TYPE II MADS-BOX GENES ASSOCIATED WITH POPLAR APICAL BUD DEVELOPMENT AND DORMANCY

MADS-box transcription factors regulate the development of vegetative and reproductive organs in plants. Little is known about the role of MADS-box genes in tree development. Using phylogenetic analysis, 57 putative type II MADS-box genes representing 14 functional classes were identified in the Populus trichocarpa genome. cDNA sequencing of the poplar type II MADS-box genes indicates that 28.1% of the transcripts differed in the intron-exon structures predicted in the genome database and 19.3% of the transcripts appear to be alternatively spliced. The majority of the poplar type II MADS-box genes were expressed in a wide variety of tissues including shoot apices, leaves, bark, xylem, root, and floral tissues and in shoot apices during bud development and dormancy. These results indicate that poplar MADS-box genes have diverse regulatory roles in a broad range of tissues and developmental processes. Six poplar FLC-like genes, PtFLC1-PtFLC6, were identified in the poplar genome and expression of all six genes was detected in poplar shoot apices. The expression of one gene, PtFLC2, declined in apical buds during SD photoperiod and low temperature induced dormancy development suggesting a role in bud dormancy and may represent an analogous regulatory mechanism to the down-regulation of FLC during vernalization in Arabidopsis. In addition, several PtFLC2 splice isoforms (PtFLC2as1-9) were identified that were associated with the later stages of bud dormancy. Overexpression of the PtFLC2as1 isoform delayed photoperiod induced apical bud development and bud dormancy, growth cessation, and leaf senescence while overexpression of the PtFLC2as2 isoform appeared to accelerate bud development and dormancy and reduce the amount of chilling required to overcome dormancy. These findings suggest that PtFLC2, unlike Arabidopsis FLC, could be an integration point for both photoperiod and cold signals that regulate bud development and dormancy. These results also suggest that in addition to transcriptional regulation, that cold-mediated production of PtFLC2 splicing isoforms may have an important regulatory role in bud dormancy. The regulated production of splicing isoforms could regulate bud dormancy either by dominate negative interactions, by forming different protein complexes or regulating different pathways that regulate growth, dormancy, and dormancy release

Color-complexity enabled exhaustive color-dots identification and spatial patterns testing in images

Targeted color-dots with varying shapes and sizes in images are first exhaustively identified, and then their multiscale 2D geometric patterns are extracted for testing spatial uniformness in a progressive fashion. Based on color theory in physics, we develop a new color-identification algorithm relying on highly associative relations among the three color-coordinates: RGB or HSV. Such high associations critically imply low color-complexity of a color image, and renders potentials of exhaustive identification of targeted color-dots of all shapes and sizes. Via heterogeneous shaded regions and lighting conditions, our algorithm is shown being robust, practical and efficient comparing with the popular Contour and OpenCV approaches. Upon all identified color-pixels, we form color-dots as individually connected networks with shapes and sizes. We construct minimum spanning trees (MST) as spatial geometries of dot-collectives of various size-scales. Given a size-scale, the distribution of distances between immediate neighbors in the observed MST is extracted, so do many simulated MSTs under the spatial uniformness assumption. We devise a new algorithm for testing 2D spatial uniformness based on a Hierarchical clustering tree upon all involving MSTs. Our developments are illustrated on images obtained by mimicking chemical spraying via drone in Precision Agriculture.Comment: 21 pages, 21 figure

An Elusive Vector Dark Matter

Even though the sensitivity of direct dark matter search experiments reach the level about $10^{-45}~{\rm cm}^2$, there is no confident signal of dark matter been observed. We point out that, if dark matter is a vector boson, the null result in direct dark matter search experiments may due to the destructive effects in dark-matter-nucleon elastic scattering. We illustrate the scenario using a modified Higgs portal model that includes exotic quarks. The significant cancellation can occur for certain mass gap between heavy quark and dark matter. As a result, the spin-independent dark-matter-nucleon elastic scattering is so suppressed that the future direct search experiments can hardly observe the signal of dark matter.Comment: 11 pages, 5 figure

General relations of heavy quark-antiquark potentials induced by reparameterization invariance

A set of general relations between the spin-independent and spin-dependent potentials of heavy quark and anti-quark interactions are derived from reparameterization invariance in the Heavy Quark Effective Theory. It covers the Gromes relation and includes some new interesting relations which are useful in understanding the spin-independent and spin-dependent relativistic corrections to the leading order nonrelativistic potential.Comment: 11 pages, TUIMP-TH-93/54, CCAST-93-3

THE EFFECTS OF CHARACTERISTICS OF CORPORATE BLOG ON TOURISTS’ LODGING INTENTION: AN EXAMPLE OF BED AND BREAKFAST

Tourists may rely on external information to make various decisions. By understanding the relation between information source characteristics and decision making, tourist operators can improve their communication performance and marketing efforts. Some businesses use corporate blog as a communication platform to engage their customers with the companies. Researches about the causal relationship between corporate blog and business marketing performance, yet, are scant. A theoretical model was built based on a set of distinct characteristics of corporate blogs identified from existing literature. A questionnaire survey was conducted to test this model. Based on 143 samples collected, this study found that vividness, interactivity of the blogs impact B&Bs’ lodging intention via the mediation of the sense of intimacy; and that direction of product reviews posted in the blogs directly impacts the lodging intention. Finally, managerial and academic implications are offered

BIOMECHANICAL ANALYSIS OF BADMINTON FOREHAND NET SHOTS

The purpose of this study was to compare the upper extremity kinematics variables of badminton forehand dab shot, stab shot and cross court net shot. The participants were eight elite collegiate male players in Taiwan. The kinematical data were collected by Vicon system (250Hz) and the Visual 3D software was used to analyze the variables. The results indicated that the elite badminton players perfomed dab net shot with less angular velocity in racket upper limb joints. They performed the stab net shot with faster angular velocity in forearm supination and wrist ulnar flexion. The cross court net shot had greatest angular velocity in shoulder internal rotation, forearm pronation and the least distance between the contact point and the mid-line of body