We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < or =Q2 < or =1.0 GeV2. These asymmetries, arising from interference of ...the electromagnetic and neutral weak interactions, are sensitive to strange-quark contributions to the currents of the proton. The measurements were made at Jefferson Laboratory using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate nonzero, Q2 dependent, strange-quark contributions and provide new information beyond that obtained in previous experiments.
We have studied the quasielastic He-3(e,e(')p)H-2 reaction in perpendicular coplanar kinematics, with the energy and the momentum transferred by the electron fixed at 840 MeV and 1502 MeV/c, ...respectively. The He-3(e,e(')p)H-2 cross section was measured for missing momenta up to 1000 MeV/c, while the A(TL) asymmetry was extracted for missing momenta up to 660 MeV/c. For missing momenta up to 150 MeV/c, the cross section is described by variational calculations using modern He-3 wave functions. For missing momenta from 150 to 750 MeV/c, strong final-state interaction effects are observed. Near 1000 MeV/c, the experimental cross section is more than an order of magnitude larger than predicted by available theories. The A(TL) asymmetry displays characteristic features of broken factorization with a structure that is similar to that generated by available models.
Image segmentation plays a major role in a broad range of applications. Evaluating the adequacy of a segmentation algorithm for a given application is a requisite both to allow the appropriate ...selection of segmentation algorithms as well as to tune their parameters for optimal performance. However, objective segmentation quality evaluation is far from being a solved problem. In this paper, a generic framework for segmentation evaluation is introduced after a brief review of previous work. A metric based on the distance between segmentation partitions is proposed to overcome some of the limitations of existing approaches. Symmetric and asymmetric distance metric alternatives are presented to meet the specificities of a wide class of applications. Experimental results confirm the potential of the proposed measures.
The implementation of fast dedicated processor for block matching motion estimation based on cumulants matching criteria implies the optimization of all of its components. Special care should be ...spent with the multiply-accumulate unit that is the core of many digital signal processing systems. Therefore, its optimization may be of outmost importance, specially if a significative number of such units are present in the platform. In this paper, the minimization of the size of one such unit is provided for a specific application, although the results have relevance in other scenarios.
Longitudinal joint cracking is one of the most prevalent forms of distress in asphalt concrete pavements. The joint area does not achieve the same density as the mat because of an unconfined edge on ...the initial pass and a cold joint during the second pass. The lower density allows water to penetrate, and the material cracks, usually within a year of construction. There are many techniques for constructing longitudinal joints; one is to preheat the joint before paving the second lane. A field study conducted in New Hampshire used an infrared joint heater on the base, binder, and surface layers of a full-depth hot-mix asphalt pavement. Thermocouples were embedded in the pavement to determine the extent of heat penetration from the infrared heaters. Cores were taken along the joint and in the travel lanes for both control and infrared test sections. Density and strength measurements taken on the cores show some statistically significant improvements in the joint constructed by using the infrared heater. Permeability measurements along the control and test joints were performed and show average differences between the two sections. Cracking surveys on the binder and surface layers performed 1 year after construction showed that the section of pavement where the infrared heater was used has significantly less cracking than the control section.
Traditionally, monoxenous trypanosomatid protozoa are not believed to infect vertebrate cells. Using light and electron microscopy, we show that the monoxenous trypanosomatids Crithidia deanei and ...Herpetomonas roitmani are able to infect dermal mouse fibroblasts in vitro. We present experimental evidence of phagocytosis of these trypanosomatids, and demonstrate their survival in vertebrate cells. This paper raises the question about the role of C. deanei and H. roitmani, and perhaps other monoxenous trypanosomatid species, in opportunistic infections of immunocompromised individuals and cutaneos lesions in vertebrate hosts.
Disclosure of the diagnosis of cancer to the patients affected has always been a controversial issue in the doctor-patient relationship. Undoubtedly this is so not only because of differences between ...countries and cultures, but also because there have been changes of opinion over the years. The aim of this study was to evaluate the quality and quantity of information desired by Portuguese cancer patients, and how and from whom they want to hear this information. Our sample comprised a total of 193 cancer patients, 87 men and 106 women. We found that 68.9% knew what their diagnosis was. In our sample, 74% wanted "as much information as possible, good or bad"; 85% said they wanted to know if their disease was cancer; 95% wanted to know the best or worst likely outcome of their disease; and 96.4% wanted to know the chances of getting cured. Most patients said they would prefer to be informed by physicians (92.7%) and have access to a telephone help-line, books and television. In conclusion, most patients wanted to know as much as possible about their illness and treatment, and the majority preferred to be involved in treatment decisions.
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