1,969 research outputs found

    Long and short term changes in abundance and distribution of butterflies: hints from the Lazio database

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    The DB on the occurrence data of the butterflies (Papilionoidea) of Lazio, at 14th February 2022 consisted of 36244 records including 154 species istributed throughout a total of 6719 sites. The data set included geoeferenced and chrono-referenced data collected from the literature, specialist-validated occurrences from websites (Forum Natura Mediterraneo, iNaturalist, Ornitho), as well as an important amount of original observations included in the database of the Lazio Biodiversity Observatory. All observations were used to create distribution maps. In order to evaluate any change in observations over time for the various species, all records were divided into three different periods: before 1980 (4425 records), 1980-2000 (6498 records) and post 2000 (25321 records). A finer subdivision was then examined within the post-2000 period: 2001-2007 (11888 records), 2008-2014 (4977 records), 2014-2021 (8456 records). Further analyses were carried out to highlight differences in the distribution of species as a function of altitude and / or changes in land use that have occurred in the last decades. The results show that qualitatively the species present in the region before 1980 are all still present today, however the abundance of related observations in several cases has changed considerably. Observations of an important portion of the species have significantly decreased in recent years. This trend is observed in the majority of mountain species and various habitat-specialist butterflies regardless of altitude. In some other species, often the most common or habitat-generalist butterflies, an increase was observed. The causes of these trends can be identified in the human land use and climate change, without excluding, however, the differences in data recording over time that could favor the most common species

    Mathematical Structure of Rabi Oscillations in the Strong Coupling Regime

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    In this paper we generalize the Jaynes--Cummings Hamiltonian by making use of some operators based on Lie algebras su(1,1) and su(2), and study a mathematical structure of Rabi floppings of these models in the strong coupling regime. We show that Rabi frequencies are given by matrix elements of generalized coherent operators (quant--ph/0202081) under the rotating--wave approximation. In the first half we make a general review of coherent operators and generalized coherent ones based on Lie algebras su(1,1) and su(2). In the latter half we carry out a detailed examination of Frasca (quant--ph/0111134) and generalize his method, and moreover present some related problems. We also apply our results to the construction of controlled unitary gates in Quantum Computation. Lastly we make a brief comment on application to Holonomic Quantum Computation.Comment: Latex file, 24 pages. I added a new section (Quantum Computation), so this paper became self-contained in a certain sens

    Chow's theorem and universal holonomic quantum computation

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    A theorem from control theory relating the Lie algebra generated by vector fields on a manifold to the controllability of the dynamical system is shown to apply to Holonomic Quantum Computation. Conditions for deriving the holonomy algebra are presented by taking covariant derivatives of the curvature associated to a non-Abelian gauge connection. When applied to the Optical Holonomic Computer, these conditions determine that the holonomy group of the two-qubit interaction model contains SU(2)Ă—SU(2)SU(2) \times SU(2). In particular, a universal two-qubit logic gate is attainable for this model.Comment: 13 page

    ASTRI SST-2M prototype and mini-array simulation chain, data reduction software, and archive in the framework of the Cherenkov Telescope Array

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    The Cherenkov Telescope Array (CTA) is a worldwide project aimed at building the next-generation ground-based gamma-ray observatory. Within the CTA project, the Italian National Institute for Astrophysics (INAF) is developing an end-to-end prototype of the CTA Small-Size Telescopes with a dual-mirror (SST-2M) Schwarzschild-Couder configuration. The prototype, named ASTRI SST-2M, is located at the INAF "M.C. Fracastoro" observing station in Serra La Nave (Mt. Etna, Sicily) and is currently in the scientific and performance validation phase. A mini-array of (at least) nine ASTRI telescopes has been then proposed to be deployed at the Southern CTA site, by means of a collaborative effort carried out by institutes from Italy, Brazil, and South-Africa. The CTA/ASTRI team is developing an end-to-end software package for the reduction of the raw data acquired with both ASTRI SST-2M prototype and mini-array, with the aim of actively contributing to the global ongoing activities for the official data handling system of the CTA observatory. The group is also undertaking a massive Monte Carlo simulation data production using the detector Monte Carlo software adopted by the CTA consortium. Simulated data are being used to validate the simulation chain and evaluate the ASTRI SST-2M prototype and mini-array performance. Both activities are also carried out in the framework of the European H2020-ASTERICS (Astronomy ESFRI and Research Infrastructure Cluster) project. A data archiving system, for both ASTRI SST-2M prototype and mini-array, has been also developed by the CTA/ASTRI team, as a testbed for the scientific archive of CTA. In this contribution, we present the main components of the ASTRI data handling systems and report the status of their development.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017), Bexco, Busan, Korea. All CTA contributions at arXiv:1709.0348

    Anisotropic in-plane optical conductivity in detwinned Ba(Fe1-xCox)2As2

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    We study the anisotropic in-plane optical conductivity of detwinned Ba(Fe1-xCox)2As2 single crystals for x=0, 2.5% and 4.5% in a broad energy range (3 meV-5 eV) across their structural and magnetic transitions. For temperatures below the Neel transition, the topology of the reconstructed Fermi surface, combined with the distinct behavior of the scattering rates, determines the anisotropy of the low frequency optical response. For the itinerant charge carriers, we are able to disentangle the evolution of the Drude weights and scattering rates and to observe their enhancement along the orthorhombic antiferromagnetic a-axis with respect to the ferromagnetic b-axis. For temperatures above Ts, uniaxial stress leads to a finite in-plane anisotropy. The anisotropy of the optical conductivity, leading to a significant dichroism, extends to high frequencies in the mid- and near-infrared regions. The temperature dependence of the dichroism at all dopings scales with the anisotropy ratio of the dc conductivity, suggesting the electronic nature of the structural transition. Our findings bear testimony to a large nematic susceptibility that couples very effectively to the uniaxial lattice strain. In order to clarify the subtle interplay of magnetism and Fermi surface topology we compare our results with theoretical calculations obtained from density functional theory within the full-potential linear augmented plane-wave method.Comment: 17 pages, 9 figure

    Infrared signatures of charge stripes in La(2-x)Sr(x)CuO(4)

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    The in-plane optical conductivity of seven La(2-x)Sr(x)CuO(4) single crystals with x between 0 and 0.15 has been studied from 30 to 295 K. All doped samples exhibit strong peaks in the far-infrared, which closely resemble those observed in Cu-O "ladders" with one-dimensional charge-ordering. The behavior with doping and temperature of the peak energy, width, and intensity allows us to conclude that we are observing charge stripes dynamics in La(2-x)Sr(x)CuO(4) on the fast time scale of infrared spectroscopy.Comment: 9 pages including figs. in pdf forma

    Magnetic resonance imaging for deep infiltrating endometriosis: current concepts, imaging technique and key findings

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    Endometriosis is an estrogen-dependent chronic disease affecting about 10% of reproductive-age women with symptoms like pelvic pain and infertility. Pathologically, it is defined by the presence of endometrial tissue outside the uterine cavity responsible for a chronic inflammatory process. For decades the diagnosis of endometriosis was based on surgical exploration and biopsy of pelvic lesions. However, laparoscopy is not a risk-free procedure with possible false negative diagnosis due to an underestimate of retroperitoneal structures such as ureters and nerves. For these reasons nowadays, the diagnosis of endometriosis is based on a noninvasive approach where clinical history, response to therapy and imaging play a fundamental role. Trans-vaginal ultrasound and magnetic resonance imaging are suitable for recognizing most of endometriotic lesions; nevertheless, their accuracy is strictly determined by operators’ experience and imaging technique. This review paper aims to make radiologists aware of the diagnostic possibilities of pelvic MRI and familial with the MR acquisition protocols and image interpretation for women with endometriosis

    In vitro biosafety profile evaluation of multipotent mesenchymal stem cells derived from the bone marrow of sarcoma patients.

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    BACKGROUND: In osteosarcoma (OS) and most Ewing sarcoma (EWS) patients, the primary tumor originates in the bone. Although tumor resection surgery is commonly used to treat these diseases, it frequently leaves massive bone defects that are particularly difficult to be treated. Due to the therapeutic potential of mesenchymal stem cells (MSCs), OS and EWS patients could benefit from an autologous MSCs-based bone reconstruction. However, safety concerns regarding the in vitro expansion of bone marrow-derived MSCs have been raised. To investigate the possible oncogenic potential of MSCs from OS or EWS patients (MSC-SAR) after expansion, this study focused on a biosafety assessment of MSC-SAR obtained after short- and long-term cultivation compared with MSCs from healthy donors (MSC-CTRL). METHODS: We initially characterized the morphology, immunophenotype, and differentiation multipotency of isolated MSC-SAR. MSC-SAR and MSC-CTRL were subsequently expanded under identical culture conditions. Cells at the early (P3/P4) and late (P10) passages were collected for the in vitro analyses including: the sequencing of genes frequently mutated in OS and EWS, evaluation of telomerase activity, assessment of the gene expression profile and activity of major cancer pathways, cytogenetic analysis on synchronous MSC, and molecular karyotyping using a comparative genomic hybridization (CGH) array. RESULTS: MSC-SAR displayed comparable morphology, immunophenotype, proliferation rate, differentiation potential, and telomerase activity to MSC-CTRL. Both cell types displayed signs of senescence in the late stages of culture with no relevant changes in cancer gene expression. However, cytogenetic analysis detected chromosomal anomalies in the early and late stages of MSC-SAR and MSC-CTRL after culture. CONCLUSIONS: Our results demonstrated that the in vitro expansion of MSC does not influence or favor malignant transformation since MSC-SAR were not more prone than MSC-CTRL to deleterious changes during culture. However, the presence of chromosomal aberrations supports rigorous phenotypic, functional and genetic evaluation of the biosafety of MSCs, which is important for clinical applications
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