Search results for "forest"

I fattori topografici della USLE e la carta dell’erosione massima

2008

Voluntary agreements in protecting privately owned forests in Finland — To buy or to lease?

2008

Abstract A voluntary conservation approach may reveal environmentally minded landowners who are willing to protect their lands with a compensation that is lower than the market price based compensation. Consequently, voluntary conservation programs may induce lower costs than traditional obligatory programs, such as a land taking. We compared the costs accrued from land purchasing with those from temporal land leasing. The costs included both direct costs, such as fees of land acquisition and compensation payments in land leasing, and transaction costs. We used a data set from a Finnish pilot program called Trading in Natural Values (TNV). In this new practice landowners and the authority t…

Effects of dietary administration of fenugreek seeds, alone or in combination with probiotics, on growth performance parameters, humoral immune respo…

2016

The use of immunostimulants is considered a promising preventive practice that may help to maintain animal welfare and a healthy environment, while increasing production and providing higher profits. The purpose of this study was to evaluate the effects on gilthead seabream (Sparus aurata L.) of the dietary administration of fenugreek (Trigonella foenum graecum) seeds, alone or combined with one of the following probiotic strains: Bacillus licheniformis (TSB27), Lactobacillus plantarum or Bacillus subtilis (B46). Gilthead seabream were fed a control or one of the supplemented diets for 3 weeks. The effects of these supplemented diets on growth performance parameters and the humoral immune r…

In vitro cytokine profile revealed differences from dorsal and ventral skin susceptibility to pathogen-probiotic interaction in gilthead seabream

2016

Skin is the first barrier of defense on fish, which is crucial to protection against different stressors, including pathogens. Skin samples obtained from dorsal and ventral part of Sparus aurata specimens were incubated with Photobacterium damselae subsp. piscicida (a pathogen for this fish species), with Shewanella putrefaciens Pdp11 (a probiotic bacteria isolated from healthy gilthead seabream skin) or with both bacteria. The gene expression profile of nine cytokines (il1b, tnfa, il6, il7, il8, il15, il18, il10 and tgfb) was studied by qPCR in all the skin samples. The present findings revealed different patterns of cytokine profile in dorsal and ventral skin of gilthead seabream, which c…

Assessing Spillover Effects of Spatial Policies with Semiparametric Zero-Inflated Models and Random Forests

2021

The aim of this work is to estimate the variation over time of the spatial spillover effects of a public policy that was devoted to boost rural development in France over the period 1993–2002. At a micro data level, it is often observed that the dependent variable, such as local employment in a municipality, does not vary along time, so that we face a kind of zero inflated phenomenon that cannot be dealt with a classical continuous response model or propensity score approaches. We consider two recent non parametric techniques that are able to deal with that estimation issue. The first approach consists in fitting two generalized additive models to estimate both the probability of no variati…

A first contribution to the cryptogamic flora of “Bosco Pomieri” (Northern Sicily)

2020

This is the first contribution to the cryptogamic flora (algae, bryophytes, fungi and lichens) of the “Bosco Pomieri”, an old-growth forest included in the Madonie Regional Park (N-Sicily). This area presents a significantly high biodiversity (41 algae, 41 bryophytes, 141 fungi, and 105 lichens) and also hosts several taxa of high biogeographic value.

Analyzing turbulence in gravel bed channels

2005

In this paper, the results of an experimental investigation of the turbulence intensity in gravel bed channels are described. The runs were carried out by measuring, with an acoustic Doppler velocimeter, the turbulence intensity profile along six verticals of a given cross section in a laboratory flume. The analysis of the measured intensity distributions has shown the existence of two different regions, above and below the tops of the roughness elements, in which different intensity profiles occur. Furthermore, the measured profiles have shown a maximum of the turbulence intensity that decreases for increasing values of the roughness height, confirming that the turbulence damping efficienc…

New Flow-Resistance Law for Steep Mountain Streams Based on Velocity Profile

2017

This paper deduces a new flow-resistance equation for open-channel flow applying dimensional analysis and self-similarity theory. The incomplete self-similarity hypothesis is used to establish the flow velocity distribution whose integration gives the theoretical expression of the Darcy-Weisbach friction factor. The theoretical resistance equation then is tested by the available field measurements of flow velocity, water depth, river width and bed slope carried out in 653 reaches of several Canadian mountain streams. A relationship between the G function of the velocity profile and the channel slope and the flow Froude number is also established. The analysis shows that the Darcy- Weisbach …

Flow Resistance in Step-Pool Rills

2017

Rills evolve morphologically, and the adjustment of rill channel geometry to flow affects the relationships among velocity, discharge, and slope. The resistance to flow in step-pool rills is mainly due to form-induced mechanisms and, in comparison, grain resistance is of minor significance. Previous studies on rill flow resistance have been performed exclusively for grainresistance conditions and use a stream flow equation. In this study, a new flow resistance equation, deduced by applying dimensional analysis and self-similarity theory, was applied to rill flow in step-pool channels. First, the incomplete self-similarity hypothesis was used for establishing a power flow velocity profile wh…

Slope threshold for overland flow resistance on sandy soils

2021

Recent research on rill flows recognised that an 18% slope can be used to distinguish between ‘gentle’ and ‘steep’ slope cases for the detected differences in hydraulic (flow depth and velocity) and sediment transport variables (flow transport capacity, actual sediment load). The effects of slope on flow velocity, friction factor and transport capacity and their interactions affect process-based erosion modelling. The main aim of this paper is to investigate, for the first time, how slope affects the overland flow resistance on sandy soils, which are characterised by loose particles readily available to be transported and deposited. Using literature measurements carried out in sandy soils f…