Low Mass Neutron Stars and the Equation of State of Dense Matter

Neutron-star radii provide useful information on the equation of state of neutron rich matter. Particularly interesting is the density dependence of the equation of state (EOS). For example, the softening of the EOS at high density, where the pressure rises slower than anticipated, could signal a transition to an exotic phase. However, extracting the density dependence of the EOS requires measuring the radii of neutron stars for a broad range of masses. A ``normal'' 1.4 solar mass neutron star has a central density of a few times nuclear-matter saturation density. In contrast, low mass (of the order of 0.5 solar masses) neutron stars have central densities near nuclear-matter saturation density so its radius provides information on the EOS at low density. Unfortunately, low-mass stars are rare because they may be hard to form. Instead, a precision measurement of nuclear radii on atomic nuclei may contain similar information. Indeed, we find a strong correlation between the neutron radius of 208Pb and the radius of a 0.5 solar-mass neutron star. Thus, the radius of such a neutron star can be inferred from a measurement of the the neutron radius of 208Pb. Comparing this value to the measured radius of a 1.4 solar-mass neutron star should provide the strongest constraint to date on the density dependence of the equation of state.Comment: 9 pages and 5 eps. figures (included

Climate Change and Co-operative Housing in Nova Scotia: Evaluating Adaptation Readiness, Policy, and Transformative Potential

Canada faces overlapping crises in both accelerating climate change impacts and the diminishing availability of affordable housing. As governments at all levels respond to these challenges, a critical gap has emerged in our understanding of how different forms of housing tenure are being integrated into Canadian climate adaptation governance, and how decisions around equity and social vulnerability are factored into planning and policy processes. This thesis examines how adaptation plans and policies in Nova Scotia are integrating the needs of the non-profit co-operative housing sector into climate adaptation and assesses the adaptation readiness of housing co-operatives in the province. Two methods are employed: a systematic content analysis of municipal and provincial climate policy documents, and interviews with key informants across the co-operative housing sector and government agencies. Analysis is structured around a modified adaptation readiness framework which includes measures for equity, justice, and inclusion, and considers the potential for transformational adaptation which prompts systemic change and addresses the root causes of social vulnerability. Findings indicate that non-market forms of tenure, including co-operative housing, are largely neglected in adaptation policy and planning for NS. Several barriers which contribute to an overall low level of adaptation readiness for co-ops are highlighted, notably a lack of usable science and funding to facilitate adaptation. There are characteristics which position housing co-ops to be agents of transformational change at the intersection of housing systems and adaptation, as evidenced by emerging models of decommodified development, a propensity for participatory collective action, and professional and grassroots co-operative leadership which is willing to engage with the challenge of climate change. This potential will only be realized if key barriers are overcome through explicit attention to non-profit housing and social justice by adaptation planners and state policymakers

Nonuniform Neutron-Rich Matter and Coherent Neutrino Scattering

Nonuniform neutron-rich matter present in both core-collapse supernovae and neutron-star crusts is described in terms of a semiclassical model that reproduces nuclear-matter properties and includes long-range Coulomb interactions. The neutron-neutron correlation function and the corresponding static structure factor are calculated from molecular dynamics simulations involving 40,000 to 100,000 nucleons. The static structure factor describes coherent neutrino scattering which is expected to dominate the neutrino opacity. At low momentum transfers the static structure factor is found to be small because of ion screening. In contrast, at intermediate momentum transfers the static structure factor displays a large peak due to coherent scattering from all the neutrons in a cluster. This peak moves to higher momentum transfers and decreases in amplitude as the density increases. A large static structure factor at zero momentum transfer, indicative of large density fluctuations during a first-order phase transition, may increase the neutrino opacity. However, no evidence of such an increase has been found. Therefore, it is unlikely that the system undergoes a simple first-order phase transition. It is found that corrections to the commonly used single heavy nucleus approximation first appear at a density of the order of $10^{13}$ g/cm$^3$ and increase rapidly with increasing density. Thus, neutrino opacities are overestimated in the single heavy nucleus approximation relative to the complete molecular dynamics simulations.Comment: 17 pages, 23 included ps figure

Pygmies, Giants, and Skins

Understanding the equation of state (EOS) of neutron-rich matter is a central goal of nuclear physics that cuts across a variety of disciplines. Indeed, the limits of nuclear existence, the collision of energetic heavy ions, the structure of neutron stars, and the dynamics of core-collapse supernova all depend critically on the nuclear-matter EOS. In this contribution I focus on the EOS of cold baryonic matter with special emphasis on its impact on the structure, dynamics, and composition of neutron stars. In particular, I discuss how laboratory experiments on neutron skins as well as on Pygmy and Giant resonances can help us elucidate the structure of these fascinating objects.Comment: Invited Talk given at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS

Modelling stochastic bivariate mortality

Stochastic mortality, i.e. modelling death arrival via a jump process with stochastic intensity, is gaining increasing reputation as a way to represent mortality risk. This paper represents a first attempt to model the mortality risk of couples of individuals, according to the stochastic intensity approach. On the theoretical side, we extend to couples the Cox processes set up, i.e. the idea that mortality is driven by a jump process whose intensity is itself a stochastic process, proper of a particular generation within each gender. Dependence between the survival times of the members of a couple is captured by an Archimedean copula. On the calibration side, we fit the joint survival function by calibrating separately the (analytical) copula and the (analytical) margins. First, we select the best fit copula according to the methodology of Wang and Wells (2000) for censored data. Then, we provide a sample-based calibration for the intensity, using a time-homogeneous, non mean-reverting, affine process: this gives the analytical marginal survival functions. Coupling the best fit copula with the calibrated margins we obtain, on a sample generation, a joint survival function which incorporates the stochastic nature of mortality improvements and is far from representing independency.On the contrary, since the best fit copula turns out to be a Nelsen one, dependency is increasing with age and long-term dependence exists

Remote multiparametric monitoring and management of heart failure patients through cardiac implantable electronic devices

In this review we focus on heart failure (HF) which, as known, is associated with a substantial risk of hospitalizations and adverse cardiovascular outcomes, including death. In recent years, systems to monitor cardiac function and patient parameters have been developed with the aim to detect subclinical pathophysiological changes that precede worsening HF. Several patient-specific parameters can be remotely monitored through cardiac implantable electronic devices (CIED) and can be combined in multiparametric scores predicting patients’ risk of worsening HF with good sensitivity and moderate specificity. Early patient management at the time of pre-clinical alerts remotely transmitted by CIEDs to physicians might prevent hospitalizations. However, it is not clear yet which is the best diagnostic pathway for HF patients after a CIED alert, which kind of medications should be changed or escalated, and in which case in-hospital visits or in-hospital admissions are required. Finally, the specific role of healthcare professionals involved in HF patient management under remote monitoring is still matter of definition. We analyzed recent data on multiparametric monitoring of patients with HF through CIEDs. We provided practical insights on how to timely manage CIED alarms with the aim to prevent worsening HF. We also discussed the role of biomarkers and thoracic echo in this context, and potential organizational models including multidisciplinary teams for remote care of HF patients with CIEDs

Large-scale magnetic field in the Monoceros OB 1 east molecular cloud

Context. The role of large-scale magnetic fields in the evolution of star-forming regions remains elusive. Its investigation requires the observational characterization of well-constrained molecular clouds. The Monoceros OB 1 molecular cloud is a large complex containing several structures that have been shown to be engaged in an active interaction and to have a rich star formation history. However, the magnetic fields in this region have only been studied on small scales. Aims. We study the large-scale magnetic field structure and its interplay with the gas dynamics in the Monoceros OB 1 east molecular cloud. Methods. We combined observations of dust polarized emission from the Planck telescope and CO molecular line emission observations from the Taeduk Radio Astronomy Observatory 14-metre telescope. We calculated the strength of the plane-of-sky magnetic field using a modified Chandrasekhar-Fermi method and estimated the mass-over-flux ratios in different regions of the cloud. We used the comparison of the velocity and intensity gradients of the molecular line observations with the polarimetric observations to trace dynamically active regions. Results. The molecular complex shows an ordered large-scale plane-of-sky magnetic field structure. In the northern part, it is mostly orientated along the filamentary structures, while the southern part shows at least two regions with distinct magnetic field orientations. Our analysis reveals a shock region in the northern part right between two filamentary clouds that, in previous studies, were suggested to be involved in a collision. The magnetic properties of the north-main and north-eastern filaments suggest that these filaments once formed a single one, and that the magnetic field evolved together with the material and did not undergo major changes during the evolution of the cloud. In the southern part, we find that either the magnetic field guides the accretion of interstellar matter towards the cloud or it is dragged by the matter falling towards the main cloud. Conclusions. The large-scale magnetic field in the Monoceros OB 1 east molecular cloud is tightly connected to the global structure of the complex. In the northern part, it seems to serve a dynamically important role by possibly providing support against gravity in the direction perpendicular to the field and to the filament. In the southern part, it is probably the most influential factor governing the morphological structure by guiding possible gas inflow. A study of the whole Monoceros OB 1 molecular complex at large scales is necessary to form a global picture of the formation and evolution of the Monoceros OB 1 east cloud and the role of the magnetic field in this process.Peer reviewe

Analysis of ETC or Classical Manometric closed vessel tests with coupling of thermodynamic equilibrium calculations: combustion rate, Energy losses

We performed closed vessel tests to study the combustion of several gun pro-pellants ignited classically or by ETC. We analysed the results to estimate the combustion rates and energy losses to the bomb wall. The classical STANAG 4115 method for the determination of the combustion rate of solid gun propel- lants classically ignited was adapted for ETC conditions. The experimental combustion rates obtained were compared with existing more fundamental ex- pressions of this rate by coupling thermodynamic equilibrium calculations with the experimental results. This coupling allows also the estimation of energy losses to the bomb wall. As this research is still underway, we present the more significant results on a double base propellant (NC/NGL) and their present interpretation and limits

Fluoromycobacteriophages for rapid, specific, and sensitive antibiotic susceptibility testing of Mycobacterium tuberculosis

Rapid antibiotic susceptibility testing of Mycobacterium tuberculosis is of paramount importance as multiple- and extensively- drug resistant strains of M. tuberculosis emerge and spread. We describe here a virus-based assay in which fluoromycobacteriophages are used to deliver a GFP or ZsYellow fluorescent marker gene to M. tuberculosis, which can then be monitored by fluorescent detection approaches including fluorescent microscopy and flow cytometry. Pre-clinical evaluations show that addition of either Rifampicin or Streptomycin at the time of phage addition obliterates fluorescence in susceptible cells but not in isogenic resistant bacteria enabling drug sensitivity determination in less than 24 hours. Detection requires no substrate addition, fewer than 100 cells can be identified, and resistant bacteria can be detected within mixed populations. Fluorescence withstands fixation by paraformaldehyde providing enhanced biosafety for testing MDR-TB and XDR-TB infections. © 2009 Piuri et al