Small pigmented eukaryotes play a major role in carbon cycling in the P‐depleted western subtropical North Atlantic, which may be supported by mixotrophy

We found that in the phosphate (PO4)‐depleted western subtropical North Atlantic Ocean, small‐sized pigmented eukaryotes (P‐Euk; < 5 μm) play a central role in the carbon (C) cycling. Although P‐Euk were only ~ 5% of the microbial phytoplankton cell abundance, they represented at least two thirds of the microbial phytoplankton C biomass and fixed more CO2 than picocyanobacteria, accounting for roughly half of the volumetric CO2 fixation by the microbial phytoplankton, or a third of the total primary production. Cell‐specific PO4 assimilation rates of P‐Euk and nonpigmented eukaryotes (NP‐Euk; < 5 μm) were generally higher than of picocyanobacteria. However, when normalized to biovolumes, picocyanobacteria assimilated roughly four times more PO4 than small eukaryotes, indicating different strategies to cope with PO4 limitation. Our results underline an imbalance in the CO2 : PO4 uptake rate ratios, which may be explained by phagotrophic predation providing mixotrophic protists with their largest source of PO4. 18S rDNA amplicon sequence analyses suggested that P‐Euk was dominated by members of green algae and dinoflagellates, the latter group commonly mixotrophic, whereas marine alveolates were the dominant NP‐Euk. Bacterivory by P‐Euk (0.9 ± 0.3 bacteria P‐Euk−1 h−1) was comparable to values previously measured in the central North Atlantic, indicating that small mixotrophic eukaryotes likely exhibit similar predatory pressure on bacteria. Interestingly, bacterivory rates were reduced when PO4 was added during experimental incubations, indicating that feeding rate by P‐Euk is regulated by PO4 availability. This may be in response to the higher cost associated with assimilating PO4 by phagocytosis compared to osmotrophy

Heterotrophic bacterial production in the eastern South Pacific: longitudinal trends and coupling with primary production

Spatial variation of heterotrophic bacterial production and phytoplankton primary production were investigated across the eastern South Pacific Ocean (−141° W, −8° S to −72° W, −35° S) in November–December 2004. Bacterial production (³H leucine incorporation) integrated over the euphotic zone encompassed a wide range of values, from 43 mg C m⁻² d⁻¹ in the hyper-oligotrophic South Pacific Gyre to 392 mg C m⁻² d⁻¹ in the upwelling off Chile. In the gyre (120° W, 22° S) records of low phytoplankton biomass (7 mg Total Chla m⁻²) were obtained and fluxes of in situ 14C-based particulate primary production were as low as 153 mg C m⁻² d⁻¹, thus equal to the value considered as a limit for primary production under strong oligotrophic conditions. Average rates of ³H leucine incorporation rates, and leucine incorporation rates per cell (5–21 pmol l⁻¹ h⁻¹ and 15–56×10⁻²¹ mol cell⁻¹ h⁻¹, respectively) determined in the South Pacific gyre, were in the same range as those reported for other oligotrophic subtropical and temperate waters. Fluxes of dark community respiration, determined at selected stations across the transect varied in a narrow range (42–97 mmol O2 m⁻² d⁻¹), except for one station in the upwelling off Chile (245 mmol O2 m⁻² d⁻¹). Bacterial growth efficiencies varied between 5 and 38%. Bacterial carbon demand largely exceeded 14C particulate primary production across the South Pacific Ocean, but was lower or equal to gross community production

Fast Fourier Optimization: Sparsity Matters

Many interesting and fundamentally practical optimization problems, ranging from optics, to signal processing, to radar and acoustics, involve constraints on the Fourier transform of a function. It is well-known that the {\em fast Fourier transform} (fft) is a recursive algorithm that can dramatically improve the efficiency for computing the discrete Fourier transform. However, because it is recursive, it is difficult to embed into a linear optimization problem. In this paper, we explain the main idea behind the fast Fourier transform and show how to adapt it in such a manner as to make it encodable as constraints in an optimization problem. We demonstrate a real-world problem from the field of high-contrast imaging. On this problem, dramatic improvements are translated to an ability to solve problems with a much finer grid of discretized points. As we shall show, in general, the "fast Fourier" version of the optimization constraints produces a larger but sparser constraint matrix and therefore one can think of the fast Fourier transform as a method of sparsifying the constraints in an optimization problem, which is usually a good thing.Comment: 16 pages, 8 figure

Certain Canine Weakly β-Hemolytic Intestinal Spirochetes Are Phenotypically and Genotypically Related to Spirochetes Associated with Human and Porcine Intestinal Spirochetosis

Four canine weakly β-hemolytic intestinal spirochetes associated with intestinal spirochetosis (IS-associated WBHIS) were compared with IS-associated human and porcine WBHIS and the type species for Serpulina hyodysenteriae and S. innocens by using phenotypic and genotypic parameters. The IS-associated canine, human, and porcine WBHIS belonged to a phyletic group distinct from but related to previously described Serpulina type species

Response of CsI(Tl) scintillators over a large range in energy and atomic number of ions (Part I): recombination and delta -- electrons

A simple formalism describing the light response of CsI(Tl) to heavy ions, which quantifies the luminescence and the quenching in terms of the competition between radiative transitions following the carrier trapping at the Tl activator sites and the electron-hole recombination, is proposed. The effect of the delta rays on the scintillation efficiency is for the first time quantitatively included in a fully consistent way. The light output expression depends on four parameters determined by a procedure of global fit to experimental data.Comment: 28 pages, 6 figures, submitted to Nucl. Inst. Meth.

Tourismes 1 - Lieux communes

Cet ouvrage propose une analyse critique des idées reçues que le tourisme alimente à profusion, en particulier au sein de l\u27intelligentsia, soucieuse de préserver l\u27un de ses privilèges mis à mal par le développement du tourisme de masse : l\u27accès à des lieux jadis réservés à une certaine société. Pour cette défense, tous les arguments sont bons, y compris celui de l\u27écologie. Au-delà, le déferlement récurrent des critiques à l\u27endroit du tourisme, depuis les débuts de celui-ci, conduit à s\u27interroger sur les raisons pour lesquelles nos sociétés secrètent et tolèrent un discours anti-touristique, qui est fondamentalement un discours de rejet de l\u27autre : car, sous les dehors patelins du consensus mou, une xénophobie ordinaire est tranquillement véhiculée. Il faut dire que le tourisme est un exutoire idéal : le touriste, c\u27est toujours l\u27autre. Mais les lieux communs, ce sont aussi les lieux produits par le tourisme ou subvertis par lui. En partant des pratiques des touristes pour aboutir à la caractérisation des lieux qu\u27ils fréquentent, cet ouvrage jette les bases d\u27une approche géographique du tourisme. Et, s\u27il est de bon ton de se gausser des touristes, la richesse que le tourisme produit de plus en plus dans le Monde fascine les entreprises, les États et les collectivités territoriales au point que lorsqu\u27un lieu, une région sont en déclin, le tourisme apparaît fréquemment comme l\u27activité de la dernière chance. Cet ouvrage est le premier d\u27une trilogie qui a entrepris d\u27explorer les fondements liés des pratiques et des lieux touristiques, en prenant en compte le tourisme à  l\u27échelle mondiale depuis ses origines et dans le cadre d\u27une entreprise générale de déconstruction des idées reçues et des concepts inégalement opérants, suivie par une reconstruction en deux temps : dans Tourismes 2 (publié en 2005), le lien pratiques-lieux est saisi à travers des "moments de lieux" successifs ; dans Tourismes 3 (2008), l\u27accent est mis sur la durabilité de la révolution touristique, au-delà de la succession de différents systèmes touristiques et de la dynamique propre aux lieux

Management des services dans l’entreprise touristique mondiale en réseau

Ce rapport rédigé en 2012 s\u27intitule Management des services dans l\u27entreprise touristique mondiale en réseau. Il a été rédigé par plusieurs enseignants chercheurs de l\u27UFR ESTHUA.

Towards an IT-based Planning Process Alignment: Integrated Route and Location Planning for Small Package Shippers

To increase the efficiency of delivery operations in small package shipping (SPS), numerous optimization models for routeand location planning decisions have been proposed. This operations research view of defining independent problems hastwo major shortcomings: First, most models from literature neglect crucial real-world characteristics, thus making themuseless for small package shippers. Second, business processes for strategic decision making are not well-structured in mostSPS companies and significant cost savings could be generated by an IT-based support infrastructure integrating decisionmaking and planning across the mutually dependent layers of strategic, tactical and operational planning. We present anintegrated planning framework that combines an intelligent data analysis tool, which identifies delivery patterns and changesin customer demand, with location and route planning tools. Our planning approaches extend standard Location Routing andVehicle Routing models by crucial, practically relevant characteristics like the existence of subcontractors on both decisionlevels and the implicit consideration of driver familiarity in route planning

Revisiting Synthesis Model of Sparse Audio Declipper

The state of the art in audio declipping has currently been achieved by SPADE (SParse Audio DEclipper) algorithm by Kiti\'c et al. Until now, the synthesis/sparse variant, S-SPADE, has been considered significantly slower than its analysis/cosparse counterpart, A-SPADE. It turns out that the opposite is true: by exploiting a recent projection lemma, individual iterations of both algorithms can be made equally computationally expensive, while S-SPADE tends to require considerably fewer iterations to converge. In this paper, the two algorithms are compared across a range of parameters such as the window length, window overlap and redundancy of the transform. The experiments show that although S-SPADE typically converges faster, the average performance in terms of restoration quality is not superior to A-SPADE