Thermal energetics of the New-Guinean moss-forest rat (Rattus niobe) in comparison with other tropical murid rodents.

The thermal energetics of rodents from cool, wet tropical highlands are poorly known. Metabolic rate, body temperature and thermal conductance were measured in the moss-forest rat, Rattus niobe (Rodentia), a small murid endemic to the highlands of New Guinea. These data were evaluated in the context of the variation observed in the genus Rattus and among tropical murids. In 7 adult R. niobe, basal metabolic rate (BMR) averaged 53.6±6.6mLO2h(-1), or 103% of the value predicted for a body mass of 42.3±5.8g. Compared to other species of Rattus, R. niobe combines a low body temperature (35.5±0.6°C) and a moderately low minimal wet thermal conductance cmin (5.88±0.7mLO2h(-1)°C(-1), 95% of predicted) with a small size, all of which lead to reduced energy expenditure in a constantly cool environment. The correlations of mean annual rainfall and temperature, altitude and body mass with BMR, body temperature and cmin were analyzed comparatively among tropical Muridae. Neither BMR, nor cmin or body temperature correlated with ambient temperature or altitude. Some of the factors which promote high BMR in higher latitude habitats, such as seasonal exposure to very low temperature and short reproductive season, are lacking in wet montane tropical forests. BMR increased with rainfall, confirming a pattern observed among other assemblages of mammals. This correlation was due to the low BMR of several desert adapted murids, while R. niobe and other species from wet habitats had a moderate BMR.

Water chemistry and isotope composition of the Acquarossa thermal system, Ticino, Switzerland

The thermal springs of Acquarossa and the nearby mineral springs of Soia have outlet temperatures of 12 degrees to 25 degrees C, TDS of 2290 to 3000 mg/kg and Ca-SO4 to Ca-SO4-HCO3 composition. Chemical geothermometers suggest reservoir temperatures close to 60 degrees C. P-CO2 values at depth are estimated to range from 0.3 to 2 bar. delta D and delta(18)O values indicate a meteoric origin and recharge elevations of 1600 +/- 150 m above sea level (a.s.l.) for these thermal and mineral waters. All these waters discharge from the overturned limb of the Simano nappe, probably dose to the contact between basement and underlying cover rocks. They therefore represent rain waters that descend slowly, heat at depth and locally rise relatively quickly to the surface, preserving part of their physical and chemical characteristics. (C) 1999 CNR. Published by Elsevier Science Ltd. All rights reserved.

Reorganization of a deeply incised drainage: role of deformation, sedimentation and groundwater flow

Deeply incised drainage networks are thought to be robust and not easily modified, and are commonly used as passive markers of horizontal strain. Yet, reorganizations (rearrangements) appear in the geologic record. We provide field evidence of the reorganization of a Miocene drainage network in response to strike-slip and vertical displacements in Guatemala. The drainage was deeply incised into a 50-km-wide orogen located along the North America-Caribbean plate boundary. It rearranged twice, first during the Late Miocene in response to transpressional uplift along the Polochic fault, and again in the Quaternary in response to transtensional uplift along secondary faults. The pattern of reorganization resembles that produced by the tectonic defeat of rivers that cross growing tectonic structures. Compilation of remote sensing data, field mapping, sediment provenance study, grain-size analysis and Ar(40)/Ar(39) dating from paleovalleys and their fill reveals that the classic mechanisms of river diversion, such as river avulsion over bedrock, or capture driven by surface runoff, are not sufficient to produce the observed diversions. The sites of diversion coincide spatially with limestone belts and reactivated fault zones, suggesting that solution-triggered or deformation-triggered permeability have helped breaching of interfluves. The diversions are also related temporally and spatially to the accumulation of sediment fills in the valleys, upstream of the rising structures. We infer that the breaching of the interfluves was achieved by headward erosion along tributaries fed by groundwater flow tracking from the valleys soon to be captured. Fault zones and limestone belts provided the pathways, and the aquifers occupying the valley fills provided the head pressure that enhanced groundwater circulation. The defeat of rivers crossing the rising structures results essentially from the tectonically enhanced activation of groundwater flow between catchments.

Tectonics of the Simplon massif and Lepontine gneiss dome: deformation structures due to collision between the underthrusting European plate and the Adriatic indenter

this study presents a review of published geological data, combined with original observations on the tectonics of the simplon massif and the Lepontine gneiss dome in the Western Alps. New observations concern the geometry of the Oligocene Vanzone back fold, formed under amphibolite facies conditions, and of its root between Domodossola and Locarno, which is cut at an acute angle by the Miocene, epi- to anchizonal, dextral centovalli strike-slip fault. the structures of the simplon massif result from collision over 50 Ma between two plate boundaries with a different geometry: the underthrusted European plate and the Adriatic indenter. Detailed mapping and analysis of a complex structural interference pattern, combined with observations on the metamorphic grade of the superimposed structures and radiometric data, allow a kinematic model to be developed for this zone of oblique continental collision. the following main Alpine tectonic phases and structures may be distinguished: 1. NW-directed nappe emplacement, starting in the Early Eocene (similar to 50 Ma); 2. W, SW and S- verging transverse folds; 3. transpressional movements on the dextral simplon ductile shear zone since similar to 32 Ma; 4. formation of the Bergell - Vanzone backfolds and of the southern steep belt during the Oligocene, emplacement of the mantle derived 31 - 29 Ma Bergell and Biella granodiorites and porphyritic andesites as well as intrusions of 29-25 Ma crustal aplites and pegmatites; 5. formation of the dextral discrete Rhone-Simplon line and the centovalli line during the Miocene, accompanied by the pull-apart development of the Lepontine gneiss dome - Dent blanche (Valpelline) depression. It is suggested that movements of shortening in fan shaped NW, W and sW directions accompanied the more regular NW- to WNW-directed displacement of the Adriatic indenter during continental collision.

Dense deformation field estimation for atlas-based segmentation of pathological MR brain images.

Atlas registration is a recognized paradigm for the automatic segmentation of normal MR brain images. Unfortunately, atlas-based segmentation has been of limited use in presence of large space-occupying lesions. In fact, brain deformations induced by such lesions are added to normal anatomical variability and they may dramatically shift and deform anatomically or functionally important brain structures. In this work, we chose to focus on the problem of inter-subject registration of MR images with large tumors, inducing a significant shift of surrounding anatomical structures. First, a brief survey of the existing methods that have been proposed to deal with this problem is presented. This introduces the discussion about the requirements and desirable properties that we consider necessary to be fulfilled by a registration method in this context: To have a dense and smooth deformation field and a model of lesion growth, to model different deformability for some structures, to introduce more prior knowledge, and to use voxel-based features with a similarity measure robust to intensity differences. In a second part of this work, we propose a new approach that overcomes some of the main limitations of the existing techniques while complying with most of the desired requirements above. Our algorithm combines the mathematical framework for computing a variational flow proposed by Hermosillo et al. [G. Hermosillo, C. Chefd'Hotel, O. Faugeras, A variational approach to multi-modal image matching, Tech. Rep., INRIA (February 2001).] with the radial lesion growth pattern presented by Bach et al. [M. Bach Cuadra, C. Pollo, A. Bardera, O. Cuisenaire, J.-G. Villemure, J.-Ph. Thiran, Atlas-based segmentation of pathological MR brain images using a model of lesion growth, IEEE Trans. Med. Imag. 23 (10) (2004) 1301-1314.]. Results on patients with a meningioma are visually assessed and compared to those obtained with the most similar method from the state-of-the-art.

Nuclear well logging in soils. Calibration of slim hole nuclear tools gamma-gamma and neutron-thermal neutron.

The calculation of elasticity parameters by sonic and ultra sonic wave propagation in saturated soils using Biot's theory needs the following variables : forpiation density and porosity (p, ø), compressional and shear wave velocities (Vp, Vs), fluid density, viscosity and compressibility (Pfi Ilfi Ki), matrix density and compressibility (p" K), The first four parameters can be determined in situ using logging probes. Because fluid and matrix characteristics are not modified during core extraction, they can be obtained through laboratory measurements. All parameters necessitate precise calibrations in various environments and for specific range of values encountered in soils. The slim diameter of boreholes in shallow geophysics and the high cost of petroleum equipment demand the use of specific probes, which usually only give qualitative results. The measurement 'of density is done with a gamma-gamma probe and the measurement of hydrogen index, in relation to porosity, by a neutron probe. The first step of this work has been carried out in synthetic formations in the laboratory using homogeneous media of known density and porosity. To establish borehole corrections different casings have been used. Finally a comparison between laboratory and in situ data in cored holes of known geometry and casing has been performed.

Correction of through-plane deformation artifacts in stimulated echo acquisition mode cardiac imaging.

Attempts to use a stimulated echo acquisition mode (STEAM) in cardiac imaging are impeded by imaging artifacts that result in signal attenuation and nulling of the cardiac tissue. In this work, we present a method to reduce this artifact by acquiring two sets of stimulated echo images with two different demodulations. The resulting two images are combined to recover the signal loss and weighted to compensate for possible deformation-dependent intensity variation. Numerical simulations were used to validate the theory. Also, the proposed correction method was applied to in vivo imaging of normal volunteers (n = 6) and animal models with induced infarction (n = 3). The results show the ability of the method to recover the lost myocardial signal and generate artifact-free black-blood cardiac images.

Test-retest reliability of thermal quantitative sensory testing on two sites within the L5 dermatome of the lumbar spine and lower extremity.

INTRODUCTION: Quantitative sensory testing (QST) is widely used in human research to investigate the integrity of the sensory function in patients with pain of neuropathic origin, or other causes such as low back pain. Reliability of QST has been evaluated on both sides of the face, hands and feet as well as on the trunk (Th3-L3). In order to apply these tests on other body-parts such as the lower lumbar spine, it is important first to establish reliability on healthy individuals. The aim of this study was to investigate intra-rater reliability of thermal QST in healthy adults, on two sites within the L5 dermatome of the lumbar spine and lower extremity. METHODS: Test-retest reliability of thermal QST was determined at the L5-level of the lumbar spine and in the same dermatome on the lower extremity in 30 healthy persons under 40 years of age. Results were analyzed using descriptive statistics and intraclass correlation coefficient (ICC). Values were compared to normative data, using Z-transformation. RESULTS: Mean intraindividual differences were small for cold and warm detection thresholds but larger for pain thresholds. ICC values showed excellent reliability for warm detection and heat pain threshold, good-to-excellent reliability for cold pain threshold and fair-to-excellent reliability for cold detection threshold. ICC had large ranges of confidence interval (95%). CONCLUSION: In healthy adults, thermal QST on the lumbar spine and lower extremity demonstrated fair-to-excellent test-retest reliability.

Fluid-rock-strain feedbacks in extensional shear zones

La présence de fluide météorique synchrone à l'activité du détachement (Farmin, 2003 ; Mulch et al., 2007 ; Gébelin et al., 2011), implique que les zones de cisaillement sont des systèmes ouverts avec des cellules de convections à l'échelle crustale et un intense gradient géothermique au sein du détachement (Morrison et Anderson, 1998, Gottardi et al., 2011). De plus, les réactions métamorphiques liées à des infiltrations fluides dans les zones de cisaillement extensionnel peuvent influencer les paramètres rhéologiques du système (White and Knipe, 1978), et impliquer la localisation de la déformation dans la croûte. Dans ce manuscrit, deux zones de cisaillement infiltrées par des fluides météoriques sont étudiées, l'une étant largement quartzitique, et l'autre de nature granitique ; les relations entre déformation, fluides, et roches s'appuient sur des approches structurales, microstructurales, chimiques et isotopiques. L'étude du détachement du Columbia river (WA, USA) met en évidence que la déformation mylonitique se développe en un million d'années. La phase de cisaillement principal s'effectue à 365± 30°C d'après les compositions isotopiques en oxygène du quartz et de la muscovite. Ces minéraux atteignent l'équilibre isotopique lors de leur recristallisation dynamique contemporaine à la déformation. La zone de cisaillement enregistre une baisse de température, remplaçant le mécanisme de glissement par dislocation par celui de dissolution- précipitation dans les derniers stades de l'activité du détachement. La dynamique de circulation fluide bascule d'une circulation pervasive à chenalisée, ce qui engendre localement la rupture des équilibres d'échange isotopiques. La zone de cisaillement de Bitterroot (MT, USA) présente une zone mylonitique de 600m d'épaisseur, progressant des protomylonites aux ultramylonites. L'intensité de la localisation de la déformation se reflète directement sur l'hydratation des feldspaths, réaction métamorphique majeure dite de « rock softening ». Une étude sur roche totale indique des transferts de masse latéraux au sein des mylonites, et d'importantes pertes de volume dans les ultramylonites. La composition isotopique en hydrogène des phyllosilicates met en évidence la présence (1) d'une source magmatique/métamorphique originelle, caractérisée par les granodiorites ayant conservé leur foliation magmatique, jusqu'aux protomylonites, et (2) une source météorique qui tamponne les valeurs des phyllosilicates des fabriques mylonitiques jusqu'aux veines de quartz non-déformées. Les compositions isotopiques en oxygène des minéraux illustrent le tamponnement de la composition du fluide météorique par l'encaissant. Ce phénomène cesse lors du processus de chloritisation de la biotite, puisque les valeurs des chlorites sont extrêmement négatives (-10 per mil). La thermométrie isotopique indique une température d'équilibre isotopique de la granodiorite entre 600-500°C, entre 500-300°C dans les mylonites, et entre 300 et 200°C dans les fabriques cassantes (cataclasites et veines de quartz). Basé sur les résultats issus de ce travail, nous proposons un modèle général d'interactions fluide-roches-déformation dans les zones de détachements infiltrées par des fluides météoriques. Les zones de détachements évoluent rapidement (en quelques millions d'années) au travers de la transition fragile-ductile ; celle-ci étant partiellement contrôlée par l'effet thermique des circulations de fluide météoriques. Les systèmes de détachements sont des lieux où la déformation et les circulations fluides sont couplées ; évoluant rapidement vers une localisation de la déformation, et de ce fait, une exhumation efficace. - The presence of meteoric fluids synchronous with the activity of extensional detachment zones (Famin, 2004; Mulch et al., 2007; Gébelin et al., 2011) implies that extensional systems involve fluid convection at a crustal scale, which results in high geothermal gradients within active detachment zones (Morrison and Anderson, 1998, Gottardi et al., 2011). In addition, the metamorphic reactions related to fluid infiltration in extensional shear zones can influence the rheology of the system (White and Knipe, 1978) and ultimately how strain localizes in the crust. In this thesis, two shear zones that were permeated by meteoric fluids are studied, one quartzite-dominated, and the other of granitic composition; the relations between strain, fluid, and evolving rock composition are addressed using structural, microstructural, and chemical/isotopic measurements. The study of the Columbia River detachment that bounds the Kettle core complex (Washington, USA) demonstrates that the mylonitic fabrics in the 100 m thick quartzite- dominated detachment footwall developed within one million years. The main shearing stage occurred at 365 ± 30°C when oxygen isotopes of quartz and muscovite equilibrated owing to coeval deformation and dynamic recrystallization of these minerals. The detachment shear zone records a decrease in temperature, and dislocation creep during detachment shearing gave way to dissolution-precipitation and fracturing in the later stages of detachment activity. Fluid flow switched from pervasive to channelized, leading to isotopic disequilibrium between different minerals. The Bitterroot shear zone detachment (Montana, USA) developed a 600 m thick mylonite zone, with well-developed transitions from protomylonite to ultramylonite. The localization of deformation relates directly to the intensity of feldspar hydration, a major rock- softening metamorphic reaction. Bulk-rock analyses of the mylonitic series indicate lateral mass transfer in the mylonite (no volume change), and significant volume loss in ultramylonite. The hydrogen isotope composition of phyllosilicates shows (1) the presence of an initial magmatic/metamorphic source characterized by the granodiorite in which a magmatic, and gneissic (protomylonite) foliation developed, and (2) a meteoric source that buffers the values of phyllosilicates in mylonite, ultramylonite, cataclasite, and deformed and undeformed quartz veins. The mineral oxygen isotope compositions were buffered by the host-rock compositions until chloritization of biotite started; the chlorite oxygen isotope values are negative (-10 per mil). Isotope thermometry indicates a temperature of isotopic equilibrium of the granodiorite between 600-500°C, between 500-300°C in the mylonite, and between 300 and 200°C for brittle fabrics (cataclasite and quartz veins). Results from this work suggest a general model for fluid-rock-strain feedbacks in detachment systems that are permeated by meteoric fluids. Phyllosilicates have preserved in their hydrogen isotope values evidence for the interaction between rock and meteoric fluids during mylonite development. Fluid flow generates mass transfer along the tectonic anisotropy, and mylonites do not undergo significant volume change, except locally in ultramylonite zones. Hydration of detachment shear zones attends mechanical grain size reduction and enhances strain softening and localization. Self-exhuming detachment shear zones evolve rapidly (a few million years) through the transition from ductile to brittle, which is partly controlled by the thermal effect of circulating surface fluids. Detachment systems are zones in the crust where strain and fluid flow are coupled; these systems. evolve rapidly toward strain localization and therefore efficient exhumation.

Thermal energetics and torpor in the common pipistrelle bat, Pipistrellus pipistrellus (Vespertilionidae: Mammalia).

Rate of metabolism and body temperature were studied between -6°C and 38°C in the common pipistrelle bat Pipistrellus pipistrellus (Vespertilionidae), a European species lying close to the lower end of the mammalian size range (body mass 4.9±0.8g, N=28). Individuals maintained only occasionally a normothermic body temperature averaging 35.4±1.1°C (N=4) and often showed torpor during metabolic runs. The thermoneutral zone was found above 33°C, and basal rate of metabolism averaged 7.6±0.8mL O(2)h(-1) (N=28), which is 69% of the value predicted on the basis of body mass. Minimal wet thermal conductance was 161% of the expected value. During torpor, the rate of metabolism was related exponentially to body temperature with a Q(10) value of 2.57. Torpid bats showed intermittent ventilation, with the frequency of ventilatory cycles increasing exponentially with body temperature. Basal rate of metabolism (BMR) varied significantly with season and body temperature, but not with body mass. It was lower before the hibernation period than during the summer. The patterns observed are generally consistent with those exhibited by other vespertilionids of temperate regions. However, divergences occur with previous measurements on European pipistrelles, and the causes of the seasonal variation in BMR, which has only rarely been searched for among vespertilionids, remain to be examined.

Variation in thermal performance and reaction norms among populations of Drosophila melanogaster.

The major goal of evolutionary thermal biology is to understand how variation in temperature shapes phenotypic evolution. Comparing thermal reaction norms among populations from different thermal environments allows us to gain insights into the evolutionary mechanisms underlying thermal adaptation. Here, we have examined thermal adaptation in six wild populations of the fruit fly (Drosophila melanogaster) from markedly different natural environments by analyzing thermal reaction norms for fecundity, thorax length, wing area, and ovariole number under ecologically realistic fluctuating temperature regimes in the laboratory. Contrary to expectation, we found only minor differences in the thermal optima for fecundity among populations. Differentiation among populations was mainly due to differences in absolute (and partly also relative) thermal fecundity performance. Despite significant variation among populations in the absolute values of morphological traits, we observed only minor differentiation in their reaction norms. Overall, the thermal reaction norms for all traits examined were remarkably similar among different populations. Our results therefore suggest that thermal adaptation in D. melanogaster predominantly involves evolutionary changes in absolute trait values rather than in aspects of thermal reaction norms.