
Overproduction of indole-3-acetic acid in free-living rhizobia induces transcriptional changes resembling those occurring in nodule bacteroids.
Free-living bacteria grown under aerobic conditions were used to investigate, by next-generation RNA sequencing analysis, the transcriptional profiles of Sinorhizobium meliloti wild-type 1021 and its derivative, RD64, overproducing the main auxin indole-3-acetic acid (IAA). Among the upregulated genes in RD64 cells, we detected the main nitrogen-fixation regulator fixJ, the two intermediate regulators fixK and nifA, and several other genes known to be FixJ targets.
Rank-revealing decomposition of symmetric indefinite matrices via block anti-triangular factorization
We present an algorithm for computing a symmetric rank revealing decomposition of a symmetric n x n matrix A, as defined in the work of Hansen & Yalamov [9]: we factorize the original matrix into a product A = QMQ(T), with Q orthogonal and M symmetric and in block form, with one of the blocks containing the dominant information of A, such as its largest eigenvalues.
Asymptotic high order schemes for dissipative hyperbolic systems
We consider finite difference schemes which approximate one-dimensional dissipative hyperbolic systems. Using precise analytical time-decay estimates of the local truncation error, we show that it is possible to introduce some suitable modification in standard upwinding schemes to design schemes which are increasingly accurate for large times when approximating small perturbations of stable asymptotic states, respectively, around stationary solutions and in the diffusion (Chapman-Enskog) limit.
Hierarchical non-negative matrix factorization applied to three-dimensional 3T MRSI data for automatic tissue characterization of the prostate
In this study non-negative matrix factorization (NMF) was hierarchically applied to simulated and in vivo three-dimensional 3 T MRSI data of the prostate to extract patterns for tumour and benign tissue and to visualize their spatial distribution. Our studies show that the hierarchical scheme provides more reliable tissue patterns than those obtained by performing only one NMF level. We compared the performance of three different NMF implementations in terms of pattern detection accuracy and efficiency when embedded into the same kind of hierarchical scheme.
Linear and anomalous front propagation in systems with non-Gaussian diffusion: The importance of tails
We investigate front propagation in systems with diffusive and subdiffusive behavior. The scaling behavior of moments of the diffusive problem, both in the standard and in the anomalous cases, is not enough to determine the features of the reactive front. In fact, the shape of the bulk of the probability distribution of the transport process, which determines the diffusive properties, is important just for preasymptotic behavior of front propagation, while the precise shape of the tails of the probability distribution determines asymptotic behavior of front propagation.
Turning ability analysis of a fully appended twin screw vessel by CFD. Part II: Single vs. twin rudder configuration
In the present paper, the analysis of the turning capability of the naval supply vessel presented in Part I
(Broglia et al., 2015) is continued with different stern appendages, namely twin rudder and centreline skeg.
The main purpose of the analysis is to assess the capability of an in-house CFD tool in capturing the
different manoeuvring characteristics of the ship hulls; the test case is challenging, as the difference be-
tween the two configurations lies in the complex flow structure related to rudder-propeller interactions.
Moreover, although the twin rudder solution slightly improves the
Paradoxical ratcheting in cornstarch
In this paper, we demonstrate that vertically vibrating a plate in a cornstarch suspension causes the suspension to vigorously ratchet up the plate. We show that this is a necessary consequence of the fact that cornstarch in water is shear thickening: when the plate moves up it opposes gravity and so the fluid stiffens; when it moves down it works with gravity and so the fluid flows. This produces asymmetric ratcheting that opposes gravity.





