If the tensor-to-scalar ratio r of cosmological perturbations takes a large value r ∼ 0.1, which may be inferred from the recent BICEP2 result, we can hope to determine thermal history, in particular, the reheating temperature, TR, after inflation by space-based laser interferometers. It is shown that upgraded and upshifted versions of DECIGO may be able to determine TR if it lies in the …

Zooplankton diel vertical migration (DVM) is often explained as a balance between predator avoidance and resource acquisition. However, recent studies suggest that ultraviolet radiation (UV) may also be important in driving zooplankton DVM in some systems. Williamson et al. (Williamson et al., 2011) proposed the “transparency-regulator hypothesis,” which integrates UV into our current under…

We discuss an inverse source formulation aimed at focusing wave energy produced by ground surface sources to target subsurface poroelastic formations. The intent of the focusing is to facilitate or enhance the mobility of oil entrapped within the target formation. The underlying forwardwave propagation problem is cast in two spatial dimensions for a heterogeneous poroelastic target embedded wit…

A method is outlined by means of which it is possible to estimate high-resolution vertical displacements due to an earthquake even in the case where high-resolution topography is lacking before the earthquake. This result can be achieved by combining a highly accurate, post-event digital elevation model (DEM), for example lidar, with archived satellite imagery. The method is illustrated by calc…

Local earthquake tomography is a non-linear and non-unique inverse problem that uses event arrival times to solve for the spatial distribution of elastic properties. The typical approach is to apply iterative linearization and derive a preferred solution, but such solutions are biased by a number of subjective choices: the starting model that is iteratively adjusted, the degree of regularizatio…

To test the paradigm that large-bodied zooplankton species dominate in fishless lakes, we evaluated crustacean zooplankton composition of 53 fishless boreal lakes across a broad geographic scale (north-west Saskatchewan, Canada) in relation to contemporary environmental factors. Lake productivity, acid–base status and intensity of invertebrate predation were the three major environmental filt…

Epithelial–mesenchymal transition (EMT) plays a critical role in promoting cancer metastasis. In this study, cancer EMT is considered as an overall structural change in the gene regulatory network (GRN), and its essential features are elucidated by the network biology approach. We first defined the state space of GRN as a set of all possible activation patterns of GRN, and then introduced t…

There has been extensive work on seismic source localization, going as far back as Geiger’s 1912 paper, that is based on least-squares fitting of arrival times. The primary advantage of time-based methods over waveform-based methods (e.g. reverse-time migration and beam forming) is that simulated arrival times are considerably more reliable than simulated waveforms, especially in the context…

Tahun Terbit

2009

How fast should animals move when trying to survive? Although many studies have examined how fast animals can move, the fastest speed is not always best. For example, an individual escaping from a predator must run fast enough to escape, but not so fast that it slips and falls. To explore this idea, we developed a simple mathematical model that predicts the optimal speed for an individual runni…