1,023 research outputs found
Conflicts over wildlife conservation: learning from the reintroduction of beavers in Scotland
1. Species reintroductions have become a common conservation tool, but they can be controversial and may generate social conflicts.
2. We examine the social dimension of beaver reintroduction in Scotland to understand the issue, the potential for, and impact of, conflict between groups or individuals with differing views on beavers and reintroductions.
3. Using a literature review and semiâstructured interviews, we studied planned and unplanned beaver reintroductions to three contrasting landscapes in Scotland: in Knapdale, the reintroduction was planned and scienceâled, whereas in Tayside and the Highlands, the reintroductions were accidental and/or illegal.
4. Our results highlight the context dependency and complexity of reintroductions. Nationally, the reintroduction of beavers has not become a conflict. At the local scale, we found the Tayside situation to be a conflict with major consequences on the debate at the national scale. While there were no conflicts in the Highlands and Knapdale, the reintroduction remains controversial.
5. The level of conflict depended on the reintroduction process, relationships between stakeholders and their perspectives on their role in nature, their perceptions of landscapes, and the potential issue of lack of control and uncertainty around reintroductions.
6. Based on these findings, the study outlines lessons learned in terms of management, guidelines and implications for future species reintroductions. We argue that to prevent future conflicts over reintroductions, processes must go beyond addressing the effects of reintroduced species on the environment and people's perceptions and acceptance of these species. Reintroduction processes require engagement in effective discussions which involve all actual and potential stakeholders to agree on broad and longâterm conservation plans at the landscape scale
An estimation of gravel mobility over an alpine river gravel bar (Arc en Maurienne, France) using PIT-tag tracers
River morphodynamics and sediment transportRiver morphology and morphodynamic
On the stability of standing waves of Klein-Gordon equations in a semiclassical regime
We investigate the orbital stability and instability of standing waves for
two classes of Klein-Gordon equations in the semi-classical regime.Comment: 9 page
Contrasted sediment processes and morphological adjustments in three successive cutoff meanders of the Danube Delta
Since the 1980s intensive anthropogenic disturbances have affected the channel of the St. George branch, the southern distributary of the Danube River. The meander cutoff programme since 1984â1988 induced different hydrosedimentary impacts on the local distribution of river flow velocities, discharge, and sediment fluxes between the former meanders and the man-made canals (Ichim and Radoane, 1986; Popa, 1997; Panin, 2003). This paper selects three large cutoff meander reaches of the St. George branch (the Mahmudia, DunavÄĆŁ de Sus, and DunavÄĆŁ de Josmeanders noted here asM1,M2, andM3, respectively) as an example to analyse the human impact in the Danube River delta. The diversion of the flow induces strong modifications by acceleration of the fluxes through the artificial canals combined with dramatically enhanced deposition in the former meander where it was observed in two cases (M1 and M3) with slight modifications in M2. An exceptional flood that occurred in April 2006 offered a good opportunity for scanning different cross sections of the meander systems. Bathymetry, flow velocity, suspended-load concentration, and liquid and solid discharge data were acquired throughout several cross sections of both natural channels and artificial canals of the three cutoffs, using acoustic Doppler current profiler (ADCP) technology, in order to investigate the distribution of the flowand sediment and its impact on the hydrosedimentary processes in each channelized reach and adjacent former meander. Therefore, the results obtained during the 2006 flood were referred to a long-term evolution (1970â2006), analysed by GIS techniques
Automatic plankton quantification using deep features
The study of marine plankton data is vital to monitor the health of the worldâs oceans. In recent decades, automatic plankton recognition systems have proved useful to address the vast amount of data collected by specially engineered in situ digital imaging systems. At the beginning, these systems were developed and put into operation using traditional automatic classification techniques, which were fed with handdesigned local image descriptors (such as Fourier features), obtaining quite successful results. In the past few years, there have been many advances in the computer vision community with the rebirth of neural networks. In this paper, we leverage how descriptors computed using Convolutional Neural Networks (CNNs) trained with out-of-domain data are useful to replace hand-designed descriptors in the task of estimating the prevalence of each plankton class in a water sample. To achieve this goal, we have designed a broad set of experiments that show how effective these deep features are when working in combination with state-of-the-art quantification algorithms
The inverse scattering problem at fixed energy based on the Marchenko equation for an auxiliary Sturm-Liouville operator
A new approach is proposed to the solution of the quantum mechanical inverse
scattering problem at fixed energy. The method relates the fixed energy phase
shifts to those arising in an auxiliary Sturm-Liouville problem via the
interpolation theory of the Weyl-Titchmarsh m-function. Then a Marchenko
equation is solved to obtain the potential.Comment: 6 pages, 8 eps figure
Multi-solitary waves for the nonlinear Klein-Gordon equation
International audienceWe consider the nonlinear Klein-Gordon equation in . We call multi-solitary waves a solution behaving at large time as a sum of boosted standing waves. Our main result is the existence of such multi-solitary waves, provided the composing boosted standing waves are stable. It is obtained by solving the equation backward in time around a sequence of approximate multi-solitary waves and showing convergence to a solution with the desired property. The main ingredients of the proof are finite speed of propagation, variational characterizations of the profiles, modulation theory and energy estimates
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