Multimessenger Parameter Estimation of GW170817

We combine gravitational wave (GW) and electromagnetic (EM) data to perform a Bayesian parameter estimation of the binary neutron star (NS) merger GW170817. The EM likelihood is constructed from a fit to a large number of numerical relativity simulations which we combine with a lower bound on the mass of the remnant's accretion disk inferred from the modeling of the EM light curve. In comparison with previous works, our analysis yields a more precise determination of the tidal deformability of the binary, for which the EM data provide a lower bound, and of the mass ratio of the binary, with the EM data favoring a smaller mass asymmetry. The 90\% credible interval for the areal radius of a $1.4\ M_\odot$ NS is found to be $12.2^{+1.0}_{-0.8} \pm 0.2\ {\rm km}$ (statistical and systematic uncertainties).Comment: 7 pages, 3 figures, accepted to the EPJA Topical Issue: The first Neutron Star Merger Observation - Implications for Nuclear Physic

Community programs and women's participation : the Chinese experience

Using household data specifically collected for the purpose of evaluation, the authors empirically evaluate the impact on household income of a rural program in China that focuses on increasing women's economic and social participation in the local community. They find that the program substantially increases women's participation and household income, and also generates positive social benefits. The authors'results also suggest that the income gains accrue only to participants, and partly at the expense of nonparticipants. They find that the magnitude of the program's impact depends sensitively on the program's ability to increase participation rates within villages. In the presence of the program, individual participation helps to prevent negative externalities and to buy into the positive gains accruing to participants. The authors'results support the view that effectively implemented gender-focused interventions can have substantial social benefits when supported by the necessary legal and institutional framework.Decentralization,Primary Education,Public Health Promotion,Health Economics&Finance,Poverty Monitoring&Analysis,Health Economics&Finance,Poverty Monitoring&Analysis,Primary Education,Housing&Human Habitats,Governance Indicators

A Hierarchical Rate Splitting Strategy for FDD Massive MIMO under Imperfect CSIT

In a multiuser MIMO broadcast channel, the rate performance is affected by the multiuser interference when the Channel State Information at the Transmitter (CSIT) is imperfect. To tackle the interference problem, a Rate-Splitting (RS) approach has been proposed recently, which splits one user's message into a common and a private part, and superimposes the common message on top of the private messages. The common message is drawn from a public codebook and should be decoded by all users. In this paper, we propose a novel and general framework, denoted as Hierarchical Rate Splitting (HRS), that is particularly suited to FDD massive MIMO systems. HRS simultaneously transmits private messages intended to each user and two kinds of common messages that can be decoded by all users and by a subset of users, respectively. We analyse the asymptotic sum rate of HRS under imperfect CSIT. A closed-form power allocation is derived which provides insights into the effects of system parameters. Finally, simulation results validate the significant sum rate gain of HRS over various baselines.Comment: Accepted paper at IEEE CAMAD 201

Top-Rank Enhanced Listwise Optimization for Statistical Machine Translation

Pairwise ranking methods are the basis of many widely used discriminative training approaches for structure prediction problems in natural language processing(NLP). Decomposing the problem of ranking hypotheses into pairwise comparisons enables simple and efficient solutions. However, neglecting the global ordering of the hypothesis list may hinder learning. We propose a listwise learning framework for structure prediction problems such as machine translation. Our framework directly models the entire translation list's ordering to learn parameters which may better fit the given listwise samples. Furthermore, we propose top-rank enhanced loss functions, which are more sensitive to ranking errors at higher positions. Experiments on a large-scale Chinese-English translation task show that both our listwise learning framework and top-rank enhanced listwise losses lead to significant improvements in translation quality.Comment: Accepted to CONLL 201

Thermal Conductance of an Individual Single-Wall Carbon Nanotube above Room Temperature

The thermal properties of a suspended metallic single-wall carbon nanotube (SWNT) are extracted from its high-bias (I-V) electrical characteristics over the 300-800 K temperature range, achieved by Joule self-heating. The thermal conductance is approximately 2.4 nW/K and the thermal conductivity is nearly 3500 W/m/K at room temperature for a SWNT of length 2.6 um and diameter 1.7 nm. A subtle decrease in thermal conductivity steeper than 1/T is observed at the upper end of the temperature range, which is attributed to second order three-phonon scattering between two acoustic modes and one optical mode. We discuss sources of uncertainty and propose a simple analytical model for the SWNT thermal conductivity including length and temperature dependence.Comment: Nano Letters, vol. 6, no. 1, 200

Electro-Thermal Transport in Metallic Single-Wall Carbon Nanotubes for Interconnect Applications

This work represents the first electro-thermal study of metallic single-wall carbon nanotubes (SWNTs) for interconnect applications. Experimental data and careful modeling reveal that self-heating is of significance in short (1 < L < 10 um) nanotubes under high-bias. The low-bias resistance of micron scale SWNTs is also found to be affected by optical phonon absorption (a scattering mechanism previously neglected) above 250 K. We also explore length-dependent electrical breakdown of SWNTs in ambient air. Significant self-heating in SWNT interconnects can be avoided if power densities per unit length are limited to less than 5 uW/um.Comment: IEEE Intl. Electron Devices Meeting (IEDM), Dec. 2005, Washington D