The Chromospheric Solar Millimeter-wave Cavity; a Common Property in the Semi-empirical Models

The semi-empirical models of the solar chromosphere are useful in the study of the solar radio emission at millimeter - infrared wavelengths. However, current models do not reproduce the observations of the quiet sun. In this work we present a theoretical study of the radiative transfer equation for four semi- empirical models at these wavelengths. We found that the Chromospheric Solar Milimeter-wave Cavity (CSMC), a region where the atmosphere becomes locally optically thin at millimeter wavelengths, is present in the semi-empirical models under study. We conclude that the CSMC is a general property of the solar chromosphere where the semi-empirical models shows temperature minimum.Comment: Accepted in Geofisica Internaciona

Non-parametric resampling of random walks for spectral network clustering

Parametric resampling schemes have been recently introduced in complex network analysis with the aim of assessing the statistical significance of graph clustering and the robustness of community partitions. We propose here a method to replicate structural features of complex networks based on the non-parametric resampling of the transition matrix associated with an unbiased random walk on the graph. We test this bootstrapping technique on synthetic and real-world modular networks and we show that the ensemble of replicates obtained through resampling can be used to improve the performance of standard spectral algorithms for community detection.Comment: 5 pages, 2 figure

Graph analysis of functional brain networks: practical issues in translational neuroscience

The brain can be regarded as a network: a connected system where nodes, or units, represent different specialized regions and links, or connections, represent communication pathways. From a functional perspective communication is coded by temporal dependence between the activities of different brain areas. In the last decade, the abstract representation of the brain as a graph has allowed to visualize functional brain networks and describe their non-trivial topological properties in a compact and objective way. Nowadays, the use of graph analysis in translational neuroscience has become essential to quantify brain dysfunctions in terms of aberrant reconfiguration of functional brain networks. Despite its evident impact, graph analysis of functional brain networks is not a simple toolbox that can be blindly applied to brain signals. On the one hand, it requires a know-how of all the methodological steps of the processing pipeline that manipulates the input brain signals and extract the functional network properties. On the other hand, a knowledge of the neural phenomenon under study is required to perform physiological-relevant analysis. The aim of this review is to provide practical indications to make sense of brain network analysis and contrast counterproductive attitudes

“Love Is…”: An Inaesthetic Inquiry on Love and Attention in Aureus Solito’s The Blossoming of Maximo Oliveros

Drawing from Alain Badiou’s concept of inaesthetics, which proposes that art conditions philosophical thought, this essay offers an inaesthetic reading of The Blossoming of Maximo Oliveros (2005) and suggests that it is a film that offers enabling possibilities in the thinking of love by providing the spectator with a different experience of cinematic attention in the visual field. The author suggests that the film raises the philosophical question “What is love?” and attempts to answer the very question it poses through punctual encounters, which are moments of cinematic interruption—described by Roland Barthes as “what I add . . . and what nonetheless is already there” (A Lover’s Discourse 55)—that may offer opportunities for philosophical speculation. This essay further argues that those punctual moments initiate a new form of attention that is not sustained by “visual pleasure,” as theorized by Laura Mulvey, but by the “movement of thought” (Badiou, Cinema 17). The film uses that mode of attention as a way to think about love while also suggesting that love itself is a form of attention

Building a Trademark Safe Harbor for Contributory Counterfeiting Liaibility After Tiffany v. eBay

(Excerpt) Since current anti-counterfeiting tools are not easily applied to the Internet, thereby diminishing their effectiveness, this Note argues that compensating for this deficiency requires legal provisions that encourage online service providers to implement both proactive and reactive anti-counterfeiting measures. After Tiffany, e-commerce businesses in the United States are only required to react appropriately to counterfeiting on their websites. Though it is well-settled that trademark owners must police their own brand, the Tiffany decision makes it extremely difficult and costly for owners to combat counterfeiting on their own. Furthermore, the Second Circuit’s application of a reactive law written specifically for secondary copyright infringement on the Internet does not effectively address the entire temporal range of harm posed by trademark infringement. Part I discusses the goals and policies underlying American trademark law and explains where counterfeiting fits in this framework. This Part also traces the development of the judicially-created doctrine of contributory trademark law and how it has been applied in counterfeiting cases. Part II compares the American approach to contributory trademark infringement to that of European courts. Part III analyzes and assesses how each approach addresses the harms of contributory trademark infringement on the Internet. Part IV proposes a legislative solution similar to the safe-harbor provisions of the DMCA, but tailored to the specific goals, policies, and harms faced by trademark owners. While the Second Circuit properly decided that a notice-and-takedown procedure is one effective way to combat trademark infringement on the Internet, it is a reactive mechanism that does not effectively address harms to trademarks owners and consumers that accrue even before someone buys a counterfeit item. For this reason, a safe-harbor provision for trademark law should incentivize online marketplaces like eBay to take preventive action against trademark infringement

Infrared excesses in stars with and without planets using revised WISE{\it WISE} photometry

We present an analysis on the potential prevalence of mid infrared excesses in stars with and without planetary companions. Based on an extended database of stars detected with the ${\it WISE}$ satellite, we studied two stellar samples: one with 236 planet hosts and another with 986 objects for which planets have been searched but not found. We determined the presence of an excess over the photosphere by comparing the observed flux ratio at 22 $\mu$m and 12 $\mu$m ($f_{22}/f_{12}$) with the corresponding synthetic value, derived from results of classical model photospheres. We found a detection rate of 0.85$\%$ at 22 $\mu$m (2 excesses) in the sample of stars with planets and 0.1$\%$ (1 detection) for the stars without planets. The difference of the detection rate between the two samples is not statistically significant, a result that is independent of the different approaches found in the literature to define an excess in the wavelength range covered by ${\it WISE}$ observations. As an additional result, we found that the ${\it WISE}$ fluxes required a normalisation procedure to make them compatible with synthetic data, probably pointing out a revision of the ${\it WISE}$ data calibration.Comment: 10 pages, 6 figures, 3 tables. Accepted for publication in MNRA

Hierarchy of neural organization in the embryonic spinal cord: Granger-causality graph analysis of in vivo calcium imaging data

The recent development of genetically encoded calcium indicators enables monitoring in vivo the activity of neuronal populations. Most analysis of these calcium transients relies on linear regression analysis based on the sensory stimulus applied or the behavior observed. To estimate the basic properties of the functional neural circuitry, we propose a network-based approach based on calcium imaging recorded at single cell resolution. Differently from previous analysis based on cross-correlation, we used Granger-causality estimates to infer activity propagation between the activities of different neurons. The resulting functional networks were then modeled as directed graphs and characterized in terms of connectivity and node centralities. We applied our approach to calcium transients recorded at low frequency (4 Hz) in ventral neurons of the zebrafish spinal cord at the embryonic stage when spontaneous coiling of the tail occurs. Our analysis on population calcium imaging data revealed a strong ipsilateral connectivity and a characteristic hierarchical organization of the network hubs that supported established propagation of activity from rostral to caudal spinal cord. Our method could be used for detecting functional defects in neuronal circuitry during development and pathological conditions