Elliptical Area Research Articles

Preimaginal Survival and Development ofColeomegilla maculataandHippodamia convergens(Coleoptera: Coccinellidae) Reared onAcyrthosiphon pisum:Effects of Host Plants

Coleomegilla maculata (DeGeer) and Hippodamia convergens Guerin-Meneville larvae were supplied daily with ≈1.2, 2.2, 4.3, 8.2, or 16.4 mg of Acyrthosiphon pisum Harris reared on either alfalfa Medicago sativa L. (‘OK08’) or faba beans Vicia faba L. (‘Windsor’). Myristic acid and total fatty acid content (μg/mg aphid fresh weight) were 6.3 and 2.7 times greater, respectively, in pea aphids reared on alfalfa as compared with faba beans, resulting in a 1.17-fold increase in caloric content. Higher survival ratios were observed for both C. maculata and H. convergens supplied with low daily prey levels of pea aphids reared on alfalfa versus faba beans, but no differences were observed at higher prey levels. When pea aphids reared on alfalfa were supplied to C. maculata and H. convergens larvae at low prey levels, preimaginal developmental times were significantly reduced compared with those supplied with pea aphids reared on faba beans at the same prey levels. At higher daily pea aphid levels, C. maculata and H. convergens developmental times were not significantly different between host plants. At lower daily prey levels, C. maculata and H. convergens elliptical body area was larger when supplied with pea aphids reared on alfalfa, but body areas were similar at higher daily prey levels. Convergence of survival ratios, developmental times, and elliptical body areas for C. maculata and H. convergens at high (less limiting) prey levels supports the hypothesis that differences in prey nutritional value between pea aphids reared on alfalfa versus faba beans are quantitative and appear to be primarily influenced by differences in pea aphid myristic acid content.

Local material removal mechanism considering curvature effect in the polishing process of the small aspherical lens die

This paper describes a method to obtain the local removal rate for the polishing process of the small aspherical lens die using a spherical tool. When the small spherical polishing tool traverses an aspherical surface, non-uniform polishing area and local removal rate are locally generated around the contacting points according to the curvature change of an aspherical surface. Therefore, an aspherical surface is divided into multiple patches and the local removal rate on the patches is calculated semi-empirically from the Preston equation. Formation of the elliptical polishing area is confirmed experimentally and the Preston coefficient is calculated from the central removal depth and dwell time that has a linear relation with the local removal depth. Finally, using the equivalent radius of two contact bodies, the curvature effect of an aspherical surface on the polishing area is explained.

High resolution seismic-reflection imaging of shallow deformation beneath the northeast margin of the Manila high at Big Lake, Arkansas

The Manila high, an elliptical area 19km long (N–S) by 6km wide (E–W) located west-southwest of Big Lake, Arkansas, has less than 3m of topographic relief. Geomorphic, stratigraphic and chronology data indicate that Big Lake formed during at least two periods of Holocene uplift and subsequent damming of the south-flowing Little River. Age data of an organic mat located at the base of an upper lacustrine deposit indicates an abrupt, possibly tectonic, formation of the present Big Lake between ad 1640 and 1950.We acquired 7km of high-resolution seismic-reflection data across the northeastern margin of the Manila high to examine its near-surface bedrock structure and possible association with underlying structures such as the Blytheville arch. Sense of displacement and character of imaged faults support interpretations for either a northwest trending, 1.5km-wide, block of uplifted strata or a series of parallel northeast-trending faults that bound horst and graben structures. We interpret deformation of the Manila high to result from faulting generated by the reactivation of right-lateral strike-slip fault motion along this portion of the Blytheville arch. The most recent uplift of the Manila high may have occurred during the December 16, 1811, New Madrid earthquake.

Eddy covariance measurement of CO 2 flux to the atmosphere from an area of high volcanogenic emissions, Mammoth Mountain, California

Three pilot studies were performed to assess application of the eddy covariance micrometeorological method in the measurement of carbon dioxide (CO 2) flux of volcanic origin. The selected study area is one of high diffuse CO 2 emission on Mammoth Mountain, CA. Because terrain and source characteristics make this a complex setting for this type of measurement, added consideration was given to source area and upwind fetch. Footprint analysis suggests that the eddy covariance measurements were representative of an upwind elliptical source area (3.8×10 3 m 2) which can vary with mean wind direction, surface roughness, and atmospheric stability. CO 2 flux averaged 8–16 mg m −2 s −1 (0.7–1.4 kg m −2 day −1). Eddy covariance measurements of flux were compared with surface chamber measurements made in separate studies [Geophys. Res. Lett. 25 (1998a) 1947; EOS Trans. 79 (1998) F941.] and were found to be similar.

Zur Auswirkung der Hangneigungskorrektur auf Schätzwerte im Schweizerischen Landesforstinventar (LFI) | Investigation of the effect of the slope correction method as applied in the Swiss National Forest Inventory of estimates

For forest inventories on slopes, it is necessary to correct the test areas, because the circular areas, when projected, become elliptical. Based on 93 samples from the Swiss National Forest Inventory (FNI), it was determined whether the simplified method, which increases the radius to match that of the elliptical area, leads to a distortion of the results. An average deviation of 2% was found between the FNI estimated values and the actual values for the basal area and the number of stems. For estimations of smaller units, greater distortions of the results are expected.

Second-harmonic generation using an <italic>a</italic> axis <inline-formula><roman>Nd:MgO:LiNbO</roman><sub><roman>3</roman></sub></inline-formula> single crystal fiber with Mg-ion indiffused cladding

We report the implementation of a low-loss core-cladding waveguide structure of an a axis Nd:MgO:LiNbO3 single-crystal fiber with a step refractive index profile and the demonstration of a frequency- doubled laser made from such a cladded crystal fiber. The laser-heated pedestal-grown a axis single-crystal fiber, with an elliptical crosssectional area of 200x 150?m, is further shown with a Mg ion indiffusion process. Electron probe microanalysis is used to measure the Mg ion concentration distribution in the Mg-diffused layer. After several trials, diffusion parameters suitable for achieving a core-cladding waveguide structure with a step refractive index profile are obtained. The optical and structural properties of the cladded crystal fibers are also characterized. Room-temperature second-harmonic generation with such a cladded crystal fiber is demonstrated. At room temperature, cw green laser output with a power of 10 ?W at the wavelength of 0.532 ?m is achieved. The origin of the relatively low conversion efficiency is discussed.

A study on barrelling in magnesium alloy solid cylinders during cold upset forming

Experiments were carried out to generate data on the upset forming of circular solid cylinders of hot-rolled magnesium alloy ZM-21. During the experimental investigation, the magnesium alloy cylinders were observed to show a change from a circular contact area on the top and bottom surfaces to an elliptical surface area. Calculations were made on the assumptions that the curvature of the barrel surface followed the geometry of both circular and elliptical arcs. It was observed that the measured radius of curvature of the barrel exhibited a straight-line relationship with a new geometrical shape factor, irrespective of the orientations, i.e., irrespective of whether the specimens were machined in the rolling, transverse or thickness direction of the hot-rolled plate. Further, empirical relationships were found to exist between the measured radius of curvature of the barrel and other variables such as the hydrostatic stress and the stress-ratio parameter.

Histology of skin of the amphibious esh,periophthalmus modestus

Structure of the skin in amphibious fish, Periophthalmus modestus, was described in relation to cutaneous respiration. The epidermis has no gland cell. The epidermis consists of three regions: outermost layer of one to five layers of flattened epithelial cells, middle layer of swollen epithelial cells instead of glandular cells and stratum germinativum of cuboidal cells. There are numerous blood capillaries in the outermost layer of the epidermis and diffusion distance between the blood of capillaries and the epidermis is about 1.4 μm. The middle layer of the epidermis appears to be a web‐like structure due to the swollen epithelial cells. The stratum germinativum has a well‐developed lymphatic space containing lymphocytes. There are numerous blood capillaries and elliptical area with acid mucopolysaccharides in stratum laxum of the dermis. The skin of Periophthalmus modestus may be an accessory respiratory organ for oxygen uptake during terrestrial or aquatic life.

LASER THERAPY IN THE TREATMENT OF DENTAL HYPERSENSITIVITY ∼A Histologic Study And Clinical Application

Dentinal hypersensitivity has been studied for several years. It is reported as a strikingly painful condition that originates from the exposure of dentinal tubuli when the thickness of the enamel or cement is significantly reduced. Usually the exposed area is subjected to several kinds of stimuli, resulting in sharp acute pain. The aim of this study was to evaluate the efficacy of low level laser therapy (LLLT) in the treatment of patients with dentinal hypersensitivity. A total of 1102 teeth of 388 patients were treated with LLLT between 1995-2000. Ninety-eight males and 290 females aged 30 to 45 years old were treated. For LLLT, a 780nm continuous wave diode laser was used at an output of 40mW, elliptical area of the beam, 2mm2, and exposure time per point of 25s. This corresponds to an equivalent dose of 50 J/cm2 at each point (considering the area of the spot). If a 1 cm2 area is considered, the total dose per tooth was 4J/cm2. With the 830nm CW 50mW diode laser, the elliptical area of the beam was 2mm2, and exposure time per point was 20s. This corresponds to an equivalent dose of 50J/cm2 at each point (considering the area of the spot). If a 1cm2 area is considered, the total dose per tooth was 4J/cm2. The results showed 403 (36.57%) out of 1102 teeth required a single session for complete remission of the symptom, 255 (23.14%) needed two sessions; 182 (16.51 %) three sessions; 107 (9.7%) four sessions; and 59 (5.35%) five sessions. Ninety-six (8.71%) did not respond to LLLT and the patients were re-assessed and treatment changed. The more affected tooth was the lower premolar (301 - 27.4%), followed by lower molars (163 - 14.8%), upper premolar (149 - 13.5%), lower incisive (148 - 13.4%), upper canine (119 - 10.7%), upper incisive (108 - 9.9%), lower canine (62 - 5.6%), and upper molars (52 - 4.7%). The result of the present investigation demonstrates that LLLT, when used with the correct irradiation parameters, is effective in treating dentinal hypersensitivity, as it quickly reduces pain and maintains a prolonged pain-free status in 91.27% of the cases. Previous studies carried out by the authors examined the histological reaction of the dentinal pulp in rats after application of LLLT. The LLLT was shown to be effective in stimulating odontoblasts, producing repaired dentine and closing dentine tubuli.

Mapping the rupture process of moderate earthquakes by inverting accelerograms

We present a waveform inversion method that uses recordings of small events as Green's functions to map the rupture growth of moderate earthquakes. The method fits P and S waveforms from many stations simultaneously in an iterative procedure to estimate the subevent rupture time and amplitude relative to the Green's function event. We invert the accelerograms written by two moderate Parkfield earthquakes using smaller events as Green's functions. The first earthquake (M = 4.6) occurred on November 14, 1993, at a depth of 11 km under Middle Mountain, in the assumed preparation zone for the next Parkfield main shock. The second earthquake (M = 4.7) occurred on December 20, 1994, some 6 km to the southeast, at a depth of 9 km on a section of the San Andreas fault with no previous microseismicity and little inferred coseismic slip in the 1966 Parkfield earthquake. The inversion results are strikingly different for the two events. The average stress release in the 1993 event was 50 bars, distributed over a geometrically complex area of 0.9 km2. The average stress release in the 1994 event was only 6 bars, distributed over a roughly elliptical area of 20 km2. The ruptures of both events appear to grow spasmodically into relatively complex shapes: the inversion only constrains the ruptures to grow more slowly than the S wave velocity but does not use smoothness constraints.

Design for Donor Strip

Examination of elliptical donor strips reveals a significantly increased incidence of transected follicles at the tapered extremities (relative to other parts). This is believed to be an unavoidable consequence of elliptical donor area excision. The donor strip excision pattern diagramed below was

Seedling and Sprout Response to Slash‐and‐Burn Agriculture in a Tropical Deciduous Forest1

ABSTRACTSurvival and growth of seedlings and sprouts were assessed in three plots for 16 mo following the slashing and burning of a tropical deciduous forest in Jalisco, Mexico. We encountered a total of 47 species: 21 seedling species and 35 sprout species. Calliandra formosa and Piptadenia flava were the most common seedling species; Bursera arborea, Cordia alliodora, and Piptadenia constricta were the most common sprouts. Colubrina triflora, Diphysa occidentalis, and Cnidoscolus spinosus had limited sprouting ability. Twenty‐six species were represented by one seedling or one sprout. Thirty‐eight percent of the seedlings were tree species, 59 percent were shrub species, and 2 percent were vines species. In contrast, 86 percent of the sprouts were from trees and 13 percent from shrubs. One year after the initial measurements, 29 percent of the seedlings and 13 percent of the sprouts were dead. Each of the seedling means (number of stems/individual, height and diameter of the tallest stem, and elliptical crown area) was significantly smaller (P < 0.05) than that of sprouts at all three measurement periods, but relative growth rates were similar. Total canopy area of seedlings had a larger relative increase than did the canopy area of sprouts. The presence of seedlings increased species diversity compared to calculated diversity excluding seedlings. Timing of fruit dispersal in relation to the date of burning and the high number of Leguminosae species in the forest appeared to favor seedling establishment for some species.

Efficacy and prognostic value of simple wound measurements.

To assess the association between planimetric wound area and simple wound measurements. To ascertain the applicability of planimetry-based research to clinical practice. A retrospective cohort study of 260 consecutive patients followed up for at least 24 weeks. Outpatient dermatology department of a major medical center. Wounds were measured using computer-based planimetry and were treated according to a standard protocol for venous leg ulcers. Two hundred sixty patients with venous leg ulcers. Complete ulcer healing at 24 weeks. Using the Pearson, Spearman, and Kendall correlation coefficients, we found a tight correlation between planimetric wound area and wound width, length, width x length, perimeter, and area based on the formula for an ellipse. The values for all correlation coefficients were greater than 0.80 (P < .001 for all associations). Width, length, length x width, and elliptical area measurements all correlated closely with failure to heal (P < .001). The correlation between simple values and planimetric area dropped considerably for wounds more than 40 cm2, which represented 6% of the wounds in this study. The equivalence between simple and planimetric wound measurements allows for the extrapolation of wound measurements from clinical trials to clinical practice, and suggests that simple wound measurements may confidently be used as predictors of healing in the clinical setting.

Modeling of heat conduction in elliptical cross section: II. Adaptation to thermal processing of shrimp

The quality of processed shrimp is partly determined by microbiological and textural attributes, and yield loss is economically important. Temperature is the most important variable that affects the above. A mathematical model was developed for the prediction of temperature distribution during cooking of shrimp. To develop the model, experimental cross-sectional areas of shrimp at different segments were compared with circular and elliptical cross-sectional area assumptions, and the circular cross-sectional area assumption was found to be a valid assumption for the model for its simplicity. The model used a finite difference approach with non-capacitance surface nodes (NCSN), and assumed variable thermal conductivity, specific heat, density, as well as changes in dimensions due to shrinkage. The mathematical model accurately predicted the temperature distribution in shrimp.

PORK SOFTNESS ASSESSED SUBJECTIVELY AND OBJECTIVELY USING VACUUM‐INDUCED CHANGES IN REFLECTANCE

ABSTRACTSubjective assessments were made of softness and paleness in longissimus muscles of 382 sides of pork. Softness was correlated with paleness, (r = 0.57, P &lt; 0.001). Softness was tested objectively in another 48 pork loins by applying a vacuum (to −2 kPa) across an elliptical area of longissimus. Reflectance from the meat surface measured by fiber‐optics increased as the meat bulged outwards toward the vacuum. Pale pork was deformed to a greater extent than dark pork, and the initial slope of the reflectance‐pressure relationship was correlated with initial reflectance before deformation and with maximum reflectance during deformation. At the maximum extent of deformation, there was a decrease in reflectance if the meat touched the fiber‐optic light guide. By spectrophotometry of another 19 loins, the major difference between reflectance at 0 kPa and ≤−2 kPa was found at 470 nm.

The Pomici di Base plinian eruption of Somma-Vesuvius

The Pomici di Base eruption represents the first of a series of plinian eruptions which occurred at Somma-Vesuvius in the period 20,000 yr B.P.–79 A.D. These eruptions led to substantial demolition of the Mt. Somma stratovolcano and the formation of the 4.9×3.4 km E–W-elongated summit caldera. New 14 C datings and previous radiometric data constrain the age of the Pomici di Base eruption to between 18,000 and 19,000 yr B.P. Deposits of the Pomici di Base eruption comprise from base to top: (1) plinian fallout with minor surge deposits and (2) a succession of volcanic landslide and lithic-rich fallout, surge and flow deposits. Ballistic block distribution and thickness of tephra deposits indicate that the vent was located in a 50° wide western sector within a distance of 1–2.5 km from the present Vesuvius crater, in a fairly eccentric position with respect to the ancestral Somma cone. The plinian fallout likely blanketed an eastwards elliptical area of 2600 km 2 within the 20-cm isopach. Reconstruction of isopachs yields an approximate volume calculation of 4.4 km 3. Comparison of maximum thickness of the fallout deposit with other plinian deposits of Somma-Vesuvius suggests that the PB eruption was the largest explosive event of the volcano. The mass discharge rate deduced from clast dispersal models is estimated in the range of 2–2.5×10 7 kg/s, corresponding to a column height of 16–17 km. Part of the plinian phase was characterized by pulsatory behaviour with repeated partial column collapses (surge emplacement) and concurrent oscillation of the height of the plume (stratified fallout). The plinian phase was followed by a limited slope failure of the Somma cone and by several explosive episodes with a prominent phreatomagmatic nature. We proposed that this activity occurred in connection with a phase of substantial demolition of the Somma edifice due to caldera collapse. The plinian fallout is dominated by strong compositional zoning from white trachytic pumice (SiO 2 63.0 wt.%) to black latitic scoriae (SiO 2 53.7 wt.%), coupled with a marked decrease of vesicularity of juvenile clasts from 70–80% to 45–55%. The compositional variation reflects strong pre-eruptive zoning of the magma chamber probably associated with volatile zonation.

Stress singularity near the crack-tip in silicon carbide: investigation by atomic force microscopy

A new technique using the high spatial resolution of atomic force microscopy (AFM) was developed to measure the near-tip stress field. In order to assess the sensitivity of the proposed technique, the near-tip stress singularity at a 98 N Knoop crack in hot-pressed silicon carbide was investigated by in situ AFM observations during bending with a stress of 110 MPa. The topographies obtained in the AFM observations indicated that the near-tip stress singularity produced an elliptical hollow area with a long axis of ∼20 μm. The vertical displacement was highest near the crack-tip with a maximum of 2.5 nm. Three-dimensional finite-element (FEM) analyses were performed and the displacements obtained were consistent with those measured by AFM. It was verified that the crack-tip stress field can be evaluated by analyzing the AFM topographies and that the depression measured by AFM originates in the stress singularity.

Elliptical boundary of an intraplate volcanic field, Auckland, New Zealand

The outer vents in the Auckland Volcanic Field lie within 19 to 559 m (mean 224.75 m) of a `best-fit' ellipse with a 28.9-km-long major axis trending almost north–south, and a minor axis 16.5 km long. The ellipse has formed the outer boundary of the field since the inception of volcanism 140,000 years ago. We present the following testable hypotheses as an explanation of this pattern: The boundary is the expression of a corresponding elliptical source area at depth in the lithospheric mantle (possibly asthenosphere material trapped at this level). The ellipse may represent a depth contour on a very small upper mantle dome or of a lens intruding into a neck of an extensional structure. Alternatively it could be the boundary of a flat elliptical area where tensional stresses allow decompressional melting. The elliptical tensional region may either have developed in a releasing bend during strike-slip faulting along a fundamental lithosphere structure inherited from Mesozoic tectonics, associated with the NNW-trending Dun Mountain ophiolite belt, or may represent the tip of a fracture along which the Auckland Volcanic Province is propagating northward.

Lateral contact of slender prismatic bodies

Many nominally two‐dimensional contact problems, such as the contact of parallel rollers or spur gears, exhibit slow axial variation in contact conditions due to manufacturing errors, misalignment or generalized beam deflections of the contacting bodies. In this paper, an asymptotic method is used to develop a solution to such problems, the inner problem being the two‐dimensional Hertzian contact theory and the outer problem the bending of the contacting bodies as beams separated by a nonlinear elastic foundation. The method is illustrated in the case of two cylindrical rollers that are slightly misaligned and pressed together by forces applied at their ends. The classical Hertzian elliptical contact area is obtained at low loads, but with increasing load the contact area evolves first into a dog‐bone shape and then into two separated contact areas surrounding the point forces that would be predicted by an elementary beam theory solution of the problem.

Miocene rhyolitic welded tuff infilling a funnel-shaped eruption conduit Shiotani, southeast of Matsue, SW Japan

At Shiotani, SW Japan, rhyolitic welded tuff forms a steep-sided funnel-shaped body, confined by Paleogene granitic rocks to an elliptical area 1–1.5 km across. The Shiotani welded tuff is pervasively welded and foliated concordantly with the contact that dips inward at angles of 70–90°. In contrast, nearby contemporary volcaniclastic deposits are non-welded and gently inclined. Near the contact with the granite, the tuff is plastically deformed and shows lineations that plunge inward at angles of 40–65°. Lithic and crystal clasts in the rheomorphic outer part are rotated in a plane normal to the foliations and parallel to the lineations indicating downward flow of the welded tuff. The geometry and internal structures suggest that the Shiotani welded tuff was emplaced and welded in a funnel-shaped eruption conduit. Upon collapse of a plinian or phreatoplinian eruption column, the majority of the conduit-filling pyroclasts probably fell back en masse into the conduit. Heat and steam from underlying magma and diffusion of interstitial volatiles into the glass perhaps reduced the viscosity of juvenile pyroclasts and facilitated welding in the conduit, especially at deep levels. The hot welded pyroclasts then flowed down the conduit wall during welding compaction and retreat of the magma. These processes resulted in increased welding toward the contacts and welding foliations concordant with the steep wall. Emplacement of nearby correlative volcaniclastic mass-flow deposits in a shelf to upper bathyal environment suggests a possibility that, when active, the Shiotani conduit was under the sea. Welding compaction would occur even under the sea provided that the steam generated in the upper part of the conduit fill prevented water access.