Quicksort with unreliable comparisons: a probabilistic analysis

We provide a probabilistic analysis of the output of Quicksort when comparisons can err.Comment: 29 pages, 3 figure

Characterization of the angular memory effect of scattered light in biological tissues.

This is the final version of the article. Available via open access from Optical Society of America via the DOI in this record.High resolution optical microscopy is essential in neuroscience but suffers from scattering in biological tissues and therefore grants access to superficial brain layers only. Recently developed techniques use scattered photons for imaging by exploiting angular correlations in transmitted light and could potentially increase imaging depths. But those correlations ('angular memory effect') are of a very short range and should theoretically be only present behind and not inside scattering media. From measurements on neural tissues and complementary simulations, we find that strong forward scattering in biological tissues can enhance the memory effect range and thus the possible field-of-view by more than an order of magnitude compared to isotropic scattering for ∼1 mm thick tissue layers.This work was funded by European Research Council Grant 278025 and the Agence Nationale de la Recherche (Investissements d’Avenir ANR-10-LABX-54 MEMO LIFE, ANR-11-IDEX- 0001-02 PSL* Research University). We thank Prof. Georg Maret for enabling Sam Schott’s stay at institut Langevin and his support of the project and David Martina for technical help in the development of the experimental setup

Transaction Support for DataWeb Applications - A Requirement\u27s Perspective

W eb-based purely providing read-only access to information in terms of static HTML pages. Rather, more and more web-based information systems store (part of) the information within a database system (DBS) and generate HTML pages on demand. Such information systems are often called DataWeb Applications. Different users interact with the system, and often they perform changes concurrently. As an example in the area of electronic commerce, consider a web-based tourism information system, where an unpredictable number of a priori unknown tourists are allowed to book various tourism facilities at the same time. Whereas financial and security issues of such electronic commerce transactions are extensively discussed in literature, very few work exists on the database transaction aspect in terms of consistency and reliability of electronic commerce transactions and of DataWeb applications in general. The objective of this paper is to discuss the specific requirements that different architectures of DataWeb applications and the web itself pose on transaction management, and to identify promising technologies for enabling web transaction services

High energy neutrino yields from astrophysical sources II: Magnetized sources

We calculate the yield of high energy neutrinos produced in astrophysical sources for arbitrary interaction depths $\tau_0$ and magnetic field strengths $B$. We take into account energy loss processes like synchrotron radiation and diffusion of charged particles in turbulent magnetic fields as well as the scattering of secondaries on background photons and the direct production of charm neutrinos. Meson-photon interactions are simulated with an extended version of the SOPHIA model. Diffusion leads to an increased path-length before protons leave the source of size R_s and therefore magnetized sources lose their transparency below the energy $E\sim 10^{18}{\rm eV} (R_s/{\rm pc}) (B/{\rm mG}) \tau_0^{1/\alpha}$, with $\alpha=1/3$ and 1 for Kolmogorov and Bohm diffusion, respectively. Moreover, the neutrino flux is suppressed above the energy where synchrotron energy losses become important for charged particles. As a consequence, the energy spectrum and the flavor composition of neutrinos are strongly modified both at low and high energies even for sources with \tau_0\lsim 1.Comment: 15 pages, 16 figure

The Effects of Communication on the Partnership Solution to the Commons

© 2017, Springer Science+Business Media Dordrecht. Organizing individual appropriators into output sharing groups has been found to effectively solve the tragedy of the commons problem. We experimentally investigate the robustness of this solution by introducing different channels of communication that naturally arise from group competitions. In the absence of communication, we confirm that output sharing can introduce sufficient free riding to offset over-harvesting and results in full efficiency. Allowing local communication within output-sharing groups substantially decreases this efficiency enhancement because it reduces free riding and boosts between-group competition. Yet the efficiency level is still significantly higher than that achieved when global communication is allowed among all appropriators in a conventional common pool resource without output sharing. The efficiency-reducing effect of local communication is mitigated when random partners instead of fixed partners are sharing output over time, and is nearly eliminated when random partners are formed with users who belong to different communication groups

Molecular tuning of the magnetic response in organic semiconductors

The tunability of high-mobility organic semi-conductors (OSCs) holds great promise for molecular spintronics. In this study, we show this extreme variability - and therefore potential tunability - of the molecular gyromagnetic coupling ("g-") tensor with respect to the geometric and electronic structure in a much studied class of OSCs. Composed of a structural theme of phenyl- and chalcogenophene (group XVI element containing, five-membered) rings and alkyl functional groups, this class forms the basis of several intensely studied high-mobility polymers and molecular OSCs. We show how in this class the g-tensor shifts, $\Delta g$, are determined by the effective molecular spin-orbit coupling (SOC), defined by the overlap of the atomic spin-density and the heavy atoms in the polymers. We explain the dramatic variations in SOC with molecular geometry, chemical composition, functionalization, and charge life-time using a first-principles theoretical model based on atomic spin populations. Our approach gives a guide to tuning the magnetic response of these OSCs by chemical synthesis

Characterization of the South Atlantic marine boundary layer aerosol using an Aerodyne Aerosol Mass Spectrometer

International audienceMeasurements of the submicron fraction of the atmospheric aerosol in the marine boundary layer were performed from January to March 2007 (Southern Hemisphere summer) onboard the French research vessel Marion Dufresne in the Southern Atlantic and Indian Ocean (20° S?60° S, 70° W?60° E). For chemical composition measurements an Aerodyne High-Resolution-Time-of-Flight AMS was used to measure mass concentrations and species-resolved size distributions of non-refractory aerosol components in the submicron range. Within the "standard" AMS compounds (ammonium, chloride, nitrate, sulfate, organics) "sulfate" is the dominating species in the marine boundary layer reaching concentrations between 50 ng m?3 and 3 ?g m?3. Furthermore, what is seen as "sulfate" by the AMS seems to be mostly sulfuric acid. Another sulfur containing species that can ubiquitously be found in marine environments is methanesulfonic acid (MSA). Since MSA has not been directly measured before with an AMS, and is not part of the standard AMS analysis, laboratory experiments needed to be performed in order to be able to identify it within the AMS raw data and to extract mass concentrations for MSA from the field measurements. To identify characteristic air masses and their source regions backwards trajectories were used and averaged concentrations for AMS standard compounds were calculated for each air mass type. Sulfate mass size distributions were measured for these periods showing a distinct difference between oceanic air masses and those from African outflow. While the peak size in the mass distribution was roughly 250 nm in marine air masses it was shifted to 470 nm in African outflow air. Correlations between the mass concentrations of sulfate, organics and MSA were calculated which show a narrow correlation for MSA with sulfate/sulfuric acid coming from the ocean but not with continental sulfate