes biogénicos infralitorales menos investigados que los circalitorales. El estudio tiene como objetivo contribuir al conocimiento de los arrecifes coralígenos infralitorales describiendo sus comunidades de macroalgas en una gran plataforma rocosa frente a las costas de Toscana, al noroeste del mar Mediterráneo. Un diseño de muestreo multifactorial fue utilizado para describir la estructura de comunidades algales y evaluar la variabilidad del sistema en múltiples escalas espaciales. Se encontró un total de 71 taxones de macroalgas sobre las algas coralinas. Las comunidades de macroalgas estaban bien estructuradas con altos valores de biodiversidad. Los taxones dominantes incluyeron tanto especies fotófilas como esciáfilas, lo que garantizó características peculiares a estas comunidades si se comparan con las típicas comunidades de macroalgas infralitorales y circalitorales de la misma área geográfica. Las comunidades mostraron una variabilidad a pequeña e intermedia escala mayor que a gran escala espacial. Si bien los afloramientos coralígenos infralitorales constituyen un sistema peculiar, aún son poco conocidos y deberían ser objeto no solo de estudios específicos sino también incluidos en programas de monitoreo ambiental