134,649 research outputs found
The relict landslide in bimsoils in downtown Genova, Italy: a new modeling approach
No full textStability problems occurring in geological units with a block-in-matrix fabric are often analyzed with deterministic approaches and/or assuming block-in-matrix rocks/soils (bimrocks or bimsoils) to be homogeneous equivalent geomaterials. However, recent studies have demonstrated that since these formations are characterized by a great (dimensional, spatial and lithological) variability, reliable results can only be obtained if a stochastic approach accounting for different block arrangements and dimensions is used.
This paper extends and improves a previous study from Minuto and Morandi (2015) to evaluate the stability of a relict landslide in bimsoil located in downtown Genova (Italy), where a deterministic approach and the traditional limit equilibrium method were used. In this work,
different slope models with elliptical blocks of variable eccentricity, size and positions are generated by means of a stochastic approach and are analyzed with the FEM code RS2. Moreover, since the slope can be considered to be a bimsoil, interfaces between the blocks and matrix are introduced in order to better simulate the lower strength at the block/matrix contacts.
The numerical analyses of the slope reveal that shallow failure surfaces have a higher probability
of occurrence as compared to the deep failure surfaces considered by Minuto and Morandi
(2015). Furthermore, lower safety factors are obtained when a block-matrix interface strength
smaller than that of the matrix (i.e., a bimsoil) is simulated
Techno-economic dataset for hydrogen storage-based microgrids
No full textThe challenge of energy storage is a pivotal consideration in renewable energy-based power systems. Hydrogen emerges as a highly promising alternative or complementary solution to electric batteries, showcasing its potential for long-term and high-capacity storage. In this context, energy system modeling and optimization has gained prominence as an indispensable research tool, aiding in the processes of designing, sizing, and managing the day-to-day operations of renewable energy systems integrated with a hydrogen storage unit. However, the gathering of reliable and accurate techno-economic data emerges as time-consuming tasks, and the lack of standardized reference data introduces variability in model results. This variability arises from inconsistent input parameters rather than the physics or complexity of energy systems, leading to potentially erroneous results and misguided policy recommendations. Recognizing the need for comprehensive and transparent datasets, we introduce this open data techno-economic repository. The dataset is meticulously designed to encompass key technologies essential for hydrogen production, compression, storage, and utilization within a power-to-power system. Specifically, techno-economic data are reported for electrolysers, fuel cells, battery energy storage systems, hydrogen compression units, and hydrogen storage vessels. The learning curves and cost functions embedded in this paper, delineating investment costs as a function of production scale up and size, are derived directly from the raw data, providing a nuanced understanding of the economic landscape
Acanthoprasium frutescens: un’endemica arroccata nel suo piccolo rifugio
No full textSono riportati i primi dati sull'osservazione dell'eventuale presenza di Nitidulidi su piante di Acanthoprasium frutescens in tutto il suo areale di distribuzione. Si suppone l'eventuale presenza di coleotteri predatori dei fiori che prò non sono mai stati ritrovati ne sottoforma di larve ne di adulti. Una analisi morfologica con latre Lamiaceae dimistra come A. frutescens sia dotato di importanti protezioni anatomiche contro l'attacco di fitofag
Jacobaea persoonii: il caso di un areale piccolo piccolo
No full textIn questo lavoro si è fatta verifica del reale areale di distibuzione della specie e viene effettuata una accurata descrizione dlle popolazioni certe della specie. Un confronto anatomico-morfologico mette in evidenza come la specie possa formare potenziali ibridi con una gogenerica simpatrica
The importance of stability throughout time in affecting the geographical pattern of endemism richness
No full textClimate change is one of the greatest threats to plant endemisms, particularly in mountain ecosystems that often show a high rate of endemism. Studies suggest that current centers of endemism are typically located in areas where the rugged mountainous topography buffered the effect of past climate changes and will probably buffer also the future changes.
To evaluate climatic stability we assessed shift in distribution of Köppen climatic types form last interglacial to present. Using species distribution models, we projected the climatic niche of 100 plant species endemic or subendemic to SW Alps (about 60% of all endemic and subebdemic species) in past (i.e., last interglacial, last glacial maximum and middle Holocene) and future (i.e., year 2070 using both an optimistic and a pessimistic scenario) climates.
We detected a higher current endemism richness (both potential and known) in areas climatically stable during the past than in not stable areas. We found a significant positive correlation between richness throughout past climates and both potential and known current endemism richness. Similarly, we found a significant positive correlation between future potential endemism richness and both past stability and current potential endemism richness. Nevertheless, endemic species in the SW Alps will experience high range loss (65.5% and 82.3% in the optimistic and pessimistic scenarios, respectively), not counterbalanced by range gain in adjacent areas because of low dispersal capabilities.
Our results suggest that, despite the ability of microrefugia to remain relatively stable and support high diversity in the future, absolute levels of endemism in the SW Alps will likely decline considerably, due to the inability of endemic species to disperse at a rate consistent with future climate change
Anisometry of space representation in neglect dyslexia
No full textPatients with unilateral neglect show disorders in horizontal space perception. It has been argued that these disorders may depend on a left-right relaxation of the representational medium that becomes progressively "relaxed" toward the contralesional space and progressively "compressed" toward the ipsilesional space. We tested this hypothesis in 31 right-brain-damaged patients, 17 with neglect and 14 without neglect in two different experiments. Patients were asked to read words in canonical and anisometric letter spacing. Only in neglect patients, the manipulation of letters spacing may ameliorate neglect dyslexia. These results support the idea that the abnormalities observed in typical neglect tests are due to a distorted internal representation of the outside world. In addition, the space distortion seems to depend on the degree of horizontal relaxation of the representational medium and it is unrelated to hemianopia
Dynamic modeling and thermal management of a Power-to-Power system with hydrogen storage in microporous adsorbent materials
No full textThe increasing penetration of distributed renewable energy sources involves the development of efficient energy storage solutions. Hydrogen is a viable alternative, or complement, to electric batteries for long-term and high-capacity storage. This article assesses the benefits of hydrogen storage in microporous adsorption materials at room temperature. The integrated Power-to-Power system dynamic behavior is modelled. We assessed the system performance looking at hydrogen adsorption in four porous materials (MSC-30, IRMOF-1, NU-110, and C/Be2) at room temperature for high-storage capacity. Hydrogen storage in an empty pressurized vessel by means of mechanical compression only is evaluated for comparison of the previous cases. The best performance in terms of tank volume size and round-trip efficiency are obtained by adopting adsorbent materials as follows: C/Be2 > IRMOF-1 > NU-110 > MSC-30 > empty storage. Indeed, under the same operating conditions, the volume size of the storage tank is reduced by 38 to 88% compared to the empty vessel, and the round-trip efficiency gain ranges between 0.6 and 2.8 percentage points according to the properties of the adsorbent material. Finally, by filling the storage tank with adsorbent materials the DOE targets are met at a pressure from 45% (MSC-30) to 83% (C/Be2) lower than in an empty tank
Divergence is not enough: the use of ecological niche models for the validation of taxon boundaries
No full textDelimiting taxon boundaries is crucial for any evolutionary research and conservation
regulation. In order to avoid mistaken description of species, the approach of integrative
taxonomy recommends considering multidisciplinary lines of evidence, including
ecology. Unfortunately, ecological data are often difficult to quantify objectively. Here
we test and discuss the potential use of ecological niche models for validating taxon
boundaries, using three pairs of closely related plant taxa endemic to the south-western
Alps as a case study. We also discuss the application of ecological niche models
for species delimitation and the implementation of different approaches.
• Niche overlap, niche equivalency and niche similarity were assessed both in multidimensional
environmental space and in geographic space to look for differences in the
niche of three pairs of closely related plant taxa.
• We detected a high degree of niche differentiation between taxa although this result
seems not due to differences in habitat selection. The different statistical tests gave
contrasting outcomes between environmental and geographic spaces.
• According to our results, niche divergence does not seem to support taxon boundaries
at species level, but may have had important consequences for local adaptation and in
generating phenotypic diversity at intraspecific level. Environmental space analysis
should be preferred to geographic space as it provides more clear results. Even if the
different analyses widely disagree in their conclusions about taxon boundaries, our
study suggests that ecological niche models may help taxonomists to reach a decision
Between past and future: legacy and fate of an important centre of endemism for the Mediterranean region
No full textClimate change is one of the greatest threats to biodiversity, particularly in mountain ecosystems, which
often show high endemism rate. Studies on past climate changes suggested that current centers of endemism
are placed where climatic fluctuations were less pronounced (because of mountainous topography) and that
these areas will be less affected by climate change in the future (1). However, this doesn’t mean that these
areas will not experience drastic climate change effects; in fact, several evidences indicate that mountain
endemics are disproportionally exposed to climate change, because usually they are characterized by small
range size, narrow ecological tolerance and poor dispersal ability (2).
SW Alps are one the most important centers of endemism of the Mediterranean Basin and are particularly
exposed to climate change threat due to the contemporaneous effects of temperature increase and
precipitation decrease, as other Southern European mountain systems (3). Taking into account dispersal
abilities, we used Species Distribution Models to analyze the distribution of suitable climatic conditions for
100 plant species endemic or subendemic of SW Alps (about 60% of endemisms of this area). We projected
predicted suitability in past (i.e.: last interglacial, last glacial maximum, middle Holocene), current and
future (i.e: year 2070) time slices. For each time slice we elaborate a map of potential species richness; for
each species we also calculated the percentage of range loss and gain in the future, considering both
optimistic and pessimistic emission scenarios
Niche divergence between putative taxa: ecological niche models in taxonomic researches
No full textFor over a century, species delimitation was a critical task for biologists, concerning both species concept
and operational methods necessary for the individuation of taxa boundaries. According to the recent
approach of integrative taxonomy, species have to be considered as hypotheses that should be tested with
different methods. Ecological interchangeability can be an element that can corroborate the separation of two
putative taxa, but ecological data are often difficult to use. Ecological Niche Models (ENMs) provide a
quantification of niche parameters and could be a useful tool for investigating taxa boundaries. For this
purpose, we used ENMs for testing ecological (climatic) differentiation in three pairs of related taxa recently
subdued to taxonomical revisions without explicitly considering ecological evidences.
The selected taxa pairs are: Rhaponticum bicknellii (Briq.) Banfi, Galasso & Soldano and R. heleniifolium
Godr. & Gren.; Gentiana burseri subsp. actinocalyx Polidori and Gentiana burseri subsp. villarsii (Griseb.)
Rouy Fritillaria tubaeformis Gren. & Godr. subsp. moggridgei (Baker) Rix and Fritillaria tubaeformis
subsp. tubaeformis. For each pair, we assessed niche overlap, niche equivalency and niche similarity in both
multidimensional environmental space (E-space) and geographical space (G-space)
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