Impact of along-valley orographic variations on the dispersion of passive tracers in a stable atmosphere

© 2019 by the authors.A numerical model is used to investigate the transport of passive tracers in an idealized Alpine valley during stable wintertime conditions after the evening transition. The valley is composed of an upstream-valley section, which opens on a narrower downstream valley section, which opens onto a plain. The ratio between the valley-floor widths of the upstream and downstream sections is either 4 (simulation P1) or 11.5 (P2). The change in the thermal structure of the atmosphere in the along-valley direction and over the plain leads to the development of an along-valley flow. This flow is up-valley in the upstream section during the first three hours of the P1 simulation, reversing to the down-valley direction afterwards, but remains up-valley during the six hours of the P2 simulation. The effect of wind dynamics on the dispersion of passive scalars is identified by tracking areas prone to stagnation, recirculation, and ventilation using the methodology developed by Allwine and Whiteman (1994). Zones identified as prone to stagnation are consistent with those of high tracer concentration in both simulations. The narrowing of the valley is found to significantly reduce ventilation in the upstream section, an observation quantified by a ventilation efficiency.Peer reviewedFinal Published versio

Gauge dependence of calculations in relativistic Coulomb excitation

Before a quantum-mechanical calculation involving electromagnetic interactions is performed, a choice must be made of the gauge to be used in expressing the potentials. If the calculation is done exactly, the observable results it predicts will be independent of the choice of gauge. However, in most practical calculations approximations are made, which can destroy the gauge invariance of the predictions. We compare here the results of coupled-channel time-dependent relativistic Coulomb excitation calculations, as performed in either Lorentz or Coulomb gauges. We find significant differences when the bombarding energy per nucleon is $\geq$ 2 GeV, which indicates that the common practice of relying completely on the Lorentz gauge can be dangerous.Comment: 23 pages, 3 figure

Forecasting inflation in a macroeconomic framework: An application to Tunisia

The aim of this paper is to demonstrate the relative performance of combining forecasts on inflation in the case of Tunisia. For that, we use a large number of econometric models to forecast short-run inflation. Specifically, we use univariate models as Random Walk, SARIMA, a Time Varying Parameter model and a suite of multivariate autoregressive models as Bayesian VAR and Dynamic Factor models. Results of forecasting suggest that models which incorporate more economic information outperform the benchmark random walk for the first two quarters ahead. Furthermore, we combine our forecasts by means and the finding results reveal that the forecast combination leads to a reduction in forecast error compared to individual models

Coulomb Excitation of Multi-Phonon Levels of the Giant Dipole Resonance

A closed expression is obtained for the cross-section for Coulomb excitation of levels of the giant dipole resonance of given angular momentum and phonon number. Applications are made to the Goldhaber-Teller and Steinwedel-Jensen descriptions of the resonance, at non-relativistic and relativistic bombarding energies.Comment: 16 pages, 5 figure

Studi Evaluatif Implementasi E-training di Pusat Pengembangan Pendidikan Anak Usia Dini Nonformal dan Informal Regional I Bandung.

Penelitian ini berkenaan dengan kualitas implementasi e-training di Pusat Pengembangan Pendidikan Anak Usia Dini Nonformal dan Informal Regional I Bandung. Penelitian ini menggunakan model evaluasi CIPP (in, input, process, product) dari Stufflebeam. Teknik pengumpulan data menggunakan instrumen kuesioner/angket, wawancara, dan studi dokumentasi. Responden penelitian adalah Guru PAUD yang berasal dari Kecamatan Cibadak, Kabupaten Sukabumi dan telah mengikuti diklat dasar berbasis e-training. Kesimpulan yang dapat diambil adalah 1) kualitas implementasi e-training pada komponen context yaitu baik. 2) kualitas implementasi e-training pada komponen input yaitu baik. 3) kualitas implementasi e-training pada komponen process yaitu baik. 4) kualitas implementasi e-training pada komponen product yaitu baik. Rekomendasi penelitian ini adalah 1) optimalisasi proses training needs analysis pada saat merencanakan sebuah program. 2) Resouces planning e-training pada komponen input juga harus diperhatikan. 3) sistem kontrol project management ditingkatkan optimalisasinya. 4) Return on investment dalam e-training kedepannya harus dibangun sehingga dampak e-training bisa terlihat sampai sejauh mana.----------This study deals with the quality of the implementation of e-training at the Center for Early Childhood Development Education Non-Formal and Informal Regional I Bandung. This study uses the CIPP evaluation model (in, inputs, process, product) of Stufflebeam. Data collection technique used questionnaire / questionnaire, interview, and documentation. Respondents are derived from early childhood teacher Cibadak subdistrict, Sukabumi and had undergone basic training-based e-training. The conclusions are: 1) the quality of the implementation of e-training in the context component that is good. 2) the quality of the implementation of e-training on the input component that is good. 3) the quality of the implementation of e-training component that is a good process. 4) the quality of the implementation of e-training component that is a good product. Recommendations of this study were 1) to optimize the process of training needs analysis when planning a program. 2) Resouces planning e-training on the input components must also be considered. 3) improved project management control system optimalisasinya. 4) Return on investment in e-training in the future must be built so that the impact of e-training can be seen to what extent

Biogeographical patterns of endolithic infestation in an invasive and an indigenous intertidal marine ecosystem engineer

By altering the phenotypic properties of their hosts, endolithic parasites can modulate the engineering processes of marine ecosystem engineers. Here, we assessed the biogeographical patterns of species assemblages, prevalence and impact of endolithic parasitism in two mussel species that act as important ecosystem engineers in the southern African intertidal habitat, Perna perna and Mytilus galloprovincialis. We conducted large-scale surveys across three biogeographic regions along the South African coast: the subtropical east coast, dominated by the indigenous mussel, P. perna, the warm temperate south coast, where this species coexists with the invasive Mediterranean mussel, M. galloprovincialis, and the cool temperate west coast dominated by M. galloprovincialis. Infestation increased with mussel size, and in the case of M. galloprovincialis we found a significantly higher infestation in the cool temperate bioregion than the warm temperate region. For P. perna, the prevalence of infestation was higher on the warm temperate than the subtropical region, though the difference was marginally non-significant. On the south coast, there was no significant difference in infestation prevalence between species. Endolith-induced mortality rates through shell collapse mirrored the patterns for prevalence. For P. perna, endolith species assemblages revealed clear grouping by bioregions. Our findings indicate that biogeography affects cyanobacteria species composition, but differences between biogeographic regions in their effects are driven by environmental conditions.Agência financiadora Número do subsídio Fundacao para a Ciencia e Tecnologia (FCT-MEC, Portugal) UID/Multi/04326/2019 IF/01413/2014/CP1217/CT0004 South African Research Chairs Initiative (SARChI) of the Department of Science and Technology National Research Foundationinfo:eu-repo/semantics/publishedVersio

Quantum derivation of the use of classical electromagnetic potentials in relativistic Coulomb excitation

We prove that a relativistic Coulomb excitation calculation in which the classical electromagnetic field of the projectile is used to induce transitions between target states gives the same target transition amplitudes, to all orders of perturbation theory, as would a calculation in which the interaction between projectile and target is mediated by a quantized electromagnetic field.Comment: 1 .zip file containing LaTex source plus three figures as .eps file

Equivalence of the long-wavelength approximation and the truncated Taylor expansion in relativistic Coulomb excitation

The long-wavelength approximation and the truncated Taylor expansion are frequently used in the theory of relativistic Coulomb excitation to obtain multipole expansions of the interaction. It is shown in this note that these two approximations are exactly equivalent.Comment: 5 page