Nutrient Management Approaches and Tools for Dairy Farms in Australia and the U.S.

Nutrient surpluses in industrialized nations like the U.S. and Australia are causing problems on dairy farms and posing a threat to the rest of the environment. This paper discusses tools that dairy farmers can use to manage the excess nutrients while continuing to meet demands and profit. The authors suggest improvements in these tools that will not only quantify the amount of nutrient balances on dairy farms, but also identify opportunities for enhanced nutrient use and reduced nutrient losses.Nutrient Management Tools, Australian Dairy Farms, U.S. Dairy Farms, Confinement-based Dairy Operations, Grazing-based Diary Operations, Environmental Economics and Policy, Farm Management, Land Economics/Use,

A 100-year record of North Pacific volcanism in an ice core from Eclipse icefield, Yukon Territory, Canada

A record of regionally significant volcanic eruptions in the North Pacific over the last century has been developed using a glaciochemical record from Eclipse Icefield, Yukon Territory, Canada. Tephrochronology of the Eclipse ice core provides positive identification of the 1907 Ksudach, Kamchatka, the 1912 Katmai, Alaska, the 1947 Hekla, Iceland, and the 1989 Redoubt, Alaska, eruptions. Non-sea-salt SO42− residuals above a robust spline and empirical orthogonal function (EOF) analysis were used to identify volcanic SO42− signatures. Volcanic sulfate values are more conservatively identified by the EOF analysis as sulfate deposition from other sources is more robustly accounted for. Some eruptions are also recorded as peaks in non-sea-salt chloride. The volcanic signals in the Eclipse ice core are mostly attributable to Alaskan, Aleutian, or Kamchatkan eruptions. Conversely, the Eclipse ice core provides a poor record of globally significant tropical eruptions. These results are promising for the development of longer ice core based records of paleovolcanism in the North Pacific rim

A Problem Model for Decision Support Systems

This body of research focuses on supporting problem-stakeholders, decision-makers and problem-solvers faced with an ill-defined and complex real world problem. An ill-defined problem has a characteristic trait of continual refinement. The central theme of this research is that a support system should provide problem stakeholders with a problem definition model for constructing and manipulating a representation of the definition of the problem as they understand it. The approach adopted herein is to first develop a problem definition model for ill-defined problems— the 6-Component problem definition model. With this model, it is then possible to move on to identifying the types of changes or modifications to the problem definition that problem stakeholders, decision makers and problem solvers may wish to explore. Importantly, there must be a connection between the surface representation of the problem and the underlying implementation of the support system. This research argues that by focusing the support system around the problem definition, it is possible to reduce the mismatch between the problem objectives and the representation of the problem that the support system offers. This research uses the Unified Modelling Language to record and explore the requirements that problem stakeholders, faced with an evolving problem definition, place on a support system. The 6-Component problem definition model is then embedded within a design for an evolutionary support system. This embedding, supported by collaboration diagrams, shows how a system using the 6-Component problem definition model will support stakeholders in their exploration, evaluation and resolution of an ill-defined and complex real-world problem. A case study provides validation of the effectiveness of the 6-Component problem definition model proposed and developed in this work. The case study uses the 6-Component problem definition model as a basis for implementing the Integration Workbench, an evolutionary support system for land-use planning. Stakeholders explore, communicate, evaluate and resolve the Tasmanian Regional Forest Agreement problem with assistance from the Integration Workbench

Multi-scale Population and Mobility Estimation with Geo-tagged Tweets

Recent outbreaks of Ebola and Dengue viruses have again elevated the significance of the capability to quickly predict disease spread in an emergent situation. However, existing approaches usually rely heavily on the time-consuming census processes, or the privacy-sensitive call logs, leading to their unresponsive nature when facing the abruptly changing dynamics in the event of an outbreak. In this paper we study the feasibility of using large-scale Twitter data as a proxy of human mobility to model and predict disease spread. We report that for Australia, Twitter users' distribution correlates well the census-based population distribution, and that the Twitter users' travel patterns appear to loosely follow the gravity law at multiple scales of geographic distances, i.e. national level, state level and metropolitan level. The radiation model is also evaluated on this dataset though it has shown inferior fitness as a result of Australia's sparse population and large landmass. The outcomes of the study form the cornerstones for future work towards a model-based, responsive prediction method from Twitter data for disease spread.Comment: 1st International Workshop on Big Data Analytics for Biosecurity (BioBAD2015), 4 page

Object replication in a distributed system

PhD ThesisA number of techniques have been proposed for the construction of fault—tolerant applications. One of these techniques is to replicate vital system resources so that if one copy fails sufficient copies may still remain operational to allow the application to continue to function. Interactions with replicated resources are inherently more complex than non—replicated interactions, and hence some form of replication transparency is necessary. This may be achieved by employing replica consistency protocols to mask replica failures and maintain consistency of state between functioning replicas. To achieve consistency between replicas it is necessary to ensure that all replicas receive the same set of messages in the same order, despite failures at the senders and receivers. This can be accomplished by making use of order preserving reliable communication protocols. However, we shall show how it can be more efficient to use unordered reliable communication and to impose ordering at the application level, by making use of syntactic knowledge of the application. This thesis develops techniques for replicating objects: in general this is harder than replicating data, as objects (which can contain data) can contain calls on other objects. Handling replicated objects is essentially the same as handling replicated computations, and presents more problems than simply replicating data. We shall use the concept of the object to provide transparent replication to users: a user will interact with only a single object interface which hides the fact that the object is actually replicated. The main aspects of the replication scheme presented in this thesis have been fully implemented and tested. This includes the design and implementation of a replicated object invocation protocol and the algorithms which ensure that (replicated) atomic actions can manipulate replicated objects.Research Studentship, Science and Engineering Research Council. Esprit Project 2267 (Integrated Systems Architecture)

A general study of Minoan frescoes with particular reference to unpublished wall painting from Knossos

PhD ThesisThis four-part dissertation considers Minoan frescoes in their own right for a first time, with reference to unpublished paintings and nearly fifty new restorations, with a view to providing a new basis for historical reconstruction drawn from that source. Earliest developments begin with Neolithic architectural muse of mud plasters, the first painted plasters occuring in EM II settlements and simple decorative schemes in the First Palaces (1900-1700 B.C.). The sudden rise of pictorial naturalism in MM IIIA is explained by native cultural developments of the First Palace Period, not by foreign influences or "eideticism" which is rejected altogether. A review of the motival repertory leads to considerations of six main "cycles of ideas" whence the painters derived their themes. The most important, confined to Knossos palace, depicts a major festival of grand processions and athletic activities before the chief Minoan goddess, and it illuminates the palatial architechural design. But five different systems of mural decoration characterise Minoan architecture as a whole, with regional and perhaps autonomous variations at Cycadic sites. Technical considerations confirm "buon fresco" as the normal painting technique and distinguish Knossian town house and palace murals in construction and purpose. Similar distinctions in compositional design are also described. A review of eleven "schools" of Knossian painters and of regional artists precedes a detailed reconstruction of the dates of the frescoes on stratigraphical, stylistic and comparative evidence. Sir Arthur Evans's fresco dating should generally be lowered by one Minoan phase. Minoan pictorial painting ceases with the palace destruction at Knossos, c.1375 B.C. Major differences appear between pre- and post-LM IB frescoes, tentatively explained on the evidence of Aegean and Egyption pictorial representations by the arrival at Knossos of a Mycenaean military dynasty, c.1450 B.C. Minoan wall painting finally disappeared in the LM IIIB period

Ice core paleovolcanic records from the St. Elias Mountains, Yukon, Canada

We previously reported a record of regionally significant volcanic eruptions in the North Pacific using an ice core from Eclipse Icefield (St. Elias Mountains, Yukon, Canada). The acquisition of two new ice cores from Eclipse Icefield, along with the previously available Eclipse Icefield and Mount Logan Northwest Col ice cores, allows us to extend our record of North Pacific volcanism to 550 years before present using a suite of four ice cores spanning an elevation range of 3–5 km. Comparison of volcanic sulfate flux records demonstrates that the results are highly reproducible, especially for the largest eruptions such as Katmai (A.D. 1912). Correlation of volcanic sulfate signals with historically documented eruptions indicates that at least one-third of the eruptions recorded in St. Elias ice cores are from Alaskan and Kamchatkan volcanoes. Although there are several moderately large (volcanic explosivity index (VEI) ≥ 4) eruptions recorded in only one core from Eclipse Icefield, the use of multiple cores provides signals in at least one core from all known VEI ≥ 4 eruptions in Alaska and Kamchatka since A.D. 1829. Tephrochronological evidence from the Eclipse ice cores documents eruptions in Alaska (Westdahl, Redoubt, Trident, and Katmai), Kamchatka (Avachinsky, Kliuchevoskoi, and Ksudach), and Iceland (Hekla). Several unidentified tephra-bearing horizons, with available geochemical evidence suggesting Alaskan and Kamchatkan sources, were also found. We present a reconstruction of annual volcanic sulfate loading for the North Pacific troposphere based on our ice core data, and we provide a detailed assessment of the atmospheric and climatic effects of the Katmai eruption

Ice core evidence for a second volcanic eruption around 1809 in the Northern Hemisphere

A volcanic signal observed in ice cores from both polar regions six years prior to Tambora is attributed to an unknown tropical eruption in 1809. Recovery of dacitic tephra from the 1809 horizon in a Yukon ice core (Eclipse) that is chemically distinct from andesitic 1809 tephra found in Antarctic ice cores indicates a second eruption in the Northern Hemisphere at this time. Together with the similar magnitude and timing of the 1809 volcanic signal in the Arctic and Antarctic, this could suggest a large tropical eruption produced the sulfate and Antarctic tephra and a minor Northern Hemisphere eruption produced the Eclipse tephra. Nonetheless, the possibility that there were coincidental eruptions of similar magnitude in both hemispheres, rather than a single tropical eruption, should not be discounted. Correctly attributing the source of the 1809 volcanic signal has important implications for modeling the magnitude and latitudinal distribution of volcanic radiative forcing