Electrically injected cavity polaritons

We have realised a semiconductor quantum structure that produces electroluminescence while operating in the light-matter strong coupling regime. The mid-infrared light emitting device is composed of a quantum cascade structure embedded in a planar microcavity, based on the GaAs/AlGaAs material system. At zero bias, the structure is characterised using reflectivity measurements which show, up to room temperature, a wide polariton anticrossing between an intersubband transition and the resonant cavity photon mode. Under electrical injection the spectral features of the emitted light change drastically, as electrons are resonantly injected in a reduced part of the polariton branches. Our experiment demonstrates that electrons can be selectively injected into polariton states up to room temperature.Comment: 10 pages, 4 figure

KM3NeT:a large underwater neutrino telescope in the Mediterranean Sea

High energy neutrinos produced in astrophysical processes will allow for a new way of studying the universe. In order to detect the expected flux of high energy neutrinos from specific astrophysical sources, neutrino telescopes of a scale of a km^3 of water will be needed. A Northern Hemisphere detector is being proposed to be sited in a deep area of the Mediterranean Sea. This detector will provide complimentary sky coverage to the IceCube detector being built at the South Pole. The three neutrino telescope projects in the Mediterranean (ANTARES, NEMO and NESTOR) are partners in an effort to design, and build such a km^3 size neutrino telescope, the KM3NeT. The EU is funding a 3-year Design Study; the status of the Design Study is presented and some technical issues are discussed.Comment: 4 pages, 3 figures, Prepared for the 10th International Conference on Astroparticle and Underground Physics (TAUP 2007), Sendai, Japan, 11-15 Sep 200

Sensitivity and spectral control of network lasers

Recently, random lasing in complex networks has shown efficient lasing over more than 50 localised modes, promoted by multiple scattering over the underlying graph. If controlled, these network lasers can lead to fast-switching multifunctional light sources with synthesised spectrum. Here, we observe both in experiment and theory high sensitivity of the network laser spectrum to the spatial shape of the pump profile, with some modes for example increasing in intensity by 280% when switching off 7% of the pump beam. We solve the nonlinear equations within the steady state ab-initio laser theory (SALT) approximation over a graph and we show selective lasing of around 90% of the strongest intensity modes, effectively programming the spectrum of the lasing networks. In our experiments with polymer networks, this high sensitivity enables control of the lasing spectrum through non-uniform pump patterns. We propose the underlying complexity of the network modes as the key element behind efficient spectral control opening the way for the development of optical devices with wide impact for on-chip photonics for communication, sensing, and computation

Deploy Energy-efficient Technologies in the Restoration of a Traditional Building in the Historical Center of Catania (Italy)☆

Abstract The policy about energy efficiency of buildings, including minimum energy requirements and energy performance certificate (EPC), have to be also applied to existing buildings in the case of energy retrofit. In this paper, the possible strategies that can be used to reduce the energy needs of traditional massive buildings, that are widespread in the old town of the Mediterranean cities, have been investigated. To this aim, this study evaluates the energy consumption of a massive building placed in Catania city, called "La Casa del Portuale", which was recently refurbished with the aim to host two local administrative centers. The energy needs of this building was evaluated through computer simulation both in the heating and cooling period, on a yearly basis. The activities research were developed analyzing different refurbishment solutions suitable to improve the thermal performance of most traditional buildings without adversely affecting their fabric and character. Therefore, the feasibility comparison has been performed between the examined refurbishment solutions. The results of the proposed research, considering the diffusion of this typology of buildings, could be assumed as reference to a significant portion of the traditional real estate

Strong enhancement of extremely energetic proton production in central heavy ion collisions at intermediate energy

The energetic proton emission has been investigated as a function of the reaction centrality for the system 58Ni + 58Ni at 30A MeV. Extremely energetic protons (EpNN > 130 MeV) were measured and their multiplicity is found to increase almost quadratically with the number of participant nucleons thus indicating the onset of a mechanism beyond one and two-body dynamics.Comment: 5 pages, 2 figures, submitted to Physical Review Letter

Assessing the feasibility of augmenting fall detection systems by relying on UWB-based position tracking and a home robot

Falls in the home environment are a primary cause of injury in older adults. According to the U.S. Centers for Disease Control and Prevention, every year, one in four adults 65 years of age and older reports experiencing a fall. A variety of different technologies have been proposed to detect fall events. However, the need to detect all fall instances (i.e., to avoid false negatives) has led to the development of systems marked by high sensitivity and hence a significant number of false alarms. The occurrence of false alarms causes frequent and unnecessary calls to emergency response centers, which are critical resources that should be utilized only when necessary. Besides, false alarms decrease the level of confidence of end-users in the fall detection system with a negative impact on their compliance with using the system (e.g., wearing the sensor enabling the detection of fall events). Herein, we present a novel approach aimed to augment traditional fall detection systems that rely on wearable sensors and fall detection algorithms. The proposed approach utilizes a UWB-based tracking system and a home robot. When the fall detection system generates an alarm, the alarm is relayed to a base station that utilizes a UWB-based tracking system to identify where the older adult and the robot are so as to enable navigating the environment using the robot and reaching the older adult to check if he/she experienced a fall. This approach prevents unnecessary calls to emergency response centers while enabling a tele-presence using the robot when appropriate. In this paper, we report the results of a novel fall detection algorithm, the characteristics of the alarm notification system, and the accuracy of the UWB-based tracking system that we implemented. The fall detection algorithm displayed a sensitivity of 99.0% and a specificity of 97.8%. The alarm notification system relayed all simulated alarm notification instances with a maximum delay of 106 ms. The UWB-based tracking system was found to be suitable to locate radio tags both in line-of-sight and in no-line-of-sight conditions. This result was obtained by using a machine learning-based algorithm that we developed to detect and compensate for the multipath effect in no-line-of-sight conditions. When using this algorithm, the error affecting the estimated position of the radio tags was smaller than 0.2 m, which is satisfactory for the application at hand

X-ray emitting structures in the Vela SNR: Ejecta anisotropies and progenitor stellar wind residuals

Context. The Vela supernova remnant (SNR) shows several ejecta fragments (or shrapnel) protruding beyond the forward shock, which are most likely relics of anisotropies that developed during the supernova (SN) explosion. Recent studies have revealed high Si abundance in two shrapnel (shrapnel A and G), located in opposite directions with respect to the SNR center. This suggests the possible existence of a Si-rich jet-counterjet structure, similar to that observed in the SNR Cassiopea A. Aims. We analyzed an XMM-Newton observation of a bright clump, behind shrapnel G, which lies along the direction connecting shrapnel A and G. The aim is to study the physical and chemical properties of this clump to ascertain whether it is part of this putative jet-like structure. Methods. We produced background-corrected and adaptively-smoothed count-rate images and median photon energy maps, and performed a spatially resolved spectral analysis. Results. We identified two structures with different physical properties. The first one is remarkably elongated along the direction connecting shrapnel A and G. Its X-ray spectrum is much softer than that of the other two shrapnel, to the point of hindering the determination of the Si abundance; however, its physical and chemical properties are consistent with those of shrapnel A and shrapnel G. The second structure, running along the southeast-northwest direction, has a higher temperature and appears similar to a thin filament. By analyzing the ROSAT data, we have found that this filament is part of a very large and coherent structure that we identified in the western rim of the shell. Conclusions. We obtained a thorough description of the collimated, jet-like tail of shrapnel G in Vela SNR. In addition we discovered a coherent and very extended feature roughly perpendicular to the jet-like structure that we interpret as a signature of an earlier interaction of the remnant with the stellar wind of its progenitor star. The peculiar Ne/O ratio we found in the wind residual may be suggestive of a Wolf-Rayet progenitor for Vela SNR, though further analysis is required to address this point

Contemporary presence of dynamical and statistical production of intermediate mass fragments in midperipheral 58^{58}Ni+58^{58}Ni collisions at 30 MeV/nucleon

The $^{58}Ni+^{58}Ni$ reaction at 30 MeV/nucleon has been experimentally investigated at the Superconducting Cyclotron of the INFN Laboratori Nazionali del Sud. In midperipheral collisions the production of massive fragments (4$\le$Z$\le$12), consistent with the statistical fragmentation of the projectile-like residue and the dynamical formation of a neck, joining projectile-like and target-like residues, has been observed. The fragments coming from these different processes differ both in charge distribution and isotopic composition. In particular it is shown that these mechanisms leading to fragment production act contemporarily inside the same event.Comment: 9 pages, minor correction

Dye Stabilization and Wavelength Tunability in Lasing Fibers Based on DNA

Lasers based on biological materials are attracting an increasing interest in view of their use in integrated and transient photonics. Deoxyribonucleic acid (DNA) as optical biopolymer in combination with highly emissive dyes has been reported to have excellent potential in this respect. However, achieving miniaturized lasing systems based on solid-state DNA shaped in different geometries to confine and enhance emission is still a challenge, and the physicochemical mechanisms originating fluorescence enhancement are not fully understood. Herein, a class of wavelength-tunable lasers based on DNA nanofibers is demonstrated, for which optical properties are highly controlled through the system morphology. A synergistic effect is highlighted at the basis of lasing action. Through a quantum chemical investigation, it is shown that the interaction of DNA with the encapsulated dye leads to hindered twisting and suppressed channels for the nonradiative decay. This is combined with effective waveguiding, optical gain, and tailored mode confinement to promote morphologically controlled lasing in DNA-based nanofibers. The results establish design rules for the development of bright and tunable nanolasers and optical networks based on DNA nanostructures

Blastic plasmacytoid dendritic cell neoplasm: Genomics mark epigenetic dysregulation as a primary therapeutic target

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematologic malignancy for which there is still no effective B therapy. In order to identify genetic alterations useful for a new treatment design, we used whole-exome sequencing to analyze 14 BPDCN patients and the patient-derived CAL-1 cell line. The functional enrichment analysis of mutational data reported the epigenetic regulatory program to be the most significantly undermined (P<0.0001). In particular, twenty-five epigenetic modifiers were found mutated (e.g. ASXL1, TET2, SUZ12, ARID1A, PHF2, CHD8); ASXL1 was the most frequently affected (28.6% of cases). To evaluate the impact of the identified epigenetic mutations at the gene-expression and Histone H3 lysine 27 trimethylation/acetylation levels, we performed additional RNA and pathology tissue-chromatin immunoprecipitation sequencing experiments. The patients displayed enrichment in gene signatures regulated by methylation and modifiable by decitabine administration, shared common H3K27-acetylated regions, and had a set of cell-cycle genes aberrantly up-regulated and marked by promoter acetylation. Collectively, the integration of sequencing data showed the potential of a therapy based on epigenetic agents. Through the adoption of a preclinical BPDCN mouse model, established by CAL-1 cell line xenografting, we demonstrated the efficacy of the combination of the epigenetic drugs 5’-azacytidine and decitabine in controlling disease progression in vivo