521 research outputs found

    Two-pion exchange NN potential from Lorentz-invariant χ\chiEFT

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    We outline the progress made in the past five years by the S\~ao Paulo group in the development of a two-pion exchange nucleon-nucleon potential within a Lorentz-invariant framework of (baryon) chiral perturbation theory.Comment: 5 pages, Talk given at the 18th International IUPAP Conference on Few-Body Problems in Physics, August 21-26 2006, Santos, Sao Paulo, Brazi

    Substance P regulates puberty onset and fertility in the female mouse

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    Puberty is a tightly regulated process that leads to reproductive capacity. Kiss1 neurons are crucial in this process by stimulating GnRH, yet how Kiss1 neurons are regulated remains unknown. Substance P (SP), an important neuropeptide in pain perception, induces gonadotropin release in adult mice in a kisspeptin-dependent manner. Here, we assessed whether SP, through binding to its receptor NK1R (neurokinin 1 receptor), participates in the timing of puberty onset and fertility in the mouse. We observed that 1) selective NK1R agonists induce gonadotropin release in prepubertal females; 2) the expression of Tac1 (encoding SP) and Tacr1 (NK1R) in the arcuate nucleus is maximal before puberty, suggesting increased SP tone; 3) repeated exposure to NK1R agonists prepubertally advances puberty onset; and 4) female Tac1-/- mice display delayed puberty; moreover, 5) SP deficiency leads to subfertility in females, showing fewer corpora lutea and antral follicles and leading to decreased litter size. Thus, our findings support a role for SP in the stimulation of gonadotropins before puberty, acting via Kiss1 neurons to stimulate GnRH release, and its involvement in the attainment of full reproductive capabilities in female mice. Copyright © 2015 by the Endocrine Society

    Disfiguring Annular Sarcoidosis Improved by Adalimumab

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    Depending on the location, dermatoses can produce blemishes that severely impair quality of life and require highly effective treatment that is otherwise used for extensive skin involvement. We report the case of a 39-year-old, otherwise healthy male disfigured by an 8 × 7-cm hypopigmented and centrally atrophic annular plaque with erythematous indurated borders in an area of scar tissue on his forehead. Skin biopsies revealed non-caseating granulomas, and hilar involvement was identified, leading to the diagnosis of systemic sarcoidosis stage II with cutaneous involvement. The lesions proved resistant to multiple therapies, but responded within 4 months to adalimumab with regression of the lesion and inflammatory infiltrate. The visual analogue scale of disease activity decreased from 7/10 to 3.5/10, and the Dermatology Life Quality Index from 16/30 to 3/30 points. In conclusion, TNF-α inhibition can control inflammation and disfigurement by cutaneous sarcoidosis and restore quality of life

    From Predicting Solar Activity to Forecasting Space Weather: Practical Examples of Research-to-Operations and Operations-to-Research

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    The successful transition of research to operations (R2O) and operations to research (O2R) requires, above all, interaction between the two communities. We explore the role that close interaction and ongoing communication played in the successful fielding of three separate developments: an observation platform, a numerical model, and a visualization and specification tool. Additionally, we will examine how these three pieces came together to revolutionize interplanetary coronal mass ejection (ICME) arrival forecasts. A discussion of the importance of education and training in ensuring a positive outcome from R2O activity follows. We describe efforts by the meteorological community to make research results more accessible to forecasters and the applicability of these efforts to the transfer of space-weather research.We end with a forecaster "wish list" for R2O transitions. Ongoing, two-way communication between the research and operations communities is the thread connecting it all.Comment: 18 pages, 3 figures, Solar Physics in pres

    Emotion: Appraisal-coping model for the "Cascades" problem

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    Modelling emotion has become a challenge nowadays. Therefore, several models have been produced in order to express human emotional activity. However, only a few of them are currently able to express the close relationship existing between emotion and cognition. An appraisal-coping model is presented here, with the aim to simulate the emotional impact caused by the evaluation of a particular situation (appraisal), along with the consequent cognitive reaction intended to face the situation (coping). This model is applied to the "Cascades" problem, a small arithmetical exercise designed for ten-year-old pupils. The goal is to create a model corresponding to a child's behaviour when solving the problem using his own strategies.Comment: 6 page

    Light transport in cold atoms: the fate of coherent backscattering in the weak localization regime

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    The recent observation of coherent backscattering (CBS) of light by atoms has emphasized the key role of the velocity spread and of the quantum internal structure of the atoms. Firstly, using highly resonant scatterers imposes very low temperatures of the disordered medium in order to keep the full contrast of the CBS interference. This criterion is usually achieved with standard laser cooling techniques. Secondly, a non trivial internal atomic structure leads to a dramatic decrease of the CBS contrast. Experiments with Rubidium atoms (with a non trivial internal structure) and with Strontium (with the simplest possible internal structure) show this behaviour and confirm theoretical calculations

    Cluster Masses Accounting for Structure along the Line of Sight

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    Weak gravitational lensing of background galaxies by foreground clusters offers an excellent opportunity to measure cluster masses directly without using gas as a probe. One source of noise which seems difficult to avoid is large scale structure along the line of sight. Here I show that, by using standard map-making techniques, one can minimize the deleterious effects of this noise. The resulting uncertainties on cluster masses are significantly smaller than when large scale structure is not properly accounted for, although still larger than if it was absent altogether.Comment: 5 pages, 5 figure

    Photo- and Electron-Production of Mesons on Nucleons and Nuclei

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    In these lectures I will show some results obtained with the chiral unitary approach applied to the photo and electroproduction of mesons. The results for photoproduction of ηπ0p\eta \pi^0 p and K0π0Σ+K^0 \pi^0 \Sigma^+, together with related reactions will be shown, having with common denominator the excitation of the Δ(1700)\Delta(1700) resonance which is one of those dynamically generated in the chiral unitary approach. Then I will show results obtained for the e+eϕf0(980)e^+ e^- \to \phi f_0(980) reaction which reproduce the bulk of the data except for a pronounced peak, giving support to a new mesonic resonance, X(2175). Results will also be shown for the electromagnetic form factors of the N(1535)N^*(1535) resonance, also dynamically generated in this approach. Finally, I will show some results on the photoproduction of the ω\omega in nuclei, showing that present experimental results claiming a shift of the ω\omega mass in the medium are tied to a particular choice of background and are not conclusive. One the other hand, the same experimental results show unambiguously a huge increase of the ω\omega width in the nuclear medium.Comment: Lecture at the "International School of Nuclear Physics", 29th Course Quarks in Hadrons and Nuclei, Erice, Italy, September 2007. Note added in Proofs concerning the mixed events technique and other comments on omega productio

    Parity Violation in Proton-Proton Scattering

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    Measurements of parity-violating longitudinal analyzing powers (normalized asymmetries) in polarized proton-proton scattering provide a unique window on the interplay between the weak and strong interactions between and within hadrons. Several new proton-proton parity violation experiments are presently either being performed or are being prepared for execution in the near future: at TRIUMF at 221 MeV and 450 MeV and at COSY (Kernforschungsanlage Juelich) at 230 MeV and near 1.3 GeV. These experiments are intended to provide stringent constraints on the set of six effective weak meson-nucleon coupling constants, which characterize the weak interaction between hadrons in the energy domain where meson exchange models provide an appropriate description. The 221 MeV is unique in that it selects a single transition amplitude (3P2-1D2) and consequently constrains the weak meson-nucleon coupling constant h_rho{pp}. The TRIUMF 221 MeV proton-proton parity violation experiment is described in some detail. A preliminary result for the longitudinal analyzing power is Az = (1.1 +/-0.4 +/-0.4) x 10^-7. Further proton-proton parity violation experiments are commented on. The anomaly at 6 GeV/c requires that a new multi-GeV proton-proton parity violation experiment be performed.Comment: 13 Pages LaTeX, 5 PostScript figures, uses espcrc1.sty. Invited talk at QULEN97, International Conference on Quark Lepton Nuclear Physics -- Nonperturbative QCD Hadron Physics & Electroweak Nuclear Processes --, Osaka, Japan May 20--23, 199
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