Analisi comparativa di due casi di studi di progetti di ricerca sugli Organismi Geneticamente Modificati in Italia e Inghilterra

Questo articolo esplora due casi di studio di progetti di ricerca, Farm Scale evaluation e OGM in Agricoltura, sugli Organismi Genticamente Modificati, e si domanda quali fattori politici, sociali ed economici hanno contribuito a costruire le risposte della scienza alla resistenza del pubblico verso gli OGM. I dati che vengono utilizzati includono, articoli di giornale, documenti governativi, articoli accademici, siti web e interviste con giornalisti e ricercatori che hanno partecipato direttamente o indirettamente a questi progetti. Paragonando questi progetti emergono sei fattori dominanti che sembrano maggiormente influire sulla capacità degli scienziati di ascoltare il pubblico. Questi includono: il governo, la posizione della scienza nel contesto culturale italiano, le aziende private, i tipi di pubblico, il ruolo dei mass media nella comunicazione scientifica, e la natura del dibattito relativo al Public Understanding of Science. In conclusione, come suggerisce Brian Wynne (2006), i discorsi relativi alla comunicazione della scienza si collocano in stretta relazione alla cultura locale relativa alla comunicazione e politica della scienza

High-resolution resonant inelastic soft X-ray scattering as a probe of the crystal electrical field in lanthanides demonstrated for the case of CeRh2Si2

The magnetic properties of rare earth compounds are usually well captured by assuming a fully localized f shell and only considering the Hund's rule ground state multiplet split by a crystal electrical field (CEF). Currently, the standard technique for probing CEF excitations in lanthanides is inelastic neutron scattering. Here we show that with the recent leap in energy resolution, resonant inelastic soft X-ray scattering has become a serious alternative for looking at CEF excitations with some distinct advantages compared to INS. As an example we study the CEF scheme in CeRh2Si2, a system that has been intensely studied for more than two decades now but for which no consensus has been reached yet as to its CEF scheme. We used two new features that have only become available very recently in RIXS, high energy resolution of about 30 meV as well as polarization analysis in the scattered beam, to find a unique CEF description for CeRh2Si2. The result agrees well with previous INS and magnetic susceptibility measurements. Due to its strong resonant character, RIXS is applicable to very small samples, presents very high cross sections for all lanthanides, and further benefits from the very weak coupling to phonon excitation. The rapid progress in energy resolution of RIXS spectrometers is making this technique increasingly attractive for the investigation of the CEF scheme in lanthanides

Direct observation of bulk charge modulations in optimally-doped Bi1.5_{1.5}Pb0.6_{0.6}Sr1.54_{1.54}CaCu2_{2}O8+δ_{8+\delta}

Bulk charge density modulations, recently observed in high critical-temperature ($T_\mathrm{c}$) cuprate superconductors, coexist with the so-called pseudogap and compete with superconductivity. However, its direct observation has been limited to a narrow doping region in the underdoped regime. Using energy-resolved resonant x-ray scattering we have found evidence for such bulk charge modulations, or soft collective charge modes (soft CCMs), in optimally doped Bi$_{1.5}$Pb$_{0.6}$Sr$_{1.54}$CaCu$_{2}$O$_{8+\delta}$ (Pb-Bi2212) around the summit of the superconducting dome with momentum transfer $q_{\parallel}\sim0.28$ reciprocal lattice units (r.l.u.) along the Cu-O bond direction. The signal is stronger at $T\simeq T_\mathrm{c}$ than at lower temperatures, thereby confirming a competition between soft CCMs and superconductivity. These results demonstrate that soft CCMs are not constrained to the underdoped regime, suggesting that soft CCMs appear across a large part of the phase diagram of cuprates and are intimately entangled with high-$T_\mathrm{c}$ superconductivity.Comment: 6 pages, 3 figures, 1 tabl

From public understanding of GMOs to scientists’ understanding of public opinion: a case study of the listening capacity of scientists in the UK and Italy

Genetically modified organisms have been accompanied by hopes and concerns regarding the potential of this technology to reshape agricultural practices, our environment and the food we eat. The controversy surrounding GMOs raised questions regarding the present and future relationship between science and society. This thesis contributes to this debate by exploring GM scientists’ thoughts about public opinion and its influence on their work. I contend that how scientists listen to public opinion is mediated by national context, which I explore through a comparison of the United Kingdom and Italy. Within the public understanding of science, and social studies of science more generally, the listening capacity of scientists has largely been ignored. Asking if, how and under what conditions GM scientists listen to public opinion on GMOs, I address this gap in the literature. A mixed method approach is used to answer these questions. This combines descriptive statistics with a range of qualitative methods, including narrative analysis, case study and situational analysis. This methodological approach is meant to bridge qualitative and quantitative methodologies, historically polarised within PUS scholarship. This thesis is structured by my own changing understanding of the listening process. Initially, I assumed a stimulus-­‐response model of scientists’ listening, in which the public talks and scientists respond. Following my data collection and analysis, I developed a new model for listening that includes three moments: hearing public opinion, interpreting it, and responding to it. Using this model, I identify two typical patterns in GM scientists’ listening process. Both of these patterns are associated with the ‘deficit model’, which scientists used differently according to their national contexts. Drawing on Jasanoff’s (2005) concept of civic epistemology, I contend that these patterns are indicative of scientists’ civic epistemologies, which are informed by a number of different factors

Magnetic excitations and phonons simultaneously studied by resonant inelastic x-ray scattering in optimally doped Bi1.5_{1.5}Pb0.55_{0.55}Sr1.6_{1.6}La0.4_{0.4}CuO6+δ_{6+\delta}

Magnetic excitations in the optimally doped high-$T_\mathrm{c}$ superconductor Bi$_{1.5}$Pb$_{0.55}$Sr$_{1.6}$La$_{0.4}$CuO$_{6+\delta}$ (OP-Bi2201, $T_\mathrm{c}\simeq 34$ K) are investigated by Cu $L_3$ edge resonant inelastic x-ray scattering (RIXS), below and above the pseudogap opening temperature. At both temperatures the broad spectral distribution disperses along the (1,0) direction up to $\sim$350~meV at zone boundary, similarly to other hole-doped cuprates. However, above $\sim$0.22 reciprocal lattice units, we observe a concurrent intensity decrease for magnetic excitations and quasi-elastic signals with weak temperature dependence. This anomaly seems to indicate a coupling between magnetic, lattice and charge modes in this compound. We also compare the magnetic excitation spectra near the anti-nodal zone boundary in the single layer OP-Bi2201 and in the bi-layer optimally doped Bi$_{1.5}$Pb$_{0.6}$Sr$_{1.54}$CaCu$_2$O$_{8+\delta}$ (OP-Bi2212, $T_\mathrm{c}\simeq96$ K). The strong similarities in the paramagnon dispersion and in their energy at zone boundary indicate that the strength of the super-exchange interaction and the short-range magnetic correlation cannot be directly related to $T_\mathrm{c}$, not even within the same family of cuprates

Optimal Cost-Preference Trade-off Planning with Multiple Temporal Tasks

Autonomous robots are increasingly utilized in realistic scenarios with multiple complex tasks. In these scenarios, there may be a preferred way of completing all of the given tasks, but it is often in conflict with optimal execution. Recent work studies preference-based planning, however, they have yet to extend the notion of preference to the behavior of the robot with respect to each task. In this work, we introduce a novel notion of preference that provides a generalized framework to express preferences over individual tasks as well as their relations. Then, we perform an optimal trade-off (Pareto) analysis between behaviors that adhere to the user's preference and the ones that are resource optimal. We introduce an efficient planning framework that generates Pareto-optimal plans given user's preference by extending A* search. Further, we show a method of computing the entire Pareto front (the set of all optimal trade-offs) via an adaptation of a multi-objective A* algorithm. We also present a problem-agnostic search heuristic to enable scalability. We illustrate the power of the framework on both mobile robots and manipulators. Our benchmarks show the effectiveness of the heuristic with up to 2-orders of magnitude speedup.Comment: 8 pages, 4 figures, to appear in International Conference on Intelligent Robots and Systems (IROS) 202

Influence of apical oxygen on the extent of in-plane exchange interaction in cuprate superconductors

In high Tc superconductors the magnetic and electronic properties are determined by the probability that valence electrons virtually jump from site to site in the CuO2 planes, a mechanism opposed by on-site Coulomb repulsion and favored by hopping integrals. The spatial extent of the latter is related to transport properties, including superconductivity, and to the dispersion relation of spin excitations (magnons). Here, for three antiferromagnetic parent compounds (single-layer Bi2Sr0.99La1.1CuO6+delta, double-layer Nd1.2Ba1.8Cu3O6 and infinite-layer CaCuO2) differing by the number of apical atoms, we compare the magnetic spectra measured by resonant inelastic x-ray scattering over a significant portion of the reciprocal space and with unprecedented accuracy. We observe that the absence of apical oxygens increases the in-plane hopping range and, in CaCuO2, it leads to a genuine 3D exchange-bond network. These results establish a corresponding relation between the exchange interactions and the crystal structure, and provide fresh insight into the materials dependence of the superconducting transition temperature.Comment: 9 pages, 4 figures, 1 Table, 42 reference

Gaussian Graphical Models: An Exploration and Application of Learning Conditional Independence

This paper is an application and exploration of how precision matrices signify conditional independence between Gaussian random variables, and what this conditional independence means for the simplification of probabilistic graphical models. We worked with atmospheric data from the National Center for Atmospheric Research (Skamarock, William C., et al., 2012) to determine conditional independence between Gaussian mean variables. We also generated variables from an ordinary differential equation system and looked at the resulting precision matrices. This research details one potential avenue to create precision matrices and probabilistic graphical models from a set of Gaussian random variables, then determine conditional independence. It also explores the setup for a problem relating precision matrices to an oscillating system of ordinary differential equations, and potential applications of this method.</p