538 research outputs found
NEW RECORDS OF NATIVE AND ALIEN VASCULAR PLANTS FROM ABRUZZO, LAZIO AND MOLISE NATIONAL PARK (ITALY) - AND ADDITIONS TO THE FLORA OF ABRUZZO AND MOLISE ADMINISTRATIVE REGIONS
The Abruzzo, Lazio and Molise National Park, a flagship conservation area in Italy, is a hotspot of floristic diversity and a crossroad for plant biogeography. In this work, as a result of recent field studies in the Park and herbarium revisions, we report 10 taxa new or confirmed for the Abruzzo administrative region, and 3 for the Molise administrative region. Moreover. 47 taxa of vascular plants (41 native and 6 alien taxa) that are new or confirmed for the flora of the Park are reported. Five taxa are excluded from the flora of the Park
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Balancing Valued Tradition With Innovation When your product is a beloved classic, how do you update it to attract new customers?
Successful companies frequently face the challenge of updating a beloved old product. Italian opera companies face this dilemma every season. Many of the best-loved operas in the repertoire are more than 100 years old. The most devoted operagoers will have seen multiple productions of the same work and have a very clear, and usually conservative, notion of what constitutes a proper production. However, making no changes would limit opera’s contemporary cultural relevance. After interviewing 15 artistic directors of Italian opera houses and studying the ticket sales of 2,627 opera productions between 1989 and 2011, we found that the most successful opera houses strategically balance alterations to core and peripheral features of traditional operas across different customer segments. In so doing, they address the need for renewal while at the same time remaining sensitive to the heterogeneity of their audience. The findings offer several actionable insights for successfully navigating the innovation tradition tradeoff that companies across many industries must routinely face
Full Stark control of polariton states on a spin-orbit hypersphere
The orbital angular momentum and the polarization of light are physical quantities widely investigated for classical and quantum information processing. In this work we propose to take advantage of strong light-matter coupling, circular-symmetric confinement, and transverse-electric transverse-magnetic splitting to exploit states where these two degrees of freedom are combined. To this end we develop a model based on a spin-orbit Poincaré hypersphere. Then we consider the example of semiconductor polariton systems and demonstrate full ultrafast Stark control of spin-orbit states. Moreover, by controlling states on three different spin-orbit spheres and switching from one sphere to another we demonstrate the control of different logic bits within one single physical system
Nanodot-Cavity Electrodynamics and Photon Entanglement
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
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
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Balancing Valued Tradition With Innovation
Successful companies frequently face the challenge of updating a beloved old product. Italian opera companies face this dilemma every season. Many of the best-loved operas in the repertoire are more than 100 years old. The most devoted operagoers will have seen multiple productions of the same work and have a very clear, and usually conservative, notion of what constitutes a proper production. However, making no changes would limit opera’s contemporary cultural relevance. After interviewing 15 artistic directors of Italian opera houses and studying the ticket sales of 2,627 opera productions between 1989 and 2011, we found that the most successful opera houses strategically balance alterations to core and peripheral features of traditional operas across different customer segments. In so doing, they address the need for renewal while at the same time remaining sensitive to the heterogeneity of their audience. The findings offer several actionable insights for successfully navigating the innovation tradition tradeoff that companies across many industries must routinely face
Distensibility index of inferior vena cava diameter in ventilated septic and trauma patients with shock
Flood risk management in Italy: challenges and opportunities for the implementation of the EU Floods Directive (2007/60/EC)
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
Optimal generation of indistinguishable photons from non-identical artificial molecules
We show theoretically that nearly indistinguishable photons can be generated
with non-identical semiconductor-based sources. The use of virtual Raman
transitions and the optimization of the external driving fields increases the
tolerance to spectral inhomogeneity to the meV energy range. A trade-off
emerges between photon indistinguishability and efficiency in the
photon-generation process. Linear (quadratic) dependence of the coincidence
probability within the Hong-Ou-Mandel setup is found with respect to the
dephasing (relaxation) rate in the semiconductor sources
Polariton Pattern Formation and Photon Statistics of the Associated Emission
We report on the formation of a diverse family of transverse spatial polygon patterns in a microcavity
polariton fluid under coherent driving by a blue-detuned pump. Patterns emerge spontaneously
as a result of energy-degenerate polariton-polariton scattering from the pump state to interfering
high order vortex and antivortex modes, breaking azimuthal symmetry. The interplay between a
multimode parametric instability and intrinsic optical bistability leads to a sharp spike in the value
of second order coherence g (2)(0) of the emitted light, which we attribute to the strongly superlinear
kinetics of the underlying scattering processes driving the formation of patterns. We show numerically
by means of a linear stability analysis how the growth of parametric instabilities in our system
can lead to spontaneous symmetry breaking, predicting the formation and competition of different
pattern states in good agreement with experimental observations
Multicomponent polariton superfluidity in the optical parametric oscillator regime
Superfluidity, the ability of a liquid or gas to flow with zero viscosity, is one of the most remarkable
implications of collective quantum coherence. In equilibrium systems like liquid 4He and ultracold
atomic gases, superfluid behaviour conjugates diverse yet related phenomena, such as persistency
of metastable flow in multiply connected geometries and the existence of a critical velocity for
frictionless flow when hitting a static defect. The link between these different aspects of superfluid
behaviour is far less clear in driven-dissipative systems displaying collective coherence, such as
microcavity polaritons, which raises important questions about their concurrency. With a joint
theoretical and experimental study, we show that the scenario is particularly rich for polaritons
driven in a three-fluid collective coherent regime so-called optical parametric oscillator. On the one
hand, the spontaneous macroscopic coherence following the phase locking of the signal and idler
fluids has been shown to be responsible for their simultaneous quantized flow metastability. On the
other hand, we show here that pump, signal and idler have distinct responses when hitting a static
defect; while the signal displays hardly appreciable modulations, the ones appearing in pump and
idler are determined by their mutual coupling due to nonlinear and parametric processes
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