999 resultados para Ecological compensation


Relevância:

20.00% 20.00%

Publicador:

Resumo:

First described more that 150 years ago, the systematics of the genera Geomalacus and Letourneuxia (Arionidae, Gastropoda, Pulmonata) is still challenging. The taxonomic classification of arionid species is based on extremely labile characters such as body size or color that depends both on diet and environment, as well as age. Moreover, there is little information on the genetic diversity and population structure of the Iberian slugs that could provide extra clues to disentangle their problematic classification. The present work uses different analytical tools such as habitat suitability (Ecological Niche Modeling - ENM), cytogenetic analysis and phylogeography to establish the geographical distribution and evolutionary history of these pulmonate slugs. The potential distribution of the four Geomalacus species was modeled using ENM, which allowed the identification of new locations for G. malagensis, including a first report in Portugal. Also, it was predicted a much wider distribution for G. malagensis and G. oliveirae than previously known. Classical cytogenetic analyses were assayed with reproductive and a novel use of somatic tissues (mouth and tentacles) returning the number of chromosomes for the four Geomalacus species and L. numidica (n = 31, 2n = 62) and the respective karyotypes. G. malagensis and L. numidica present similar chromosome morphologies and karyotypic formulae, being more similar to each other than the Geomalacus among themselves. We further reconstructed the phylogeny of the genera Geomalacus and Letourneuxia using partial sequences of the mitochondrial cytochrome oxidase subunit I (COI) and the nuclear ribosomal small subunit (18S rRNA), and applied an independent evolutionary rate method, the indicator vectors correlation, to evaluate the existence of cryptic diversity within species. The five nominal species of Geomalacus and Letourneuxia comprise 14 well-supported cryptic lineages. Letourneuxia numidica was retrieved as a sister group of G. malagensis. G. oliveirae is paraphyletic with respect to G. anguiformis. According to our dating estimates, the most recent common ancestor of Geomalacus dates back to the Middle Miocene (end of the Serravallian stage). The major lineage splitting events within Geomalacus occurred during the dry periods of the Zanclean stage (5.3-3.6 million years) and some lineages were confined to more humid mountain areas of the Iberian Peninsula, which lead to a highly geographically structured mitochondrial genetic diversity. The major findings of this are the following: (1) provides updated species distribution maps for the Iberian Geomalacus expanding the known geographic distribution of the concerned species, (2) unravels the cryptic diversity within the genera Geomalacus and Letourneuxia, (3) Geomalacus oliveirae is paraphyletic with G. anguiformis and (4) Letourneuxia numidica is sister group of G. malagensis.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tese de doutoramento, Biologia (Biologia Evolutiva), Universidade de Lisboa, Faculdade de Ciências, 2014

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This work addresses the joint compensation of IQimbalances and carrier phase synchronization errors of zero- IF receivers. The compensation scheme based on blind-source separation which provides simple yet potent means to jointly compensate for these errors independent of modulation format and constellation size used. The low-complexity of the algorithm makes it a suitable option for real-time deployment as well as practical for integration into monolithic receiver designs.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

I and Q Channel phase and gain misniatches are of great concern in communications receiver design. In this paper we analyse the effects of I and Q channel mismatches and propose a low-complexity blind adaptive algorithm to minimize this problem. The proposed solution consists of two, 2-tap adaptive filters, arranged in Adaptive Noise Canceller (ANC) set-up, with the output of one cross-fed to the input of the other. The system works as a de-correlator eliminating I and Q mismatch errors.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Wetland socio-ecological systems provide livelihood benefits for many poor people throughout the developing world, yet their sustainable development requires local utilisation strategies that balance both environmental and development outcomes. Community-based local institutional arrangements that mediate peoples’ relationships with their environment and facilitate adaptive co-management offer one means of achieving this, and increasingly many NGOs and development practitioners have sought to integrate local institutional capacity-building into development projects. In the context of wider academic debates surrounding the long-term sustainability of externally-facilitated local institutions, this paper draws on the experiences of the three-year Striking a Balance (SAB) project in Malawi which sought to embed sustainable wetland management practices within community-based local institutional arrangements. Drawing on field data collected through participatory methods at three project sites some five years after the cessation of project activities, we examine the extent to which SAB’s local institutional capacity-building has been successful, and from this draw some lessons for externally-driven project interventions which seek win-win outcomes for people and the environment. With reference to Elinor Ostrom’s design principles for long-enduring common property resource institutions, we suggest that the observed declining effectiveness of SAB’s local institutions can be attributed to issues of stakeholder inclusiveness and representations; their sustainability was arguably compromised from their inception on account of them being nested within pre-existing, externally-driven village ‘clubs’ whose membership and decision-making was not congruent with all the wetland stakeholders within the community.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Global navigation satellite system (GNSS) receivers require solutions that are compact, cheap and low-power, in order to enable their widespread proliferation into consumer products. Furthermore, interoperability of GNSS with non-navigation systems, especially communication systems will gain importance in providing the value added services in a variety of sectors, providing seamless quality of service for users. An important step into the market for Galileo is the timely availability of these hybrid multi-mode terminals for consumer applications. However, receiver architectures that are amenable to high-levels of integration will inevitably suffer from RF impairments hindering their easy widespread use in commercial products. This paper studies and presents analytical evaluations of the performance degradation due to the RF impairments and develops algorithms that can compensate for them in the DSP domain at the base band with complexity-reduced hardware overheads, hence, paving the way for low-power, highly integrated multi-mode GNSS receivers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper presents compensation of all undesired effects (Power Amplifier (PA) nonlinearity, transmitter and receiver antenna crosstalk, before-PA nonlinear crosstalk, Multiple Input Multiple Output (MIMO) channel fading and crosstalk) in MIMO Orthogonal Frequency Division Multiplex (OFDM) wireless systems. It has been demonstrated that reduced-complexity Crossover Digital Predistortion (CO-DPD) algorithm on transmitter side and Matrix Inversion algorithm on receiver side can suppress almost all undesired effects introduced by transmitter, channel and receiver in 4×4 MIMO OFDM System that can be used in modern wireless system applications. A significant complexity reduction is achieved due to the fact that Digital Signal Processing (DSP) during CO-DPD process on transmitter side is done with real instead of complex numbers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This article reconsiders the House of Lords decision in Rees v. Darlington Memorial Hospital NHS Trust (2003) and the decision to award a conventional award of £15,000 in all cases of failed sterilisation resulting in the birth of an unwanted child. In so doing, it briefly recites the history of the Wrongful Conception action and the unique facts of Rees. It then goes on the consider the implications of two fundamental aspects of the judgment. Firstly, it looks at the 'conventional award' itself and considers the reasoning behind the award and the effect that it has on our understanding of (particularly women's) reproductive autonomy. Secondly, it analyses the rather 'unique' judgment of Lord Scott and his decision to evaluate these cases using the possessory analogy of an unwanted foal; particular focus is given to the notion of parental 'choice' in these cases and whether mitigation (i.e. abortion or adoption) can ever be considered "reasonable".

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Thesis (Ph.D.)--University of Washington, 2016-03

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Technocratic attitudes suggest that decisions about environmental policy should be led by scientific experts. Such decisions, it is expected, will be more rational than any arrived at by a democratic mediation between the narrow, short-term interests and uninformed preferences of the general public. Within green political theory, deliberative democracy has emerged as the dominant repost to technocracy, offering an account of how democratic polities can deal with complex scientific and technological decisions through the emergence of communicative rationality. This article argues that neither appeals to expert knowledge, nor communicative rationality, are likely to deliver the optimal green outcomes that proponents suggest, but rather will cover up the inevitable disagreements over environmental policy making. Instead the article suggests that more ecologically-sensitive and democratic decision making about complex scientific and technological issues can emerge if we acknowledge the differently embodied perspectives of decision-makers – from scientists to citizens. This prioritises democratic means over green ends, yet incorporates the environment at the beginning of the decision-making process. The article aims to sketch out the theoretical and practical implications of such an embodied turn for responding to the anti-democratic tendencies of environmental technocracy.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper presents a methodology to address reactive power compensation using Evolutionary Particle Swarm Optimization (EPSO) technique programmed in the MATLAB environment. The main objective is to find the best operation point minimizing power losses with reactive power compensation, subjected to all operational constraints, namely full AC power flow equations, active and reactive power generation constraints. The methodology has been tested with the IEEE 14 bus test system demonstrating the ability and effectiveness of the proposed approach to handle the reactive power compensation problem.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper presents a Unit Commitment model with reactive power compensation that has been solved by Genetic Algorithm (GA) optimization techniques. The GA has been developed a computational tools programmed/coded in MATLAB. The main objective is to find the best generations scheduling whose active power losses are minimal and the reactive power to be compensated, subjected to the power system technical constraints. Those are: full AC power flow equations, active and reactive power generation constraints. All constraints that have been represented in the objective function are weighted with a penalty factors. The IEEE 14-bus system has been used as test case to demonstrate the effectiveness of the proposed algorithm. Results and conclusions are dully drawn.