Live Fast, Die Young: GMC lifetimes in the FIRE cosmological simulations of Milky Way-mass galaxies

We present the first measurement of the lifetimes of giant molecular clouds (GMCs) in cosmological simulations at z = 0, using the Latte suite of FIRE-2 simulations of Milky Way (MW) mass galaxies. We track GMCs with total gas mass ≳10⁵ M⊙ at high spatial (∼1 pc), mass (7100 M⊙), and temporal (1 Myr) resolution. Our simulated GMCs are consistent with the distribution of masses for massive GMCs in the MW and nearby galaxies. We find GMC lifetimes of 5–7 Myr, or 1–2 freefall times, on average, with less than 2 per cent of clouds living longer than 20 Myr. We find decreasing GMC lifetimes with increasing virial parameter, and weakly increasing GMC lifetimes with galactocentric radius, implying that environment affects the evolutionary cycle of GMCs. However, our GMC lifetimes show no systematic dependence on GMC mass or amount of star formation. These results are broadly consistent with inferences from the literature and provide an initial investigation into ultimately understanding the physical processes that govern GMC lifetimes in a cosmological setting

Balloon dilatation of the eustachian tube for obstructive eustachian tube dysfunction in adults

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows: To evaluate the effects of balloon dilatation of the Eustachian tube in adults with obstructive Eustachian tube dysfunction

Growth dynamics of a Bose-Einstein condensate in a dimple trap without cooling

We study the formation of a Bose-Einstein condensate in a cigar-shaped three-dimensional harmonic trap, induced by the controlled addition of an attractive "dimple" potential along the weak axis. In this manner we are able to induce condensation without cooling due to a localized increase in the phase space density. We perform a quantitative analysis of the thermodynamic transformation in both the sudden and adiabatic regimes for a range of dimple widths and depths. We find good agreement with equilibrium calculations based on self-consistent semiclassical Hartree-Fock theory describing the condensate and thermal cloud. We observe there is an optimal dimple depth that results in a maximum in the condensate fraction. We also study the non-equilibrium dynamics of condensate formation in the sudden turn-on regime, finding good agreement for the observed time dependence of the condensate fraction with calculations based on quantum kinetic theory.Comment: v1: 9 pages, 7 figures, submitted to Phys. Rev. A; v2: 10 pages, 8 figures, fixed typos, added references, additional details on experimental procedure, values of phase-space density, new figure and discussion on effects of three-body loss in Appendix B (replaced with published version

Real-Reward Testing for Probabilistic Processes (Extended Abstract)

We introduce a notion of real-valued reward testing for probabilistic processes by extending the traditional nonnegative-reward testing with negative rewards. In this richer testing framework, the may and must preorders turn out to be inverses. We show that for convergent processes with finitely many states and transitions, but not in the presence of divergence, the real-reward must-testing preorder coincides with the nonnegative-reward must-testing preorder. To prove this coincidence we characterise the usual resolution-based testing in terms of the weak transitions of processes, without having to involve policies, adversaries, schedulers, resolutions, or similar structures that are external to the process under investigation. This requires establishing the continuity of our function for calculating testing outcomes.Comment: In Proceedings QAPL 2011, arXiv:1107.074

Memory enhancement produced by post-training exposure to sucrose-conditioned cues

A number of aversive and appetitive unconditioned stimuli (such as shock and food) are known to produce memory enhancement when they occur during the post-training period. Post-training exposure to conditioned aversive stimuli has also been shown to enhance memory consolidation processes. The present study shows for the first time that post-training exposure to conditioned stimuli previously paired with consumption of a sucrose solution also enhances memory consolidation. Male Long Evans rats were trained on a one-session conditioned cue preference (CCP) task on a radial arm maze. Immediately or 2 hours after training, rats consumed a sucrose solution or were exposed to cues previously paired with consumption of sucrose or cues previously paired with water. Twenty-four hours later, the rats were tested for a CCP. Immediate, but not delayed, post-training consumption of sucrose enhanced memory for the CCP. Immediate, but not delayed, post-training exposure to cues previously paired with sucrose, but not with water, also enhanced CCP memory. The possibility that rewarding and aversive conditioned stimuli affect memory by a common physiological process is discussed

Cilia Have a Significant Role in Regulating Cell Size in Response to Fluid Flow Induced Shear Stress in a Flow Chamber

Cilia are hair-like protrusions on the apical surface of cells. Their function is to relay mechanical signals like shear stress from extracellular into intracellular environment and thereby maintain cellular homeostasis. Ciliary dysfunctions include polycystic kidney disease and new therapeutic interventions based on ciliary function are under investigation. The current study evaluates the use of a custom designed fluid flow chamber’s ability to study the role of cilia in regulating cell size in response to shear stress. A fluid flow chamber that continually maintains laminar flow at different flow rates and temperature was designed. Endothelial wild type cells (ETWT) that have cilia and polycystic kidney disease cells (PKD) that lost their ciliary function are grown on different glass slides. Cells on each glass slide are then exposed to continuous flow of phosphate-buffered saline at 37oC in the flow chamber. The optimal flow rate and duration of flow were first determined by measuring the total protein concentration before and after exposing the cells. Cell radius and area before and after exposing them to flow are measured using the NIS Software available on the microscope. The results from protein concentrations (n=12) indicate that cells are still attached at normal physiological flow rate 467 mL/min (2.8 µg/µL) and did not significantly differ from 60 mL/min (4.08 µg/µL) or 600 mL/min (2.73 µg/µL). The results for duration of fluid flow (n=22) show that 60 minutes (0.09 + 0.01 µg/µL) is optimal compared to 120 minutes (0.06 + 0.01 µg/µL) or 180 minutes (0.10 + 0.02 µg/µL). Under these optimal conditions, the average area of ETWT cells (n=300) measured from different slides before and after the flow is 4420.81+ 67.40 µm2 and 4678.17 + 87.15 µm2 (n=200) respectively. For PKD cells, the average area before and after the flow (n=300) is 5682.46 + 105.48 µm2 and 4173.74 + 263.97 µm2 (n=250). These results are in agreement with the published literature on the ability of cilia to maintain cell size in ETWT cells in response to shear stress that is similar to normal blood flow. However, under similar conditions, PKD cells could not maintain their cell size as the mechano-chemical signaling pathway that communicates external signals to prepare appropriate intracellular response is disrupted. These results provide confirmation that the custom designed parallel plate fluid flow chamber is a reliable tool to investigate the specific targets in the mechano-chemical cell signaling pathways

Review of US GO-SHIP (Global Oceans Shipboard Hydrographic Investigations Program) An OCB and US CLIVAR Report

The following document constitutes a review of the US GO-SHIP program, performed under the auspices of US Climate Variability and Predictability (CLIVAR) and Ocean Carbon Biogeochemistry (OCB) Programs. It is the product of an external review committee, charged and assembled by US CLIVAR and OCB with members who represent the interests of the programs and who are independent of US GO-SHIP support, which spent several months gathering input and drafting this report. The purpose of the review is to assess program planning, progress, and opportunities in collecting, providing, and synthesizing high quality hydrographic data to advance the scientific research goals of US CLIVAR and OCB

Dynamical tunnelling with ultracold atoms in magnetic microtraps

The study of dynamical tunnelling in a periodically driven anharmonic potential probes the quantum-classical transition via the experimental control of the effective Planck's constant for the system. In this paper we consider the prospects for observing dynamical tunnelling with ultracold atoms in magnetic microtraps on atom chips. We outline the driven anharmonic potentials that are possible using standard magnetic traps, and find the Floquet spectrum for one of these as a function of the potential strength, modulation, and effective Planck's constant. We develop an integrable approximation to the non-integrable Hamiltonian and find that it can explain the behaviour of the tunnelling rate as a function of the effective Planck's constant in the regular region of parameter space. In the chaotic region we compare our results with the predictions of models that describe chaos-assisted tunnelling. Finally we examine the practicality of performing these experiments in the laboratory with Bose-Einstein condensates.Comment: V1: 12 pages, 10 figures. V2: 14 pages, 12 figures, significantly updated in response to referee report. Some figures are lower quality to reduce file sizes, please contact submitter for high quality versions. V3: Introduction rewritten, but mostly unchanged; updated to published versio

Human Model Reaching, Grasping, Looking and Sitting Using Smart Objects

Manually creating convincing animated human motion in a 3D ergonomic test environment is tedious and time consuming. However, procedural motion generators help animators efficiently produce complex and realistic motions. Using the concept of a Human Modeling Software Testbed (HMST), we created novel procedural methods for animating reaching, grasping, looking, and sitting using the environmental context of ‘smart’ objects that parametrically guide human model ergonomic motions. This approach enabled complicated procedures such as collision-free leg reach and contextual sitting motion generation. By procedurally adding small secondary details to the animation, such as head/eye vision constraints and prehensile grasps, the animated motions look more natural with minimal animator input. A ‘smart’ object in the scene graph provides specific parameters to produce proper motions and final positions. These parameters are applied to the desired figure procedurally to create any secondary motions, and further generalize to any environment. Our system allows users to proceed with any required ergonomic analyses with confidence in the visual validity of the automated motions