A Markov Chain Monte Carlo approach to the study of massive black hole binary systems with LISA

The Laser Interferometer Space Antenna (LISA) will produce a data stream containing a vast number of overlapping sources: from strong signals generated by the coalescence of massive black hole binary systems to much weaker radiation form sub-stellar mass compact binaries and extreme-mass ratio inspirals. It has been argued that the observation of weak signals could be hampered by the presence of loud ones and that they first need to be removed to allow such observations. Here we consider a different approach in which sources are studied simultaneously within the framework of Bayesian inference. We investigate the simplified case in which the LISA data stream contains radiation from a massive black hole binary system superimposed over a (weaker) quasi-monochromatic waveform generated by a white dwarf binary. We derive the posterior probability density function of the model parameters using an automatic Reversible Jump Markov Chain Monte Carlo algorithm (RJMCMC). We show that the information about the sources and noise are retrieved at the expected level of accuracy without the need of removing the stronger signal. Our analysis suggests that this approach is worth pursuing further and should be considered for the actual analysis of the LISA data.Comment: submitted to cqg as GWDAW-10 conference proceedings, 10 pages, 4 figures, some changes to plots and numerical detail

The information content of gravitational wave harmonics in compact binary inspiral

The nonlinear aspect of gravitational wave generation that produces power at harmonics of the orbital frequency, above the fundamental quadrupole frequency, is examined to see what information about the source is contained in these higher harmonics. We use an order (4/2) post-Newtonian expansion of the gravitational wave waveform of a binary system to model the signal seen in a spaceborne gravitational wave detector such as the proposed LISA detector. Covariance studies are then performed to determine the ultimate accuracy to be expected when the parameters of the source are fit to the received signal. We find three areas where the higher harmonics contribute crucial information that breaks degeneracies in the model and allows otherwise badly-correlated parameters to be separated and determined. First, we find that the position of a coalescing massive black hole binary in an ecliptic plane detector, such as OMEGA, is well-determined with the help of these harmonics. Second, we find that the individual masses of the stars in a chirping neutron star binary can be separated because of the mass dependence of the harmonic contributions to the wave. Finally, we note that supermassive black hole binaries, whose frequencies are too low to be seen in the detector sensitivity window for long, may still have their masses, distances, and positions determined since the information content of the higher harmonics compensates for the information lost when the orbit-induced modulation of the signal does not last long enough to be apparent in the data.Comment: 13 pages, 5 figure

LISA Response Function and Parameter Estimation

We investigate the response function of LISA and consider the adequacy of its commonly used approximation in the high-frequency range of the observational band. We concentrate on monochromatic binary systems, such as white dwarf binaries. We find that above a few mHz the approxmation starts becoming increasingly inaccurate. The transfer function introduces additional amplitude and phase modulations in the measured signal that influence parameter estmation and, if not properly accounted for, lead to losses of signal-to-noise ratio.Comment: 4 pages, 2 figures, amaldi 5 conference proceeding

Media use during adolescence: the recommendations of the Italian Pediatric Society.

BACKGROUND: The use of media device, such as smartphone and tablet, is currently increasing, especially among the youngest. Adolescents spend more and more time with their smartphones consulting social media, mainly Facebook, Instagram and Twitter because. Adolescents often feel the necessity to use a media device as a means to construct a social identity and express themselves. For some children, smartphone ownership starts even sooner as young as 7 yrs, according to internet safety experts. MATERIAL AND METHODS: We analyzed the evidence on media use and its consequences in adolescence. RESULTS: In literature, smartphones and tablets use may negatively influences the psychophysical development of the adolescent, such as learning, sleep and sigh. Moreover, obesity, distraction, addiction, cyberbullism and Hikikomori phenomena are described in adolescents who use media device too frequently. The Italian Pediatric Society provide action-oriented recommendations for families and clinicians to avoid negative outcomes. CONCLUSIONS: Both parents and clinicians should be aware of the widespread phenomenon of media device use among adolescents and try to avoid psychophysical consequences on the youngest

The Effect of the LISA Response Function on Observations of Monochromatic Sources

The Laser Interferometer Space Antenna (LISA) is expected to provide the largest observational sample of binary systems of faint sub-solar mass compact objects, in particular white-dwarfs, whose radiation is monochromatic over most of the LISA observational window. Current astrophysical estimates suggest that the instrument will be able to resolve about 10000 such systems, with a large fraction of them at frequencies above 3 mHz, where the wavelength of gravitational waves becomes comparable to or shorter than the LISA arm-length. This affects the structure of the so-called LISA transfer function which cannot be treated as constant in this frequency range: it introduces characteristic phase and amplitude modulations that depend on the source location in the sky and the emission frequency. Here we investigate the effect of the LISA transfer function on detection and parameter estimation for monochromatic sources. For signal detection we show that filters constructed by approximating the transfer function as a constant (long wavelength approximation) introduce a negligible loss of signal-to-noise ratio -- the fitting factor always exceeds 0.97 -- for f below 10mHz, therefore in a frequency range where one would actually expect the approximation to fail. For parameter estimation, we conclude that in the range 3mHz to 30mHz the errors associated with parameter measurements differ from about 5% up to a factor of 10 (depending on the actual source parameters and emission frequency) with respect to those computed using the long wavelength approximation.Comment: replacement version with typos correcte

Analysis of Care Coordination for Children with Special Health Care Needs: A Parent\u27s Perspective

Introduction. Care coordination involves organizing patient care activities and sharing information among all of the participants concerned with a patient\u27s care to achieve improved outcomes, a recent national focus. Compared to the national average, a higher percentage of Vermont children are cared for in an office that meets medical home criteria. However, there is limited research on medical home and care coordination for children with special health care needs (CSHCN) in the state of Vermont. Objectives. The goal of this study was to assess family perceptions, knowledge, and attitudes about how well care coordination is working for Vermont families with CSHCN. Methods. A paper and an electronic anonymous survey was developed for Vermont families with CSHCN. The surveys were then distributed by Vermont Family Network and the UVMMC Department of Pediatrics. Focus group interviews were also conducted at Vermont Family Network to provide family insight to explain the quantitative data. Results. 30 participants responded to the survey; only 20 completed it. The overall composite satisfaction score is 54%. This score takes into account 4 questions regarding care coordination satisfaction. Each question was formatted into a numerical value ranging from zero to five, with an overall score of 20 equating to 100% satisfaction. Discussion. Findings indicate that families with CSHCN are not satisfied with the level of care coordination currently provided. Respondents reported many barriers regarding care coordination, including lack of communication among health care providers, insurance coverage, and lack of support during transitional periods in care. Recommended improvements were identified.https://scholarworks.uvm.edu/comphp_gallery/1251/thumbnail.jp

The conserved immunoglobulin domain controls the subcellular localization of the homophilic adhesion receptor protein-tyrosine phosphatase mu

The receptor protein-tyrosine phosphatase mu (PTPmu) is a homophilic adhesion protein thought to regulate cell-cell adhesion in the vascular endothelium through dephosphorylation of cell junction proteins. In subconfluent cell cultures, PTPmu resides in an intracellular membrane pool; however, as culture density increases and cell contacts form, the phosphatase localizes to sites of cell-cell contact, and its expression level increases. These characteristics of PTPmu, which are consistent with a role in cell-cell adhesion, suggest that control of subcellular localization is an important mechanism to regulate the function of this phosphatase. To gain a better understanding of how PTPmu is regulated, we examined the importance of the conserved immunoglobulin domain, containing the homophilic binding site, in control of the localization of the enzyme. Deletion of the immunoglobulin domain impaired localization of PTPmu to the cell-cell contacts in endothelial and epithelial cells. In addition, deletion of the immunoglobulin domain affected the distribution of PTPmu in subconfluent endothelial cells when homophilic binding to another PTPmu molecule on an apposing cell was not possible, resulting in an accumulation of the mutant phosphatase at the cell surface with a concentration at the cell periphery in the region occupied by focal adhesions. This aberrant localization correlated with reduced survival and alterations in normal focal adhesion and cytoskeleton morphology. This study therefore illustrates the critical role of the immunoglobulin domain in regulation of the localization of PTPmu and the importance of such control for the maintenance of normal cell physiology

The case for new rural centralities in agricultural enclaves: three scenarios for Muggiano

Agricultural enclaves represent for cities both a challenge, they have to deal with connectivity and development issues, and an opportunity, they can be considered as resources for achieving major policy objectives such as better environmental protection or increased local food production. Among European metropolises, Milan’s case is quite original since it presents unique institutional arrangements and chiefly its agricultural park (Parco Agricolo Sud Milano – PASM). The territory of Muggiano is part of the PASM, at the fringe of the municipal territory, cut out from both the rest of the city and the rest of the park, it is undergoing a slow decline both in its agricultural and urban functions. Yet, field exploration revealed a more complex territory than expected, carrying a strong latent potential and presenting different challenges than expected. In a prospective effort, we elaborated 3 scenarios for the development of Muggiano: from a fully agricultural production one to another extreme one, focusing on residential uses. Our exploration led us to concluding that the “rural centrality” scenario, investing fully on agriculture but not only for its productive function, and spatially balancing the development along a “backbone”, was the best option Muggiano could go for

Optical properties of V2O3 in its whole phase diagram

Vanadium sesquioxide V2O3 is considered a textbook example of Mott-Hubbard physics. In this paper we present an extended optical study of its whole temperature/doping phase diagram as obtained by doping the pure material with M=Cr or Ti atoms (V1-xMx)2O3. We reveal that its thermodynamically stable metallic and insulating phases, although macroscopically equivalent, show very different low-energy electrodynamics. The Cr and Ti doping drastically change both the antiferromagnetic gap and the paramagnetic metallic properties. A slight chromium content induces a mesoscopic electronic phase separation, while the pure compound is characterized by short-lived quasiparticles at high temperature. This study thus provides a new comprehensive scenario of the Mott-Hubbard physics in the prototype compound V2O3