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Analysis of residual dependencies of independent components extracted from fMRI data
No full textIndependent component analysis (ICA) of functional magnetic resonance imaging (fMRI) data can be employed as an exploratory method. The lack in the ICA model of strong a priori assumptions about the signal or about the noise leads to difficult interpretations of the results. Moreover, the statistical independence of the components is only approximated. Residual dependencies among the components can reveal informative structure in the data. A major problem is related to model order selection, that is, the number of components to be extracted. Specifically, overestimation may lead to component splitting. In this work, a method based on hierarchical clustering of ICA applied to fMRI datasets is investigated. The clustering algorithm uses a metric based on the mutual information between the ICs. To estimate the similarity measure, a histogram-based technique and one based on kernel density estimation are tested on simulated datasets. Simulations results indicate that the method could be used to cluster components related to the same task and resulting from a splitting process occurring at different model orders. Different performances of the similarity measures were found and discussed. Preliminary results on real data are reported and show that the method can group task related and transiently task related components
Micro- and Macrostructured PLGA/Gelatin Scaffolds Promote Early Cardiogenic Commitment of Human Mesenchymal Stem Cells In Vitro
No full textThe biomaterial scaffold plays a key role in most tissue engineering strategies. Its surface properties, micropatterning, degradation, and mechanical features affect not only the generation of the tissue construct in vitro, but also its in vivo functionality. The area of myocardial tissue engineering still faces significant difficulties and challenges in the design of bioactive scaffolds, which allow composition variation to accommodate divergence in the evolving myocardial structure. Here we aimed at verifying if a microstructured bioartificial scaffold alone can provoke an effect on stem cell behavior. To this purpose, we fabricated microstructured bioartificial polymeric constructs made of PLGA/gelatin mimicking anisotropic structure and mechanical properties of the myocardium. We found that PLGA/gelatin scaffolds promoted adhesion, elongation, ordered disposition, and early myocardial commitment of human mesenchymal stem cells suggesting that these constructs are able to crosstalk with stem cells in a precise and controlled manner. At the same time, the biomaterial degradation kinetics renders the PLGA/gelatin constructs very attractive for myocardial regeneration approaches
Osservazioni sull’inconscio ottico
No full textThis essay is based on an analysis of the notion of “Optical Unconscious” by Walter Benjamin.
It seeks to present an interpretation of this notion in connection with the historical relationship between the birth of cinematic technology on the one hand and research conducted during the same period in the field of physiology investigating human and animal movement on the other hand.
To this end the essay analyzes the following three concepts: (a) alienation, (b) automatism and (c) invisibility.
(a) In "Minutiae, Close-up, Microanalysis", Carlo Ginzburg formulates an analogy to describe the “optical unconscious” and juxtaposes it with a page from Marcel Proust in which the alien gaze of the narrator parallels the imperturbable lens of a camera and he experiences the physiognomy of the objects in their anonymous being.
Through reference to this passage, I seek to prove that the meaning of the photographic image does not reside in its ability to reflect its object as something real and familiar, but rather in its ability to alienate this object and make it foreign to the observer.
(b) This paper will link this impersonality of the subject to the concept of automatism and analyze this link through William K.L. Dickson’s "Kinetoscopic Record of a Sneeze" (1894) as an example of the many images of the time that depicted an involuntary movement on the part of the represented subject, namely an action or series of actions beyond the subject’s control.
I assert that this idea of displaying the ordinariness of an involuntary action constitutes a specificity that both photographic and cinematographic technology are based on.
(c) The comprehensive meaning of the represented subject therefore depends on the device, otherwise it would have been doomed to invisibility. In order to clarify what kind of invisibility is at stake here, my study takes a step back to examine the historical origins of the photo-cinematographic tools used in experimental physiology and the role that representation came to have (the idea of the autonomy of the representation).
Finally, in order to clarify these hypotheses, this essay analyzes the case of the French physiologist Étienne-Jules Marey.
By studying physiological theories on motion at the end of XIX Century, the article seeks to bring the relationship between photography and cinema back to its historical origins and highlight moments of intersection
Are Supramodality and Cross-Modal Plasticity the Yin and Yang of Brain Development? From Blindness to Rehabilitation
No full textResearch in blind individuals has primarily focused for a long time on the brain plastic reorganization that occurs in early visual areas. Only more recently, scientists have developed innovative strategies to understand to what extent vision is truly a mandatory prerequisite for the brain’s fine morphological architecture to develop and function. As a whole, the studies conducted to date in sighted and congenitally blind individuals have provided ample evidence that several ‘visual’ cortical areas develop independently from visual experience and do process information content regardless of the sensory modality through which a particular stimulus is conveyed: a property named supramodality. At the same time, lack of vision leads to a structural and functional reorganization within 'visual' brain areas, a phenomenon known as cross-modal plasticity. Cross-modal recruitment of the occipital cortex in visually deprived individuals represents an adaptative compensatory mechanism that mediates processing of non-visual inputs. Supramodality and cross-modal plasticity appear to be the 'yin and yang' of brain development: supramodal is what takes place despite the lack of vision, whereas cross-modal is what happens because of lack of vision. Here we provide a critical overview of the research in this field and discuss the implications that these novel findings have for the development of educative/rehabilitation approaches and sensory substitution devices in sensory-impaired individuals
Tax Morale, Aversion to Ethnic Diversity, and Decentralization
No full textThis paper analyzes the relationship between individuals' aversion to ethnic diversity, the degree of fiscal and political decentralization, and tax morale. Our theory is based on the assumption that individuals are risk averse in contributing to the provision of public goods benefiting other ethnic groups, and threfore display a lower tax morale. We find scope for policy intervention-specifically, our model predicts that the effect of individuals' aversion to ethnic diversity on taxmorale is smaller or null in decentralized political and fiscal systems relative to centralized ones. The theory highlights the role of decentralization reforms to cut down inter-ethnic redistribution in con icting environments. We test our results by using individual data from the World Value Survey, and several decentralization measures from Fan et al. (2009). According to our most preferred estimation, a one-scale change in the attitude toward ethnic diversity reduces tax morale of 0.03 in centralized system. We rather find no impact in decentralized states
Sponsorship bias in the comparative efficacy of psychotherapy and pharmacotherapy for adult depression: meta-analysis
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Stochastic gradient methods for stochastic model predictive control
No full textWe introduce a new stochastic gradient algorithm, SAAGA, and investigate its employment for solving Stochastic MPC problems and multi-stage stochastic optimization programs in general. The method is particularly attractive for scenario-based formulations that involve a large number of scenarios, for which “batch” formulations may become inefficient due to high computational costs. Benefits of the method include cheap computations per iteration and fast convergence due to the sparsity of the proposed problem decomposition
La gestualità del dolore rituale tra parole e immagini
No full textThis paper deals with mourning gestures in Roman literary and iconographic productions. Both literature and iconography are thought to be the product of a shared cultural background but, at the same time, they show differences in the way each of them expresses this background: the literary form is dynamic, while the iconographic form seems to be static. Hence, ritual mourning scenes are analyzed either in literature (where some vivid details allow the reader to visualize what is being said through words) or in iconography (where an aoristic image stands for a durative narration). In particular, the analysis focuses on a selection of literary sources that contain vivid descriptions of ritual mourning scenes and date back to a period between the I century BC and the II century AD. They are compared to the conclamatio scenes that are portrayed on some groups of Urban sarcophagi, i.e. children sarcophagi and some mythological ones (depicting the death of Patroclus, Meleager, or Alcestis), all of which date back to the middle Imperial Age. Thus, this paper aims at decoding mourning gestures as well as drawing attention to the similarities and differences that can be detected between the literary horizon and the iconographic one in regard to this particular theme
Radiotherapy dose enhancement using {BNCT} in conventional {LINACs} high-energy treatment: Simulation and experiment
No full textAbstractAim To employ the thermal neutron background that affects the patient during a traditional high-energy radiotherapy treatment for {BNCT} (Boron Neutron Capture Therapy) in order to enhance radiotherapy effectiveness. Background Conventional high-energy (15–25 MV) linear accelerators (LINACs) for radiotherapy produce fast secondary neutrons in the gantry with a mean energy of about 1 MeV due to (γ, n) reaction. This neutron flux, isotropically distributed, is considered as an unavoidable undesired dose during the treatment. Considering the moderating effect of human body, a thermal neutron fluence is localized in the tumour area: this neutron background could be employed for {BNCT} by previously administering 10B-Phenyl-Alanine (10BPA) to the patient. Materials and methods Monte Carlo simulations (MCNP4B-GN code) were performed to estimate the total amount of neutrons outside and inside human body during a traditional X-ray radiotherapy treatment. Moreover, a simplified tissue equivalent anthropomorphic phantom was used together with bubble detectors for thermal and fast neutron to evaluate the moderation effect of human body. Results Simulation and experimental results confirm the thermal neutron background during radiotherapy of 1.55E07 cm−2 Gy−1. The {BNCT} equivalent dose delivered at 4 cm depth in phantom is 1.5 mGy-eq/Gy, that is about 3 Gy-eq (4 of X-rays dose) for a 70 Gy {IMRT} treatment. Conclusions The thermal neutron component during a traditional high-energy radiotherapy treatment could produce a localized {BNCT} effect, with a localized therapeutic dose enhancement, corresponding to 4 or more of photon dose, following tumour characteristics. This {BNCT} additional dose could thus improve radiotherapy, acting as a localized radio-sensitizer