A continuous latitudinal energy balance model to explore non-uniform climate engineering strategies

In order to investigate the effects of solar radiation management (SRM) technologies for climate engineering, an analytical model describing the main latitu8 dinal dynamics of the Earth’s climate with closed-loop control has been developed. The model is a time-dependent Energy BalanceModel (EBM) with latitudinal resolution and allows for the evaluation of non-uniform climate engineering strategies. The resulting partial differential equation is solved using a Green’s function approach. This model offers an efficient analytical approach to design strategies that counter act climate change on a latitudinal basis to overcome regional disparities in cooling. Multi-objective analyses are considered and time-dependent analytical expressions of control functions with latitudinal resolution can be obtained in several circumstances. Results broadly comparable with the literature are found, demonstrating the utility of the model in rapidly assessing new climate engineering controls laws and strategies. For example, the model is also used to quickly assess the trade-off between the number of degrees of freedom of SRM and the rms error in latitudinal temperature compensation. Moreover, using the EBM the dynamics of the ice line can be investigated and a Lyapunov stability analysis is employed to estimate the maximum reduction of solar insolation through climate engineering before the current climate falls into an ice-covered state. This provides an extreme operational boundary to future climate engineering ventures

Space-Enhanced Solar Power for Equatorial Regions

This paper examines the concept of solar mirrors in a Earth orbit to provide solar farms with additional solar power during the hours of darkness. The design of the orbit is key for the purposes of the mission: the mirror needs continuous access to the Sun and the solar farm simultaneously. Therefore, orbits with high-eccentricity will be considered to increase the visibility time. Also, since the most convenient locations for solar power farms are about the equator, a suitable orbit should have a low inclination. This issue can be addressed through the concept of anti-heliotropic orbits that exploits mainly solar radiation pressure perturbations to generate highly-eccentric equatorial orbits able to maintain the orientation with respect to the Sun. The considered configuration consists in two space mirrors in a flower constellation rotating with the Earth to deliver a repeat ground track

Space-Enhanced Solar Power for Equatorial Regions

This paper examines the concept of solar mirrors in a Earth orbit to provide solar farms with additional solar power during the hours of darkness. The design of the orbit is key for the purposes of the mission: the mirror needs continuous access to the Sun and the solar farm simultaneously. Therefore, orbits with high-eccentricity will be considered to increase the visibility time. Also, since the most convenient locations for solar power farms are about the equator, a suitable orbit should have a low inclination. This issue can be addressed through the concept of anti-heliotropic orbits that exploits mainly solar radiation pressure perturbations to generate highly-eccentric equatorial orbits able to maintain the orientation with respect to the Sun. The considered configuration consists in two space mirrors in a flower constellation rotating with the Earth to deliver a repeat ground track

Robust and adaptive control strategies for closed-loop climate engineering

Climate engineering aims to offset human-driven climate change through engineering interventions. This thesis focuses on the deployment of Solar Radiation Management (SRM) methods which aim to counteract radiative forcing generated by the concentration of atmospheric CO2. The climate system is investigated as a closed-loop control problem with uncertainties in its dynamics mitigated by robust and adaptive control strategies. Indeed, an adaptive controller for climate engineering is presented for the first time in a multi-variable control scheme. A low order three-box energy model is developed for the climate system to investigate such adaptive control strategies. Climate engineering measures are then deployed in 3 boxes, thus representing northern, southern and central (equatorial) bands. It is demonstrated that, through the on-line estimation of the controller parameters, adaptive control can overcome key-issues related to uncertainties of the climate model, external radiative forcing and actuator dynamics. The use of adaptive control provides a robust means of dealing with unforeseeable abrupt perturbations and the parametrisation of the model considered, while still providing bounds on stability and control performance. Importantly, the convergence of the controller is guaranteed through the Lyapunov stability criterion. Moreover, an analytical model describing the main latitudinal dynamics of the Earth’s climate with closed-loop control has been developed. This model has analytical solution and allows for quick evaluations of non-uniform climate engineering strategies. Multi-objective analyses are considered and analytical expressions for control laws with latitudinal resolution are obtained in several scenarios. Results are broadly comparable with the literature, demonstrating model’s utility in rapidly assessing climate engineering controls laws. Using the PDE model, ice line dynamics are investigated and a Lyapunov stability analysis is employed to estimate the maximum insolation reduction before the current climate falls into an ice-covered state. This provides an extreme operational boundary for future climate engineering ventures. Finally, the PDE model is employed to investigate strategies involving the deployment of space shields. The grade of obscuration provided at each latitude is estimated and an optimization process performed in order to minimize the shield size and to find the ideal orbit to counteract 2xCO2 concentration

Extracellular vesicles from mesenchymal stem cells: towards novel therapeutic strategies for neurodegenerative diseases

Neurodegenerative diseases are fatal disorders of the central nervous system (CNS) which currently lack effective treatments. The application of mesenchymal stem cells (MSCs) represents a new promising approach for treating these incurable disorders. Growing evidence suggest that the therapeutic effects of MSCs are due to the secretion of neurotrophic molecules through extracellular vesicles. The extracellular vesicles produced by MSCs (MSC-EVs) have valuable innate properties deriving from parental cells and could be exploited as cell-free treatments for many neurological diseases. In particular, thanks to their small size, they are able to overcome biological barriers and reach lesion sites inside the CNS. They have a considerable pharmacokinetic and safety profile, avoiding the critical issues related to the fate of cells following transplantation. This review discusses the therapeutic potential of MSC-EVs in the treatment of neurodegenerative diseases, focusing on the strategies to further enhance their beneficial effects such as tracking methods, bioengineering applications, with particular attention to intranasal delivery as a feasible strategy to deliver MSC-EVs directly to the CNS in an effective and minimally invasive way. Current progresses and limiting issues to the extent of the use of MSC-EVs treatment for human neurodegenerative diseases will be also revised

Sfide e potenzialità dei metodi collaborativi nella ricerca applicata ai contesti educativi multiculturali = Challenges and opportunities of collaborative research applied to multicultural educational contexts

Sul solco delle sfide attuali poste ai contesti educativi multiculturali e ai mondi della ricerca, il contributo riflette sulle potenzialità dei metodi collaborativi nella ricerca applicata in questi ambit

Loneliness, affective disorders, suicidal ideation, and the use of psychoactive substances in a sample of adolescents during the COVID-19 pandemic: A cross-sectional study

Abstract Problem: The global coronavirus (COVID‐19) pandemic has been challenging for adolescents. Indeed, with the closure of schools and social centers and reduction of extracurricular activities, increased social isolation has compounded difficulties in and with school performance, loneliness, and social networking. Increased risk of mental health problems, substance abuse, affective disorders, suicidal ideation, and suicide has been reported in adolescents. Methods: This cross‐sectional study assesses the association between loneliness, depression, anxiety, suicidal ideation, the use of social networks, and school achievement in a sample of Italian adolescents during the COVID‐19 pandemic. This study also explores emotional dysregulation through the association between affective disorders (depression and anxiety), substance use, and social networks. The sample comprises adolescents in the first and second grades of high school during the pandemic; participants received an email explaining the purpose of the e‐research. Data were collected using the Strengths and Difficulties Questionnaire, the Achenbach System of Empirically Based Assessment, and the Loneliness Scale. Findings: A total of 505 adolescents completed the web survey. Data revealed that students experienced difficulties with loneliness, problems with school achievement, and extracurricular activities. The mean scores for depression and anxiety were close to the borderline range. A total of 14.3% of adolescents intentionally harmed themselves or attempted suicide. Conclusions: This study raises concerns about the impacts of the pandemic on adolescents that require the attention of adult reference figures who deal with adolescents, such as parents, teachers, and healthcare professionals. Results indicate the necessity of providing early interventions aimed at the prevention of psychopathol ogies and the promotion of adolescent mental health due to the pandemic

Socio‐emotional, cognitive, affective disorders and substance use in a sample of students in first‐ and second‐grade high school in Italy: A comparison among students', parents', and teachers' perceptions

Abstract The closure of schools, social hubs, and extracurricular activities due to lockdown measures imposed to curb the spread of SARS‐CoV‐2, has increased the risk factors for students' mental health. This cross‐sectional study, conducted from March 2020 to March 2021, aimed to estimate socio‐emotional, cognitive, and affective disorders and substance use in a sample of first‐ and second‐grade high school students in Northern Italy. This study compared data from 284 Italian students' self‐perceptions along with the perceptions of their parents and teachers through a web‐based survey. The differences in the perceptions of the three groups (students, parents, and teachers) were analyzed using an analysis of variance test, applying a Bonferroni correction. The χ 2 test was used to assess the comparison between students, parents, and teachers in the substance use questions. The results showed statistically significant differences among the three groups. The most important outcomes were sociality, scholastic performance, extracurricular activity, emotional symptoms, affective disorders (depression and anxiety), and substance use. These findings could be interesting for the promotion of mental health and prevention of psychopathological risks in students

Design of a novel bioink suitable for the 3D printing of lymphoid cells

Introduction: For decades, in vitro 2D cell culture techniques have been employed in research, but they fail to recapitulate the complexity of natural tissues. 3D bioprinting could potentially overcome this drawback due to the possibility to control the spatial disposition of living cells and the geometry of the 3D scaffold. Materials and methods: This study reports the design and characterization of a novel bioink for extrusion bioprinting, analyzing different blend formulations composed of alginate, gelatin, and methylcellulose, suitable as cell-laden bioink for lymphoid cells, in particular those isolated from patients with Chronic Lymphocytic Leukemia (CLL). The rheological properties as a function of temperature and the printability of the formulations were investigated to define the optimal printing parameters. In vitro stability of the printed scaffolds was investigated under culture conditions and compression tests were performed on printed and bioprinted scaffolds to compare their mechanical properties with those of fresh lymphoid tissue. Finally,MEC1, aCLL cell line,was bioprinted to investigate cell viability, cell density, and cell capability to be released from the scaffold over time. Results and discussion: Results showed that, for the selected blends, good shape fidelity and printing accuracy were achieved with a limitation on the number of printed layers. Scaffolds withstood culture conditions showing stability for up to 3 weeks and their mechanical properties were similar to those of lymphoid tissues already reported in the literature. High cell viability after 21 days was observed for both MEC1 and primary peripheral mononuclear cells, confirming the possibility to use the selected formulation to successfully bioprint lymphoid cells by possibly mimicking their native lymphoid microenvironment