Pedro Quelhas Brito

The relevance of defining trace metal baselines in coastal waters at a regional scale: the case of the Portuguese coast (SW Europe).

The Water Framework Directives aims a reduction in concentration of hazardous substances in the marine environment. Consequently, there is a need to distinguish between anthropogenically influenced metal concentrations from natural background levels. To better achieve this goal in the Portuguese coast, dissolved and particulate trace metal (TM) concentrations along the Portuguese coast were determined in 46 sites distance 1-3 km from the shoreline. Dissolved values ranged within the following intervals: 0.01-0.89 nM for Cd, 0.01-3.37 nM for Co, 0.90-45.4 nM for Cu, 3.30-140 pM for Hg, 1.88-15.1 nM for Ni, 0.01-0.15 nM for Pb and 1.40-62.0 nM for Zn. Whereas Cd, Co, Cu, Ni and Zn were enhanced in the southern coast, while Pb values were higher in the central part of the western coast. Mercury concentrations showed punctual increases all along the coast. Values of trace metals in suspended particulate matter varied in a broad range: 36-2902 μmol g(-1) for Al, 0.10-15.1 nmol g(-1) for Cd, 1.50-165 nmol g(-1) for Co, 50.0-990 nmol g(-1) for Cu, 2.80-76.4 nmol g(-1) for Hg, 22-1471 nmol g(-1) for Ni, 10.0-347 nmol g(-1) for Pb and 416-10,981 nmol g(-1) for Zn. Higher values for Al, Ni and Co were found in the central part of the western coast. However, Cd, Cu, Pb and Zn increased their levels from the north coast towards the central and south areas. The variability of both dissolved and particulate metals appears to be mainly associated with oceanographic conditions and continental inputs at North and central areas of the coast, and in the south coast to geological features rather than to anthropogenic pressures. On the basis of these results, regional baseline concentrations are proposed for the three typologies in Portuguese coastal waters defined under the Water Framework Directive.

Spectral-Domain Optical Coherence Tomography Features of Acute Syphilitic Posterior Placoid Chorioretinitis: The Role of Autoimmune Response in Pathogenesis

Purpose: Syphilis is an infectious disease that can cause a wide variety of ocular signs. One of the rarest manifestations of ocular syphilis is acute syphilitic posterior placoid chorioretinitis (ASPPC). We report on the spectral-domain optical coherence tomography (SD-OCT) features of a case diagnosed with unilateral ASPPC. Methods: A 64-year-old man presented with a sudden loss of visual acuity (VA) in the right eye. His only clinical sign was a large, geographic, yellow-white lesion centered on the right fovea. Our patient was studied with SD-OCT on presentation and during follow-up, as well as with fluorescein and indocyanine green angiography, electrophysiological study, and serologic and autoimmune screening. Results: Laboratory workup revealed positive serology for active syphilis and elevated anti-beta2 glycoprotein I antibodies. SD-OCT showed a marked distortion of both the choroidal and outer retinal architecture. After treatment, best-corrected VA improved to 20/25. Pattern electroretinography displayed a severe reduction of P50 amplitude, which improved in late follow-up. Six months after presentation, VA was 20/25 and anti-beta2 glycoprotein I antibodies returned to normal levels. Conclusions: Our findings are compatible with immunologically mediated temporary physiological impairment of the neuroretina, since the changes seen by SD-OCT could not have normalized if they were due to anatomical injury. The results of our study provide clues to understanding the pathogenesis of this disease and allow us to define a characteristic temporal sequence of events in ASPPC.

Spectral-domain optical coherence tomography of the choroid during valsalva maneuver.

PURPOSE To evaluate the influence of Valsalva maneuver on the morphology and thickness of the choroid at the macular area. DESIGN Prospective interventional case series. METHODS Institutional setting. Nine healthy volunteers performed macular spectral-domain optical coherence tomography using enhanced-depth imaging at rest and during a Valsalva maneuver. Horizontal and vertical B-scans centered on the fovea were acquired. Subfoveal and average choroidal thickness in the central 3 mm were compared in the resting position and during the Valsalva maneuver using manual and semiautomatic measuring tools. Changes in choroidal thickness were evaluated. RESULTS There was no statistically significant difference in choroidal thickness at rest or during Valsalva maneuver in any of the compared groups. The subfoveal thickness difference was -4.1 μm on horizontal scans (P = .28) and 1.4 μm on vertical scans (P = .75). The mean choroidal thickness difference in the central 3000 μm was 8.5 μm on horizontal scans (P = .73) and -5.3 μm on vertical scans (P = .41). CONCLUSIONS Valsalva maneuver does not change choroidal thickness at the posterior pole. The increase in ocular pressure caused by this maneuver cannot be explained by an increase in choroidal thickness in this portion of the uveal tract.

Tweens' characterization of digital technologies

The tweens are a transitional age group undergoing deep physical and psychological transformations. Based on a thirteen-focus group research design involving 103 students, and applying a tweens-centered approach, the characteristics of SMS, IM, Internet, digital photos, electronic games, and email were analyzed. Categories such as moral issues, psychological and social consequences, problems/drawbacks, general benefits, and technical attributes synthesized the main characteristics attached to each form of digital technology. Their relative relevance was not gender dependent. Furthermore, tweens exhibited both metacognitive knowledge and personal epistemological observations associated with most of the digital technologies.

Shopping centre image dynamics of a new entrant

Purpose – The purpose of this paper is to investigate how and to what extent the attributes of a new shopping centre entrant evolve during the first seven months of operation, and the implications this has for the incumbents. To capture the strategic relevance of those changes a consumer image tracking analytical tool is developed and applied.Design/methodology/approach – Qualitative research followed by a longitudinal survey. Hypothesis testing approach and descriptive analysis.Findings – The correlates between the magnitudes of shopping centre attribute perception variations, the level of self‐confidence in image evaluation, shopping centre frequency of visits, degree of the “halo effect”, shopping centre and store consumers preferences are analysed. Only the self‐confidence and store preference did not evolve with the image magnitude changes as hypothesised.Research limitations/implications – The assessment of shopping centre image changes over time, as well as the factors underlying those changes hel...

Do open day events develop art museum audiences

For museums, developing audiences means both attracting non-visitors to their venues, and improving repeat visitors’ attendance patterns and experience. Audience development strategies encourage museums to create open door events in order to deal with barriers preventing a wider audience from becoming their visitors, and to build stronger relationships with their current visitors. Satisfaction is expected to influence future buying decisions – i.e., intention to return and to recommend. Will a satisfying experience at a museum event improve event goers’ visiting patterns? This research aims to ascertain the effects of attending open day events on the development of art museum audiences. We present the findings of exploratory quantitative research using the personal interview survey method. Our results indicate that open day events have potential to develop audiences, as such events eliminate attendance barriers, attract first time visitors and provide trial experiences for potential museum visitors. However, the positive association between event experience and intention to return to the museum on an ordinary day was not statistically supported by this study.

Teen conceptualization of digital technologies

This research explores teenagers’ knowledge representation of six digital technologies – email, IM, internet, digital photos, sms and games. Instead of pre-imposing a specific structure, teens freely express everything they consider relevant by identifying the meanings associated with each digital technology. Drawing on cognitive psychology theories and teenagers’ social development theories, the data from thirteen focus groups were analyzed. The nature of attributes comprising technical features, personal and socially relevant activities/experiences, feelings and attitudes towards these instruments only partially matched other IT conceptualizations. However, those studies applied different methodological approaches. Among the 133 attributes suggested, 30 were shared by at least two digital technologies. The Multiple Correspondence Analysis showed that games were psychologically and functionally (physical attributes) more integrated with IM and internet whereas digital photos were segregated. The communicational and product design implications of assessing attributes are discussed.

Factor Analysis to Support the Visualization and Interpretation of Clusters of Portal Users

Clusterings based on many variables are difficult to visualize and interpret. We present a methodology based on factor analysis (FA) which can be used for that purpose. FA generates a small set of variables which encode most of the information in the original variables. We apply the methodology to segment the users of a Web portal, using access log data. It not only makes it simpler to visualize and understand the clusters which are obtained on the original variables but it also helps the analyst in selecting some of the original variables for further analysis of those clusters

Insights of Pb isotopic signature into the historical evolution and sources of Pb contamination in a sediment core of the southwestern Iberian Atlantic shelf

Stable Pb isotopic ratios and concentrations of Al, Cu and Pb were measured in a 5m long sediment core (VC2B) retrieved at 96m water depth in the southwestern Iberian Atlantic shelf. Five phases during the last 9.5kyrs were identified, two of them (Roman Period and modern mining) marked by a decrease of 206Pb/207Pb ratios reflecting additional inputs of Pb derived from mining activities. The Roman Period was also characterized by high 208Pb/206Pb ratios suggesting the exploitation of the outcropping portion of the orebody intensely weathered when compared with the other formations later mined. The shift of 208Pb/206Pb ratios towards linearity took approximately 1.0kyrs, which may mirror the time of environmental recovery from the impact of Roman mining activities. The application of a mixing model allowed the quantification of the contribution associated with anthropogenic mining activities to the shelf sediments. The maximum values of Pb contamination occurred in the 20th century. This study gives direct evidence of Pb and Cu exploitation over the last 2000years. The stable Pb isotopic signatures point to legacy of mining activities that are still the prevailing metal source recorded in the southwestern Iberian Atlantic shelf sediments.

Comparison of consumer purchase intention between interactive and augmented reality shopping platforms through statistical analyses

The objective of this study is to explore the effectiveness of three digital shopping platforms (Plain Interactive, Marker-based Augmented Reality and Markerless Augmented Reality), on the impressions and purchase intentions of consumers. The study is mainly interested in analysing whether intelligent shopping platforms with AR elements provide any added advantage to an advertised product in the form of favourable attitude or a stronger purchase impulse. During the tests with the three shopping platforms, quantitative data was collected via computerised questionnaire. High and Low class users were statistically extracted, corresponding to the high or low probability to buy or recommend the advertised brand. The results show that Markerless AR system clearly outperforms the Marker-based AR and the Plain Interactive in terms of positive attitude from the users. The second better performing system is the Marker-based AR, which closely follows the Markerless AR, while the Plain Interactive system obtains least approval.