1,266 research outputs found
Integrated use of local and technical soil quality indicators and participatory techniques to select them. A review of bib-liography and analysis of research strategies and outcomes
Climate change has strong impacts on soil conservation and agricultural productivity, with severe consequences on smallholders in developing countries, but virtually no research has been carried out so far on this issue. Therefore, it is necessary to foster the implementation of participatory projects to help communities deal with new difficulties. Sustainable soil management can reduce and even reverse land degradation, helping farmers to adapt to climate change effects. Pro-gress toward sustainability cannot be implemented in small rural communities regardless of local knowledge, which can be addressed using participatory techniques. To this purpose the choice and use of indicators is essential to carry out correct assessments of soil vulnerability integrating local and technical knowledge. The purpose of this review was to study how the problem of building a set of integrated indicators to assess soil quality has been addressed so far and which participatory techniques have been more successfully employed, analyzing studies carried out in rural communities of developing countries. We found out that there is a lack of participated studies dealing with environmental issues. Those that do so address them only indirectly, being centered on present agricultural problems. The studies rarely feature a collaboration with social science experts, consequently the use of participatory techniques lacks protocols and a standardized nomenclature to help in the transfer and generalization of experiences. Women are rarely involved and nearly exclusively in African countries: this could be related to social and cultural conditions, but needs more atten-tion. Different aspects need to be improved to help the implementation of a successful approach in future projects. This review provides a tool to facilitate future interdisciplinary research on integration of local and scientific knowledge and will help to devise more successful strategies to tackle the challenges posed by climate change to smallholders in developing countries
Temperature changes and the ATP concentration of the soil microbial biomass
Two soils from temperate sites (UK; arable and grassland) were incubated aerobically at 0, 5, 15 or 258C for up to 23 days.
During this period both soils were analysed for soil microbial biomass carbon (biomass C) and adenosine 5' triphosphate
contents (ATP). Biomass C did not change signi\uaecantly in either soil at any temperature throughout, except during days 0 to 1
in the grassland soil. Soil ATP contents increased slowly throughout the 23 days of incubation, from 2.2 to a maximum of 3.1
nmol ATP g
\uff1 soil in the arable soil (a 40% increase) and from 6.2 to a maximum of 11.2 nmol ATP g
\uff1 soil in the grassland
soil (an increase of 81%), both at 258C. Since biomass C did not change either with increasing temperature or increasing time of
incubation, it was concluded that an increase in ATP was either due to an increase in adenylate energy charge or de novo
synthesis of ATP, or both. During the incubation, biomass ATP concentrations ranged from about 5 to 12 mmol ATP g
\uff1
biomass C but trends between biomass ATP and incubation temperatures were not very obvious until about day 13. On day 23,
biomass ATP concentrations were positively and linearly related to temperature: (mmol ATP g
\uff1 biomass C = 6.9820.35 +
0.13420.023 T0 (r 2 = 0.77) with no signi\uaecant di erence in the slope between the grassland and arable soils. At 258C the
biomass ATP concentration was 10.3 mmol g
\uff1 biomass C, remarkably close to many other published values. It was concluded
that, although the biomass increased its ATP concentration in response to increasing temperature, the increase was
comparatively small. Also, at all temperatures tested, the biomass maintained its ATP concentration within the range commonly
reported for micro-organisms growing expontentially in vitro. This is despite the fact that the biomass normally exhibits other
features more typical of a ``resting'' or dormant population
0 a paradox which still is not resolved
Antioxidant properties of humic acids extracted from saltmarsh soils (Marano and Grado Lagoon, northern Adriatic Sea)
Bioaccumulation of polycyclic aromatic hydrocarbons and survival of earthworms (Eisenia andrei) exposed to biochar amended soils
Biochar has a charcoal polycyclic aromatic structure which allows its long half-life in soil, making it an ideal tool for C sequestration and for adsorption of organic pollutants, but at the same time raises concerns about possible adverse impacts on soil biota. Two biochars were tested under laboratory-controlled conditions on Eisenia andrei earthworms: a biochar produced at low temperature from wine tree cuttings (WTB) and a commercial low tar hardwood lump charcoal (HLB). The avoidance test (48-h exposure) showed that earthworms avoid biochar-treated soil with rates higher than 16 t ha 121 for HLB and 64 t ha 121 for WTB. After 42 days, toxic effects on earthworms were observed even at application rates (100 t ha 121) that are generally considered beneficial for most crops. The concentration of HLB and WTB required to kill half of earthworms\u2019 population (LC50; 95 % confidence limits) in the synthetic OECD soil was 338 and 580 t ha 121, respectively. Accumulation of polycyclic aromatic hydrocarbons (PAH) in earthworms exposed to the two biochar types at 100 t ha 121 was tested in two soils of different texture. In biochar-treated soils, the average earthworm survival rates were about 64 % in the sandy and 78 % clay-loam soils. PAH accumulation was larger in the sandy soil and largest in soils amended with HLB. PAH with less than four rings were preferentially scavenged from the soil by biochars, and this behaviour may mask that of the more dangerous components (i.e. four to five rings), which are preferentially accumulated. Earthworms can accumulate PAH as a consequence of exposure to biochar-treated soils and transfer them along the food chain. Soil type and biochar quality are both relevant in determining PAH transfer
Characterization of humic fractions in leachates from soil under organic and conventional management and their interactions with the root zone
Humic fractions were shown to be closely involved in gene expression
and promotion of different PM H+-ATPase isoforms, as well as in lateral root
development, indicating an enhanced nutrient absorption capacity of the plant
root system. HPLC-SEC confirmed that water-soluble humic substances (WSHS)
correspond to a subfraction of the fulvic fraction of humic substances. This was
supported by E465/E665 ratios higher than 8.5. These ratios generally increased over
the growing season in cultivated soils but showed significant differences between
conventionally and organically managed bare soils. FTIR data and the analytical
quantification of carboxyls confirmed relevant structural changes in bare soil under
both organic and conventional farming management. Absorption intensities ratios
at 1,590–1,570 cm-1 and 1,440–1,380 cm-1 showed the predominant aliphatic
character of these molecules
The complexity of soil biological sustainability
Additions of organic amendments to soil not only compensate for decreased soil
C, but also contribute to energy requirements for conserving biological activity levels.
The soil microbial biomass displays some highly conserved, and possibly unique,
characteristics that do not permit a classic interpretation of microbial metabolic
parameter data. The resilience of soil microbial biomass and the role of soil organic
matter in sustaining microbial biomass under practically zero C inputs were assessed
in two long term incubation experiments using soils from the Broadbalk experiment
at Rothamsted (UK). Soils with low organic C contents, showed the greatest decline in
biomass C during the first 30 d of incubation. The ATP concentration of this rapidly
declining microbial biomass did not change during the prolonged incubation period,
confirming this peculiar character of the soil microbial biomass. Specific respiration
rate did not depend upon substrate availability, being higher in soils that had received
the lowest C inputs. Qualitative and quantitative changes observed in humic fractions
suggest that humified soil organic matter is a much more dynamic soil fraction than is
normally considered and provides a utilizable energy reserve for soil microorganisms.
Carbon levels can be successfully restored in soils through practices such as
incorporation of crop residues, re\u2010vegetation and application of manures, biosolids
and composts. Some amendments, such as olive mill waste compost, promote
incorporation of altered lignin structures, N\u2010containing compounds and
carbohydrates into humic acids. The mineral\u2010bound fraction of humic C also increases,
after their addition, and contributes to the accumulation of the most inert soil C pools
Characterization of humic fractions in leachates from soil under organic and conventional management and their interactions with the root zone
Humic fractions were shown to be closely involved in gene expression
and promotion of different PM H+-ATPase isoforms, as well as in lateral root
development, indicating an enhanced nutrient absorption capacity of the plant
root system. HPLC-SEC confirmed that water-soluble humic substances (WSHS)
correspond to a subfraction of the fulvic fraction of humic substances. This was
supported by E465/E665 ratios higher than 8.5. These ratios generally increased over
the growing season in cultivated soils but showed significant differences between
conventionally and organically managed bare soils. FTIR data and the analytical
quantification of carboxyls confirmed relevant structural changes in bare soil under
both organic and conventional farming management. Absorption intensities ratios
at 1,590\u20131,570 cm-1 and 1,440\u20131,380 cm-1 showed the predominant aliphatic
character of these molecules
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Lipid-induced hepatocyte-derived extracellular vesicles regulate hepatic stellate cell via microRNAs targeting PPAR-γ.
Background&aimsHepatic stellate cells (HSCs) play a key role in liver fibrosis in various chronic liver disorders including nonalcoholic fatty liver disease (NAFLD). The development of liver fibrosis requires a phenotypic switch from quiescent to activated HSCs. The triggers for HSCs activation in NAFLD remain poorly understood. We investigated the role and molecular mechanism of extracellular vesicles (EVs) released by hepatocytes during lipotoxicity in modulation of HSC phenotype.MethodsEVs were isolated from fat-laden hepatocytes by differential centrifugation and incubated with HSCs. EV internalization and HSCs activation, migration and proliferation were assessed. Loss- and gain-of-functions studies were performed to explore the potential role of PPAR-γ-targeting miRNAs carried by EVs into HSC.ResultsHepatocyte-derived EVs released during lipotoxicity are efficiently internalized by HSCs resulting in their activation, as shown by marked up-regulation of pro-fibrogenic genes (Collagen-I, α-SMA and TIMP-2), proliferation, chemotaxis and wound healing responses. These changes were associated with miRNAs shuttled by EVs and suppression of PPAR-γ expression in HSC. Hepatocyte-derived EVs miRNA content included various miRNAs that are known inhibitors of PPAR-γ expression with miR-128-3p being the most effectively transferred. Furthermore loss- and gain-of-function studies identified miR-128-3p as a central modulator of the effects of EVs on PPAR-γ inhibition and HSC activation.ConclusionOur findings demonstrate a link between fat-laden hepatocyte-derived EVs and liver fibrosis and have potential implications for the development of novel anti-fibrotic targets for NAFLD and other fibrotic diseases
Paediatric non-alcoholic fatty liver disease: impact on patients and mothers' quality of life
Background: Non-alcoholic fatty liver disease (NAFLD) is one of the causes of fatty liver in adults and is currently the primary form of chronic liver disease in children and adolescents. However, the psychological outcome (i.e. the behavioural problems that can in turn be related to psychiatric conditions, like anxiety and mood disorders, or lower quality of life) in children and adolescents suffering of NAFLD has not been extensively explored in the literature. Objectives: The present study aims at evaluating the emotional and behavioural profile in children suffering from NAFLD and the quality of life in their mothers. Patients and Methods: A total of 57 children (18 females/39 males) with NAFLD were compared to 39 age-matched control children (25 females/14 males). All participants were submitted to the following psychological tools to assess behavior, mood, and anxiety: the Multidimensional Anxiety Scale for Children (MASC), the Child Behavior Checklist (CBCL), and the Children's Depression Inventory (CDI). Moreover, the mothers of 40 NAFLD and 39 control children completed the World Health Organization Quality of Life-BREF (WHOQOL-BREF) questionnaire. Results: NAFLD children scored significantly higher as compared to control children in MASC (P = 0.001) and CDI total (P < 0.001) scales. The CBCL also revealed significantly higher scores for NAFLD children in total problems (P = 0.046), internalizing symptoms (P = 0.000) and somatic complaints (P < 0.001). The WHOQOL-BREF revealed significantly lower scores for the mothers of NAFLD children in the overall perception of the quality of life (P < 0.001), and in the "relationships" domain (P = 0.023). Conclusions: Increased emotional and behavioural problems were detected in children with NAFLD as compared to healthy control children, together with an overall decrease in their mothers' quality of life. These results support the idea that these patients may benefit from a psychological intervention, ideally involving both children and parents, whose quality of life is likely negatively affected by this disease
Preliminary Design and Numerical Analysis of a Scrap Tires Pyrolysis System
Abstract A plant prototype for whole scrap tires disposal and the consequent syngas production via pyrolysis has been developed. A numerical analysis on the innovative pyrolysis reactor, constituted by an autoclave closing device and an explosion-proof water system has been carried out. The aim of this analysis is to investigate the fluid-dynamics in the pyrolysis chamber and model the syngas production. The simulations, performed in the pre-realization system phase, have allowed to determine: i) the flow field of the fluid within the reactor, so as to optimize the geometry (e.g. size, vacuum system, water tank); ii) the temperature range, in order to determine the correct placement of thermocouples within reactor and prevent overheating that could compromise the safety of the system; iii) the pressure range, necessary to avoid the eventual flooding of the tires themselves. Thanks to these results, the test bench has been built at the CURTI S.p.A laboratory and experimental analysis has been performed. The experimental data are acquired and then elaborated, as shown in the paper
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