Rapid colour changes in multilayer reflecting stripes in the paradise whiptail, Pentapodus paradiseus

The Paradise whiptail (Pentapodus paradiseus) has distinct reflective stripes on its head and body. The reflective stripes contain a dense layer of physiologically active iridophores, which act as multilayer reflectors. The wavelengths reflected by these stripes can change from blue to red in 0.25 s. Transmission electron microscopy revealed that the iridophore cells contain plates that are, on average, 51.4 nm thick. This thickness produces a stack, which acts as an ideal quarter-wavelength multilayer reflector (equal optical thickness of plates and spaces) in the blue, but not the red, region of the spectrum. When skin preparations were placed into hyposmotic physiological saline, the peak wavelength of the reflected light shifted towards the longer (red) end of the visible spectrum. Hyperosmotic saline reversed this effect and shifted the peak wavelength towards shorter (blue/UV) wavelengths. Norepinephrine (100 mumol l(-1)) shifted the peak wavelength towards the longer end of the spectrum, while adenosine (100 mumol l(-1)) reversed the effects of norepinephrine. The results from this study show that the wavelength changes are elicited by a change of similar to70 nm in the distance between adjacent plates in the iridophore cells.

A rapid method for determining recent sunscreen use in field studies

The role of sunscreens in preventing skin cancer and melanoma is the focus of ongoing research. Currently, there is no objective measure which can be used in field studies to determine whether a person has applied sunscreen to their skin, and researchers must use indirect assessments such as questionnaires. We sought to develop a rapid, non-invasive method for identifying sunscreen on the skin for use in epidemiological studies. Our basic method is to swab the skin, elute any residues which have been adsorbed onto the swab by rinsing in ethanol, and submit the eluted washings for spectrophotometric analysis. In a controlled study, we applied 0.1 ml of sunscreen to a 50 cm(2) grid on both forearms of 21 volunteers. Each forearm was allocated one of 10 different sunscreen brands. The skin was swabbed after intervals of 20 min, 1 h, 2 h and 4 h. In a field study conducted among 12 children aged 2-4 years attending a child care centre, sunscreen was applied to the faces of half the children. Swabs were then taken from the face and back of all children without knowledge of sunscreen status. In the controlled study, sunscreen was clearly detectable up to 2 h after application for all brands containing organic sunscreen, and marginally detectable at 4 h. In the field study, this method correctly identified all children with and without sunscreen. We conclude that spectrophotometric analysis of skin swabs can reliably detect the presence of sunscreen on the skin for up to 2 It after application. (C) 2002 Elsevier Science B.V. All rights reserved.

Simultaneous observations of ionospheric quasiperiodic scintillations from short and long meridional baselines using VHF transmissions from transit satellites

For the first time it was possible to observe regular quasiperiodic scintillations (QPS) in VHF radio-satellite transmissions from orbiting satellites simultaneously at short (2.1 km) and long (121 km) meridional baselines in the vicinity of a typical mid-latitude station (Brisbane; 27.5degreesS and 152.9degreesE geog. and 35.6degrees invar.lat.), using three sites (St. Lucia-S, Taringa-T in Brisbane and Boreen Pt.-B, north of Brisbane). A few pronounced quasiperiodic (QP) events were recorded showing unambiguous regular structures at the sites which made it possible to deduce a time displacement of the regular fading minimum at S, T and B. The QP structure is highly dependent on the geometry of the ray-path from a satellite to the observer which is manifested as a change of a QP event from symmetrical to non-symmetrical for stations separated by 2.1 km, and to a radical change in the structure of the event over a distance of 121 km. It is suggested the short-duration intense QP events are due to a Fresnel diffraction (or a reflection mechanism) of radio-satellite signals by a single ionospheric irregularity in a form of an ellipsoid with a large ionization gradient along the major axis. The structure of a QP event depends on the angle of viewing of the irregular blob from a radio-satellite. In view of this it is suggested that the reported variety of the ionization formation, responsible for different types of QPS, is only apparent but not real. (C) 2003 Elsevier Science Ltd. All rights reserved.

Moravia : das lógicas da informalidade às lógicas da formalidade

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Arquitetura e Urbanismo, Programa de Pós-Graduação em Arquitetura e Urbanismo, 2016.

REENGINEERING THE CONCEPT OF URBAN CARS: A CASE STUDY

Based on a previously developed mathematical model for fuel consumption of a modular car, here we discuss the cross impacts of engineering scenarios vs. flexibility in use for modular vehicle architectures to achieve the reduction of CO2 emissions targeted by the European Union, in 2009. A systems perspective is adopted in conceptualizing a modular architecture of vehicles. From a theoretical viewpoint, we found modular architecture of vehicles a potential design strategy to minimize fuel inefficiencies and, thus, a strategy for design for environment.

The effects of place of residence on tourist motivations: a revised case of the Urban Quadrangle of Minho

This study seeks to capture the underlying reasons for the travel decisions of residents of the Urban Quadrangle of Minho (composed of the municipalities of Barcelos, Braga, Guimarães, and Vila Nova de Famalicão). The aim of the research is three-fold. Firstly, the study identifies the push and pull motivational factors of residents of the Urban Quadrangle of Minho. Secondly, the study examines whether there are differences between the tourist motivations of residents of the four different municipalities of the Urban Quadrangle. Finally, the study investigates if there are any differences in the motivations of those who choose national and international destinations. The methodology comprises quantitative research based on questionnaires administered in 2012 to residents of the Urban Quadrangle of Minho. A principal component factor analysis is employed to identify six push and seven pull factors. The comparison of the mean scores of these factors across municipalities and across residents that choose national and international destinations reveals that the most valued and least valued factors are common to all four municipalities and both groups of residents (that choose national and international destinations).

The effects of place of residence on tourist motivations: the case of Urban Quadrangle of Minho

The aim of this preliminary study is three-fold. Firstly, the study identifies the push and pull motivational factors of residents of the Urban Quadrangle of Minho. Secondly, the study examines whether there are differences between the tourist motivations of residents of the four different municipalities. Finally, the study investigates if there are any differences in the motivations of those who choose national and international destinations.

Tourist motivation of the residents of the Urban Quadrilátero of Minho: a gender analysis

Women are increasingly active in the participation and consumption of tourism, representing a strong and unique market segment. Knowledge of the needs and preferences of female tourists represents a key success factor in the tourism industry. This preliminary study seeks to capture the underlying reasons for the travel decisions of the residents of the Urban Quadrilátero of Minho, investigating their tourist motivations from a gendered perspective. Insight on tourism motivation may be an important policy tool for tourism planners and managers in the development of products and marketing strategies. The empirical analysis is undertaken based on questionnaires administered in 2012 to residents of the Urban Quadrilátero of Minho. Preliminary results do not reveal significant gender differences in the importance that the local residents place on various tourism motivation factors.

A creative solution for rapid and inexpensive model-making in product design processes

Innovative Developments in Virtual and Physical Prototyping

A creative solution for rapid and inexpensive model-making in product design processes

Rapid prototyping (RP) is an approach for automatically building a physical object through solid freeform fabrication. Nowadays, RP has become a vital aspect of most product development processes, due to the significant competitive advantages it offers compared to traditional manual model making. Even in academic environments, it is important to be able to quickly create accurate physical representations of concept solutions. Some of these can be used for simple visual validation, while others can be employed for ergonomic assessment by potential users or even for physical testing. However, the cost of traditional RP methods prevents their use in most academic environments on a regular basis, and even for very preliminary prototypes in many small companies. That results in delaying the first physical prototypes to later stages, or creating very rough mock-ups which are not as useful as they could be. In this paper we propose an approach for rapid and inexpensive model-making, which was developed in an academic context, and which can be employed for a variety of objects.