2,941 research outputs found
Microstrip resonator for microwaves with controllable polarization
In this work the authors implemented a resonator based upon microstrip
cavities that permits the generation of microwaves with arbitrary polarization.
Design, simulation, and implementation of the resonators were performed using
standard printed circuit boards. The electric field distribution was mapped
using a scanning probe cavity perturbation technique. Electron spin resonance
using a standard marker was carried out in order to verify the polarization
control from linear to circular.Comment: 3 pages, 3 figures, submitted to Appl. Phys. Let
Potential release of macronutrients and C sequestration of different land use systems in the Peruvian Amazon
Pregnancy, delivery and post-partum experiences: similarities and differences in portuguese mothers: from a TransCultural Study of Postnatal Depression (TCS-PND)
We aim to address the main similarities and differences in
pregnancy, delivery and postnatal experiences of Portuguese
mothers. In order to accomplish this purpose, 8 focus groups were
composed, each one with 4 to 6 participants. The sample, with a
total of 35 subjects, is quite heterogeneous regarding several social
and demographic characteristics. However, the majority of the
mothers had their first (45.7%) or the second child (45.7%), about
six months prior to the study.
The focus groups were held in Medical Centres and the
mothers were invited to participate by the nurses responsible for
the vaccination in those centres. Most mothers agreed to participate.
Those sessions occurred in the presence of two researchers
and were audio-taped. Some questions were presented for
discussion in the group, in order to focus the participants in their
pregnancy and postnatal experiences. Mothers contributions were
then transcribed and categorised using the IN-VIVO program.
The categorisation of themes resulting from mothers participation,
as well as some examples of their contributions, which had been
categorised in each one of the themes, are presented.
Similarities and differences found in pregnancy, delivery and
postnatal experiences in this Portuguese sample, along with the
advantages of using a qualitative methodology when conducting
a study with this kind of purpose, are discussed. In relation to
observations in others countries, results show the great
importance of the quality of the relationship and support from
extended family and husband to the happiness of Portuguese
women during pregnancy and postpartum; nevertheless the
mothers complain of the intrusiveness of the family after delivery.
Also, as far as postnatal depression is concerned, and regarding to
the causes, almost all the mothers conveyed that overwork and
lack of support from husband and from mother might lead to
depression after delivery
Perspectives on engineering more usable context-aware systems
The expectations of the abilities of context-aware systems (C-AS) often differ from reality. It becomes difficult to program contextual services that react adequately to the circumstantial needs of users as developers need to know, beforehand: the set of contextual states that may exist, what information could accurately determine a contextual state within that set, and what appropriate action should be taken in that particular state. Although there exist many frameworks and tools which support the design and implementation of C-AS, there is less conceptual help for developers to inform them of what contextual situations and services are appropriate (or feasible) to be implemented. This report reviews the state-of-the-art conceptualisation of context, which is more focused on the representational interpretation of the concept, to introduce a perspective that also acknowledges its interactional interpretation. A combination of revised and new definitions is introduced, which give key insights for the development of more useful C-AS. By acknowledging situations as a dynamic phenomenon that arises from action (interaction), and needs to be understood by the developers, it facilitates the analysis of these subjective interpretations into programming constructs (representation). The conceptualisation is also complemented with a set of guidelines for developers, an illustration of their usage, and a further discussion on the future directions for the engineering of more usable C-AS. The introduced conceptualisation is targeted towards the creation of an open-source tool supported framework for the engineering of C-AS
The 12 prophets dataset
The "Ajeijadinho 3D" project is an initiative supported by the University of
S\~ao Paulo (Museum of Science and Dean of Culture and Extension), which
involves the 3D digitization of art works of Brazilian sculptor Antonio
Francisco Lisboa, better known as Aleijadinho. The project made use of advanced
acquisition and processing of 3D meshes for preservation and dissemination of
the cultural heritage. The dissemination occurs through a Web portal, so that
the population has the opportunity to meet the art works in detail using 3D
visualization and interaction. The portal address is
http://www.aleijadinho3d.icmc.usp.br. The 3D acquisitions were conducted over a
week at the end of July 2013 in the cities of Ouro Preto, MG, Brazil and
Congonhas do Campo, MG, Brazil. The scanning was done with a special equipment
supplied by company Leica Geosystems, which allowed the work to take place at
distances between 10 and 30 meters, defining a non-invasive procedure,
simplified logistics, and without the need for preparation or isolation of the
sites. In Ouro Preto, we digitized the churches of Francisco of Assis, Our Lady
of Carmo, and Our Lady of Mercy; in Congonhas do Campo we scanned the entire
Sanctuary of Bom Jesus de Matosinhos and his 12 prophets. Once scanned, the art
works went through a long process of preparation, which required careful
handling of meshes done by experts from the University of S\~ao Paulo in
partnership with company Imprimate.Comment: Full dataset online at http://aleijadinho3d.icmc.usp.br/data.htm
Construction of Chemoenzymatic Linear Cascades for the Synthesis of Chiral Compounds
Inspired by nature, synthetic chemists try to mimic the efficient metabolic networks in living organisms to build complex molecules by combining different types of catalysts in the same reaction vessel. These multistep cascade processes provide many advantages to synthetic procedures, resulting in higher productivities with lower waste generation and cost. However, combining different chemo- and biocatalysts can be challenging as reaction conditions might differ greatly. As a highly multidisciplinary field that benefits from advances in chemical catalysis, molecular biology and reaction engineering, this area of study is rapidly progressing. In this Review, we highlight recent trends and advances in the construction of multistep chemoenzymatic one-pot cascades to access chiral compounds as well as the different strategies to solve current challenges in the field
Lande g-tensor in semiconductor nanostructures
Understanding the electronic structure of semiconductor nanostructures is not
complete without a detailed description of their corresponding spin-related
properties. Here we explore the response of the shell structure of InAs
self-assembled quantum dots to magnetic fields oriented in several directions,
allowing the mapping of the g-tensor modulus for the s and p shells. We found
that the g-tensors for the s and p shells show a very different behavior. The
s-state in being more localized allows the probing of the confining potential
details by sweeping the magnetic field orientation from the growth direction
towards the in-plane direction. As for the p-state, we found that the g-tensor
modulus is closer to that of the surrounding GaAs, consistent with a larger
delocalization. These results reveal further details of the confining
potentials of self-assembled quantum dots that have not yet been probed, in
addition to the assessment of the g-tensor, which is of fundamental importance
for the implementation of spin related applications.Comment: 4 pages, 4 figure
Real-Time fusion of visual images and laser data images for safe navigation in outdoor environments
[EN]In recent years, two dimensional laser range finders mounted on vehicles is becoming a
fruitful solution to achieve safety and environment recognition requirements (Keicher &
Seufert, 2000), (Stentz et al., 2002), (DARPA, 2007). They provide real-time accurate range
measurements in large angular fields at a fixed height above the ground plane, and enable
robots and vehicles to perform more confidently a variety of tasks by fusing images from
visual cameras with range data (Baltzakis et al., 2003). Lasers have normally been used in
industrial surveillance applications to detect unexpected objects and persons in indoor
environments. In the last decade, laser range finder are moving from indoor to outdoor rural
and urban applications for 3D imaging (Yokota et al., 2004), vehicle guidance (Barawid et
al., 2007), autonomous navigation (Garcia-Pérez et al., 2008), and objects recognition and
classification (Lee & Ehsani, 2008), (Edan & Kondo, 2009), (Katz et al., 2010). Unlike
industrial applications, which deal with simple, repetitive and well-defined objects, cameralaser
systems on board off-road vehicles require advanced real-time techniques and
algorithms to deal with dynamic unexpected objects. Natural environments are complex
and loosely structured with great differences among consecutive scenes and scenarios.
Vision systems still present severe drawbacks, caused by lighting variability that depends
on unpredictable weather conditions. Camera-laser objects feature fusion and classification
is still a challenge within the paradigm of artificial perception and mobile robotics in
outdoor environments with the presence of dust, dirty, rain, and extreme temperature and
humidity. Real time relevant objects perception, task driven, is a main issue for subsequent
actions decision in safe unmanned navigation. In comparison with industrial automation
systems, the precision required in objects location is usually low, as it is the speed of most
rural vehicles that operate in bounded and low structured outdoor environments.
To this aim, current work is focused on the development of algorithms and strategies for
fusing 2D laser data and visual images, to accomplish real-time detection and classification
of unexpected objects close to the vehicle, to guarantee safe navigation. Next, class
information can be integrated within the global navigation architecture, in control modules,
such as, stop, obstacle avoidance, tracking or mapping.Section 2 includes a description of the commercial vehicle, robot-tractor DEDALO and the
vision systems on board. Section 3 addresses some drawbacks in outdoor perception.
Section 4 analyses the proposed laser data and visual images fusion method, focused in the
reduction of the visual image area to the region of interest wherein objects are detected by
the laser. Two methods of segmentation are described in Section 5, to extract the shorter area
of the visual image (ROI) resulting from the fusion process. Section 6 displays the colour
based classification results of the largest segmented object in the region of interest. Some
conclusions are outlined in Section 7, and acknowledgements and references are displayed
in Section 8 and Section 9.projects: CICYT- DPI-2006-14497 by the Science
and Innovation Ministry, ROBOCITY2030 I y II: Service Robots-PRICIT-CAM-P-DPI-000176-
0505, and SEGVAUTO: Vehicle Safety-PRICIT-CAM-S2009-DPI-1509 by Madrid State
Government.Peer reviewe
Problema de contratación de carretilleros para un almacén de productos manufacturados
En este trabajo se analiza un problema planteado recientemente a sus autores por una empresa fabricante de componentes de automóviles. Dicha empresa almacena sus productos manufacturados hasta que los clientes (compradores) pasan a recogerlos. Los clientes solicitan sus productos con una frecuencia conocida. Se trata de determinar, en función de dichas frecuencias, en qué fechas y a qué horas o slots han de pasar los clientes a recoger sus pedidos. Fijado el horizonte temporal objeto de estudio, el objetivo para la empresa es minimizar en ese conjunto de dÃas, el número de carretilleros necesarios para cargar los pedidos en los camiones de los clientes. El número de carretilleros diarios viene determinado por el slot más ocupado. En este problema se han de tomar decisiones a dos niveles: elaboración del calendario de entrega para cada uno de los pedidos, y asignación diaria de pedidos a slots. No se ha encontrado en la literatura ningún trabajo que estudie o pueda ajustarse a este problema. Se diseñan y analizan 3 sencillos MetaheurÃsticos: uno sigue un proceso de Búsqueda Tabú básico, otro es un procedimiento de Búsqueda en Entorno Variable y el tercero es un Algoritmo Evolutivo. Se realizan pruebas con instancias ficticias y por último se resulven las instancias reales planteadas a los autores de este trabajo
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