Various factors, such as habitat availability, competition for space, predation, temperature, nutrient supplies, presence of waterfalls, flow variability and water quality, control the abundance, ...distribution and productivity of stream-dwelling organisms. Each of these factors can influence the response of the density of organisms to a specific environmental gradient, inflating variability and making difficult to understand the possible causal relationship. In our study, we used quantile regression mixed models and Akaike’s information criterion as an indicator of goodness to examine two different datasets, one belonging to Italy and one belonging to Finland, and to detect the limiting action of selected environmental variables. In the Italian dataset, we studied the relationships among five macroinvertebrate families and three physical habitat characteristics (water velocity, depth and substratum size); in the Finnish dataset the relationships between taxa richness and 16 environmental characteristics (chemical and physical). We found limiting relationships in both datasets and validated all of them on different datasets. These relationships are quantitative and can be used to predict the range of macroinvertebrate densities or taxa richness as a function of environmental characteristics. They can be a tool for management purposes, providing the basis for habitat-based models and for the development of ecological indices.
Over the last years, bend-twist coupling (BTC) has become one of the most important passive load reduction techniques in wind turbine blades. The kind and amount of BTC is often decided on the basis ...of the load reduction, often forgetting the related stability implications. In this work we perform the stability analysis of a very large wind turbine, where the BTC is obtained by rotating the fibers of the spar caps. The study focuses first on the isolated blade, and then on the complete wind turbine. The findings show that this BTC leaves some modes unaffected, but reduces the damping of the collective edgewise mode.
Prosopis rubriflora and Prosopis ruscifolia are important species in the Chaquenian regions of Brazil. Because of the restriction and frequency of their physiognomy, they are excellent models for ...conservation genetics studies. The use of microsatellite markers (Simple Sequence Repeats, SSRs) has become increasingly important in recent years and has proven to be a powerful tool for both ecological and molecular studies.
In this study, we present the development and characterization of 10 new markers for P. rubriflora and 13 new markers for P. ruscifolia. The genotyping was performed using 40 P. rubriflora samples and 48 P. ruscifolia samples from the Chaquenian remnants in Brazil. The polymorphism information content (PIC) of the P. rubriflora markers ranged from 0.073 to 0.791, and no null alleles or deviation from Hardy-Weinberg equilibrium (HW) were detected. The PIC values for the P. ruscifolia markers ranged from 0.289 to 0.883, but a departure from HW and null alleles were detected for certain loci; however, this departure may have resulted from anthropic activities, such as the presence of livestock, which is very common in the remnant areas.
In this study, we describe novel SSR polymorphic markers that may be helpful in future genetic studies of P. rubriflora and P. ruscifolia.
Overland flow occurs on a land surface, making a sheet flow without any flow concentration. Under these conditions, cultivated semi-arid hillslopes experience inter-rill erosion. One objective of ...this study was to evaluate the hydraulic resistance caused by semi-arid crops and shrubs in two slopes' field conditions, and the other was to learen more about the overland flow governed by Froude number. To achieve these targets, a set of rainfall simulations was performed on two slope gradients, of 4.9% and 8.9%, covered by shrubs and semi-arid crops. On these two semi-arid hillslopes, exfiltration occurred, which added flow from subsurface water by seepage. We show, for the first time, that for overland flow with Reynolds number from 1 to 100 in different crops and native Brazilian shrub, hydraulic resistance is more strongly correlated with Froude number than with Reynolds number, as were the vegetal force drag and the soil detachment rate.
Purpose
In patients with type 1 diabetes (T1D), the prevalence of non-alcoholic fatty liver disease (NAFLD) ranges from 10 to 53% and contrasting evidence suggests that vitamin D deficiency may favor ...liver fat accumulation. Here, we investigated the association between vitamin D status and NAFLD in adults with T1D.
Methods
220 consecutive adult T1D patients on multiple daily injections or continuous subcutaneous insulin infusion and not taking calcium or vitamin D supplements were included. Patient characteristics, 25(OH)D serum levels, and metabolic parameters were analyzed. Vitamin D status was defined as sufficiency ( ≥ 75 nmol/L; 30 ng/ml), insufficiency (50–75 nmol/L; 20–30 ng/ml), or deficiency ( < 50 nmol/L; 20 ng/ml). NAFLD was diagnosed at ultrasound examination and graded 0–3.
Results
NAFLD was present in 57 patients (29.5%): 51 grade 1, 5 grade 2, and 1 grade 3. Median 25(OH)D levels were 53 nmol/L (IQR 38–70) in patients with NAFLD and 50 nmol/L (34–69) in patients without (
p
= 0.46). At multivariable analysis, NAFLD was not associated with 25(OH)D levels (
p
= 0.42) or vitamin D deficiency (
p
= 0.55), while BMI (OR 1.16, 95% CI 1.07–1.27) and serum triglycerides (OR 1.02, 95% CI 1.01–1.03) were independently associated with NAFLD.
Conclusions
Vitamin D status appears to have no link with low-grade NAFLD in patients with type 1 diabetes.
Bend-twist coupling behavior is induced in a blade by displacing the suction side spar cap towards the leading edge, and the pressure side one in the opposite direction. Additional couplings are ...introduced by rotating the spar cap fibers. The structural configuration of the blade is optimized using an automated design environment. The resulting blade shows significant benefits in terms of mass and loads when compared to the baseline uncoupled one. Finally, the lightweight design concept is used to increase the rotor size, resulting in a larger energy yield for the same hub loads.
The conservation of natural resources is the most important key for a sustainable agriculture, especially considering the decreasing conditional subsidies of the Common Agricultural Policy (CAP) of ...the European Union (EU) for the coming years: the lower economic supports oblige farms to increase efficiency to reduce production costs, whilst given the interaction of agricultural activities with environment quality, appropriate natural resources management will be a crucial aspect for farms.
The paper examines the efficiency of agricultural production systems and particularly the efficiency of energy use in a 3-yr soya bean, maize and wheat rotation. The study also aimed to analyse the production cost and the role of EU subsidies on farm strategies for important emerging management systems namely conservation farming (CF) and organic farming (OF) systems. Experiments were carried out in NE Italy, on a farm situated near Rovigo. Energy inputs were generally higher in the CF system but counterbalanced by a higher yield (output), while the OF system had generally reduced energy use (due to no chemical inputs) but lower yield. The economic net return was higher for the CF system, but when the economic subsidies from EU were considered, the integrated net return was higher in the OF system for soya bean and wheat.
This paper considers the problem of identifying the optimal combination of blade prebend, rotor cone angle and nacelle uptilt, within an integrated aero-structural design environment. Prebend is ...designed to reach maximum rotor area at rated conditions, while cone and uptilt are computed together with all other design variables to minimize the cost of energy. Constraints are added to the problem formulation in order to translate various design requirements. The proposed optimization approach is applied to a conceptual 10 MW offshore wind turbine, highlighting the benefits of an optimal combination of blade curvature, cone and uptilt angles.
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