The direct measurement of ATP and adenine nucleotide pool turnover in microorganisms: a new method for environmental assessment of metabolism, energy flux and phosphorus dynamics

A method has been devised which enables the direct measurement of ATP and adenine nucleotide pool turnover. The method is based upon the incorporation of 32PO4 into the α-, β-, γ-P positions of ATP. 32PO4 uptake time course experiments were conducted in seawater and freshwater samples. Determinations of the ATP concentration and of the specific activities of the α-, β-, and γ-positioned 32P in ATP at sequential time points enables the calculation of: (1) the pool size of total biologically available P in water samples; (2) the rate of biochemical energy flux; and (3) the mean microbial community specific growth rate. This method is relatively simple, straightforward and extremely sensitive. It has, therefore, the advantage that it can be employed in environments where dissolved P levels are too low to obtain reliable P flux estimates using existing technique

Probing the qudit depolarizing channel

For the quantum depolarizing channel with any finite dimension, we compare three schemes for channel identification: unentangled probes, probes maximally entangled with an external ancilla, and maximally entangled probe pairs. This comparison includes cases where the ancilla is itself depolarizing and where the probe is circulated back through the channel before measurement. Compared on the basis of (quantum Fisher) information gained per channel use, we find broadly that entanglement with an ancilla dominates the other two schemes, but only if entanglement is cheap relative to the cost per channel use and only if the external ancilla is well shielded from depolarization. We arrive at these results by a relatively simple analytical means. A separate, more complicated analysis for partially entangled probes shows for the qudit depolarizing channel that any amount of probe entanglement is advantageous and that the greatest advantage comes with maximal entanglement

Final Report: Lake Vostok: A Curiosity or a Focus for Interdisciplinary Study?

The goal of the NSF-sponsored workshop, held in held in Washington, D.C., on November 7-8, 1998, was to stimulate discussion within the U.S. science community on Lake Vostok, specifically addressing the question: "Is Lake Vostok a natural curiosity or an opportunity for uniquely posed interdisciplinary scientific programs?" The workshop was designed to outline an interdisciplinary science plan for studies of the lake

Evolutionary Processes a Focus of Decade-Long Ecosystem Study of Antarctic's Lake Vostok

As scientists probe for life in new habitats and try to understand the processes that triggered the origin and guided the evolution of life on Earth, environments beneath large ice sheets are beginning to emerge as key ecosystems. Modern subglacial environments are analogues both for the icy moons of Jupiter and the environmental stresses that led to widespread evolutionary radiation following the Neoproterozoic "snowball" Earth. The largest modern analogue to these distant systems is Lake Vostok, a great Antarctic subglacial lake, and the international science community is developing a plan to systematically survey and explore this complex system over the next decade. Approximately the size of Lake Ontario, Lake Vostok lies beneath the 4 km thick East Antarctic ice sheet (Figure 1). The lake is much deeper than Lake Ontario—remotely measured water depths reach 670 m

A Hierarchal Planning Framework for AUV Mission Management in a Spatio-Temporal Varying Ocean

The purpose of this paper is to provide a hierarchical dynamic mission planning framework for a single autonomous underwater vehicle (AUV) to accomplish task-assign process in a limited time interval while operating in an uncertain undersea environment, where spatio-temporal variability of the operating field is taken into account. To this end, a high level reactive mission planner and a low level motion planning system are constructed. The high level system is responsible for task priority assignment and guiding the vehicle toward a target of interest considering on-time termination of the mission. The lower layer is in charge of generating optimal trajectories based on sequence of tasks and dynamicity of operating terrain. The mission planner is able to reactively re-arrange the tasks based on mission/terrain updates while the low level planner is capable of coping unexpected changes of the terrain by correcting the old path and re-generating a new trajectory. As a result, the vehicle is able to undertake the maximum number of tasks with certain degree of maneuverability having situational awareness of the operating field. The computational engine of the mentioned framework is based on the biogeography based optimization (BBO) algorithm that is capable of providing efficient solutions. To evaluate the performance of the proposed framework, firstly, a realistic model of undersea environment is provided based on realistic map data, and then several scenarios, treated as real experiments, are designed through the simulation study. Additionally, to show the robustness and reliability of the framework, Monte-Carlo simulation is carried out and statistical analysis is performed. The results of simulations indicate the significant potential of the two-level hierarchical mission planning system in mission success and its applicability for real-time implementation

Detection of vibrational emissions from the helium hydride ion (HeH+^+) in the planetary nebula NGC 7027

We report the detection of emission in the v=1-0 P(1) (3.51629 micron) and P(2) (3.60776 micron) rovibrational lines of the helium hydride cation (HeH+) from the planetary nebula NGC 7027. These detections were obtained with the iSHELL spectrograph on NASA's Infrared Telescope Facility (IRTF) on Maunakea. The confirm the discovery of HeH+ reported recently by Guesten et al. (2019), who used the GREAT instrument on the SOFIA airborne observatory to observe its pure rotational J=1-0 transition at 149.137 micron. The flux measured for the HeH+ v=1-0 P(1) line is in good agreement with our model for the formation, destruction and excitation of HeH+ in NGC 7027. The measured strength of the J=1-0 pure rotational line, however, exceeds the model prediction significantly, as does that of the v=1-0 P(2) line, by factors of 2.9 and 2.3 respectively. Possible causes of these discrepancies are discussed. Our observations of NGC 7027, covering the 3.26 - 3.93 micron spectral region, have led to the detection of more than sixty spectral lines including nine rovibrational emissions from CH+. The latter are detected for the first time in an astronomical source.Comment: 49 pages, including 17 figures. Accepted for publication in Ap

Hindered Rotation in Molecules with Relatively High Potential Barriers

The theory of hindered rotation has been applied to the type of asymmetric molecule in which the hindering barrier is high enough so that the hindered rotation splittings of the energy levels are small compared with the rotational energies but yet large enough to be observable in the microwave spectrum. The specific type of molecule considered consists of a rigid asymmetric component which may undergo a hindered rotation about the symmetry axis of a rigid symmetric component where the symmetric component is in addition assumed to have threefold symmetry and the asymmetric component at least a plane of symmetry containing the symmetry axis of the symmetric component. An example might be the acetaldehyde molecule, CH3CHO.In principle, the theory developed by Burkhard and Dennison can be used directly but in practice the method is difficult to apply to such a molecule since the matrix elements of the Hamiltonian used previously do not degenerate naturally or easily to those for the rigid asymmetric rotator in the infinite barrier limit. In the present treatment a transformation is made on the Hamiltonian whereby this complication is avoided and the resulting calculations are greatly simplified.It is found that the spectrum is essentially that of the rigid rotator with the important exception that all the strong lines are split into two components. For the low J transitions specific formulas have been derived for these splittings which are relatively simple functions of the barrier height, the principal moments of inertia, and two additional parameters involving the molecular dimensions and the masses. The barrier height can thus be deduced from the observed splittings without the use of the somewhat cumbersome machinery needed in the general case.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69966/2/JCPSA6-26-1-31-1.pd

New Zealand Guidelines for cyanobacteria in recreational fresh waters: Interim Guidelines

This document is divided into four main sections, plus 14 appendices. Section 1. Introduction provides an overview of the purpose and status of the document as well as advice on who should use it. Section 2. Framework provides a background to the overall guidelines approach, recommendations on agency roles and responsibilities, and information on the condition of use of this document. Section 3. Guidelines describes the recommended three-tier monitoring and action sequence for planktonic and benthic cyanobacteria. Section 4. Sampling provides advice on sampling planktonic and benthic cyanobacteria. The appendices give further background information and include templates for data collection and reporting, including: • background information on known cyanotoxins and their distribution in New Zealand • information on the derivation of guideline values • photographs of typical bloom events • a list of biovolumes for common New Zealand cyanobacteria • templates for field assessments • suggested media releases and warning sign templates. A glossary provides definitions for abbreviations and terms used in these guidelines