1,287 research outputs found

    Crossovers between epigenesis and epigenetics. A multicenter approach to the history of epigenetics (1901-1975)

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    The origin of epigenetics has been traditionally traced back to Conrad Hal Waddington's foundational work in 1940s. The aim of the present paper is to reveal a hidden history of epigenetics, by means of a multicenter approach. Our analysis shows that genetics and embryology in early XX century--far from being non-communicating vessels--shared similar questions, as epitomized by Thomas Hunt Morgan's works. Such questions were rooted in the theory of epigenesis and set the scene for the development of epigenetics. Since the 1950s, the contribution of key scientists (Mary Lyon and Eduardo Scarano), as well as the discussions at the international conference of Gif-sur-Yvette (1957) paved the way for three fundamental shifts of focus: 1. From the whole embryo to the gene; 2. From the gene to the complex extranuclear processes of development; 3. From cytoplasmic inheritance to the epigenetics mechanisms

    Recursive Motion and Structure Estimation with Complete Error Characterization

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    We present an algorithm that perfom recursive estimation of ego-motion andambient structure from a stream of monocular Perspective images of a number of feature points. The algorithm is based on an Extended Kalman Filter (EKF) that integrates over time the instantaneous motion and structure measurements computed by a 2-perspective-views step. Key features of our filter are (I) global observability of the model, (2) complete on-line characterization of the uncertainty of the measurements provided by the two-views step. The filter is thus guaranteed to be well-behaved regardless of the particular motion undergone by the observel: Regions of motion space that do not allow recovery of structure (e.g. pure rotation) may be crossed while maintaining good estimates of structure and motion; whenever reliable measurements are available they are exploited. The algorithm works well for arbitrary motions with minimal smoothness assumptions and no ad hoc tuning. Simulations are presented that illustrate these characteristics

    Secondary metabolites with ecologic and medicinal implications in Anthemis cretica subsp. petraea from Majella National Park

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    Anthemis cretica subsp. petraea (Ten.) Greuter is a plant belonging to the Asteraceae family and endemic of central Italy. In this paper, the first analysisof the ethanolic fraction of samples collected in the Majella National Park is reported. Seven compounds were isolated and identified namely parthenolide (1), 9α-acetoxyparthenolide (2), tamarixetin (3), 7-hydroxycoumarin (4), 4'-hydroxyacetophenone (5), leucanthemitol (conduritol F) (6),and proto-quercitol (7). Isolation of the compounds was achieved by means ofcolumn chromatography (CC), while their identification was achieved through spectroscopic and spectrometric techniques. The presence of these compounds is of great relevance. Compounds 1 and 2 are chemosystematic markers of the family, thus confirming the correct botanical classification of the species. Conversely, compounds 3, 5,and 7 were identified for the first time in the species and, instead, confirm the tendency of endemic entities to develop characteristic metabolite patterns in respect to cosmopolite species. Moreover, the presence of compounds 6 and 7 has ecologic implications and may be linked to this taxon’s adaption to dry environments. The production of these osmolytes may, in fact, represent the reason why this species is able to survive in extreme conditions of aridity. Lastly, from a medicinal standpoint, the isolated compounds are endowed with interesting biological activities and may justify, on a molecular base, the widespread traditional uses of the Anthemis species, as well as a basis for the use ofthe subspecies petraea

    About the use of generalized forms of derivatives in the study of electromagnetic problems

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    The use of non-local operators, defining Riemann–Liouville or Caputo derivatives, is a very useful tool to study problems involving non-conventional diffusion problems. The case of electric circuits, ruled by non-integer derivatives or capacitors with fractional dielectric permittivity, is a fairly natural frame of relevant applications. We use techniques, involving generalized exponential operators, to obtain suitable solutions for this type of problems and eventually discuss specific problems in applications

    From rods to helices: evidence of a screw-like nematic phase

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    Evidence of a special chiral nematic phase is provided using numerical simulation and Onsager theory for systems of hard helical particles. This phase appears at the high density end of the nematic phase, when helices are well aligned, and is characterized by the C2_2 symmetry axes of the helices spiraling around the nematic director with periodicity equal to the particle pitch. This coupling between translational and rotational degrees of freedom allows a more efficient packing and hence an increase of translational entropy. Suitable order parameters and correlation functions are introduced to identify this screw-like phase, whose main features are then studied as a function of radius and pitch of the helical particles. Our study highlights the physical mechanism underlying a similar ordering observed in colloidal helical flagella [E. Barry et al. \textit{Phys. Rev. Lett.} \textbf{96}, 018305 (2006)] and raises the question of whether it could be observed in other helical particle systems, such as DNA, at sufficiently high densities.Comment: List of authors correcte

    IdentitĂ  e relazioni sociali. Dai popoli migranti alla cultura del Web 2.0

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    Nel saggio è una riflessione preliminare su cos'è da intendere per identità prima di individuare il ruolo che svolge la comunicazione non solo nel mantenere ma anche e soprattutto nel costruire identità e nel gestire relazioni, nel senso di crearle, mutarle o annullarle.The essay is a reflection about identity and role of communication on creating, mantaining and destroying social relations

    High-speed data transfer with FPGAs and QSFP+ modules

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    We present test results and characterization of a data transmission system based on a last generation FPGA and a commercial QSFP+ (Quad Small Form Pluggable +) module. QSFP+ standard defines a hot-pluggable transceiver available in copper or optical cable assemblies for an aggregated bandwidth of up to 40 Gbps. We implemented a complete testbench based on a commercial development card mounting an Altera Stratix IV FPGA with 24 serial transceivers at 8.5 Gbps, together with a custom mezzanine hosting three QSFP+ modules. We present test results and signal integrity measurements up to an aggregated bandwidth of 12 Gbps.Comment: 5 pages, 3 figures, Published on JINST Journal of Instrumentation proceedings of Topical Workshop on Electronics for Particle Physics 2010, 20-24 September 2010, Aachen, Germany(R Ammendola et al 2010 JINST 5 C12019


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    Aim. Acinetobacter Baumannii (coming from the Greek “akinetos,” i.e. non-motile) is an opportunistic bacterial pathogen primarily associated with hospital-acquired infections. Commonly associated with aquatic environments, A. Baumannii easily contaminates the surrounding environment and it colonizes acute ill patients in which can survive for several days. Generally, A. Baumannii is able to damage mucous membranes or exposed skin after accident or injury; it may be responsible of many diseases such as pneumonia, bacteremia, meningitis, urinary tract infections, peritonitis and infections of skin and soft tissues. Tissues infected by A. Baumannii initially present “orange peel” appearance followed by sandpaper-like presentation, when there is a disruption, hemorrhagic bullae can be seen with a visible necrotizing process followed by bacteremia. Current therapy is based on intravenous administration of tigecycline 100-200 mg (first dose) and 50-100 mg every 12 h for up to 14 days, unless complications. If untreated, this infection can lead to septicemia and death. The mortality rate of this infection is high, especially in case of bacteremia (52%) and pneumonia (23–73%). A. Baumannii is resistant to many drugs and represents an important nosocomial pathogen that particularly infects critically ill patients. At the best of our knowledge, no case of oral infection has been reported. to present the first one case characterized by oral soft tissue infection due to A. Baumannii responsive to imipenem. Materials and methods. a 78 years male was hospitalized in August of 2013 at the Hematology unit of the A.O.U.P. “P. Giaccone” of Palermo with a diagnosis of autoimmune hemolytic anemia (AIHA). He was treated per os with corticosteroids (Prednisone) and immunosuppressants (Rituximab and Cyclophosphamide), also IVIG (Intra Venous Immuno-Globulin) was administreted. In November 2013, the patient was treated with piperacillin IV (Tazocin) for treating an urinary tract infection; four days after, multiple oral ulcerative bullous lesions on the lingual and buccal mucosa and crusted lesions on the lip vermilion appeared, associated with intense pain. An oral swab for bacteria research was carried out; topical therapy (chlorhexidine rinses and hyaluronic acid gel) has been prescribed and piperacillin therapy was stopped. Oral swab outcome resulted positive for A. Baumannii and Enterococcus Faecalis, both sensitive only to imipenem, that was administrated (500 mg IV every 8h) for 10 days. The patient was immediately isolated in a single room for preventing and controlling the spread of A. Baumannii. Results. From diagnosis, every 3 days clinical examination of the oral cavity was performed, revealing the progressive regression within thirty days until complete healing without leaving scars. After, a second oral swab confirmed the absence of any bacteria. Conclusions. The World Health Organization has recently identified antimicrobial resistance as one of the three most important problems facing human health and among the most common and serious pathogens, including A. Baumannii. It is an emerging potentially drug-resistant micro-organism and its isolation must alert physicians to carry on all preventive measures for avoiding contamination of other patients, especially those immunosuppressed, at risk for severe persistent infections or death. This precaution should be continued for all the duration of hospitalization and until the negativization of culture samples was obtained. It is important that physicians and dentists recognize suspicious lesions in unusual locations, such as oral mucosa, in absence of other known etiological factors in a timely manner before the diffusion among other patients in order to avoid the spread of a nosocomial outbreak
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