16 resultados para Temporary pools
Resumo:
The aims of this study were to explore the environmental factors that determine the distribution of plant communities in temporary rock pools and provide a quantitative analysis of vegetation-environment relationships for five study sites on the island of Gavdos, southwest of Crete, Greece. Data from 99 rock pools were collected and analysed using Two-Way Indicator Species Analysis (TWINSPAN), Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) to identify the principal communities and environmental gradients that are linked to community distribution. A total of 46 species belonging to 21 families were recorded within the study area. The dominant families were Labiatae, Gramineae and Compositae while therophytes and chamaephytes were the most frequent life forms. The samples were classified into six community types using TWINSPAN, which were also corroborated by CCA analysis. The principal gradients for vegetation distribution, identified by CCA, were associated with water storage and water retention ability, as expressed by pool perimeter and water depth. Generalised Additive Models (GAMs) were employed to identify responses of four dominant rock pool species to water depth. The resulting species response curves showed niche differentiation in the cases of Callitriche pulchra and Tillaea vaillantii and revealed competition between Zannichellia pedunculata and Chara vulgaris. The use of classification in combination with ordination techniques resulted in a good discrimination between plant communities. Generalised Additive Models are a powerful tool in investigating species response curves to environmental gradients. The methodology adopted can be employed for improving baseline information on plant community ecology and distribution in Mediterranean ephemeral pools.
Resumo:
A poplar short rotation coppice (SRC) grown for the production of bioenergy can combine carbon (C) storage with fossil fuel substitution. Here, we summarize the responses of a poplar (Populus) plantation to 6 yr of free air CO2 enrichment (POP/EUROFACE consisting of two rotation cycles). We show that a poplar plantation growing in nonlimiting light, nutrient and water conditions will significantly increase its productivity in elevated CO2 concentrations ([CO2]). Increased biomass yield resulted from an early growth enhancement and photosynthesis did not acclimate to elevated [CO2]. Sufficient nutrient availability, increased nitrogen use efficiency (NUE) and the large sink capacity of poplars contributed to the sustained increase in C uptake over 6 yr. Additional C taken up in high [CO2] was mainly invested into woody biomass pools. Coppicing increased yield by 66% and partly shifted the extra C uptake in elevated [CO2] to above-ground pools, as fine root biomass declined and its [CO2] stimulation disappeared. Mineral soil C increased equally in ambient and elevated [CO2] during the 6 yr experiment. However, elevated [CO2] increased the stabilization of C in the mineral soil. Increased productivity of a poplar SRC in elevated [CO2] may allow shorter rotation cycles, enhancing the viability of SRC for biofuel production.
Resumo:
Numerous studies have shown that attention is biased toward threatening events. More recent evidence has also found attentional biases for stimuli that are relevant to the current and temporary goals of an individual. We examined whether goal-relevant information still evokes an attentional bias when this information competes with threatening events. In three experiments, participants performed a dot probe task combined with a separate task that induced a temporary goal. The results of Experiment 1 showed that attention was oriented to goal-relevant pictures in the dot probe task when these pictures were simultaneously presented with neutral or threatening pictures. Whether goal-relevant pictures themselves were threatening or neutral did not influence the results. Experiment 2 replicated these findings in a sample of highly trait-anxious participants. Experiment 3 showed that attention was automatically deployed to stimuli relevant to a temporary goal even in the presence of stimuli that signal imminent and genuine threat (i.e., a colored patch signaling the presentation of an aversive noise). These findings further corroborate the conclusion that an individual's current and temporary goals guide early attentional processes
Resumo:
Temporary work has expanded in the last three decades with adverse implications for inequalities. Because temporary workers are a constituency that is unlikely to impose political costs, governments often choose to reduce temporary work regulations. While most European countries have indeed implemented such reforms, France went in the opposite direction, despite having both rigid labour markets and high unemployment. My argument to solve this puzzle is that where replaceability is high, workers in permanent and temporary contracts have overlapping interests, and governments choose to regulate temporary work to protect permanent workers. In turn, replaceability is higher where permanent workers’ skills are general and wage coordination is low. Logistic regression analysis of the determinants of replaceability — and how this affects governments’ reforms of temporary work regulations — supports my argument. Process tracing of French reforms also confirm that the left has tightened temporary work regulations to compensate for the high replaceability.
Resumo:
European labour markets are increasingly divided between insiders in full-time permanent employment and outsiders in precarious work or unemployment. Using quantitative as well as qualitative methods, this thesis investigates the determinants and consequences of labour market policies that target these outsiders in three separate papers. The first paper looks at Active Labour Market Policies (ALMPs) that target the unemployed. It shows that left and right-wing parties choose different types of ALMPs depending on the policy and the welfare regime in which the party is located. These findings reconcile the conflicting theoretical expectations from the Power Resource approach and the insider-outsider theory. The second paper considers the regulation and protection of the temporary work sector. It solves the puzzle of temporary re-regulation in France, which contrasts with most other European countries that have deregulated temporary work. Permanent workers are adversely affected by the expansion of temporary work in France because of general skills and low wage coordination. The interests of temporary and permanent workers for re-regulation therefore overlap in France and left governments have an incentive to re-regulate the sector. The third paper then investigates what determines inequality between median and bottom income workers. It shows that non-inclusive economic coordination increases inequality in the absence of compensating institutions such as minimum wage regulation. The deregulation of temporary work as well as spending on employment incentives and rehabilitation also has adverse effects on inequality. Thus, policies that target outsiders have important economic effects on the rest of the workforce. Three broader contributions can be identified. First, welfare state policies may not always be in the interests of labour, so left parties may not always promote them. Second, the interests of insiders and outsiders are not necessarily at odds. Third, economic coordination may not be conducive to egalitarianism where it is not inclusive.
Resumo:
Seven catchments of diverse size in Mediterranean Europe were investigated in order to understand the main aspects of their hydrological functioning. The methods included the analysis of daily and monthly precipitation, monthly potential evapotranspiration rates, flow duration curves, rainfall runoff relationships and catchment internal data for the smaller and more instrumented catchments. The results showed that the catchments were less dry than initially considered. Only one of them was really semi-arid throughout the year. All the remaining catchments showed wet seasons when precipitation exceeded potential evapotrans-piration, allowing aquifer recharge, wet runoff generation mechanisms and relevant baseflow contribution. Nevertheless, local infiltration excess (Hortonian) overland flow was inferred during summer storms in some catchments and urban overland flow in some others. The roles of karstic groundwater, human disturbance and low winter temperatures were identified as having an important impact on the hydrological regime in some of the catchments.
Resumo:
This article investigates the determinants of union inclusiveness towards agency workers in Western Europe, using an index which combines unionization rates with dimensions of collective agreements covering agency workers. Using fuzzy-set Qualitative Comparative Analysis, we identify two combinations of conditions leading to inclusiveness: the ‘Northern path’ includes high union density, high bargaining coverage and high union authority, and is consistent with the power resources approach. The ‘Southern path’ combines high union authority, high bargaining coverage, statutory regulations of agency work and working-class orientation, showing that ideology rather than institutional incentives shapes union strategies towards the marginal workforce.
Resumo:
This chapter focuses upon the careers of temporary workers. Temporary employment for many workers presents a route to permanent employment. Other workers, however, get trapped into temporary employment or cycle between unstable jobs and spells of unemployment. Predictors of such transitions are multiple. We selected two broad categories, namely perceived employability from the area of career research and health and well-being from the area of occupational health and well-being research. The overall conclusion is that the association between temporary employment and both perceived employability and health and well-being is inconclusive. This suggests that there are boundary conditions that may make some temporary workers successful and others not. Risk factors include dynamics related to the dual labor market, including lower job quality, lower investments on the part of employers, and negative stereotyping of temporary workers as second-class citizens. On the positive side, many temporary workers have learned to manage their careers in the sense that they invest in training and in continuous job search.
Resumo:
The building industry is often berated for its short comings in meeting up with the demand for the provision of new housing. Addressing the need for new housing stock is a challenge that has led to debates among professional bodies, the construction sector, housing industry and government. The introduction of new manufacturing technologies is often offered as a solution, but the challenges of increasing the amount of off-site construction in residential building are well known and well-rehearsed. The modern flying factory (MFF) is a concept that involves the manufacture of specific components or modules in temporary off- or near- site locations using relatively simple and quick to set up and dismantle technologies and processes. The aim is to produce short batches and hence achieve some of the benefits of off-site manufacture on a much smaller scale than in dedicated factory environments. A case study of a modern flying factory being set up to produce pre-assembled utility cupboards for a large residential development in London is presented, involving participant observation and informal interviews with key actors on the design and operationalising of the process. The case reveals that although there are costs, efficiency and health and safety benefits to using MFF approaches, there are also challenges to overcome over the time required to set up and establish the process for relatively short runs, and in evaluating whether the MFF or traditional site based production is most effective for particular aspects of projects.