A new dielectric effect in viscous liquids

An accurate experimental and theoretical study has been performed about a phenomenon, not previously reported in the literature, occurring in highly viscous liquids: the formation of a definite pipe structure induced by the passage of a heavy body, this structure lasting for quite a long time. A very rich phenomenology (including mechanical, optical and structural effects) associated with the formation of the pipe has been observed in different liquids. Actually, the peculiar dynamical evolution of that structure does not appear as a trivial manifestation of standard relaxation or spurious effects. In particular we have revealed different time scales during the evolution of the pipe and a non-monotonous decrease of the persistence time with decreasing viscosity (with the appearance of at least two different maxima). We put forward a microscopic model, consistent with the experimental data, where the pipe behaves as a "dielectric shell" whose time evolution is described through a simple thermodynamical approach, predicting several properties effectively observed.Comment: 14 pages, 6 figures. arXiv admin note: text overlap with arXiv:0812.436

Private land conservation policies: navigating from global gaps to local perceptions and needs.

Despite efforts to reverse the current global environmental crisis that threatens biodiversity and human well-being, many indicators suggest we are still far from changing the main trajectory towards sustainability. With privately owned land covering large areas of the world, private land conservation (PLC) has been recognized as a promising strategy to complement protected area networks in meeting biodiversity conservation objectives. However, the overall success of PLC depends on designing and implementing a suite of policies according to geographical contexts and to the needs, values, and capabilities of different stakeholders. In my doctoral thesis, I aim to identify challenges and opportunities to foster PLC at different geographical scales by understanding the main trends and gaps in a global PLC literature review and by assessing landowners’ preferences and needs at national and local levels. In order to do so I followed transdisciplinary approaches, combining theories and methods from the natural and social sciences in collaboration with stakeholders outside academia. In the first chapter, I carried out an in-depth global literature review of PLC scientific articles. My results revealed that most studies have focused on limited geographical contexts and policies. This highlighted the need for i) assessing a more diverse set of policy instruments to increase participation; ii) increasing stakeholders’ engagement in research to better inform PLC policymaking; iii) better understanding barriers and opportunities to foster PLC in underrepresented regions, such as South America. Based on findings from my first chapter, I conducted two empirical studies at local and national levels in Uruguay, a country where most of the land is privately owned (~96%). While the importance of voluntary PLC has been recognized by law in 2017, in Uruguay PLC policy has not been developed or implemented yet. Hence, there is a need to understand context-specific landowners’ preferences for voluntary PLC to inform policy-making at early stages. In the second chapter, I applied qualitative methods to explore landowners´ perceptions, motivations and needs for voluntary conservation in a cultural landscape in north-eastern Uruguay. I found that landowners considered themselves and their neighbours as local environmental stewards and their main needs to support biodiversity conservation were mostly related to enhance land management and social cohesion. My results revealed that strengthening existing links between people and nature and addressing local rural development needs could confer both social and conservation benefits in a just and sustainable way. In the third chapter, I used stated preference methods to assess landowners’ preferences for hypothetical voluntary PLC policies at the national level in Uruguay. My results revealed that landowners had high willingness to engage in voluntary conservation initiatives if future policies would meet their heterogeneous preferences. Offering a diverse set of policy instruments, mainly non-monetary incentives, while fostering networks and collaboration with different stakeholders could help increase participation and long-term engagement in voluntary PLC. To conclude, by following a transdisciplinary approach my thesis contributes to identifying and addressing research gaps in PLC at different scales with practical implications for biodiversity conservation, sustainability, and policymaking in Uruguay and elsewhere in the world in similar contexts. In addition, my thesis highlights the need for future research to disentangle the main contextdependent dimensions driving PLC effectiveness but also to identify general principles that could inform the design, governance and implementation of legitimate and equitable policies across contexts.Agencia Nacional de Investigación e InnovaciónDissertation completion grant (2020) University of Helsink

Health policy under the microscope: a micro policy design perspective

The comparative study of health policy has focused mainly on the macrostructural dimensions of health systems and reforms that have sought to change these organizational arrangements. Thus, a great deal of attention has been paid to the multiple models of insurance against sickness risks and various modes of organizing and financing healthcare providers. However, little attention has been paid to policy tools and policy design in the health policy domain. This research gap largely impedes a focus on the micro (granular) dimension of health policy, although this is the level at which health policies impact reality and thus deliver progress toward the expected goals. Such a focus on the micro dimension could not only allow a finer-grained comparison of how health systems work but also shed light on how capable health policies are of achieving the expected outcomes. This paper fills this gap by presenting an analytical framework capable of illuminating the granular dimension of policy design (the instrumental delivery package) and shows the analytical relevance of the framework by applying it to the designs of maximum waiting time guarantee and vaccination mandate policies

We did well enough. Systemic reforms, changes in recruitment procedures and the evolution of Italian political science

Italian political science has evolved over time, dealing with various reforms and changes in the structure of academic careers and procedures for recruitment that have characterised the recent decades of the Italian university system. This paper reflects on how these changes have challenged the foundational identity of Italian political science and how they have influenced its development as a community of scholars. Three relevant dynamics emerge: the shift from a national and centralised community to a set of local networks of scholars, the capacity to perform well in terms of professional standards, and the risk that the capacity to reproduce the discipline’s identity, or at least its foundational core, could be significantly weakened

Synthetic sustainability index (SSI) based on life cycle assessment approach of low impact development in the Mediterranean area

AbstractClimate change and the processes of urbanization alter the hydrologic and hydraulic regime of runoffs formation in urban areas. Low impact infrastructure development (LID) contributes to achieving conditions of invariance hydrological and hydraulics. The purpose of this work is to identify an index of synthetic sustainability (SSI) based on life cycle assessment (LCA). Such LCA evaluates design alternatives through the comparison of the different values of the SSI. The proposed methodology allows the evaluation of the SSI attributing to the individual layers of the LIDs different weights and taking into account both of the influence that each of them perform on invariance hydrologic and hydraulic both of the LCA normalized output. In this paper is showed a methodological implementation obtained by the analysis of a green roof and a permeable pavement. This green roof has been realized, on real scale, in the Urban Hydrology Experimental Park in University of Calabria (Italy)

Ab initio Study of Misfit Dislocations at the SiC/Si(001) Interface

The high lattice mismatched SiC/Si(001) interface was investigated by means of combined classical and ab initio molecular dynamics. Among the several configurations analyzed, a dislocation network pinned at the interface was found to be the most efficient mechanism for strain relief. A detailed description of the dislocation core is given, and the related electronic properties are discussed for the most stable geometry: we found interface states localized in the gap that may be a source of failure of electronic devices

No good recommendation without a mechanistic explanation? : the case of higher education governance

In higher education, reforms have long been driven by the theory that system performance depends on governance design; yet it remains far from clear which arrangements can actually deliver results, as shown in the analysis of various streams of research devoted to assessing performance in higher education. We reason that such a question can be better answered if research aims for a mechanistic explanation and operationalizes it to avoid the shortcomings of both \u2018variable-oriented\u2019 and \u2018case-oriented\u2019 strategies. We therefore develop a \u2018diversity-oriented\u2019 mechanistic framework that explains differences in performance by differences in policy tool mixes, which we define as governance regimes. This set of policy tools is meant as a configuration of properties of delivery vehicles, decision-making design, and accountability design. Such an explanatory focus has many advantages: policy tools are manipulable, as they depend on political and administrative decisions; moreover, they are efficient causes, as they trigger mechanisms at the individual level that directly account for both individual and institutional behavior and, hence, performance. Tool-based explanations therefore can more easily allow for policy learning and transfer than can \u2018remote\u2019 constitutional, historical, or cultural accounts

Localized holes and delocalized electrons in photoexcited inorganic perovskites: Watching each atomic actor by picosecond X-ray absorption spectroscopy

We report on an element-selective study of the fate of charge carriers in photoexcited inorganic CsPbBr3 and CsPb(ClBr)3 perovskite nanocrystals (NCs) in toluene solutions using time-resolved X-ray absorption spectroscopy with 80 ps time resolution. Probing the Br K-edge, the Pb L3-edge and the Cs L2-edge, we find that holes in the valence band are localized at Br atoms, forming small polarons, while electrons appear as delocalized in the conduction band. No signature of either electronic or structural changes are observed at the Cs L2-edge. The results at the Br and Pb edges suggest the existence of a weakly localized exciton, while the absence of signatures at the Cs edge indicates that the Cs+ cation plays no role in the charge transport, at least beyond 80 ps. These results can explain the rather modest charge carrier mobilities in these materials.Comment: 19 pages, 3 figure

Self-assembled InAs quantum dots formed by molecular beam epitaxy at low temperature and postgrowth annealing

Self-assembled InAs quantum dots are grown at low temperature (LT) by molecular beam epitaxy (MBE) on GaAs substrates. The growth is in situ monitored by reflection high-energy electron diffraction, and ex situ evaluated by atomic force microscopy for the morphological properties, and by high-resolution x-ray diffraction for the structural properties. While two monolayers as-grown LT (250 degrees C) InAs layers exhibit shallow mounds due to the low adatom migration length at low temperature, well-developed InAs dots are formed after postgrowth annealing above 450 degrees C. The structural quality of the LT GaAs matrix grown on top and of the embedded InAs dot layer is improved when a 3 nm GaAs interlayer is deposited (at 480 degrees C) on the InAs dots and subsequently annealed at 580 degrees C before LT GaAs overgrowth. These high structural quality LT-grown InAs dots are considered for applications in high-speed optical modulators and switches operating at low power by combining the high optical nonlinearity of quantum dots with the ultrafast optical response provided by LT growth in MB