The Swift Gamma-Ray Burst redshift distribution: selection biases and optical brightness evolution at high-z?

We employ realistic constraints on astrophysical and instrumental selection effects to model the Gamma-Ray Burst (GRB) redshift distribution using {\it Swift} triggered redshift samples acquired from optical afterglows (OA) and the TOUGH survey. Models for the Malmquist bias, redshift desert, and the fraction of afterglows missing because of host galaxy dust extinction, are used to show how the "true" GRB redshift distribution is distorted to its presently observed biased distribution. We also investigate another selection effect arising from a correlation between $E_{{\rm iso}}$ and $L_{{\rm opt}}$. The analysis, which accounts for the missing fraction of redshifts in the two data subsets, shows that a combination of selection effects (both instrumental and astrophysical) can describe the observed GRB redshift distribution. Furthermore, the observed distribution is compatible with a GRB rate evolution that tracks the global SFR, although the rate at high-$z$ cannot be constrained with confidence. Taking selection effects into account, it is not necessary to invoke high-energy GRB luminosity evolution with redshift to explain the observed GRB rate at high-$z$.Comment: Version 2. Includes new data, figures and refined analysi

Long-Term Synaptic Changes Induced in the Cerebellar Cortex by Fear Conditioning

AbstractTo better understand learning mechanisms, one needs to study synaptic plasticity induced by behavioral training. Recently, it has been demonstrated that the cerebellum is involved in the consolidation of fear memory. Nevertheless, how the cerebellum contributes to emotional behavior is far from known. In cerebellar slices at 10 min and 24 hr following fear conditioning, we found a long-lasting potentiation of the synapse between parallel fibers and Purkinje cells in vermal lobules V-VI, but not in the climbing fiber synapses. The mechanism is postsynaptic, due to an increased AMPA response. In addition, in hotfoot mice with a primary deficiency of the parallel fiber to Purkinje cell synapse, cued (but not contextual) fear conditioning is affected. We propose that this synapse plays an important role in the learned fear and that its long-term potentiation may represent a contribution to the neural substrate of fear memory

Development of a perovskite-based interface for biophysical studies

LAUREA MAGISTRALEL’impiego della luce come sorgente di stimolazione per cellule e tessuti ha recentemente generato un ventaglio di promettenti applicazioni in biologia, medicina e robotica. Nell’ultimo decennio, infatti, il controllo delle vie neurali o delle funzioni vitali per mezzo di stimoli luminosi, definito spesso semplicemente come fotostimolazione, è emerso come potente alternativa alla stimolazione elettrica, per i suoi notevoli vantaggi in termini di invasività, risoluzione temporale e spaziale. Tuttavia, siccome le cellule in genere non possiedono particolare sensibilità alla luce, indurre artificialmente questo tipo di sensibilità è senza dubbio il primo obiettivo di tutte le tecniche di fotostimolazione. In questo studio, substrati di film sottili di perovskite sono stati proposti come fototransduttori esogeni in grado di tradurre l’eccitazione luminosa in un appropriato segnale per le cellule. L’archetipo perovskitico CH3NH3PbI3 è stato scelto come materiale fondamentale per la preparazione di substrati con il comportamento simile a quello di una cella solare. Inoltre, la deposizione conforme di uno strato di Parylene C è stata proposta come metodo di passivazione delle perovskiti, rivelandosi promettente. Quindi, il substrato incapsulato dal polimero è stato sottoposto ad esperimenti di elettrochimica per verificare il suo comportamento in un ambiente che replicasse le condizioni fisiologiche. Un modello di circuito equivalente è stato sviluppato per interpretare meglio i risultati sperimentali. Le simulazioni LTspice hanno confermato in buona parte la validità del modello aiutando a comprendere meglio alcuni aspetti dei fenomeni elettrochimici. I prossimi passi di questa attività di ricerca saranno naturalmente quelli di verificare l’effettiva biocompatibilità dei fototransduttori proposti e studiare l’eventuale risposta delle cellule. Quest’ultima analisi sarà auspicabilmente una pietra miliare importante per una comprensione più profonda dei meccanismi di accoppiamento che regolano l’eccitazione cellulare.The use of light for the stimulation of living cells and tissues has recently opened a wide range of possible applications in biology, medicine, and robotics. In the last decade, control of neuronal paths or vital functions by means of light-based stimuli, simply referred as photostimulation, has effectively emerged as a valid alternative to the electrical counterpart. Yet, since living cells do not generally possess any specific sensitivity to light, artificially inducing light sensitivity to cells is the primary goal of photostimulation techniques. Here, perovskite-based substrates are proposed as an external phototransducer that translates the light excitation in a proper signal for the cells. A perovskite archetype crystal (CH3NH3PbI3) has been selected as the raw material for the preparation of solar cell-like substrate, given its outstanding optical properties. Then, chemical vapor deposition of Parylene C has been proven as a promising biocompatible alternative to standard inorganic passivation techniques. The compactness and the uniformity of the coating has been shown to be the key for a successful encapsulation, rather than thickness. The so obtained substrate were tested with electrochemical measurements to assess the response of the system in a condition similar to a physiological environment. Also, an equivalent circuit model has been developed to properly interpret the results from electrochemistry. Hence, transient simulations performed with LTspice have been conducted to replicate the experimental conditions and validate the model proposed. The model has been demonstrated to be in good agreement with the experimental results and was useful for the interpretation of the system behaviour. The natural evolution of this study is the approach to cell culture to validate the compatibility of the explored substrates with life. Then, the eventual response of cells to the optoelectronic coupling provided by such substrates has to be further studied and interpreted. This future activity will hopefully shed light on the coupling mechanisms of cell excitation related to the plasma membrane

Different substrates of non-sustained ventricular tachycardia in post-infarction patients with and without left ventricular dilatation

Background: We investigated the relationship between nonsustained ventricular tachycardia (NSVT) and left ventricular (LV) dilatation, function, remodeling, and scar tissue extent in patients with previous myocardial infarction (MI). Methods and Results: Eighty-two patients (ages 64610 years) with first previous MI were referred for 24-hour electrocardiogram recording and cine and delayed enhancement (DE) cardiac magnetic resonance (CMR). LVvolumes, ejection fraction, systolic wall thickening, sphericity index, and core and peri-infarctual areas of scar tissue by CMR were evaluated. LV dilatation was observed in 39 patients. Episodes of NSVT were recorded in 32 patients: 23 with LV dilatation and 9 without. In the entire population, NSVTwas related to ejection fraction, LV volumes, LV mass, and sphericity index; end-systolic volume (P5.001) resulted in the only independent predictor at multivariate analysis. In patients without LV dilatation, the occurrence of NSVTwas only positively related with percentage of contracting segments with DE (P5.008). Conversely, in patients with LV dilatation, increase in LV mass (P5.020) and end-systolic volume (P5.038) were independent predictors of NSVT. Conclusions: Necrotic and viable myocardium coexistence within the same wall segments predicted occurrence of NSVT in patients without LV dilatation, whereas LV mass and end-systolic volume were predictors of NSVT in those with LV dilatation. (J Cardiac Fail 2010;16:61e68

Early Home Therapies against Covid-19. An Italian Case of Politicisation of Science?

Since February 2020, strategies aimed at containing and managing the Covid-19 syndemic have been developed by the governments of European countries. Among these measures, the possibility of an early treatment of the disease has been considered of fundamental importance, both for curing the disease and governing the syndemic. Despite their potential, early therapies received a somehow unexpected treatment in Italy and the debate around them gave rise to a very evident conflict between proponents and opponents of those treatments, to the point that some of the former organised a properly political movement in order to promote the integration of early home therapies in the official health protocols. Not surprisingly, the issue of early therapies has been considered an exemplary case of politicisation of science. However, the assimilation of the early therapy controversy to the frame of politicisation of science cannot fully explain why these protocols were discarded by political and health authorities. Rather, the consideration of health protocols as socio-technical objects shifts the attention on the vast range of cultural, political and economic factors that contributed to the general resistance towards those treatments. Therefore, we aim to analyse the media coverage of the phenomenon, and investigate the protocols of home treatment of Covid-19, paying attention to the interaction of the factors that contributed to the exclusion of home therapies into national guidelines

Performance of a U-OWC – PTO coupled system using different control laws

The problem of maximizing the performances of a U-OWC wave energy converter in a variet of environmental conditions is investigated. Specifically, the paper compares two control strategies coupling the U-OWC – PTO system. Two approaches are discussed. The first relies on the tracking of the Maximum Power Points of the system, and empirical relations between the optimal PTO performances and the energy content of the incident sea state are estimated. Secondly, an analytical formulation linking the operational conditions of the turbine to the instantaneous air pressure inside the pneumatic chamber is identified. Results show that a sea state-based controller works better than a wave-to wave fast-acting control

Early Home Therapies against Covid-19. An Italian Case of Politicisation of Science?

Since February 2020, strategies aimed at containing and managing the Covid-19 syndemic have been developed by the governments of European countries. Among these measures, the possibility of an early treatment of the disease has been considered of fundamental importance, both for curing the disease and governing the syndemic. Despite their potential, early therapies received a somehow unexpected treatment in Italy and the debate around them gave rise to a very evident conflict between proponents and opponents of those treatments, to the point that some of the former organised a properly political movement in order to promote the integration of early home therapies in the official health protocols. Not surprisingly, the issue of early therapies has been considered an exemplary case of politicisation of science. However, the assimilation of the early therapy controversy to the frame of politicisation of science cannot fully explain why these protocols were discarded by political and health authorities. Rather, the consideration of health protocols as socio-technical objects shifts the attention on the vast range of cultural, political and economic factors that contributed to the general resistance towards those treatments. Therefore, we aim to analyse the media coverage of the phenomenon, and investigate the protocols of home treatment of Covid-19, paying attention to the interaction of the factors that contributed to the exclusion of home therapies into national guidelines

Survey of moisture distribution between tile drainage laterals and its relationship to compaction and rooting depth in flat clay soils

Three tile drained farms on flat, poorly drained Brookston clay soil in northern Essex County were studied with respect to soil moisture distribution between drainage laterals and its relationship to compaction, root growth, crop development, and yields. The survey type study was carried out under uncontrolled conditions in order not to interfere with the cropping program and schedule of the three farmer cooperators. No significant increase in soil density (and hence compaction) was observed on one farm which had tomatoes in its rotation the year before the study. Mean dry densities were lower on this farm than on the other farms studied.Information from this study suggests that a soil moisture content of 20% represents optimum conditions for soil compaction on Brookston clay, and that agricultural equipment and implement traffic should be avoided at or near this moisture content, if possible. It was noted that soil moisture contents at harvest time are generally below 20%. Therefore, harvesting equipment and loaders for intensive cropping (tomatoes) should not pose a soil compaction problem on Brookston clay soil, unless there is a wetter than normal harvesting season. Marked soil cracking was observed on all farms during the summer months. Principally because of these cracks, summer rains percolate very quickly below tile drain invert level. This tendency for relatively quick drainage during summer months is felt to be limiting adequate wetting of the root zone, and may also be contributing to undesirable removal of soil nutrients. Due to the small number of farms and the overview scope of this study, firm conclusions could not be drawn for all parameters studied. Some observed trends require confirmation through further specific dedicated research, under controlled conditions, as outlined in the recommendations given in this report.Agriculture Canad