3,272 research outputs found
Monotone Grid Drawings of Planar Graphs
A monotone drawing of a planar graph is a planar straight-line drawing of
where a monotone path exists between every pair of vertices of in some
direction. Recently monotone drawings of planar graphs have been proposed as a
new standard for visualizing graphs. A monotone drawing of a planar graph is a
monotone grid drawing if every vertex in the drawing is drawn on a grid point.
In this paper we study monotone grid drawings of planar graphs in a variable
embedding setting. We show that every connected planar graph of vertices
has a monotone grid drawing on a grid of size , and such a
drawing can be found in O(n) time
Tomato yellow leaf curl virus (TYLCV) alters the phytochemical constituents in tomato fruits.
An investigation was conducted in order to evaluate the responses of field grown tomato varieties (Marglove and Roma VF) to tomato yellow leaf curl virus (TYLCV). Fruit samples from the virus-infected and uninfected plants were collected at 20 (early stage), 40 (intermediate stage) and 60 days (ripening stage) after anthesis. Results showed higher virus RNA content in fruits of infected plants at early (42.48 to 38.24%) and intermediate stages (34.35 to 19.57%). There was a substantial decrease in DNA content (27.27 and 21.05%) at early and (23.08 and 43.75%) at intermediate stages of both Marglove and Roma VF, compared to the control, respectively. Similarly, indole acetic acid content was also decreased (27.08 and 24.29%) in fruits of virus-infected Marglove and Roma VF, respectively. The free ascorbic acid content was found lower (35.29 to 51.52%), while combined ascorbic acid was higher (13.91 to 33.33%) in both varieties. Neither the responses of individual organic acids nor their concentrations in fruits of infected and control plants were identical. Fumaric acid was not detected either in fruits of infected plants of Marglove or in healthy and infected Roma VF. Individual fruit weight and fruit numbers per plant were lower in the virus-infected plants. This study indicates that the yield of infected tomato plants could be reduced by the infection of TYLCV due to the changes in the concentrations of phytochemical constituents. This suggests that monitoring and management of TYLCV incidence is crucial for yield and quality optimization of field grown tomato
Anisotropic magnetic properties of CeAgGe single crystal
In order to investigate the anisotropic magnetic properties of
CeAgGe, we have successfully grown the single crystals, for the first
time, by high temperature solution growth (flux) method. We have performed a
detailed study of the grown single crystals by measuring their electrical
resistivity, magnetic susceptibility, magnetization, specific heat and
magnetoresistance. A clear anisotropy and an antiferromagnetic transition at
= 4.6 K have been observed in the magnetic properties. The magnetic
entropy reaches ln 4 at 20 K indicating that the ground state and the first
excited state are very closely spaced (a quasi-quartet state). From the
specific heat measurements and crystalline electric field (CEF) analysis of the
magnetic susceptibility, we have found the level splitting energies as 5 K and
130 K. The magnetization measurements reveal that the a-axis is the easy axis
of magnetization and the saturation moment is = 1.6 /Ce, corroborating the previous neutron diffraction measurements on a
polycrystalline sample.Comment: Submitted to Phys. Rev.
Microleakage of composite resin restorations in cervical cavities prepared by Er,Cr: YSGG laser radiation
Background: Evaluation of microleakage is important for assessing the success of new methods for surface preparation and new adhesive restorative materials. The aim of this laboratory study was to assess microleakage at the margins of composite restorations in Er,Cr:YSGG laser prepared cavities on the cervical aspects of teeth by means of dye penetration, and compare this with conventionally prepared and conditioned cavities. Methods: Class V cavities were produced on sound extracted human teeth, which had been assigned randomly to one of three groups (N = 10 each), as follows: Group 1 – prepared using a diamond cylindrical bur and then treated with 37% phosphoric acid; Group 2 – irradiated with an Er,Cr:YSGG laser (Biolase Waterlase) and then treated with 37% phosphoric acid; Group 3 – irradiated only with the laser. After application of bonding agent (Excite, Ivoclar Vivadent), all cavities were restored with composite resin (Heliomolar). After polishing the restorations, the teeth were thermocycled from 5–50°C for 500 cycles. Dye leakage was assessed after immersion in methylene blue, by examining longitudinal sections in a stereomicroscope at ×30 magnification. Results: The extent of dye penetration was lowest in the laser only group (Group 3). Penetration of dye to dentine and axial walls occurred in 80 per cent of conventionally prepared (bur + acid) specimens, but in the laser group, dye penetration to the axial wall occurred in only 30 per cent of cases. There was a strong statistical association between treatment group and the distribution of microleakage scores (Chi-square, P = 0.0023). Conclusions: For Class V cavities, with the adhesive materials employed, higher microleakage occurs with phosphoric acid etching of bur- or laser-cut surfaces, than with the surface created by use of the laser alone without additional conditioning
Antidiabetic Effects of Momordica Charantia (Karela) in Male Long Evans Rat
The hypoglycemic effect of Momordica charantia (Karela) has been reported from many laboratories. To our knowledge, the underlying biochemical mechanism of action of this important clinical effect has not been reported. During the course of investigation of this aspect of the herbal fruit, it was reported from our laboratory that ethanolic extract of Momordica charantia suppressed gluconeogenesis in normal and streptozotocin (STZ) induced diabetic rats by depressing the hepatic gluconeogenic enzymes fructose-1,6-bisphosphatase and glucose-6-phosphatase. The herbal extract had also enhanced the activity of glucose-6-phosphate dehydrogenase, the rate-limiting enzyme of hexose monophosphate shunt (a pathway for the oxidation of glucose)
Crystal-field level inversion in lightly Mn-doped Sr3Ru2O7
Sr3(Ru1-xMnx)2O7, in which 4d-Ru is substituted by the more localized 3d-Mn,
is studied by x-ray dichroism and spin-resolved density functional theory. We
find that Mn impurities do not exhibit the same 4+ valence of Ru, but act as 3+
acceptors; the extra eg electron occupies the in-plane 3dx2-y2 orbital instead
of the expected out-of-plane 3d3z2-r2. We propose that the 3d-4d interplay, via
the ligand oxygen orbitals, is responsible for this crystal-field level
inversion and the material's transition to an antiferromagnetic, possibly
orbitally-ordered, low-temperature state.Comment: A high-resolution version can be found at
http://www.physics.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Articles/MnSr3Ru2O7_XAS.pd
Mott versus Slater-type metal-insulator transition in Mn-substituted Sr3Ru2O7
We present a temperature-dependent x-ray absorption (XAS) and resonant
elastic x-ray scattering (REXS) study of the metal-insulator transition (MIT)
in Sr3(Ru1-xMnx)2O7. The XAS results reveal that the MIT drives the onset of
local antiferromagnetic correlations around the Mn impurities, a precursor of
the long-range antiferromagnetism detected by REXS at T_order<T_MIT. This
establishes that the MIT is of the Mott-type (electronic correlations) as
opposed to Slater-type (magnetic order). While this behavior is induced by Mn
impurities, the (1/4,1/4,0) order exists for a wide range of Mn concentrations,
and points to an inherent instability of the parent compound.Comment: In press. A high-resolution version can be found at
http://www.phas.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Articles/MnSRO_REXS.pd
Recommended from our members
Effect of varying skin surface electrode position on electroretinogram responses recorded using a handheld stimulating and recording system
- …