335 research outputs found

    Persistent Localized Broadcasting in VANETs

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    We present a communication protocol, called LINGER, for persistent dissemination of delay-tolerant information to vehicular users, within a geographical area of interest. The goal of LINGER is to dispatch and confine information in localized areas of a mobile network with minimal protocol overhead and without requiring knowledge of the vehicles' routes or destinations. LINGER does not require roadside infrastructure support: it selects mobile nodes in a distributed, cooperative way and lets them act as "information bearers", providing uninterrupted information availability within a desired region. We analyze the performance of our dissemination mechanism through extensive simulations, in complex vehicular scenarios with realistic node mobility. The results demonstrate that LINGER represents a viable, appealing alternative to infrastructure-based solutions, as it can successfully drive the information toward a region of interest from a far away source and keep it local with negligible overhead. We show the effectiveness of such an approach in the support of localized broadcasting, in terms of both percentage of informed vehicles and information delivery delay, and we compare its performance to that of a dedicated, state-of-the-art protoco

    Automation in urinalysis: evaluation of three urine test strip analysers

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    A clinical laboratory evaluation was conducted on the Clinitek Auto 2000, the Super Aution Analyzer and the Urotron RL9 for the determination of glucose, protein, pH, blood, ketone-bodies and bilirubin

    Three-dimensional assessment of nose and lip morphology in North Sudanese subjects with Down syndrome

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    Objective: To detail the nasolabial morphologic characteristics of North Sudanese subjects with Down syndrome (DS). Materials and Methods: Nasolabial morphology was assessed three-dimensionally in 64 North Sudanese subjects with DS aged 4 to 34 years and in 682 sex- and age-matched controls. Three-dimensional facial coordinates were collected using a laser scan, and selected distances, angles, areas, and volumes were computed. Subject and reference data were compared by computing z-scores and Student's t-tests. Results: The nose was significantly smaller (area) in subjects with DS than in reference subjects, and it had a different shape (more flat angle of alar slope, more acute nasal tip angle). The vertical (nasal bridge length, nose height) and anteroposterior (nasal tip protrusion) dimensions were reduced, while the horizontal dimensions (alar base width, inferior widths of the nostrils) were increased. The nasolabial angle was increased. The cutaneous lip volume was significantly smaller, while the vermilion lip area was larger in the subjects with DS. The mouth and philtrum widths were significantly reduced, while the vermilion height was significantly increased. Conclusion: Analyzed subjects with DS had a hypoplastic nose and different upper and lower lips than did reference, normal subjects. (Angle Orthod. 2011;81:107-114.

    Vacuum Alignment in SUSY A4 Models

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    In this note we discuss the vacuum alignment in supersymmetric models with spontaneously broken flavour symmetries in the presence of soft supersymmetry (SUSY) breaking terms. We show that the inclusion of soft SUSY breaking terms can give rise to non-vanishing vacuum expectation values (VEVs) for the auxiliary components of the flavon fields. These non-zero VEVs can have an important impact on the phenomenology of this class of models, since they can induce an additional flavour violating contribution to the sfermion soft mass matrix of right-left (RL) type. We carry out an explicit computation in a class of SUSY A4 models predicting tri-bimaximal mixing in the lepton sector. The flavour symmetry breaking sector is described in terms of flavon and driving supermultiplets. We find non-vanishing VEVs for the auxiliary components of the flavon fields and for the scalar components of the driving fields which are of order m_{SUSY} x and m_{SUSY}, respectively. Thereby, m_{SUSY} is the generic soft SUSY breaking scale which is expected to be around 1 TeV and is the VEV of scalar components of the flavon fields. Another effect of these VEVs can be the generation of a mu term.Comment: 23 pages; added a new section on the relation to Supergravity; version accepted for publication in JHE

    A SUSY SU(5) Grand Unified Model of Tri-Bimaximal Mixing from A4

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    We discuss a grand unified model based on SUSY SU(5) in extra dimensions and on the flavour group A4xU(1) which, besides reproducing tri-bimaximal mixing for neutrinos with the accuracy required by the data, also leads to a natural description of the observed pattern of quark masses and mixings.Comment: 19 page

    Equivalent effective Lagrangians for Scherk-Schwarz compactifications

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    We discuss the general form of the mass terms that can appear in the effective field theories of coordinate-dependent compactifications a la Scherk-Schwarz. As an illustrative example, we consider an interacting five-dimensional theory compactified on the orbifold S^1/Z_2, with a fermion subject to twisted periodicity conditions. We show how the same physics can be described by equivalent effective Lagrangians for periodic fields, related by field redefinitions and differing only in the form of the five-dimensional mass terms. In a suitable limit, these mass terms can be localized at the orbifold fixed points. We also show how to reconstruct the twist parameter from any given mass terms of the allowed form. Finally, after mentioning some possible generalizations of our results, we re-discuss the example of brane-induced supersymmetry breaking in five-dimensional Poincare' supergravity, and comment on its relation with gaugino condensation in M-theory.Comment: 17 pages, 3 figures. Published versio

    Isolation, absolute configuration and cytotoxic activities of alkaloids from Hippeastrum goianum (Ravenna) Meerow (Amaryllidaceae)

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    The phytochemical study of Hippeastrum goianum led to the identification of 13 compounds by means of gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). Compounds 7-demethoxy-9-O-methylhostasine (1) and 7-deoxi-trans-dihydronarciclasine (2) had their absolute configurations determined by vibrational circular dichroism (VCD). This is the first time that compound 1 is described in the Amaryllidaceae family. The cytotoxicity of all isolated compounds was tested against colorectal carcinoma (HCT 116), breast carcinoma (MCF-7), and non-tumor human retinal pigment epithelium (RPE) cell lines. The half-maximum inhibitory concentration (IC50) of compound 2 against each cell line was equivalent to the positive control (doxorubicin), indicating a considerable cytotoxic activity. Keywords: narciclasine; galasine; cytotoxic activity; absolute configuration; vibrational circular dichrois

    The K2K SciBar Detector

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    A new near detector, SciBar, for the K2K long-baseline neutrino oscillation expe riment was installed to improve the measurement of neutrino energy spectrum and to study neutrino interactions in the energy region around 1 GeV. SciBar is a 'fully active' tracking detector with fine segmentation consisting of plastic scintillator bars. The detector was constructed in summer 2003 and is taking data since October 2003. The basic design and initial performance is presented.Comment: 7 pages, 4figures, Contributed to Proceedings of the 10th Vienna Conference on Instrumentation, Vienna, February 16-21, 200

    The Golden Ratio Prediction for the Solar Angle from a Natural Model with A5 Flavour Symmetry

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    We formulate a consistent model predicting, in the leading order approximation, maximal atmospheric mixing angle, vanishing reactor angle and tan {\theta}_12 = 1/{\phi} where {\phi} is the Golden Ratio. The model is based on the flavour symmetry A5 \times Z5 \times Z3, spontaneously broken by a set of flavon fields. By minimizing the scalar potential of the theory up to the next-to-leading order in the symmetry breaking parameter, we demonstrate that this mixing pattern is naturally achieved in a finite portion of the parameter space, through the vacuum alignment of the flavon fields. The leading order approximation is stable against higher-order corrections. We also compare our construction to other models based on discrete symmetry groups.Comment: 28 pages, 2 figures. Minor changes, references added. Corrected typos in Appendix A. Version appeared on JHE

    The expression of platelet serotonin transporter (SERT) in human obesity

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    Serotonin (5-HT) is a well-known modulator of eating behavior. However, the molecular mechanisms linking its action to body weight balance have been only partially elucidated. Since platelets are a suitable peripheral model to study 5-HT transport, metabolism and release, we herein evaluated the expression of the platelet 5-HT re-uptake system (SERT) by [3H]-paroxetine binding assay. A cohort of 114 unrelated individuals (34 males, 80 females; age, mean +/- SD: 38.57 +/- 12.47 years) without major psychiatric disorders, was recruited following a naturalistic design regarding age or gender and classified accordingly to their body mass index (BMI). Subjects were divided into 5 groups: normal-weight (NW), overweight (OW) and grade I-III obese (OB) individuals. For gender analyses, data were transformed into [3H]-paroxetine density (Bmax)/BMI ratios to overcome both the disparity of women vs. men number and anthropometric differences between sexes.[3H]-paroxetine Bmax (SERT density, fmol/mg proteins) was reduced in platelet membranes of grade II (p < 0.01) and III (p < 0.001) obese subjects vs. controls and in overweight subjects (p < 0.05) vs. grade III obese individuals. Considering all patients together, a strong negative correlation between Bmax and BMI (r = -0.449; P < 0.0001) was demonstrated. Conversely, [3H]-paroxetine KD (dissociation constant, nM) did not differ among groups. No gender-related variation concerning Bmax/BMI ratios was observed in this cohort of subjects.The down-regulation of SERT in platelet membranes of severe human obesity (BMI > 35 Kg/m2) confirms the involvement of 5-HT system in body weight gain. Moreover, this findings may help to elucidate those monoamine-endocrine networks acting on fat storage, adipocyte signaling and energy balance. Targeting 5-HT/5-HT-related markers will possibly uncover the existence of human obesity subtypes
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