A preliminary synthesis of major scientific results during the SALSA program

The objective of this paper is to provide an overview of the primary results of the Semi-Arid Land-Surface-Atmosphere (SALSA) Program in the context of improvements to our overall understanding of hydrologic, ecologic, and atmospheric processes and their interactions in a semi-arid basin. The major findings and future research needs associated with the different core components of the program are emphasized. First, remote-sensing investigations are discussed, especially those directed toward taking full advantage of the capabilities of the new generation of satellites (ERS2/ATSR2, VEGETATION, LANDSAT7, NASA-EOS). Second, we discuss parameterization of the water and energy fluxes in arid and semi-arid regions, with special emphasis on methods to aggregate these fluxes from patch scale to grid scale. Third, we address the issues related to grassland ecology and competition for water between native grass and invasive mesquite species. Fourth, findings related to the interactions between surface water, ground water, and vegetation in a semi-arid riparian system are discussed. Next, an assessment of land use and land cover change over the entire basin over a quarter century is reviewed. Finally, unsolved issues and the needs for further research are outlined

A generalized approach for computation of near field radiation pattern of an antenna

A generalized procedure in the form of an analytical formulation for the determination of radiation pattern of an antenna at any arbitrary distance which covers the near field as well as far field is presented in this paper. With the prior knowledge of either the current or field distribution on the radiating aperture, the proposed near field analysis is generic and can be applied for wide variety of antenna elements. The underlying principle of the generalized procedure is tantamount to considering the radiating aperture as an array of point electric and magnetic dipoles. The validity and novelty of the proposed new approach have been substantiated considering an open ended circular cylindrical waveguide and a conical horn as case studies and treating the far field as a special case of near field with pertinent distance criterion. The effect of change in the distance of observation ranging from reactive near field to far field on the radiation patterns of these antennas has also been discussed. The simulation studies reveal that the depicted normalized phase patterns of both the circular waveguide and conical horn follow the changes in the profile of the corresponding amplitude patterns

2-Pyridyl substituents enhance the activity of palladium-phospha-adamantane catalysts for the methoxycarbonylation of phenylacetylene

The pyridyl-N in Pt and Pd complexes of CgP(2-py) can be protonated or can coordinate to form a P,N-chelate; these features are linked with the carbonylation catalysis results.</p

Identification of high performance solvents for the sustainable processing of graphene

Nanomaterials have many advanced applications, from bio-medicine to flexible electronics to energy storage, and the broad interest in graphene-based materials and devices means that high annual tonnages will be required to meet this demand. However, manufacturing at the required scale remains unfeasible until economic and environmental obstacles are resolved. Liquid exfoliation of graphite is the preferred scalable method to prepare large quantities of good quality graphene, but only low concentrations are achieved and the solvents habitually employed are toxic. Furthermore, good dispersions of nanomaterials in organic solvents are crucial for the synthesis of many types of nanocomposites. To address the performance and safety issues of solvent use, a bespoke approach to solvent selection was developed and the renewable solvent Cyrene was identified as having excellent properties. Graphene dispersions in Cyrene were found to be an order of magnitude more concentrated than those achieved in N-methylpyrrolidinone (NMP). Key attributes to this success are optimum solvent polarity, and importantly a high viscosity. We report the role of viscosity as crucial for the creation of larger and less defective graphene flakes. These findings can equally be applied to the dispersion of other layered bi-dimensional materials, where alternative solvent options could be used as drop-in replacements for established processes without disruption or the need to use specialized equipment. Thus, the discovery of a benign yet high performance graphene processing solvent enhances the efficiency, sustainability and commercial potential of this ever-growing field, particularly in the area of bulk material processing for large volume applications

The South American Land Data Assimilation System (SALDAS) 5-Year Retrospective Atmospheric Forcing Datasets

The definition and derivation of a 5-year, 0.125deg, 3-hourly atmospheric forcing dataset for the South America continent is described which is appropriate for use in a Land Data Assimilation System and which, because of the limited surface observational networks available in this region, uses remotely sensed data merged with surface observations as the basis for the precipitation and downward shortwave radiation fields. The quality of this data set is evaluated against available surface observations. There are regional difference in the biases for all variables in the dataset, with biases in precipitation of the order 0-1 mm/day and RMSE of 5-15 mm/day, biases in surface solar radiation of the order 10 W/sq m and RMSE of 20 W/sq m, positive biases in temperature typically between 0 and 4 K, depending on region, and positive biases in specific humidity around 2-3 g/Kg in tropical regions and negative biases around 1-2 g/Kg further south

Revisiting the contribution of transpiration to global terrestrial evapotranspiration

Even though knowing the contributions of transpiration (T), soil and open water evaporation (E), and interception (I) to terrestrial evapotranspiration (ET=T+E+I) is crucial for understanding the hydrological cycle and its connection to ecological processes, the fraction of T is unattainable by traditional measurement techniques over large scales. Previously reported global mean T/(E+T+I) from multiple independent sources, including satellite-based estimations, reanalysis, land surface models, and isotopic measurements, varies substantially from 24% to 90%. Here we develop a new ET partitioning algorithm, which combines global evapotranspiration estimates and relationships between leaf area index (LAI) and T/(E+T) for different vegetation types, to upscale a wide range of published site-scale measurements. We show that transpiration accounts for about 57.2% (with standard deviation6.8%) of global terrestrial ET. Our approach bridges the scale gap between site measurements and global model simulations,and can be simply implemented into current global climate models to improve biological CO2 flux simulations

Polysaccharide-derived mesoporous materials (Starbon®) for sustainable separation of complex mixtures

The recovery and separation of high value and low volume extractives are a considerable challenge for the commercial realisation of zero-waste biorefineries. Using solid-phase extractions (SPE) based on sustainable sorbents is a promising method to enable efficient, green and selective separation of these complex extractive mixtures. Mesoporous carbonaceous solids derived from renewable polysaccharides are ideal stationary phases due to their tuneable functionality and surface structure. In this study, the structure-separation relationships of thirteen polysaccharide-derived mesoporous materials and two modified types as sorbents for ten naturally-occurring bioactive phenolic compounds were investigated. For the first time, a comprehensive statistical analysis of the key molecular and surface properties influencing the recovery of these species was carried out. The obtained results show the possibility of developing tailored materials for purification, separation or extraction, depending on the molecular composition of the analyte. The wide versatility and application span of these polysaccharide-derived mesoporous materials offer new sustainable and inexpensive alternatives to traditional silica-based stationary phases

Mutational activation of BRAF confers sensitivity to transforming growth factor beta inhibitors in human cancer cells

Recent data implicate elevated transforming growth factor-β (TGFβ) signalling in BRAF inhibitor drug-resistance mechanisms, but the potential for targeting TGFβ signalling in cases of advanced melanoma has not been investigated. We show that mutant BRAFV600E confers an intrinsic dependence on TGFβ/TGFβ receptor 1 (TGFBR1) signalling for clonogenicity of murine melanocytes. Pharmacological inhibition of the TGFBR1 blocked the clonogenicity of human mutant BRAF melanoma cells through SMAD4-independent inhibition of mitosis, and also inhibited metastasis in xenografted zebrafish. When investigating the therapeutic potential of combining inhibitors of mutant BRAF and TGFBR1, we noted that unexpectedly, low-dose PLX-4720 (a vemurafenib analogue) promoted proliferation of drug-naïve melanoma cells. Pharmacological or pharmacogenetic inhibition of TGFBR1 blocked growth promotion and phosphorylation of SRC, which is frequently associated with vemurafenib-resistance mechanisms. Importantly, vemurafenib-resistant patient derived cells retained sensitivity to TGFBR1 inhibition, suggesting that TGFBR1 could be targeted therapeutically to combat the development of vemurafenib drug-resistance

The projection and measurement of cyberpower

Cyberspace and cyberpower are terms that are increasingly used in common parlance, but are notoriously difficult to define and measure. This article builds on previous work defining the properties of cyberspace in terms of vertical layers, which when combined with a representation of distance presents a three-dimensional model. The unique attributes of cyberspace can be harnessed for power projection, the aim of which is ultimately to alter the behaviour of individuals. Although cyberspace has yet to be used as a medium to demonstrate conventional hard power of coercion and threats supported by physical force, it does present a suitable medium for the projection of soft power of attraction and imitation. These are defined within the context of the online environment and by drawing on the techniques used to optimise Web-based commerce, potential methods of implementing and measuring the success of a campaign of cyberpower projection are proposed

The Maine State House: A Brief History and Guide

This is a building for all the people of Maine, which also welcomes visitors to the state who wish to share in this expression of our heritage.https://digitalcommons.usm.maine.edu/mhpc-docs/1005/thumbnail.jp