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A telepresence-enabled cruise using remotely operated vehicle (ROV) exploration discovered an unusual tubular deposit of Fe-rich hydrothermal nontronite on a young seamount, Mashi, of the Wolf-Darwin lineament in the Galapagos Islands. X-ray diffraction, ICP-MS, ICP-AES, and SEM-EDS analyses show that this deposit is chemically and mineralogically similar to other deep-sea hydrothermal nontronites, indicating a likely formation temperature of about 30° to 50 °C by diffuse hydrothermal activity. These deposits contain mixtures of Fe-rich, Al-poor nontronite and poorly crystalline Fe-Si-oxyhydroxides with bulk compositions of 38–51 wt% SiO 2 and 40–50 wt% Fe 2 O 3 *. The presence of filamentous and spherical structures in the samples suggests that mineral deposition was in part facilitated by chemosynthetic microbes. Although hydrothermal nontronite has been sampled at a number of seafloor sites by coring and dredging, this is the first in situ documentation of its unusual sinuous, tubular structure, on the seafloor. Quantitative image-analysis of ROV imagery indicates that hydrothermal fluid pathways, developed through an underlying pillow lava sequence, likely control the distinctive sinuous morphology.

We provide measurements of thermal diffusivity (D), heat capacity (CP), and viscosity (η) for 12 remelted natural lavas and 4 synthetic glasses and melts, ranging in composition from leucogranite to low-silica basalt, and calculate their thermal conductivity. Both viscosity and the glass transition temperature decrease with decreasing melt polymerization. For basaltic glasses, D is low, ~ 0.5 mm2 s− 1 at room temperature, decreases slightly with increasing temperature, and then drops upon melting to ~ 0.25 to 0.35 mm2 s− 1. Other samples behave similarly. Despite scatter, clear correlations exist between D of glass or melt with Si content, density, NBO/T, and, most strongly, with fragility (m). Glass thermal diffusivity is represented by D = FT− G + HT, where F, G and H are fitting parameters. For melts, ∂ D/∂ T was resolved only for dacite-andesite and MORB: a positive slope is consistent with other iron-bearing samples. Glass and liquid CP depend on density and other physical properties, but not exactly in the same manner as D. We calculate thermal conductivity (k) from these data and demonstrate that k for glasses is described by a Maier-Kelly formula. Large scatter exists for k at 298 K, but silicic to intermediate melts have k between 1.8 and 1.3 Wm− 1 K− 1, whereas basaltic melts are constrained to ~ 1.4 ± 0.1 Wm− 1 k− 1. Low values for thermal diffusivity and viscosity for basaltic melts suggests that basalts transfer heat much more efficiently by advection than by conduction alone, and that partially molten zones in the mantle quickly become more thermally insulating than non-molten zones, potentially contributing to melt localization during decompression melting.

We determined the viscosity and heat capacity of a series of two basaltic liquids containing H 2 O, F, H 2 O + CO 2 , H 2 O + F, and H 2 O + CO 2 + F. One was a natural calc-alkaline basalt from Fuego volcano, Guatemala, and the other was an Fe-free synthetic analog. The viscosity measurements were performed in the low-temperature, high-viscosity range (~ 10 9 –10 12 Pa s) just above the glass transition, where the kinetics of volatile exsolution are slow. Differential scanning calorimetry measurements were performed at atmospheric pressure from room temperature up to ~ 100 K above the glass transition. The water contents ranged from nominally anhydrous to 3 wt.% H 2 O, with F contents up to 2 wt.%, and CO 2 contents up to 0.2 wt.%. Volatiles do not noticeably affect the heat capacity of glasses. The glass transition temperatures obtained from calorimetry and viscometry are in good agreement. Water has a strong viscosity-reducing effect on basaltic melts. F has a measurable viscosity-reducing effect in basaltic melts, but it is significantly smaller than that of water. The combined effects of H 2 O and F on viscosity appear to be additive on a wt.% basis. Both the effects of H 2 O and F on basaltic melts are smaller than those for more polymerized melts. Small quantities of CO 2 do not measurably affect basaltic melt viscosity, at least in the presence of > 1 wt.% water. Future viscosity models incorporating fluorine need to account for the compositional dependence of its effects on dry and hydrous melts.

We determined the heat capacities of four series of glasses and liquids of basaltic and basaltic andesite compositions from remelted volcanic rock samples and Fe-free synthetic analogues. The samples are low-alkali, Ca- and Mg-rich aluminosilicates with non-bridging oxygen to tetrahedrally-coordinated cation ratios (NBO/T) ranging between 0.33 and 0.67. Differential scanning calorimetry measurements were performed at atmospheric pressure between room temperature and ~ 100 K above the glass transition for hydrous samples and up to ~ 1800 K for dry samples. The water contents investigated range up to 5.34 wt.% (16.4 mol%). Water does not measurably affect the heat capacity of glasses. We derived a new value of the partial molar heat capacity of water in silicate glasses of C ¯ P , H 2 O glass = 82.804 + 10 − 3 T − 48.274 × 10 − 5 T − 2 (J/mol K) using our new data in combination with literature data on more and less polymerized compositions. The increase in heat capacity at the glass transition is of the order of ~ 30–40% and generally increases with increasing water content. The onset of the glass transition in hydrous samples occurs below the Dulong–Petit limit of 3R/g atom. The configurational heat capacity, i.e., the magnitude of the change in heat capacity observed at the glass transition, generally increases as polymerization decreases and as water content increases. We obtained a partial molar heat capacity of water in silicate liquids of basaltic composition of ~ 86 J/mol K. This value is comparable to the partial molar values for the major oxides which range from ~ 79 to 230 J/mol K. The partial molar heat capacity of water in silicate liquids appears to be compositionally-dependent, increasing as melt polymerization decreases. Such a dependence is certainly linked to the speciation and structural roles of water in complex silicate melts, however, a single value of ~ 93 J/mol K could reproduce the heat capacity of hydrous liquids of a wide range of NBO/T (0–1.51) at temperatures up to ~ 100 K above the glass transition and water contents of 0–3.76 wt.% with a root-mean square deviation of only 3.23 J/mol K.

We provide new viscosity data in the system SiO2-(Na,K)AlSiO4, for the nepheline-kalsilite and jadeite-leucite joins. We present a configurational entropy model for the viscosity of melts in the system as a function of Na/(Na + K) and Al/(Al + Si) ratios. Our modelling indicates that: i) Viscosity data are reproduced well by a non-ideal, symmetrical form of the parameters Sconf(Tg) and Be, ii) Na-K mixing is the main source of additional entropy in the system based on the limited dependence of Sconf(Tg) and Be parameters on Al/(Al + Si) ratio, iii) Ae likely varies as a function of Al/(Al + Si) ratio. Melt fragility in the system increases with increasing Al/(Al + Si) ratio and is greater for Na or K end-member melts than mixed melts. The viscosity of nominally fully-polymerized melts in the SiO2-(Na,K)AlSiO4 system can be modelled through chemical mixing, without explicit consideration of the important changes in structure related to changes in K/(Na + K) and Al/(Al + Si) ratios.

Extremely high-grade, lava-like welded ignimbrites are produced by many large explosive eruptions with volumes typically 101–103 km3. However, understanding of the physical properties of these unusual deposits, and their transport and depositional mechanisms, is incomplete. The lava-like and rheomorphic Grey’s Landing ignimbrite, Idaho (western United States), provides abundant field evidence supporting the upward migration of a transient

The viscosity of a series of 6 Fe-free, synthetic basaltic andesite liquids, containing up to 3.76 wt.% dissolved water, was measured in the range of the glass transition (10 8 –10 13 Pa s) by parallel-plate viscometry. Concentric-cylinder and falling-sphere viscometry provided high-temperature measurements (10–10 3 Pa s) on basaltic andesite liquids containing up to 2 wt.% dissolved water. The viscosity ( η in Pa s) of Fe-free basaltic andesite can be described as a function of temperature ( T in Kelvin) and water content ( w in wt.%) by the expression log( η ) = − 4.81 + 6940.7/( T − {491.9 − 272.5 log[ w + 0.49]}).This parameterization reproduces 55 viscosity data with a root-mean-square-deviation (RMSD) of 0.24 log units in viscosity. The results of this viscometry study suggest that basaltic andesite liquids should remain very fluid, even while undergoing equilibrium degassing, to pressures as low as 50 MPa (i.e., less than 2 km depth). Only a modest increase in viscosity of at most a factor of 100 would occur in the last 2 km of ascent. Furthermore, our results show that water affects the viscosity of a wide range of depolymerized melts to a similar degree. For example, the addition of 2 wt.% dissolved H 2 O reduces the viscosity of andesite, basaltic andesite, basalt and their alkalic counterpart liquids by a factor of ~ 15–50.

Bubble growth experiments were performed in a piston-cylinder by hydrating albite melt with ∼11 wt.% H2O at 550 MPa followed by rapid decompression at 1 MPa s−1 to pressures of 450 or 400 MPa. At these conditions the melt was supersaturated with ∼0.5 or ∼1.5 wt.% H2O, respectively, which caused rapid exsolution and bubble growth. Results at 1200 °C demonstrate that portions of the initial cumulative bubble-area distributions may be characterized by a power law with an exponent near 1, but they rapidly evolve to exponential distributions and approach a unimodal distribution after 32 h of growth. This evolution occurs by the growth of larger bubbles at the expense of smaller ones. The growth rate of the average bubble radius in these experiments is described by a power law whose exponent is 0.35, close to the theoretical exponent of 1/3 for phase growth in which coalescence is dominated by Ostwald ripening of the bubbles. Over the range of pressures and water contents investigated at 1200 °C, the bubble-size distributions and growth rate are not significantly affected by changes in the amount of exsolved water or by splitting the decompression path into two steps. Similar decompression experiments at 800 °C are dominated by smaller bubbles than in the 1200 °C experiments and also demonstrate exponential cumulative size distributions, but consistently contain a small fraction of larger bubbles. The growth rate of these bubble radii cannot be fit with a power law, but a logarithmic dependence of the bubble radii on time is possible, suggesting a difference in the growth mechanisms at low and high temperatures. This difference is attributed to the orders of magnitude changes in melt viscosity and water diffusion in the melt as the temperature varies from 800 to 1200 °C. At 1200 °C the transport properties of albite melt resemble those of natural basaltic melts whereas at 800 °C the properties are similar to those of andesitic to dacitic melts. The decompression rate used in this study exceeds natural rates by one to two orders of magnitude. Thus, these results indicate that natural mafic-to-intermediate magmas supersaturated with only a small excess of water should easily nucleate bubbles during ascent and that bubble growth in mafic magmas will proceed much more rapidly than in andesitic to dacitic magmas. Intermediate composition magmas also may be capable of forming bimodal bubble-size distributions even in the case when only one nucleation event occurred. The rapid evolution of the bubble-size distribution from a power law to an exponential may be useful in constraining the time duration between bubble nucleation and the quenching of natural samples.

Study objectives To conduct a comprehensive and comparative study of prospectively collected bad dream and nightmare reports using a broad range of dream content variables. Design Correlational and descriptive. Setting Participants' homes. Participants Three hundred thirty-one adult volunteers (55 men, 275 women, 1 not specified; mean age = 32.4 ± 14.8 y). Interventions N/A. Measurement and results Five hundred seventy-two participants kept a written record of all of their remembered dreams in a log for 2 to 5 consecutive weeks. A total of 9,796 dream reports were collected and the content of 253 nightmares and 431 bad dreams reported by 331 participants was investigated. Physical aggression was the most frequently reported theme in nightmares, whereas interpersonal conflicts predominated in bad dreams. Nightmares were rated by participants as being substantially more emotionally intense than were bad dreams. Thirty-five percent of nightmares and 55% of bad dreams contained primary emotions other than fear. When compared to bad dreams, nightmares were more bizarre and contained substantially more aggressions, failures, and unfortunate endings. Conclusions The results have important implications on how nightmares are conceptualized and defined and support the view that when compared to bad dreams, nightmares represent a somewhat rarer-and more severe-expression of the same basic phenomenon.

Significant individual differences exist in dream recall frequency (DRF) but some variance is likely attributable to instrument choice in measuring DRF. Three hundred and fifty eight participants estimated their weekly DRF and recorded their dreams in either a narrative log (n = 165) or checklist log (n = 193) for 2–5 weeks. There was an early peak in DRF within the first week of both types of prospective logs after which DRF remained relatively stable. Although the two groups did not differ in their estimated DRF, significantly fewer dreams were reported per week on the narrative logs and only checklist logs yielded significantly higher DRF than participants’ questionnaire estimates. The interactions between DRF measures did not vary across groups with low, medium or high baseline levels of DRF. Keeping a dream log does not necessarily increase DRF and narrative logs’ time consuming nature can impact subjects’ motivation to report all of their dreams over time.

Studies on nightmare frequency have yielded inconsistent results. We compared the frequency of nightmares and bad dreams obtained with retrospective methods (annual and monthly estimates) and with two types of prospective measures (narrative and checklist logs). Four hundred and eleven participants completed retrospective estimates of nightmare and bad dream frequency and recorded their dreams in either narrative or checklist logs for 2-5 weeks. When measured prospectively with narrative logs, nightmare frequency was marginally higher than the 1-year estimate (P = 0.057) but not significantly different from the 1-month estimate (P0.05). Prospective bad dream frequency was significantly greater than the two retrospective estimates (ps0.0005). There were no significant differences in the frequency of nightmares and bad dreams reported prospectively with narrative versus checklist logs (ps0.05). However, checklist logs yielded a significantly greater number of everyday dreams per week (P0.0001). Taken together, the results provide partial support for the idea that when compared to daily logs, retrospective self-reports significantly underestimate current nightmare and bad dream frequency. Prospective studies of dream recall and nightmare frequency should take into account the type of log used, its duration, and the participants' level of motivation over time.

We present a suite of 21 high-temperature, uniaxial deformation experiments performed on 25 by 50 mm unjacketed cores of porous (Φ ∼ 0.8) sintered rhyolitic ash. The experiments were performed at, both, atmospheric (dry) and elevated water pressure conditions (wet). Experiments used a constant displacement rate of 2.5 × 10− 6 m s− 1 corresponding to a strain rate (ɛo) of ∼ 5 × 10− 5 s− 1; a single experiment was run at 2.5 × 10− 5 m s− 1 (ɛo ∼ 5 × 10− 4 s− 1). Dry experiments were conducted mainly at 900 °C, but also included a suite of lower temperature experiments at 850, 800 and 750 °C. Wet experiments were performed at ∼ 650 °C under water pressures of 1, 2.5, and 5 MPa, and at a fixed PH2O of ∼ 2.5 MPa for temperatures of ∼ 385, 450, and 550 °C. During deformation, strain is manifest by shortening of the cores, reduction of porosity, flattening of ash particles, and radial increase of the cores. The continuous reduction of porosity leads to a dynamic transient strain-dependent rheology and requires strain to be partitioned between a volume (porosity loss) and a shear (radial increase) component. These data demonstrate the effect of porosity on the rheology of dry and hydrous melts. The effect of increasing porosity is to expand the window for ductile deformation for dry melts by delaying the onset of brittle deformation by ∼ 50 °C (875 °C to 825 °C). The effect is more pronounced in hydrous melts (∼ 0.67–0.78 wt.% H2O) where the ductile to brittle transition is depressed by ∼ 140 to 150 °C. Increasing water pressure also delays the onset of strain hardening due to compaction-driven porosity reduction. These rheological data are pertinent to any volcanic processes involving high-temperature porous magmas (e.g., magma flow in conduits, welding of pyroclastic materials).

We describe an experimental apparatus used to perform deformation experiments relevant to the volcanological sciences. The apparatus supports low-load, high-temperature deformation experiments under dry and wet conditions on natural and synthetic samples. The experiments recover the transient rheology of complex (melt ± porosity ± solids) volcanic materials during uniaxial deformation. The key component to this apparatus is a steel cell designed for high-temperature deformation experiments under controlled water pressure. Experiments are run under constant displacement rates or constant loads; the range of accessible experimental conditions include: 25–1100 °C, load stresses 0 to 150 MPa, strain rates 10 −6 to 10 −2 1/s, and fluid pressures 0–150 MPa. The apparatus is calibrated against standard values of viscosity using constant-load experiments on cores of NIST (NBS) 717a borosilicate glass. We also report results of constant-displacement rate (~10 −6 m/s) experiments on porous (~70%) sintered cores of ash from the Rattlesnake Tuff. The cores of volcanic ash were deformed in experiments under ambient (“dry”) and elevated water pressures (“wet”). Dry experiments at ~870 °C show an increase in effective viscosity (10 9.5 to 10 10.4 Pa·s) with increasing strain (~30%) due to porosity reduction during compaction. Experiments under ~1–3 MPa P H 2 O recover lower values of apparent viscosity (10 9.2 to 10 9.4 Pa·s) despite being run at lower temperatures (640–665 °C). The wet experiments also do not show a rise in viscosity with increased strain (decreasing porosity) as observed in dry experiments. Rather, the presence of an H 2 O fluid phase expands the window of viscous deformation and delays the onset of strain hardening that normally accompanies porosity reduction.

Three silicate glasses were hydrated at high pressure and then heated at atmospheric pressure to exsolve the water into bubbles and create foams. The bubble size distribution in these foams was measured by x-ray microtomography on the GSECARS BM-13 beamline at the Advanced Photon Source. The bubble area distributions were measured in two dimensions using the image slices produced from the microtomography and the software ImageJ. The bubble volume distributions were measured from the three-dimensional tomographic images with the BLOB3D software. We found that careful analysis of the microtomography data in both two and three dimensions was necessary to avoid the physically unrealistic, experimental artifact of identifying and counting many small bubbles whose surfaces were not defined by a septum of glass. When this artifact was avoided the foams demonstrated power-law distributions of bubble sizes in both two and three dimensions. Conversion of the power-law exponents for bubble areas measured in two dimensions to exponents for bubble volumes usually agreed with the measured three dimensional volume exponents. Furthermore, the power-law distributions for bubble volumes typically agree with multiple theories of bubble growth, all of which yield an exponent of 1 for the cumulative bubble volume distribution. The measured bubble volume distributions with exponents near 0.3 can be explained by diffusive growth as proposed by other authors, but distributions with exponents near 1.4 remain to be explained and are the subject of continuing research on the effects of water concentration and melt viscosity on foaming behavior.

The effect of endurance swim training (3 hours per day, 5 days/week, for 10 weeks) on hepatic glucose production (HGP) in liver perfused in situ for 60 minutes with glucagon and insulin was studied in Sprague-Dawley rats. The experiments were performed in fed rats and in rats fasted for 24 hours, but with lactate (8 mmol/L) added to the perfusion medium. Liver glycogen content was significantly lower in fasted than fed rats (fasted untrained and trained: 14 +/- 4 and 11 +/- 3 micromol glycosyl U/g of liver wet weight (WW); fed untrained and trained: 205 +/- 11 and 231 +/- 11 micromol glycosyl U/g of liver WW; not significantly different in trained and untrained rats). Glucagon increased HGP in the 4 experimental groups, but the increases were more rapid and pronounced in trained than in untrained rats in both fed and fasted states. HGP values (area under the curve [AUC] in micromol/g of liver WW) were significantly higher in trained fed (112.1 +/- 7.1 v 85.9 +/- 12.2 in untrained rats) than in trained fasted rats (50.8 +/- 4.4 v 34.7 +/- 3.6 in untrained rats). When compared with untrained rats, the total amount of glucose released by the liver in response to glucagon in trained rats was approximately 30% higher in the fed state and approximately 45% larger in the fasted state. These results indicate that endurance training increases the response of both glycogenolysis and gluconeogenesis to glucagon.

Hepatic Glucagon Receptor In Rats: Effect Of Type 1 Diabetes. JOHNATAN LAMANQUE*, JESSICA MORISSETTE, ALEXANDRE MELANCON, GENEVIEVE ROBERT, FRANCOIS PERONNET AND CAROLE LAVOIE. Universite du Quebec a Trois-Rivieres et Universite de Montreal, Quebec. The purpose of this study was to describe the density and binding properties of hepatic glucagon receptor in rats with insulin-treated type 1 diabetes (single injection of 80 mg/kg of streptozotocin i.p.). One week after the diabetes was established, and for the duration of the 8week experimentation period, blood glucose concentration was normalized by subcutaneous insulin 7-mm long implants. No difference was observed for weight (435 ± 15 and 423 ± 7 g) and blood glucose concentration (7.0 ± 1.2 and 7.7 ± 0.6 mmol/L) for the diabetes (n = 6) and control groups (n = 5) at the time of sacrifice. Plasma membranes were purified from liver, and saturation kinetics were obtained by incubation with ()I-labelled glucagon. Saturating curves analysis indicated a similar glucagon receptor density in liver from diabetic and control animals (Bmax = 3.38 ± 0.48 and 3.09 ± 0.12 pmol/mg of proteins), but the affinity of the receptor was lower in diabetic rats (Kd = 1.02 ± 0.10 vs 0.33 ± 0.05 nM). These preliminary results suggest that in liver from type 1 diabetic rats treated with insulin, the density of hepatic glucagon receptor is normal but their affinity is lower than in liver from control animals. This finding could partly explain the lost of glucagon sensibility acquired with type 1 diabetes. Supported by Diabete Trois-Rivieres, Diabete-Quebec and NSERC. ABSTRACT #78

Alors que le capital humain demeure l’actif stratégique le plus important pour assurer la compétitivité des entreprises et leur pérennité, que savons-nous de la gestion des ressources humaines dans les PME ? Ce texte présente une revue de la littérature scientifique concernant la gestion des ressources humaines (GRH) dans les PME. Les 167 articles empiriques répertoriés à partir des bases de données bibliographiques ABI/Inform et Repère sont classés en fonction de la nature des connaissances produites. Ces articles sont ainsi divisés en cinq catégories : (1) les pratiques RH utilisées dans les PME, (2) leurs caractéristiques distinctives par rapport aux grandes entreprises ; (3) les déterminants de l’adoption des pratiques RH ; (4) leurs conséquences sur la performance des PME ; (5) les processus à travers lesquels les pratiques RH sont modifiées. Les résultats montrent que les études ont surtout consisté à vérifier si le modèle de GRH des grandes entreprises s’applique aux PME. La formalisation des pratiques RH a également beaucoup retenu l’attention. De façon générale, peu d’études ont été réalisées sur chacun des divers aspects de la GRH et leurs résultats sont discordants. Des pistes de recherche sont proposées en vue de favoriser le développement des connaissances., While human capital remains the most important strategic asset for ensuring business competitiveness and sustainability, what do we know about human resource management in SMEs? This paper presents a literature review on human resource management (HRM) in SMEs. The 167 empirical articles found by searching the ABI/Inform and Repère databases are classified according to the nature of the knowledge they generated. These articles are then sorted into five categories according to whether they relate to (1) HR practices used in SMEs, (2) their distinctive characteristics compared to large enterprises, (3) the determinants of the adoption of HR practices, 4) their impact on the performance of SMEs, and (5) the processes through which HR practices are modified. The results show that the main focus of the studies was to verify whether large enterprises HRM model applies to SMEs. The formalization of HR practices has also attracted attention. In general, few studies have been done on the various aspects of HRM and their results are conflicting. Several research directions are proposed., Aunque el capital humano se mantiene como el activo estratégico más inportante para asegurar la competitividad y sostenibilidad de las empresas, qué sabemos realmente de la gestión de recursos humanos en las PyME ? Este texto representa una revisión de la literatura científica relacionada con la gestión de los recursos humanos (GRH) en la pequeña y mediana empresa (PyME). Los ciento sesenta y siete artículos empíricos registrados a partir de las bases de datos bibliográficas ABI/Inform y Repère se catalogan de acuerdo a cinco categorías, establecidas a partir de la naturaleza de los conocimientos obtenidos. Los artículos se clasifican entonces en : (1) las prácticas RH utilizadas en la PyME, (2) las características que las distinguen de las grandes empresas, (3) los factores determinantes de la aplicación de dichas prácticas RH, (4) el impacto de las prácticas RH en el rendimiento de la PyME y (5) los procedimiento mediante los cuales se pueden modificar las mismas. Los análisis aplicados demuestran que los estudios se concentran principalmente en demostrar si los modelos de GRH de las grandes empresas se pueden aplicar a la PyME y en la formalización de las prácticas RH. De manera general pocos estudios se realizan sobre los diversos aspectos de la GRH y los resultados son discordantes. Los estudios proponen algunas líneas de investigación en vistas de favorecer el desarrollo de conocimientos.

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