1,502 research outputs found
The 5C 6 and 5C 7 surveys of radio sources
5C 6 and 5C 7 continue the series of deep surveys made at 408 and 1407 MHz with the One-Mile telescope at Cambridge. They were intended (1) to provide a sample of faint radio sources suitable for further study; (2) to improve the statistics of source counts N(S) and spectral-index distributions at low flux densities; (3) to study the isotropy of the distribution of faint sources. Each observed field is about 4° in diameter at 408 MHz and 1° in diameter at 1407 MHz, and the field-centres are a α = 02ʰ14ᵐ, δ = 32° (5C 6) and α = 08ᵏ17ᵐ, δ = 27° (5C 7). The synthesized beamwidths (FWHM) are 80 arcsec (408 MHz) and 23 arcsec (1407 MHz). The techniques of observation and data-analysis followed closely those used for 5C 5 (Pearson, T. J., 1975. Mon. Not. R. astr. Soc., 171, 475), with some minor variations which are noted in Section 2
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Educational strategies in data journalism: A comparative study of six European countries
The article explores training programs in higher education with regard to data journalism from a multi-national perspective. By carrying out a comparative analysis in six European countries (Germany, Switzerland, the Netherlands, Italy, Poland, and the United Kingdom), it covers different models of media systems and journalistic cultures envisaged by Hallin and Mancini. Based on a desk review and in-depth interviews with instructors of data journalism in each country, the article identifies different approaches to the way data journalism is taught. In Europe, such programs are offered by four types of organizations: academic, vocational, professional, and civic. The role played by those organizations can be explained as a result of the peculiarities of national media systems. But there are also commonalities, for example, non-academic institutions (such as the European Journalism Center or the Center for Investigative Journalism) and major international news outlets (such as The Guardian and The New York Times) seem to take over a leading role in all of the analyzed countries. Generally speaking, data journalism education appears to be a very young discipline that frequently neglects fundamental journalistic topics such as ethical issues, transparency, accountability, and responsiveness although they are crucial in a journalistic field as sophisticated tools to reveal hidden aspects of reality
The 5C 6 and 5C 7 surveys of radio sources
5C 6 and 5C 7 continue the series of deep surveys made at 408 and 1407 MHz with the One-Mile telescope at Cambridge. They were intended (1) to provide a sample of faint radio sources suitable for further study; (2) to improve the statistics of source counts N(S) and spectral-index distributions at low flux densities; (3) to study the isotropy of the distribution of faint sources. Each observed field is about 4° in diameter at 408 MHz and 1° in diameter at 1407 MHz, and the field-centres are a α = 02ʰ14ᵐ, δ = 32° (5C 6) and α = 08ᵏ17ᵐ, δ = 27° (5C 7). The synthesized beamwidths (FWHM) are 80 arcsec (408 MHz) and 23 arcsec (1407 MHz). The techniques of observation and data-analysis followed closely those used for 5C 5 (Pearson, T. J., 1975. Mon. Not. R. astr. Soc., 171, 475), with some minor variations which are noted in Section 2
Ground state potential energy surfaces and bound states of M-He dimers (M=Cu,Ag,Au): A theoretical investigation
We present an ab initio investigation on the ground state interaction potentials [potential energy surface (PES)] between helium and the group 11 metal atoms: copper, silver, and gold. To the best of our knowledge, there are no previous theoretical PESs proposed for Cu-He and Au-He, and a single one for Ag-He [Z. J. Jakubek and M. Takami, Chem. Phys. Lett. 265, 653 (1997)], computed about 10 years ago at MP2 level and significantly improved by our study. To reach a high degree of accuracy in the determination of the three M-He potentials (M=Cu,Ag,Au), we performed extensive series of test computations to establish the appropriate basis set, the theoretical method, and the computational scheme for these systems. For each M-He dimer we computed the PES at the CCSD(T) level of theory, starting from the reference unrestricted Hartree-Fock wave function. We described the inner shells with relativistic small core pseudopotentials, and we adopted high quality basis sets for the valence electrons. We also performed CCSDT computations in a limited set of M-He internuclear distances, adopting a medium-sized basis set, such as to define for each dimer a CCSD(T) to CCSDT correction term and to improve further the quality of the CCSD(T) interaction potentials. The Cu-He complex has minimum interaction energy (E(min)) of -28.4 mu hartree at the internuclear distance of 4.59 A (R(min)), and the short-range repulsive wall starts at 4.04 A (R(E=0)). Quite interestingly, the PES of Ag-He is more attractive (E(min)=-33.8 mu hartree) but presents nearly the same R(min) and R(E=0) values, 4.60 and 4.04 A, respectively. The interaction potential for Au-He is markedly deeper and shifted at shorter distances as compared to the lighter complexes, with E(min)=-69.6 mu hartree, R(min)=4.09 A and R(E=0)=3.60 A. As a first insight in the structure of M-He(n) aggregates, we determined the rovibrational structure of the three M-He dimers. The Cu-He and Ag-He potentials support just few rotational excitations, while the Au-He PES admits also a bound vibrational excitation
Pola Pertumbuhan Dan Produksi Tanaman Cabai Merah Keriting (Capsicum Annuum L.) Akibat Aplikasi Kalium Nitrat Pada Daerah Dataran Rendah
Cabai (Capsicum annuum L.) merupakan salah satu komoditas hortikultura yang memiliki nilai ekonomi penting di Indonesia, sehingga budidaya cabai sangat menarik bagi petani. Permintaan produk cabai cenderung meningkat terus sehingga dapat diandalkan sebagai komoditas nonmigas. Seiring dengan permintaan yang meningkat sehingga kurangnya pasokan yang tersedia maka peningkatan luas tanam diarahkan untuk mencapai keseimbangan pasokan dan permintaan. Salah satu USAha yang dapat dilakukan adalah melakukan teknik budidaya yang baik dan benar sehingga hasil yang diperoleh optimal. Salah satu aspek yang penting dalam budidaya tanaman adalah pemupukan.Penelitian ini bertujuan untuk mengetahui respon pola pertumbuhan tanaman cabai merah terhadap aplikasi Kalium Nitrat dan untuk mengetahui respon komponen hasil cabai terhadap pemberian Kalium Nitrat dengan konsentrasi berbeda. Penelitian ini dilaksanakan di Desa Sukabanjar Kecamatan Gedong Tataan Kabupaten Pesawaran dari Oktober 2011 sampai April 2012. Penelitian disusun menggunakan Rancangan acak kelompok dengan perlakuan tunggal yaitu konsentrasi KNO3 yang terdiri atas : 0, 2, 4, 6, 8 g l-1, dengan 3 kali ulangan. Seluruh data yang diperoleh dianalisis ragam. Homogenitas ragam diuji dengan uji Bartlett sedangkan aditivitas diuji dengan uji Tukey. Analisis data dilanjutkan dengan uji polinomial ortogonal pada taraf 5%. Hasil penelitian menunjukan bahwa pada pola pertumbuhan vegetatif untuk variabel tinggi tanaman dan tingkat percabangan aplikasi kalium nitrat pada berbagai taraf konsentrasi yaitu : 0, 2, 4, 6, 8 g l-1 tidak memberikan pengaruh yang nyata dan pada pemberian kalium nitrat dengan konsentrasi 4, 6, 8 g l-1 meningkatkan jumlah bunga di tanaman cabai. Peningkatan jumlah buah tertinggi terdapat pada aplikasi kalium nitrat dengan konsentrasi 8 g l-1, sedangkan pada bobot buah total tertinggi terjadi pada konsentrasi 6 g l-1
The nuclear jets in 3C309.1 & 3C380
8 station VLBI maps of the nuclear jets in 3C309.1 and 3C380 reveal complex, bent, structures which seem hard to reconcile with the concept of ballistic outflow. Together with the observation of “flaring” in the MERLIN/EVN map of the 3C309.1 jet the maps point strongly to the jets being confined fluid flows
A progressive diagonalization scheme for the Rabi Hamiltonian
A diagonalization scheme for the Rabi Hamiltonian, which describes a qubit
interacting with a single-mode radiation field via a dipole interaction, is
proposed. It is shown that the Rabi Hamiltonian can be solved almost exactly
using a progressive scheme that involves a finite set of one variable
polynomial equations. The scheme is especially efficient for lower part of the
spectrum. Some low-lying energy levels of the model with several sets of
parameters are calculated and compared to those provided by the recently
proposed generalized rotating-wave approximation and full matrix
diagonalization.Comment: 8pages, 1 figure, LaTeX. Accepted for publication in J. Phys. B: At.
Mol. Opt. Phy
Studies of resistance switching effects in metal/YBa2Cu3O7-x interface junctions
Current-voltage characteristics of planar junctions formed by an epitaxial
c-axis oriented YBa2Cu3O7-x thin film micro-bridge and Ag counter-electrode
were measured in the temperature range from 4.2 K to 300 K. A hysteretic
behavior related to switching of the junction resistance from a high-resistive
to a low-resistive state and vice-versa was observed and analyzed in terms of
the maximal current bias and temperature dependence. The same effects were
observed on a sub-micrometer scale YBa2Cu3O7-x thin film - PtIr point contact
junctions using Scanning Tunneling Microscope. These phenomena are discussed
within a diffusion model, describing an oxygen vacancy drift in YBa2Cu3O7-x
films in the nano-scale vicinity of the junction interface under applied
electrical fields.Comment: To be published in Applied Surface Science
Computational benchmarking for ultrafast electron dynamics: wavefunction methods vs density functional theory
Attosecond electron dynamics in small- and medium-sized molecules, induced by an ultrashort strong optical pulse, is studied computationally for a frozen nuclear geometry. The importance of exchange and correlation effects on the nonequilibrium electron dynamics induced by the interaction of the molecule with the strong optical pulse is analyzed by comparing the solution of the time-dependent Schrodinger equation based on the correlated field-free stationary electronic states computed with the equation-of-motion coupled cluster singles and doubles and the complete active space multi-configurational self-consistent field methodologies on one hand, and various functionals in real-time time-dependent density functional theory (TD-DFT) on the other. We aim to evaluate the performance of the latter approach, which is very widely used for nonlinear absorption processes and whose computational cost has a more favorable scaling with the system size. We focus on LiH as a toy model for a nontrivial molecule and show that our conclusions carry over to larger molecules, exemplified by ABCU (C10H19N). The molecules are probed with IR and UV pulses whose intensities are not strong enough to significantly ionize the system. By comparing the evolution of the time-dependent field-free electronic dipole moment, as well as its Fourier power spectrum, we show that TD-DFT performs qualitatively well in most cases. Contrary to previous studies, we find almost no changes in the TD-DFT excitation energies when excited states are populated. Transitions between states of different symmetries are induced using pulses polarized in different directions. We observe that the performance of TD-DFT does not depend on the symmetry of the states involved in the transition.Belgian Fonds National de la Recherche Collective through project number 2.4545.12 “Control of attosecond dynamics: applications to molecular reactivity
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