Les jeunes face au marché du travail en France: entre difficultés d´insertion et stratégies de pénétration

En une génération, entre 1975 et 1995, le paysage du marché du travail auquel les jeunes font face a radicalement changé.

Traité général des pesches : et histoire des poissons qu'elles fournissent tant pour la subsistance des hommes que pour plusieurs autres usages qui ont rapport aux arts et au commerce. [3 volumes bound in 2 parts in folio]

Early illustrated book about fish, fishing and fisheries by one of the preeminent scientific investigators of the French enlightenment. This work deals extensively with the species of fish found in Europe and beyond, their habits and habitats, techniques and equipment used in fishing and fish processing, and many other aspects of these endeavours. Roughly 185 engraved plates illustrate the text. The scans for this version come from 3 volumes bound in two parts in folio.

Voyage au Brésil / M. et Mme. Agassiz ; abrégé sur la traduction de F. Vogeli par J. Belin-de Launay et contenant une Carte e 16 gravures sur bois

Jean Louis Rodolphe Agassiz foi professor e naturalista suíço naturalizado americano. Nasceu em Motiers, em 28 de maio de 1807, e morreu em Cambridge, em 1873. Estudou em Universidades suíças e alemãs, doutorando-se em Medicina, em Munique, em 1830. Em 1846, fixou-se nos Estados Unidos, onde lecionou em Harvard, e, em 1861, tornou-se cidadão americano. O estudo e a classificação de espécies de peixes brasileiros despertou-lhe o interesse pelo Brasil e , em 1865, chegou ao País à frente de uma expedição científica, que ficou conhecida como Thayer Expedition, custeada pelo milionário americano Nathanael Thayer e patrocinada pelo Imperador D. Pedro II. Permaneceu no País por quinze meses, explorando o Rio Amazonas e o interior cearense, período em que classificou 1.800 espécies da fauna ictiológica. Dessa viagem, resultou o livro A journey in Brasil. Seus estudos de Zoologia e Paleontologia, assim como os dos glaciares da Europa e da América, tornaram-se célebre. A obra científica de Agassiz é constituída por mais de quatrocentos volumes.

Second mémoire présenté par les Etats Unis du Brésil au gouvernement de la Confédération Suisse, arbitre choisi selon les stipulations du Traité conclu a Rio de Janeiro, le 10 Avril 1897, entre le Brésil et la France : frontières entre le Brésil et la Guyane Française

Nota de conteúdo : V.1. Memoire en reponse aux allegations de la France, accompagne de quelques cartes -- V. 2-3. Documents accompagnes de notes explicatives ou rectificatives, 1. ptie, 1536-1713 ; 2. ptie, 1713-1896 -- V. 4. Texte original de documents traduits dans les tomes 2 et 3 -- V. 5. Album : fac-simile de quelques documents reproduits aux tomes 2, 3 et 4 -- V. 6. Atlas : contenant 86 cartes.

Voyage au Brésil, dans les années 1815, 1816 et 1817

Ouvrage enrichi d'un superbe atlas, compose de 41 planches gravées en taille-douce, et de trois carte.

Schottky barriers on compound semiconductors: I. HgSe highly electronegative contacts. II. Au Schottky barriers on n-Ga_(1-x)Al_xAs

I. HgSe is deposited on various semiconductors, forming a semimetal/semiconductor "Schottky barrier" structure. Polycrystalline, evaporated HgSe produces larger Schottky barrier heights on n-type semiconductors than does Au, the most electronegative of the elemental metals. The barrier heights are about 0.5 eV greater than those of Au on ionic semiconductors such as ZnS, and 0.1 to 0.2 eV greater for more covalently bonded semiconductors. A novel structure,which is both a lattice matched heterostructure and a Schottky barrier, is fabricated by epitaxial growth of HgSe on CdSe using hydrogen transport CVD. The Schottky barrier height for this structure is 0.73 ± 0.02 eV, as measured by the photoresponse method. This uncertainty is unusually small; and the magnitude is greater by about a quarter volt than is achievable with Au, in qualitative agreement with ionization potential arguments.

II . The Schottky barrier height of Au on chemically etched n-Ga_1-x Al_xAs was measured as a function of x. As x increases, the barrier height rises to a value of about 1.2 eV at x ≈ 0.45 , then decreases to about 1.0 eV as x approaches 0.83. The barrier height deviates in a linear way from the value predicted by the "common anion" rule as the AlAs mole fraction increases. This behavior is related to chemical reactivity of the Ga_1-x Al_xAs surface.

Part I. Energy straggling of ^4He below 2.0 MeV in Al, Ni, Au and Pt. Part II. Studies of the Ti-W metallization system on Si

Part I.

In recent years, backscattering spectrometry has become an important tool for the analysis of thin films. An inherent limitation, though, is the loss of depth resolution due to energy straggling of the beam. To investigate this, energy straggling of ⁴He has been measured in thin films of Ni, Al, Au and Pt. Straggling is roughly proportional to square root of thickness, appears to have a slight energy dependence and generally decreases with decreasing atomic number of the adsorber. The results are compared with predictions of theory and with previous measurements. While Ni measurements are in fair agreement with Bohr's theory, Al measurements are 30% above and Au measurements are 40% below predicted values. The Au and Pt measurements give straggling values which are close to one another.

Part II.

MeV backscattering spectrometry and X-ray diffraction are used to investigate the behavior of sputter-deposited Ti-W mixed films on Si substrates. During vacuum anneals at temperatures near 700°C for several hours, the metallization layer reacts with the substrate. Backscattering analysis shows that the resulting compound layer is uniform in composition and contains Ti, Wand Si. The Ti:W ratio in the compound corresponds to that of the deposited metal film. X-ray analyses with Reed and Guinier cameras reveal the presence of the ternary Ti_xW_(1-x)Si₂ compound. Its composition is unaffected by oxygen contamination during annealing, but the reaction rate is affected. The rate measured on samples with about 15% oxygen contamination after annealing is linear, of the order of 0.5 Å per second at 725°C, and depends on the crystallographic orientation of the substrate and the dc bias during sputter-deposition of the Ti-W film.

Au layers of about 1000 Å thickness were deposited onto unreacted Ti-W films on Si. When annealed at 400°C these samples underwent a color change,and SEM micrographs of the samples showed that an intricate pattern of fissures which were typically 3µm wide had evolved. Analysis by electron microprobe revealed that Au had segregated preferentially into the fissures. This result suggests that Ti-W is not a barrier to Au-Si intermixing at 400°C.

Superconductivity, spin-glass properties, and ferromagnetism in amorphous La-Gd-Au alloys

The superconducting and magnetic properties of splat cooled amorphous alloys of composition (La_100-xGd_x)₈₀Au₂₀ (0 ≤ x ≤ 100) have been studied. The La₈₀Au₂₀ alloys are ideal type II super-conductors (critical temperature T_c = 3.5° K ). The concentration range (x less than 1) where superconductivity and spin-glass freezing n1ight coexist has been studied in detail. The spin-glass alloys (0 less than x less than 70) exhibit susceptibility maxima and thermomagnetic history effects. In the absence of complications due to crystal field and enhanced matrix effects, a phenomenological model is proposed in which the magnetic clusters are treated as single spin entities interacting via random forces using the molecular field approach. The fundamental parameters (such as the strength of the forces and the size of clusters) can be deduced from magnetization measurements. The remanent magnetization is shown to arise from an interplay of the RKKY and dipolar forces. Magnetoresistivity results are found to be consistent with the aforementioned picture. The nature of magnetic interactions in an amorphous matrix is also discussed. The moment per Gd atom (7µ_B) is found to be constant and close to that of the crystalline value throughout the concentration range investigated. Finally, a detail study is made of the critical phenomena and magnetic properties of the amorphous ferromagnet: Gd₈₀Au₂₀. The results are compared with recent theories on amorphous magnetism.

Observations of 1-6 MeV Jovian electrons at 1 AU and a study of their propagation

The 1-6 MeV electron flux at 1 AU has been measured for the time period October 1972 to December 1977 by the Caltech Electron/Isotope Spectrometers on the IMP-7 and IMP-8 satellites. The non-solar interplanetary electron flux reported here covered parts of five synodic periods. The 88 Jovian increases identified in these five synodic periods were classified by their time profiles. The fall time profiles were consistent with an exponential fall with τ ≈ 4-9 days. The rise time profiles displayed a systematic variation over the synodic period. Exponential rise time profiles with τ ≈ 1-3 days tended to occur in the time period before nominal connection, diffusive profiles predicted by the convection-diffusion model around nominal connection, and abrupt profiles after nominal connection.

The times of enhancements in the magnetic field, │B│, at 1 AU showed a better correlation than corotating interaction regions (CIR's) with Jovian increases and other changes in the electron flux at 1 AU, suggesting that │B│ enhancements indicate the times that barriers to electron propagation pass Earth. Time sequences of the increases and decreases in the electron flux at 1 AU were qualitatively modeled by using the times that CIR's passed Jupiter and the times that │B│ enhancements passed Earth.

The electron data observed at 1 AU were modeled by using a convection-diffusion model of Jovian electron propagation. The synodic envelope formed by the maxima of the Jovian increases was modeled by the envelope formed by the predicted intensities at a time less than that needed to reach equilibrium. Even though the envelope shape calculated in this way was similar to the observed envelope, the required diffusion coefficients were not consistent with a diffusive process.

Three Jovian electron increases at 1 AU for the 1974 synodic period were fit with rise time profiles calculated from the convection-diffusion model. For the fits without an ambient electron background flux, the values for the diffusion coefficients that were consistent with the data were k_x = 1.0 - 2.5 x 10²¹ cm²/sec and k_y = 1.6 - 2.0 x 10²² cm²/sec. For the fits that included the ambient electron background flux, the values for the diffusion coefficients that were consistent with the data were k_x = 0.4 - 1.0 x 10²¹ cm²/sec and k_y = 0.8 - 1.3 x 10²² cm²/sec.

Vision 2050: changement climatique, pêche et aquaculture en Afrique de l’Ouest Du 14 au 16 avril 2010, Dakar, Sénégal

Ce rapport présente les activités et les résultats de l’atelier Vision 2050: Changement climatique, pêche et aquaculture en Afrique de l’Ouest. Les objectifs de l’atelier étaient de discuter les questions critiques et les incertitudes auxquelles est confronté le secteur de la pêche et de l’aquaculture au Ghana, au Sénégal et en Mauritanie, d’élaborer des scénarios sectoriels pour 2050 et de discuter de l’implication de ces scénarios dans le contexte du changement climatique pour ces pays et la région ouest africaine.

Campagnes Nizery: Togo 3 (16 au 18/08/83) et Togo 4 (28 au 30/11/83). Resultats des chalutages

This publication gives the results of the bottom trawlings made during the cruises Togo 3 and logo 4 by the oceanographic research vessel "Andre NIZERY" on the continental shelf of Togo during the estimation program of halieutic resources. The report includes: 1 - The report of the cruises Togo 3 and Togo 4 2 - Some information on the presentation of the results 3 - The trawl recording cards for the 2 cruises 4 - The length frequency distributions of the measured samples.

Campagne Nizery Togo 7 (19 au 21-O7-84): resultats des chalutages

This publication gives the results of the bottom trawlings made during the cruise TOGO 7 by the oceanographic research vessel Andre Nizery on the continental shelf of Togo during the estimation program of halieutic resources.

Campagnes Chalci, Chalci 84-01 (du 17 au 25-01-84) et Chalci 84-02 (du 03 au 11-07-84): resultats des chalutages

This publication gives the results of bottom trawlings made during the cruises CHALCI 84-01 and CHALCI 84-02 by the oceanographic research vessel "Andre NIZERY" sur le plateau continental ivoirien.

Space-selective precipitation of Au nanoparticles inside silica gel

Au colloids were prepared by irradiation with a Nd:YAG laser. Au nanoparticles were characterized by absorption spectra, transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. It is found that the wavelength of the laser has no effect on the size but the number of the Au nanoparticles. By irradiating a transparent silica gel doped with gold ions with the focused laser in the gel and subsequent exposing in air, a space-selective pattern of letter "P" consisting of Au nanoparticles was observed inside the silica gel.