Temporal characterization of the requests to Wikipedia

This paper presents an empirical study about the temporal patterns characterizing the requests submitted by users to Wikipedia. The study is based on the analysis of the log lines registered by the Wikimedia Foundation Squid servers after having sent the appropriate content in response to users' requests. The analysis has been conducted regarding the ten most visited editions of Wikipedia and has involved more than 14,000 million log lines corresponding to the traffic of the entire year 2009. The conducted methodology has mainly consisted in the parsing and filtering of users' requests according to the study directives. As a result, relevant information fields have been finally stored in a database for persistence and further characterization. In this way, we, first, assessed, whether the traffic to Wikipedia could serve as a reliable estimator of the overall traffic to all the Wikimedia Foundation projects. Our subsequent analysis of the temporal evolutions corresponding to the different types of requests to Wikipedia revealed interesting differences and similarities among them that can be related to the users' attention to the Encyclopedia. In addition, we have performed separated characterizations of each Wikipedia edition to compare their respective evolutions over time

A quantitative examination of the impact of featured articles in Wikipedia

This paper presents a quantitative examination of the impact of the presentation of featured articles as quality content in the main page of several Wikipedia editions. Moreover, the paper also presents the analysis performed to determine the number of visits received by the articles promoted to the featured status. We have analyzed the visits not only in the month when articles awarded the promotion or were included in the main page, but also in the previous and following ones. The main aim for this is to assess the attention attracted by the featured content and the different dynamics exhibited by each community of users in respect to the promotion process. The main results of this paper are twofold: it shows how to extract relevant information related to the use of Wikipedia, which is an emerging research topic, and it analyzes whether the featured articles mechanism achieve to attract more attention

Correlation between magnetic interactions and domain structure in A1 FePt ferromagnetic thin films

We have investigated the relationship between the domain structure and the magnetic interactions in a series of FePt ferromagnetic thin films of varying thickness. As-made films grow in the magnetically soft and chemically disordered A1 phase that may have two distinct domain structures. Above a critical thickness $d_{cr}\sim 30$ nm the presence of an out of plane anisotropy induces the formation of stripes, while for $d<d_{cr}$ planar domains occur. Magnetic interactions have been characterized using the well known DCD-IRM remanence protocols, $\delta M$ plots, and magnetic viscosity measurements. We have observed a strong correlation between the domain configuration and the sign of the magnetic interactions. Planar domains are associated with positive exchange-like interactions, while stripe domains have a strong negative dipolar-like contribution. In this last case we have found a close correlation between the interaction parameter and the surface dipolar energy of the stripe domain structure. Using time dependent magnetic viscosity measurements, we have also estimated an average activation volume for magnetic reversal, $\langle V_{ac}\rangle \sim 1.37\times 10^{4}$ nm$^{3},$ which is approximately independent of the film thickness or the stripe period.Comment: 25 pages, 11 figure

Characterization of the Wikipedia Traffic

Since its inception, Wikipedia has grown to a solid and stable project and turned into a mass collaboration tool that allows the sharing and distribution of knowledge. The wiki approach that basis this initiative promotes the participation and collaboration of users. In addition to visits for browsing its contents, Wikipedia also receives the contributions of users to improve them. In the past, researchers paid attention to different aspects concerning authoring and quality of contents. However, little effort has been made to study the nature of the visits that Wikipedia receives. We conduct such an study using a sample of users' requests provided by the Wikimedia Foundation in the form of Squid log lines. Our sample contains more that 14,000 million requests from users all around the world and directed to all the projects maintained by the Wikimedia Foundation, including different editions of Wikipedia. This papers describes the work made to characterize the traffic directed to Wikipedia and consisting of the requests sent by its users. Our main aim is to obtain a detailed description of its composition in terms of the percentages corresponding to the different types of requests making part of it. The benefits from our work may range from the prediction of traffic peaks to the determination of the kind of resources most often requested, which can be useful for scalability considerations

Photocatalytic activity in the in-flow degradation of NO on porous TiO2 –coated glasses from hybrid inorganic–organic thin films prepared by a combined ALD/MLD deposition strategy

A combined ALD/MLD (where ALD and MLD stand for atomic and molecular layer deposition, respectively) deposition strategy using TiCl4, H2 O and HQ (hydroquinone) as precursors has been applied for the preparation of inorganic–organic thin films on soda-lime glasses. The alternate deposition of TiO2 layers, by pulsing TiCl4 /H2 O (ALD), and hybrid layers, using TiCl4 /HQ (MLD), results in the formation of thin films that are precursors for porous TiO2-coatings after removal of the HQ template by annealing. The coated-glassed show good photocatalytic activity in the degradation of NO with up to 15% reduction of NO concentration in three successive photocatalytic cycles of 5 h each. Surface Scanning Electron Microscopy (SEM) images show that the TiO2-coating is composed of large grains that are made up of finer subgrains resulting in a porous structure with an average pore size of 3–4 nm. Transmission Electron Microscopy (TEM) images show two regions, a porous columnar structure on top and a denser region over the glass substrate. Energy Dispersive X-Ray (EDX) analysis, nanocrystal electron diffraction and Raman spectroscopy confirm the presence of the anatase phase, which, together with the porosity of the material, accounts for the observed photocatalytic activity. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Millikelvin magnetic relaxation measurements of alpha-Fe2O3 antiferromagnetic particles

In this paper we report magnetic relaxation data for antiferromagnetic alpha-Fe2O3 particles of 5 nm mean diameter in the temperature range 0.1 K to 25 K. The average spin value of these particles S=124 and the uniaxial anisotropy constant D=1.6x10^-2 K have been estimated from the experimental values of the blocking temperature and anisotropy field. The observed plateau in the magnetic viscosity from 3 K down to 100 mK agrees with the occurrence of spin tunneling from the ground state Sz = S. However, the scaling M vs Tln(nu t) is broken below 5 K, suggesting the occurrence of tunneling from excited states below this temperature.Comment: 4 pages (two columns), 4 figure

Spectral Analysis of Guanine and Cytosine Fluctuations of Mouse Genomic DNA

We study global fluctuations of the guanine and cytosine base content (GC%) in mouse genomic DNA using spectral analyses. Power spectra S(f) of GC% fluctuations in all nineteen autosomal and two sex chromosomes are observed to have the universal functional form S(f) \sim 1/f^alpha (alpha \approx 1) over several orders of magnitude in the frequency range 10^-7< f < 10^-5 cycle/base, corresponding to long-ranging GC% correlations at distances between 100 kb and 10 Mb. S(f) for higher frequencies (f > 10^-5 cycle/base) shows a flattened power-law function with alpha < 1 across all twenty-one chromosomes. The substitution of about 38% interspersed repeats does not affect the functional form of S(f), indicating that these are not predominantly responsible for the long-ranged multi-scale GC% fluctuations in mammalian genomes. Several biological implications of the large-scale GC% fluctuation are discussed, including neutral evolutionary history by DNA duplication, chromosomal bands, spatial distribution of transcription units (genes), replication timing, and recombination hot spots.Comment: 15 pages (figures included), 2 figure

5-Nitro-2-(piperidin-1-yl)benzaldehyde

In the structure of the title compound, C12H14N2O3, the piperidine ring adopts a chair conformation and the aryl substitutent occupies an equatorial position

Size and shape of supported zirconia nanoparticles determined by x-ray photoelectron spectroscopy

6 pages, 7 figures, 1 table.-- PACS: 68.55.Ac; 68.55.Jk; 79.60.DpThe initial stages of growth of zirconia nanoparticles deposited on SiO2, Y2O3, and CeO2 substrates have been studied by the x-ray photoelectron spectroscopy peak shape analysis. ZrO2 was deposited by plasma decomposition of a volatile Zr(OtBu)4 precursor. The electronic interactions at each particular interface formed have been followed by means of the modified Auger parameter of the deposited Zr cations. They were quantified by means of Wagner plots and the chemical state vectors of the systems. The observed changes in these local electronic probes as the amount of deposit was increased have been correlated to the particular ZrO2 nanostructures identified on each substrate considered. A Volmer-Weber (islands) growth mechanism has been found for all the substrates considered. Moreover, clear indications have been found of a columnar growth for the case of ZrO2 deposited on SiO2.We thank the Spanish Ministry of Science and Education (MAT2004-01558) for financial support.Peer reviewe