The National Aeronautics and Space Administration (NASA)/Goddard Space Flight Center (GSFC) sounding-rocket program

An overall introduction to the NASA sounding rocket program as managed by the Goddard Space Flight Center is presented. The various sounding rockets, auxiliary systems (telemetry, guidance, etc.), launch sites, and services which NASA can provide are briefly described

Status of superpressure balloon technology in the United States

Superpressure mylar balloon technology in United States - applications, balloon size criteria, and possible improvement

Anti-platelet therapy in the prevention of hepatitis B virus-associated hepatocellular carcinoma

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Telling faults from cyber-attacks in a multi-modal logistic system with complex network analysis

We investigate the properties of systems of systems in a cybersecurity context by using complex network methodologies. We are interested in resilience and attribution. The first relates to the system's behavior in case of faults/attacks, namely to its capacity to recover full or partial functionality after a fault/attack. The second corresponds to the capability to tell faults from attacks, namely to trace the cause of an observed malfunction back to its originating cause(s). We present experiments to witness the effectiveness of our methodology considering a discrete event simulation of a multimodal logistic network featuring 40 nodes distributed across Italy and daily traffic roughly corresponding to the number of containers shipped through in Italian ports yearly averaged daily

THE SEROTONIN TRANSPORTER KNOCKOUT RAT: MODELLING DEPRESSION FROM ETIOLOGY TO PHARMACOLOGICAL TREATMENT

Major depression is a complex disorder characterized by the interaction of genetic, biological, social and environmental factors, which play in concert to determine the development of the disease. The serotonin transporter gene is of particular relevance in the context of mood disorders because it is the target of several antidepressant drugs and, due to the presence of a functional polymorphism within its promoter region, it has been associated with different neuropsychiatric disorders (Caspi et al., 2003; Uher and McGuffin, 2008). Since the molecular mechanisms contributing to depression pathophysiology are still poorly understood, several genetic or environmental animal models of depression have been developed in order to reproduce the depressive phenotype and to characterize the molecular alterations of the disease. Among these, rodents (mice or rats) with a total deletion of the serotonin transporter represent a good model of anxiety and depression phenotypes and they have been extensively characterized at behavioral level (Holmes et al., 2003; Lira et al., 2003; Olivier et al., 2008), although a detailed analyses of the molecular phenotype associated with genetic alterations of SERT is still lacking. In particular, limited information exists on potential changes in neuronal plasticity, which is strongly associated with depression. Indeed it has been proposed that psychopathology may be associated with reduced expression and function of key mediators of neuronal plasticity, such as the neurotrophin brain-derived neurotrophic factor (BDNF), (McClung and Nestler, 2008; Pittenger and Duman, 2008). Given all these premises, in this study, we investigated the expression of BDNF in different brain regions of adult SERT mutant rats (+/ 12 and 12/ 12). Moreover, since the neurotrophin has a complex genomic structure (Aid et al., 2007), we have investigated the influence of SERT deletion on its different transcripts and evaluated the involvement of several transcription factors in BDNF expression changes found in SERT mutant animals. Moreover, considering that the depressive phenotype of SERT mutant animals appears to originate from the lack of the transporter during early life (Ansorge et al., 2004; Ansorge et al., 2008), we also assessed when the neuroplastic alteration of SERT-/- animals are established, by investigating the expression of BDNF in SERT knockout rats during postnatal development. One system lying downstream from Npas4 and BDNF that may be relevant for the phenotype of SERT mutants is GABA. Indeed, Npas4 regulates the development of GABAergic synapses (Lin et al., 2008), while BDNF alteration can affect GABAergic cellular architecture and transmission (Sakata et al., 2009). Therefore we also established if SERT mutant rats are characterized by alterations in the expression of key GABAergic markers that may eventually contribute to the depressive phenotype of these animals. A further aspect of the experimental work is aimed at addressing the issue of gene * environment interaction in mood disorders. Indeed, stressful experiences can exacerbate or precipitate depressive disorder in genetically-prone individuals (Caspi et al., 2003). In particular adverse events early in life may impact on brain structures that are not completely matured resulting critical for the development of psychopathology later in life. In order to establish if the molecular phenotype associated with deletion of SERT gene could be modulated by early life events, we exposed SERT mutant rats (+/ 12 and 12/ 12) to maternal deprivation, a strong form of stress, and we assessed the expression of the neurotrophin BDNF as marker of neuronal plasticity. Last we investigated if pharmacological intervention in SERT mutant rats may restore neuroplastic defects associated with the vulnerable genotype. Therefore we chronically treated SERT knockout rats with the antidepressant duloxetine (a SNRI, dual blocker of the reuptake of the serotonin and norepinephrine) and we assessed its ability to normalize the expression of different neuroplastic genes that are significantly altered in mutant rats. We demosntarted that animals carrying a deletion of the SERT gene show a reduction of BDNF expression, which may contribute to their pathologic phenotype. This impairment originates early in development and is associated with reduction of transcription factors and GABAergic markers, suggesting that these defects may contribute to behavioral phenotype associated with SERT-/-, and in particular those that are relevant for anxiety and depression. Moreover these animals maintain the ability to show neuroplastic changes in response to antidepressant drugs, possibly via the blockade of the noradrenaline transporter. The molecular characterization of the SERT mutant rat may prove useful to elucidate the pathophysiology of the depressive disorder and may eventually lead to the development of new effective treatments

XAI.it 2021 - Preface to the Second Italian Workshop on Explainable Artificial Intelligence

Artificial Intelligence systems are increasingly playing an increasingly important role in our daily lives. As their importance in our everyday lives grows, it is fundamental that the internal mechanisms that guide these algorithms are as clear as possible. It is not by chance that the recent General Data Protection Regulation (GDPR) emphasized the users' right to explanation when people face artificial intelligencebased technologies. Unfortunately, the current research tends to go in the opposite direction, since most of the approaches try to maximize the effectiveness of the models (e.g., recommendation accuracy) at the expense of the explainability and the transparency. The main research questions which arise from this scenario is straightforward: how can we deal with such a dichotomy between the need for effective adaptive systems and the right to transparency and interpretability? Several research lines are triggered by this question: building transparent intelligent systems, analyzing the impact of opaque algorithms on final users, studying the role of explanation strategies, investigating how to provide users with more control in the behavior of intelligent systems. XAI.it, the Italian workshop on Explainable AI, tries to address these research lines and aims to provide a forum for the Italian community to discuss problems, challenges and innovative approaches in the various sub-fields of XAI

Poly(Alkylene 2,5-thiophenedicarboxylate) polyesters: A new class of bio-based high-performance polymers for sustainable packaging

In the present study, 100% bio-based polyesters of 2,5-thiophenedicarboxylic acid were synthesized via two-stage melt polycondensation using glycols containing 3 to 6 methylene groups. The so-prepared samples were characterised from the molecular point of view and processed into free-standing thin films. Afterward, both the purified powders and the films were subjected to structural and thermal characterisation. In the case of thin films, mechanical response and barrier properties to O2 and CO2 were also evaluated. From the results obtained, it emerged that the length of glycolic sub-units is an effective tool to modulate the chain mobility and, in turn, the kind and amount of ordered phases developed in the samples. In addition to the usual amorphous and 3D crystalline phases, in all the samples investigated it was possible to evidence a further phase characterised by a lower degree of order (mesophase) than the crystalline one, whose amount is strictly related to the glycol sub-unit length. The relative fraction of all these phases is responsible for the different mechanical and barrier performances. Last, but not least, a comparison between thiophene-based homopolymers and their furan-based homologues was carried out

Joint Graph-based User Scheduling and Beamforming in LEO-MIMO Satellite Communication Systems

In this paper, a Low earth orbit (LEO) High-Throughput Satellite (HTS) Multi-User multiple-input multiple-output (MIMO) system is considered. With the objective of minimizing inter-beam interference among users, we propose a joint graph-based user scheduling and feed space beamforming framework for the downlink. First, we construct a graph where the vertices are the users and edges are based on a dissimilarity measure of their channels. Secondly, we design a low complexity greedy user clustering strategy, in which we iteratively search for the maximum clique in the graph. Finally, a Minimum Mean Square Error (MMSE) beamforming matrix is applied on a cluster basis with different power normalization schemes. A heuristic optimization of the graph density, i.e., optimal cluster size, is performed in order to maximize the system capacity. The proposed scheduling algorithm is compared with a position-based scheduler, in which a beam lattice is generated on ground and one user per beam is randomly selected to form a cluster. Results are presented in terms of achievable per-user capacity and show the superiority in performance of the proposed scheduler w.r.t. to the position-based approach

Improved Graph-Based User Scheduling For Sum-Rate Maximization in LEO-NTN Systems

In this paper, we study the problem of user scheduling for Low Earth Orbit (LEO) Multi-User (MU) Multiple-Input-Multiple-Output (MIMO) Non-Terrestrial Network (NTN) systems with the objective of maximizing the sum-rate capacity while minimizing the total number of clusters. We propose an iterative graph-based maximum clique scheduling approach with constant graph density. Users are grouped together based on the channel coefficient of correlation (CoC) as dissimilarity metric and served by the satellite via Space Division Multiple Access (SDMA) by means of Minimum Mean Square Error (MMSE) digital beamforming on a cluster basis. Clusters are then served in different time slots via Time Division Multiple Access (TDMA). The results, presented in terms of per-cluster sum-rate capacity and per-user throughput, show that the presented approach can significantly improve the system performance