Assessing the Consequences of Brood Parasitism and Nest Predation On Seasonal Fecundity in Passerine Birds

Brood parasites and nest predators reduce the seasonal fecundity and, hence, the population growth rates of their victims. However, most field studies do not measure directly how parasites and predators decrease seasonal fecundity, but instead measure the impact of these organisms on individual nesting attempts. Because a female may renest after losing a nest to predation, abandoning a parasitized nest, or successfully fledging a brood, knowing how brood parasites and nest predators reduce the number of offspring fledged from individual nesting attempts is not equivalent to knowing their impact on seasonal fecundity. We address this problem by developing a mathematical model that: estimates several parameters describing the natural history of this system, including the brood-parasitism rate, nest-predation rate, and probability of nest abandonment in response to a parasitism event; and extrapolates to seasonal fecundity from these parameters and others describing the length of the breeding season, the timing of events in the nesting cycle, and the productivity of parasitized and unparasitized nests. We also show how different researchers using different observational methodologies to study exactly the same population likely would arrive at noticeably different conclusions regarding the intensity of brood parasitism, and we provide mathematical formulas for comparing among several of these measures of parasitism. Our procedures extend Mayfield's method for calculating nest-success rates from nest-history data in that we simultaneously estimate parameters describing nest predation and brood parasitism, predict seasonal fecundity from these parameters, and provide confidence intervals on all parameter estimates. The model should make the design and interpretation of logistically difficult empirical studies more efficient. It also can be specialized to species affected by nest predators but not brood parasites. We use the model to analyze prairie Warbler (Dendroica discolor) and Black-capped Vireo (Vireo atricapillus) nesting data. We estimate the model's parameters for these species and use the resulting estimates to predict seasonal fecundity. For both species, the predicted seasonal fecundity closely matches the value measured directly.Integrative Biolog

Temporal Variation In The Carrying Capacity Of A Perennial Grass Population

Density dependence and, therefore, K (carrying capacity, equilibrium population size) are central to understanding and predicting changes in population size (N). Although resource levels certainly fluctuate, K has almost always been treated as constant in both theoretical and empirical studies. We quantified temporal variation in K by fitting extensions of standard population dynamic models to 16 annual censuses of a population of the perennial bunch-grass Bouteloua rigidiseta. Variable-K models provided substantially better fits to the data than did models that varied the potential rate of population increase. The distribution of estimated values of K was skewed, with a long right tail (i.e., a few >jackpot> years). The population did not track K closely. Relatively slow responses to changes in K combined with large, rapid changes in K sometimes caused N to be far from K. In 13%-20% of annual intervals, K was so much larger than N that the population's dynamics were best described by geometric growth and the population was, in effect, unregulated. Explicitly incorporating temporal variation in K substantially improved the realism of models with little increase in model complexity and provided novel information about this population's dynamics. Similar methods would be applicable to many other data sets.Integrative Biolog

X-ray based extensometry

A totally new method of extensometry using an X-ray beam was proposed. The intent of the method is to provide a non-contacting technique that is immune to problems associated with density variations in gaseous environments that plague optical methods. X-rays are virtually unrefractable even by solids. The new method utilizes X-ray induced X-ray fluorescence or X-ray induced optical fluorescence of targets that have melting temperatures of over 3000 F. Many different variations of the basic approaches are possible. In the year completed, preliminary experiments were completed which strongly suggest that the method is feasible. The X-ray induced optical fluorescence method appears to be limited to temperatures below roughly 1600 F because of the overwhelming thermal optical radiation. The X-ray induced X-ray fluorescence scheme appears feasible up to very high temperatures. In this system there will be an unknown tradeoff between frequency response, cost, and accuracy. The exact tradeoff can only be estimated. It appears that for thermomechanical tests with cycle times on the order of minutes a very reasonable system may be feasible. The intended applications involve very high temperatures in both materials testing and monitoring component testing. Gas turbine engines, rocket engines, and hypersonic vehicles (NASP) all involve measurement needs that could partially be met by the proposed technology

Architectural assessment of mass storage systems at GSFC

The topics are presented in viewgraph form and include the following: system functionality; characteristics; data sources; hardware/software systems; and performance assessments

Evaluating Lupin\u27s Agricultural Potential as a Cover Crop in Vermont

Vermont\u27s intense seasonality and short, highly variable growing season can make it difficult for farmers to implement cover crops in crop rotations. Cover cropping is an important practice for improving soil quality, increasing the soil’s capacity to hold nutrients, and reducing run-off of fertilizers into rivers, streams, and lakes. Legumes with their nitrogen-fixing capacity and taproot structure are important as farmers look to reduce synthetic fertilizer inputs, soil compaction and increased environmental and fertilizer costs. The narrow leaf blue lupin (Lupinius augustifolius), evaluated in this field trial, is an annual variety grown extensively for green manure and cover cropping practices. It’s cold-hardiness, special taproot system, ability to mine phosphorus and fix nitrogen offer many potential uses in Vermont\u27s agriculture. It has potential for being a substitute for the less cold-tolerant soybean in maize systems and as a new source of highly digestible protein feed for dairy and livestock systems. Field trials were conducted to evaluate the potential of lupins as a cover crop here in Vermont by measuring yields and effect on nutrient status and soil properties across five varieties of narrowleaf lupin. Narrowleaf blue lupins were found to be viable cover crops. The lupin variety Roland showed the most promising performance by increasing macronutrient and micronutrient profile, having the earliest flowering time, and performing strongly for other important agronomic traits

Effective speed of sound in phononic crystals

A new formula for the effective quasistatic speed of sound $c$ in 2D and 3D periodic materials is reported. The approach uses a monodromy-matrix operator to enable direct integration in one of the coordinates and exponentially fast convergence in others. As a result, the solution for $c$ has a more closed form than previous formulas. It significantly improves the efficiency and accuracy of evaluating $c$ for high-contrast composites as demonstrated by a 2D example with extreme behavior.Comment: 4 pages, 1 figur

Reaching Approximate Byzantine Consensus with Multi-hop Communication

We address the problem of reaching consensus in the presence of Byzantine faults. In particular, we are interested in investigating the impact of messages relay on the network connectivity for a correct iterative approximate Byzantine consensus algorithm to exist. The network is modeled by a simple directed graph. We assume a node can send messages to another node that is up to $l$ hops away via forwarding by the intermediate nodes on the routes, where $l\in \mathbb{N}$ is a natural number. We characterize the necessary and sufficient topological conditions on the network structure. The tight conditions we found are consistent with the tight conditions identified for $l=1$, where only local communication is allowed, and are strictly weaker for $l>1$. Let $l^*$ denote the length of a longest path in the given network. For $l\ge l^*$ and undirected graphs, our conditions hold if and only if $n\ge 3f+1$ and the node-connectivity of the given graph is at least $2f+1$ , where $n$ is the total number of nodes and $f$ is the maximal number of Byzantine nodes; and for $l\ge l^*$ and directed graphs, our conditions is equivalent to the tight condition found for exact Byzantine consensus. Our sufficiency is shown by constructing a correct algorithm, wherein the trim function is constructed based on investigating a newly introduced minimal messages cover property. The trim function proposed also works over multi-graphs.Comment: 24 pages, 1 figure. arXiv admin note: text overlap with arXiv:1203.188

Altmetrics for the Information Professional: A Primer

Altmetrics, or alternative citation metrics, provide researchers and scholars with new ways to track influence across a wide range of media and platforms. From deciding what to read based on tweets, to enhancing scholarship with collaboration, altmetrics will exert more and more influence on the scholarly landscape. Awareness of altmetric tools, and the ways in which they can be used, will position information professionals at the forefront of this exciting new era in knowledge dissemination and assessment. As social media plays an ever increasing role in the communication of scholarship, the authors will discuss how altmetrics can be a valuable addition to the information professional’s tool kit. Beginning with a review of simple readership tools, and continuing with an overview of complex aggregator programs, the most promising and/or mature products will be described. Some of the many uses of altmetric data will be discussed, including the advantages of participating in large, diverse interest groups, informal reviews of formal documents, and the rapid (and arguably more complete) measure of research impact. The authors will further demonstrate how to use altmetrics to complement and enhance existing methods to provide readership advisory services for ourselves and our patrons, facilitate knowledge sharing, indicate effectiveness, and supply evidence for promotion and tenure