1,260 research outputs found

    Charm and longitudinal structure functions with the Kharzeev-Levin-Nardi model

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    We use the Kharzeev-Levin-Nardi model of the low xx gluon distributions to fit recent HERA data on charm and longitudinal structure functions. Having checked that this model gives a good description of the data, we use it to predict F2cF^c_2 and FLF_L to be measured in a future electron-ion collider. The results interpolate between those obtained with the de Florian-Sassot and Eskola-Paukkunen-Salgado nuclear gluon distributions. The conclusion of this exercise is that the KLN model, simple as it is, may still be used as an auxiliary tool to make estimates both for heavy ion and electron-ion collisions.Comment: 6 pages, 7 figure

    Nucleon Tensor Charge from Exclusive πo\pi^o Electroproduction

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    Exclusive πo\pi^o electroproduction from nucleons is suggested for extracting the tensor charge and other quantities related to transversity from experimental data. This process isolates C-parity odd and chiral odd combinations of t-channel exchange quantum numbers. In a hadronic picture it connects the meson production amplitudes to C-odd Regge exchanges with final state interactions. In a description based on partonic degrees of freedom, the helicity structure for this C-odd process relates to the quark helicity flip, or chiral odd generalized parton distributions. This differs markedly from deeply virtual Compton scattering, and both vector meson and charged π\pi electroproduction, where the axial charge can enter the amplitudes. Contrarily the tensor charge enters the πo\pi^o process. The connection through the helicity description of the process to both the partonic and hadronic perspectives is studied and exploited in model calculations to indicate how the tensor charge and other transversity parameters can be related to cross section and spin asymmetry measurements over a broad range of kinematics.Comment: 40 pages, 14 figures Revised text clarifying main points, fixing typos, adding reference

    The Art academy without walls: photography in context.

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    A photographic workshop for the Art Academy Without Walls, Lusaka, Zambia 2004. A NORAD (Norwegian Government Aid Organisation) commissioned project to generate a photographic facility for the Zambian Visual Arts Community, carry out technical inductions, deliver daily thematic lectures and discussions, supervise thematic workshops, set up a public exhibition. Agree on a management strategy for the facility and write a report

    Bounds on R-parity Violation from Resonant Slepton Production at the LHC

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    We consider the ATLAS and CMS searches for dijet resonances, as well as the ATLAS search for like-sign dimuon pairs at the LHC with 7 TeV center of mass energy. We interpret their exclusions in terms of bounds on the supersymmetric R-parity violating parameter space. For this we focus on resonant slepton production followed by the corresponding decay.Comment: 17 pages, 11 figures, 3 table

    Infra-Red Plasmonic Sensors

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    Plasmonic sensors exploiting the localized surface plasmon resonance (LSPR) of noble metal nanoparticles are common in the visual spectrum. However, bio-sensors near the infra-red (NIR) windows (600–900 nm and 1000–1400 nm) are of interest, as in these regions the absorption coefficients of water, melanin deoxyglobin, and hemoglobin are all low. The first part of this paper reviews the work that has been undertaken using gold (Au) and silver (Ag) particles in metal enhanced fluorescence (MEF) in the NIR. Despite this success, there are limitations, as there is only a narrow band in the visual and NIR where losses are low for traditional plasmonic materials. Further, noble metals are not compatible with standard silicon manufacturing processes, making it challenging to produce on-chip integrated plasmonic sensors with Au or Ag. Therefore, it is desirable to use different materials for plasmonic chemical and biological sensing, that are foundry-compatible with silicon (Si) and germanium (Ge). One material that has received significant attention is highly-doped Ge, which starts to exhibit metallic properties at a wavelength as short as 6 μm. This is discussed in the second part of the paper and the results of recent analysis are included

    Phenomenological description of the gamma* p cross section at low Q2

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    Low Q2 photon-proton cross sections are analysed using a simple, QCD-motivated parametrisation σγ⋆p∝1/(Q2+Q02)\sigma_{\gamma^\star p}\propto 1/(Q^2+Q_0^2), which gives a good description of the data. The Q2 dependence of the gamma* p cross section is discussed in terms of the partonic transverse momenta of the hadronic state the photon fluctuates into.Comment: 14 pages, revtex, epsfig, 2 figure

    On the dbar/ubar Asymmetry and Parton Distributions

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    We discuss the impact of different measurements of the dbar/ubar asymmetry in the extraction of parameterizations of parton distribution functions.Comment: Contributed paper to LP01, 13 pages, 4 figure

    Revolucionando la educación especial del inglés como lengua extranjera: cómo ChatGPT está transformando la forma en que los profesores abordan el aprendizaje de idiomas

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    This mixed-methods study explored the attitudes of 199 English as a Foreign Language (EFL) special education teachers towards using ChatGPT for language learning. The survey questionnaire, consisting of 21 items, examined attitudes, effectiveness, barriers, and the future use of ChatGPT. The results revealed that participants held moderate attitudes, perceiving ChatGPT as moderately effective with moderate barriers. While no significant differences were found between male and female teachers in attitudes and effectiveness, significant gender differences emerged in the future use of ChatGPT, with female teachers exhibiting a greater willingness to embrace it. Follow-up email interviews with five participants provided valuable insights into strategies, effectiveness, challenges, and inclusivity when using ChatGPT in language instruction for special education students. These findings contribute to implementing and developing ChatGPT as a language learning tool for EFL special education students, emphasizing the importance of gender-inclusive approaches and practical considerations to enhance its efficacy.Este estudio de métodos mixtos exploró las actitudes de 199 profesores de educación especial de inglés como lengua extranjera (EFL) hacia el uso de ChatGPT para el aprendizaje del idioma. El cuestionario de encuesta, compuesto por 21 ítems, examinó las actitudes, la efectividad, las barreras y el uso futuro de ChatGPT. Los resultados revelaron que los participantes tenían actitudes moderadas, percibiendo a ChatGPT como moderadamente efectivo con barreras moderadas. Si bien no se encontraron diferencias significativas entre los profesores hombres y mujeres en cuanto a actitudes y efectividad, surgieron diferencias de género significativas en el uso futuro de ChatGPT, siendo las profesoras mujeres las que mostraron una mayor disposición a adoptarlo. Entrevistas de seguimiento por correo electrónico con cinco participantes proporcionaron información valiosa sobre estrategias, efectividad, desafíos e inclusión al usar ChatGPT en la enseñanza del idioma para estudiantes de educación especial. Estos hallazgos contribuyen a implementar y desarrollar ChatGPT como herramienta de aprendizaje de idiomas para estudiantes de educación especial de EFL, enfatizando la importancia de enfoques inclusivos de género y consideraciones prácticas para mejorar su eficacia

    Deep Inelastic Scattering at HERA

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    Results from the H1 and ZEUS experiments at HERA on deep inelastic scattering are reviewed. The data lead to a consistent picture of a steep rise in the F_2 structure function and in the gluon density within the proton. Important new information on the partonic structure of diffraction is emerging from H1 and ZEUS. The space-like region in which the weak and electromagnetic interactions become of equal strength is being explored for the first time. A possible excess of events at high x and Q^2 compared to the expectations of the Standard Model has been observed in both experiments.Comment: 80 pages, 42 figure

    Design of Computer Experiments: a powerful tool for the numerical design of BAW filters

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    We apply Design of Computer Experiments methods to the simulation of piezoelectric stacks and the design of BAW resonators and filters. Through the example of DCS filters with two different technologies (Iridium and Molybdenum electrodes), we show that the definition and the exploitation of a metamodel can accurately replace acoustic simulations and allows therefore a much faster material stack desig
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