288 research outputs found

    Growth-induced electron mobility enhancement at the LaAlO3_3/SrTiO3_3 interface

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    We have studied the electronic properties of the 2D electron liquid present at the LaAlO3_3/SrTiO3_3 interface in series of samples prepared at different growth temperatures. We observe that interfaces fabricated at 650{\deg}C exhibit the highest low temperature mobility (10000 cm2/Vs\approx 10000 \textrm{ cm}^2/\textrm{Vs}) and the lowest sheet carrier density (5×1012 cm2\approx 5\times 10^{12} \textrm{ cm}^{-2}). These samples show metallic behavior and Shubnikov-de Haas oscillations in their magnetoresistance. Samples grown at higher temperatures (800-900{\deg}C) display carrier densities in the range of 25×1013 cm2\approx 2-5 \times 10^{13} \textrm{ cm}^{-2} and mobilities of 1000 cm2/Vs\approx 1000 \textrm{ cm}^2/\textrm{Vs} at 4K. Reducing their carrier density by field effect to 8×1012 cm28\times 10^{12} \textrm{ cm}^{-2} lowers their mobilites to 50 cm2/Vs\approx 50 \textrm{ cm}^2/\textrm{Vs} bringing the conductance to the weak-localization regime

    Tunable Rashba spin-orbit interaction at oxide interfaces

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    The quasi-two-dimensional electron gas found at the LaAlO3/SrTiO3 interface offers exciting new functionalities, such as tunable superconductivity, and has been proposed as a new nanoelectronics fabrication platform. Here we lay out a new example of an electronic property arising from the interfacial breaking of inversion symmetry, namely a large Rashba spin-orbit interaction, whose magnitude can be modulated by the application of an external electric field. By means of magnetotransport experiments we explore the evolution of the spin-orbit coupling across the phase diagram of the system. We uncover a steep rise in Rashba interaction occurring around the doping level where a quantum critical point separates the insulating and superconducting ground states of the system

    Brand Network Booster: A New System for Improving Brand Connectivity

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    This paper presents a new decision support system offered for an in-depth analysis of semantic networks, which can provide insights for a better exploration of a brand's image and the improvement of its connectivity. In terms of network analysis, we show that this goal is achieved by solving an extended version of the Maximum Betweenness Improvement problem, which includes the possibility of considering adversarial nodes, constrained budgets, and weighted networks - where connectivity improvement can be obtained by adding links or increasing the weight of existing connections. We present this new system together with two case studies, also discussing its performance. Our tool and approach are useful both for network scholars and for supporting the strategic decision-making processes of marketing and communication managers

    An analytical model based on radiative heating for the determination of safety distances for wildland fires

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    International audienceThe radiative heat transfer is often the main thermal impact of a wildfire on people fighting the fire or on structures. Thus, the estimation of the radiation coming from the fire font and hitting a target is of primary importance for forest and urban managers. A new flame model based on the solid flame assumption is developed by considering a finite fire front width. The realistic description of finite fire front widths allows proposing a new criterion for the estimation of the radiative impact of the fire, which is based on the ratio fire front width/ flame length, opposed to the classical approach of considering only the flame length. The new model needs to be solved numerically so an analytical approximation is proposed to obtain a simple and useful formulation of the acceptable safety distance. A sensivity analysis is conducted on the different physical and geometrical parameters used to define the flame front. This analysis shows that the flame temperature is the most sensitive parameter. The results of the analytical model are compared with the numerical solution of the flame model and previous approaches based only on flame length. The results show that the analytical model is a good approximation of the numerical approach and displays realistic estimations of the acceptable safety distance for different fire front characteristics

    Nanodot-Cavity Electrodynamics and Photon Entanglement

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    Quantum electrodynamics of excitons in a cavity is shown to be relevant to quantum operations. We present a theory of an integrable solid-state quantum controlled-phase gate for generating entanglement of two photons using a coupled nanodot-microcavity-fiber structure. A conditional phase shift of O(π/10)O(\pi/10) is calculated to be the consequence of the giant optical nonlinearity keyed by the excitons in the cavities. Structural design and active control, such as electromagnetic induced transparency and pulse shaping, optimize the quantum efficiency of the gate operation.Comment: 4 pages 3 figure

    Two-dimensional quantum oscillations of the conductance at LaAlO3/SrTiO3 interfaces

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    We report on a study of magnetotransport in LaAlO3/SrTiO3 interfaces characterized by mobilities of the order of several thousands cm2^{2}/Vs. We observe Shubnikov-de Haas oscillations that indicate a two-dimensional character of the Fermi surface. The frequency of the oscillations signals a multiple sub-bands occupation in the quantum well or a multiple valley configuration. From the temperature dependence of the oscillation amplitude we extract an effective carrier mass m1.45m^{*}\simeq1.45\,mem_{e}. An electric field applied in the back-gate geometry increases the mobility, the carrier density and the oscillation frequency.Comment: 4 pages, 4 figure

    Italian food? Sounds good! Made in Italy and Italian sounding effects on food products' assessment by consumers

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    Italian Sounding—i. e., the Italian appearance of a product or service brand irrespective of its country of origin—represents a global market phenomenon affecting a wide range of economic sectors, particularly the agro-food sector. Although its economic impact has been repeatedly stressed from different points of view (policy, economy, culture, etc.), systematic scientific knowledge regarding its social–psychological bases is lacking. Three studies carried out in three different countries (Italy, China, and USA) address this literature gap. Different consumer groups (both native and/or non-native) are targeted regarding major product categories pre-selected categories, which are the major Italian food goods within the specific country according to piloting (oil and/or pasta). In each study, the main independent variable (product version) has been manipulated by presenting real product images (previously pre-selected within the tested food category in each country market), whose “Italianness” degree is effectively manipulated by the main study variable (product version) across three or four levels (Protected Designation of Origin Made in Italy, Made in Italy, Italian Sounding, and Generic Foreign). Main hypotheses are tested via a survey with the specific product images administered to samples in Italy (N = 204, 148 Italians and 56 non-Italians), China (N = 191, 100 Chinese and 91 non-Italian expatriates in China), and the USA (N = 237 US citizens). Across the three studies, results show that Made in Italy products, compared to the other ones, are advantaged in terms of the main dependent variables: reputation profile, general reputation, attitude, and willingness to pay (WTP). Moreover, Italian Sounding products are endowed with corresponding significant advantages when compared to the Generic Foreign by non-Italian samples (although to a different degree according to the different sub-samples). Results reveal the specific social–psychological profile of Italian Sounding products in terms of either weaknesses or strengths when compared to both Made in Italy products and Generic Foreign ones, differently in the eyes of Italian and non-Italian consumers across different countries. Finally, consistently across the three studies, the extent to which a food product is perceived to be Italian increases consumers' WTP for that product, and this effect is consistently mediated by the product's reputation

    Flood risk management in Italy: challenges and opportunities for the implementation of the EU Floods Directive (2007/60/EC)

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    Abstract. Italy's recent history is punctuated with devastating flood disasters claiming high death toll and causing vast but underestimated economic, social and environmental damage. The responses to major flood and landslide disasters such as the Polesine (1951), Vajont (1963), Firenze (1966), Valtelina (1987), Piedmont (1994), Crotone (1996), Sarno (1998), Soverato (2000), and Piedmont (2000) events have contributed to shaping the country's flood risk governance. Insufficient resources and capacity, slow implementation of the (at that time) novel risk prevention and protection framework, embodied in the law 183/89 of 18 May 1989, increased the reliance on the response and recovery operations of the civil protection. As a result, the importance of the Civil Protection Mechanism and the relative body of norms and regulation developed rapidly in the 1990s. In the aftermath of the Sarno (1998) and Soverato (2000) disasters, the Department for Civil Protection (DCP) installed a network of advanced early warning and alerting centres, the cornerstones of Italy's preparedness for natural hazards and a best practice worth following. However, deep convective clouds, not uncommon in Italy, producing intense rainfall and rapidly developing localised floods still lead to considerable damage and loss of life that can only be reduced by stepping up the risk prevention efforts. The implementation of the EU Floods Directive (2007/60/EC) provides an opportunity to revise the model of flood risk governance and confront the shortcomings encountered during more than 20 yr of organised flood risk management. This brief communication offers joint recommendations towards this end from three projects funded by the 2nd CRUE ERA-NET (http://www.crue-eranet.net/) Funding Initiative: FREEMAN, IMRA and URFlood

    Food Reputation and Food Preferences: Application of the Food Reputation Map (FRM) in Italy, USA, and China

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    Given the food challenges that society is facing, we draw upon recent developments in the study of how food reputation affects food preferences and food choices, providing here a starting standard point for measuring every aspect of food reputation in different cultural contexts across the world. Specifically, while previous attempts focused either on specific aspects of food or on measures of food features validated in one language only, the present research validates the Food Reputation Map (FRM) in Italian, English and Chinese over 2,250 participants worldwide. Here we successfully measure food reputation across 23 specific indicators, further grouped into six synthetic indicators of food reputation. Critically, results show that: (a) the specific measurement tool of food reputation can vary across cultural contexts, and that (b) people's reputation of food products or categories changes significantly across different cultural contexts. Therefore, in order to understand people's food preferences and consumption, it is important to take into account the repertoire of cultural differences that underlies the contexts of analysis: the three context-specific versions of the FRM presented here effectively deal with this issue and provide reliable context-specific insights on stakeholders' interests, perspectives, attitudes and behaviors related to food perceptions, assessment, and consumption, which can be effectively leveraged to foster food sustainability

    Weather and Climate Change Drive Annual Variation of Reproduction by an Aerial Insectivore

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    For many bird species, but especially aerial insectivores, reproduction depends on weather. Climate change is likely to intensify effects, but with uncertain consequences. We report 22 years of data on Eastern Kingbird (Tyrannus tyrannus) reproduction for two populations located in different hygric environments undergoing climate change; mesic central New York, USA, (NY; 12 years) and xeric southeastern Oregon, USA, (OR: 10 years). Laying date became earlier with increasing temperature in the 30-day period preceding laying in identical fashion at both sites, and in years of early laying, clutch size was larger, length of laying season increased, and failed initial nesting attempts were more often replaced. High temperature in the 10-days preceding mean laying date was associated with shorter laying seasons, while a site by 10-day temperature interaction reflected an increase and decrease of clutch size with increasing 10-day temperature in NY and OR, respectively. Seasonal rate of clutch size decline was higher when the laying season was short but also slowed in xeric OR when rain was abundant in the 10-days prior to mean laying date. Nest predation drove annual variation in young fledged/nest, but the latter also increased and decreased with increasing maximum temperature during the nestling phase in mesic NY and xeric OR, respectively. Potential effects of climate change on kingbird populations are thus high given the dependence of reproduction on weather, and climate change likely contributed to declines of kingbirds in OR. Declines of kingbirds in NY appear unrelated to warming climates because higher temperatures advanced laying dates and yielded greater nest productivity. However, length of laying season declined across years at both sites, and thus early season gains may be negated by poor conditions late in the season that may be causing shorter laying seasons. Further work is needed to identify causes for the latter changes
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