A Water Accounting System for Strategic Water Management

This paper describes a water accounting system (WAS) that has been developed as an innovative new tool for strategic long-term water management. The WAS incorporates both disaggregated water use and availability, provides a comprehensive and consistent historical database, and can integrate climate and hydrological model outputs for the exploration of scenarios. It has been established and tested for the state of Victoria in Australia, and can be extended to cover other or all regions of Australia. The WAS is implemented using stock-and-flow dynamics, currently employing major river basins as the spatial units and a yearly time step. While this system shares features with system dynamics, learning is enhanced and strategic management of water resources is improved by application of a Design Approach and the structure of the WAS. We compare the WAS with other relevant accounting systems and outline its benefits, particularly the potential for resolving tensions between water supply and demand. Integrated management is facilitated by combination with other stocks and flows frameworks that provide data on key drivers such as demography, land-use and electricity production.water accounts, stocks and flows, water budgets, decision support systems, strategic management

Knickpoints in Martian channels indicate past ocean levels

On Mars, the presence of extensive networks of sinuous valleys and large channels provides evidence for a wetter and warmer environment where liquid water was more abundant than it is at present. We undertook an analysis of all major channel systems on Mars and detected sharp changes in elevation along the river long profiles associated with steep headwall theatre-like valleys and terraces left downstream by channel incision. These breaks in channel longitudinal slope, headwalls and terraces exhibit a striking resemblance with terrestrial fluvial features, commonly termed 'knickpoints'. On Earth, such knickpoints can be formed by more resistant bedrock or where changes in channel base-level have initiated erosion that migrates upstream (such as tectonic uplift or sea level change). We observed common elevations of Martian knickpoints in eleven separate channel systems draining into the Martian Northern lowlands. Numerical modeling showed that the common elevations of some of these knickpoints were not random. As the knickpoints are spread across the planet, we suggest that these Martian knickpoints were formed in response to a common base level or ocean level rather than local lithology. Thus, they potentially represent a record of past ocean levels and channel activity on Mars

A microrod-resonator Brillouin laser with 240 Hz absolute linewidth

We demonstrate an ultralow-noise microrod-resonator based laser that oscillates on the gain supplied by the stimulated Brillouin scattering optical nonlinearity. Microresonator Brillouin lasers are known to offer an outstanding frequency noise floor, which is limited by fundamental thermal fluctuations. Here, we show experimental evidence that thermal effects also dominate the close-to-carrier frequency fluctuations. The 6-mm diameter microrod resonator used in our experiments has a large optical mode area of ~100 {\mu}m$^2$, and hence its 10 ms thermal time constant filters the close-to-carrier optical frequency noise. The result is an absolute laser linewidth of 240 Hz with a corresponding white-frequency noise floor of 0.1 Hz$^2$/Hz. We explain the steady-state performance of this laser by measurements of its operation state and of its mode detuning and lineshape. Our results highlight a mechanism for noise that is common to many microresonator devices due to the inherent coupling between intracavity power and mode frequency. We demonstrate the ability to reduce this noise through a feedback loop that stabilizes the intracavity power.Comment: 11 pages, 5 figure

The Role of Mannosyl-phosphoryl-dihydropolyisoprenol in the Synthesis of Mammalian Glycoproteins

A mouse myeloma tumor was used as a model system to study the biochemical steps involved in the incorporation of mannose into glycoproteins. This tumor, MOPC-46B, synthesizes a K-type immunoglobulin light chain (K-46) which is a glycoprotein with a single oligosaccharide side chain containing mannose as one of its constituent sugars. MOPC-46B microsomal preparations contain enzymes which transfer mannose from the sugar nucleotide, GDPmannose, to endogenous lipid and protein acceptors. Formation of the mannolipid proceeds by the reversible transfer of mannose from GDP-mannose to an endogenous phospholipid. The mannolipid was purified and characterized by chemical methods and mass spectrometry as a mannosyl-monophosphoryl- dihydropolyisoprenol, containing at least 18 isoprene units, one of which is saturated. The mannolipid was implicated as an intermediate in the in vitro mannosylation of endogenous protein acceptors by three kinds of experiments. (a) Incorporation of [l%]mannose into protein was observed after the initial substrate, GDP-mannose, had been destroyed by sugar nucleotide hydrolases associated with the microsomal preparations. The continued increase in radioactivity in the protein fraction occurred concomitantly with a loss of radioactivity from the mannolipid fraction. (b) I ncorporation of [14C]mannose into both lipid and protein was inhibited by EDTA added at zero time. However, addition of EDTA after mannolipid synthesis had occurred resulted in cessation of mannolipid formation but continued incorporation of mannose into protein to an extent proportional to the amount of mannolipid originally formed. The increase in radioactivity in protein was again accompanied by a loss of radioactivity from the mannolipid. (c) When microsomes were pulsed briefly with GDP-[14C]mannose, which was then chased by a large excess of unlabeled GDP-mannose, incorporation of [‘XZ]mannose into lipid ceased immediately with the chase, while incorporation into protein continued afterwards to an extent proportional to the amount of mannolipid formed prior to the chase. Evidence that the mannolipid could function as a donor of mannose residues to protein was obtained by demonstrating that microsomes catalyze the transfer of [*4C]mannose from exogenously supplied mannolipid to endogenous protein acceptors. The amount of mannose transferred to protein was proportional to both microsomal protein and lipid concentrations. In addition, the amount of mannose transferred to protein from exogenous mannolipid is comparable to that incorporated from an equivalent amount of mannolipid generated endogenously from GDP-mannose. Gel filtration profiles of the [14C]mannose-containing protein formed in this system are essentially identical regardless of whether GDP-mannose or mannolipid is used as substrate. In both cases the radioactive protein fractionates in a manner similar to authentic K-46 (mol wt 24,000). The mannose-containing protein formed from either GDPmannose or mannolipid was degraded sequentially by Pronase and subtilisin. The products formed from either substrate appeared to be identical and exhibited chromatographic and electrophoretic characteristics of glycopeptides. It was concluded that mammalian microsomal preparations contain an endogenous phospholipid, characterized as a dihydropolyisoprenol-monophosphate, which serves as an acceptor of mannose from GDP-mannose, resulting in the formation of mannosyl-monophosphoryl-dihydropolyisoprenol, and that this mannolipid serves as a glycosyl donor for transfer of mannose residues to endogenous protein acceptors. The evidence indicates that the mannolipid is an essential intermediate in the in vitro transfer of mannose from GDP-mannose to protein

Extreme Flood Sediment Production and Export Controlled by Reach‐Scale Morphology

Rapid earth surface evolution is discrete in nature, with short-duration extreme events having a widespread impact on landscapes despite occurring relatively infrequently. Here, we exploit a unique opportunity to identify the broad, process-based, controls on sediment production and export during extreme rainfall-runoff events through a multi-catchment analysis. A 3 hr extreme rainfall event generated significantly different impacts across three catchments, ranging from (a) sediment export exceeding two orders of magnitude more than the typical long term average to (b) a minimal impact, with this variability primarily controlled by catchment steepness and the presence of reach-scale morphological transitions caused by postglacial landscape adjustment. In any catchment worldwide where populations are at risk, we highlight the importance of combining topographic analysis with detailed mapping of channel bed material (e.g., presence of transitions between process domains) and identification of sediment sources within morphological transition zones for accurately predicting the impact of extreme events

Bringing Agroforestry Technology to Farmers in the Philippines: Identifying constraints to success using systems modelling

Bayesian Belief Network (BBN) modelling may be applied in rural extension in situations where program outputs are influenced by variables which are sequentially influenced by other variables. For a recently completed agroforestry extension program in Leyte the Philippines, BBN modelling of site factors, establishment practices and risk, predicted widely different program outputs for different levels of extension assistance and farmer inputs. In a situation where very little was known about how farmers would respond to offers of extension assistance, monitoring of the program over a period of three years revealed that extended extension assistance was crucial in determining the likely survival and growth of trees. Extended extension assistance was also important for the elimination of unsuitable sites and the use of appropriate establishment procedures. Where extension support was not available, farmers displayed a poor knowledge of the principles of tree growth, planting trees underneath complete canopies and adjacent to mature coconut palms even though they could have been expected to have extensive local knowledge of raising and growing plants. Approximately one third of planting sites were infertile and eroded and growth of newly planted trees on these sites was poor, often because site preparation and maintenance was minimal. Newly established trees were also found to be at risk from fire, typhoon, and grazing and in situations where plantations were destroyed, farmers became antagonistic towards the program. The implications of the BBN modelling for a hypothetically expanded program are that extended assistance and site inspections are necessary to eliminate planting trees on inappropriate and unsuitable sites and to improve establishment practices and weed control in order to avoid plantations of suppressed and chlorotic trees which fail to meet the expectations of farmers, thus impinging on the success of the program

BRINGING AGROFORESTRY TECHNOLOGY TO FARMERS IN THE PHILIPPINES: IDENTIFYING CONSTRAINTS TO THE SUCCESS OF EXTENSION ACTIVITIES USING SYSTEMS MODELLING

We present a systems modelling approach to evaluating the success of an agroforestry extension program in Leyte the Philippines. During the program, variables which are intrinsic to farmers’ socio-economic and farming systems were found to have influenced the uptake and acceptance of extension advice. Evaluation of the program therefore depended on identifying the variables and their interdependencies and assessing their relative influence on program outputs. For this purpose, a systems approach which encourages breaking systems into component variables, but also acknowledges the context of problems, assisted construction of models. Using both empirical data collected during program activities and input from stakeholders, Bayesian Belief Network (BBN) modelling was undertaken to predict critical success factors for the four main extension activities, namely recruitment, the effectiveness of written extension materials, development of farmers’ self-efficacy in nursery and silvicultural management and attrition of participating farmers. A key predicted constraint to program recruitment is farmers’ perception of harvest security and whereas this variable can be partly addressed through dissemination of information on harvesting legislation, title security cannot. Differing levels of farmers’ education flow through to differences in predicted reading ability, comprehension of extension literature and possible misconstrual of information. The variable most critical to the development of farmers’ self-efficacy is extended problem-solving support

Formation of o-Tyrosine and Dityrosine in Proteins during Radiolytic and Metal-catalyzed Oxidation

To evaluate their usefulness as chemical indicators of cumulative oxidative damage to proteins, we studied the kinetics and extent of formation of ortho-tyrosine (0-Tyr), dityrosine (DT), and dityrosine-like fluorescence (Ex = 3 17 nm, E,,, = 407 nm) in the model proteins RNase and lysozyme exposed to radiolytic and metalcatalyzed (H20z/Cu2+) oxidation (MCO). Although there were protein-dependent differences, o-Tyr, DT, and fluorescence increased coordinately during oxidation of the proteins in both oxidation systems. The contribution of DT to total dityrosine-like fluorescence in oxidized proteins varied from 2-10070, depending on the protein, type of oxidation, and extent of oxidative damage. In proteins exposed to MCO, DT typically accounted for \u3e50% of the fluorescence at DT wavelengths. These studies indicate that o-Tyr and DT should be useful chemical markers of cumulative exposure of proteins to MCO in vitro and in vivo

Oxidized Amino Acids in Lens Protein with Age: Measurement of o-Tyrosine and Dityrosine in the Aging Human Lens

The concentrations of ortho-tyrosine (o-Tyr) and dityrosine (DT) were measured in noncataractous human lenses in order to assess the role of proteinoxidation reactions in the aging of lens proteins. The measurements were conducted by selected ion monitoring-gas chromatography/mass spectrometry using deuterium-labeled internal standards, which provided both high sensitivity and specificity for the quantitation of o-Tyr and DT. Between ages 1 and 78 years, the o-Tyr concentration in lens proteins varied from 0.3 to 0.9 mmol of o-Tyr/mol of Phe (n = 19), while DT ranged from 1 to 3 mumol of DT/mol of Tyr (n = 30). There were no significant changes in levels of o-Tyr with lens age. There was a statistically significant, but only slight, increase in DT in lens proteins with age (approximately 33% increases between ages 1 and 78, r = 0.5, p \u3c 0.01). At the same time, totalprotein fluorescence, measured at DT wavelengths (Ex = 317 nm, Em = 407 nm), increased 11-fold between ages 1 and 78 and correlated strongly with age (r = 0.82, p \u3c 0.0001). Although the fluorescence maxima of lens proteins were similar to those of DT, DT accounted for less than 1% of the DT-like fluorescence in lens protein at all ages. These observations indicate that oxidation of Phe and Tyr plays a limited role in the normal aging of lens proteins in vivo