Search results for " streams"
showing 10 items of 28 documents
Circumventing deadlock through venue-shopping: Why there is more than just talk in US immigration politics in times of economic crisis
2016
This article addresses the question of how the financial and economic crisis that hit the US in the late 2000s impacted immigration policies. We find that the crisis has not significantly changed dynamics. Instead, it has highlighted and aggravated persisting trends. Drawing on Kingdon’s multiple streams model and combining it with the notion of two-level games, we find that while the policy stream and the problem stream would call for both restrictive and liberalising changes, the political stream impedes change: The fact that Congress has been divided for a long time over Comprehensive Immigration Reform (CIR) impedes any restrictive or liberalising changes. With problems resulting from c…
Analysis of rill step–pool morphology and its comparison with stream case
2021
In this paper, the morphology of step–pool features is analysed using rill measurements and literature data for streams. Close-range photogrammetry was used to carry out ground measurements on rills with step–pool units, shaped on a plot having slope equal to 14, 15, 22, 24 and 26%. Data were used to compare the relationships between H/L, in which H is the step height and L is the step length, and the mean gradient of the step–pool sequence, Sm, for streams or the slope of the step–pool unit, S, for rills. The relationship of H/L against Sm is widely used to test the occurrence of the maximum flow resistance condition in streams, which is associated with the range 1 ≤ (H/L)/Sm ≤ 2. Further …
Las crecidas en ramblas valencianas mediterráneas
2001
This paper takes into account the characterisation of ephemeral stream hydrology from Mediterranean environments. The heavy floods that these countries suffer are due to firstly, the physical watershed features (steep slopes, scarced vegetation cover and thin soils) and, secondly, to the intense and variable rainfall. Large quantities of precipitation fall in a matter of hours, or even minutes, over very steep catchments, causing catastrophic flash-floods, with very pointed hydrographs and short time lags. Using hydrological daily data from the Rambla de la Viuda basin and five-minute data from both Barranc de Carraixet and Rambla de Poyo basins, we have analysed the rainfall- runoff proces…
Ecology, fisheries and management of wild brown trout populations in boreal inland waters
2010
Eutrophication of aquatic ecosystems is an increasing problem, especially threatening small and shallow freshwater lakes. While the extreme inputs of nutrients (phosphorus and nitrogen) can nowadays be reduced and controlled rather efficiently, additional measures to reverse eutrophication may be needed. These often involve biomanipulation, typically mass removal of cyprinid fish. However, the success of biomanipulations has many times been limited or short lived. The reasons for this are not well known, perhaps because the more subtle impacts of biomanipulation on the ecosystem-wide processes of lakes have not been thoroughly studied. Natural abundance stable isotopes may provide a cost-ef…
On the Classification of Dynamical Data Streams Using Novel “Anti–Bayesian” Techniques
2018
The classification of dynamical data streams is among the most complex problems encountered in classification. This is, firstly, because the distribution of the data streams is non-stationary, and it changes without any prior “warning”. Secondly, the manner in which it changes is also unknown. Thirdly, and more interestingly, the model operates with the assumption that the correct classes of previously-classified patterns become available at a juncture after their appearance. This paper pioneers the use of unreported novel schemes that can classify such dynamical data streams by invoking the recently-introduced “Anti- Bayesian” (AB) techniques. Contrary to the Bayesian paradigm, that compar…
LA VIABILITÀ MINORE NELLA SICILIA CENTRO-MERIDIONALE: IL COMPRENSORIO DI CIGNANA TRA LA VIA SELINUNTINA E LA CATINA-AGRIGENTUM
2021
Obiettivo del contributo è esaminare il sistema stradale di età antica, con un’attenzione particolare rivolta alle vie secondarie, in un ben definito comprensorio della Sicilia meridionale, l’area del Progetto Cignana, pochi km ad est di Agrigento. Si tratta di cogliere non tanto i caratteri della viabilità di lunga percorrenza (la via Selinuntina e la via Catina-Agrigentum) quanto piuttosto le interconnessioni tra i principali assi viari, la rete secondaria (spesso attestata lungo i principali corsi d’acqua), gli insediamenti rurali e gli approdi sulla costa. This paper is aimed to analyze the ancient road system in a selected area of the Southern Sicily, between Agrigento and Licata (Cign…
Diversity and distribution of Phytophthora species in protected natural areas in Sicily
2019
: The aim of this study was to investigate the occurrence, diversity, and distribution of Phytophthora species in Protected Natural Areas (PNAs), including forest stands, rivers, and riparian ecosystems, in Sicily (Italy), and assessing correlations with natural vegetation and host plants. Fifteen forest stands and 14 rivers in 10 Sicilian PNAs were studied. Phytophthora isolations from soil and stream water were performed using leaf baitings. Isolates were identified using both morphological characters and sequence analysis of the internal transcribed spacer (ITS) region. A rich community of 20 Phytophthora species from eight phylogenetic clades, including three new Phytophthora taxa, was …
A critical review on the implementation of static data sampling techniques to detect network attacks
2021
International audience; Given that the Internet traffic speed and volume are growing at a rapid pace, monitoring the network in a real-time manner has introduced several issues in terms of computing and storage capabilities. Fast processing of traffic data and early warnings on the detected attacks are required while maintaining a single pass over the traffic measurements. To palliate these problems, one can reduce the amount of traffic to be processed by using a sampling technique and detect the attacks based on the sampled traffic. Different parameters have an impact on the efficiency of this process, mainly, the applied sampling policy and sampling ratio. In this paper, we investigate th…
545. Un período fundamental para la climatología española: el “descubrimiento” de la circulación atmosférica en altitud, 1950-1980
2016
El período que transcurre entre los años 1950 y 1980 resulta decisivo para la consolidación de la climatología española. Los trabajos de una serie de geógrafos españoles (López Gómez, García Fernández, Gil Olcina, Burriel de Orueta, Albentosa Sánchez y Capel Molina) se convertirán en referencias básicas al presentar en nuestro país los avances sobre la circulación atmosférica en las capas altas de la troposfera que se desarrollan después de la 2a Guerra Mundial en Estados Unidos y otros países europeos. Este trabajo analiza el contexto científico en el que tiene lugar el “descubrimiento” de la circulación atmosférica en altitud por parte de la geografía española y su repercusión para la mej…
Particularities of Grey Alder (Alnus incana) Stands in Riparian Galleries Along Streams of the Southern Transylvanian Tableland (Romania)
2019
Abstract Grey Alder (Alnus incana (L.) Moench.) stands are distributed in the Carpathian area on alluvial deposits with sediments of different grain size as galleries along rivers and streams of the sub-montane to the middle montane level. The geological structure (Tertiary sedimentary deposits) in relation to the hydromorphological processes is the base for the structure of the stream valleys, which are in part very deep. Under the special microclimate of these deeper stream stretches with lower temperatures there are favourable conditions for the development of grey alder stands.