Phosphorus and arsenic distributions in a seasonally-stratified, iron- and manganese-rich lake: microbiological and geochemical controls

Seasonal stratification in temperate lakes greater than a few metres deep provides conditions amenable to pronounced vertical zonation of redox chemistry. Such changes are particularly evident in eutrophic systems where high phytoplankton biomass often leads to seasonally-established anoxic hypolimnia and profound changes in geochemical conditions. In this study, we investigated the behaviour of trace elements in the water column of a seasonally-stratified, eutrophic lake. Two consecutive years of data from Lake Ngapouri, North Island, New Zealand, demonstrate the occurrence of highly correlated profiles of phosphorus (P), arsenic (As), iron (Fe) and manganese (Mn), all of which increased in concentration by 1-2 orders of magnitude within the anoxic hypolimnion. Stoichiometric and mass-balance considerations demonstrate that increases in alkalinity in hypolimnetic waters were consistent with observed changes in sulfate, Fe and Mn concentrations with depth, corresponding to dissimilatory reduction of sulfate, Fe(III) and Mn(IV) hydroxides. Thermodynamic constraints on Fe, Mn and Al solubility indicate that amorphous Fe(III), Mn(IV) hydroxides most probably controlled Fe and Mn in the surface mixed layer (~0 to 8 m) while Al(III) hydroxides were supersaturated throughout the entire system. Surface complexation modelling indicated that iron hydroxides (HFO) potentially dominated As speciation in the lake. It is likely that other colloidal phases such as allophanic clays also limited HPO42- activity, reducing competition for HAsO42- adsorption to iron hydroxides. This research highlights the coupling of P, As, Fe and Mn in Lake Ngapouri, and the apparent role of multiple colloidal phases in affecting P and As activity within overarching microbiological and geochemical processes

Effects of GATT/WTO on Asia's Trade Performance

Our review of the literature suggests that the effects of GATT/WTO are insignificant or relatively small for participants in general, but potentially very large for groups that make heavy use of it. Our empirical analysis suggests that these gains are disproportionately large for the Asia-Pacific countries—perhaps by reducing resistance to the rapid growth and change in trade patterns in the region. We also highlight a potentially important source of future gains through helping to restrain the costly growth of agricultural protection in rapidly-developing countries in the region.Asian trade growth, GATT commitments, WTO accession

Study of the Pioneer Anomaly: A Problem Set

Analysis of the radio-metric tracking data from the Pioneer 10 and 11 spacecraft at distances between 20--70 astronomical units from the Sun has consistently indicated the presence of an anomalous, small, and constant Doppler frequency drift. The drift is a blue-shift, uniformly changing at the rate of (5.99 +/- 0.01) x 10^{-9} Hz/s. The signal also can be interpreted as a constant acceleration of each particular spacecraft of (8.74 +/- 1.33) x 10^{-8} cm/s^2 directed toward the Sun. This interpretation has become known as the Pioneer anomaly. We provide a problem set based on the detailed investigation of this anomaly, the nature of which remains unexplained.Comment: 14 pages, 3 figures, 5 tables, minor corrections before publicatio

Anderson et al. Reply (to the Comment by Murphy on Pioneer 10/11)

We conclude that Murphy's proposal (radiation of the power of the main-bus electrical systems from the rear of the craft) can not explain the anomalous Pioneer acceleration.Comment: LaTex, 3 pages, Phys. Rev. Lett. (to be published

Anderson et al. Reply (to the Comment by Katz on Pioneer 10/11)

We conclude that Katz's proposal (anisotropic heat reflection off of the back of the spacecraft high-gain antennae, the heat coming from the RTGs) does not provide enough power and so can not explain the Pioneer anomaly.Comment: LaTex, 3 pages, Phys. Rev. Lett. (to be published

Thermodynamic identities and particle number fluctuations in weakly interacting Bose--Einstein condensates

We derive exact thermodynamic identities relating the average number of condensed atoms and the root-mean-square fluctuations determined in different statistical ensembles for the weakly interacting Bose gas confined in a box. This is achieved by introducing the concept of {\it auxiliary partition functions} for model Hamiltonians that do conserve the total number of particles. Exploiting such thermodynamic identities, we provide the first, completely analytical prediction of the microcanonical particle number fluctuations in the weakly interacting Bose gas. Such fluctuations, as a function of the volume V of the box are found to behave normally, at variance with the anomalous scaling behavior V^{4/3} of the fluctuations in the ideal Bose gas.Comment: 5 pages, 1 figur

The Apparent Anomalous, Weak, Long-Range Acceleration of Pioneer 10 and 11

Recently we reported that radio Doppler data generated by NASA's Deep Space Network (DSN) from the Pioneer 10 and 11 spacecraft indicate an apparent anomalous, constant, spacecraft acceleration with a magnitude $\sim 8.5\times 10^{-8}$ cm s$^{-2}$, directed towards the Sun (gr-qc/9808081). Analysis of similar Doppler and ranging data from the Galileo and Ulysses spacecraft yielded ambiguous results for the anomalous acceleration, but it was useful in that it ruled out the possibility of a systematic error in the DSN Doppler system that could easily have been mistaken as a spacecraft acceleration. Here we present some new results, including a critique suggestions that the anomalous acceleration could be caused by collimated thermal emission. Based partially on a further data for the Pioneer 10 orbit determination, the data now spans January 1987 to July 1998, our best estimate of the average Pioneer 10 acceleration directed towards the Sun is $\sim 7.5 \times 10^{-8}$ cm s$^{-2}$.Comment: Latex, 7 pages and 2 figures. Invited talk at the XXXIV-th Rencontres de Moriond Meeting on Gravitational Waves and Experimental Gravity. Les Arcs, Savoi, France (January 23-30,1999). Corrected typo

Modular Equations and Distortion Functions

Modular equations occur in number theory, but it is less known that such equations also occur in the study of deformation properties of quasiconformal mappings. The authors study two important plane quasiconformal distortion functions, obtaining monotonicity and convexity properties, and finding sharp bounds for them. Applications are provided that relate to the quasiconformal Schwarz Lemma and to Schottky's Theorem. These results also yield new bounds for singular values of complete elliptic integrals.Comment: 23 page

Implementing an Architectural Framework to Define and Deliver Net-Centric Capability to Legacy Military Air Assets Operating within a System of Systems

The United States Air Force (USAF) is implementing an integrated net-centric system of systems for airborne operations in support of the global war on terror (GWOT). The GWOT demands that a successful architecture framework transforms and delivers net-centric assets to the war-fighter in a timely manner. A critical component of this implementation is the transformation of legacy strategic air platforms into net-centric air power assets operating within a system of systems. The System Architectural (SA) framework, and the Department of Defense Architectural Framework (DoDAF) are ways of managing complexity and organizing information within a system of systems network. This paper will explore and compare these architectural frameworks; show examples used in a system of systems network; and illustrate how the DoDAF can successfully define the transformation of a legacy weapon system into a net-centric asset