We present results from MMT/Hectochelle spectroscopy of 390 red giant candidate stars along the line of sight to the recently discovered Galactic satellite Crater 2. Modeling the joint distribution of stellar positions, velocities, and metallicities as a mixture of Crater 2 and Galactic foreground populations, we identify similar to 62 members of Crater 2, for which we resolve a line-of-sight velocity dispersion of sigma(nu los) = 2.7(-0.3)(+0.3) km s(-1) and a. mean velocity of <nu(los)> = 87.5(-0.4)(+0.4) km s(-1) (solar rest frame). We also resolve a metallicity dispersion of sigma([Fe/H]) = 0.22(-0.03)(+0.04) dex and a mean of <[Fe/H]> = 1.98(-0.1)(+0.1) dex that is 0.28 +/- 0.14 dex poorer than estimated from photometry. Despite Crater 2's relatively large size (projected halflight radius R-h similar to 1 kpc) and intermediate luminosity (M-V similar to -8), its velocity dispersion is the coldest that has been resolved for any dwarf galaxy. These properties make Crater 2 the most extreme low-density outlier in dynamical as well as structural scaling relations among the Milky Way's dwarf spheroidals. Even so, under assumptions of dynamical equilibrium and negligible contamination by unresolved binary stars, the observed velocity distribution implies a gravitationally dominant dark matter halo, with a dynamical mass of. 4.4(-0.9)(+1.2) x 10(6) M-circle dot and a mass-to-light ratio of 53(-11)(+15) M-circle dot/L-V,L-circle dot enclosed within a radius of similar to 1 kpc, where the equivalent circular velocity is 4.3(-0.5)(+0.5) km s(-1).

We present VIMOS-Very Large Telescope (VLT) spectroscopy of the Frontier Fields cluster MACS. J0416.1-2403 (z = 0.397). Taken as part of the CLASH-VLT survey, the large spectroscopic campaign provided more than 4000 reliable redshifts over similar to 600 arcmin(2), including similar to 800 cluster member galaxies. The unprecedented sample of cluster members at this redshift allows us to perform a highly detailed dynamical and structural analysis of the cluster out to similar to 2.2 r(200) (similar to 4Mpc). Our analysis of substructures reveals a complex system composed of a main massive cluster (M-200 similar to 0.9 x 10(15) M-circle dot and sigma(V r200) similar to 1000 km s(-1)) presenting two major features: (i) a bimodal velocity distribution, showing two central peaks separated by Delta V-rf similar to 1100 km s(-1) with comparable galaxy content and velocity dispersion, and (ii) a projected elongation of the main substructures along the NE-SW direction, with a prominent sub-clump similar to 600 kpc SW of the center and an isolated BCG approximately halfway between the center and the SW clump. We also detect a low-mass structure at z similar to 0.390, similar to 10' south of the cluster center, projected at similar to 3Mpc, with a relative line-of-sight velocity of Delta V-rf similar to 1700 km s(-1). The cluster mass profile that we obtain through our dynamical analysis deviates significantly from the "universal" NFW, being best fit by a Softened Isothermal Sphere model instead. The mass profile measured from the galaxy dynamics is found to be in relatively good agreement with those obtained from strong and weak lensing, as well as with that from the X-rays, despite the clearly unrelaxed nature of the cluster. Our results reveal an overall complex dynamical state of this massive cluster and support the hypothesis that the two main subclusters are being observed in a pre-collisional phase, in agreement with recent findings from radio and deep X-ray data. In this article, we also release the entire redshift catalog of 4386 sources in the field of this cluster, which includes 60 identified Chandra X-ray sources and 105 JVLA radio sources.

We motivate the importance of understanding the kinematics and dynamics of the Milky Way stellar halo both in unravelling the formation history and evolution of our host Galaxy and in the more general context of galaxy dynamics. We present a cleaned picture of the kinematics of the smooth component of the stellar halo: we develop a method to quantify the average distance error on a sample of stars based on the idea of Schoenrich et al. (2012), but adapted so that it uses velocity information only on average. We use this scheme to construct an analytic distance calibration for Blue Horizontal Branch (BHB) field halo stars in Sloan colours and demonstrate that our calibration is a) more accurate than the ones available and b) unbiased w.r.t. metallicity and colour. We measure the rotation of the smooth component of the stellar halo with a tool-set of four estimators that use either only the l.o.s. velocities or the full 3D motion. From two samples of BHB stars from the Sloan Digital Sky Survey, we favour a non-rotating single halo. We critique conflicting results in the literature based on similar samples and trace back the disagreement (either in the sign of rotation or in the morphology of the halo) to sample contaminations and/or neglect account of the halo geometry. We propose a scheme that generalizes any isotropic spherical model to a model where the potential is axisymmetric and the distribution function is a function of the three actions. The idea is to approximate the Hamiltonian as a function of the actions with a library of quadratic fits to surfaces of constant energy in action space and then make explicit the dependence of the energy on the three actions in the ergodic distribution function. The transparency of the physics implied by the model we achieve, should make it possible to combine our spheroidal models to the f(J)-models of Binney (2010) for the disks and of Pontzen & Governato (2013) for the dark-matter halo, and obtain a complete actions-defined dynamical model of the Milky Way Galaxy.

Empirical knowledge is lacking on reclined seating postures. To unify such data, a biomechanical model is needed that accurately predicts posture, the relative position of the pelvis, the point of load transfer to the seat, internal and external forces, and the motion paths of the support surfaces. The overall aim of this investigation was, therefore, to create and validate a biomechanical model of reclined seating postures, and to evaluate in vivo measured and predicted data. A two-dimensional biomechanical model was developed, validated and applied. A comprehensive set of biomechanical data was collected from fifteen gender and age diverse subjects to examine the foundational principles for reclined seating ergonomics. The model agreed with 98.8% of measured data on posture across the seated test conditions. There was a significant relationship between modelled and measured force (p < .001, r = .92), which improved after normalisation (p < .001, r = .97) with an 8% full scale error. The model was robust across height and gender. Significant differences in interface pressure (peak pressure, average pressure and area), stature, back muscle activity and spinal curvature were found between all of the seated test postures. Significant relationships were found between the model predictions and all of the experimental data. This research is unique in creating a framework around reclined seating postures which connects previously disparate areas of seating research. The biomechanical model, experimental results, and theories developed from this research have potential implications in research, and design, for applications including backcare chairs, seating for long-term care and patients with neuromotor deficits, wheelchairs and airline seating. Furthermore, this study exists at the interface of anthropometric and biomechanical modelling, and therefore may have cross over potential to digital humans, where their integration with biomechanical models is at the cutting edge of the field.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Computational models of musculoskeletal joints and limbs can provide useful information about joint mechanics. Validated models can be used as a predictive device for understanding joint function and serve as a clinical tool for predicting the outcome of surgical procedures. A new computational modeling approach was developed for simulating joint kinematics that are dictated by bone/joint anatomy, ligamentous constraints, and applied loading.Three-dimensional computational models of the lower leg were created. Model development involved generating three-dimensional surfaces from CT images, followed by importing these surfaces into SolidWorks and COSMOSMotion. ThroughSolidWorks and COSMOSMotion, each bone surface was created into a solid object and positioned, necessary components added, and simulations executed. Three dimensional contacts inhibited intersection of the bones during motion. Ligaments were represented as linear springs. Model predictions were then validated by comparison to three different previously performed cadaver studies (syndesmotic injury study, inversion stability study, and mechanical laxity study) and one simultaneously performed cadaver study (anterior drawer test).In the syndesmotic injury study, the relative motion between the tibia and fibula in intact, transected, and repaired states was measured under the application of an external rotation of the ankle. The inversion stability study focused on the elongation behavior of lateral ankle ligaments and inversion range of motion during the application of an applied load. The mechanical laxity study focused on differences in anterior/posterior and inversion/eversion movement in intact and transected states. Each computational simulation was placed under the same conditions as its respective cadaver study and revealed a capability to predict behaviors in each case. The syndesmotic injury model was able to predict tibia1 rotation, fibular rotation, and anterior/posterior displacement. In the inversion simulation, calcaneofibular ligament extension and angles of inversion compared well. The laxity study showed increases in anteroposter motion after the transactions of the ATFL and CFL; and diffenences in inversion after the transaction of the CFL. The Anterior Drawer simulation produced similar ligament elongations and loads when compared to cadaver studies.Overall, the computational models were able to predict joint kinematics of the lower leg with particular focus on the ankle complex. Additional parameters can be calculated through such models that are not easily obtained experimentally such as ligament forces, force transmission across joints, and three-dimensional movement of all bones.

Introduction: It has been proposed that inadequate rest intervals may contribute to decreased performance of activities. However, previous research has not investigated the effect of rest interval on performance of the Star Excursion Balance Test (SEBT) in individuals with and without chronic ankle instability. Objective: To determine whether rest interval affects performance of the SEBT associated with chronic ankle instability (CAI) and whether neuromuscular function, postural control or biomechanics can be associated factors which may help discriminate between healthy individuals and those with CAI during the SEBT. Design: 2-group counterbalanced study. Participants: Participants included 24 individuals with a history of at least one ankle sprain in the past year and at least 2 episodes of giving way in the past 6 month prior to study enrollment, and 24 individuals with no history of ankle sprain or instability in their lifetime. Methods: Subjects completed 3 trials in each of the 3 reach directions (anteromedial, medial, posteromedial) in random order. A total of three visits were required in order to complete the 3 rest intervals (10, 20, 40 seconds). Normalized maximum reach distance, electromyographic (EMG) activation of tibialis anterior, peroneus longus, and medial gastrocnemius muscles, multiplanar motion of the lower extremity, coupling angles (CA) of lower extremity segments and maximum lateral center of pressure velocity were calculated and compared between groups in each direction for each rest interval. Results: Rest interval did not influence differences of reach distance, EMG ankle muscle activation, kinematics and center of pressure velocity between healthy individuals and those with CAI during the SEBT. However, the rest interval of 20 seconds demonstrated differences in CAs of tibial internal rotation/dorsiflexion (TIR/DF) and tibial internal rotation/eversion (TIR/EV) between healthy individuals and those with CAI during the SEBT. Overall, reach distance, mean amplitude of EMG ankle muscles, kinematics and joint CAs were different between healthy individuals and those with CAI during the SEBT regardless of rest interval. Discussion: Based on these results, differences exist in neuromuscular functions and biomechanics between healthy individuals and those with CAI when performing the SEBT. A rest interval time of 20 seconds between trials during the SEBT is an appropriate time to discriminate joint CAs of TIR/DF and TIR/EV between healthy individuals and those with CAI during the SEBT. These findings have implications for treatment and possible prevention of CAI.

We present a multiwavelength investigation of a region of a nearby giant molecular cloud that is distinguished by a minimal level of star formation activity. With our new (CO)-C-12(J = 2-1) and (CO)-C-13(J = 2-1) observations of a remote region within the middle of the California molecular cloud, we aim to investigate the relationship between filaments, cores, and a molecular outflow in a relatively pristine environment. An extinction map of the region from Herschel Space Observatory observations reveals the presence of two 2 pc long filaments radiating from a highextinction clump. Using the (CO)-C-13 observations, we show that the filaments have coherent velocity gradients and that their mass-per-unit-lengths may exceed the critical value above which filaments are gravitationally unstable. The region exhibits structure with eight cores, at least one of which is a starless, prestellar core. We identify a low-velocity, low-mass molecular outflow that may be driven by a flat spectrum protostar. The outflow does not appear to be responsible for driving the turbulence in the core with which it is associated, nor does it provide significant support against gravitational collapse.

We present Gemini Planet Imager polarized intensity imagery of HD 100453 in Y, J, and K1 bands that reveals an inner gap (9-18 au), an outer disk (18-39 au) with two prominent spiral arms, and two azimuthally localized dark features that are also present in Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) total intensity images. Spectral energy distribution fitting further suggests that the radial gap extends to 1 au. The narrow, wedge-like shape of the dark features appears similar to predictions of shadows cast by an inner disk that is misaligned with respect to the outer disk. Using the Monte Carlo radiative transfer code HOCHUNCK3D, we construct a model of the disk that allows us to determine its physical properties in more detail. From the angular separation of the features, we measure the difference in inclination between the disks (45 degrees) and their major axes, PA = 140 degrees east of north for the outer disk, and 100 degrees for the inner disk. We find an outer-disk inclination of 25 degrees +/- 10 degrees from face-on, in broad agreement with the Wagner et al. measurement of 34 degrees. SPHERE data in J and H bands indicate a reddish disk, which indicates that HD 100453 is evolving into a young debris disk.

Title: Influence of the breathing muscles using POWERbreathe. Objective: The main object of this thesis is to determine, if it is possible to use 3D kinematic analysis to measure changes of trunk shapes during quiet breathing and breathing when using POWERbreathe and if it is possible to identify the changes. The thesis is divided to two parts. The first part contains theoretical part, focused on issue of kinesiology and biomechanics of breathing. The special part is concentrated on research, where I find changes of trunk kinematics during application of POWERbreathe. Method: Measurements were made on 6 probands in the same age category (women), when each measurement was performed during quiet breathing, maximum inhale/exhale, resistive breathing when using POWERbreathe and then another quiet breathing and maximum inhale/exhale. Quiet breathing was chosen as benchmark. The experimental measurements was done during one day. The research was used 3D kinematic motion analysis using system Qualysis. Were observed changes in the shape of the trunk and possibly caused breath changes during using POWERbreathe. Results: Measurements has confirmed, that the system Qualysis is able to detect mobility and the trunk shape changes. At a certain threshold load device POWERbreathe prevailed movements cranial...