922 resultados para New ecological paradigm


Relevância:

30.00% 30.00%

Publicador:

Resumo:

This article develops an ecological economic interpretation of the Jevons effect. Moreover, it is argued that under the neoclassical paradigm there are no elements with which to foresee the long-term existence of this phenomenon. The objective of these arguments is to demonstrate that the Jevons effect can be used to compare the ability of neoclassical and ecological economics describing the social appropriation of nature. This is elaborated in two steps. First, we show the importance of the thesis that the economy cannot be cut off from the biophysical materiality of what is produced to give consistency to the so-called Khazzoom-Brookes postulate. It is made clear that this supposition is exogenous to the neoclassical paradigm. Second, the supposition of the biophysical materiality of what is produced is utilized to make an ecological economic interpretation of the Jevons effect. Afterwards, a comparison is made between the neoclassical and the ecological economic perspectives. This comparison leads to the following conclusions: (i) the persistent presence of the Jevons effect in the long run is an anomaly in the neoclassical paradigm; (ii) the observation of the non-existence of the Jevons effect is a refutation of the supposition that economic growth and biophysical materiality are not separable, a central thesis defended by ecological economists. This situation makes possible to use the Jevons effect as a 'laboratory test' to compare the ability of neoclassical and ecological economic paradigms to describe the social appropriation of nature. (C) 20111 Elsevier B.V. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The Brachiopoda of the Marine Protected Area “Secche di Tor Paterno”, Central Tyrrhenian Sea, have been investigated in order to give a first glance of the diversity of the brachiopods of this area and provide a new report on the Mediterranean Brachiopod fauna. Four species were reported: Novocrania anomala (Müller, 1776), Megathiris detruncata (Gmelin, 1790), Joania cordata (Risso,1826) and Argyrotheca cuneata (Risso,1826). For all the four species a morphological analysis was carried out. For the two most abundant species, J.cordata and A. cuneata, a morphometric study, based on thickness/width and length/width scattergrams, was carried out, in order to investigate their variability. Size-frequency distributions relative to the three dimensions of the shell were also computed, aimed at a evaluation of population dynamics of these two species. The results showed that, for both species, the parameters which most determine the rise of the shell during the growth of animal are width and length and that frequency distributions are mainly bi- or plurymodal and that they are difficult to interpret, as reported by other studies. Analysis of drill holes found on the shell of some specimens of the two same species revealed a predatory origin and that three different predators are responsible for them. Partial sequences of two different genetic markers, the Internal Transcribed Spacer 1 (ITS1) and the cytochrome oxidase subunit 1 (COI), were used to investigate the phylogenetic relationship between two populations of the eurybathic brachiopod species Gryphus vitreus (Born,1778) across the strait of Gibraltar. This represents the first genetic population study on brachiopods. Results from AMOVA and Bayesian analysis performed on 31 specimens highlighted no genetic differentiation indicating a likely panmixia, dispite the lecitotrophic development of the species.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In the last decade, the reverse vaccinology approach shifted the paradigm of vaccine discovery from conventional culture-based methods to high-throughput genome-based approaches for the development of recombinant protein-based vaccines against pathogenic bacteria. Besides reaching its main goal of identifying new vaccine candidates, this new procedure produced also a huge amount of molecular knowledge related to them. In the present work, we explored this knowledge in a species-independent way and we performed a systematic in silico molecular analysis of more than 100 protective antigens, looking at their sequence similarity, domain composition and protein architecture in order to identify possible common molecular features. This meta-analysis revealed that, beside a low sequence similarity, most of the known bacterial protective antigens shared structural/functional Pfam domains as well as specific protein architectures. Based on this, we formulated the hypothesis that the occurrence of these molecular signatures can be predictive of possible protective properties of other proteins in different bacterial species. We tested this hypothesis in Streptococcus agalactiae and identified four new protective antigens. Moreover, in order to provide a second proof of the concept for our approach, we used Staphyloccus aureus as a second pathogen and identified five new protective antigens. This new knowledge-driven selection process, named MetaVaccinology, represents the first in silico vaccine discovery tool based on conserved and predictive molecular and structural features of bacterial protective antigens and not dependent upon the prediction of their sub-cellular localization.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The perspective of the present project can be inscribed in the so-called “Social Cognition” framework, that in the last years moved from a focus on the individual mind toward embodied and participatory aspects of social understanding. Among the topics relevant for social cognition, the aim of the thesis was to shed more light on motor resonance and joint action, by using two well-known effects of cognitive psychology: “Affordance” and “Simon”. In the first part of the project, the Affordance effect has been considered, starting from Gibson to some post-Gibsonian theorizations. Particular attention has received the notion of “Micro-affordance”. The theoretical and empirical overview allows to understand how it can be possible to use the affordance effect to investigate the issue of motor resonance. A first study employed a priming paradigm and explored both in adults and school-age children the influence of a micro-affordance that can be defined dangerousness, and how motor resonance develops. The second part of the thesis focused on the Simon effect, starting with the presentation of the “stimulus–response (S–R) compatibility effect” to introduce the “Simon effect”. Particular attention has been dedicated to recent studies on the “joint Simon effect”. The reviewed empirical findings have been discussed in a wider theoretical perspective on joint action. The second study was aimed at investigating whether shared representations, as indexed by the presence of the joint Simon effect, are modulated by minimal ingroup–outgroup distinctions and by experienced interdependence between participants. The third study explored to what extent prior experience could modulate performance in task sharing, combining two paradigms of cognitive psychology, the joint Simon and the joint transfer-of-learning. In a general discussion the results obtained in the three studies have been summarized, emphasizing their original contribution and their importance within the Social Cognition research.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Seizures are often the presenting symptoms of a cerebral tumor and may precede its diagnosis by many years. The article under evaluation searched two large English registries for patients admitted for new-onset epilepsy. The risk of subsequently being diagnosed with a malignant brain tumor was found to be 26-fold higher compared with controls, persisted over many years and was accentuated in young patients. Recently, surgical advances have led to a significant decrease in surgical morbidities, making surgery the first treatment option for gliomas, especially low-grade gliomas. This paradigm shift warrants a consequent diagnostic workup (MRI) in patients at risk for low-grade glioma - that is, patients with new-onset epilepsy. The study is discussed in the context of the ongoing debate on neuroimaging after new-onset epilepsy.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

To date it remains unclear if a delayed surgical treatment of open hand injuries after more than 6 h may be detrimental to outcome. Previous investigations by McLain et al. (J Hand Surg Am 16:108-112, 1980 9), Nylen and Carlsson (Scand J Plast Reconstr Surg 14:185-189, 1991 10) could not find statistical proof of correlation between infection rate and delayed surgical treatment after open hand injuries up to 18 h. The current study was designed to investigate the outcome of early versus delayed surgical treatment after open hand injury.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Research on speciation and adaptive radiation has flourished during the past decades, yet factors underlying initiation of reproductive isolation often remain unknown. Parasites represent important selective agents and have received renewed attention in speciation research. We review the literature on parasite-mediated divergent selection in context of ecological speciation and present empirical evidence for three nonexclusive mechanisms by which parasites might facilitate speciation: reduced viability or fecundity of immigrants and hybrids, assortative mating as a pleiotropic by-product of host adaptation, and ecologically-based sexual selection. We emphasise the lack of research on speciation continuums, which is why no study has yet made a convincing case for parasite driven divergent evolution to initiate the emergence of reproductive isolation. We also point interest towards selection imposed by single vs. multiple parasite species, conceptually linking this to strength and multifariousness of selection. Moreover, we discuss how parasites, by manipulating behaviour or impairing sensory abilities of hosts, may change the form of selection that underlies speciation. We conclude that future studies should consider host populations at variable stages of the speciation process, and explore recurrent patterns of parasitism and resistance that could pinpoint the role of parasites in imposing the divergent selection that initiates ecological speciation.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The interface between climate and ecosystem structure and function is incompletely understood, partly because few ecological records start before the recent warming phase. Here, we analyse an exceptional 100-yr long record of the great tit (Parus major) population in Switzerland in relation to climate and habitat phenology. Using structural equation analysis, we demonstrate an uninterrupted cascade of significant influences of the large-scale atmospheric circulation (North-Atlantic Oscillation, NAO, and North-sea – Caspian Pattern, NCP) on habitat and breeding phenology, and further on fitness-relevant life history traits within great tit populations. We then apply the relationships of this analysis to reconstruct the circulation-driven component of fluctuations in great tit breeding phenology and productivity on the basis of new seasonal NAO and NCP indices back to 1500 AD. According to the structural equation model, the multi-decadal oscillation of the atmospheric circulation likely led to substantial variation in habitat phenology, productivity and consequently, tit population fluctuations with minima during the "Maunder Minimum" (∼ 1650–1720) and the Little Ice Age Type Event I (1810–1850). The warming since 1975 was not only related with a quick shift towards earlier breeding, but also with the highest productivity since 1500, and thus, the impact of the NAO and NCP has contributed to an unprecedented increase of the population. A verification of the structural equation model against two independent data series (1970–2000 and 1750–1900) corroborates that the retrospective model reliably depicts the major long-term NAO/NCP impact on ecosystem parameters. The results suggest a complex cascade of climate effects beginning at a global scale and ending at the level of individual life histories. This sheds light on how large-scale climate conditions substantially affect major life history parameters within a population, and thus influence key ecosystem parameters at the scale of centuries.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Many efforts have been made in Ethiopia to mitigate land degradation, particularly soil erosion, through both local and newly introduced soil and water conservation (SWC) practices. However, the strict focus on soil erosion and conservation does not necessarily lead to satisfactory results. If SWC is effective in reducing erosion but is at the same time too costly and unacceptable to land users, sooner or later it will disappear and its positive effects will also be lost. This book therefore suggests to follow the broader approach of Sustainable Land Management (SLM), which aims at ecological soundness, economic viability and social acceptability, and thus places SWC in a more holistic framework that is closer to farmers’ reality.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The sudden independence of Kyrgyzstan from the Soviet Union in 1991 led to a total rupture of industrial and agricultural production. Based on empirical data, this study seeks to identify key land use transformation processes since the late 1980s, their impact on people's livelihoods and the implication for natural resources in the communes of Tosh Bulak and Saz, located in the Sokuluk River Basin on the northern slope of the Kyrgyz Range. Using the concept of the sustainable livelihood approach as an analytical framework, three different livelihood strategies were identified: (1) An accumulation strategy applied by wealthy households where renting and/or buying of land is a key element; they are the only household category capable of venturing into rain fed agriculture. (2) A preserving strategy involving mainly intermediate households who are not able to buy or rent additional agricultural land; very often they are forced to return their land to the commune or sell it to wealthier households. (3) A coping strategy including mainly poor households consisting of elderly pensioners or headed by single mothers; due to their limited labour and economic power, agricultural production is very low and hardly covers subsistence needs; pensions and social allowances form the backbone of these livelihoods. Ecological assessments have shown that the forage productivity of remote high mountain pastures has increased from 5 to 22 per cent since 1978. At the same time forage productivity on pre-mountain and mountain pastures close to villages has generally decreased from 1 to 34 per cent. It seems that the main avenues for livelihoods to increase their wealth are to be found in the agricultural sector by controlling more and mainly irrigated land as well as by increasing livestock. The losers in this process are thus those households unable to keep or exploit their arable land or to benefit from new agricultural land. Ensuring access to land for the poor is therefore imperative in order to combat rural poverty and socio-economic disparities in rural Kyrgyzstan.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

A fundamental assumption in invasion biology is that most invasive species exhibit enhanced performance in their introduced range relative to their home ranges. This idea has given rise to numerous hypotheses explaining “invasion success” by virtue of altered ecological and evolutionary pressures. There are surprisingly few data, however, testing the underlying assumption that the performance of introduced populations, including organism size, reproductive output, and abundance, is enhanced in their introduced compared to their native range. Here, we combined data from published studies to test this hypothesis for 26 plant and 27 animal species that are considered to be invasive. On average, individuals of these 53 species were indeed larger, more fecund, and more abundant in their introduced ranges. The overall mean, however, belied significant variability among species, as roughly half of the investigated species (N = 27) performed similarly when compared to conspecific populations in their native range. Thus, although some invasive species are performing better in their new ranges, the pattern is not universal, and just as many are performing largely the same across ranges.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Paleoecology can provide valuable insights into the ecology of species that complement observation and experiment-based assessments of climate impact dynamics. New paleoecological records (e.g., pollen, macrofossils) from the Italian Peninsula suggest a much wider climatic niche of the important European tree species Abies alba (silver fir) than observed in its present spatial range. To explore this discrepancy between current and past distribution of the species, we analyzed climatic data (temperature, precipitation, frost, humidity, sunshine) and vegetation-independent paleoclimatic reconstructions (e.g., lake levels, chironomids) and use global coupled carbon-cycle climate (NCAR CSM1.4) and dynamic vegetation (LandClim) modeling. The combined evidence suggests that during the mid-Holocene (6000 years ago), prior to humanization of vegetation, A. alba formed forests under conditions that exceeded the modern (1961-1990) upper temperature limit of the species by 5-7°C (July means). Annual precipitation during this natural period was comparable to today (>700-800 mm), with drier summers and wetter winters. In the meso-Mediterranean to sub-Mediterranean forests A. alba co-occurred with thermophilous taxa such as Quercus ilex, Q. pubescens, Olea europaea, Phillyrea, Arbutus, Cistus, Tilia, Ulmus, Acer, Hedera helix, Ilex aquifolium, Taxus, and Vitis. Results from the last interglacial (ca. 130 000-115 000 BP), when human impact was negligible, corroborate the Holocene evidence. Thermophilous Mediterranean A. alba stands became extinct during the last 5000 years when land-use pressure and specifically excessive anthropogenic fire and browsing disturbance increased. Our results imply that the ecology of this key European tree species is not yet well understood. On the basis of the reconstructed realized climatic niche of the species, we anticipate that the future geographic range of A. alba may not contract regardless of migration success, even if climate should become significantly warmer than today with summer temperatures increasing by up to 5-7°C, as long as precipitation does not fall below 700-800 mm/yr, and anthropogenic disturbance (e.g., fire, browsing) does not become excessive. Our finding contradicts recent studies that projected range contractions under global-warming scenarios, but did not factor how millennia of human impacts reduced the realized climatic niche of A. alba.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The Burgundy truffle (Tuber aestivum Vittad.), an ectomycorrhizal fungus living in association with host plants, is one of the most exclusive delicacies. The symbiosis with deciduous oak, beech, and hazel dominates our concept of truffle ecophysiology, whereas potential conifer hosts have rarely been reported. Here, we present morphological and molecular evidence of a wildlife T. aestivum symbiosis with Norway spruce (Picea abies Karst.) and an independent greenhouse inoculation experiment, to confirm our field observation in southwest Germany. A total of 27 out of 50 P. abies seedlings developed T. aestivum ectomycorrhizae with a mean mycorrhization rate of 19.6 %. These findings not only suggest P. abies to be a productive host species under suitable biogeographic conditions but also emphasize the broad ecological amplitude and great symbiotic range of T. aestivum. While challenging common knowledge, this study demonstrates a significant expansion of the species' cultivation potential to the central European regions, where P. abies forests occur on calcareous soils.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Is the online trade with second-hand products changing individual consumer behaviour? What is the sustainability potential of this activity? How can daily energy-consuming routines at the workplace be changed? Do major changes in the course of people's lives represent opportunities to modify their consumer behaviour towards greater sustainability? These are only some of the research questions studied in the focal topic "From Knowledge to Action - New Paths towards Sustainable Consumption" which is funded by the German Federal Ministry of Education and Research (BMBF) as part of the "Social-ecological Research Programme" (SÖF). This book gives an insight into the research results of the ten project groups. Their diversity highlights that there is much more to "sustainable consumption" than the simple purchase of organic or fair trade products.In addition, overarching conceptual and normative issues were treated across the project groups of the focal topic. Developed collaboratively and moderated by the accompanying research project, the results of the synthesis process are also presented here, as for example how the sustainability of individual consumer behaviour can be evaluated,or which theories of action are particularly useful for specific consumer behaviour phenomena.