Effects of seasonal variation in prey abundance on field metabolism, water flux, and activity of a tropical ambush foraging snake

The responses of animals to seasonal food shortages can have important consequences for population dynamics and the structure and function of food webs. We investigated how an ambush foraging snake, the northern death adder Acanthophis praelongus, responds to seasonal fluctuations in prey availability in its tropical environment. In the dry season, field metabolic rates and water flux, as measured by doubly labeled water, were significantly lower than in the wet season. Unlike some other reptiles of the wet-dry tropics, death adders showed no seasonal difference in their resting metabolism. About 94% of the decrease in energy expended in the dry season was due to a decrease in activity and digestion, with lower body temperatures accounting for the remainder. In the dry season, death adders were less active and moved shorter distances between foraging sites than in the wet season. Analysis of energy expenditure suggested that adders fed no more than every 2-3 wk in the dry season but fed more frequently during the wet season. Unlike many lizards that cease feeding during the dry season, death adders remain active and attempt to maximize their energy intake year-round

Epidemiological factors impacting the development of Wheat streak mosaic virus outbreaks

Master of ScienceDepartment of Plant PathologyErick D. DeWolfWheat streak mosaic (WSM) is a devastating disease of winter wheat (Triticum aestivum L.) in Kansas. Although WSM can cause heavy crop losses, the severity of regional and statewide losses varies by year and location. Wheat streak mosaic is caused primarily by the Wheat streak mosaic virus (WSMV) and is spread by the wheat curl mite, Aceria tosichella Keifer. To infect fall planted wheat, both the virus and mite require a living, grass host to survive the summer months. The first research objective was to determine the risk of different grass species to serve as a source of WSM. Published experiments and surveys were reviewed to determine the suitability of each host based on a set of criteria. An analysis of the reports from the reviewed literature found 39 species to host both pests. Categorical analysis of these observations suggested that well-studied grass species could be placed in four risk groupings with ten species at high risk of carrying both pests. Furthermore, results from controlled experimentation generally agrees with results from field survey results for both pests. The second objective was to determine the weather and cropping factors that are associated with regional epidemics of WSM in Kansas. Historic disease observations, weather summaries, soil moisture indices, and cropping statistics were collected from Kansas crop reporting districts from 1995-2013. Binary response variables (non-epidemic case vs epidemic cases) were developed from different thresholds of district losses attributed to WSM. Variables associated with WSM epidemics were identified by a combination of non-parametric correlation, classification trees, and logistic regression. This analysis indicates that the total acres of wheat planted per season was associated with the low frequency of epidemics in Eastern Kansas. Temperature during September appears to influence the yield losses caused by WSM. Wheat planting generally begins during September and continues through October in the state. Temperature during the winter months (December-February) was also identified as important with warm conditions favoring outbreaks of disease. Dry soil conditions in February was also associated with epidemics of WSM. Models combining these variables correctly classified 60 to 74% of the cases considered in this analysis

The Good, the Bad, and the Ugly: Agonistic Behaviour in Juvenile Crocodilians

We examined agonistic behaviour in seven species of hatchling and juvenile crocodilians held in small groups (N = 4) under similar laboratory conditions. Agonistic interactions occurred in all seven species, typically involved two individuals, were short in duration (5–15 seconds), and occurred between 1600–2200 h in open water. The nature and extent of agonistic interactions, the behaviours displayed, and the level of conspecific tolerance varied among species. Discrete postures, non-contact and contact movements are described. Three of these were species-specific: push downs by C. johnstoni; inflated tail sweeping by C. novaeguineae; and, side head striking combined with tail wagging by C. porosus. The two long-snouted species (C. johnstoni and G. gangeticus) avoided contact involving the head and often raised the head up out of the way during agonistic interactions. Several behaviours not associated with aggression are also described, including snout rubbing, raising the head up high while at rest, and the use of vocalizations. The two most aggressive species (C. porosus, C. novaeguineae) appeared to form dominance hierarchies, whereas the less aggressive species did not. Interspecific differences in agonistic behaviour may reflect evolutionary divergence associated with morphology, ecology, general life history and responses to interspecific conflict in areas where multiple species have co-existed. Understanding species-specific traits in agonistic behaviour and social tolerance has implications for the controlled raising of different species of hatchlings for conservation, management or production purposes

Dialogue based interfaces for universal access.

Conversation provides an excellent means of communication for almost all people. Consequently, a conversational interface is an excellent mechanism for allowing people to interact with systems. Conversational systems are an active research area, but a wide range of systems can be developed with current technology. More sophisticated interfaces can take considerable effort, but simple interfaces can be developed quite rapidly. This paper gives an introduction to the current state of the art of conversational systems and interfaces. It describes a methodology for developing conversational interfaces and gives an example of an interface for a state benefits web site. The paper discusses how this interface could improve access for a wide range of people, and how further development of this interface would allow a larger range of people to use the system and give them more functionality

Hybrid corrosion protection of a prestressed concrete bridge

The Kyle of Tongue Bridge in Sutherland, Northern Scotland opened in 1970, has an overall span of 184m of 18 approximately equal spans and carries a single lane dual carriageway. The bridge was repaired in 1989 due to chloride induced corrosion. However, inspections from 1999 onwards reported on-going corrosion and structural deterioration. A refurbishment contract was let in 2011 to extend the service life of the structure for a 20 year period by providing corrosion arrest and prevention. This paper describes how hybrid corrosion protection was used to offer protection to the prestressed concrete beams of the bridge. The results indicate that hybrid anodes provide an attractive alternative to other corrosion protection systems as they can be targeted to specific areas of need. They offer a temporary energising phase to arrest corrosion, followed by a permanent galvanic mode phase which is particularly beneficial for prestressed concrete structures in order to reduce the risk of hydrogen embrittlement

Exact asymptotics of the freezing transition of a logarithmically correlated random energy model

We consider a logarithmically correlated random energy model, namely a model for directed polymers on a Cayley tree, which was introduced by Derrida and Spohn. We prove asymptotic properties of a generating function of the partition function of the model by studying a discrete time analogy of the KPP-equation - thus translating Bramson's work on the KPP-equation into a discrete time case. We also discuss connections to extreme value statistics of a branching random walk and a rescaled multiplicative cascade measure beyond the critical point

Modeling brine inflow to Room Q: A numerical investigation of flow mechanisms

A hydrologic modeling study was performed to gain insight into the flow mechanisms around Room Q. A summary of hydrologic and structural data and of predictive fluid flow models from Room Q are provided. Six years of measured data are available from the time of excavation. No brine accumulation in Room Q was measured in the first two years following excavation. However, there is considerable uncertainty associated with this early-time data due to inadequate sealing of the room. Brine may have been lost to evaporation or it may have flowed into newly created disturbed rock zone (DRZ) porosity resulting from excavation. Non-zero brine accumulation rates were measured from 2--5 years, but brine accumulation within the room dropped to zero after 5.5 years. A conceptual model for brine inflow to Room Q was developed which assumes far-field Darcy flow combined with an increasing DRZ pore volume. Numerical simulations employed TOUGH28W and used predictive DRZ porosity increase with time from SPECTROM-32 rock deformation simulations. Simulated brine inflow showed good agreement with measured brine accumulation rates for the first five years. Two important conclusions were drawn from the simulation results: (1) early-time brine inflow to the room can be reduced to zero if the DRZ pore volume increases with time, and (2) brine accumulation (inflow) rates from 2 to 5 years suggest a far-field permeability of 5 {times} 10{sup {minus}22} m{sup 2} with a bulk rock compressibility of 5.4 {times} 10{sup {minus}12} Pa{sup {minus}1}

Chaotic scalar fields as models for dark energy

We consider stochastically quantized self-interacting scalar fields as suitable models to generate dark energy in the universe. Second quantization effects lead to new and unexpected phenomena is the self interaction strength is strong. The stochastically quantized dynamics can degenerate to a chaotic dynamics conjugated to a Bernoulli shift in fictitious time, and the right amount of vacuum energy density can be generated without fine tuning. It is numerically observed that the scalar field dynamics distinguishes fundamental parameters such as the electroweak and strong coupling constants as corresponding to local minima in the dark energy landscape. Chaotic fields can offer possible solutions to the cosmological coincidence problem, as well as to the problem of uniqueness of vacua.Comment: 30 pages, 3 figures. Replaced by final version accepted by Phys. Rev.

Probing the extragalactic fast transient sky at minute timescales with DECam

Searches for optical transients are usually performed with a cadence of days to weeks, optimised for supernova discovery. The optical fast transient sky is still largely unexplored, with only a few surveys to date having placed meaningful constraints on the detection of extragalactic transients evolving at sub-hour timescales. Here, we present the results of deep searches for dim, minute-timescale extragalactic fast transients using the Dark Energy Camera, a core facility of our all-wavelength and all-messenger Deeper, Wider, Faster programme. We used continuous 20s exposures to systematically probe timescales down to 1.17 minutes at magnitude limits $g > 23$ (AB), detecting hundreds of transient and variable sources. Nine candidates passed our strict criteria on duration and non-stellarity, all of which could be classified as flare stars based on deep multi-band imaging. Searches for fast radio burst and gamma-ray counterparts during simultaneous multi-facility observations yielded no counterparts to the optical transients. Also, no long-term variability was detected with pre-imaging and follow-up observations using the SkyMapper optical telescope. We place upper limits for minute-timescale fast optical transient rates for a range of depths and timescales. Finally, we demonstrate that optical $g$-band light curve behaviour alone cannot discriminate between confirmed extragalactic fast transients such as prompt GRB flashes and Galactic stellar flares.Comment: Published in MNRA

Summary of applications of TOUGH2 to the evaluation of multiphase flow processes at the WIPP

The Waste Isolation Pilot Plant (WIPP) is a US Department of Energy (DOE) research and development facility for the underground disposal of transuranic waste in southeastern New Mexico. The WIPP repository is located 655 m below the land surface in the lower portion of the Salado Formation, which is comprised of beds of pure and impure halite with thin interbeds of anhydrite and related clay seams. The regional dip of the Salado Formation is approximately 1{degree} southeast in the vicinity of the repository. The proposed waste storage area has eight waste disposal panels, each of which will contain seven rooms. The repository is designed to follow a single stratigraphic horizon. Due to the dip, the north end of the repository will be about 10 meters higher than the south end. Waste that is emplaced in the disposal rooms will generate gas due to microbial degradation, anoxic corrosion, and radiolysis. Brine inflow to the rooms from the surrounding Salado Formation may significantly influence the gas generation rate and the total amount of gas generated. The salt surrounding the repository will creep in response to the excavation, reducing the room volume. Gas generation in the room may increase the pressure sufficiently to drive brine and gas into the surrounding Salado Formation. Migration of gas and brine in the Salado is an important factor in evaluating the performance of the repository. The studies summarized in this paper have. been performed to evaluate brine and gas flow processes in the WIPP disposal system and to identify some of the important processes. These studies are done in support of, but are not part of, the formal Performance Assessment (PA) effort. Because of probabilistic and system-scale requirements, the PA effort uses the Sandia-developed BRAGFLO (BRine And Gas FLOw) code for multiphase flow calculations