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La pandémie de COVID-19 bouleverse l’industrie du tourisme et risque de se faire sentir pendant encore plusieurs mois, voire des années. Il faudra ensuite s’en remettre le plus rapidement possible, mais encore faudra-t-il que les voyageurs soient au rendez-vous en grand nombre. Cet article présente les résultats d’une consultation auprès de voyageurs (n=1084) en début de confinement au Canada. Il semble que les voyages à proximité du domicile seront favorisés et que les voyages récréatifs ne reprendront que lorsque les conditions seront propices et que les tarifs seront concurrentiels. La littérature sur les désastres et les crises sanitaires démontre qu’il est primordial de rassurer les voyageurs quant à l’autorisation du gouvernement de voyager en toute sécurité avant même d’amorcer des campagnes publicitaires pour encourager le voyage à l’étranger. Les analyses permettent de constater que les voyageurs fréquents et les millénariaux sont les plus susceptibles de reprendre leurs habitudes de voyage., The COVID-19 pandemic is disrupting the tourist industry and its impact could be felt for many more months, if not years. Tourism will need to recover as fast as possible, but for that to happen, travellers will have to be there in great numbers. This article presents the results of a survey among travellers (n=1,084) at the start of the confinement in Canada. It seems that close-to-home trips will be favoured and that recreational trips will only resume when conditions will be conducive and rates competitive. Literature on disasters and health crises shows that it is crucial to reassure travellers as to the government’s authorization for safe travel before launching advertising campaigns to encourage travelling abroad. Based on the results of the analyses, frequent travellers and millennials are those more likely to return to their travelling habits.

Cette étude visait à connaître le profil de carrière, le niveau de satisfaction envers la formation universitaire reçue ainsi que les activités de perfectionnement professionnel des détenteurs d’un baccalauréat en éducation physique décerné par l’Université de Moncton depuis une trentaine d’années (1968-2001). L’échantillon comprenait 293 diplômés et l’instrument de mesure consistait en une soixantaine de questions. Pour les sujets interrogés, la recherche du premier emploi s’est particulièrement bien déroulée. Un peu plus de la moitié des diplômés enseignent toujours l’éducation physique. Le niveau de satisfaction face aux études et au travail est élevé. Cependant, la plupart des répondants estiment comme peu probable l’obtention d’une promotion., The objective of this research was to identify the career profile, the level of satisfaction with the university education received, as well as the professional development of holders of a bachelor’s degree in physical education, conferred by the Université de Moncton over thirty years (1968-2001). The sample included 293 graduates, whose responses to approximately 60 questions were used as measurement. For those subjects interrogated, the authors found that the first job search went particularly well. A little over half of the graduates are still teaching physical education. The level of satisfaction relative to studies and work is high, however the possibility of an eventual promotion is highly unlikely., El objetivo de este estudio era conocer el perfil de carrera, el nivel de satisfacción hacia la formación universitaria cursada así como las actividades de capacitación profesional de los titulados de una licenciatura en educación física, concedida por la Universidad de Moncton desde hace unos treinta años (1968-2001). La muestra incluía 293 titulados y el instrumento de medición constaba de alrededor de sesenta preguntas. Resultó que para los encuestados, la búsqueda del primer empleo se pasó particularmente bien. Un poco más de la mitad de los titulados siguen enseñando la educación física. Asimismo, el nivel de satisfacción hacia los estudios y el trabajo es elevado. Sin embargo, la mayoría de los encuestados consideran poco probable lograr a conseguir una promoción.

The most condensed crystalline fluoride that appears in the Al(OH)3-tren-HFaq.-ethanol system at 190 °C is found to be [H4tren]3/2·(Al6F24)·3H2O. The structure is monoclinic, P21/c, with a = 21.939(1) A, b = 6.7180(2) A, c = 23.329(1) A, β = 111.324(2)°. ∞(Al6F24) chains result from the connection of (Al7F30)9− polyanions by opposite AlF6 octahedra. Hydrogen bonds are established between the ∞(Al6F24) chains and ordered or disordered [H4tren]4+ cations and water molecules.

The preparation of the rare earth containing oxide fluoride glasses LnF 3 (Ln; Y through Lu)–BaF 2 –AlF 3 –GeO 2 in which the nominal content of LnF 3 reached 60 mol% in maximum and their basic properties such as density, refractive index and glass transition temperature were investigated and summarized in detail. Especially, in order to discuss the local structure around the rare earth ion in the glass, the Judd–Ofelt analysis (discussion with Ω parameters) of the HoF 3 –BaF 2 –AlF 3 –GeO 2 glasses was carried out. The unique fluorescent behavior and the magnetic properties of LnF 3 –BaF 2 –AlF 3 –GeO 2 glasses (Ln = Tb and/or Sm) were also studied.

Cette contribution présente une réflexion méthodologique consistant en la comparaison des approches et des méthodes en matière de traitement automatisé des données textuelles, le croisement des outils logiciels, voire l’utilisation des résultats des uns pour les soumettre aux autres, et défend une démarche expérimentale en lexicométrie ou textométrie., This paper presents a methodological reflection comparing various automated data processing techniques, approaches, and methods. It promotes the use of various types of software while working on textual data, explains how results of software can be used as data in different settings and promotes an experimental approach in atextometrical or lexicometrical field.

A new organic–inorganic zirconium (IV) fluoride, [C6N2H14]⋅(Zr2F10)⋅1.5H2O, is prepared by slow evaporation at 45 °C from a solution of Zr4+ and of 1,4-diazabicyclo[2.2.2]-octane (DABCO) in 40% aqueous HF. The structure, determined from single-crystal X-ray diffraction, is monoclinic, space group C 2 / m , a = 19.598 ( 8 ) A , b = 6.658 ( 3 ) A , c = 10.891 ( 3 ) A , β = 101.25 ( 4 ) ° and Z = 4 . Previously unknown ∞(Zr2F10)2− double chains, built up from edge-sharing ZrF7 pentagonal bipyramids and ZrF8 trigonal dodecahedra, are observed. The diprotonated organic cations, water molecules and the ∞(Zr2F10)2− chains are linked by hydrogen bonds.

Malgré l’omniprésence de l’accueil dans le discours touristique, ce concept demeure à la fois imprécis et régulièrement assimilé au service à la clientèle. L’objectif du présent texte est, justement, de mieux comprendre la différence, le cas échéant, entre l’accueil et le service à la clientèle dans l’industrie touristique. La présente démarche exploratoire permet d’émettre certaines hypothèses ou questions qui pourraient être explorées davantage dans des études ultérieures. Une première hypothèse tirée de ces résultats est que les touristes interviewés semblent comprendre la différence entre l’accueil et le service quand on leur explique en quelques mots les deux concepts. Cette compréhension de l’accueil nous conduit à une deuxième hypothèse, à savoir que l’on peut effectivement considérer l’accueil comme étant la « valeur ajoutée du tourisme » (Seydoux, 1984 ; Tremblay, 1991). Outre la comparaison entre le sexe et l’âge, il est intéressant de noter qu’il n’y a pas de différence apparente entre les touristes expérimentés (plus de quatre voyages) et ceux qui le sont moins (un voyage). Néanmoins, dans les commentaires des répondants sur le sujet, il ressort que les touristes moins expérimentés font des commentaires qui témoignent de leurs exigences relativement élevées en matière d’accueil et de service. Par conséquent, il serait intéressant de vérifier l’hypothèse que les touristes peu expérimentés sont plus « exigeants » que les touristes expérimentés en matière d’accueil et de services. Les résultats de notre enquête sont un pas de plus dans l’affirmation de la différence entre l’accueil et le service. Il serait souhaitable que d’autres recherches empiriques soient entreprises dans le but de vérifier ces hypothèses, de mieux comprendre les différences et de démontrer ce que sont véritablement l’accueil et le service en tourisme.

Acta Obstet Gynecol Scand 2002; 81: 195-203. © Acta Obstet Gynecol Scand 2002 Background. To evaluate (a) cadherins and CD44 expression in normal endometrium and in peritoneal endometriosis, and (b) to correlate, their expressions with clinicopathological parameters. Methods. E- and N-cadherin, CD44 isoforms, CD44v3 and CD44v6 expressions were evaluated: (a) by immunoblotting in endometrium ( n = 6) and in peritoneal endometriotic samples ( n = 7) and, (b) by immunohistochemistry in endometrium ( n = 15) and in peritoneal endometriotic samples ( n = 23). Results. By immunoblotting, endometrium expressed E- and N-cadherin, CD44 isoforms, CD44v3 and CD44v6. Similar results were observed in peritoneal endometriosis. By immunohistochemistry, in endometrium, E-cadherin was restricted to epithelial cells. Its expression remained constant throughout the menstrual cycle. N-cadherin was detected in both epithelial and stromal cells in the proliferative phase but was restricted to epithelial cells in the secretory ...

(H2DABCO) [FeIII2F8(H2O)2] (I), (H2DABCO)2 [FeIII2F10]·2H2O (II), (HDABCO)4 [FeIII2F10]·10H2O (III), and (HFDABCO)[(FeII(H2O)6) (FeIIIF6)] (IV) are prepared by conventional solvothermal synthesis using a EtOH or DMF solution of FeF2, FeF3, and HF (4%) with DABCO (autoclave, 120 °C, 72 h) to explore the composition space diagram of the (Fe2+,Fe3+)-DABCO-HFaq chemical system.

(H3O)2NaAl3F12 is obtained as minor phase from the solvothermal reaction of Al(OH)3, NaOH, 1,2,4-triazole, and 40% aq.

The new compounds [Ni(en)3]·(TiF6) (I), [PyH]2[Cu(Py)4(TiF6)2] (II), [PyH]2[Cu(Py)4(MoF6)2] (III), [H3O]2 [SiF6(CuF(Py)4)2]·(F)2 (IV), Cu(en)2TiF6 (V), and Cu(en)2SiF6 (VI) are solvothermally synthesized from mixtures of TiO2, MoO2, SiO2, CuO or NiO, HF solution, Py, en, and EtOH (microwave heating, 160 °C, autoclave, 1 h).

Six new compounds, [H4tren][Zr2F12]·H2O (I) (tren: tris-(2-aminoethyl)amine), α-[H4tren][Zr2F12] (II), β-[H4tren][Zr2F12] (III), [H3tren]4 [ZrF8]3·4H2O (IV), α-[H3tren]2 [Ta3O2F16]F (V), and β-[H3tren]2 [Ta3O2F16]F (VI) are found to exist in the ZrF4 (Ta2O5)—tren—HFaq.—EtOH systems at 190 °C.

[(NH2)2C=NH2] 2Ti5O5F12 is synthesized by microwave-assisted solvothermal reaction of TiF4 and [(NH2)2C=NH]·HCl (EtOH, microwaves, autoclave, 190 °C, 1 h).

Two new zirconium (IV) fluorides, [H 2 dap ]·(Zr 2 F 10 )·H 2 O ( I ) and [H meam ] 2 ·(Zr 2 F 10 )·H 2 O ( II), are synthesized and characterized by X-ray diffraction, thermal techniques and NMR spectroscopy. I is triclinic ( P 1 ¯ ) with a = 6.805 (1) A, b = 8.361(1) A, and c = 11.853 (2) A, α = 94.54(1)°, β = 105.44(1)°, γ = 108.75(1)°. II is monoclinic ( C 2 /m ) with a = 10.340(6) A, b = 6.624(4) A, c = 8.758(6) A and β = 110.57(3)°. The structure determinations, performed from single crystal X-ray diffraction data, lead to the R/R w reliability factors 0.041/0.113 for I and 0.057/0.177 for II . The structures are built up from ZrF 7 and ZrF 8 units in I and only ZrF 8 units in II . The polyhedra share common edges in order to form two different ZrF 5 layers that are also found in [H 2 C 2 H 10 N 2 ]·(Zr 2 F 10 )·H 2 O and (H 3 O) 2 ·(Zr 2 F 10 )·H 2 O. On heating at 145 °C, [H 2 dap ]·(Zr 2 F 10 )·H 2 O decomposes to give the anhydrous form [H 2 dap ]·(Zr 2 F 10 ) that undergoes two successive phase transformations at 220 °C and 290 °C. 19 F NMR spectroscopy confirms the structural features of [H 2 dap ]·(Zr 2 F 10 )·H 2 O ( I ): two sets of three lines with a relative intensity 1:2:2 are attributed to five bridging fluorine atoms and to five nonbridging fluorine atoms. This spectroscopy demonstrates that a noticeable substitution of F − anions by hydroxyl OH − groups is excluded, together with the eventual substitution of H 2 O by HF molecules.

We present a systematic survey of the structural chemistry of crystalline hybrid fluorides. About a hundred different metal fluoride building units are represented in these systems, predominantly as anionic moieties, ranging from simple tetrahedral or octahedral dimers to larger oligomeric species, complex chains, layers and, ultimately, three-dimensional frameworks. Although a few compositional spaces have been moderately well explored and certain key features of their chemistries are understood, the underlying message is that this is an area still in its infancy, ripe for further and wider exploration, rich in new crystal-chemical characteristics and, perhaps, with great potential for the development of new physical and chemical functionalities.

The crystal structure of KGd(CO3)F2 is solved from single crystal X-ray diffraction, and the luminescence properties of KGd(CO3)F2 are analysed. KGd(CO)3F2:Eu3+ is orthorhombic, of space group Fddd (No. 70), with a=7.006(2) A, b=11.181(3) A and c=21.865(6) A. The three-dimensional network is built up from infinite sheets of GdO4F4 polyhedra in the (a, b) plane, which are linked by the carbonate groups and K+ ions along c. A single crystallographic site for Eu3+ with C2 symmetry, as predicted by X-ray study, is confirmed from the luminescence spectrum recorded at 77 K. Simulation of the crystal field effects is also carried out.

The structure of L-EuBO 3 is revised by using the centric P-1 space group with two crystallographic sites for Eu 3+ , in perfect agreement with the luminescence results (site A and site B). The structure, refined from single crystal X-ray diffraction data, is triclinic, space group P-1, Z =4, with a =6.468(7) A, b =6.477(7) A, c =6.220(7) A, α =107.78(6)°, β =108.00(7)°, γ =93.07(4)°, R 1 =0.025, wR 2 =0.062. The three-dimensional network is built up from corrugated sheets of EuO 8 polyhedra, approximately parallel to the (111) planes. Luminescence analysis indicates that site to site energy transfer is efficient at 77 K and is phonon assisted from site B to site A. At 12 K, this site B to site A phonon coupling disappears.

A composition space diagram is used to establish the stability regions of hybrid fluoroaluminates synthesized by solvothermal reactions in the Al(OH)(3)-HguaCl-HF(aq)-EtOH system. The syntheses are conducted using microwave heating at 190 degrees C for 1 h. The structures of two new guanidinium fluoroaluminates, (H(3)O)(2) x [Hgua](16) x (Al(4)F(18))(3) x H(2)O and [Hgua](2) x (Al(5)F(17)), are reported. (H(3)O)(2) x [Hgua](16) x (Al(4)F(18))(3) x H(2)O, determined from single-crystal X-ray data, consists of discrete (Al(4)F(18))(6-) polyanions, while [Hgua](2) x (Al(5)F(17)), solved from powder X-ray diffraction data in direct space, contains unprecedented Al(5)F(17) layers constructed from the intergrowth of HTB and perovskite columns. A disorder of H(2)O and H(3)O(+) is evidenced in (H(3)O)(2) x [Hgua](16) x (Al(4)F(18))(3) x H(2)O together with a disorder of guanidinium cations in the interlayer space of [Hgua](2) x (Al(5)F(17)).

The luminescence of Eu 3+ in sodium europium hydroxyfluoride carbonate, Na 2 Eu(CO 3 )F 2.5 (OH) 0.5 , synthesized by hydrothermal growth at low temperature, is presented. The structure is orthorhombic and is built up from EuO 3 (F, OH) 6 polyhedra linked by triangular faces and edges. The emission spectrum consists of groups of sharp lines attributed to 5 D 0 → 7 F 0–4 transitions of one low symmetry site for Eu 3+ in agreement with the crystallographic analysis. 23 from 25 expected electronic levels for 7 F J ( J =0–4) manifolds are fitted by the phenomenological crystal field parameters in the approaching C 2v point symmetry. The simulation is achieved with very good root mean square ( rms ) deviation of 5.3 cm −1 . The crystal field strength parameter, N v , is weak ( N v =1652). Satellite vibronics of carbonate groups coupled to electronic transitions are also observed.

Nd2Gd2O3F6 was prepared by solid-solid reaction between 1 mol Nd2O3 and 2 mol GdF3 at 1100°C for 3 h in an argon flow. X-ray powder diffraction-Rietveld analysis revealed that the crystal system of Nd2Gd2O3F6 was assigned to the monoclinic structure with the cell parameters; a0=0.3973 nm, b0=1.123 nm, c0=0.5595 nm and β=134.75°. The ionic arrangement was suggested to be slightly disordered in the Nd2Gd2O3F6 crystal lattice in contrast to in the Nd2Eu2O3F6 with the high ordered ionic arrangement. It was assumed that the slightly disordered ionic arrangement in Nd2Gd2O3F6 resulted in the smaller electrical conductivity of Nd2Gd2O3F6 (0.2 S m−1 at 600°C) than that of Nd2Eu2O3F6 (5.4 S m−1 at 600°C). Nd2Gd2O3F6 was confirmed to be stable up to ca. 650°C in air, and converted into NdGdO3 (monoclinic) at ca. 1350°C through the metastable state of NdGdO2F2 (rhombohedral) at ca. 850°C by the pyro-hydrolysis. The rate of pyro-hydrolysis was analyzed as the tarnishing reaction represented by the surface reaction control. The electrical conductivity largely declined with decreasing fluorine content due to the pyro-hydrolysis. This cause was considered due to disappearance of the vacant sites for oxide ion migration according to change in the crystal structure.

Two new hybrid fluorides, {[(C2H4NH3)3NH]4+}2 · (H3O)+ · [Al7F30]9– (I) and {[(C2H4NH3)3NH]4+}2 · [Al7F29]8– · (H2O)2 (II), are synthesized by solvothermal method. The structure determinations are performed by single crystal technique. The symmetry of both crystals is triclinic, sp. gr. P 1, I: a = 9.1111(6) A, b = 10.2652(8) A, c = 11.3302(8) A, α = 110.746(7)°, β = 102.02(1)°, γ = 103.035(4)°, V = 915.9(3) A3, Z = 1, R = 0.0489, Rw = 0.0654 for 2659 reflections, II: a = 8.438(2) A, b = 10.125(2) A, c = 10.853(4) A, α = 106.56(2)°, β = 96.48(4)°, γ = 94.02(2)°, V = 877.9(9) A3, Z = 1, R = 0.0327, Rw = 0.0411 for 3185 reflections. In I, seven corner-sharing AlF6 octahedra form a [Al7F30]9– anion with pseudo 3 symmetry; such units are found in the pyrochlore structure. The aluminum atoms lie at the corners of two tetrahedra, linked by a common vertex. In II, similar heptamers are linked in order to build infinite (Al7F29)n8– chains oriented along a axis. In both compounds, organic moieties are tetra protonated and establish a system of hydrogen bonds N–H…F with four Al7F309– heptamers in I and with three inorganic chains in II. Von Isolierten Polyanionen zur 1-D-Struktur: Synthese und Kristallstruktur der Hybridfluoride {[(C2H4NH3)3NH]4+}2 · (H3O)+ · [Al7F30]9– und {[(C2H4NH3)3NH]4+}2 · [Al7F29]8– · (H2O)2 Zwei neue Hybridfluoride {[(C2H4NH3)3NH]4+}2 · (H3O)+ · [Al7F30]9– (I) und {[(C2H4NH3)3NH]4+}2 · [Al7F29]8– · (H2O)2 (II) wurden durch Hydrothermalsynthese dargestellt. Die Kristallstrukturen wurden mittels Rontgenbeugung an Einkristallen bestimmt. Beide Verbindungen kristallisieren triklin in der zentrosymmetrischen Raumgruppe P 1. I: a = 9,1111(6) A, b = 10,2652(8) A, c = 11,3302(8) A, α = 110,746(7)°, β = 102,02(1)°, γ = 103,035(4)°, V = 915,9(3) A3, Z = 1, R = 0.0489, Rw = 0.0654 fur 2659 beobachtete Reflexe, II: a = 8,438(2) A, b = 10,125(2) A, c = 10,853(4) A, α = 106,56(2)°, β = 96,48(4)°, γ = 94,02(2)°, V = 877,9(9) A3, Z = 1, R = 0.0327, Rw = 0.0411 fur 3185 beobachtete Reflexe. Die Kristallstruktur von I enthalt [Al7F30]9–-Anionen mit Pseudosymmetrie 3 aus sieben eckenverknupften AlF6-Oktaedern; solche Einheiten werden in der Pyrochlor-Struktur gefunden. In der Kristallstruktur von II bilden ahnliche heptamere Anionen unendliche (Al7F29)n8–-Ketten entlang der kristallographischen a-Achse. In beiden Verbindungen bestehen durch vierfach protonierte organische Kationen zusatzliche Verknupfungen uber Wasserstoffbruckenbindungen. In der Struktur I ist der organische Teil mit vier [Al7F30]9–-Anionen, in der Struktur II mit drei anorganischen Ketten verbunden.

The structure of Ba2Co(CO3)2F2, obtained by hydrothermal synthesis, is determined from X-ray single crystal diffraction data (1085 unique reflections, R=0.034, Rw=0.078). Ba2Co(CO3)2F2 is orthorhombic, space group Pbca (Z=4), with a=6.6226(6), b=11.494(2), c=9.021(2) A and V=686.7(4) A3. It can be described from infinite (0 1 0) layers of [CoO4F2] octahedra and CO2−3 entities or from [BaO3F]∞ sheets of [BaO7F3] polyhedra. Antiferromagnetic order occurs below TN≈6 K.

The synthesis and the crystal structure of two isostructural fluoride carbonates are presented. BaZn(CO3)F2 and BaMn(CO3)F2, obtained by hydrothermal growth (T=650 °C, P=210 MPa, t=48 h), are hexagonal, P63/m, Z=2, with a=4.8523(8), c=9.854(1) A for BaZn(CO3)F2 and a=4.9120(8), c=9.919(1) A for BaMn(CO3)F2. Their structures are solved by X-ray diffraction; the reliability factors are R/Rw=0.016/0.039 and R/Rw=0.019/0.046 for BaZn(CO3)F2 and BaMn(CO3)F2, respectively. The 3D network is built up from [MO3F2] (M=Zn, Mn) polyhedra and CO2−3 groups, which lie in (0 0 0 1) planes. The structures, which derive from the structure of KPu(CO3)O2, are very similar to the structures of two fluoride borates, BaAl(BO3)F2 and BaGa(BO3)F2, recently published.

Thirteen phases are now evidenced in the composition space diagram of the Al(OH) 3 – tren –HF–ethanol system at 190 °C. Solvothermal syntheses are performed under microwave heating. Six new organic–inorganic fluorides crystallise and their structures are determined: (H 3 O)·[H 4 tren ] 2 ·(AlF 6 ) 3 ·6H 2 O ( P -1, Z = 2), [H 3 tren ] 2 ·(AlF 5 (H 2 O)) 3 ·8H 2 O ( C 2/ c , Z = 8), [H 3 tren ] 4 ·(AlF 6 ) 2 ·(Al 2 F 11 )·(F)·10H 2 O ( P 2 1 / n , Z = 2), [H 3 tren ] 2 ·(Al 4 F 18 )·3.5H 2 O ( P 6 3 , Z = 2), [H 3 tren ] 2 ·(Al 4 F 18 ) ( P -1, Z = 1), and [H 3 tren ] 4 ·(Al 8 F 35 )·(OH)·H 2 O ( P -1, Z = 1). The existence domains are approximately located for all phases. Tren amine is tetraprotonated at high HF concentration, otherwise it is triprotonated. A protonated water cluster, H 3 O + (H 2 O) 6 , appears in (H 3 O)·[H 4 tren ] 2 ·(AlF 6 ) 3 ·6H 2 O while a new Al 4 F 18 unit, found in [H 3 tren ] 2 ·(Al 4 F 18 ), is evidenced; it results from corner and edge sharing association of four AlF 6 octahedra. Finally, the structure of [H 3 tren ] 4 ·(Al 8 F 35 )·(OH)·H 2 O revealed the largest known fluoroaluminate polyanion, built from eight vertex sharing AlF 6 octahedra, (Al 8 F 35 ) 11− .

Three new monodimensional hybrid metal (Ti, In, Al) fluorides are synthesized with ethylenediamine ( en ) as a templating agent in solvothermal conditions assisted by microwave heating. All structures involve inorganic chains built up from TiO 2 F 4 octahedra connected by two opposite O 2− vertices in [H 2 en ]·(TiOF 4 ) ( I ), from InF 6 (H 2 O) pentagonal bipyramids linked by F–F edges in [H 2 en ]·(InF 4 (H 2 O)) 2 ·H 2 O ( II ) and from (Al 7 F 30 ) 9− polyanions sharing two opposite AlF 6 octahedra in [H 2 en ] 3 ·(Al 6 F 24 ) ( III ). I is tetragonal, P 4/ ncc , a = 12.761(3) A, c = 8.041(3) A; II is orthorhombic, F 2 dd , a = 6.904(5) A, b = 16.559(5) A, c = 19.777(4) A and III is monoclinic, P 2 1 /n , a = 9.387(2) A, b = 6.710(2) A, c = 21.513(6) A, β = 97.18(3)°.

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Using tris(2-aminoethyl)amine [(C 2 H 4 NH 2 ) 3 N] ( tren ) as a template, two new tantalum fluorides are obtained by slow evaporation of solutions: [H 4 tren ](TaF 7 ) 2 · H 2 O ( I ) and [H 4 tren ](TaF 7 ) 2 ( II ). The structure determinations are performed by single crystal X-ray technique. Structures of I and II are built up from isolated TaF 7 distorted monocapped trigonal prisms or pentagonal bipyramids; charge balance is achieved by tetraprotonated [H 4 tren ] 4+ cations which possess a “scorpion” configuration. In I and II , TaF 7 polyhedra, connected by hydrogen bonds with water molecules in I , lie in corrugated layers; hydrogen bond networks ensure the cohesion between these layers and [H 4 tren ] 4+ cations.

Crystalline samples of Na2M2(BO3)2O ( M = Al , Ga ), Na1.5Ca0.25Ga2(BO3)2O and NaCa0.5Ga2(BO3)2O are prepared by conventional high temperature solid state synthesis technique. Temperature dependent impedance spectroscopy measurements are performed. For Na2Al2(BO3)2O and Na2Ga2(BO3)2O, high and low temperature regimes have to be distinguished. Only one regime is observed for the calcium-substituted samples Na1.5Ca0.25Ga2(BO3)2O and NaCa0.5Ga2(BO3)2O.

In Na4/3Ln26/3(SiO4)6(F1/3O2/3)2 (Ln = La, Ce, Gd) apatites, synthesized by hydrothermal and ceramic methods, Na+ and Ce3+ cations are disordered on 4f sites while O2- and F- anions are disordered in the “apatite” channels. The high U33 value of these anions suggests the onset of conductivity at high temperature.

New sodium lithium rare earth carbonates Na2LiLn(CO3)3 ( Ln = Eu–Er , Yb, Lu, Y) are prepared by hydrothermal synthesis and characterized by single crystal X-ray diffraction, thermal analysis, IR, Raman and NMR spectroscopy. Crystal cells are cubic, a ≈ 14.4 A , space group F d 3 ¯ m (No. 227), Z = 16 . For Na2LiYb(CO3)3, refinements yield R ( F 2 ) = 0.068 and R w ( F 2 ) = 0.202 for 235 unique reflections. The structures are built up from [Li(1)O6] octahedra, [Li(2)O4] tetrahedra and [(Na2/3Ln1/3)O8] polyhedra. NMR spectroscopy shows that Li+ cations are disordered and present a high mobility in their tetrahedral and octahedral coordination polyhedra. Na+ and Ln3+ cations are also disordered; however, Na+ cations adopt preferentially a six-fold coordination. Crystals of Na2LiEu(CO3)3 are highly resistive. Raman and IR lines, associated with carbonate group vibrations, are very broad. Structural correlations exist with Na3Mg(CO3)2Cl northupite and AB2X6 pyrochlores.

Estimation of nutrient load production based on multi-temporal remotely sensed land use data for the Glenelg–Hopkins region in south-west Victoria, Australia, is discussed. Changes in land use were mapped using archived Landsat data and computerised classification techniques. Land use change has been rapid in recent history with 16% of the region transformed in the last 22 years. Total nitrogen and phosphorus loads were estimated using an export coefficient model. The analysis demonstrates an increase in modelled nitrogen and phosphorus loadings from 1980 to 2002. Whilst such increases were suspected from past anecdotal and ad-hoc evidence, our modelling estimated the magnitude of such increases and thus demonstrated the enormous potential of using remote sensing and GIS for monitoring regional scale environmental processes.

International audience; Aims: To isolate, identify, and characterize heterotrophic bacteria in acid-mine drainage that mediate oxidation of As(III). Methods and Results: Samples of acid-mine drainage were collected over a period of 14 months. Heterotrophic and non-obligatory acidophilic bacteria in the samples were cultured on a solid medium (pH 7AE0-7AE2), and three strains were isolated. The three different strains belong to the genus Thiomonas, and have more than 99% homology with the group Ynys1. Culturing in mineral media demonstrated that the isolated strains used thiosulphate as an energy source, and oxidized iron in the presence of thiosulphate. However, none of the strains were able to oxidize arsenic in the presence of thiosulphate, nor could they use iron or arsenic alone as an energy source. In vitro experiments demonstrated that two of the Thiomonas strains were able to oxidize more than 90% of the As(III) present in the acid-mine drainage, whereas no abiotic oxidation of arsenic occurred. Conclusions: Two strains of newly identified Thiomonas sp. found in acid-mine drainage are capable of oxidizing arsenic. Significance and Impact of Study: These results represent the first reported oxidation of arsenic by Thiomonas sp. Biologically mediated oxidation and subsequent immobilization of arsenic is of great interest for the remediation of contaminated mine sites.

Two new carbonates, Na 5 Y(CO 3 ) 4 and Na 5 Yb(CO 3 ) 4 ·2H 2 O, are synthesized by microwave-assisted hydrothermal method and their crystal structures are established by single crystal X-ray diffraction. Na 5 Y(CO 3 ) 4 is monoclinic: P2 1 /c ; a =12.209(3) A, b =10.085(4) A, c =8.783(4) A and β =90.39(3)°; V =1081.4(5) A 3 ; Z =4. Na 5 Yb(CO 3 ) 4 ·2H 2 O, isostructural with Na 5 Sc(CO 3 ) 4 ·2H 2 O, is tetragonal: P-42 1 c ; a =7.593(2) A, c =11.528(8) A; V =664.6(3) A 3 ; Z =2. Dehydration of Na 5 Yb(CO 3 ) 4 ·2H 2 O under argon leads to Na 5 Yb(CO 3 ) 4 , which is isostructural with Na 5 Y(CO 3 ) 4 . In the structure of Na 5 Y(CO 3 ) 4 , YO 9 and Na(1)O 8 polyhedra share vertices and form, with carbonate C(2)O 3 2− and C(3)O 3 2− groups, infinite (100) layers [NaY(CO 3 ) 2 O 6 ] ∞ at x≈ 1 4 ; and x≈ 3 4 . In Na 5 Yb(CO 3 ) 4 ·2H 2 O, YbO 8 and Na(1)O 4 polyhedra share carbonate groups and build [NaYb(CO 3 ) 4 ] ∞ layers.

Phase stability regions in the Na2CO3–YbF3–H2O system at T=190 °C, P=11×105 Pa, t=1 h, microwave heating, and the crystal structures of two new carbonate fluorides Na2Yb(CO3)2F and Na3Yb(CO3)2F2 are presented. Five phases, obtained for [YbF3]⩽0.75 M and [Na]/[Yb]

Cristallisation dans P2 1 /m avec a=7,780, b=8,423 et c=4,993 A, β=96,48°, Z=2; affinement jusqu'a R=0,049. Observation d'une isotypie totale avec la structure CsV 3 O 8 . La structure est construite a partir d'unites pyramide varie V(2)O 5 qui partagent une arete et donnent des polyanions condenses V 2 O 8 6− . Par partage de sommets, il y a formation de chaines infinies le long de b→. Coordination octaedrique pour les atomes V(1) entre ces chaines. Le resultat est un empilement de feuillets (V 3 O 8 − )∞ plisses parallelement au plan (100)

Cristallisation dans P2 1 /m avec a=7,780, b=8,423 et c=4,993 A, β=96,48°, Z=2; affinement jusqu'a R=0,049. Observation d'une isotypie totale avec la structure CsV 3 O 8 . La structure est construite a partir d'unites pyramide varie V(2)O 5 qui partagent une arete et donnent des polyanions condenses V 2 O 8 6− . Par partage de sommets, il y a formation de chaines infinies le long de b→. Coordination octaedrique pour les atomes V(1) entre ces chaines. Le resultat est un empilement de feuillets (V 3 O 8 − )∞ plisses parallelement au plan (100)