Quantum Backaction on kg-Scale Mirrors: Observation of Radiation Pressure Noise in the Advanced Virgo Detector.

The quantum radiation pressure and the quantum shot noise in laser-interferometric gravitational wave detectors constitute a macroscopic manifestation of the Heisenberg inequality. If quantum shot noise can be easily observed, the observation of quantum radiation pressure noise has been elusive, so far, due to the technical noise competing with quantum effects. Here, we discuss the evidence of quantum radiation pressure noise in the Advanced Virgo gravitational wave detector. In our experiment, we inject squeezed vacuum states of light into the interferometer in order to manipulate the quantum backaction on the 42 kg mirrors and observe the corresponding quantum noise driven displacement at frequencies between 30 and 70 Hz. The experimental data, obtained in various interferometer configurations, is tested against the Advanced Virgo detector quantum noise model which confirmed the measured magnitude of quantum radiation pressure noise.

Increasing the Astrophysical Reach of the Advanced Virgo Detector via the Application of Squeezed Vacuum States of Light.

Current interferometric gravitational-wave detectors are limited by quantum noise over a wide range of their measurement bandwidth. One method to overcome the quantum limit is the injection of squeezed vacuum states of light into the interferometer's dark port. Here, we report on the successful application of this quantum technology to improve the shot noise limited sensitivity of the Advanced Virgo gravitational-wave detector. A sensitivity enhancement of up to 3.2±0.1 dB beyond the shot noise limit is achieved. This nonclassical improvement corresponds to a 5%-8% increase of the binary neutron star horizon. The squeezing injection was fully automated and over the first 5 months of the third joint LIGO-Virgo observation run O3 squeezing was applied for more than 99% of the science time. During this period several gravitational-wave candidates have been recorded.

Observation of superconducting vortex clusters in S/F hybrids.

While Abrikosov vortices repel each other and form a uniform vortex lattice in bulk type-II superconductors, strong confinement potential profoundly affects their spatial distribution eventually leading to vortex cluster formation. The confinement could be induced by the geometric boundaries in mesoscopic-size superconductors or by the spatial modulation of the magnetic field in superconductor/ferromagnet (S/F) hybrids. Here we study the vortex confinement in S/F thin film heterostructures and we observe that vortex clusters appear near magnetization inhomogeneities in the ferromagnet, called bifurcations. We use magnetic force microscopy to image magnetic bifurcations and superconducting vortices, while high resolution scanning tunneling microscopy is used to obtain detailed information of the local electronic density of states outside and inside the vortex cluster. We find an intervortex spacing at the bifurcation shorter than the one predicted for the same superconductor in a uniform magnetic field equal to the thermodynamical upper critical field Hc2. This result is due to a local enhanced stray field and a competition between vortex-vortex repulsion and Lorentz force. Our findings suggest that special magnetic topologies could result in S/F hybrids that support superconductivity even when locally the vortex density exceeds the thermodynamic critical threshold value beyond which the superconductivity is destroyed.

Ferromagnetism and Conductivity in Hydrogen Irradiated Co-Doped ZnO Thin Films.

Impressive changes in the transport and ferromagnetic properties of Co-doped ZnO thin films have been obtained by postgrowth hydrogen irradiation at temperatures of 400 °C. Hydrogen incorporation increases the saturation magnetization by one order of magnitude (up to ∼1.50 µB/Co) and increases the carrier density and mobility by about a factor of two. In addition to the magnetic characterization, the transport and structural properties of hydrogenated ZnO:Co have been investigated by Hall effect, local probe conductivity measurements, micro-Raman, and X-ray absorption spectroscopy. Particular care has been given to the detection of Co oxides and metal Co nanophases, whose influence on the increase in the transport and ferromagnetic properties can be excluded on the ground of the achieved results. The enhancement in ferromagnetism is directly related to the dose of H introduced in the samples. On the contrary, despite the shallow donor character of H atoms, the increase in carrier density n is not related to the H dose. These apparently contradictory effects of H are fully accounted for by a mechanism based on a theoretical model involving Co-VO (Co-O vacancy) pairs.

A comparative study of the responses of lithium borate and calcium sulphate phosphors in a TL personal dosemeter.

This work summarises the results of a series of experiences made on Panasonic UD-802AS, a multi-element dosemeter that is currently used in Caorso Nuclear Power Plant for personnel external monitoring. Two main topics have been considered: energy response and the influence of working place dose rate on relative readings of the elements at the end of the monitoring period. The presence of four elements of different materials and filtrations gives the possibility of evaluating radiation energy by a simple algorithm, so that an accurate estimate of the personal dose equivalent can be provided; the good results of the participation of Caorso Individual Monitoring Service (IMS) to 'EURADOS 2008 intercomparison on whole-body dosemeters' account for the reliability of the method. A study on the response in low-dose rate fields is also reported, giving in practice interesting information about operational conditions.

A tunneling spectroscopy study of the pairing symmetry in the electron-doped Pr(1-x)LaCe(x)CuO(4-y).

We have performed scanning tunneling spectroscopy and point contact spectroscopy measurements on the electron-doped superconductor Pr(1-x)LaCe(x)CuO(4-y) (x = 0.12, T(c) is approximately equal 25 K). We address the question of the symmetry of the order parameter and of the amplitude of the energy gap. We compare three possible scenarios, i.e. isotropic s-wave, 'anisotropic' s-wave, and d-wave. Evidence for a d-wave symmetry of the order parameter is given. From the temperature evolution of the dI/dV versus V characteristics we extract a BCS-like temperature dependence of the superconducting energy gap Δ. Despite the variety of measured spectra we give a consistent explanation for the whole set of data, indicating Δ = (3.6 ± 0.2) meV and a ratio 2Δ/K(B)T(C) is approximately equal 3.5 ±0.2. In particular, point contact characteristics showing gap-like features at higher voltages have been interpreted by considering the formation of an intergrain Josephson junction in series with the point contact junction. Further confirmation of the correctness of the model is given by the behavior of the critical current of the intergrain Josephson junction versus temperature which follows the Ambegaokar-Baratoff behavior.

Structural, electrical and magnetic characterization of artificial ferromagnetic/superconducting (La(0.7)Ca(0.3)MnO(3)/YBa(2)Cu(3)O(7-x)) heterostructures.

The fabrication and characterization of superconducting and ferromagnetic heterostructures is an open field due to the fundamental interest in the physics of the coexistence of these two competing orders and their possible applications in the spintronics industry. In this paper we present structural, electrical and magnetic characterization for the single La(0.7)Ca(0.3)MnO(3) (LCMO) thin layer, La(0.7)Ca(0.3)MnO(3)/YBa(2)Cu(3)O(7-x) (LCMO/YBCO) bilayers and the LCMO/YBCO/LCMO trilayers. In particular, we show a detailed magnetic characterization of the LCMO thin films by means of low temperature magnetic force microscopy. We discuss the different dynamics of the magnetic domains observed, depending on the substrate induced strain and on the film thickness.

[Mitochondrial disease and complete heart block. Kearns-Sayre syndrome. Description of a case]. / Malattie mitocondriali e blocco cardiaco completo. Sindrome di Kearns-Sayre. Descrizione di un caso.

Defects of the mitochondrial respiratory chain form a clinically and biochemically heterogeneous group of diseases. Mitochondrial diseases include myopathies and multisystem disorders that are defined either by biochemical abnormalities of the mitochondria or by the presence of "ragged red fibers" in muscle-biopsy specimens stained with modified Gomori's trichrome stain. Several syndromes have been identified. Typical Kearns-Sayre syndrome is a sporadic condition that is characterized by an onset before the age of 20, progressive external ophthalmoplegia, pigmentary retinopathy and cardiac disorders. Mitochondrial DNA deletions were found in patient with Kearns-Sayre syndrome. We report the case of a 33 year-old woman, with neuromuscular syndrome of the Kearns-Sayre type, insulin-sensitive diabetes and complete heart block, who was implanted a pacemaker.

[Primary malignant lymphoma of the heart. Description of a case and review of the literature]. / Linfoma maligno primitivo del cuore. Descrizione di un caso e revisione della letteratura.

Primary cardiac tumors are rare. Approximately 25% of primary cardiac tumors are malignant, with the majority of these being sarcomas. Primary lymphoma of the heart is a very rare malignancy, usually recognized at autopsy or fatal within a few weeks of diagnosis. we report the case of a patient with diffuse large uncleaved cell lymphoma of the heart who had dyspnea, distention of the neck veins, edema of the face and arms. The diagnosis in this patient was aided by 2D-echocardiography, CT scan of the chest and superior vena caval angiography. The diagnosis was confirmed at operation and by histological examination. Surgical procedures were only palliative and aimed at prolonging life. However, prognosis remained severe and unchanged.

[A left atrial myxoma. The clinical aspects]. / Mixoma atriale sinistro. Considerazioni cliniche.

The paper describes a case of left atrial myxoma, which was unidentified for many years after the onset of symptoms, with emphasis on the necessity for instrumental investigations (particularly M-mode and two-dimensional echocardiography) in order to obtain an accurate and prompt diagnosis of these affections when the patient's clinical history justifies the suspicion.

[Syncopal attacks caused by paroxysmal atrioventricular block in patients with systemic lupus erythematosus]. / Crisi sincopali da blocco atrio ventricolare parossistico in pazienti con lupus eritematoso sistemico.

The case is described of a young woman with SLE and lipothymic and syncopal attacks during second degree paroxysmal AVB or low frequency junctional rhythm. The case was cured by the implantation of a permanent multi-programmable pace-maker.

[Considerations on myocardial scintigraphy with 201thallium after stress]. / Considerazioni sulla scintigrafia miocardica con 201tallio dopo sforzo.

An heterogeneous group of 12 patients has been studied with 201thallium myocardial scintigraphy after stress (MSS); has been used an electronic calculator which made it possible to increase the reliability of the method. Eight patients were males, 4 females; the average age were 52.6 years. The 201thallium (1.7-2 mCi) is injected (through a Teflon cannula inserted in the forearm) 1' before the interruption of the stress test on the cycloergometer. After 10' tests are made in AP-LAO and LL view; a second test is carried out after an hour, and, if necessary, after 4-6 hours time. The results are interpreted as: a) positive: absence (++) or obvious defect in perfusion (+); b) negative: normal perfusion (-); c) questionable: activity not significantly reduced (+/-). In some cases, the authors studied correlations and discordances between MSS and clinical, coronarographic and echocardiographic data. It has been considered moreover, the uptake's and release's variations of the radio-isotope in relation with experimental knowledge of myocardial extraction and clearance. We conclude by emphasizing the interest of this method and suggesting some practical considerations: 1) Patients with negative MSS don't need coronarography. 2) Positive MSS, but restricted deficit, good delayed reperfusion, good clinical pharmacological control would permit a delay of coronarography. 3) Clear multiple deficit need coronarography. 4) Usefulness of the MSS for long-term control of the evolution of coronary disease and of patients operated of aortocoronary bypass.

[Considerations on myocardial scintigraphy with 201thallium after stress (author's transl)]. / Considerazioni sulla scintigrafia miocardica con 201tallio dopo sforzo.

An heterogeneous group of 24 patients has been studied with 201Thallium myocardial scintigraphy after stress (MSS); has been used an electronic calculator which made it possible to increase the reliability of the method. Nineteen patients were males, 5 females; the average age were 51.7 years S.D. = +/- 7.9. The 201Thallium (2 mCi) is iniected through a Teflon cannula inserted in the forearm l' before the interruption of the stress test on the cycloergometer. After 10' tests are made in AP-LAO and LL view; a second test is carried out after an hour, and, if necessary, after 4-6 hours time. The results are interpreted as: a) positive: absence (++) or obvious defect in perfusione (+); b) negative: normal perfusion (-); c) questionable: activity not significantly reduced (+/-). In some cases, the Authors studied correlations and discordances between MSS and clinical, coronarographic and echocardiographic data. Has been considered moreover, the uptake's and release's variations of the radio-isotope in relation with experimental knowledge of myocardial extration and clearance. We conclude by emphasising the interest of this method and suggesting some practical consideration: 1) patients with negative MSS don't need coronarography; 2) positive MSS, but restricted deficit, good delayed reperfusion, good clinical pharmacological control would permit a delay of coronarography. 3) clear multiple deficit need coronarography; 4) usefulness of the MSS for long-term control of the evolution of coronary disease and of patients operated of aorto-coronary bypass.

Myocardial uptake of radiotechnetium in two cases of ventricular aneurysm after infarction.

Two very similar cases of persistent positive myocardial scintigraphy with radiotechnetium are described and, in view of agreement of other medical, electrocardiographic, apexcardiographic and radiographic data, this can be ascribed to the presence of a parietal ventricular aneurysm after myocardial infarction.

[Isoproterenol test in the diagnosis of coronary insufficiency]. / Il test all'isoproterenolo nella diagnosi di insufficienza coronarica

Coronary performance was evaluated in 18 men and 6 women by i.v. infusion of increasing doses of isoproterenol and minute-by-minute ECG monitoring. The results appeared fully reliable. In some cases where the conditions for effort testing were satisfied a comparison was made with the cycle-ergometer findings. This shown the ISP test to be more precise, more sensitive and easier to perform technically.