Rex E. Lee Conference on the Office of the Solicitor General of the United States: Clinton II Panel

I will say a few words about Dickerson, both because Michael has made it impossible not to and also because in some ways it represents the very best about how all of the wonderful, tried-and-true processes of the SG\u27s Office ought to work. Dickerson was very much like the other case that Michael talked about (which is one of, I think, two significant privilege controversies which the Independent Counsel laid on our doorstep). These cases may have appeared to the outside world as paradigmatically cases in which we would be hearing from the White House, or talking to the White House, or thinking about things other than the long-term institutional interests of the United States. But absolutely nothing of the sort ever happened, nor was any effort made by any political person to intrude in our decision-making policy

Modelling Pollinator and Nonpollinator Selection on Flower Colour Variation

1. Flower colour variation is ubiquitous within and between populations, which is why it has long been a focal point for studies of natural selection. This body of work has uncovered a wide range of selective agents, including pollinators, herbivores, and various abiotic factors. Nevertheless, we lack an integrative framework for predicting the phenotypic outcome in terms of floral pigmentation when these forces act collectively and often in opposition. 2. We here present such a framework through a model that incorporates selection on pigmentation at the vegetative phase (i.e., through survival to reproduction) and at the flowering phase (i.e., on pollinator attraction). We focus on anthocyanins as common class of pigments, although the model is equally applicable to any compounds that can be jointly expressed in vegetative tissue and in flowers. We explore the dynamics of our model in a theoretical context and in four scenarios based on classic systems for studying selection on flower colour. 3. Our model predicts that pollinators are the main driver for flower colour evolution, but selection on seedling survival plays a major role in the absence of pollen limitation, that is, if pollinator abundance is sufficiently high, or if pollinator preference is absent or weak (high variance in colour preference). In each of the case studies, our model recovered the predicted patterns of fitness for each floral morph given the strength and nature of selection. 4. This work suggests that selection at the vegetative phase must act alone or be exceptionally strong to negate pollinator preference for particular colours. Nevertheless, the influence of differential survival associated with anthocyanin production leaves a clear signature on the fitness curves, suggesting that nonpollinator agents of selection can often be detected from empirical data. 5. Synthesis: Overall, the application of this model to empirical systems will be key for understanding how flower colour diversity evolves and for predicting how changes in climate and pollinator communities may jointly alter evolutionary trajectories

Parametric study of prospective early commercial MHD power plants (PSPEC). General Electric Company, task 1: Parametric analysis

The performance and cost of moderate technology coal-fired open cycle MHD/steam power plant designs which can be expected to require a shorter development time and have a lower development cost than previously considered mature OCMHD/steam plants were determined. Three base cases were considered: an indirectly-fired high temperature air heater (HTAH) subsystem delivering air at 2700 F, fired by a state of the art atmospheric pressure gasifier, and the HTAH subsystem was deleted and oxygen enrichment was used to obtain requisite MHD combustion temperature. Coal pile to bus bar efficiencies in ease case 1 ranged from 41.4% to 42.9%, and cost of electricity (COE) was highest of the three base cases. For base case 2 the efficiency range was 42.0% to 45.6%, and COE was lowest. For base case 3 the efficiency range was 42.9% to 44.4%, and COE was intermediate. The best parametric cases in bases cases 2 and 3 are recommended for conceptual design. Eventual choice between these approaches is dependent on further evaluation of the tradeoffs among HTAH development risk, O2 plant integration, and further refinements of comparative costs

Caractérisation des efforts hydrodynamiques sur une maquette d'hydrolienne à axe vertical

Ce papier expose la problématique générale liée aux méthodes d'évaluation des variations spatiales et temporelles des chargements sur une maquette d'hydrolienne et à l'extraction des données issues des études hydrodynamiques, aussi bien expérimentales que numériques. Par ailleurs, nous présentons la définition détaillée d'une balance d'efforts, en cours de réalisation, destinée à la caractérisation hydrodynamiques des turbines

Lithium isotopes in large rivers reveal the cannibalistic nature of modern continental weathering and erosion

The erosion of major mountain ranges is thought to be largely cannibalistic, recycling sediments that were deposited in the ocean or on the continents prior to mountain uplift. Despite this recognition, it has not yet been possible to quantify the amount of recycled material that is presently transported by rivers to the ocean. Here, we have analyzed the Li content and isotope composition (View the MathML source) of suspended sediments sampled along river depth profiles and bed sands in three of the largest Earth's river systems (Amazon, Mackenzie and Ganga–Brahmaputra rivers). The View the MathML source values of river-sediments transported by these rivers range from +5.3 to −3.6‰ and decrease with sediment grain size. We interpret these variations as reflecting a mixture of unweathered rock fragments (preferentially transported at depth in the coarse fraction) and present-day weathering products (preferentially transported at the surface in the finest fraction). Only the finest surface sediments contain the complementary reservoir of Li solubilized by water–rock interactions within the watersheds. Li isotopes also show that river bed sands can be interpreted as a mixture between unweathered fragments of igneous and sedimentary rocks. A mass budget approach, based on Li isotopes, Li/Al and Na/Al ratios, solved by an inverse method allows us to estimate that, for the large rivers analyzed here, the part of solid weathering products formed by present-day weathering reactions and transported to the ocean do not exceed 35%. Li isotopes also show that the sediments transported by the Amazon, Mackenzie and Ganga–Brahmaputra river systems are mostly sourced from sedimentary rocks (>60%) rather than igneous rocks. This study shows that Li isotopes in the river particulate load are a good proxy for quantifying both the erosional rock sources and the fingerprint of present-day weathering processes. Overall, Li isotopes in river sediments confirm the cannibalistic nature of erosion and weathering

The Use of Hibernation Modes for Deep Space Missions as a Method to Lower Mission Operations Costs

Hibernation modes have been used in the past in the commercial and military sector under the name of ‘on-orbit storage’ or ‘onorbit spare’. Satellites that have used this technique include: METEOSAT-5 (Europe). SOOS (Navy), NOVA (Navy), GOES-10 (NOAA). These spares are used to quickly restore functionality of the system if there should be an on-orbit failure. Up until now, scientific satellites have not incorporated hibernation modes in their baseline mission timeline – though several missions used them to perform extended missions: GIOTTO and ISEE- 3/ICE. During its competitive proposal phase, CONTOUR baselined a hibernation mode as a method to reduce mission operations costs and to reduce the burden on DSN resources. CONTOUR’s hibernation mode reduces the spacecraft’s required functionality to a minimum in a power stable, thermally stable, spin stabilized attitude. The European Space Agency (ESA) Rosetta mission is also implementing a hibernation mode in its baseline mission. This paper is intended to educate the reader on the different facets of CONTOUR’s hibernation mode and issues that were taken into account during design

Convenient Synthesis of Copper (I) Thiolates and Related Compounds

Copper (I) salts of various anions including thiolates, diethyl dithiocarbamate, diethyl dithiophosphate, trithiocyanurate, 1-cyano-3-methylisothiourea, 2-aminothiazole, and tetrakis(1-imidazolyl)borate are conveniently synthesized by reducing copper (II) sulfate in aqueous ammonia. The addition of phosphine ligands to several of the products is demonstrated, and the crystal structure of [Cu2(MBT)2(DPPE)3] · Et2O (MBT = 2-mercaptobenzothiazolate, DPPE = 1,2-bis(diphenylphosphino)ethane) is reported