Unimodal and cross-modal prediction is enhanced in musicians

Musical training involves exposure to complex auditory and visual stimuli, memorization of elaborate sequences, and extensive motor rehearsal. It has been hypothesized that such multifaceted training may be associated with differences in basic cognitive functions, such as prediction, potentially translating to a facilitation in expert musicians. Moreover, such differences might generalize to non-auditory stimuli. This study was designed to test both hypotheses. We implemented a cross-modal attentional cueing task with auditory and visual stimuli, where a target was preceded by compatible or incompatible cues in mainly compatible (80% compatible, predictable) or random blocks (50% compatible, unpredictable). This allowed for the testing of prediction skills in musicians and controls. Musicians showed increased sensitivity to the statistical structure of the block, expressed as advantage for compatible trials (disadvantage for incompatible trials), but only in the mainly compatible (predictable) blocks. Controls did not show this pattern. The effect held within modalities (auditory, visual), across modalities, and when controlling for short-term memory capacity. These results reveal a striking enhancement in cross-modal prediction in musicians in a very basic cognitive task

Release of Soluble Ligands for the Activating NKG2D Receptor: One More Immune Evasion Strategy Evolved by HIV-1?

ncreasing lines of evidence indicate that NKG2D, an activating receptor of natural killer (NK) and CD8(+) T cells, plays an important role in immune responses against HIV-1. Through its ability to recognize a diverse array of ligands (NKG2DLs) induced by cell 'stress' such as viral infection, NKG2D delivers activating and co-stimulatory signals resulting in cytotoxicity and release of cytokines. Therefore, HIV-1 and other viruses have evolved clever mechanisms to counteract NKG2D-dependent immune responses. While, on one hand, the HIV-1 Vpr protein up-regulates NKG2DLs expression by activating the DNA damage response (DDR) pathway, other viral proteins (Nef and Vif) have developed the capacity to reduce NKG2DLs expression levels. In addition, recent evidences suggest that HIV-1-infected CD4(+) T cells may release NKG2DLs, particularly MICA, in soluble form, a phenomenon that has the potential to down-modulate NKG2D on circulating lymphocytes and allow evasion of NKG2D-mediated immune responses. Indeed, despite controversial, lower NKG2D expression was found on both NK and CD8(+) T cells in HIV-1-infected patients. This review discusses recent advances in the understanding of how HIV-1 affects the NKG2D/NKG2DLs system, with a special focus on virus-induced release of soluble NKG2DLs and its functional implications for the immune surveillance of the infected host

Structural conditions for saddle-node bifurcations in chemical reaction networks

Motivated by investigating multistationarity in biochemical systems, we address saddle-node bifurcations for chemical reaction networks endowed with general kinetics. At positive equilibria, we identify structural network conditions that guarantee the bifurcation behavior, and we develop a method to identify the proper bifurcation parameters. As a relevant example, we explicitly provide such bifurcation parameters for Michaelis-Menten and Hill kinetics. Examples of applications include reversible feedback cycles, the central carbon metabolism of Escherichia coli, and autocatalytic networks.Comment: 32 page

Anti-apoptotic effects of Interleukin 7 in Human Immunodeficiency Virus Type 1 infection: Mechanism and implications for immune reconstitution strategies

Although HAART has introduced great improvements in the clinical outcome of HIV-1- infected individuals, the current protocols often fail in completely restoring the CD4+T-cell lymphopenia. Therefore, innovative approaches based on the use of immune adjuvants to HAART, including cytokines like IL-2, IL-15 and IL-7, are being explored. The present thesis aims at investigating the immunomodulatory effects of IL- 7 in HIV /SIV infection, focusing on its pro-survival properties. The first part of this work describes the results of a study in vitro to evaluate the effects of IL-7 on T cells from HIV -l-infected individuals, and shows that this cytokine strongly protects both CD4+ and CD8+T cells from spontaneous apoptosis. IL-7-mediated apoptosis reduction ex vivo inversely correlated with the CD4+T-cell count of the patient in vivo, suggesting that IL-7 treatment could be useful also for patients at with advanced disease. Moreover, the protective effect of IL-7 was not associated with the induction of cellular proliferation or viral replication. The second part of this work describes the results of a study in vivo of IL-7 administration during the acute phase of SIV infection in rhesus macaques, the pathogenic animal model for AIDS. IL-7 treatment prevented the depletion of circulating naive and memory CD4+T cells that typically occurs within the very first weeks of infection, primarily by reducing the levels of apoptosis. Moreover, IL-7 treatment also induced sustained increases in all subsets of circulating CD8+T cells. Of note, treatment with IL-7 did not have any effect on SIV plasma viral load nor on the content of SIV DNA provirus. Finally, IL-7-treated animals developed earlier and stronger CD8+ and CD4+T-cell responses as compared to untreated animals, although overall no protective effects on disease progression were observed. Taken together, these data further support the use of IL-7 as an immunomodulatory adjuvant to HAART in HIV-I-infected individuals, and suggest that this cytokine may be a useful tool to preserve or restore the CD4+T-cell pool during both the acute and chronic phases of the infection

Sign-sensitivity of metabolic networks: Which structures determine the sign of the responses

Perturbations are ubiquitous in metabolism. A central tool to understand and control their influence on metabolic networks is sensitivity analysis, which investigates how the network responds to external perturbations. We follow here a structural approach: the analysis is based on the network stoichiometry only and it does not require any quantitative knowledge of the reaction rates. We consider perturbations of reaction rates and metabolite concentrations, at equilibrium, and we investigate the responses in the network. For general metabolic systems, this paper focuses on the sign of the responses, that is, whether a response is positive, negative or whether its sign depends on the parameters of the system. In particular, we identify and describe the subnetworks that are the main players in the sign description. These subnetworks are associated to certain kernel vectors of the stoichiometric matrix and are thus independent from the chosen kinetics

Sensitivity of metabolic networks

In this thesis we present a comprehensive analysis of sensitivity of metabolic chemical reaction networks, with general kinetics. Sensitivity studies the network response to perturbations. We consider local perturbations of the network components - metabolite concentrations or reaction rates - at a dynamical equilibrium. We investigate the responses in the network, both of the metabolite concentrations and of the reaction fluxes. Firstly, we describe which components of the network respond, at all. Secondly, we analyze whether their responses are positive, negative, or whether the sign depends on the parameters of the system. Sign changes of the Jacobian determinant play an important overall role both in sensitivity analysis and in the bifurcation of equilibria. The first part of this thesis distinguishes reaction network Jacobians with constant sign from the bifurcation case, where that sign depends on specific values of reaction rates. Our approach is purely qualitative, rather than quantitative. In fact, our analysis is based, solely, on the stoichiometry of the reaction network. We do not require any quantitative information on the reaction rates. Instead, the description is done only in algebraic terms, and the only data required is the network structure. Biological applications include detection of multistationarity, enzyme knock-out experiments, and metabolic control.In dieser Arbeit präsentieren wir eine umfassende Sensitivitätsanalyse metabolischer Reaktionsnetzwerke mit allgemeiner Kinetik. Sensitivitätsanalyse meint hier das systematische Studium der Veränderung des Netzwerkkomponenten durch Störungen. Wir betrachten lokale Störungen eines dynamischen Gleichgewichts, das heißt, Störungen der Metabolitenkonzentrationen bzw. der Reaktionsgeschwindigkeiten. Wir untersuchen die resultierenden Veränderung der Metabolitenkonzentrationen als auch die der Reaktionsflüsse. Zunächst beschreiben wir, auf welche Komponenten des Netzwerks überhaupt eingewirkt wird. Zweitens analysieren wir, ob das Vorzeichen der Veränderung von den Parametern des Systems abhängt. Dabei spielen Vorzeichenänderungen der Jacobi-Determinante des Netzwerks eine wichtige Rolle, sowohl bei der Sensitivitätsanalyse als auch bei der Bifurkation von Gleichgewichten. Der erste Teil dieser Arbeit unterscheidet den Fall des konstanten Vorzeichens vom Bifurkationsfall, bei dem das Vorzeichen von den Werten der Reaktionsgeschwindigkeiten abhängt. Unser Ansatz ist eher qualitativ als quantitativ. Tatsächlich basiert unsere Analyse ausschließlich auf der Stöchiometrie des Reaktionsnetzwerks. Quantitative Angaben zu den Reaktionsgeschwindigkeiten sind nicht erforderlich. Stattdessen erfolgt die Beschreibung in rein algebraischen Begriffen, welche nur die Kenntnis der Netzwerkstruktur erfordern. Biologische Anwendungen umfassen den Nachweis von Multistationarität, Enzym-Knock-Out-Experimente und die Stoffwechselkontrolle

Outdoor and indoor mapping of a mining site by indoor mobile mapping and geo referenced Ground Control Scans

L’articolo descrive le metodologie di rilevamento messe in atto per effettuare il rilievo di una miniera sotterranea, nelle sue componenti indoor e outdoor. La parte esterna della miniera, localizzata in una vallata del Nord Italia, è soggetta a numerosi crolli che stanno interessando alcune abitazioni costruite nei pressi della miniera. Si è reso quindi necessario un rilievo tridimensionale globale per collegare la parte interna sotterranea della miniera con la parte esterna, e per effettuare uno studio geotecnico e geologico del comportamento globale del sito. La tecnologia basata su SLAM è stata scelta come la tecnologia più appropriata per rilevare la sezione sotterranea del sito minerario. Infatti la tecnologia iMMS garantisce la precisione richiesta di 3-4 cm, con la tempistica richiesta. Purtroppo l'accesso alla miniera dismessa era di difficile accesso, perché i due ingressi principali sono stati chiusi con terreno per evitare ingressi abusivi; le dimensioni degli ingressi hanno reso impossibile realizzare una classica rete topografica con stazione totale, misurare punti di controllo all'interno della miniera e collegare l'ambiente esterno a quello interno. L'unico modo trovato per collegare il modello tridimensionale della parte interna della miniera, misurata con iMMS, con quella esterna, è stato quello di applicare l'approccio innovativo dell'utilizzo di Ground Control Scans (GCS). Sono state effettuate diverse scansioni statiche in modo da assicurare un collegamento esterno/interno e le scansioni statiche acquisite nella parte a cielo aperto dei due ingressi minerari, sono state georeferenziate grazie a punti di controllo misurati con stazione totale collegata a vertici misurati con GNSS in RTK. In questo modo il modello 3D acquisito da iMMS è stato collegato alla parte esterna della miniera. L'utilizzo dei GCS è possibile all'interno del software di post-elaborazione SLAM, prima della generazione del modello finale della nuvola di punti. L'utilizzo dei GCS è utile anche per correggere gli effetti di deriva spesso presenti nell'approccio SLAM. Le derive altimetriche, nella parte della miniera sotterranea più lontana dai suoi ingressi, sono state ridotte grazie al trasporto dell'ambiente esterno nella quota interna della miniera, grazie ad un foro di ispezione realizzato a scopo ispettivo. L'esperienza mostra un'interessante integrazione tra diverse tecnologie di rilevamento

A new software for the solution of control networks in close range photogrammetry

This paper deals with a new software package supporting the treatment of topographic data needed by a stereoplotter working in close range photogrammetry. The main characteristics of each program and their way of working are here b~iefly presented