992 resultados para Methodological importance


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Portuguese National Statistical Institute intends to produce estimations for the mean price of the habitation transation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In recent decades, the combination of tourism and Information and Communication Technologies (ICT), has originated considerable changes in tourists’ behaviour. The analysis of tourism demand resulting from the Internet is of growing importance, given the increasing number of online reservations observed in recent years. However, in order to analyse the new trends caused by online bookings, the availability of data enabling the measurement and characterization of this phenomenon is essential. This has, however, been a considerable limitation, given that either no data on key variables is available or the available data is sometimes of questionable quality. For professionals and researchers in the area of tourism, the high volume of tourists who use the Internet to make hotel and travel reservations is worth of consideration, given that it may potentiate the discovery of new source markets, the identification of clients with different characteristics and may help explain the dynamics between suppliers or countries. The existence of predictive studies to support decision-making and planning, by professionals of the tourism sector, is of great importance. Panel data models are a useful and appropriate method for the analysis and modelling of tourism demand. These models consider both the time series and the cross-sectional dimensions of the data and allow for the inclusion of social variables. The results of estimation of tourism demand, through panel data models, show that the Internet and the sharp technological development have encouraged the increasing demand for tourism. The growing number of tourism companies online will naturally promote or potentiate an increase of tourism demand.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The undesirable enrichment of water by nutrients may be a problem, especially in areas with restricted exchange with the sea. The tidal regime flushes the system and contributes for the removal of phytoplankton, favouring phytobenthos as the target of enhanced nutrients. Water samples were collected during the years of 2006 and 2007-08 for nutrients, chlorophyll a and dissolved oxygen. Sediment sample s were also collected for pore water nutrients and benthic chlorophyll a. From comparison with previous work, a decrease in the nitrogen concentration in the water column can be pointed out, which may indicate an improvement of the water quality. Pore water DAIN represents approximately 75% of the total DAIN of the whole lagoon. Benthic chlorophyll a concentrations were much larger than in the water column, representing around 99% of the total chlorophyll existent in the lagoon. Benthic microalgae play a relevant role in this system and therefore standard monitoring programs of the WFD, which do not consider this component, may fail to track nutrient-driven changes in primary producers. Dissolved oxygen concentration could be near critical levels during the summer (early in the morning), especially in the inner channels.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Despite the importance of larval abundance in determining the recruitment of benthic marine invertebrates and as a major factor in marine benthic community structure, relating planktonic larval abundance with post-settlement post-larvae and juveniles in the benthos is difficult. It is hampered by several methodological difficulties, including sampling frequency, ability to follow larval and post-larval or juvenile cohorts, and ability to calculate growth and mortality rates. In our work, an intensive sampling strategy was used. Larvae in the plankton were collected at weekly intervals, while post-larvae that settled into collectors were analysed fortnightly. Planktonic larval and benthic post-larval/juvenile cohorts were determined, and growth and mortality rates calculated. Integration of all equations allowed the development of a theoretical formulation that, based on the abundance and planktonic larval duration, permits an estimation of the future abundance of post-larvae/juveniles during the first year of benthic life. The model can be applied to a sample in which it was necessary only to measure larval length.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The wedge shell, Donax trunculus, inhabits high energy environment of exposed sandy beaches from the Atlantic coast of France to Senegal. Like all Donacidae, it is relative small, flat-shaped with elongated solid shells. It is a highly demanded and valuable species mainly in Algarve, with the dredge fleet increasing the pressure on species stocks. In 1986 the Portuguese Institute for the Ocean and Atmosphere (IPMA) initiated a bivalve survey program to evaluate the stock status of species with economical valuable but always on the adult population. Since then, several managing measures were implemented to guarantee bivalves’ sustainable exploitation. Despite the available information on the abundance and distribution of the wedge shell along the Algarve coast, no information on the larval planktonic phase is available. To fill in this gap, the present study aimed at obtaining, for the first time information on the broodstock condition and on the pelagic phase of the wedge shell in the Algarve coast.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this work we develop a methodology for the economic evaluation of soil tillage technologies, in a risky environment, and to capture the influence of farmer behaviour on his technology choice. The model has short-term activities, that change with the type of year, and long-term activities, in which sets of traction investment activities are included. Although these activities do not change with the type of year, they lead to different availability of resources for each type of year, since the same tractor has different available fieldwork days under different weather conditions. We prove that the model is sensitive to the greater income variability resulting from the use of alternative technologies and to the balance between income and risk, accounting for the probability of occurrence of each state of nature and giving an investment solution that considers the best production plan for each type of year. (c) 2005 Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tese de mestrado, Educação (Didáctica das Ciências), Universidade de Lisboa, Instituto de Educação, 2010

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tese de doutoramento, Ciências Biomédicas (Neurociências), Universidade de Lisboa, Faculdade de Medicina, 2014

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Daily average Alnus pollen counts (1996-2005) from Worcester (UK) and Poznań (Poland) were examined with the aim of assessing the regional importance of Alnus pollen as an aeroallergen. The average number of Alnus pollen grains recorded annually at Poznań was more than 2.5 times that of Worcester. Furthermore, daily average Alnus pollen counts exceeded the thresholds of 100, 500 and 1,000 grains/m3 more times at Poznań than Worcester. Skin prick test results (1996-2005) and allergen-specific IgE(asIgE) measurements using the CAP (Pharmacia) system (2002-2005), were supplied by the Allergic Diseases Diagnostic Centre in Poznań. The annual number of positive skin prick tests to Alnus pollen allergens was significantly related (p<0.05) to seasonal variations in the magnitude of the Alnus pollen catch recorded at Poznań (r=0.70). The symptoms of patients with positive skin prick tests to Alnus pollen allergens were: 51% pollinosis, 43% atopic dermatitis, 4% asthma, 1% chronic urticaria and 1% eczema. On a scale of 0-6, 20.5% of patients examined for serum asIgE in relation to Alnus pollen allergens had asIgE measurements in classes 5 and 6. Alnus pollen is generally considered to be mildly allergenic. However, the amount of Alnus pollen released into the atmosphere in places such as Poznań may increase its impact on the population and make it one of the more important aeroallergens present.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tese de doutoramento, Biologia (Biologia da Conservação), Universidade de Lisboa, Faculdade de Ciências, 2015

Relevância:

20.00% 20.00%

Publicador:

Resumo:

VITAE was a four-year research project designed to explore the work and lives of a purposive sample of 300 Key Stage 1, 2 and 3 (English and maths) teachers at different phases of their careers in 100 primary and secondary schools in different socioeconomic contexts, drawn from seven local authorities in England. Its focus was upon identifying variations in different aspects of teachers' lives and work and examining possible connections between these and their effects on pupils as perceived by the teachers themselves and as measured by value-added national test scores. An integrated mixed-method approach was developed in addressing the research questions. The results showed that there were associations between teachers' work, lives and identities, that teachers' perceived and relative (valueadded) effectiveness varied within each of six professional life phases, and that this variation depended upon their capacity to manage a number of moderating and mediating factors. Statistically significant relationships were found between teacher commitment, resilience and the value-added pupil test scores. The findings from the study shed new light upon the meanings and measurement of teacher effectiveness and the complex nature and trajectories of teachers' work, lives and effectiveness in different school contexts.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tese de doutoramento, Biologia (Biologia Marinha e Aquacultura), Universidade de Lisboa, Faculdade de Ciências, 2015

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tese de doutoramento, História e Filosofia das Ciências, Universidade de Lisboa, Faculdade de Ciências, 2015

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Senior thesis written for Oceanography 444