Search results for " stream"

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.

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 …

Regional flow duration curves for ungauged sites in Sicily

2011

Abstract. Flow duration curves are simple and powerful tools to deal with many hydrological and environmental problems related to water quality assessment, water-use assessment and water allocation. Unfortunately the scarcity of streamflow data enables the use of these instruments only for gauged basins. A regional model is developed here for estimating flow duration curves at ungauged basins in Sicily, Italy. Due to the complex ephemeral behaviour of the examined region, this study distinguishes dry periods, when flows are zero, from wet periods using a three parameters power law to describe the frequency distribution of flows. A large dataset of streamflows has been analysed and the param…

Mise en évidence d’une dynamique de fleuves de glace durant la glaciation ordovicienne par l’enregistrement géomorphologique

2007

On Contemporary Ice streams the most important factor controlling polar ice-sheet sheet stability and ice flowing occurs in ice streams. On Pleistocene Ice Sheet, Ice stream can be located using several geomorphologic criteria predict from known characteristic of contemporary ice streams, these criteria defining the conceptual Ice Stream land system model. But nowadays, during fossil glaciations, ice streams characterization is still poorly documented and only few studies illustrate fast ice velocity. In this work, we characterize geomorphological markers of ice stream activity in order to define the Ordovician ice stream glacial landsystem. The study area is located in Sahara from Niger to…

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…

Subglacial bedforms of the Zemgale Ice Lobe, south-eastern Baltic

2015

Abstract Presented in this paper are the results of the mapping of ∼6600 subglacial bedforms of the Zemgale Ice Lobe (ZIL), their composition and internal structure in the south-eastern Baltic region. Topographic maps at scale 1:10,000 were mainly used to map bedforms in Latvia, while a digital elevation model with cell size of 5 m was used for North Central Lithuania. The ZIL operated during the deglaciation of the Late Weichselian Scandinavian Ice Sheet (SIS), at least in the Middle Lithuanian and North Lithuanian glacial phases, and created a subglacial landform assemblage consisting of glacial lineations such as drumlins, mega-flutings, Mega Scale Glacial Lineations (MSGLs) and transver…

Reconciling time, space and function: a new dorsal-ventral stream model of sentence comprehension.

2013

We present a new dorsal–ventral stream framework for language comprehension which unifies basic neurobiological assumptions (Rauschecker & Scott, 2009) with a cross-linguistic neurocognitive sentence comprehension model (eADM; Bornkessel & Schlesewsky, 2006). The dissociation between (time-dependent)syntactic structure-building and (time-independent) sentence interpretation assumed within thee ADM provides a basis for the division of labour between the dorsal and ventral streams in comprehension.We posit that the ventral stream performs time-independent unifications of conceptual schemata,serving to create auditory objects of increasing complexity. The dorsal stream engages in the time-depe…

New insights on ice dynamics from analysis of terrain of Latvia

2019

The Microbiota Promotes Arterial Thrombosis in Low-Density Lipoprotein Receptor-Deficient Mice

2019

Our results demonstrate a functional role for the commensal microbiota in atherothrombosis. In a ferric chloride injury model of the carotid artery, GF C57BL/6J mice had increased occlusion times compared to colonized controls. Interestingly, in late atherosclerosis, HFD-fed GF Ldlr−/− mice had reduced plaque rupture-induced thrombus growth in the carotid artery and diminished ex vivo thrombus formation under arterial flow conditions.

Dynamic Changes in Ultrastructure of the Primary Cilium in Migrating Neuroblasts in the Postnatal Brain

2019

New neurons, referred to as neuroblasts, are continuously generated in the ventricular-subventricular zone of the brain throughout an animal's life. These neuroblasts are characterized by their unique potential for proliferation, formation of chain-like cell aggregates, and long-distance and high-speed migration through the rostral migratory stream (RMS) toward the olfactory bulb (OB), where they decelerate and differentiate into mature interneurons. The dynamic changes of ultrastructural features in postnatal-born neuroblasts during migration are not yet fully understood. Here we report the presence of a primary cilium, and its ultrastructural morphology and spatiotemporal dynamics, in mig…