Local Scarcity Research Articles

Quantifying the informal sand market and its consequences: The case of Brazil

Sand is a globally abundant resource and one of the most used minerals in construction. Local scarcity is becoming more common owing to the increasing demand in urban areas and stricter environmental regulations. In addition, the environmental impact caused by sand mining is worsened by clandestine extraction, which operates in a predatory manner. To reach the targets proposed by the United Nations Sustainable Development Goals, a country needs to combat the illegal extraction of sand, and this is only possible by knowing the local situation that needs to be changed. This study aims to estimate more accurately the total sand consumption that is being illegally extracted and is used by the Brazilian construction sector, its consequences, and ways to mitigate it. The method is applicable to any country with a similar problem. The results show that 76% of the extracted sand in Brazil is being mined illegally. The sum of unspent funds in environmental recovery, annual uncollected taxes, and annual unpaid social charges due to the activities of unregulated mining companies were equivalent to USD 774 million (0.05% of Brazil's GDP) in 2020. Strategies for concrete and mortar industrialization, and the substitution of natural sand by secondary materials could mitigate half of the illegal sand market that supplies sand for Brazilian construction, but it requires efforts of the entire construction sector, society, and government.

Investigation of the Impact of Chloride Contamination on Degradation in PEM Water Electrolyzer Cells

Polymer electrolyte membrane water electrolysis (PEMWE) is a promising technology for hydrogen production from renewable energy sources. However, current systems require ultra-pure water (>18 MΩ*cm) and fail in the presence of impurities like dissolved ions or chemical contaminants [1,2]. Due to the cost of purification and local scarcity of groundwater, there is a rising interest in creating electrolyzers that can function using water of inferior quality [3]. Additionally, feedwater used in offshore applications that is generated by the desalination of seawater still contains low amounts of ionic contaminants [4].Among the most detrimental impurities responsible for performance loss in PEMWE, Cl− is present in high concentrations in both, sea- and potable water [3]. Cl− can reduce the efficiency of the electrolysis process by accelerating component degradation and lower the purity of the produced hydrogen. A competing reaction between the oxygen evolution reaction (OER) and the chlorine evolution reaction (CER) results in the formation of gaseous chlorine that lowers the quality of the produced hydrogen gas. Additionally, Cl− blocking layers can form on the catalyst surfaces which result in a reduced electrochemical surface area. For PEM fuel cells, a technology facing related problems, Cl− adsorption has also been reported to accelerate the formation of hydrogen peroxide [5], promoting chemical degradation of the PFSA-based membrane.The scope of this work is to quantify the reduction of efficiency based on different Cl− concentrations in the feedwater of a PEMWE cell. Therefore, a single cell PEMWE with commercial catalyst coated membranes (CCMs) is exposed to different concentrations of Cl−. The PEMWE single cell is operated up to 100 h and investigated by various characterization techniques, including in-situ and ex-situ cell tests. Electrochemical performance characterization by means of polarization behaviour and impedance spectroscopy is carried out throughout a range of currents (0.01 A cm− 2 to 3.0 A cm− 2) at 60°C. Furthermore, the fluoride emission rate (FER) is monitored during the experiments and optical investigation of the CCMs is carried out after the tests. Based on this complementary investigation, a deeper insight into degradation phenomena associated with Cl− contamination in PEMWE cells is presented. Feng, Q.; Yuan, X.; Liu, G.; Wei, B.; Zhang, Z.; Li, H.; Wang, H. A Review of Proton Exchange Membrane Water Electrolysis on Degradation Mechanisms and Mitigation Strategies. Journal of Power Sources 2017, 366, 33–55, doi:10.1016/j.jpowsour.2017.09.006.Kuhnert, E.; Hacker, V.; Bodner, M. A Review of Accelerated Stress Tests for Enhancing MEA Durability in PEM Water Electrolysis Cells. International Journal of Energy Research 2023, 2023, 1–23, doi:10.1155/2023/3183108.Becker, H.; Murawski, J.; Shinde, D.V.; Stephens, I.E.L.; Hinds, G.; Smith, G. Impact of Impurities on Water Electrolysis: A Review. Sustainable Energy Fuels 2023, 7, 1565–1603, doi:10.1039/D2SE01517J.Bacquart, T.; Moore, N.; Wilmot, R.; Bartlett, S.; Morris, A.S.O.; Olden, J.; Becker, H.; Aarhaug, T.A.; Germe, S.; Riot, P.; et al. Hydrogen for Maritime Application—Quality of Hydrogen Generated Onboard Ship by Electrolysis of Purified Seawater. Processes 2021, 9, 1252, doi:10.3390/pr9071252.Katsounaros, I.; Meier, J.C.; Mayrhofer, K.J.J. The Impact of Chloride Ions and the Catalyst Loading on the Reduction of H2O2 on High-Surface-Area Platinum Catalysts. Electrochimica Acta 2013, 110, 790–795, doi:10.1016/j.electacta.2013.03.156.

Street-scale dispersion modelling framework of road-traffic derived air pollution in Hanoi, Vietnam

Traffic is an important source of air pollution in Vietnamese cities. The spatio-temporal variation of air pollution derived from traffic is poorly understood. Application of dispersion modelling can help but is hindered by the local scarcity of suitable input data. This study fills the data gap, by establishing a framework employing open-access global data to model emission from traffic activities in Hanoi. The outlined methodology explicitly defines road sources, calculates their emission, and employs background pollution profiles from Copernicus Atmospheric Monitoring Service (CAMS) to produce street-scale distribution maps for CO, PM10 and PM2.5. Pollution hotspots are found near major traffic flows with the highest hourly average CO, PM10 and PM2.5 concentrations at 1206, 87.5 and 61.5 μgm−3, respectively. The relationship between concentrations and properties of the road network is assessed. Motorcycles are the main emitters of the traffic sector. Emission from Heavy Good Vehicles dominate during the night, with contribution percentages increase as it gets further away from the city core. Modelled concentrations are underestimated mainly due to low vehicular emission factor. Adjusting emission factors according to vehicle quality in Vietnam greatly improves agreement. The presence of non-traffic emission sources contributes to the model underestimation. Results for comparisons of daily averaged PM values are broadly in agreement between models and observations; however, diurnal patters are skewed. This results partly from the uncertainties linked with background pollution levels from CAMS, and partly from non-traffic sources which are not accounted for here. Further work is needed to assess the use of CAMS's concentrations in Vietnam. Meteorological input contributes to the temporal disagreement between the model and observations. The impact is most noticeable with CO concentrations during morning traffic rush hours. This study recommends approaches to improve input for future model iterations and encourage applications of dispersion modelling studies in similar economic settings.

Climate Change, Security, and the International System: It’s Still the Same Old Story

Climate Change, Security, and the International System: It’s Still the Same Old Story

Circularity of water - good for conscience or the environment? A deeper look into the water footprint of factories.

Water plays an indispensable role in factories and is needed for a diversity of purposes. The circular use of water is an often-found approach nowadays which refers to the multiple internal recycling of water in factories before releasing it back to the environment. The intention behind that is clear and good – but the question is whether this is actually beneficial from an environmental perspective? This paper aims at providing a more detailed look into that important topic while analyzing efforts and benefits of water circularity. A generic life cycle assessment (LCA) model is presented and different industrial related scenarios serve as a base for deriving deeper and transferable insights into environmentally sustainable water management in factories. For the target objective water consumption, the recycling rate is of limited relevance as it only influences water use (withdrawal) but not the decisive evaporation rate. In a similar way, freshwater deprivation impacts resulting from water consumption (evaporation) depend on the location of the factory and the local scarcity – but not on recycling rates. Also for the global warming potential (GWP), the recycling rate is of limited relevance, as waste water treatment (WWT) is the decisive factor here. In cases in which the internal WWT causes more environmental efforts than municipal WWT and in which a relevant share of water is withdrawn from groundwater, an increasing recycling rate can reduce the depletion of groundwater resources – but causes higher carbon emissions. Depending on local scarcity and carbon intensity of electricity mixes, this can be justified but trade-offs need to be considered.

Deer Exclusion Regenerates Native Plant Functional Responses, but Not Species Richness in an Eastern Serpentine Savannah

Plants are particularly vulnerable to physical disturbance in low productivity areas, due to the high energetic cost of replacing lost tissue. In the eastern United States, serpentine savannahs are fragmented ecosystems with high concentrations of rare endemic plant species, low concentrations of soil nutrients, and severe deer overpopulation. This study assessed the recovery of flowering plants in a serpentine savannah when deer were excluded. Plant count, flower count, vegetative area, and plant height of 10 serpentine plant species were compared inside and outside of deer exclusion structures throughout an entire growing season. Throughout the growing season and across the plant community, deer exclusion consistently increased values for all plant response traits measured. Species that responded most strongly to deer exclusion included Arabis lyrata (Brassicaceae, the wide ranging lyre-leaf rockcress) and the serpentine near-endemic Symphyotrichum depauperatum (a serpentine aster known only in the eastern US). The slender knotweed, Polygonum tenue performed worse in excluded areas, which may indicate exclusion by more competitive species, or, alternatively, local scarcity. Overall, species richness did not increase in excluded plots, which may indicate that years of deer overbrowsing have depleted the local seed banks. While longer term studies might reveal different results, this study showed significant differences in vegetation response traits between excluded and unexcluded areas in just one year. We recommend that further restoration efforts should include reintroductions of locally extirpated species, in combination with deer exclusion to allow rare serpentine plant communities and their seedbanks to recover from intense overbrowsing pressure.

Water Sources Inventory, Annotated Checklist, and Distribution of Water Sources Under Gelephu, Samtenling, and Dekiling Gewog in Sarpang District, Bhutan

The Kingdom of Bhutan is endowed with abundant water resources. However, owing to rugged topography and associated climatic variations, accessibility remains a major challenge with communities facing seasonal and local scarcity of water. Generally, freshwater appears in the form of glaciers, lakes, wetlands, marshes, springs, and streams which support diverse life and livelihood. However, comprehensive inventories of water resources seem lacking in a water-rich country like Bhutan. Thus, water sources inventory was carried out using Focus Group Discussion and semi-structured questionnaires survey with 81 households (27 villages) from three highly populated gewog under Sarpang district in 2016 and collected the geo-coordinates (location) of each water source using Garmin GPS. The survey recorded a total of 104 perennial water sources from three gewogs under the district. Among the three gewogs, Samtenling and Dekiling have the highest water sources (n = 40) and Gelephu has the lowest (n = 24). While, in the case of source types, Samtenling gewog has the highest (n = 29), followed by Gelephu (n = 18) and Dekiling has the lowest (n = 14). Likewise, Dekiling has the highest number of streams (n = 24), followed by Samtenling (n = 9) and the lowest was Gelephu (n = 6). Therefore, periodic monitor of existing water sources, strengthening water governance, and adaptation of an integrated watershed management plan backed with detailed hydro-geological assessment covering entire watersheds are suggested for ensuring sustainable management of water sources, but also mitigates the climate change effects of these regions in the future.

Impacto do transporte nas emissões de CO2 do concreto: um estudo de caso em Rio Branco/Brasil

Abstract Due to the scarcity of crystalline massifs in the north of Brazil, concrete producers have been using crushed stone and cement from suppliers located hundreds of kilometers away. In this case, CO2 emissions related to material transportation for concrete production may become significant. Thus, this study aims to analyze the influence of the transportation of the materials in CO2 emissions of ready-mix concrete production in Rio Branco (Acre). Concrete compositions were obtained from a local concrete producer. Brazilian methods of dosage were not applicable due to the high fineness of the regional sand available; the mix designs were adjusted empirically. Two types of cement (CP V-ARI and CP IV) were considered to create the studied scenarios. Transportation distances of the raw materials (cement and aggregates) ranged from 20 km (local sand supplier) to 3,592 km (cement supplier from Sete Lagoas, MG). CO2 emissions to produce concrete (fck of 25 MPa, cement consumption of 426 kg/m3) ranged from 208 kgCO2/m3 to 573 kgCO2/m3. Transportation was responsible for up to 20% of total emissions. The emissions in this study are considerably higher than the national data of concrete production available in the Construction Environmental Performance Information System (Sidac) due to the higher cement consumption and higher transportation distances. Although cement consumption in Acre represents less than 1% of Brazilian consumption, the results reveal the impact of transportation distances in CO2 emissions of concrete in cities that deal with local scarcity.

Design and experimental Analyses of enhanced heat transfer performance in solar powered Injera baking pan using Cu/Oil and A12O2/Oil nanofluids

There are demands for wood in high populated areas in Ethiopia due to the fact that many people used wood, residue of crop, animal dung (dried) as fuel for cooking. This has led to ecological damage and local scarcity in these areas. Most people in Ethiopia use local baking pan to prepare their food like Injera. This local baking pan has drawbacks like low efficiency due to the poor thermal efficiency. Using wood as the primary source for the baking pan also has negative health, economy and environmental impact like deforestation. This has also led to smoke (indoor) pollution which affects the health of the most vulnerable like women and children. This research is aimed at investigating the performance enhancement of Injera baking oven powered by solar energy by using copper-oil and aluminium oxide-oil nanoparticles. Solar collector (parabolic) via trough assembly, baking pan assembly, the pump, reservoir of thermal fluid, working fluid reservoir (cold temperature), and connecting pipes made the system. Copper-oil and aluminium-oil were used as fluids for heat transfer. These fluids have diameters of 30–50 nm.At volume concentration of 0.3%, the solar collector efficiency for copper-oil was above 60% approximately which is the highest value. This is followed by the aluminium oxide-oil with efficiency of approximately 56% while the ordinary oil showed efficiency of 48%. The average thermal efficiency for copper-oil was 43% while that of aluminium oxide-oil was 39%. The ordinary oil stood at 35% average thermal efficiency. The copper-oil as a working fluid performed better than that of aluminium oxide-oil at 0.3% volume concentration. Likewise, at the volume concentration of 0.05%, the average thermal efficiency for copper-oil was 39% while that of aluminium oxide-oil was 35.1%. Ordinary oil stood at 34.9% at 0.05% volume variation. Copper-oil as a working fluid performed better than other working fluids at volume concentration of 0.05%

Changes in Wood Utilization Due to Iron Age Jade Mining in the Western Hexi Corridor: Wood Charcoal Investigations

Charcoal remains from archeological sites are used not only to reconstruct the historical composition of local woodlands but also to examine the history of the human use of wood. Nevertheless, key questions such as how and why people may have selected particular woody taxa from locations long distances from their habitat have rarely been addressed. In the present study, we analyze charcoal remains from the ancient Jingbaoer (JBR) jade mine in the Mazong Mountains (Mazong Shan) of Northwest China to explore patterns in the collection and use of wood by Iron Age people. Factors affecting the choice of wood collected at the JBR site are discussed by combining the results of pollen records and charcoal analysis. Our results suggest that tamarisk (Tamarix L.), a shrub dominant in the local area, was the main source of wood for JBR miners and was used as firewood depending upon its local availability. The miners may also have used wood from species sourced further away, such as Pinus L. and Picea L., because of the local scarcity of these trees in such a dry environment. The agropastoralist subsistence system practiced by the JBR miners supports the hypothesis of the collection of wood from distant locales. This study highlights diverse patterns of wood collection in an area scarce in woody plants and provides new evidence for understanding how Iron Age people adapted to extremely arid environments.

Quality of substrate and forest structure determine macrofungal richness along a gradient of management intensity in beech forests

The richness of saproxylic species is commonly found to be compromised in managed forests. However, it is often less clear if this reflects local scarcity of high quality deadwood objects or changes to the overall forest structure. Further, anthropogenic and natural drivers working at the landscape scale may have a strong impact. Hence, it is difficult to give detailed advice on how to conserve biodiversity in a cost-effective manner. Here we explored macrofungal richness on deadwood across a gradient of forest management intensity in Danish Fagus sylvatica forests. We aimed to disentangle the importance of habitat quality per se from the effects of variables recorded at the forest stand and landscape scales. Data was collected from 40 beech stands, each representing one of four broad management types: conventionally managed, near-to-nature managed, recently unmanaged and long unmanaged. Stands were aggregated within six larger forest clusters, to account for variation at the landscape scale. Fungal species were recorded as fruitbodies on deadwood at five decay stages. We found that the four management types showed strong differences in fungal richness, deadwood volume and forest structure, with long unmanaged stands having notably higher structural complexity and species richness. Fungal species richness and presence of red-listed fungi appeared to be mainly driven by deadwood volume, tree species and decay stage, but some stand-level variables such as canopy gaps, basal area and stand age were also of importance. Lying coarse deadwood had the highest species richness while standing coarse woody debris and fine deadwood had lower species density. Saproxylic fungal richness on individual deadwood objects was largely affected by resource quality and size, which is often limited in managed forests. Our results indicate that the best measure to increase fungal species richness, especially in managed stands, is to increase the amount of large diameter deadwood.

Applicability of the European Environmental Footprint (EF) methodology in Southern Mediterranean countries—learnings and recommendations for enabling EF-compliant studies in regions outside of Europe

The European Commission is thinking about policy options for the European Environmental Footprint (EF) method and aims for a broad support. The SwitchMed initiative is a programme with the overall objective to facilitate the shift towards sustainable consumption and production in the Southern Mediterranean region. One of the objectives of this initiative, carried out in Egypt, Lebanon, Morocco, and Tunisia, is to facilitate access of companies from this region to the outcomes of the EF Rules pilot phase. The project was composed of three consecutive phases: (I) awareness raising; (II) local pilots; and (III) dissemination events. The awareness raising and technical workshop activities were meant to expose national stakeholders to the potential impact of the EF system for the national economies. Next, nine environmental footprint studies for selected product categories (so-called PEF pilot studies) were performed to create local capacity and expertise. These were leather and intermediate paper product for Egypt; two studies on wine and one on intermediate paper product in Lebanon; olive oil for Morocco; and pasta, olive oil, and dairy for Tunisia. The learnings from the pilot studies were shared in national dissemination events and used to formulate recommendations for enabling EF-compliant studies in regions outside of Europe. There was high attendance to the awareness events in each country. The pilot studies showed many similarities with the European screening studies, but also important differences in the identification of most relevant impact categories, life cycle stages, and processes (‘hotspots analyses’), e.g. related to the local scarcity of water. Based on their pilot study, the local experts made concrete suggestions for shifting towards more sustainable consumption and production. One of the biggest successes of this project is that a couple of these recommendations have already been taken into account by the companies. In Egypt, Lebanon, and Tunisia, a few local experts with a significant level of LCA expertise could be identified and through this project we managed to create local PEF capacity too. In Morocco, more assistance was needed to finish the pilot study. This project made clear that the current ‘PEF and OEF methods’ have serious drawbacks for regions other than Europe. The rules of the EF method need to be reconsidered in order to enable EF-compliant studies in regions outside of Europe. In short, we recommend:

Sowing the "CEED"s of a more diverse biomedical workforce: The Career Education and Enhancement for Health Care Research Diversity (CEED) program at the University of Pittsburgh.

The need to diversify the biomedical research workforce is well documented. The importance of fostering the careers of fledgling underrepresented background (URB) biomedical researchers is evident in light of the national and local scarcity of URB scientists in biomedical research. The Career Education and Enhancement for Health Care Research Diversity (CEED) program at the University of Pittsburgh Institute for Clinical Research Education (ICRE) was designed to promote career success and help seal the "leaky pipeline" for URB researchers. In this study, we aimed to quantify CEED's effect on several key outcomes by comparing CEED Scholars to a matched set of URB ICRE trainees not enrolled in CEED using data collected over 10 years. We collected survey data on CEED Scholars from 2007 to 2017 and created a matched set of URB trainees not enrolled in CEED using propensity score matching in a 1:1 ratio. Poisson regression was used to compare the rate of publications between CEED and non-CEED URB trainees after adjusting for baseline number of publications. CEED has 45 graduates. Seventy-six percent are women, 78% are non-White, and 33% are Hispanic/Latino. Twenty-four CEED Scholars were matched to non-CEED URB trainees. Compared to matched URB trainees, CEED graduates had more peer-reviewed publications (p=0.0261) and were more likely to be an assistant professor (p=0.0145). Programs that support URB researchers can help expand and diversify the biomedical research workforce. CEED has been successful despite the challenges of a small demographic pool.

Outside Directors at Early-Stage Startups

We document substantial variation across startups in whether and when they appoint outside directors, and the type of directors they appoint. The startup-director match depends on professional connections and individual experience profiles. Early-stage investors are more likely to serve as outside directors when there is a local scarcity of directors. Outside directors leverage their professional connections to attract new investors, directors, top executives, and potential acquirers for startups. Overall, presence of an early-stage outside director is associated with better funding outcomes and higher probability of exit through IPO, although presence of an investor-director makes exit via acquisition more likely.

Is Environmental Hostility in the Eyes of the Beholder? Foreignness, Environmental Perception and Response Mechanisms in Nigeria’s Banking Industry

Environmental hostility is posited to halt firms’ development and growth. This leads to the expectations that foreign firms that developed their capabilities in more munificent environments and are able to draw on resources via their global network to compensate for local scarcity would emerge as the predominant competitors in hostile environments. The dominance of local banks of Nigeria’s banking industry conflicts this theoretical expectation. An exploratory study points at differences between foreign and local firms in their perception of Nigeria’s environmental conditions and their subsequent responses to environmental hostility. We use this insight to advance a typology of environmental hostility distinguished by the effectiveness of response mechanisms employed by local and foreign firms to confront it, and employ it to explain variations in the competitive outcomes between foreign and local firms across environments with different types of hostility.

Academic Inventors and the Antecedents of Green Technologies. A Regional Analysis of Italian Patent Data

This work investigates the knowledge generation mechanisms underlying the creation of green technologies (GTs) in Italian NUTS 3 regions. We hypothesise that local knowledge spillovers from non-green technological areas positively influence the generation of inventions in green domains, since the latter occur as the outcome of a recombination process among a wide array of technological domains. In addition, we hypothesise that the involvement of academic inventors in patenting activity bears positive effects on the generation of GTs, because inventors are able to manage the recombination process across different, and not necessarily related, technological domains. We also investigate whether academic inventors mitigate the impact of local spillovers from non-green knowledge on the generation of GTs. The results suggest that local spillovers from non-green technological domains as well as the involvement of academic inventors in patenting activity bear positive direct effects on the generation of GTs. We also find that academic inventors compensate for local scarcity of spillovers from non-green technological areas.

DESIGNED OF CONCRETE DISTRIBUTOR LEVEL B15 WITH MEDICAL GLASS AGGREGATES AND CRUSHED SAND

The project has built and found suitable mix proportion for compacted glassconcrete, corresponding to Soundness B15 of normal concrete by laboratory method. The experimental gradations were used 5% or 10% cement content with the control (witnessing) gradation. The results of the study: finding the suitable components to create glass-concrete, using glass aggregate and grinded sand for the same Soundness as B15; Handling medical-glass-bottles and contributing to handle the local scarcity of sand, making a new construction product that is highly applicable in practice. However, for more efficient use, additional tests of tensile strength and other related properties must be carried out.

Plant factories versus greenhouses: Comparison of resource use efficiency

Research on closed plant production systems, such as artificially illuminated and highly insulated plant factories, has offered perspectives for urban food production but more insight is needed into their resource use efficiency. This paper assesses the potential of this ‘novel’ system for production in harsh climates with either low or high temperatures and solar radiation levels.The performance of plant factories is compared with cultivation in traditional greenhouses by analysing the use of resources in the production of lettuce. We applied advanced climate models for greenhouses and buildings, coupled with a lettuce model that relates growth to microclimate. This analysis was performed for three different climate zones and latitudes (24–68°N).In terms of energy efficiency, plant factories (1411MJkg−1 dry weight) outperform even the most efficient greenhouse (Sweden with artificial illumination; 1699MJkg−1 dry weight). Additionally, plant factories achieve higher productivity for all other resources (water, CO2 and land area). With respect to purchased energy, however, greenhouses excel as they use freely available solar energy for photosynthesis. The production of 1kg dry weight of lettuce requires an input of 247kWhe in a plant factory, compared to 70, 111, 182 and 211kWhe in greenhouses in respectively the Netherlands, United Arab Emirates and Sweden (with and without additional artificial illumination).The local scarcity of resources determines the suitability of production systems. Our quantitative analysis provides insight into the effect of external climate on resource productivity in plant factories and greenhouses. By elucidating the impact of the absence of solar energy, this provides a starting point for determining the economic viability of plant factories.

Frigate birds track atmospheric conditions over months-long transoceanic flights.

Understanding how animals respond to atmospheric conditions across space is critical for understanding the evolution of flight strategies and long-distance migrations. We studied the three-dimensional movements and energetics of great frigate birds (Fregata minor) and showed that they can stay aloft for months during transoceanic flights. To do this, birds track the edge of the doldrums to take advantage of favorable winds and strong convection. Locally, they use a roller-coaster flight, relying on thermals and wind to soar within a 50- to 600-meter altitude band under cumulus clouds and then glide over kilometers at low energy costs. To deal with the local scarcity of clouds and gain longer gliding distances, birds regularly soar inside cumulus clouds to use their strong updraft, and they can reach altitudes of 4000 meters, where freezing conditions occur.

Occurrence and flow of groundwater in crystalline rocks of Sardinia and Calabria (Italy): an overview of current knowledge

Crystalline rocks constitute aquifers that are of interest for water supply in many countries. In Italy, the hydrogeological characteristics of crystalline rocks are not well known and the interest in these aquifers is generally scarce. Nevertheless, the large extent of these rocks in Sardinia and Calabria regions and the local scarcity of water resources justify this preliminary analysis. Crossing the information derived by the available data on climate conditions, type of crystalline rock, structural setting, characteristics of wells and springs, base flow of streams and rivers and pumping test results, a preliminary quantification of the potential yield of the crystalline aquifers of both regions was performed. The processing of data involving different aspects confirmed that the crystalline rocks of Sardinia and Calabria form low-permeability aquifers where groundwater circulation occurs in the weathered layer and, mainly, in the most fissured layers closest to the surface. In the heavily fractured zones, it was seen that the groundwater flow is more active and can also occur at a greater depth. Groundwater mainly outflows in the valleys, feeding streams, numerous low discharge springs and surrounding aquifers. Climate, rock covers and tectonic style influence the aquifer yield, which has been evaluated herein to range from 1 to 2 L/s per km2 and from 2 to 12 L/s per km2 in Sardinia and Calabria, respectively. This preliminary characterization shows that there are reasons to deepen the present knowledge on these aquifers in order to optimize the present use of their groundwater resources