1,655 research outputs found

    Modelling human factors in perceptual multimedia quality: On the role of personality and culture

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    Perception of multimedia quality is shaped by a rich interplay between system, context, and human factors. While system and context factors are widely researched, few studies in this area consider human factors as sources of systematic variance. This paper presents an analysis on the influence of personality (Five-Factor Model) and cultural traits (Hofstede Model) on the perception of multimedia quality. A set of 144 video sequences (from 12 short movie excerpts) were rated by 114 participants from a cross-cultural population, producing 1232 ratings. On this data, three models are compared: a baseline model that only considers system factors; an extended model that includes personality and culture as human factors; and an optimistic model in which each participant is modeled as a random effect. An analysis shows that personality and cultural traits represent 9.3% of the variance attributable to human factors while human factors overall predict an equal or higher proportion of variance compared to system factors. In addition, the quality-enjoyment correlation varied across the movie excerpts. This suggests that human factors play an important role in perceptual multimedia quality, but further research to explore moderation effects and a broader range of human factors is warranted

    Brood patch and sex-ratio observations indicate breeding provenance and timing in New Zealand storm petrel (Fregetta maoriana)

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    We used measurements of brood patch and moult status to estimate the breeding phenology of New Zealand Storm-Petrel, using birds caught at sea within the Hauraki Gulf Marine Park near Auckland, New Zealand. Birds caught October–January had completely downy brood patches, whereas birds caught February–April had bare brood patches with an observed male bias in the February sex-ratio, consistent with a female pre-laying exodus typical of petrels and with the existence of an unknown colony in the region. No birds captured exhibited primary moult, which is known to occur in storm-petrels during their non-breeding season. Our data support the conclusion that the New Zealand storm-petrel breeds during January–June in northern New Zealand and that field surveys for the species on offshore islands in this region during this period are warrante

    The effect of Co and Zn addition on densification and electrical properties of ceria-based nanopowders

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    CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORIn this work, cobalt and zinc-doped Ce0.8Gd0.2O1.9 samples were prepared starting from a commercial nanopowder and compared to the undoped material. The powder samples were pressed and afterwards sintered by a two-step procedure, before characterization by X-Ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Impedance Spectroscopy (IS) in air. Cobalt or zinc additions are effective as sintering aid, allowing peak sintering temperatures around 1000 degrees C to reach densifications above of 93% of theoretical density, showing no evidence for the presence of secondary phases. The total conductivity at 800 degrees C of pressed Zn-doped samples (6.7x10(-2) S/cm) and Co-doped samples (7.5x10(-2) S/cm) is similar for undoped samples (7.2x10(-2) S/cm) showing that Zn and Co has a positive effect on densification without compromising the electrical conductivity.In this work, cobalt and zinc-doped Ce0.8Gd0.2O1.9 samples were prepared starting from a commercial nanopowder and compared to the undoped material. The powder samples were pressed and afterwards sintered by a two-step procedure, before characterization by X-Ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Impedance Spectroscopy (IS) in air. Cobalt or zinc additions are effective as sintering aid, allowing peak sintering temperatures around 1000 degrees C to reach densifications above of 93% of theoretical density, showing no evidence for the presence of secondary phases. The total conductivity at 800 degrees C of pressed Zn-doped samples (6.7x10(-2) S/cm) and Co-doped samples (7.5x10(-2) S/cm) is similar for undoped samples (7.2x10(-2) S/cm) showing that Zn and Co has a positive effect on densification without compromising the electrical conductivity.19510571063CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORSem informaçãoSem informaçãoFinancial supports from CAPES and CNPq are greatly appreciated. We would like to thank Rita C. G. Vinhas (State University of Campinas, Campinas Campus, Brazil), for helping with the XPS measurements

    The DRIFT Dark Matter Experiments

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    The current status of the DRIFT (Directional Recoil Identification From Tracks) experiment at Boulby Mine is presented, including the latest limits on the WIMP spin-dependent cross-section from 1.5 kg days of running with a mixture of CS2 and CF4. Planned upgrades to DRIFT IId are detailed, along with ongoing work towards DRIFT III, which aims to be the world's first 10 m3-scale directional Dark Matter detector.Comment: Proceedings of the 3rd International conference on Directional Detection of Dark Matter (CYGNUS 2011), Aussois, France, 8-10 June 201

    Intraoperative frozen section assessment of sentinel lymph nodes in the operative management of women with symptomatic breast cancer

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    <p>Abstract</p> <p>Background</p> <p>Maximisation of the potential of sentinel lymph node biopsy as a minimally invasive method of axillary staging requires sensitive intraoperative pathological analysis so that rates of re-operation for lymphatic metastases are minimised. The aim of this study was to describe the test parameters of the frozen section evaluation of sentinel node biopsy for breast cancer compared to the gold standard of standard permanent pathological evaluation at our institution.</p> <p>Methods</p> <p>The accuracy of intraoperative frozen section (FS) of sentinel nodes was determined in 94 consecutive women undergoing surgery for clinically node negative, invasive breast cancer (37:T1 disease; 43:T2; 14:T3). Definitive evidence of lymphatic spread on FS indicated immediate level II axillary clearance while sentinel node "negativity" on intraoperative testing led to the operation being curtailed to allow formal H&E analysis of the remaining sentinel nodal tissue.</p> <p>Results</p> <p>Intraoperative FS correctly predicted axillary involvement in 23/30 patients with lymphatic metastases (76% sensitivity rate) permitting definitive surgery to be completed at the index operation in 87 women (93%) overall. All SN found involved on FS were confirmed as harbouring tumour cells on subsequent formal specimen examination (100% specificity and positive predictive value) with 16 patients having additional non-sentinel nodes found also to contain tumour. Negative Predictive Values were highest in women with T1 tumours (97%) and lessened with more local advancement of disease (T2 rates: 86%; T3: 75%). Of those with falsely negative FS, three had only micrometastatic disease.</p> <p>Conclusion</p> <p>Intraoperative FS reliably evaluates the status of the sentinel node allowing most women complete their surgery in a single stage. Thus SN can be offered with increased confidence to those less likely to have negative axillae hence expanding the population of potential beneficiaries.</p

    Hafnium silicide formation on Si(100) upon annealing

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    FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORHigh dielectric constant materials, such as HfO2, have been extensively studied as alternatives to SiO2 in new generations of Si based devices. Hf silicate/silicide formation has been reported in almost all literature studies of Hf based oxides on Si, using different methods of preparation. A silicate interface resembles close to the traditional Si/SiO2. The silicate very likely forms a very sharp interface between the Si substrate and the metal oxide, and would be suitable for device applications. However, the thermal instability of the interfacial silicate/oxide film leads to silicidation, causing a dramatic loss of the gate oxide integrity. Despite the importance of the Hf silicide surface and interface with Si, only a few studies of this surface are present in the literature, and a structural determination of the surface has not been reported. This paper reports a study of the Hf silicide formation upon annealing by using a combination of XPS, LEED, and x-ray photoelectron diffraction (XPD) analyses. Our results clearly indicate the formation of a unique ordered Hf silicide phase (HfSi2), which starts to crystallize when the annealing temperature is higher than 550 °C.High dielectric constant materials, such as HfO2, have been extensively studied as alternatives to SiO2 in new generations of Si based devices. Hf silicate/silicide formation has been reported in almost all literature studies of Hf based oxides on Si, using different methods of preparation. A silicate interface resembles close to the traditional Si/SiO2. The silicate very likely forms a very sharp interface between the Si substrate and the metal oxide, and would be suitable for device applications. However, the thermal instability of the interfacial silicate/oxide film leads to silicidation, causing a dramatic loss of the gate oxide integrity. Despite the importance of the Hf silicide surface and interface with Si, only a few studies of this surface are present in the literature, and a structural determination of the surface has not been reported. This paper reports a study of the Hf silicide formation upon annealing by using a combination of XPS, LEED, and x-ray photoelectron diffraction (XPD) analyses. Our results clearly indicate the formation of a unique ordered Hf silicide phase (HfSi2), which starts to crystallize when the annealing temperature is higher than 550 °C.747110FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORSem informaçãoSem informação170/04This work was financially supported by DAAD (PROBRAL D/03/23553) from Germany, and FAPESP, CNPq, and CAPES (PROBRAL 170/04) from Brazil. A.S. especially would like to thank CAPES for their support

    Iterative Learning Control of Single Point Incremental Sheet Forming Process using Digital Image Correlation

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    Single Point Incremental Sheet Forming (SPIF) is a versatile forming process that has gained significant traction over the past few decades. Its increased formability, quick part adaption, and reduced set-up costs make it an economical choice for small batch and rapid prototype forming applications when compared to traditional stamping processes. However, a common problem with the SPIF process is its tendency to produce high geometric error due to the lack of supporting dies and molds. While geometric error has been a primary focus of recent research, it is still significantly larger for SPIF than traditional forming processes. In this paper, the convergence behavior and the ability to reduce geometric error using a simple Iterative Learning Control (ILC) algorithm is studied with two different forming methods. For both methods a tool path for the desired reference geometry is generated and a part is formed. A Digital Image Correlation (DIC) system takes a measurement and the geometric error along the tool path is calculated. The ILC algorithm then uses the geometric error to alter the tool path for the next forming iteration. The first method, the Single Sheet Forming (SSF) method, performs each iteration on the same sheet. The second method, the Multi Sheet Forming (MSF) method, performs each iteration on a newly replaced sheet. Multiple experiments proved the capability of each method at reducing geometric error. It was concluded that using the MSF method allows for negative corrections to the forming part and, therefore, leads to better final part accuracy. However, this method is less cost effective and more time consuming than using the standard SSF methodology. In addition, it was found that in order to effectively correct a part with an ILC algorithm, steps must be taken to increase the controllability of the part geometry
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