90 research outputs found

    ContribuciĂłn al conocimiento de crustĂĄceos y rotĂ­feros del Delta del Ebro

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    Hydrologic and landscape changes in the Middle Ebro River (NE Spain): implications for restoration and management

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    The changes of landscape (1927–2003), discharge regime and anthropic activities with the river-floodplain of one reach at the Middle Ebro River (NE Spain) were investigated with the objective to identify the factors that best explain the natural ecotope succession and propose a realistic restoration option with consideration of the landscape dynamics during the last century and the socio-economic context. Our results indicate that hydrological and landscape patterns have been dramatically changed during the last century as a consequence of human alteration of the fluvial dynamics within the studied reach. The magnitude and variability of river discharge events have decreased at the end of the last century, and flood protection structures have disrupted the river floodplain connectivity. As a result, the succesional pathways of riparian ecotopes have been heavily modified because natural rejuvenation no longer takes place, resulting in decreased landscape diversity. It is apparent from these data that floodplain restoration must be incorporated as a significant factor into river management plans if a more natural functioning wants to be retrieved. The ecotope structure and dynamics of the 1927–1957 period should be adopted as the guiding image, whereas current hydrologic and landscape (dykes, raised surfaces) patterns should be considered. Under the current socio-economic context, the more realistic option seems to create a dynamic river corridor reallocating dykes and lowering floodplain heights. The extent of this river corridor should adapt to the restored flow regime, although periodic economic investments could be an option if the desired self-sustained dynamism is not reached

    Nurse species could facilitate the recruitment of mangrove seedlings after hydrological rehabilitation

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    Changes in hydrology are one of the main causes of mangrove degradation; however, the reforestation of mangrove has been the main restoration activity and very little information on how pioneer species can facilitate the colonization and development of the mangrove species is available. After carrying out a water reconnection as the sole restoration action, secondary succession has occurred in the mangrove rehabilitation area of Celestun (Yucatan, SE Mexico). Two pioneer species, Batis maritima and Salicornia virginica were observed in plots with different coverage (0%, 20%, 100%) where the three natural mangrove species were established, with Laguncularia racemosa as the dominant species in density. The greatest interstitial mean salinity (79.9 g/kg) was recorded in the plots with 20% cover, while the lowest salinity (40.7 g/kg) was recorded in the plots with 100% of coverage. At the end of sampling period nutrient content (carbon, nitrogen and phosphorus) and organic matter in the sediment were greatest in the plots with 100% cover, whereas the lowest concentrations were observed in the site devoid of vegetation. The percentage cover of S. virginica and B. maritima changed over time; in the plot that started with 100% cover it decreased until it disappeared at the end of the study period, whereas it increased in the plots with 20% and 0% cover. This study shows that B. maritima and S. virginica has a function as "facilitator species" initially colonizing the bare soil and modifying its conditions (decreasing interstitial salinity and increasing nutrient), which favored colonization and growing of mangrove seedlings

    From national monopoly to Multinational Corporation: how regulation shaped the road towards telecommunications internationalization

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    One of the consequences of major regulatory reform of the telecommunications sector from the end of the 1970s – particularly, privatization, liberalization and deregulation – was the establishment of a new business environment which permitted former national telecommunications monopolies to expand abroad. From the 1990s, a number of these firms, particularly those based in Europe, joined the rankings of the world’s leading Multinational Corporations. Their internationalization was uneven, however: while some firms internationalised strongly, others ventured abroad much slower. This article explores how the regulatory framework within which telecommunications incumbents evolved over the long-term shaped their subsequent, uneven, paths to internationalization. Two case studies representing ®maximum variation® are selected: Telefónica, whose early and unrelenting expansion transformed it into one of the world’s most international of Multinational Corporations, and BT, whose overseas ventures failed and, with eroding domestic market share, forced the firm to partially retreat, becoming the least international of the large European incumbents. Long-term ownership, access to capital, management style and exposure to liberalization strongly influenced firms’ approaches to internationalizatio

    Regulating and Deregulating the Public Utilities 1830-2010

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    History can provide invaluable insights into important issues of the economic and social regulation of utilities, and offer lessons towards future debates. But the history of utility regulation – which speaks of changing, diverse and complex experiences around the world – was, unfortunately, sidelined or marginalised when economists and policymakers enthusiastically embraced the question of how to reform the utilities from the 1970s. This paper provides an overview of the three, overarching, `waves' of utility regulation from the nineteenth century to the present, documenting how, when and why the ways in which the roles of the state, the market and firms altered over time. It then contextualises and explains the main contributions of each of the papers included in this special issue of Business History, which cover energy, communications, water, transportation and other urban infrastructure regulation, across Western Europe, the United States and Australia

    Angiotensin-Neprilysin inhibition in heart failure with preserved ejection fraction

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    Background: the angiotensin receptor-neprilysin inhibitor sacubitril-valsartan led to a reduced risk of hospitalization for heart failure or death from cardiovascular causes among patients with heart failure and reduced ejection fraction. The effect of angiotensin receptor-neprilysin inhibition in patients with heart failure with preserved ejection fraction is unclear. Methods: we randomly assigned 4822 patients with New York Heart Association (NYHA) class II to IV heart failure, ejection fraction of 45% or higher, elevated level of natriuretic peptides, and structural heart disease to receive sacubitril-valsartan (target dose, 97 mg of sacubitril with 103 mg of valsartan twice daily) or valsartan (target dose, 160 mg twice daily). The primary outcome was a composite of total hospitalizations for heart failure and death from cardiovascular causes. Primary outcome components, secondary outcomes (including NYHA class change, worsening renal function, and change in Kansas City Cardiomyopathy Questionnaire [KCCQ] clinical summary score [scale, 0 to 100, with higher scores indicating fewer symptoms and physical limitations]), and safety were also assessed. Results: there were 894 primary events in 526 patients in the sacubitril-valsartan group and 1009 primary events in 557 patients in the valsartan group (rate ratio, 0.87; 95% confidence interval [CI], 0.75 to 1.01; P = 0.06). The incidence of death from cardiovascular causes was 8.5% in the sacubitril-valsartan group and 8.9% in the valsartan group (hazard ratio, 0.95; 95% CI, 0.79 to 1.16); there were 690 and 797 total hospitalizations for heart failure, respectively (rate ratio, 0.85; 95% CI, 0.72 to 1.00). NYHA class improved in 15.0% of the patients in the sacubitril-valsartan group and in 12.6% of those in the valsartan group (odds ratio, 1.45; 95% CI, 1.13 to 1.86); renal function worsened in 1.4% and 2.7%, respectively (hazard ratio, 0.50; 95% CI, 0.33 to 0.77). The mean change in the KCCQ clinical summary score at 8 months was 1.0 point (95% CI, 0.0 to 2.1) higher in the sacubitril-valsartan group. Patients in the sacubitril-valsartan group had a higher incidence of hypotension and angioedema and a lower incidence of hyperkalemia. Among 12 prespecified subgroups, there was suggestion of heterogeneity with possible benefit with sacubitril-valsartan in patients with lower ejection fraction and in women. Conclusions: sacubitril-valsartan did not result in a significantly lower rate of total hospitalizations for heart failure and death from cardiovascular causes among patients with heart failure and an ejection fraction of 45% or higher. (Funded by Novartis; PARAGON-HF ClinicalTrials.gov number, NCT01920711.)
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