Linear Independence of a Finite Set of Dilations by a One-Parameter Matrix Lie Group

Let $G=\{e^{tA}:t\in\mathbb{R}\}$ be a closed one-parameter subgroup of the general linear group of matrices of order $n$ acting on $\mathbb{R}^{n}$ by matrix-vector multiplications. We assume that all eigenvalues of $A$ are rationally related. We study conditions for which the set ${f(e^{t_{1}A}.) ,.,f(e^{t_{m}A}.)}$ is linearly dependent in $L^{p}(\mathbb{R}^{n})$ with $1\leq p<\infty.

Distributed Smoothed Tree Kernel

In this paper we explore the possibility to merge the world of Compositional Distributional Semantic Models (CDSM) with Tree Kernels (TK). In particular, we will introduce a specific tree kernel (smoothed tree kernel, or STK) and then show that is possibile to approximate such kernel with the dot product of two vectors obtained compositionally from the sentences, creating in such a way a new CDSM

Household Migration and Child Educational Attainment: The Case of Uganda

In many Sub-Saharan African countries, a large number of people migrate internally or abroad because of demographic, economic and political factors. This pronounced mobility is likely to have consequences for child education, which is still a matter of concern in the region. We study this issue for Uganda, investigating whether the migration of household members affects child primary education and in what direction. Using the Uganda National Panel Survey for 2005, 2009, 2010 and 2011, we estimate conditional fixed effects logit models of school attendance and primary school completion. We find that migration of children has a significant positive impact on child school attendance rates while that of adults has a significantly negative effect, and that remittances have no influence. These findings suggest that migration of children is indeed beneficial, since it may contribute to matching the demand and supply of schooling. The absence of adults, instead, has controversial effects when children are left behind. In fact, lack of supervision and children working substituting adults in their tasks might reduce the rate of school attendance. However, the migration of neither children nor adults seem to increase the rate of primary school completion, evidence that points to the problem of the low quality of primary education in developing countries

International Launch Vehicle Selection for Interplanetary Travel

In developing a mission strategy for interplanetary travel, the first step is to consider launch capabilities which provide the basis for fundamental parameters of the mission. This investigation focuses on the numerous launch vehicles of various characteristics available and in development internationally with respect to upmass, launch site, payload shroud size, fuel type, cost, and launch frequency. This presentation will describe launch vehicles available and in development worldwide, then carefully detail a selection process for choosing appropriate vehicles for interplanetary missions focusing on international collaboration, risk management, and minimization of cost. The vehicles that fit the established criteria will be discussed in detail with emphasis on the specifications and limitations related to interplanetary travel. The final menu of options will include recommendations for overall mission design and strategy

In Situ Geophysical Exploration by Humans in Mars Analog Environments

We carried out three geophysical experiments in Mars analog environments in order to better understand the challenges future astronauts will face when conducting similar surveys on Mars or the Moon. The experiments included a passive seismometer deployment and a time-domain electromagnetic survey at the Flashline Mars Arctic Research Station (FMARS) on Devon Island, Canada and a seismic refraction survey in southeastern Utah at the Mars Desert Research Station (MDRS). FMARS is located on the rim of the 23 Ma Haughton Crater in a polar desert environment. MDRS is located in an area with sedimentary plateaus and canyons of Jurassic to Cretaceous age. Both facilities were built by The Mars Society to help develop key knowledge about human Mars exploration. Crews of six spend 2-4 weeks in the habitats and conduct eld research on simulated extravehicular activities (EVAs) wearing mock spacesuits. The work reported here was conducted in July 2009 at FMARS and February 2010 at MDRS

RHIC heavy ion operations performance

The Relativistic Heavy Ion Collider (RHIC) completed its fifth year of operation in 2005, colliding copper ion beams with ps=200 GeV/u and 62.4 GeV/u[1]. Previous heavy ion runs have collided gold ions at ps=130 GeV/u, 200 GeV/u, and 62.4 GeV/u[2], and deuterons and gold ions at ps=200 GeV/u[3]. This paper discusses operational performance statistics of this facility, including Cu- Cu delivered luminosity, availability, calendar time spent in physics stores, and time between physics stores. We summarize the major factors affecting operations efficiency, and characterize machine activities between physics stores