4,214 research outputs found
The development of television in the United States from 1923 to the present time which is May, 1950
Not available.Bernice F. GiulianoNot ListedNot ListedMaster of ScienceDepartment Not ListedCunningham Memorial Library, Terre Haute, Indiana State University.isua-thesis-1950-giulianoMastersTitle from document title page. Document formatted into pages: contains 92p. : ill. Includes appendix and bibliography
Simulation of the 2009, Mw = 4 Tehran earthquake using a hybrid method of modal summation and finite difference
The Greater Tehran Area is the most important city of Iran and hosts about 20% of the country?s population. Despite the presence of major faults and the occurrence of historical earthquakes, the seismicity is relatively low at present. Thus, it is important to estimate the ground motion for preventive, reliable seismic hazard assessment. An earthquake with magnitude Mw = 4, which occurred close to Tehran, 17 October 2009, is the first local earthquake that has been recorded by the local strong ground motion network in Tehran. To simulate the ground motion caused by the earthquake a hybrid technique is used. It combines two methods: the analytical modal summation and the numerical finite difference, taking advantage of the merits of both. The modal summation is applied to simulate wave propagation from the source to the sedimentary basin and finite difference to propagate the incoming wavefield in the laterally heterogeneous part of the structural model that contains the sedimentary basin. Synthetic signals are simulated along two East?West and Southeast?Northwest profiles. Frequency, response spectra, and time domain, waveforms and peak values, parameters are computed synthetically and compared with observed records. Results show agreement between observed and simulated signals. The simulation shows local site amplification as high as 6 in the southern part of Tehran
CONJUNCTION SCREENING AND COLLISION AVOIDANCE MANEUVER STRATEGIES FOR LOW THRUST SPACECRAFT
The number of objects in space has raised concern about the risk of operational satellites and debris colliding. The U.S. Space Surveillance Network currently tracks more than 27,000 objects; of these 7,500 are active payloads and 19,500 are debris. Satellite operators follow conjunction analysis procedures to ensure safe operations in this congested environment, and it is not rare for operators to have only the systems tool kit (STK) as a conjunction analysis tool. In this case, a common approach is to perform conjunction screening using the two-line elements (TLE) catalog. Even though it is the easiest and fastest way to perform this process in STK, NASA does not recommend this practice due to TLE’s low accuracy. Instead, NASA recommends using the special perturbation (SP) catalog developed for this purpose. Yet, the use of the SP catalog in STK is less straightforward than it is for TLE. This work proposes a program that allows the use of the full SP catalog for the screening process in STK. In the conjunction analysis process, an action is required when risk of collision exceeds an acceptable limit. For low-thrust satellites, it is challenging to select and perform a conjunction avoidance maneuver (CAM) that significantly reduces the collision risk. Tangential CAM and drag maneuvers are tested for the ICEYE satellites, a small electric-propulsion SAR satellite. Results show these two approaches are feasible for the ICEYE case, but some technical concerns are identified.Major, Brazilian Air ForceApproved for public release. Distribution is unlimited
Relaxation due to random collisions with a many-qudit environment
We analyze the dynamics of a system qudit of dimension mu sequentially
interacting with the nu-dimensional qudits of a chain playing the ore of an
environment. Each pairwise collision has been modeled as a random unitary
transformation. The relaxation to equilibrium of the purity of the system
qudit, averaged over random collisions, is analytically computed by means of a
Markov chain approach. In particular, we show that the steady state is the one
corresponding to the steady state for random collisions with a single
environment qudit of effective dimension nu_e=nu*mu. Finally, we numerically
investigate aspects of the entanglement dynamics for qubits (mu=nu=2) and show
that random unitary collisions can create multipartite entanglement between the
system qudit and the qudits of the chain.Comment: 7 pages, 6 figure
Interoperability between WiMAX and broadband mobile space networks
In several countries manufacturers, operators, and public authorities look at WiMAX system as a viable technology to fill the "digital divide," providing broadband services mainly in suburban and rural areas, but also in densely populated areas. Nevertheless, as a standalone system it will never offer global services, and to complement its capabilities, the utilization of broadband space-based access shared among users represents a scalable and cost-effective solution to offer wider area coverage, improved performance in terms of QoS, service continuity in case of terrestrial network failure, and long-range user mobility. Integration between WiMAX and a space-based infrastructure, composed of a combination of satellites and high altitude platforms, can be pursued in several ways. The simplest solution is based on connecting a WiMAX network by means of a terrestrial network terminating at a hub station connected to the space infrastructure. A more flexible solution should allow the WiMAX subscriber station or base station to directly access the space infrastructure. This article addresses the identification of suitable scenarios and a feasibility analysis presenting link budget results related to a subset of the identified solutions
Josephson current through a long quantum wire
The dc Josephson current through a long SNS junction receives contributions
from both Andreev bound states localized in the normal region as well as from
scattering states incoming from the superconducting leads. We show that in the
limit of a long junction, this current, at low temperatures, can be expressed
entirely in terms of properties of the Andreev bound states at the Fermi
energy: the normal and Andreev reflection amplitudes at the left-hand and at
the right-hand S-N interface. This has important implications for treating
interactions in such systems.Comment: 25 pages, 5 figure
In vivo analysis of staphylococcus aureus-infected mice reveals differential temporal and spatial expression patterns of fhuD2
Staphylococcus aureus is an opportunistic human pathogen and a major cause of invasive infections such as bacteremia, endocarditis, pneumonia and wound infections. FhuD2 is a staphylococcal lipoprotein involved in the uptake of iron-hydroxymate and is under the control of the iron uptake regulator Fur. The protein is part of an investigational multi-component vaccine formulation that has shown protective efficacy in several murine models of infection. Even though fhuD2 expression was shown to be upregulated in murine kidneys infected with S. aureus, it is unknown whether the bacterium undergoes increased iron deprivation during prolonged infection. Furthermore, different infection niches of S. aureus might provide different environments and iron availability resulting in different fhuD2 expression pattern within different host organs. To address these questions, we characterized the in vitro expression of the fhuD2 gene and confirmed Fur-dependent iron-regulation of its expression. We further investigated its expression in mice infected with a bioluminescent reporter strain of S. aureus expressing the luciferase operon under the control of the fhuD2 promoter. The emission of bioluminescence in different organs was followed over a seven-day time course, as well as quantitative real-time PCR analysis of the RNA transcribed from the endogenous fhuD2 gene. Using this approach, we could show that fhuD2 expression was induced during infection in all organs analyzed and that differences in expression were observed in the temporal expression profiles, and between infected organs. Our data suggest that S. aureus undergoes increased iron deprivation during progression of infection in diverse host organs and accordingly induces dedicated iron acquisition mechanisms. Since FhuD2 plays a central role in providing the pathogen with the required iron, further knowledge of the patterns of fhuD2 expression in vivo during infection is instrumental in better defining the role of this antigen in S. aureus pathogenesis and as a vaccine antigen
Family Ties and Political Participation
We establish an inverse relationship between family ties and political participation, such that the more individuals rely on the family as a provider of services, insurance, transfer of resources, the lower is one’s civic engagment and political participation. We also show that strong family ties appear to be a substitute for generalized trust, rather than a complement to it. These three constructs-civic engagement, political participation, and trust- are part of what is known as social capital; therefore, in this paper, we contribute to the investigation of the origin and evolution of social capital. We establish these results using within-country evidence and looking at the behavior of immigrants from various countries in 32 different destination places.
Preferences for Redistribution
This paper discusses what determines the preferences of individuals for redistribution. We review the theoretical literature and provide a framework to incorporate various effects previously studied separately in the literature. We then examine empirical evidence for the US, using the General Social Survey, and for a large set of countries, using the World Values Survey. The paper reviews previously found results and provides several new ones. We emphasize, in particular, the role of historical experiences, cultural factors and personal history as determinants of preferences for equality or tolerance for inequality.
Phase-space characterization of complexity in quantum many-body dynamics
We propose a phase-space Wigner harmonics entropy measure for many-body
quantum dynamical complexity. This measure, which reduces to the well known
measure of complexity in classical systems and which is valid for both pure and
mixed states in single-particle and many-body systems, takes into account the
combined role of chaos and entanglement in the realm of quantum mechanics. The
effectiveness of the measure is illustrated in the example of the Ising chain
in a homogeneous tilted magnetic field. We provide numerical evidence that the
multipartite entanglement generation leads to a linear increase of entropy
until saturation in both integrable and chaotic regimes, so that in both cases
the number of harmonics of the Wigner function grows exponentially with time.
The entropy growth rate can be used to detect quantum phase transitions. The
proposed entropy measure can also distinguish between integrable and chaotic
many-body dynamics by means of the size of long term fluctuations which become
smaller when quantum chaos sets in.Comment: 10 pages, 9 figure
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