Patterson Function from Low-Energy Electron Diffraction Measured Intensities and Structural Discrimination

Surface Patterson Functions have been derived by direct inversion of experimental Low-Energy Electron Diffraction I-V spectra measured at multiple incident angles. The direct inversion is computationally simple and can be used to discriminate between different structural models. 1x1 YSi_2 epitaxial layers grown on Si(111) have been used to illustrate the analysis. We introduce a suitable R-factor for the Patterson Function to make the structural discrimination as objective as possible. From six competing models needed to complete the geometrical search, four could easily be discarded, achieving a very significant and useful reduction in the parameter space to be explored by standard dynamical LEED methods. The amount and quality of data needed for this analysis is discussed.Comment: 5 pages, 4 figure

Friction Stir Welding Of Duplex And Superduplex Stainless Steels And Some Aspects Of Microstructural Characterization And Mechanical Performance

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Friction stir welding was used to produce butt joints on 6 mm thick plates of UNS S32101 lean duplex stainless steel, S32205 duplex stainless steel, and S32750 and S32760 superduplex stainless steels. Fully consolidated joints were achieved, with full penetration, using heat input of 1.37-1.50 kJ/mm. Specimens submitted to tensile testing performed perpendicular to the welding direction showed failure on the base metal, reflecting better mechanical performance of the welded joints. Furthermore, tensile testing along the joints revealed higher yield and tensile strengths in all cases, as well as increased elongation. Microstructural evaluation showed that there was pronounced grain refinement in the welded joints of all the materials studied, achieving grain sizes as small as 1 mu m. The differences in the ferrite and austenite grain sizes in the stir zone, such as the degree of grain refinement, could be explained by the combination of dynamic recrystallization of austenite during the welding process and the recrystallization and growth of the ferrite grains, promoted firstly by the severe deformation and secondly by the high temperature inherent to the FSW process. Superduplex stainless steel FSW joints were more able to maintain a balanced microstructure, compared to conventional and lean duplex stainless steels, due to greater homogeneity of recrystallization in the welded joint.191117131PetrobrasFINEPCNPqFAPESPConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Indigo (Cat5 & Sep5) System mechanical thrombectomy for acute mesenteric ischemia: an innovative approach for treatment of a severe but not so infrequent disease

Acute Mesenteric ischemia (AMI) is a severe and commonly underreported disease that has an annual incidence of 0.09-0.2% per patient year. However some studies have shown an increased incidence of AMI after performing an exhaustive analysis of 402 autopsies and surgeries (1970-1982 Malmo, Sweden). All mesenteric ischemia (MI) has and incidence of 12.9 cases of MI/10000 inhabitants/year, 67% thromboembolic SMA occlusion, 16% mesenteric venous thrombosis (MVT), 15% non-occlusive mesenteric ischemia (NOMI) and 2% have indeterminate cause. We present a patient with SMA treated satisfactorily with a new thromboaspiration system

A Simple Gaze Tracker for Computer Operation by the Disabled in Education

A compact gaze tracker was developed which consists of a head band and electrodes which process the Electro-Oculo-Gram (EOG) reflecting the patient´s eye movements. We have confirmed that the processed EOG signal correlates well with gaze angle, and we show that the instrument we designed enables a child to move a target on a screen up to 40 degrees left-right from central sight. To achieve this, a signal processing circuit was designed and placed on a head band to minimize noise. Further processing is based on the identification of saccadic eye movements and on the educated calculation of the estimated gaze angle as a result of angle change in both directions. A 75% success rate was achieved to detect transitions of eye positions in 5° steps from +40° to -40°. First tests by normal children suggest that the device may prove useful for communication by the disabled (e.g. patients with no control on hand movements). In such cases, extensive personal training will tap on neurological plasticity to achieve the required performance level for computer mouse command of educational games and for interactive applications in general

JAMAICA IN THE AGE OF DEVELOPMENT: PETITIONS, SMALL FARMING, AND AGRICULTURAL PLANNING, 1895-1972

This dissertation analyses the development models pursued in Jamaica from 1895 to 1972. It is concerned with three lines of inquiry throughout different historical junctures from the late nineteenth century to the late 1960s. To what extent did colonial and post-colonial ideas around the peasantry’s role within the island’s economic development change over the course of the twentieth century? In what ways did the colonial and national development policies, drafted throughout the different historical junctures, reflect those changing ideas? Whose voices were heard and whose needs were met in the articulation of the policies on the ground? By reconstructing the evolving models of development in the island, this dissertation illustrates the significant role of small and middle-sized growers, tenants, and agricultural laborers in the political process. Based on records from the Jamaican National Archives in Spanish Town, the U.S. National Archives, official government reports, and contemporary newspapers and journals, I map how the visibility and salience of each of these groups changed over time. I contend that these rural inhabitants shaped island-wide development visions and rhetoric in Jamaican society. Building on recent literature on international development, I also demonstrate how the participation of various political, social, and economic actors in small-scale, bottom-up spaces helped define the outcomes and subsequent transformations of colonial and post-colonial development agendas. I conclude that ‘development’ was not a top-down process formulated abroad and applied in Jamaica, rather that actors on the ground in the island molded colonial and national development over time

Hotel assessment through social media: The case of TripAdvisor

Hotel booking decisions are increasingly influenced by consumer feedback available on social media sites. Using data submitted by customers on TripAdvisor, this study analyzes the customer satisfaction ratings posted for 2,211 hotels. The study provides four key contributions to our knowledge on this subject. Firstly, a comparative analysis was conducted of customer ratings for hotels located on the Spanish coast and Portugal's southern coast. Secondly, significant differences were found in the number of comments and average online review ratings, which showed a correlation to the tourism destinations’ geographical locations. Thirdly, the study found that customers tend to rate their hotel experiences positively. Fourthly, the customers' overall level of satisfaction with a hotel tends to increase proportionately based on the number of customer feedback comments posted for that hotel. Consequently, one of this study's findings is that hotels should encourage their customers to post comments on customer review websites to balance out any negative feedback

Design of a compact objective for SWIR applications

Lately the short-wave infrared (SWIR) has become very important due to the recent appearance on the market of the small detectors with a large focal plane array. Military applications for SWIR cameras include handheld and airborne systems with long range detection requirements, but where volume and weight restrictions must be considered. In this paper we present three different designs of telephoto objectives that have been designed according to three different methods. Firstly the conventional method where the starting point of the design is an existing design. Secondly we will face design starting from the design of an aplanatic system. And finally the simultaneous multiple surfaces (SMS) method, where the starting point is the input wavefronts that we choose. The designs are compared in terms of optical performance, volume, weight and manufacturability. Because the objectives have been designed for the SWIR waveband, the color correction has important implications in the choice of glass that will be discussed in detai