ALBERT

Description: Multilevel Monte Carlo can efficiently compute statistical estimates of discretized random variables, for a given error tolerance. Traditionally, only a certain statistic is computed from a particular implementation of multilevel Monte Carlo. This paper considers the multilevel case when one wants to verify and evaluate a single ensemble that forms an empirical approximation to many different statistics, namely an ensemble forecast. We propose a simple algorithm that, in the univariate case, allows one to derive a statistically consistent single ensemble forecast from the hierarchy of ensembles that are formed during an implementation of multilevel Monte Carlo. This ensemble forecast then allows the entire multilevel hierarchy of ensembles to be evaluated using standard ensemble forecast verification techniques. We demonstrate the case of evaluating the calibration of the forecast in this paper.

Description: The shape of Mercury, particularly when combined with its geoid, provides clues to the planet's internal structure, thermal evolution, and rotational history. Elevation measurements of the northern hemisphere acquired by the Mercury Laser Altimeter on the MESSENGER spacecraft, combined with 378 occultations of radio signals from the spacecraft in the planet's southern hemisphere, reveal the low-degree shape of Mercury. Mercury's mean radius is 2439.36±0.02 km, and there is a 0.14-km offset between the planet's centers of mass and figure. Mercury is oblate, with a polar radius 1.65 km less than the mean equatorial radius. The difference between the semimajor and semiminor equatorial axes is 1.25 km with the long axis oriented 15° west of Mercury's dynamically defined principal axis. Mercury's geoid is also oblate and elongated, but it deviates from a sphere by a factor of 10 less than Mercury's shape, implying compensation of elevation variations on a global scale.

Description: We have analyzed the Bouguer anomaly (BA) of ~1200 complex craters in the lunar highlands from Gravity Recovery and Interior Laboratory (GRAIL) observations. The BA of these craters is generally negative, though positive BA values are observed, particularly for smaller craters. Crater BA values scale inversely with crater diameter, quantifying how larger impacts produce more extensive fracturing and dilatant bulking. The Bouguer anomaly of craters larger than km in diameter is independent of crater size, indicating that there is a limiting depth to impact-generated porosity, presumably from pore collapse associated with either overburden pressure or viscous flow. Impact-generated porosity of the bulk lunar crust is likely in a state of equilibrium for craters smaller than ~30 km in diameter, consistent with an ~8-km-thick lunar megaregolith, whereas the gravity signature of larger craters is still preserved and provides new insight into the cratering record of even the oldest lunar surfaces.

Description: Insect herbivores may undergo genetic divergence on their host plants through host-associated differentiation (HAD). Much of what we know about HAD involves insect species with narrow host ranges (i.e., specialists) that spend part or all their life cycle inside their hosts, and/or reproduce asexually (e.g., parthenogenetic insects), all of which are thought to facilitate HAD. However, sexually reproducing polyphagous insects can also exhibit HAD. Few sexually reproducing insects have been tested for HAD, and when they have insects from only a handful of potential host-plant populations have been tested, making it difficult to predict how common HAD is when one considers the entire species' host range. This question is particularly relevant when considering insect pests, as host-associated populations may differ in traits relevant to their control. Here, we tested for HAD in a cotton ( Gossypium hirsutum ) pest, the cotton fleahopper (CFH) ( Pseudatomoscelis seriatus ), a sexually reproducing, highly polyphagous hemipteran insect. A previous study detected one incidence of HAD among three of its host plants. We used Amplified fragment length polymorphism (AFLP) markers to assess HAD in CFH collected from an expanded array of 13 host-plant species belonging to seven families. Overall, four genetically distinct populations were found. One genetically distinct genotype was exclusively associated with one of the host-plant species while the other three were observed across more than one host-plant species. The relatively low degree of HAD in CFH compared to the pea aphid, another hemipteran insect, stresses the likely importance of sexual recombination as a factor increasing the likelihood of HAD. Our study assesses HAD in the cotton fleahopper on 13 of its host-plant species. We found that this sexually reproducing highly polyphagous insect presents a relatively low degree of HAD across the host-plants tested. Our results stress the importance of sexual recombination as a factor decreasing the likelihood of HAD.

Description: ABSTRACT Adipose tissue-derived mesenchymal stem cells (Ad-MSC) and platelet derivatives have been used alone or in combination to achieve regeneration of injured tissues. We have tested the effect of platelet-rich plasma (PRP) on Ad-MSC and adipocyte function. PRP increased Ad-MSC viability, proliferation rate and G1- S cell cycle progression, by at least 7-, 2-, and 2.2-fold, respectively, and reduced caspase 3 cleavage. Higher PRP concentrations or PRPs derived from individuals with higher platelet counts were more effective in increasing Ad-MSC growth. PRP also accelerated cell migration by at least 1.5-fold. However, PRP did not significantly affect mature adipocyte viability, differentiation and expression levels of PPAR-γ and AP-2 mRNAs, while it increased leptin production by 3.5-fold. Interestingly, PRP treatment of mature adipocytes also enhanced the release of Interleukin (IL)-6, IL-8, IL-10, Interferon-γ and Vascular Endothelial Growth Factor. Thus, data are consistent with a stimulatory effect of platelet derivatives on Ad-MSC growth and motility. Moreover, PRP did not reduce mature adipocyte survival and increased the release of pro-angiogenic factors, which may facilitate tissue regeneration processes. This article is protected by copyright. All rights reserved

Description: The width of diffuse oceanic plate boundaries is determined by the rheology of oceanic lithosphere. Here we apply thin viscous sheet models, which have been successfully applied to deformation in several continental deforming zones, to investigate the deformation of oceanic lithosphere in the diffuse oceanic plate boundaries between the India, Capricorn, and Australia plates. We apply kinematic boundary conditions based on the current motion between these plates. We neglect buoyancy forces due to plate thinning or thickening and assume that the thin viscous sheet has the same depth-integrated non-linear viscosity coefficient everywhere. Our initial models have only one adjustable parameter, n , the power-law exponent, with n=1, 3, 10, 30, 100. The predicted width of the deforming zone decreases with increasing n , with n ≥ 30 explaining the observations. This n -value is higher than has been estimated for continental lithosphere, and suggests that more of the strength of oceanic lithosphere lies in layers deforming by faulting or by dislocation glide than for continental lithosphere. To obtain a stress field that better fits the distribution and type of earthquake focal mechanisms in the diffuse oceanic plate boundary, we add a second adjustable parameter, representing the effect of slab-pull stretching the oceanic plate near the Sumatra trench. We show that an average velocity increment on this boundary segment of 5 mm a −1 (relative to the average velocity of the India and Australia plates) fits the observed distribution of fault types better than velocities of 3.3 mm a −1 or 10 mm a −1 .

Description: This study explored the impacts of electricity allocation protocols on the life cycle greenhouse gas (GHG) emissions of electricity consumption. The selection of appropriate electricity allocation protocols, methodologies that assign pools of electricity generators to electricity consumers, has not been well standardized. This can lead to very different environmental profiles of similar, electricity-intensive processes. In an effort to better represent the interconnected nature of the U.S. electrical grid, we propose two new protocols that utilize inter-regional trade information and localized emission factors to combine generating pools that are sub- or supersets of one another. This new nested approach increases the likelihood of capturing important inter-regional electricity trading and the appropriate assignment of generator emissions to consumers of local and regional electricity. We applied the new and existing protocols to the U.S. primary aluminum industry, an industry whose environmental impact is heavily tied to its electricity consumption. Our analysis found GHG emission factors that were dramatically different than those reported in previous literature. We calculated production-weighted average emission factors of 19.0 and 19.9 kilograms carbon dioxide equivalent per kilogram of primary aluminum ingot produced when using our two nested electricity allocation protocols. Previous studies reported values of 10.5 and 11.0, at least 42% lower than those found by our study.

Description: The fundamental scientific objectives for future spacecraft exploration of Jupiter's moon Europa include confirmation of the existence of subsurface ocean beneath the surface ice shell and constraints on the physical properties of the ocean. Here we conduct a comprehensive simulation of a multiple-flyby mission. We demonstrate that radio tracking data can provide an estimate of the gravitational tidal Love number k 2 with sufficient precision to confirm the presence of a liquid layer. We further show that a capable long-range laser altimeter can improve determination of the spacecraft position, improve the k 2 determination (〈1% error), and enable the estimation of the planetary shape and Love number h 2 (3-4% error), which is directly related to the amplitude of the surface tidal deformation. These measurements, in addition to the global shape accurately constrained by the long altimetric profiles, can yield further constraints on the interior structure of Europa.

Description: An integrated life cycle assessment and life cycle cost (LCC) model was developed to compare the life cycle performance of plug-in charging versus wireless charging for an electric bus system. The model was based on a bus system simulation using existing transit bus routes in the Ann Arbor–Ypsilanti metro area in Michigan. The objective is to evaluate the LCCs for an all-electric bus system utilizing either plug-in or wireless charging and also compare these costs to both conventional pure diesel and hybrid bus systems. Despite a higher initial infrastructure investment for off-board wireless chargers deployed across the service region, the wireless charging bus system has the lowest LCC of US$0.99 per bus-kilometer among the four systems and has the potential to reduce use-phase carbon emissions attributable to the lightweighting benefits of on-board battery downsizing compared to plug-in charging. Further uncertainty analysis and sensitivity analysis indicate that the unit price of battery pack and day or night electricity price are key parameters in differentiating the LCCs between plug-in and wireless charging. Additionally, scenario analyses on battery recycling, carbon emission pricing, and discount rates were conducted to further analyze and compare their respective life cycle performance.