Breeding Ecology and Productivity of Red-Necked Grebes in Turtle Mountain Provincial Park, Manitoba

The breeding biology and productivity of the Red-necked Grebe (Podiceps grisegena) were studied in Turtle Mountain Provincial Park, Manitoba, during 1980 and 1981. Arrival dates ranged from mid-April to early June. Pre-nesting intervals ranged from 11 o 42 days and averaged about 20 days. Egg-laying commenced in early May and extended until mid-July. The average clutch size (4.95 eggs) was much larger than those found in other studies of the Red-necked Grebe in North America. Although the nest success rate was low (26.2%), most failed pairs (83.5%) initiated at least 1 replacement clutch, and more than one-half of the observed pairs successfully hatched 1 or more chicks. Predators, primarily the Raccoon (Procyon lotor), were believed responsible for about half of the egg losses. High residue levels of several pesticides, particularly DDE and PCBs, were believed to have contributed to the low nesting success. About one-quarter of the viability-tested eggs during this study were considered inviable. Ratcliffe indices revealed that thin-shelled eggs were produced and several cracked eggs were found. Average incubation periods calculated during this study (28-29 days) were longer than the 22-23 day incubation period generally recognized in the literature. Hatching occurred throughout June and July. Successful pairs hatched an average of 2.5 young, but raised only 1.9 young to the age of 1 month. High pesticide loads may have contributed to many of the losses that occurred during pre- and post-hatching stages. Later, intraspecific aggression probably contributed to significant differences in individual mortality rates within large and small broods. Because losses during the second month were minimal, Red-necked Grebes during this study fledged 1.8-1.9 young/successful pair or about 0.9 young/breeding pair

EP-1811: Accuracy of dose calculations on CBCT scans of lung cancer patients using a vendor-specific approach

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Classification of Higher Dimensional Spacetimes

We algebraically classify some higher dimensional spacetimes, including a number of vacuum solutions of the Einstein field equations which can represent higher dimensional black holes. We discuss some consequences of this work.Comment: 16 pages, 1 Tabl

Inference of the genetic network regulating lateral root initiation in Arabidopsis thaliana

Regulation of gene expression is crucial for organism growth, and it is one of the challenges in Systems Biology to reconstruct the underlying regulatory biological networks from transcriptomic data. The formation of lateral roots in Arabidopsis thaliana is stimulated by a cascade of regulators of which only the interactions of its initial elements have been identified. Using simulated gene expression data with known network topology, we compare the performance of inference algorithms, based on different approaches, for which ready-to-use software is available. We show that their performance improves with the network size and the inclusion of mutants. We then analyse two sets of genes, whose activity is likely to be relevant to lateral root initiation in Arabidopsis, by integrating sequence analysis with the intersection of the results of the best performing methods on time series and mutants to infer their regulatory network. The methods applied capture known interactions between genes that are candidate regulators at early stages of development. The network inferred from genes significantly expressed during lateral root formation exhibits distinct scale-free, small world and hierarchical properties and the nodes with a high out-degree may warrant further investigation

A perturbative analysis of tachyon condensation

Tachyon condensation in the open bosonic string is analyzed using a perturbative expansion of the tachyon potential around the unstable D25-brane vacuum. Using the leading terms in the tachyon potential, Pad\'e approximants can apparently give the energy of the stable vacuum to arbitrarily good accuracy. Level-truncation approximations up to level 10 for the coefficients in the tachyon potential are extrapolated to higher levels and used to find approximants for the full potential. At level 14 and above, the resulting approximants give an energy less than -1 in units of the D25-brane tension, in agreement with recent level-truncation results by Gaiotto and Rastelli. The extrapolated energy continues to decrease below -1 until reaching a minimum near level 26, after which the energy turns around and begins to approach -1 from below. Within the accuracy of this method, these results are completely consistent with an energy which approaches -1 as the level of truncation is taken to be arbitrarily large.Comment: 8 pages, 3 eps figures, Latex; v2: typo correcte

Multilinear Wavelets: A Statistical Shape Space for Human Faces

We present a statistical model for $3$D human faces in varying expression, which decomposes the surface of the face using a wavelet transform, and learns many localized, decorrelated multilinear models on the resulting coefficients. Using this model we are able to reconstruct faces from noisy and occluded $3$D face scans, and facial motion sequences. Accurate reconstruction of face shape is important for applications such as tele-presence and gaming. The localized and multi-scale nature of our model allows for recovery of fine-scale detail while retaining robustness to severe noise and occlusion, and is computationally efficient and scalable. We validate these properties experimentally on challenging data in the form of static scans and motion sequences. We show that in comparison to a global multilinear model, our model better preserves fine detail and is computationally faster, while in comparison to a localized PCA model, our model better handles variation in expression, is faster, and allows us to fix identity parameters for a given subject.Comment: 10 pages, 7 figures; accepted to ECCV 201