Urban tourism and population change: Gentrification in the age of mobilities

The prepandemic unbridled growth of tourism has triggered a significant debate regarding the future of cities; several authors suggest that neighbourhood change produced by tourism should be conceived as a form of gentrification. Yet research on population shifts—a fundamental dimension of gentrification—in such neighbourhoods is scarce. Our exploration of the Gòtic area in Barcelona, using quantitative and qualitative techniques, reveals a process of population restructuring characterised by a decrease of long-term residents and inhabited dwellings, and the arrival of young and transnational gentrifiers that are increasingly mobile and form a transient population. We then use some insights from the mobilities literature to make sense of these results. In the gentrification of the Gòtic, the attractiveness of the area for visitors and for a wider palette of transnational dwellers feeds one another, resulting in an uneven negotiation whereby more wealthy and ‘footloose’ individuals gain access and control of space and housing over less mobile and more dependent populations.info:eu-repo/semantics/publishedVersio

SOILSENSE handheld device for soil monitoring

Soil is a precious, essentially non-renewable, resource presently endangered by human activities. The road to protection goes through knowledge: there is the need to raise the global understanding of the importance of soil. Therefore, diffuse measurement of soil properties is central to soil conservation and management. We present a device tailored to monitor the soil quality by adopting a low-cost open-source multi-sensor approach. The device measures in the field soil temperature, moisture, density and pH. Furthermore, the device has a penetrometer to obtain a depth-resolved soil hardness characterization down to 60cm from the surface. The device is controlled via Bluetooth by a custom-built Android App. The application georeferences each data and uploads the generated-les to a server for data elaboration aimed to build and populate a map with all the collected soil quality measurements. The device is equipped with a temperature/moisture sensor, a 0-5kg load cell used as weight scale for density measurements, a reflectance spectra sensor for automatic reading pH test strips and, on the bottom side, a penetrometric tip mounted on a 100kg load cell coupled with an optical time-of-flight sensor for depth-referenced penetrometer measurements. Preliminary test evidenced good correlation between in-the-field observations and traditional laboratory tests. The device is easily also by unexperienced users, allowing for applications both in agronomic and in environmental fields, ranging from educational purposes and ICT learning of soil sciences to scientific projects related to soil monitoring and awareness raising Citizen Science initiatives

Multi-pass Laser Raman Spectroscopy for Combustion Diagnostic

In this paper is proposed a laser-based system to perform a real time Raman spectroscopy applied to in-line combustion diagnostic. This approach is widely used for solid and liquid analysis; the problem related to gas samples is the low density since the amount of Raman scattering is proportional to the quantity of molecules in the matter-light interaction region. Our setup is based on a multi-pass cell (designed to increase the collected signal) that allows high-frequency acquisitions

Super Earths, M-Stars and Photosynthetic Bacteria

Within the atmosphere in a test tube project, we are performing laboratory simulations trying to replicate the environmental conditions of an Earth-like planet orbiting around the mean habitable zone of an M star in order to understand what kind of biomarkers could be revealed by different biotypes, if present, living therein. We describe the laboratory set-up and the the methods we used in order to analyze the O2 and CO2 photosynthetic balance using atypical photosynthetic organisms and preliminary results

A New Remote Sensing-Based System for the Monitoring and Analysis of Growth and Gas Exchange Rates of Photosynthetic Microorganisms Under Simulated Non-Terrestrial Conditions

Oxygenic photosynthetic microorganisms are a focal point of research in the context of human space exploration. As part of the bioregenerative life-support systems, they could have a key role in the production of breathable O2, edible biomasses and in the regeneration of CO2 rich-atmospheres and wastewaters produced by astronauts. The test of the organism\u2019s response to simulated physico-chemical parameters of planetary bodies could also provide important information about their habitability potential. It is believed that the success of future planetary and space missions will require innovative technologies, developed on the base of preliminary experiments in custom-made laboratory facilities. In this context, simulation chambers will play a pivotal role by allowing the growth of the microorganisms under controlled conditions and the evaluation in real-time of their biomass productivity and impact on atmosphere composition. We here present a system capable of addressing these requirements with high replicability and low costs. The setup is composed by three main parts: 1) a Star Light Simulator, able to generate different light intensities and spectra, including those of non-solar stars; 2) an Atmosphere Simulator Chamber where cultures of photosynthetic microorganisms can be exposed to different gas compositions; 3) a reflectivity detection system to measure from remote the Normalized Difference Vegetation Indexes (NDVI). Such a setup allows us to monitor photosynthetic microorganism\u2019s growth and gas exchange performances under selected conditions of light quality and intensity, temperature, pressure, and atmospheres simulating non-terrestrial environments. All parameters are detected by remote sensing techniques, thus without interfering with the experiments and altering the environmental conditions set. We validated the setup by growing cyanobacteria liquid cultures under different light intensities of solar illumination, collecting data on their growth rate, photosynthetic activity, and gas exchange capacity. We utilized the reflectivity detection system to measure the reflection spectra of the growing cultures, obtaining their relative NDVI that was shown to correlate with optical density, chlorophyll content, and dry weight, demonstrating the potential application of this index as a proxy of growth

Oxygenic photosynthetic responses of cyanobacteria exposed under an M-dwarf starlight simulator: Implications for exoplanet’s habitability

Introduction: The search for life on distant exoplanets is expected to rely on atmospheric biosignatures detection, such as oxygen of biological origin. However, it is not demonstrated how much oxygenic photosynthesis, which on Earth depends on visible light, could work under spectral conditions simulating exoplanets orbiting the Habitable Zone of M-dwarf stars, which have low light emission in the visible and high light emission in the far-red/near-infrared. By utilizing cyanobacteria, the first organisms to evolve oxygenic photosynthesis on our planet, and a starlight simulator capable of accurately reproducing the emission spectrum of an M-dwarf in the range 350-900 nm, we could answer this question. Methods: We performed experiments with the cyanobacterium Chlorogloeopsis fritschii PCC6912, capable of Far-Red Light Photoacclimation (FaRLiP), which allows the strain to harvest far-red in addition to visible light for photosynthesis, and Synechocystis sp. PCC6803, a species unable to perform this photoacclimation, comparing their responses when exposed to three simulated light spectra: M-dwarf, solar and far-red. We analysed growth and photosynthetic acclimation features in terms of pigment composition and photosystems organization. Finally, we determined the oxygen production of the strains directly exposed to the different spectra. Results: Both cyanobacteria were shown to grow and photosynthesize similarly under M-dwarf and solar light conditions: Synechocystis sp. by utilizing the few photons in the visible, C. fritschii by harvesting both visible and far-red light, activating the FaRLiP response. Discussion: Our results experimentally show that an M-dwarf light spectrum could support a biological oxygen production similar to that in solar light at the tested light intensities, suggesting the possibility to discover such atmospheric biosignatures on those exoplanets if other boundary conditions are met

Inhibitory role of the serotoninergic system in hypoglycaemia-induced growth hormone release in the dog

The effect of functional activation of the serotoninergic system on base line plasma growth hormone (GH) levels and the participation of serotonin (5 HT) in the GH response evoked by insulin induced hypoglycaemia were studied in the unanaesthetized dog with the aid of a specific and sensitive homologous radioimmunoassay method. In 4 dogs, intravenous injection of insulin (0.4 IU/kg iv) or infusion of L tryptophan (TP, 2.0 g over 30 min) showed the latter stimulus to be far less potent in eliciting growth hormone (cGH) release. Intravenous injection of L 5 hydroxytryptophan (5 HTP, 10 mg/kg iv) in 5 dogs induced a clear cut rise in cGH, but was accompanied by striking side effects. In 9 dogs, administration of p chlorophenylalanine (PCPA, 100 mg/kg po daily x 5 days), an inhibitor of 5 HT synthesis, did not modify base line cGH and glucose levels, caused a marked decrease of blood 5 HT and resulted in a magnification of the insulin induced cGH release. In 8 dogs, similarly treated with PCPA, administration of 5 HTP (10 mg/kg iv), 10 min before the hypoglycaemic stimulus, blunted the GH secretory response to the latter. Chronic feeding of a TP deficient diet in 5 dogs, was accompanied by a progessive decrease of total and 'free' plasma TP, no significant changes in base line cGH and blood glucose levels and a GH response to the insulin stimulus (0.2 IU/kg iv) almost superimposable to that elicitable in the same animals under normal conditions. TP infusion (2.0 g over 30 min) in 3 TP deficient, dogs, induced a striking reduction of the hypoglycemia induced GH release. Collectively, this study suggests that 5 HT does not have a noticeable effect on base line plasma cGH levels but exerts an inhibitory role in hypoglycemia induced cGH release