387 research outputs found

    Influence of Motivation on the Efficacy of Natural Family Planning

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    Purpose: Mutual motivation is recognized as essential for effective behavioral methods of family planning. Few studies have studied this factor in family planning efficacy. The purpose of this study was to determine the influence of mutual motivation on unintended pregnancy rates of couples who used natural family planning (NFP) methods to avoid pregnancy. Study Design and Methods: Using an online taught NFP method, 358women and ( their male partners) indicated “how much” and “how hard” they wished to avoid pregnancy on a scale of 0-10 before each menstrual cycle charted over 12 month of use. This motivation scale is used in the National Survey of Family Growth as a measure of motivation. All pregnancies were verified with an online pregnancy evaluation and urine based pregnancy test. A combined motivation score was used in analysis. Results: There were 28 pregnancies among the low motivation participants (N=60) and 16 among the high motivation participants (N=298). At 12 months of use, there were 75 pregnancies per 100 users for the low motivation group and only 8 for the high motivation group. There was an 80% greater likelihood of a pregnancy with the low motivation group (χ2 = 25.5, p \u3c .001) OR = 1.80; 95% CI = 1.61-1.90). Clinical Implications: High motivation to avoid pregnancy by both the female user of a behavioral method of family planning and her male partner is required for high efficacy. Assessing motivation of both the woman and her male partner before prescribing NFP methods is recommended

    Systematic hybrid analog/digital signal coding

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    Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. 201-206).This thesis develops low-latency, low-complexity signal processing solutions for systematic source coding, or source coding with side information at the decoder. We consider an analog source signal transmitted through a hybrid channel that is the composition of two channels: a noisy analog channel through which the source is sent unprocessed and a secondary rate-constrained digital channel; the source is processed prior to transmission through the digital channel. The challenge is to design a digital encoder and decoder that provide a minimum-distortion reconstruction of the source at the decoder, which has observations of analog and digital channel outputs. The methods described in this thesis have importance to a wide array of applications. For example, in the case of in-band on-channel (IBOC) digital audio broadcast (DAB), an existing noisy analog communications infrastructure may be augmented by a low-bandwidth digital side channel for improved fidelity, while compatibility with existing analog receivers is preserved. Another application is a source coding scheme which devotes a fraction of available bandwidth to the analog source and the rest of the bandwidth to a digital representation. This scheme is applicable in a wireless communications environment (or any environment with unknown SNR), where analog transmission has the advantage of a gentle roll-off of fidelity with SNR. A very general paradigm for low-latency, low-complexity source coding is composed of three basic cascaded elements: 1) a space rotation, or transformation, 2) quantization, and 3) lossless bitstream coding. The paradigm has been applied with great success to conventional source coding, and it applies equally well to systematic source coding. Focusing on the case involving a Gaussian source, Gaussian channel and mean-squared distortion, we determine optimal or near-optimal components for each of the three elements, each of which has analogous components in conventional source coding. The space rotation can take many forms such as linear block transforms, lapped transforms, or subband decomposition, all for which we derive conditions of optimality. For a very general case we develop algorithms for the design of locally optimal quantizers. For the Gaussian case, we describe a low-complexity scalar quantizer, the nested lattice scalar quantizer, that has performance very near that of the optimal systematic scalar quantizer. Analogous to entropy coding for conventional source coding, Slepian-Wolf coding is shown to be an effective lossless bitstream coding stage for systematic source coding.by Richard J. Barron.Ph.D

    Channel equalization for self-synchronizing chaotic systems

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.Includes bibliographical references (p. 75-77).by Richard J. Barron.M.S

    In Memoriam: Daniel J. Meltzer

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    Sedan år 2006 har den syntetiskt framställda drogen spice existerat i Sverige, men först år 2008 blev drogen populär och tidningar började rikta uppmärksamhet mot den. Genom att drogen kan byta skepnad i uppbyggnaden kan den förbli laglig, därför kan egentligen namnet “spice” inte betraktas som ett enhetligt begrepp. Vårt syfte med denna studie blev att granska hur drogen spice beskrivs i tidningar och forskning. Även hur drogen betraktas gällande psykosociala och medicinska avseenden. Detta i förhållande till socialkonstruktivistiskt perspektiv. Den metod som vi valde att använda oss av i studien var kvantitativ innehållsanalys. Genom analys av 80 stycken svenska tidningsartiklar hämtade ur databasen mediearkivet, samt vetenskapliga artiklar och litteratur har vi besvarat våra frågeställningar. De resultat vi fick från analyser visade på att tidningar kan vara av betydande roll för ungdomars attityder. Tidningar kan utföra bland annat skrämselpropaganda för att upplysa och förhindra brukandet av spice, dessvärre visar resultatet en motsatt effekt. Forskning visar att bruk av spice kan påverka relationer och arbete negativt. Dessutom är några bieffekter av spice bröstsmärtor, vanföreställningar, självmordstankar och hjärtstopp

    Cancer chemotherapy treatment patterns and febrile neutropenia in the US Veterans Health Administration

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    Onur Başer (MEF Author)Background: The Veterans Health Administration (VHA) is the largest integrated health care system in the United States and a major cancer care provider. Objective: To use VHA database to conduct a population-based study of patterns of myelosuppressive chemotherapy use and to assess the incidence and management of febrile neutropenia (FN) among VHA patients with lung, colorectal, or prostate cancer or non-Hodgkin lymphoma (NHL). Methods: Data were extracted for the initial myelosuppressive chemotherapy course for 27,899 patients who began treatment in the period 2006 to 2011. FN-related costs were defined as claims containing FN diagnosis. Results: Most patients were men (98.0%); most were 65 years or older (55.8%). Patients received a mean 3.4 to 3.9 chemotherapy cycles/course (median cycle duration 34-43 days). The incidence of FN among patients with lung, colorectal, or prostate cancer or NHL was 10.2%, 4.6%, 5.4%, and 17.3%, respectively. Primary or secondary prophylactic antibiotics/colony-stimulating factors were received by 21% and 12% of patients, respectively. Antibiotics were more commonly given as primary or secondary prophylaxis for patients with lung, colorectal, and prostate cancer; colony-stimulating factors were more common for patients with NHL. Among patients with FN, those with lung cancer had the highest inpatient mortality (10%); patients with NHL had the highest costs ($24,571) and the longest hospital length of stay (15.4 days). Conclusions: VHA cancer care was generally consistent with National Comprehensive Cancer Network recommendations; however, compared with the general population, chemotherapy cycles were longer, combination chemotherapy was used less, and treatment to prevent FN was used less, differences that may be attributed to the unique VHA patient population. The impact of these practices warrants further investigation.WOS:000342363300010Scopus - Affiliation ID: 60105072PMID: 25236998Science Citation Index Expanded - Social Sciences Citation IndexQ1ArticleUluslararası işbirliği ile yapılan - EVETEylül2014YÖK - 2014-1

    Report of the panel on the land surface: Process of change, section 5

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    The panel defined three main areas of study that are central to the Solid Earth Science (SES) program: climate interactions with the Earth's surface, tectonism as it affects the Earth's surface and climate, and human activities that modify the Earth's surface. Four foci of research are envisioned: process studies with an emphasis on modern processes in transitional areas; integrated studies with an emphasis on long term continental climate change; climate-tectonic interactions; and studies of human activities that modify the Earth's surface, with an emphasis on soil degradation. The panel concluded that there is a clear requirement for global coverage by high resolution stereoscopic images and a pressing need for global topographic data in support of studies of the land surface

    Enhancement of Multiwalled Carbon Nanotubes’ Electrical Conductivity Using Metal Nanoscale Copper Contacts and Its Implications for Carbon Nanotube-Enhanced Copper Conductivity

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    Herein, we present an experimental/computational approach for probing the interaction between metal contacts and carbon nanotubes (CNTs) with regard to creating the most efficient, low resistance junction. Tungsten probes have been coated with copper or chromium and the efficiency of nanocontact transport into multiwalled carbon nanotubes (MWCNTs) has been investigated experimentally, using scanning tunneling spectroscopy and nanoscale two-point probe I-V measurements, and in silico, employing DFT calculations. Experimental I-V measurements suggest the relative conductivity of the metal-CNT interaction to be Cu > W > Cr. It has been found that copper when in contact with MWCNTs results in a high density of states at the Fermi level, which contributes states to the conduction band. It was observed that the density of states also increased when chromium and tungsten probes were in contact with CNTs; however, in these cases the density of states increase would only occur under high voltage/high temperature situations. This is demonstrated by an increase in the experimental electrical resistance when compared to the copper probe. These results suggest that in future copper tips should be used when carrying out all intrinsic conduction measurements on CNTs, and they also provide a rationale for the ultraconductivity of Cu-CNT and Cu-graphene composites

    Low Complexity Regularization of Linear Inverse Problems

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    Inverse problems and regularization theory is a central theme in contemporary signal processing, where the goal is to reconstruct an unknown signal from partial indirect, and possibly noisy, measurements of it. A now standard method for recovering the unknown signal is to solve a convex optimization problem that enforces some prior knowledge about its structure. This has proved efficient in many problems routinely encountered in imaging sciences, statistics and machine learning. This chapter delivers a review of recent advances in the field where the regularization prior promotes solutions conforming to some notion of simplicity/low-complexity. These priors encompass as popular examples sparsity and group sparsity (to capture the compressibility of natural signals and images), total variation and analysis sparsity (to promote piecewise regularity), and low-rank (as natural extension of sparsity to matrix-valued data). Our aim is to provide a unified treatment of all these regularizations under a single umbrella, namely the theory of partial smoothness. This framework is very general and accommodates all low-complexity regularizers just mentioned, as well as many others. Partial smoothness turns out to be the canonical way to encode low-dimensional models that can be linear spaces or more general smooth manifolds. This review is intended to serve as a one stop shop toward the understanding of the theoretical properties of the so-regularized solutions. It covers a large spectrum including: (i) recovery guarantees and stability to noise, both in terms of â„“2\ell^2-stability and model (manifold) identification; (ii) sensitivity analysis to perturbations of the parameters involved (in particular the observations), with applications to unbiased risk estimation ; (iii) convergence properties of the forward-backward proximal splitting scheme, that is particularly well suited to solve the corresponding large-scale regularized optimization problem
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