9,652 research outputs found

    Deterministic Plug-and-Play for Quantum Communication

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    We present a scheme for secure deterministic quantum communication without using entanglement, in a Plug-and-Play fashion. The protocol is completely deterministic, both in the encoding procedure and in the control one, thus doubling the communication rate with respect to other setups; moreover, deterministic nature of transmission, apart from rendering unnecessary bases revelation on the public channel, allows the realization of protocols like `direct communication' and `quantum dialogue'. The encoding exploits the phase degree of freedom of a photon, thus paving the way to an optical fiber implementation, feasible with present day technology.Comment: 4 pages, 2 figures; one reference update

    Quantum dynamics of a high-finesse optical cavity coupled with a thin semi-transparent membrane

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    We study the quantum dynamics of the cavity optomechanical system formed by a Fabry-Perot cavity with a thin vibrating membrane at its center. We first derive the general multimode Hamiltonian describing the radiation pressure interaction between the cavity modes and the vibrational modes of the membrane. We then restrict the analysis to the standard case of a single cavity mode interacting with a single mechanical resonator and we determine to what extent optical absorption by the membrane hinder reaching a quantum regime for the cavity-membrane system. We show that membrane absorption does not pose serious limitations and that one can simultaneously achieve ground state cooling of a vibrational mode of the membrane and stationary optomechanical entanglement with state-of-the-art apparatuses.Comment: 14 pages, 7 figure

    Sensitivity-bandwidth limit in a multi-mode opto-electro-mechanical transducer

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    An opto--electro--mechanical system formed by a nanomembrane capacitively coupled to an LC resonator and to an optical interferometer has been recently employed for the high--sensitive optical readout of radio frequency (RF) signals [T. Bagci, \emph{et~al.}, Nature {\bf 507}, 81 (2013)]. Here we propose and experimentally demonstrate how the bandwidth of such kind of transducer can be increased by controlling the interference between two--electromechanical interaction pathways of a two--mode mechanical system. With a proof--of--principle device \new{operating at room temperature, we achieve a sensitivity of 300 nV/Hz^(1/2) over a bandwidth of 15 kHz in the presence of radiofrequency noise, and an optimal shot-noise limited sensitivity of 10 nV/Hz^(1/2) over a bandwidth of 5 kHz. We discuss strategies for improving the performance of the device, showing that, for the same given sensitivity, a mechanical multi--mode transducer can achieve a bandwidth} significantly larger than that of a single-mode one

    Contralateral prophylactic mastectomies. Correlations between primary tumor and histological findings of controlateral breast

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    Backgound: In Italy in 2015 48,000 new cases of breast carcinomas were diagnosed. Women who are diagnosed with breast cancer have a significant risk of developing contralateral breast cancer during the rest of their lives and this risk is closely associated to the family history, to the onset of breast cancer at a young age and is expressed at about 0.5 to 1% of metachronous tumors per year. The purpose of this work was to evaluate which and how many neoplastic lesions were seen in the contralateral breast that underwent prophylactic mastectomy and to understand what factors predict the appearance of such lesions. Methods: 168 bilateral mastectomies were analyzed in patients with an average age of 47 years, carried out from July 2008 to April 2016, at the Breast Unit of the Sant’Andrea Hospital. We considered women of any age suffering from unilateral breast cancer without either clinical or radiological evidence of a malignant lesion in the contralateral breast and negative for mutations of the BRCA1-BRCA2 genes test. Of the 168 bilateral mastectomies 35 patients were excluded from the study because they underwent neoadjuvant chemotherapy, another 35 patients because they were suffering from a bilateral neoplasia and 7 cases because they had mutated BRCA1 or BRCA2 genes. Therefore the remaining 91 patients were included in the study. Results: Both the histological features of the primary tumor and any lesions found in the contralateral prophylactic breast were analyzed. Histological examination of the main breast showed 59 cases of Invasive Ductal Carcinoma (IDC), 17 cases of Invasive Lobular Carcinoma (ILC), 9 cases of In Situ Ductal Carcinoma (ISDC), 3 microinvasive ductal, 1 invasive tubular carcinoma, 1 in situ lobular and 1 widespread in situ. In the contralateral breast, the definitive histological examination revealed that 47 patients had an occult lesion in the prophylactic contralateral breast; in particular 2 cases of LIN 1, 7 cases of LIN2, 6 cases of lobular carcinoma in situ, 26 between DIN1A/DIN1A-B/DIN1B, 4 cases of carcinoma in situ and 2 cases of Invasive Ductal Carcinoma. The correlation obtained from the observation of the main tumor has shown that in a total of 59 invasive ductal carcinoma 32 have a controlateral occult lesions and in a total of 17 cases of invasive lobular carcinoma 9 have an occult lesion in the prophylactic breast. Of these lesions, the multicentric relationship is that 50% of invasive ductal and invasive lobular carcinoma of the main breast have a contralateral lesion. Conclusion: In conclusion we would like to remind, as demonstrated by our follow-up data and as the literature reiterates, that this surgery does not improve patient survival. Certainly patients with unilateral breast cancer have many surgical therapies to be able to deal with not only having a bilateral mastectomy. The end point of this work is try to understand the risk factors of having a contralateral breast lesion to reduce the probability of a metachronous cance

    Polimorfismi biochimici nel sangue e nel latte della capra sarda

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    The Authors, in a study on 990 individual samples of blood and milk collected from Sardinian goats, have found the presence of polymorphism at the loci Hb, Tf, X protein, β- Lg, αs-Cn, while the loci Alb, CA, SOD, α-La, β-Cn were monomorphic

    Proximity Constraints and Representable Trees

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    Use of peas in organic buffalo farming: effects on nutrient digestibility and milk production

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    Twenty lactating buffalo cows, organically farmed, were used to examine the effects of including peas in total mixed ration. Two concentrates were formulated to contain, as the main protein sources, either 350 g/kg of soybean cake (CC) or 450 g/kg of peas (ExpC). Cows were blocked into two groups according to parity and previous milk yield and were assigned to one of two dietary treatments: one group was fed a diet with 6 kg/d of CC, whereas the treatment group was fed diet in which 3kg/d of CC were replaced by an equal quantity of ExpC. Digestibility of the diets and milk production of the cows were measured. The experimental period covered the whole lactation period. No differences were observed between groups for milk yield and composition, and for total tract apparent digestibility. The main hypothesis tested, that the replacement of soybean cake with peas in buffalo diet would not affect milk yield and composition, was confirmed. This suggested that the partial substitution of soybean cake with peas in diet for buffalo cows can be possible without affect performances

    Testosterone insulin-like effects: an in vitro study on the short-term metabolic effects of testosterone in human skeletal muscle cells

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    Testosterone by promoting different metabolic pathways contributes to short-term homeostasis of skeletal muscle, the largest insulin-sensitive tissue and the primary site for insulin-stimulated glucose utilization. Despite evidences indicate a close relationship between testosterone and glucose metabolism, the molecular mechanisms responsible for a possible testosterone-mediated insulin-like effects on skeletal muscle are still unknown
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