A nonextremal Camion basis

AbstractWe construct a 3 × 21 matrix A and Camion basis B of A such that B does not correspond to an extreme point of the convex hull of basic solutions of Ax = b for any b ϵ R3. Computer algebra methods played a critical role in finding both the matrix A and an analytic proof that B is not extremal

A study of rationality of slopeland use in view of land preservation

In recent years, frequent attacks of heavy rain and typhoon have severely devastated the vulnerable mountains of Taiwan; slopelands are artificially disturbed by improper development and utilization. People are getting more aware of the importance of slopeland preservation as well as disaster prevention and mitigation. The government, realizing the criticality of gradually worsened land safety issues, has also set forth the "Draft of National Land Planning Act" and the "Draft of Regulations on Land Preservation Act" in the purposes of rehabilitating the excessively explored ecosystems and diminishing the development extent of environmentally susceptible areas, so as to effectively preserve soil, water, and organism resources and to achieve perpetual development of national lands. "Classification of Slopeland Utilization Limitations" is a critical link to national land preservation. The classification is based on four factors, namely average slope, effective soil depth, soil erosion, and parent rock, with different utilization zones defined as bases of landuse planning. However, current classification results of the environmentally susceptible and disaster-prone mountain lands are mostly defined as suitable for forestry or husbandry. Scattered allocation of these lands results in critical issues such as segmented landuse and impaired landscape and ecotype. It is necessary to re-adjust land resources planning and usage management. Therefore a review of the current standards for classifying slopeland utilization limitations is proposed to facilitate rational allocation of slopeland use. Jhuoshuei River is selected as the scope of the case study, with data of debris flows induced by the typhoon Toraji in 2001 as the training data. Eight susceptibility factors, which include form factor of watershed, integral hypsometric, slope of main stream, density of stream network, density of road network, area ratio of historical landslide, and area ratio of triggered landslide, together with the total rainfall of the storm event as the triggering factor, are selected for creating the debris flow susceptibility model by employing the logistic regression within the multivariate geostatistics analysis. This model interprets the curve of success ratio of debris flows triggered by typhoon Toraji, of which the area under the curve is as high as 74.3%. The debris flow susceptibility model created in the study takes the Feng-Chiu section of Sinyi Township, Nantou County, Taiwan within the Jhuoshuei River as the scope of research. GIS technology has been applied in the feasibility study of classification standards. New concepts have been further proposed in view of national land preservation addressing the medium and high elevation disaster-prone areas that are not suitable for agricultural use, for standard revision reference

Using a Threading-Followed-by-Swelling Approach to Synthesize 2 Rotaxanes

We have developed a "threading-followed-by-swelling" protocol to synthesize [2]rotaxanes efficiently and atom economically. Our protocol employs cis-1-[(Z)-alk-1'enyl]-2-vinylcyclopropane units as the termini of the threadlike components; these end groups are converted into more-sizable cycloheptadiene motifs, which function as stopper units, through Cope rearrangements at elevated temperature. We used this approach to synthesize [2]rotaxanes in good yield from [2]pseudorotaxanes featuring either one or two swellable termini to interlock three different types of macrocycle. The chiral centers created by the swelling process were "erased" by hydrogenating the cycloheptadiene termini into the corresponding cycloheptane units, affording achiral molecular [2]rotaxanes as the only final products

B --> Phi K_S and Supersymmetry

The rare decay B --> Phi K_S is a well-known probe of physics beyond the Standard Model because it arises only through loop effects yet has the same time-dependent CP asymmetry as B --> Psi K_S. Motivated by recent data suggesting new physics in B --> Phi K_S, we look to supersymmetry for possible explanations, including contributions mediated by gluino loops and by Higgs bosons. Chirality-preserving LL and RR gluino contributions are generically small, unless gluinos and squarks masses are close to the current lower bounds. Higgs contributions are also too small to explain a large asymmetry if we impose the current upper limit on B(B_s --> mu mu). On the other hand, chirality-flipping LR and RL gluino contributions can provide sizable effects and while remaining consistent with related results in B --> Psi K_S, Delta M_s, B --> X_s gamma and other processes. We discuss how the LR and RL insertions can be distinguished using other observables, and we provide a string-based model and other estimates to show that the needed sizes of mass insertions are reasonable.Comment: 33 pages, 32 figures, Updated version for PRD. Includes discussions of other recent works on this topic. Added discussions & plots for gluino mass dependence and effects of theoretical uncertaintie

Charmed Exotics in Heavy Ion Collisions

Based on the color-spin interaction in diquarks, we argue that charmed multiquark hadrons are likely to exist. Because of the appreciable number of charm quarks produced in central nucleus-nucleus collisions at ultrarelativistic energies, production of charmed multiquark hadrons is expected to be enhanced in these collisions. Using both the quark coalescence model and the statistical hadronization model, we estimate the yield of charmed tetraquark meson $T_{cc}$ and pentaquark baryon $\Theta_{cs}$ in heavy ion collisions at RHIC and LHC. We further discuss the decay modes of these charmed exotic hadrons in order to facilitate their detections in experiments

Forced flowering of pineapple (Ananas comosus cv. Tainon 17) in response to cold stress, ethephon and calcium carbide with or without activated charcoal

Ethylene, a gaseous plant hormone, is responsible for the initiation of reproductive development in pineapple. Reproductive development can be forced in pineapple (Ananas comosus var. comosus) throughout the year with ethylene. Inhibition of natural flowering initiation with aviglycine [(S)-trans-2-amino-4-(2-aminoethoxy)-3-butenoic acid hydrochloride], an inhibitor of ethylene biosynthesis, provides evidence that reproductive development in response to cold stress and short daylength is also in response to ethylene production. We studied the effect of cold treatment of pineapple on ethylene production and flower induction by applying a short-term cold stress to stem apices. Shoot apices of pineapple treated with ice crystals also produced twice as much ethylene as did those of control plants and significantly more than was produced by "D" leaf basal tissue. Moreover, pineapple plants treated four times with ice crystals or ice water were induced to flower under field conditions and the forcing efficiency, as evaluated by the percentages of inflorescence emergence and fruit harvest, was comparable to forcing with calcium carbide (CaC(2)) and ethephon. In another field experiment two applications of a 1.0% solution of CaC(2) or 0.15% ethephon applied at 48 h intervals was sufficient to force reproductive development of 'Tainon 17'. Furthermore, 0.5 or 1.0% solutions of CaC(2) supplemented with 0.5% activated charcoal (AC) significantly improved the forcing effectiveness of CaC(2). This could/would make it possible to reduce the number or concentration, or both, of CaC(2) required to effect forcing in pineapple

Genomic identification of two Phytobacter diazotrophicus isolates from a neonatal intensive care unit in Singapore

We report the draft genome sequences of two Phytobacter diazotrophicus isolates recovered from a swab specimen from the water faucet located in the Neonatal Intensive Care Unit (ICU), National University Hospital, Singapore. The isolates were misidentified as Cronobacter sakazakii and Klebsiella oxytoca using biochemical methods. Whole-genome sequencing (WGS) was performed to determine their identity

Additive Interaction of Hyperglycemia and Albuminuria on Risk of Ischemic Stroke in Type 2 Diabetes: Hong Kong Diabetes Registry

OBJECTIVE—The study aims to test whether biological interaction between hyperglycemia and albuminuria can explain the inconsistent findings from epidemiological studies and clinical trials about effects of hyperglycemia on stroke in type 2 diabetes

Exploring flavor structure of supersymmetry breaking from rare B decays and unitarity triangle

We study effects of supersymmetric particles in various rare B decay processes as well as in the unitarity triangle analysis. We consider three different supersymmetric models, the minimal supergravity, SU(5) SUSY GUT with right-handed neutrinos, and the minimal supersymmetric standard model with U(2) flavor symmetry. In the SU(5) SUSY GUT with right-handed neutrinos, we consider two cases of the mass matrix of the right-handed neutrinos. We calculate direct and mixing-induced CP asymmetries in the b to s gamma decay and CP asymmetry in B_d to phi K_S as well as the B_s--anti-B_s mixing amplitude for the unitarity triangle analysis in these models. We show that large deviations are possible for the SU(5) SUSY GUT and the U(2) model. The pattern and correlations of deviations from the standard model will be useful to discriminate the different SUSY models in future B experiments.Comment: revtex4, 36 pages, 10 figure