Literature Overview - Privacy in Online Social Networks

In recent years, Online Social Networks (OSNs) have become an important\ud part of daily life for many. Users build explicit networks to represent their\ud social relationships, either existing or new. Users also often upload and share a plethora of information related to their personal lives. The potential privacy risks of such behavior are often underestimated or ignored. For example, users often disclose personal information to a larger audience than intended. Users may even post information about others without their consent. A lack of experience and awareness in users, as well as proper tools and design of the OSNs, perpetuate the situation. This paper aims to provide insight into such privacy issues and looks at OSNs, their associated privacy risks, and existing research into solutions. The final goal is to help identify the research directions for the Kindred Spirits project

Structural and magnetic properties of E-Fe_{1-x}Co_xSi thin films deposited via pulsed laser deposition

We report pulsed laser deposition synthesis and characterization of polycrystalline Fe1-xCox Si thin films on Si (111). X-ray diffraction, transmission electron, and atomic force microscopies reveal films to be dense, very smooth, and single phase with a cubic B20 crystal structure. Ferromagnetism with significant magnetic hysteresis is found for all films including nominally pure FeSi films in contrast to the very weak paramagnetism of bulk FeSi. For Fe1-xCoxSi this signifies a change from helimagnetism in bulk, to ferromagnetism in thin films. These ferromagnetic thin films are promising as a magnetic-silicide/silicon system for polarized current production, manipulation, and detection.Comment: 12 pages, 4 figures accepted in the Applied Physics Letter

Catalysis in Real Time Using X-Ray Lasers

We describe how the unique temporal and spectral characteristics of X-ray free-electron lasers (XFEL) can be utilized to follow chemical transformations in heterogeneous catalysis in real time. We highlight the systematic study of CO oxidation on Ru(0001), which we initiate either using a femtosecond pulse from an optical laser or by activating only the oxygen atoms using a THz pulse. We find that CO is promoted into an entropy-controlled precursor state prior to desorbing when the surface is heated in the absence of oxygen, whereas in the presence of oxygen, CO desorbs directly into the gas phase. We monitor the activation of atomic oxygen explicitly by the reduced split between bonding and antibonding orbitals as the oxygen comes out of the strongly bound hollow position. Applying these novel XFEL techniques to the full oxidation reaction resulted in the surprising observation of a significant fraction of the reactants at the transition state through the electronic signature of the new bond formation

Uptake of agroforestry-based crop management in the semi-arid Sahel – Analysis of joint decisions and adoption determinants.

Open Access JournalIntroduction: Agroforestry plays a vital role in maintaining and developing the resilience and productivity of farms and landscapes. Scientific evidence from the Sahel region suggests that integration of trees and shrubs has the potential to improve temperature and moisture levels whilst providing bio-based fertilizer that contributes to increased yields of annual crops. However, little is known about the factors that influence the diusion of agroforestry. This study examines joint decisions on the use of agroforestry alongside other complementary agricultural practices and disentangles agroforestry awareness fromadoption and disadoption decisions. Methods: Our analysis is based on a comprehensive farm-level dataset covering almost 3,000 farm households in Mali and Senegal. A large number of adoption determinants are utilized, with a special focus on information access, information flows and social groups. Results: The findings suggest that extension access and training participation boost awareness of agroforestry-based soil fertility management, while information provided by public extension, NGOs and community members is strongly associated with higher adoption intensity. In the analysis of disadoption, farmer-to-farmers exchange in the community was found to be a key factor in the decision to maintain agroforestry use. Membership in cooperatives and youth groups appear to have a favorable eect on awareness and adoption in Mali, but less so in the Senegalese case. Similarly, only results from Mali show that adoption of agroforestry is accompanied by the adoption of other sustainable intensification practices and lower use of synthetic pesticides. Discussion: We conclude that in order to support the transition to more widespread agroforestry-based soil fertility management, it is essential to strengthen public and NGO-based advisory systems that fully engage with local knowledge networks

Sex Determination in Honeybees: Two Separate Mechanisms Induce and Maintain the Female Pathway

Sex determination in honeybees is realized by the csd and the fem gene that establish and maintain, throughout development, sexual fates via the control of alternative splicing

Antibioprophylaxie pour chirurgie de médecine humanitaire en zone de conflit au Mali

Objectif : Identifier les antibiotiques utilisés et évaluer notre pratique en médecine humanitaire. Patients et Méthode : Etude prospective de 30 jours. La saisie et l’analyse des données ont été faites par Windows 8, Epi info 3.5.3 fr et le khi² pour le test statistique. Résultats : Soixante-trois (63) patients répondaient aux critères. L’âge moyen était de 33,3 ± 18, 5 ans. Les femmes rurales prédominaient. Les urgences représentaient 65,1% des cas. L’indication de l'antibioprophylaxie était Gynéco-obstétricale dans 63, 5% suivie de la chirurgie viscérale dans 20,6%, de l’urologie dans 11,1% et de la traumatologie dans 4,8%. Les patients étaient ASA I dans 69,8%. La classe d’Altémeier était II dans 81%. Une antibioprophylaxie a été faite dans 88,9%. Les β lactamines en monothérapie ont été les plus utilisées dans 84,1% suivies de l’association β lactamine-imidazole dans 9,5%, de l’association β lactamine-aminoside dans 1,6% et les quinolones dans 1,6%. Le délai entre l’administration de l’antibiotique et l’induction anesthésique était de : 6 ± 2,4 minutes. L’antibiotique a été administré entre 25 et 40 minutes avant l’incision chirurgicale. Une complication infectieuse a été observée dans 11, 1%. L’évolution était favorable dans 98,4%.Conclusion : Même en situation de crise sanitaire, l’utilisation de l’antibiotique au bloc opératoire doit répondre à des critères dont l’écologie microbienne et le site opératoire sont déterminants

Selective ultrafast probing of transient hot chemisorbed and precursor states of CO on Ru(0001)

We have studied the femtosecond dynamics following optical laser excitation of CO adsorbed on a Ru surface by monitoring changes in the occupied and unoccupied electronic structure using ultrafast soft x-ray absorption and emission. We recently reported [M. Dell’Angela et al. Science 339 1302 (2013)] a phonon-mediated transition into a weakly adsorbed precursor state occurring on a time scale of >2  ps prior to desorption. Here we focus on processes within the first picosecond after laser excitation and show that the metal-adsorbate coordination is initially increased due to hot-electron-driven vibrational excitations. This process is faster than, but occurs in parallel with, the transition into the precursor state. With resonant x-ray emission spectroscopy, we probe each of these states selectively and determine the respective transient populations depending on optical laser fluence. Ab initio molecular dynamics simulations of CO adsorbed on Ru(0001) were performed at 1500 and 3000 K providing insight into the desorption process

X ray emission spectroscopy of bulk liquid water in no man s land

The structure of bulk liquid water was recently probed by x ray scattering below the temperature limit of homogeneous nucleation TH of amp; 8764;232 K [J. A. Sellberg et al., Nature 510, 381 384 2014 ]. Here, we utilize a similar approach to study the structure of bulk liquid water below TH using oxygen K edge x ray emission spectroscopy XES . Based on previous XES experiments [T. Tokushima et al., Chem. Phys. Lett. 460, 387 400 2008 ] at higher temperatures, we expected the ratio of the 1b1 amp; 8242; and 1b1 amp; 8242; amp; 8242; peaks associated with the lone pair orbital in water to change strongly upon deep supercooling as the coordination of the hydrogen H bonds becomes tetrahedral. In contrast, we observed only minor changes in the lone pair spectral region, challenging an interpretation in terms of two interconverting species. A number of alternative hypotheses to explain the results are put forward and discussed. Although the spectra can be explained by various contributions from these hypotheses, we here emphasize the interpretation that the line shape of each component changes dramatically when approaching lower temperatures, where, in particular, the peak assigned to the proposed disordered component would become more symmetrical as vibrational interference becomes more importan

Strong Influence of Coadsorbate Interaction on CO Desorption Dynamics on Ru(0001) Probed by Ultrafast X-Ray Spectroscopy and \u3cem\u3eAb Initio\u3c/em\u3e Simulations

We show that coadsorbed oxygen atoms have a dramatic influence on the CO desorption dynamics from Ru(0001). In contrast to the precursor-mediated desorption mechanism on Ru(0001), the presence of surface oxygen modifies the electronic structure of Ru atoms such that CO desorption occurs predominantly via the direct pathway. This phenomenon is directly observed in an ultrafast pump-probe experiment using a soft x-ray free-electron laser to monitor the dynamic evolution of the valence electronic structure of the surface species. This is supported with the potential of mean force along the CO desorption path obtained from density-functional theory calculations. Charge density distribution and frozen-orbital analysis suggest that the oxygen-induced reduction of the Pauli repulsion, and consequent increase of the dative interaction between the CO 5σ and the charged Ru atom, is the electronic origin of the distinct desorption dynamics. Ab initio molecular dynamics simulations of CO desorption from Ru(0001) and oxygen-coadsorbed Ru(0001) provide further insights into the surface bond-breaking process