Showing papers by "University of Madeira published in 2009"

Bioinspired superhydrophobic poly(L‐lactic acid) surfaces control bone marrow derived cells adhesion and proliferation

Abstract: The aptitude of a cell to adhere, migrate, and differentiate on a compact substrate or scaffold is important in the field of tissue engineering and biomaterials. It is well known that cell behavior can be controlled and guided through the change in micro- and nano-scale topographic features. In this work, we intend to demonstrate that special topographic features that control wettability may also have an important role in the biological performance of biodegradable substrates. Poly(L-lactic acid) surfaces with superhydrophobic characteristics were produced, based on the so-called Lotus effect, exhibiting dual micro- and nano-scale roughness. The water contact angle could be higher than 150° and a value of that order could be kept even upon immersion in a simulated body fluid solution for more than 20 days. Such water repellent surfaces were found to prevent adhesion and proliferation of bone marrow derived cells previously isolated from the femurs of 6-week-old male Wistar rats, when compared with smoother surfaces prepared by simple solvent casting. Such results demonstrate that these superhydrophobic surfaces may be used to control cell behavior onto biodegradable substrates. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009

Characterization of volatile substances in apples from Rosaceae family by headspace solid‐phase microextraction followed by GC‐qMS

Abstract: The volatile composition of different apple varieties of Malus domestica Borkh. species from different geographic regions at Madeira Islands, namely Ponta do Pargo (PP), Porto Santo (PS), and Santo da Serra (SS) was established by headspace solid-phase microextraction (HS-SPME) procedure followed by GC-MS (GC-qMS) analysis. Significant parameters affecting sorption process such as fiber coating, extraction temperature, extraction time, sample amount, dilution factor, ionic strength, and desorption time, were optimized and discussed. The SPME fiber coated with 50/30 microm divinylbenzene/carboxen/PDMS (DVB/CAR/PDMS) afforded highest extraction efficiency of volatile compounds, providing the best sensitivity for the target volatiles, particularly when the samples were extracted at 50 degrees C for 30 min with constant magnetic stirring. A qualitative and semi-quantitative analysis between the investigated apple species has been established. It was possible to identify about 100 of volatile compounds among pulp (46, 45, and 39), peel (64, 60, and 64), and entire fruit (65, 43, and 50) in PP, PS, and SS apples, respectively. Ethyl esters, terpenes, and higher alcohols were found to be the most representative volatiles. Alpha-farnesene, hexan-1-ol and hexyl 2-methylbutyrate were the compounds found in the volatile profile of studied apples with the largest GC area, representing, on average, 24.71, 14.06, and 10.80% of the total volatile fraction from PP, PS, and SS apples. In PP entire apple, the most abundant compounds identified were alpha-farnesene (30.49%), the unknown compound m/z (69, 101, 157) (21.82%) and hexyl acetate (6.57%). Regarding PS entire apple the major compounds were alpha-farnesene (16.87%), estragole (15.43%), hexan-1-ol (10.94), and E-2-hexenal (10.67). Alpha-farnesene (30.3%), hexan-1-ol (18.90%), 2-methylbutanoic acid (4.7%), and pentan-1-ol (4.6%) were also found as SS entire apple volatiles present in a higher relative content. Principal component analysis (PCA) of the results clustered the apples into three groups according to geographic origin. Linear discriminant analysis (LDA) was performed in order to detect the volatile compounds able to differentiate the three kinds of apples investigated. The most important contributions to the differentiation of the PP, PS, and SS apples were ethyl hexanoate, hexyl 2-methylbutyrate, E,E-2,4-heptadienal, p-ethyl styrene, and E-2-hexenal.

Ecological assessment of an intermittent Mediterranean river using community structure and function: evaluating the role of different organism groups.

Abstract: SUMMARY 1. Reliable lotic ecological monitoring requires knowledge of river typology, environmental factors, the effect of stressors known here as ‘pressures’ and appropriate indicators of anthropogenically induced change. We sampled benthic macroinvertebrate, fish, bird and macrophyte communities along an intermittent Mediterranean river and analysed community structure (relative abundance) and function (metrics) relative to environmental and pressure gradients in order to identify suitable indicator group(s) for future monitoring and mitigation programmes. 2. Principal components analysis revealed that scale-dependent longitudinal differences in valley form separated narrower higher lying sites and tributaries with good quality habitats from more open degraded sites lower down the river continuum on a small floodplain and large scale pressures describing changes in land use related to agriculture with associated physical bankside and channel impacts. 3. Forward selection of variables in redundancy analysis (RDA) showed that reach scale environmental variables were selected more frequently than pressure variables for each organism group. Altitude and pH were highly redundant within and between groups, indicating essentially longitudinal structural and functional distribution patterns. Redundancy was far lower between selected pressure variables, but single or no pressure variables were retained for some organism groups indicating poor association of functional data, in particular, with the identified pressures. All RDA results indicated a longitudinal pH gradient, highlighting the combined effect of multiple environmental and pressure based mechanisms on organism groups. 4. Large, mobile organisms such as fish and birds provided a reliable link between organism structure and function, environmental factors and physical disturbance of the channel, bankside and wider river corridor. Benthic macroinvertebrate and macrophyte structural data revealed distribution patterns in relation to water velocity, a key parameter for developing appropriate compensation measures. 5. Results clearly show the importance of assessing patterns of both functional and structural change across multiple organism groups in order to identify typologically

Raman fibre Bragg-grating laser sensor with cooperative Rayleigh scattering for strain?temperature measurement

Abstract: In this work, a Raman fibre Bragg-grating laser sensor for strain–temperature measurement is presented. The laser resonator is a linear cavity formed by the reflectivity of the Bragg gratings and the virtual distributed mirror formed from the cooperative Rayleigh scattering in a dispersion-compensating fibre created by the Raman effect. Using one pump laser it is possible to obtain a Raman fibre Bragg-grating laser sensor with a range of ~35 nm. The sensing system is demonstrated when the fibre Bragg gratings are remotely located at a 10 km distance.

A Framework for Haptic Broadcasting

Abstract: This article presents a comprehensive exploration of the issues underlying haptic multimedia broadcasting. It also describes the implementation of a prototype system as a proof of concept.

Is the Crowd's Wisdom Biased? A Quantitative Analysis of Three Online Communities

Abstract: —We present a study of user voting on three websites: Imdb, Amazon and BookCrossings. Here we report on an expert evaluation of the voting mechanisms of each website and a quantitative data analysis of users’ aggregate voting behavior. Our results suggest that the websites with higher barrier to vote introduce a relatively high number of one-off voters, and they appear to attract mostly experts. We also find that one-off voters tend to vote on popular items, while experts mostly vote for obscure, low-rated items. We conclude with design suggestions to address the “wisdom of the crowd” bias.

Human activity modeling: toward a pragmatic integration of activity theory and usage-centered design

Abstract: Human activity modeling is a systematic approach to organizing and representing the contextual aspects of tool use that is both well-grounded in an accepted theoretical framework and embedded within a proven design method. Activity theory provides the vocabulary and conceptual framework for understanding the human use of tools and other artifacts. Usage-centered design provides the methodological scaffolding for applying activity theory in practice. In this chapter, activity theory and usage-centered design are outlined and the connections between the two are highlighted. Simple extensions to the models of usage-centered design are introduced that together succinctly model the salient and most essential features of the activities within which tool use is embedded. Although not intended as a tutorial, examples of Activity Maps, Activity Profiles, and Participation Maps are provided.

Analysis of phenolic compounds from different morphological parts of Helichrysum devium by liquid chromatography with on-line UV and electrospray ionization mass spectrometric detection

Abstract: A simple and rapid method has been used for the screening and identification of the main phenolic compounds from Helichrysumdevium using high-performance liquid chromatography with on-line UV and electrospray ionization mass spectrometric detection (LC-DAD/ESI-MSn). The total aerial parts and different morphological parts of the plant, namely leaves, flowers and stems, were analyzed separately. A total of 34 compounds present in the methanolic extract from Helichrysumdevium were identified or tentatively characterized based on their UV and mass spectra and retention times. Three of these compounds were positively identified by comparison with reference standards. The phenolic compounds included derivatives of quinic acid, O-glycosylated flavonoids, a caffeic acid derivative and a protocatechuic acid derivative. The characteristic loss of 206 Da from malonylcaffeoyl quinic acid was used to confirm the malonyl linkage to the caffeoyl group. This contribution presents one of the first reports on the analysis of phenolic compounds from Helichrysumdevium using LC-DAD/ESI-MSn and highlights the prominence of quinic acid derivatives as the main group of phenolic compounds present in these extracts. We also provide evidence that the methanolic extract from the flowers was significantly more complex when compared to that of other morphological parts. Copyright © 2009 John Wiley & Sons, Ltd.

Simultaneous Measurement of Refractive Index and Temperature Using a Hybrid Fiber Bragg Grating/Long-Period Fiber Grating Configuration

Abstract: A fiber optic sensing system for simultaneous measurement of refractive index and temperature, based on a hybrid fiber Bragg grating/long-period grating arrangement is described. The experimental results show that this setup has a good performance in terms of linearity and sensitivity, the ratiometric output changes 4%/0.001 RIU and 3.6%/°C, respectively. The sensor resolution for the refractive index is ≈2 × 10−5 RIU. The simultaneous measurement of the refractive index and temperature was demonstrated. The sensing configuration has the ability to be read-out in reflection and works in the telecommunications window.

Vulnerabilidade ao stress, estratégias de coping e autoeficácia em professores portugueses

Abstract: In this work we present a research carried out on teachers to determine their vulnerability to stress, to identify the main sources of stress, to recognize teachers' main coping strategies, to analyze whether such strategies condition the presence of stress at work, and to establish whether the self-efficiency perceived can be used to predict work stress. This is a correlational questionnaire-based research performed on a 54-teacher sample from Portugal's public basic education schools. The answers to the Social, Demographic and Professional Questionnaire, to the Stress Vulnerability Questionnaire - 23QVS (Serra, 2000), to the Teacher Stress Questionnaire - QSP (Gomes et al., 2006; Gomes, 2007), to the Coping Job Scale - CJS (Latack, adapted by Jesus and Pereira, 1994) and to the General Self-efficiency Assessment Scale (Ribeiro, 1995) reveal that 20.4% of teachers are vulnerable to stress. The study shows that the main stress sources are found in students' lack of discipline or improper behaviour, and that control strategies are the most common to deal with stress, followed by escape strategies and symptom management. Teachers not vulnerable to stress use mainly control strategies and they display higher efficiency levels under adversity, as well as more initiative and perseverance than the teachers that are vulnerable to stress.

Motion marking menus: An eyes-free approach to motion input for handheld devices

Abstract: The increasing complexity of applications on handheld devices requires the development of rich new interaction methods specifically designed for resource-limited mobile use contexts. One appealingly convenient approach to this problem is to use device motions as input, a paradigm in which the currently dominant interaction metaphors are gesture recognition and visually mediated scrolling. However, neither is ideal. The former suffers from fundamental problems in the learning and communication of gestural patterns, while the latter requires continual visual monitoring of the mobile device, a task that is undesirable in many mobile contexts and also inherently in conflict with the act of moving a device to control it. This paper proposes an alternate approach: a gestural menu technique inspired by marking menus and designed specifically for the characteristics of motion input. It uses rotations between targets occupying large portions of angular space and emphasizes kinesthetic, eyes-free interaction. Three evaluations are presented, two featuring an abstract user interface (UI) and focusing on how user performance changes when the basic system parameters of number, size and depth of targets are manipulated. These studies show that a version of the menu system containing 19 commands yields optimal performance, compares well against data from the previous literature and can be used effectively eyes free (without graphical feedback). The final study uses a full graphical UI and untrained users to demonstrate that the system can be rapidly learnt. Together, these three studies rigorously validate the system design and suggest promising new directions for handheld motion-based UIs.

Exploring Digital Encounters in the Public Arena

Abstract: In this chapter, we explore the types of encounters that technology enables. We consider the differences between digital and nondigital encounters through two pilot studies carried out in the city of Bath, United Kingdom. We investigate how technology can be appropriated for shared interactions that support conscious (or unconscious) social encounters, and highlight the importance of space and the role of place in providing temporal and spatial mechanisms facilitating different types of shared encounters. Here, we apply a method based on intervention through “sensing and projecting” Bluetooth names and digital identity in the public arena, and describe initial observations about people’s reaction toward the projection of their Bluetooth names in public. In particular, we note the significance of constructing socially meaningful relations between people mediated by these technologies. We discuss initial results and outline issues raised in detail before finally describing the ongoing work.

Investigating near-anode plasma layers of very high-pressure arc discharges

Abstract: Numerical and experimental investigation of near-anode layers of very high-pressure arcs in mercury and xenon is reported. The simulation is performed by means of a recently developed numerical model in which the whole of a near-electrode layer is simulated in the framework of a single set of equations without simplifying assumptions such as thermal equilibrium, ionization equilibrium and quasi-neutrality and which was used previously for a simulation of the near-cathode plasma layers. The simulation results support the general understanding of similarities and differences between plasma–cathode and plasma–anode interaction in high-pressure arc discharges established in preceding works. In particular, the anode power input is governed primarily by, and is approximately proportional to, the arc current. In the experiment, the spectral radiance from the electrodes and the near-electrode regions in xenon arcs was recorded. The derived total anode power input and near-anode plasma radiance distribution agree reasonably well with the simulation results.

SIMUFLEX: Algorithms and Tools for Simulation of the Conformation and Dynamics of Flexible Molecules and Nanoparticles in Dilute Solution

Abstract: A computer programs suite, SIMUFLEX, has been constructed for the calculation of solution properties of flexible macromolecules modeled as bead-and-connector models of arbitrary topology. The suite consists mainly of two independent programs, BROWFLEX that generates the macromolecular trajectory by using the Brownian dynamics technique and ANAFLEX that analyzes that trajectory to get solution properties of the macromolecule. In this paper, we describe theoretical aspects about the macromolecular model and the Brownian dynamics algorithm used and describe some of the numerous properties that can be evaluated. In order to provide examples of the application of the methodology, we present simulations of dynamic properties of DNA with length ranging from 10 to 10 5 base pairs. SIMUFLEX is able to run simulations with more or less coarse-grained models, thus enabling such multiple-scale studies.

Superdotação: conceitos e modelos de diagnóstico e intervenção psicoeducativa

Abstract: The definition of Giftedness is not exempt from unreliability and controversy. The concept is not static, it is in constant evolution, being that the current trend is characterized by the balance of other variables beyond the cognitive and intelligence. According to the World Council for Gifted and Talented children, one can be considered gifted when exhibiting high performance or potential, in any of the following aspects in isolation or combined: general intellectual capacity, specific academic skill, creative or productive thinking, special talent for the visual, dramatic and musical arts, motor skills and capacity for leadership. Thus, the multiplicity of concepts ends up translating into a multiplicity of criteria that must be considered in the definition of giftedness, which means that assessment must also be multifaceted. As a result, a broad range of intervention proposals is required, as well as recourse to different agents, procedures and assessment instruments.

Toward the Design of Mutation‐Resistant Enzyme Inhibitors: Further Evaluation of the Substrate Envelope Hypothesis

Abstract: Previous studies have shown the usefulness of the substrate envelope concept in the analysis and prediction of drug resistance profiles for human immunodeficiency virus protease mutants. This study tests its applicability to several other therapeutic targets: Abl kinase, chitinase, thymidylate synthase, dihydrofolate reductase, and neuraminidase. For the targets where many (> or =6) mutation data are available to compute the average mutation sensitivity of inhibitors, the total volume of an inhibitor molecule that projects outside the substrate envelope V(out), is found to correlate with average mutation sensitivity. Analysis of a locally computed volume suggests that the same correlation would hold for the other targets, if more extensive mutation data sets were available. It is concluded that the substrate envelope concept offers a promising and easily implemented computational tool for the design of drugs that will tend to resist mutations. Software implementing these calculations is provided with the 'Supporting Information'.

Social calls are subject to stabilizing selection in insular bats

Abstract: Aim Bats communicate by emitting social calls, and these often elicit reactions in conspecifics. Many such vocalizations are species-specific so that unambiguous signals can be transmitted and interpreted by conspecifics. In species-rich assemblages, evolutionary pressures might prompt interspecific diversification of call structure so that communication with heterospecifics is avoided. In species-poor island communities, where no risk of miscommunication occurs, stabilizing selection should prevail and preserve call structure and function. Call structure in island bats might be inherited from colonizers from the mainland and be maintained with little change in the absence of selection from heterospecifics. To test this hypothesis we studied Pipistrellus maderensis, an insular taxon occurring on the Madeira Archipelago, the Canary Islands and the Azores. It is closely related to one of the most widespread European pipistrelles, Pipistrellus kuhlii. Pipistrellus maderensis most probably evolved from a common ancestor shared with P. kuhlii, or from founders of that taxon that colonized the islands. We hypothesized that on Madeira Island, where no risk of ambiguous communication with heterospecifics exists, the structure and function of social calls should have been preserved by stabilizing selection. Echolocation calls, subject to different selection pressures, may instead show more pronounced differences between P. maderensis and P. kuhlii. Location Madeira Island (Portugal, Atlantic Ocean), central and southern Italy. Methods We recorded social and echolocation calls from allopatric populations of the two pipistrelles and explored interspecific differences in time and frequency characteristics. We also conducted playback experiments by broadcasting recordings of social calls from P. kuhlii and P. maderensis (taken respectively in peninsular Italy and on Madeira) and monitoring the bats’ responses. Results Social call structure showed a strong similarity between species, whereas echolocation calls were markedly different and exhibited a mean divergence of over 6 kHz in their frequency of maximum energy. On Madeira, P. maderensis significantly reduced flight activity when we broadcast P. kuhlii signals, as did P. kuhlii in Italy in response to P. maderensis calls. Main conclusions Reliable interpretation of social calls provides benefits to both the signaller and the receiver because signals help to optimize food exploitation at foraging sites. In the absence of closely related species that can emit similar calls, this advantage may have acted as a strong evolutionary pressure, stabilizing social call structure in P. maderensis in insular ecosystems with limited foraging resources.

Helminth Component Community of the Loggerhead Sea Turtle, Caretta caretta, From Madeira Archipelago, Portugal

Abstract: The helminth fauna of pelagic-stage loggerhead sea turtles, Caretta caretta, is still poorly known. Here, we describe the helminth-component community of healthy, free-ranging juvenile loggerhead sea turtles captured in the waters around Madeira Island, Portugal. Fifty-seven were used in this study. The esophagus, stomach, intestine, liver, gallbladder, spleen, kidneys, trachea, bronchi, urinary bladder, heart, left and right aortas, and coelomic cavity were macroscopically inspected; organs and tissues were removed and washed through a sieve. A search for parasites was made using a stereoscopic microscope; recovered parasites were fixed and stored in 70% alcohol until staining and identification. Prevalence, mean intensity, and mean abundance values were recorded. In total, 156 parasite specimens belonging to 9 species were found: nematodes included Anisakis simplex s.l. (larvae) and an unidentified species; digenetic trematodes present were Enodiotrema megachondrus, Rhytidodes gelatinosus, Pyelosomum renicapite, and Calycodes anthos; acanthocephalans included Bolbosoma vasculosum and Rhadinorhynchus pristis; a single cestode, Nybelinia sp., was present. Parasite infections were found to have both low prevalences and intensities. Possible reasons for this include the oligotrophic conditions of the pelagic habitat around Madeira; a 'dilution effect' because of the vastness of the area; and the small size, and thus ingestion rate, of the turtles. Results are discussed in terms of the various turtle populations that may use the waters surrounding Madeira. This work provides valuable information on the parasite fauna of a poorly known stage in the life of loggerhead sea turtles, thereby filling a fundamental gap with regard to features of the parasite fauna in this species.

Investigating individual satisfaction in health and fitness training centres

Abstract: This paper analyses individual satisfaction in Health and Fitness Centres (HFCs) on the main Portuguese island of Madeira, based on a questionnaire survey conducted in 2007. A regression-ordered probit model is used to analyse preference determinants. The conclusion is that almost all of the attributes measured contribute to satisfaction, signifying that this is an area in which customers have high a priori expectations that are easily fulfilled. The policy implications are derived.