Colonial Ascidian Dispersal: What are the effects of adult population density and isolation on recruitment?

29 pagesInvasive species are thought to be one of the largest ecological threats to healthy ecosystems today. This paper is an attempt to show how anthropogenic transport of species with short dispersal distances is the most important factor in their colonization of new areas. In the Charleston, Oregon marina three study sites were set up to attempt to show the significance of isolation and adult population density on the recruitment of colonial ascidians, an encrusting member of the fouling community. Significant results were found supporting the hypothesis that greater adult population density results in increased recruitment. The second hypothesis of isolation decreasing the recruitment of colonial ascidians was not supported with significant results

Wood dynamics in headwater streams of the Colorado Rocky Mountains

Peer reviewedPublisher PD

A flume experiment on wood storage and remobilization in braided river systems

This work investigates wood dynamics in braided streams through physical modelling in a mobile bed laboratory flume, with the specific objective to characterize wood storage and turnover as a function of wood input rate and of wood element type. Three parallel channels (1.7 m wide, 10 m long) filled with uniform sand were used to reproduce braided networks with constant water discharge and sediment feeding. Wood dowels with and without simplified root wads were regularly added at the upstream end of each flume at different input rates, with a 1:2:3 ratio between the three flumes. Temporal evolution of wood deposition patterns and remobilization rates were monitored by a series of vertical images that permitted the recognition of individual logs. Results show that wood tends to disperse in generally small accumulations ( 10 elements) that are less prone to remobilization. Presence of root wads seems to play a minor role in wood deposition, but it reduces the average travel distance of logs. Turnover rates of logs were similar in the three flumes, independently of wood input rate and largely resembling the turnover rate of exposed bars. For the simulated conditions, significant effects of wood on bed morphology were not observed, suggesting that interactions with fine sediments and living vegetation are crucial to form large, stable wood jams able to bring about relevant morphological change

Динамика уровня лептина, модулятора роста TGF-β1 и провоспалительного цитокина IL-1β в системном кровотоке у больных псориазом с избыточной массой тела под влиянием системной терапии ожирения

У хворих шкірними формами псоріазу з ожирінням і гіперлептинемією вивчена динаміка рівня цитокінів TGF-β1 і IL-1β під впливом системної терапії ожиріння з використанням акарбози (Глюкобай). Встановлено, що включення в комплексну терапію псоріазу акарбози (Глюкобай) дозволяє статистично значимо знизити гіперлептинемію і рівень прозапального цитокіну IL-1β. Достовірного впливу лікування акарбозою (Глюкобай) на рівень активної форми TGF-β1 у хворих на псоріаз не виявивлено.In patients with cutaneous forms of psoriasis with obesity and hyperleptinemia the dynamics of cytokines TGF-β1 and IL-1β under the influence of systemic treatment of obesity with the use of acarbose (Glyukobay) were studied. It is established that added of acarbose (glyukobay) to complex treatment of psoriasis can significantly reduce hyperleptinemia and the level of pro-inflammatory cytokine IL-1β. There were no significant effect of acarbose treatment (Glyukobay) at the level of the active form of TGF-β1 in patients with psoriasis

Meandering rivers in modern desert basins: Implications for channel planform controls and prevegetation rivers

The influence of biotic processes in controlling the development of meandering channels in fluvial systems is controversial. The majority of the depositional history of the Earth's continents was devoid of significant biogeomorphic interactions, particularly those between vegetation and sedimentation processes. The prevailing perspective has been that prevegetation meandering channels rarely developed and that rivers with braided planforms dominated. However, recently acquired data demonstrate that meandering channel planforms are more widely preserved in prevegetation fluvial successions than previously thought. Understanding the role of prevailing fluvial dynamics in non- and poorly vegetated environments must rely on actualistic models derived from presently active rivers developed in sedimentary basins subject to desert-climate settings, the sparsest vegetated regions experiencing active sedimentation on Earth. These systems have fluvial depositional settings that most closely resemble those present in prevegetation (and extra-terrestrial) environments. Here, we present an analysis based on satellite imagery which reveals that rivers with meandering channel planforms are common in modern sedimentary basins in desert settings. Morphometric analysis of meandering fluvial channel behaviour, where vegetation is absent or highly restricted, shows that modern sparsely and non-vegetated meandering rivers occur across a range of slope gradients and basin settings, and possess a broad range of channel and meander-belt dimensions. The importance of meandering rivers in modern desert settings suggests that their abundance is likely underestimated in the prevegetation rock record, and models for recognition of their deposits need to be improved

Assessing and mitigating large wood-related hazards in mountain streams: recent approaches

The assessment and mitigation of floods in mountain streams, when large wood (LW) is transported, pose several challenges. The process chain consisting of flood propagation, LW recruitment, entrainment, transport, and entrapment triggers, at critical sections such as bridges, unexpected and exacerbated impacts to the exposed built environment. We provide a review on the recent advances in modelling LW dynamics during extreme river floods through computational approaches. Moreover, we describe how scaled flume experiments can enhance process understanding at critical flow sections such as bridges to address risk mitigation problems. Additionally, we present a framework based on Formative Scenario Analysis (FSA) to allow for expert knowledge integration and to subsequently derive consistent hazard process scenarios in steep mountain streams where the application of computational approaches is less reliable. Finally, we discuss how the application of the presented set of assessment methods can support integral flood risk management by explicitly considering LW dynamics since the effectiveness of mitigation critically depends on the acquired process understanding