Universal Law for the Elastic Moduli of Solids and Structures

A law previously found for shear moduli of crystalline materials is developed and extended to all elastic moduli in solids and structures. Shear moduli were previously shown to depend only on specific volume. The bulk moduli of many materials and structures are now predicted analytically and empirically shown with unerring accuracy by observing the elasticity as a specific volume power law. The law is supported by experimental evidence from: foams, Schneebeli 2-dimensional graphene mats, metamaterials, fully dense metals, ceramics and minerals. This new, generalized, universal, elastic moduli law always describes materials that support shear stresses i.e., solids; it is shown that all elastic moduli are directly dependent only on the specific volume.Comment: 22 pages, 8 figures, 1 Table and 1 Appendi

Pharmaceutical Strategy and the Evolving Role of Merger and Acquisition

It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is the most adaptable to change. Introduction The sections in this chapter deal with a common set of topics: horizontal consolidation, merger and acquisition (M&A), advantages of size, economies of scale and scope, diversification, and industry concentration. These topics all interrelate around the fundamental issue in industrial organization: how best to organize firms and markets in order to achieve optimal economic performance? Consolidation has been rampant in most sectors of the healthcare industry since the 1980s and 1990s. Indeed, the industry was the second most active in terms of M&A activity (behind finance) between 2008 and 2009. In the pharmaceutical sector, the prior decades had been a time of growth and consolidation, as companies leveraged both size and scale in bringing drugs to market. The current landscape, however, is one of new challenges requiring new approaches to their solution. Companies are faced with internal pressures of declining pipeline productivity and compressed timelines, external pressures of patent expiry and pricing, and the uncertain implications of healthcare reform. Accompanying this evolution of challenges has been an evolution in the strategic approaches taken by pharmaceutical companies to best position themselves for success in the upcoming years

The Impact of Biomass Heat Storage on the Canopy Energy Balance and Atmospheric Stability in the Community Land Model

Atmospheric models used for weather prediction and future climate projections rely on land models to calculate surface boundary conditions. Observations of near‐surface states and fluxes made at flux measurement sites provide valuable data with which to assess the quality of simulated lower boundary conditions. A previous assessment of the Community Land Model version 4.5 using data from the Niwot Ridge Subalpine Forest AmeriFlux tower showed that simulated latent heat fluxes could be improved by adjusting a parameter describing the maximum leaf wetted area, but biases in midday sensible heat flux and nighttime momentum flux were generally not reduced by model parameter perturbations. These biases are related to the model's lack of heat storage in vegetation biomass. A biomass heat capacity is parameterized in Community Land Model version 5 with measurable quantities such as canopy height, diameter at breast height, and tree number density. After implementing a parameterization describing the heat transfer between the forest biomass and the canopy air space, the biases in the mean midday sensible heat and mean nighttime momentum fluxes at Niwot Ridge are reduced from 47 to 13 W/m2 and from 0.12 to &minus;0.03 m/s, respectively. The bias in the mean nighttime canopy air temperature was reduced from &minus;5.9 to 0.4 &deg;C. Additional simulations at other flux tower sites demonstrate a consistent reduction in midday sensible heat flux, a lower ratio of the sum of sensible and latent heat flux to net radiation, and an increase in nighttime canopy temperatures.</p

Modeling whole-tree carbon assimilation rate using observed transpiration rates and needle sugar carbon isotope ratios

• Understanding controls over plant–atmosphere CO2 exchange is important for quantifying carbon budgets across a range of spatial and temporal scales. In this study, we used a simple approach to estimate whole-tree CO2 assimilation rate (ATree) in a subalpine forest ecosystem. • We analysed the carbon isotope ratio (δ13C) of extracted needle sugars and combined it with the daytime leaf-to-air vapor pressure deficit to estimate tree water-use efficiency (WUE). The estimated WUE was then combined with observations of tree transpiration rate (E) using sap flow techniques to estimate ATree. Estimates of ATree for the three dominant tree species in the forest were combined with species distribution and tree size to estimate and gross primary productivity (GPP) using an ecosystem process model. • A sensitivity analysis showed that estimates of ATree were more sensitive to dynamics in E than δ13C. At the ecosystem scale, the abundance of lodgepole pine trees influenced seasonal dynamics in GPP considerably more than Engelmann spruce and subalpine fir because of its greater sensitivity of E to seasonal climate variation. • The results provide the framework for a nondestructive method for estimating whole-tree carbon assimilation rate and ecosystem GPP over daily-to weekly time scales

Implementation and Evaluation of a Unified Turbulence Parameterization Throughout the Canopy and Roughness Sublayer in Noah-MP Snow Simulations

The Noah-MP land surface model (LSM) relies on the Monin-Obukhov (M-O) Similarity Theory (MOST) to calculate land-atmosphere exchanges of water, energy, and momentum fluxes. However, MOST flux-profile relationships neglect canopy-induced turbulence in the roughness sublayer (RSL) and parameterize within-canopy turbulence in an ad hoc manner. We implement a new physics scheme (M-O-RSL) into Noah-MP that explicitly parameterizes turbulence in RSL. We compare Noah-MP simulations employing the M-O-RSL scheme (M-O-RSL simulations) and the default M-O scheme (M-O simulations) against observations obtained from 647 Snow Telemetry (SNOTEL) stations and two AmeriFlux stations in the western United States. M-O-RSL simulations of snow water equivalent (SWE) outperform M-O simulations over 64% and 69% of SNOTEL sites in terms of root-mean-square-error (RMSE) and correlation, respectively. The largest improvements in skill for M-O-RSL occur over closed shrubland sites, and the largest degradations in skill occur over deciduous broadleaf forest sites. Differences between M-O and M-O-RSL simulated snowpack are primarily attributable to differences in aerodynamic conductance for heat underneath the canopy top, which modulates sensible heat flux. Differences between M-O and M-O-RSL within-canopy and below-canopy sensible heat fluxes affect the amount of heat transported into snowpack and hence change snowmelt when temperatures are close to or above the melting point. The surface energy budget analysis over two AmeriFlux stations shows that differences between M-O and M-O-RSL simulations can be smaller than other model biases (e.g., surface albedo). We intend for the M-O-RSL physics scheme to improve performance and uncertainty estimates in weather and hydrological applications that rely on Noah-MP. &nbsp;</p

Modeling and Measuring the Nocturnal Drainage Flow in a High-Elevation, Subalpine Forest with Complex Terrain

The nocturnal drainage flow of air causes significant uncertainty in ecosystem CO2, H2O, and energy budgets determined with the eddy covariance measurement approach. In this study, we examined the magnitude, nature, and dynamics of the nocturnal drainage flow in a subalpine forest ecosystem with complex terrain. We used an experimental approach involving four towers, each with vertical profiling of wind speed to measure the magnitude of drainage flows and dynamics in their occurrence. We developed an analytical drainage flow model, constrained with measurements of canopy structure and SF6 diffusion, to help us interpret the tower profile results. Model predictions were in good agreement with observed profiles of wind speed, leaf area density, and wind drag coefficient. Using theory, we showed that this one‐dimensional model is reduced to the widely used exponential wind profile model under conditions where vertical leaf area density and drag coefficient are uniformly distributed. We used the model for stability analysis, which predicted the presence of a very stable layer near the height of maximum leaf area density. This stable layer acts as a flow impediment, minimizing vertical dispersion between the subcanopy air space and the atmosphere above the canopy. The prediction is consistent with the results of SF6 diffusion observations that showed minimal vertical dispersion of nighttime, subcanopy drainage flows. The stable within‐canopy air layer coincided with the height of maximum wake‐to‐shear production ratio. We concluded that nighttime drainage flows are restricted to a relatively shallow layer of air beneath the canopy, with little vertical mixing across a relatively long horizontal fetch. Insight into the horizontal and vertical structure of the drainage flow is crucial for understanding the magnitude and dynamics of the mean advective CO2 flux that becomes significant during stable nighttime conditions and are typically missed during measurement of the turbulent CO2 flux. The model and interpretation provided in this study should lead to research strategies for the measurement of these advective fluxes and their inclusion in the overall mass balance for CO2 at this site with complex terrain

Decomposing reflectance spectra to track gross primary production in a subalpine evergreen forest

Photosynthesis by terrestrial plants represents the majority of CO₂ uptake on Earth, yet it is difficult to measure directly from space. Estimation of gross primary production (GPP) from remote sensing indices represents a primary source of uncertainty, in particular for observing seasonal variations in evergreen forests. Recent vegetation remote sensing techniques have highlighted spectral regions sensitive to dynamic changes in leaf/needle carotenoid composition, showing promise for tracking seasonal changes in photosynthesis of evergreen forests. However, these have mostly been investigated with intermittent field campaigns or with narrow-band spectrometers in these ecosystems. To investigate this potential, we continuously measured vegetation reflectance (400–900 nm) using a canopy spectrometer system, PhotoSpec, mounted on top of an eddy-covariance flux tower in a subalpine evergreen forest at Niwot Ridge, Colorado, USA. We analyzed driving spectral components in the measured canopy reflectance using both statistical and process-based approaches. The decomposed spectral components co-varied with carotenoid content and GPP, supporting the interpretation of the photochemical reflectance index (PRI) and the chlorophyll/carotenoid index (CCI). Although the entire 400–900 nm range showed additional spectral changes near the red edge, it did not provide significant improvements in GPP predictions. We found little seasonal variation in both normalized difference vegetation index (NDVI) and the near-infrared vegetation index (NIRv) in this ecosystem. In addition, we quantitatively determined needle-scale chlorophyll-to-carotenoid ratios as well as anthocyanin contents using full-spectrum inversions, both of which were tightly correlated with seasonal GPP changes. Reconstructing GPP from vegetation reflectance using partial least-squares regression (PLSR) explained approximately 87 % of the variability in observed GPP. Our results linked the seasonal variation in reflectance to the pool size of photoprotective pigments, highlighting all spectral locations within 400–900 nm associated with GPP seasonality in evergreen forests

CASES-99: a comprehensive investigation of the stable nocturnal boundary layer

The Cooperative Atmosphere-Surface Exchange Study—1999 (CASES-99) refers to a field experiment carried out in southeast Kansas during October 1999 and the subsequent program of investigation. Comprehensive data, primarily taken during the nighttime but typically including the evening and morning transition, supports data analyses, theoretical studies, and state-of-the-art numerical modeling in a concerted effort by participants to investigate four areas of scientific interest. The choice of these scientific topics is motivated by both the need to delineate physical processes that characterize the stable boundary layer, which are as yet not clearly understood, and the specific scientific goals of the investigators. Each of the scientific goals should be largely achievable with the measurements taken, as is shown with preliminary analysis within the scope of three of the four scientific goals. Underlying this effort is the fundamental motivation to eliminate deficiencies in surface layer and turbulent diffusion parameterizations in atmospheric models, particularly where the Richardson number exceeds 0.25. This extensive nocturnal boundary layer (NBL) dataset is available to the scientific community at large, and the CASES-99 participants encourage all interested parties to utilize it.Carmen Nappo acknowledges the support of the U.S. Army Research Laboratory under Grant MIPROB-NOAA007. JS and SB acknowledge the support of Army Research Office Grant DAAD 1999- 1-0320, National Science Foundation Grant ATM-9906637. JC and ET acknowledge the Spanish Commission for Science and Technology through Projects CLI97-0343 and CLI99-1326- E

The Contribution of Advective Fluxes to Net Ecosystem Exchange in a High-Elevation, Subalpine Forest

The eddy covariance technique, which is used in the determination of net ecosystem CO2 exchange (NEE), is subject to significant errors when advection that carries CO2 in the mean flow is ignored. We measured horizontal and vertical advective CO2 fluxes at the Niwot Ridge AmeriFlux site (Colorado, USA) using a measurement approach consisting of multiple towers. We observed relatively high rates of both horizontal (Fhadv) and vertical (Fvadv) advective fluxes at low surface friction velocities (u*) which were associated with downslope katabatic flows. We observed that Fhadv was confined to a relatively thin layer (0–6 m thick) of subcanopy air that flowed beneath the eddy covariance sensors principally at night, carrying with it respired CO2 from the soil and lower parts of the canopy. The observed Fvadv came from above the canopy and was presumably due to the convergence of drainage flows at the tower site. The magnitudes of both Fhadv and Fvadv were similar, of opposite sign, and increased with decreasing u*, meaning that they most affected estimates of the total CO2 flux on calm nights with low wind speeds. The mathematical sign, temporal variation and dependence on u* of both Fhadv and Fvadv were determined by the unique terrain of the Niwot Ridge site. Therefore, the patterns we observed may not be broadly applicable to other sites. We evaluated the influence of advection on the cumulative annual and monthly estimates of the total CO2 flux (Fc), which is often used as an estimate of NEE, over six years using the dependence of Fhadv and Fvadv on u*. When the sum of Fhadv and Fvadv was used to correct monthly Fc, we observed values that were different from the monthly Fc calculated using the traditional u*-filter correction by -16 to 20 g C·m-2·mo-1; the mean percentage difference in monthly Fc for these two methods over the six-year period was 10%. When the sum of Fhadv and Fvadv was used to correct annual Fc, we observed a 65% difference compared to the traditional u*-filter approach. Thus, the errors to the local CO2 budget, when Fhadv and Fvadv are ignored, can become large when compounded in cumulative fashion over long time intervals. We conclude that the ‘‘micrometeorological’’ (using observations of Fhadv and Fvadv) and ‘‘biological’’ (using the u* filter and temperature vs. Fc relationship) corrections differ on the basis of fundamental mechanistic grounds. The micrometeorological correction is based on aerodynamic mechanisms and shows no correlation to drivers of biological activity. Conversely, the biological correction is based on climatic responses of organisms and has no physical connection to aerodynamic processes. In those cases where they impose corrections of similar magnitude on the cumulative Fc sum, the result is due to a serendipitous similarity in scale but has no clear mechanistic explanation