Reduced-dimension clustering for vegetation segmentation

Segmentation of vegetation is a critical step in using machine vision for field automation tasks. A new method called reduced-dimensionclustering (RDC) was developed based on theoretical considerations about the color distribution of field images. RDC performed unsupervised classification of pixels in field images into vegetation and background classes. Bayes classifiers were then trained and used for vegetation segmentation. The performance of the classifiers trained using the RDC method was compared with that of other segmentation methods. The RDC method produced segmentation performance that was consistently high, with average segmentation success rates of 89.6% and 91.9% across both cloudy and sunny lighting conditions, respectively. Statistical analyses of segmentation performance coupled with three-dimensional visualization of classifier decision surfaces produced insight into why classifier performance varied across the methods. These results should lead to improvements in segmentation methods for field images acquired under variable lighting conditions

Narrow-band and derivative-based vegetation indices for hyperspectral data

Hyperspectral remote sensing imagery was collected over a soybean field in central Illinois in mid-June 2001 before canopy closure. Estimates of percent vegetation cover were generated through the processing of RGB (red, green, blue) digital images collected on the ground with an automated crop mapping system. A comparative study was completed to test the ability of broad-band, narrow-band, and derivative-based vegetation indices to predict percent soybean cover at levels less than 70%. Though remote sensing imagery is commonly analysed using reference data collected at random points over a scene of interest, the analysis of the hyperspectral imagery in this research was performed on a pixel-by-pixel basis over the field area covered by the automated crop mapping system. Narrow-band and derivative-based indices utilizing the finer spectral detail of hyperspectral data performed better than the older broad-band indices developed for use with multispectral data. Specifically, second-derivative indices measuring the curvature in the green region (514-556 nm), longer wavelength red region (640-694 nm), and short wavelength NIR (712-778 nm) performed well. Narrow-band indices, based on the standard ratio index equations, which used values from the blue (472-490 nm) and green (514-550 nm) regions, also performed well for many of the datasets. The performance of all indices was shown to suffer over areas of brighter soil background, and the use of ratio-based narrow-band indices that did not incorporate NIR reflectance values performed best in this cas

Pbx Regulates Patterning of the Cerebral Cortex in Progenitors and Postmitotic Neurons

SummaryWe demonstrate using conditional mutagenesis that Pbx1, with and without Pbx2+/− sensitization, regulates regional identity and laminar patterning of the developing mouse neocortex in cortical progenitors (Emx1-Cre) and in newly generated neurons (Nex1-Cre). Pbx1/2 mutants have three salient molecular phenotypes of cortical regional and laminar organization: hypoplasia of the frontal cortex, ventral expansion of the dorsomedial cortex, and ventral expansion of Reelin expression in the cortical plate of the frontal cortex, concomitant with an inversion of cortical layering in the rostral cortex. Molecular analyses, including PBX ChIP-seq, provide evidence that PBX promotes frontal cortex identity by repressing genes that promote dorsocaudal fate

Statistical mechanics of RNA folding: importance of alphabet size

We construct a minimalist model of RNA secondary-structure formation and use it to study the mapping from sequence to structure. There are strong, qualitative differences between two-letter and four or six-letter alphabets. With only two kinds of bases, there are many alternate folding configurations, yielding thermodynamically stable ground-states only for a small set of structures of high designability, i.e., total number of associated sequences. In contrast, sequences made from four bases, as found in nature, or six bases have far fewer competing folding configurations, resulting in a much greater average stability of the ground state.Comment: 7 figures; uses revtex

Subjective memory complaints are associated with brain activation supporting successful memory encoding

Neuro Imaging Researc

Solidification behavior of intensively sheared hypoeutectic Al-Si alloy liquid

The official published version of this article can be found at the link below.The effect of the processing temperature on the microstructural and mechanical properties of Al-Si (hypoeutectic) alloy solidified from intensively sheared liquid metal has been investigated systematically. Intensive shearing gives a significant refinement in grain size and intermetallic particle size. It also is observed that the morphology of intermetallics, defect bands, and microscopic defects in high-pressure die cast components are affected by intensive shearing the liquid metal. We attempt to discuss the possible mechanism for these effects.Funded by the EPSRC

Conductive films based on composite polymers containing ionic liquids absorbed on crosslinked polymeric ionic-like liquids (SILLPs)

Polymerization of styrenic monomers containing imidazolium subunits in the presence of crosslinking monomers and using ionic liquids (ILs) as porogenic agents provides composite materials with excellent mechanical properties and displaying conductivities that are in the same order of magnitude than those shown by bulk ILs. This approach allows the use of high crosslinking degrees and low IL-loadings without compromising the required properties of the resulting composites. Besides, no appreciable leaching of the bulk IL component is detected.Financial support by Ministerio de Ciencia e Innovacion (CTQ2011-28903-C02-01 and SP-ENE-20120718), Generalitat Valenciana (PROMETEO/2012/020) and Universitat Jaume I (P11B2013-38) is acknowledged.Altava Benito, B.; Compañ Moreno, V.; Andrio Balado, A.; Del Castillo Davila, LF.; Mollá Romano, S.; Burguete, MI.; García-Verdugo Cepeda, E.... (2015). Conductive films based on composite polymers containing ionic liquids absorbed on crosslinked polymeric ionic-like liquids (SILLPs). Polymer. 72:69-81. https://doi.org/10.1016/j.polymer.2015.07.009S69817

Partial Wave Analysis of J/ψ→γ(K+K−π+π−)J/\psi \to \gamma (K^+K^-\pi^+\pi^-)

BES data on $J/\psi \to \gamma (K^+K^-\pi^+\pi^-)$ are presented. The $K^*\bar K^*$ contribution peaks strongly near threshold. It is fitted with a broad $0^{-+}$ resonance with mass $M = 1800 \pm 100$ MeV, width $\Gamma = 500 \pm 200$ MeV. A broad $2^{++}$ resonance peaking at 2020 MeV is also required with width $\sim 500$ MeV. There is further evidence for a $2^{-+}$ component peaking at 2.55 GeV. The non-$K^*\bar K^*$ contribution is close to phase space; it peaks at 2.6 GeV and is very different from $K^{*}\bar{K^{*}}$.Comment: 15 pages, 6 figures, 1 table, Submitted to PL