341 research outputs found

    Probabilistic approaches for assessing rainfall thresholds triggering shallow landslides. The study case of the peri-vesuvian area (Southern Italy)

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    Ash-fall pyroclastic soil deposits covering steep carbonate slopes in the peri-Vesuvian area (southern Italy) are periodically involved in shallow landslides (about 700 events were recorded during the last three centuries, as reported by CASCINI et alii, 2008), triggered by intense and/or prolonged rainfall events, which evolve as catastrophic debris flows. In the last decades, many studies have been focused on estimating reliable relationships among the triggering of shallow landslides and the amount and duration of rainfall events, as well as the role played by antecedent soil hydrological conditions. Results of these studies have been expected to give information on temporal hazard to landslide onset to be used for setting a reliable early warning system. In this paper we present probabilistic approaches to assess rainfall thresholds triggering shallow landslides by classical empirical methods and to manage the uncertainties related to biases of data. At this scope, rainfall events related to the occurrence of debris flows along slopes of the Sarno and Lattari Mountains, known from chronicles of the last century, were analyzed by means of the empirical models of Intensity-Duration (I-D) (CAINE, 1980) and rainfall recorded in the day of the landslide occurrence (P) vs the antecedent cumulated rainfall (Pa) (CROZIER & EYLES, 1980). In order to limit and to assess uncertainties related to biases of rainfall data, a comparison with the regional probability model of high intensity rainfall, carried out in the framework of the VAPI Project (ROSSI & VILLANI, 1994) has been carried out. Moreover, rainfall data were processed by a bivariate logistic regression model resulting in the assessment of probability to landslide triggering, given an assumed rainfall event. The I-D empirical rainfall thresholds obtained by Caine model (1980) were compared to rainfall thresholds estimated by deterministic approaches (DE VITA et alii, 2013; NAPOLITANO et alii, 2016) showing a good match

    Fungal endophytes affect plant response to leaf litter with contrasting chemical traits

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    Abstract Plant litter decomposition is a crucial process of nutrient cycling within ecosystems. However, many studies have shown that, apart from its several beneficial effects, organic matter decomposition can be disadvantageous to seed germination, seedling growth, and physiological activity of plants. Litter decomposition was reported to affect both plants and their associated soil microbial communities. The aim of this work was to test the relationships between seed-associated endophytic fungi on the either positive or negative plant's response to different litter types. Leaf material of four species was collected and used in a decomposition experiment inside a growth chamber for 120 days. The plant growth experiment was set in a greenhouse using Trifolium repens and Triticum durum with and without their associated endophytic fungi in the presence of the different litter species at two decay levels (fresh litter and after 120 days of decomposition). Results demonstrated that fresh litter exerted a strong inhibition effect on the plant total biomass when compared to decomposed litter. Moreover, seed-associated endophytic fungi enhanced the inhibitory effect of litter in the observed experimental conditions. The removal of seed-associated endophytic fungi improved the capacity of tested plants to resist to litter inhibitory effect

    Contrast enhanced ultrasound (CEUS) in blunt abdominal trauma.

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    In the assessment of polytrauma patient, an accurate diagnostic study protocol with high sensitivity and specificity is necessary. Computed Tomography (CT) is the standard reference in the emergency for evaluating the patients with abdominal trauma. Ultrasonography (US) has a high sensitivity in detecting free fluid in the peritoneum, but it does not show as much sensitivity for traumatic parenchymal lesions. The use of Contrast-Enhanced Ultrasound (CEUS) improves the accuracy of the method in the diagnosis and assessment of the extent of parenchymal lesions. Although the CEUS is not feasible as a method of first level in the diagnosis and management of the polytrauma patient, it can be used in the follow-up of traumatic injuries of abdominal parenchymal organs (liver, spleen and kidneys), especially in young people or children

    Intravitreal triamcinolone, bevacizumab and pegaptanib for occult choroidal neovascularization.

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    PURPOSE: To evaluate best-corrected visual acuity (BCVA) and foveal thickness (FT) changes in occult subfoveal choroidal neovascularization (CNV) from age-related macular degeneration (AMD) after intravitreal bevacizumab (IVB, 1.25 mg/0.05 ml), pegaptanib (IVP, 0.3 mg/0.09 ml) and triamcinolone acetonide (IVTA, 4 mg/0.1 ml) injected on an as needed basis. METHODS:   Retrospective, interventional, comparative study. BCVA (Early Treatment Diabetic Retinopathy Study LogMAR) and FT by optical coherence tomography (OCT) were evaluated during 12 months from first treatment. Patients were retreated if signs of neovascular activity were still present on angiography or OCT. RESULTS: Forty-eight eyes received IVB, 43 eyes received IVP, 52 eyes received IVTA. BCVA and FT at baseline were 1.22 ± 0.49 LogMAR and 410.2 ± 41.83 μm in the IVB group, 1.25 ± 0.43 LogMAR and 452.3 ± 44.83 μm in the IVP group and 1.31 ± 0.4 LogMAR and 456.6 ± 48.27 μm in the IVTA group. BCVA and FT improved in the three groups during follow-up. A significantly greater improvement of BCVA was present at month-3, month-6 and at month-12 in the IVB and IVP groups (p = 0.01). Improvement of FT was greater in the IVTA group at month-3 (p = 0.02), while it was greater in the anti-Vascular Endothelial Growth Factor (VEGF) groups at month-6 and month-12 (p = 0.01). A postoperative increase of intraocular pressure was detected in 9/52 (17.3%) eyes treated with IVTA, and in two cases it was resistant to topical therapy. CONCLUSION:   Intravitreal injection of anti-VEGF drugs administered on an as needed basis for AMD-related occult CNVs provided functional and anatomic improvement during 12 months of follow-up

    Evaluation of salivary matrix metalloproteinase (MMP-8) in periodontal patients undergoing non-surgical periodontal therapy and mouthwash based on ozonated olive oil: A randomized clinical trial

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    Background: Extracellular matrix metalloproteinases (MMPs) play a pivotal role in the damage to the periodontal tissue in patients with periodontitis. Scaling and root planning (SRP) attempt to control the plaque amount and consequentially reduce the bacterial load. Non-surgical periodontal treatment could be integrated with drug therapy and physiotherapy procedures such as ozone therapy. The aim of this study was to evaluate in a cohort of patients with a diagnosis of periodontitis: (1) the efficacy of non-surgical periodontal therapy assisted by the use of ozonated olive oil-based mouthwash on salivary metalloproteinase (MMP-8) and (2) the reduction of periodontal indices. Methods: Ninety-six subjects with a diagnosis of periodontitis were enrolled in this study and randomly assigned to the study group (SRP + mouthwash) or control group (SRP). The study duration was 3 months. Data on MMP-8, plaque index (PI), bleeding on probing (BoP) and probing pocket depth (PPD) were recorded at T0, T1 (14 days), T2 (1 month) and T3 (6 months). Group differences were assessed using Student’s t-test for independent samples. Results: A significant improvement in PI, BoP, PPD and salivary MMP-8 levels was observed in both groups. An analysis of differences in relative changes of indices revealed the efficacy of ozonated olive oil in decreasing MMP-8 level. Simultaneously, it slowed the decrease of BoP index. Conclusions: Scaling and root plaining with the aid of ozonated olive oil mouthwash were found to be more effective on salivary MMP-8 reduction than scaling and root plaining alone

    Interacting effects of temperature, habitat and phenotype on predator avoidance behaviour in <i>Diadema antillarum</i>: implications for restorative conservation

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    Caribbean long-spined sea urchin Diadema antillarum populations crashed following a mass mortality event in 1983-1984 with cascading effects on reef health. Population restoration efforts may be hampered by unknown effects of short- and long-term elevated sea surface temperature (SST). We investigated how a key behavioural trait, predator avoidance behaviour (PAB; percentage of long defensive spines that moved in response to shadow stimuli), was affected by elevated SST in 180 individuals from 2 contrasting Honduran reefs: Utila (flattened reef structure, dearth of predation refugia) and Banco Capiro (complex reef structure, abundant refugia). Initiation of PAB is mediated by melanin, which breaks down at elevated water temperatures; thus, as SST rises, D. antillarum may become vulnerable to predation. We compared local current SST (CSST; 29.7°C) with 2 IPCC predicted long-term climate change scenarios under laboratory conditions. PAB decreased by 13.98-15.37% at CSST +1.4°C and 31.67-42.44% at CSST +3.1°C. Trial temperatures were similar to maxima recorded in the Caribbean during the 2016 El Niño, so our results also represent likely responses to worst-case short-term acute temperature anomalies. Juveniles maintained higher PAB than adults, indicating increased reliance on anti-predation behaviours. White-spined phenotypes from Utila’s flattened reef maintained higher PAB than black-spined counterparts, likely due to increased conspicuousness to visual predators. Habitat complexity may mitigate temperature-driven losses in natural behavioural defences. D. antillarum may be resilient to near-term (D. antillarum populations must be coupled to augmented reef complexity to improve future resilience

    Topography modulates near-ground microclimate in the Mediterranean Fagus sylvatica treeline

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    Understanding processes controlling forest dynamics has become particularly important in the context of ongoing climate change, which is altering the ecological fitness and resilience of species worldwide. However, whether forest communities would be threatened by projected macroclimate change or unaffected due to the controlling effect of local site conditions is still a matter for debate. After all, forest canopy buffer climate extremes and promote microclimatic conditions, which matters for functional plant response, and act as refugia for understory species in a changing climate. Yet precisely how microclimatic conditions change in response to climate warming will depend on the extent to which vegetation structure and local topography shape air and soil temperature. In this study, we posited that forest microclimatic buffering is sensitive to local topographic conditions and canopy cover, and using meteorological stations equipped with data-loggers we measured this effect during 1 year across a climate gradient (considering aspect as a surrogate of local topography) in a Mediterranean beech treeline growing in contrasting aspects in southern Italy. During the growing season, the below-canopy near-ground temperatures were, on average, 2.4 and 1.0 °C cooler than open-field temperatures for south and north-west aspects, respectively. Overall, the temperature offset became more negative (that is, lower under-canopy temperatures at the treeline) as the open-field temperature increased, and more positive (that is, higher under-canopy temperatures at the treeline) as the open-field temperature decreased. The buffering effect was particularly evident for the treeline on the south-facing slope, where cooling of near-ground temperature was as high as 8.6 °C for the maximum temperature (in August the offset peaked at 10 °C) and as high as 2.5 °C for the average temperature. In addition, compared to the south-facing slope, the northern site exhibited less decoupling from free-air environment conditions and low variability in microclimate trends that closely track the free-air biophysical environment. Although such a decoupling effect cannot wholly isolate forest climatic conditions from macroclimate regional variability in the south-facing treeline, it has the potential to partly offset the regional macroclimatic warming experienced in the forest understory due to anthropogenic climate change

    Stratigrafia ed assetto geometrico dell’Unità del Sannio nel settore settentrionale dei monti del Matese

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    New stratigraphic and biostratigraphic data arising from the realization of the Sheet No. 405 "Campobasso" of the new Geological map of Italy (1:50.000 scale - CARG Project) allowed, for the first time in this area, to stratigraphically and cartographically define all the ranges composing the basinal Sannio Unit Auct.. Structural analysis and the chronostratigraphic redefinition of siliciclastic deposits covering the Sannio Unit and the carbonate platform successions of the Matese- Frosolone Units, indicate two main evolutionary stages in the Miocene- Pliocene structuring of this portion of the Southern Apennines. In the first stage, starting before Serravallian times, E-verging contraction affected exclusively the basinal units together with their siliciclastic cover. During the second stage, beginning after early Messinian times, NE-verging compression involved both the basinal Sannio Unit and the Matese-Frosolone Units.UnpublishedISPRA - Roma, Italy2.2. Laboratorio di paleomagnetismorestricte

    Faster N release, but not C loss, from leaf litter of invasives compared to native species in mediterranean ecosystems

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    Plant invasions can have relevant impacts on biogeochemical cycles, whose extent, in Mediterranean ecosystems, have not yet been systematically assessed comparing litter carbon (C) and nitrogen (N) dynamics between invasive plants and native communities. We carried out a 1-year litterbag experiment in 4 different plant communities (grassland, sand dune, riparian and mixed forests) on 8 invasives and 24 autochthonous plant species, used as control. Plant litter was characterized for mass loss, N release, proximate lignin and litter chemistry by 13C CPMAS NMR. Native and invasive species showed significant differences in litter chemical traits, with invaders generally showing higher N concentration and lower lignin/N ratio. Mass loss data revealed no consistent differences between native and invasive species, although some woody and vine invaders showed exceptionally high decomposition rate. In contrast, N release rate from litter was faster for invasive plants compared to native species. N concentration, lignin content and relative abundance of methoxyl and N-alkyl C region from 13C CPMAS NMR spectra were the parameters that better explained mass loss and N mineralization rates. Our findings demonstrate that during litter decomposition invasive species litter has no different decomposition rates but greater N release rate compared to natives. Accordingly, invasives are expected to affect N cycle in Mediterranean plant communities, possibly promoting a shift of plant assemblages

    Different pathways but same result? Comparing chemistry and biological effects of burned and decomposed litter

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    Litter burning and biological decomposition are oxidative processes co-occurring in many terrestrial ecosystems, producing organic matter with different chemical properties and differently affecting plant growth and soil microbial activity. Here, we tested the chemical convergence hypothesis (i.e. materials with different initial chemistry tend to converge towards a common profile, with similar biological effects, as the oxidative process advances) for burning and decomposition. We compared the molecular composition of 63 organic materials - 7 litter types either fresh, decomposed for 30, 90, 180 days, or heated at 100, 200, 300, 400, 500 \ub0C - as assessed by 13C NMR. We used litter water extracts (5% dw) as treatments in bioassays on plant (Lepidium sativum) and fungal (Aspergillus niger) growth, and a washed quartz sand amended with litter materials (0.5 % dw) to assess heterotrophic respiration by CO2 flux chamber. We observed different molecular variations for materials either burning (i.e. a sharp increase of aromatic C and a decrease of most other fractions above 200 \ub0C) or decomposing (i.e. early increase of alkyl, methoxyl and N-alkyl C and decrease of O-alkyl and di-O-alkyl C fractions). Soil respiration and fungal growth progressively decreased with litter age and temperature. Plant growth underwent an inhibitory effect by untreated litter, more and less rapidly released over decomposing and burning materials, respectively. Correlation analysis between NMR and bioassay data showed that opposite responses for soil respiration and fungi, compared to plants, are related to essentially the same C molecular types. Our findings suggest a functional convergence of decomposed and burnt organic substrates, emerging from the balance between the bioavailability of labile C sources and the presence of recalcitrant and pyrogenic compounds, oppositely affecting different trophic levels
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