Dense Rows Research Articles

The Spectrum of Diffuse and Focal Liver Lesions in Workers Exposed to Vinylchloridemonomer

The Spectrum of Diffuse and Focal Liver Lesions in Workers Exposed to Vinylchloridemonomer

Microscopic segregation in intergrowth layers of (Hg, Re)Ba 2Ca n−1 Cu nO y

Microscopic structures of (Hg, Re)Ba 2Ca n−1 Cu n O y (nominally n = 4) have been investigated by means of high-resolution electron microscopy. Remarkable structural changes were detected during the observations. The lattice images viewed along the a-axis showed an ordinary intergrowth of members with mostly n > 4 in the matrix of the n = 4 host lattice. On heating crystals by a weak electron beam, dense rows of nm size domains accompanied by large strain fields appeared selectively at the intergrowth layers. However, further heating by an intense electron beam wiped off these domains, and strain-free lattices were recovered. These successive changes in the microstructure are interpreted in terms of the two-dimensional disproportionation of Re content on the Hg sites. It is suggested that the observed small domains with a typical size of 3 nm parallel to a 10 nm normal to intergrowth layers may provide promising pinning centers for flux lines in the mixed state.

A New Species of Paspalum (Gramineae) from Bolivia

Summary. A new species, Paspalum reticulinerve Renvoize, is described from Bolivia and compared with 6 other related species of section Pectinata Chase ex Rodriguez. The genus Paspalum with 330 species, the majority of them in the New World, is the fourth largest in the Gramineae, after Poa (500), Panicum (470) and Festuca (450). Paspalum species are readily recognized by their typically ovate, orbicular or elliptic, strongly plano-convex 2-flowered spikelets arranged in 2 or 4 dense rows on one side of a broad or narrow rachis. The new species described here is somewhat atypical and belongs to Section Pectinata Chase ex Rodriquez in which the spikelets are strongly dorsiventrally flattened, imbricate, and lanceolate in shape, and the upper glume is usually winged and cordate. The new species differs from all the other related species most obviously in its ciliate rachis. P. reticulinerve Renvoize sp. nov. P. aspidioti Trin. affinis sed planta omnis villosa, laminis angustioribus, racemis exsertis, rachidi ciliata, spiculis brevioribus differt. Typus: Bolivia, Solomon 17003 (holotypus LPB; isotypi K, MO). Gramen perenne, caespitosum, villosum; culmis erectis 120 cm altis. Foliorum basalium vaginae papyraceae; laminae lineares 20-30 cm x 3-5 mm planae attenuatae, basi rectae. Racemi 2(-3) terminales exserti conjugati 9 cm longi; rhaches lunares, 1 mm latae, ciliatae. Spiculae solitariae late lanceolatae, 4 -55 mm longae, dorsiventraliter compressae bifariae imbricatae. Gluma superna lemmatem infera longior et latior, foliaceo-alata, alae reticulato-venosae acutae cordatae 5-nerviae, margines apicalibus ciliolati. Lemma infera coriacea granulatopapillosa, 3 -5 mm longa, alata, alis reticulato-venosis, basi plicatis marginibus apicalibus ciliolatis. Anthoecium hermaphroditum ellipticum 3 mm longum. Caespitose, villous perennial with erect culms 120 cm high. Basal leaf-sheaths papery; blades linear, 20-30 cm x 3-5 mm, straight at the base, flat, tapering at the apex. Racemes 2(-3), exserted, conjugate, 9 cm long; rachis crescentic, 1 mm wide, ciliate. Spikelets usually solitary, occasionally paired imbricate, arranged in two rows, broadly lanceolate, 4"-5-5 mm long, dorsi-ventrally compressed. Upper glume longer and broader than the lower lemma, foliaceously winged, the wings reticulately nerved, cordate, 5-nerved, acute, the margins ciliolate near the apex. Lower lemma coriaceous, granular-papillose, 3-5 mm long, winged, the wings reticulately nerved, plicate at the base, the margins ciliolate towards the apex. Upper floret hermaphrodite, elliptic, 3 mm long. Fig. 1A-G.

Detailed analysis of the voltammetry of Rh(111) in perchloric acid solution

The preparation and surface treatment of a rhodium single crystal with (111) orientation are described. Surface characterization by scanning tunnelling microscopy (STM) in air, including topography and atomic-scale pictures, is reported. Hexagonal surface domains one atomic diameter thick are observed with edges parallel to the dense rows of the basal orientation; three or four atomic levels are included in this distribution. The atomic resolution reveals a surface lattice with the 2 x 2 periodicity, probably formed by oxygen adatoms. The voltammetric electrochemical study was carried out using perchloric acid solution which is known to give a reduction of the perchlorate anion at an Rh electrode. The reduction of perchlorate is revealed at low sweep rates. The effect of the formation of chloride anions or other anionic reduction products on the voltammetric response of this electrode was investigated in detail. A dramatic effect was found regarding the unusual reversible adsorption state around 0.6 V, which is very often compared with the unusual adsorption state of Pt(111) in the same solution. A quantitative analysis of the various adsorption states is given. The unusual state is shown to be sensitive to the electrochemical oxidation of the surface above a potential threshold of 1.080 V (RHE), similar to the behaviour of Pt(111). The presence of this state is thus shown to be characteristic of two-dimensional long-range order.

Globally convergent parallel algorithms for solving block bordered systems of nonlinear equations

Block bordered systems of nonlinear equations are systems whose Jacobian matrix consists of a series of diagonal blocks, plus a border of possibly dense rows and columns. Large systems of this type occur in many applications in science and engineering, and are attractive candidates for solution on parallel computers. Recently, Zhang, Byrd, and Schnabel developed a new class of algorithms for solving such systems that has significant computational advantages over previous methods on sequential computers, and even greater advantages on parallel computers. Its main feature is that the methods perform multiple inner iterations on the diagonal blocks for each outer iteration on the overall system, in a new way that retains fast local convergence. This paper investigates whether one can develop related algorithms that retain these advantages of parallelizability and fast local convergence, and are also globally convergent and computationally robust on a broad class of problems, including those where the Jacolbian matrix or any diagonal block is singular or ill-conditioned. We introduce related new algorithms for solving such systems, and show that they have strong global convergence properties under very mild assumptions, and retain parallelizability and fast local convergence.

LU decomposition of matrices with augmented dense constraints

AbstractSparse matrices composed of a central band and augmented dense rows and columns are becoming prevalent in the numerical solution of a large class of boundary and initial‐value problems. A Fortran Subroutine ARROW is presented for the LU decomposition and solution of linear equation systems with such a structure. The computational speed of the program is compared in MFLOPS (millions of floating point operations per second) to the LINPACK benchmark for the solution of a dense linear system and is found to be of comparable speed on both supercomputers and minicomputers. Use of the Basic Linear Algebra Subroutines (BLAS) available on most machines significantly enhances the speed of ARROW.

Homogeneity qualification of GaAs substrates for large scale integration applications

A novel procedure is used to qualify the homogeneity of GaAs substrates for large scale integration (LSI) circuit applications. This procedure is particularly well adapted for assessing the electrical variations of densely packed field-effect transistors (FET’s) used in GaAs LSI circuits. Threshold voltage nonuniformity due to crystal inhomogeneity and surface effects is measured for both conventional and In-alloyed, dislocation-free, slightly Cr-doped, semi-insulating liquid encapsulated Czochralski substrates. The average value of the threshold voltage standard deviation of about 300 dense rows over a 2-in.-diam wafer (30 FET’s over 300 μm for each row) is 20 mV using dislocation-free substrates which is much smaller than in conventional substrates (50–100 mV). These data show the importance of this qualification test with the highest ever reported resolution of 10 μm suitable for the evaluation of fabrication yield of LSI circuits.

Studies on Management of the Sunflower Leafcutter BeeEumegachile Pugnata(Say) (Hymenoptera: Megachilidae)

SummaryA previous study indicated that Eumegachile pugnata may be managed for pollination of sunflower. Additional field studies show that females prefer to nest in deep holes along the margins of nesting units (wooden blocks with holes containing drinking straws). More nests were made in units placed in dense rows of unthinned sunflower plants than were made in units placed at the field margin. An 8-fold increase in the field population was obtained in hybrid plantings and less than 1% of the bee cells were destroyed by nest associates. Mortality of immature stages differed within nesting units; egg mortality in nests constructed near edges exposed to long periods of sunlight was higher than in nests made in protected areas of the unit.

Larval and Early Juvenile Development of the Frillfin Goby, Bathygobius soporator (Perciformes: Gobiidae)

Larval and early juvenile development of laboratory-reared frillfin gobies, Bathygobius soporator (Cuvier and Valenciennes, 1837), is described and figured. One-day-old preserved specimens averaged 2.0 mm SL, had 11-12 preanal myomeres, and 25-26 total myomeres. Caudal fin rays appeared at 3.1 mm SL (10 days), followed by soft dorsal and anal fin rays at 3.4 mm SL (11 days). Dominant larval pigmentation consisted of dense rows of stellate melanophores along the dorsal and anal midlines and later along the lateral midline. The change to juvenile pigmentation and a benthic habit occurred at 4.7-5.4 mm SL (26-31 days). Early juvenile growth was characterized by migration of the eyes to the adult position, rounding of the caudal fin margin, beginning of scale formation, and separation of the upper pectoral fin rays.

Prismatic cristae and paracrystalline inclusions in mitochondria of myocardial cells of the oyster Crassostrea virginica Gmelin.

Several types of unusual mitochondrial configurations were found in myocardial cells of the oyster Crassostrea virginica Gmelin. These mitochondria include, in order of frequency, prismatic cristae, filamentous paracrystals in honeycomb and herringbone configurations, and paracrystals composed of rows of electron dense particles. The long, parallel, evenly spaced prismatic cristae are square or rhomboidal in cross section. In the space between the prismatic cristae are rodlike structures (4--6 nm in diameter) that are regularly spaced about 12 nm apart and appear to pass between adjacent cristae. Filamentous paracrystals observed in slender, elongated mitochondria. The filament spacing and form of these paracrystals suggest that they are composed of the intercristal rods. Alternatively, filamentous paracrystals might be tangential sections of prismatic cristae and intercristal rods. Particulate paracrystals which consist of dense lines or rows of particles are the least frequent type of unusual configuration. The particles are triangular, possibly pyramidal, in shape; their bases are 10-12 nm thick and repeat in rows every 17-18 nm. There is a close association between particulate paracrystals and prismatic cristae plus intercristal rods. Although similar mitochondrial configurations have been associated with disease or altered metabolism in a number of species, we have found so such association in the oyster as yet.

Adsorption and desorption of lead on low-index and stepped copper surfaces

Results from LEED, AES and isothermal desorption experiments are reported for monolayers of lead on low-index and stepped copper surfaces. Data for the (100), (711), (511), (311), (211) and (111) substrate orientations are discussed. Plots were made of the Auger peak-to-peak heights as a function of time during adsorption. These plots show breaks corresponding to the formation of dense monolayers and also earlier breaks due to changes in the sticking probability at the completion of submonolayer structures. The breaks permit a calibration of the spectrometer. For all substrate orientations LEED patterns were obtained with four-fold coincidence periodicities which are interpreted in terms of dense rows of lead atoms. For the stepped surfaces these rows are always parallel to the step directions. The desorption data (peak-to-peak heights as a function of time) show zero-order kinetics with initially a fast reaction and then a slow reaction that sets in at a coverage that depends on the orientation. The dominance of the fast reaction for (111) is related to the subsistence of islands of the compact monolayer arrangement down to low coverages.

Electrocrystallization of various metals onto copper single crystal substrates

Nickel, lead, zinc and cadmium were electrodeposited onto single crystal planes (111), (001) and (110) of copper in order to study the nucleation, crystal growth and epitaxy involved. Morphological aspects were quite characteristic of the deposited metals and of the orientation of the copper substrates. Thus, typical deposits were densely packed tiny crystallites giving rise to a rather flat deposition layer in nickel deposition, well-developed isolated crystals in lead or cadmium deposition, and stacking layers or ridges in zinc deposition. It was realised that such differences in nucleation and growth manner between depositing metals are explicable in terms of exchange current density and surface diffusion. As for epitaxial relations, it turned out that the observed results could not be reasonably accounted for in terms of misfit only. It is proposed, with a supporting discussion, that the directional coincidence of the most dense atom rows between deposit and substrate is more important in determining epitaxy.

Multiple diffraction origin of low-energy electron diffraction intensities

The angular and voltage dependence of the diffracted intensity for electrons in the energy range of 150–900 volts from a clean tungsten (110) surface has been measured with a single-crystal diffractometer. Selecting the angle of incidence and the electron wavelength to satisfy the Bragg condition the crystal is rotated about its normal, and a Renninger plot of diffracted intensity versus azimuthal angle is made. Strong intensity variations are observed when the plane of diffraction is parallel to those low index crystallographic planes which contain relatively dense atomic rows. Additional structure occurs for each intersection of an extended reciprocal lattice point with the Ewald sphere. For some orientations the intensity is reduced to half the value within one degree, which is the beam divergence. When simultaneous diffraction does not occur, the intensities of the Bragg maxima are close to the background. The integral order Bragg maxima observed in electron diffraction are thus shown to have their origin in multiple diffraction. The frequently observed fractional order Bragg maxima are predicted to have the same origin. Renninger plots for such maxima show this to be the case. In addition the appearance of the fractional order peaks should depend only on the geometry for multiple diffraction. Intensity versus voltage curves for the beam incident along the [hkl] direction are predicted to have maxima of order (h2 + k2 + l2)−1, which is verified. The implication of these observations in terms of previous two-beam models is discussed.

The Proventricular Armature of Curculionidae (Coleoptera)1

Curculionid weevils have three types of proventricular armature. The simplest type occurs in primitive groups of weevils with straight antennae, and is characterized by eight longitudinal, unsclerotized folds randomly covered with discrete setae. The majority of curculionids have eight sclerotized plates, each bearing two dense rows of setae in longitudinal arrangement. Ophryastini, Thecesterninae, and Gonipterinae also have eight sclerotized plates, but each plate bears a large, toothlike process. Representatives of 54 subfamilies were studied.

Snowdrifts as a Factor in Growth and Longevity of Shelterbelts in the Great Plains

In 1934 and 1935 a survey was made of shelterbelts in the Great Plains (Hayes and Stoeckeler, '35) to determine which species had survived the recent drought years, and to study soil adaptability, longevity, and comparative effectiveness of belts of various composition and design. This survey revealed that, on lines of apparently equal effective rainfall, tree plantings in the northern plains had an average life span of about 20 years more than in the central or southern plains. This is explained partly on the basis of a longer growing season in the south and a more rapid exhaustion of the subsoil moisture. Another point of interest was the fact that tree plantings remained thrifty for a much longer time on deep sandy loam soils than on heavy soils such as clays or clay loams. This difference was much more striking in the southern than in the northern plains. Subsequent moisture samplings in the southern plains (Stoeckeler and Bates, '39) revealed a greater supply of available soil moisture in the sandy soils, and this was attributed to higher infiltration rate, relatively deep storage of water, and less evaporation loss. It was also observed that shelterbelts flanked by dense low-growing shrub rows retained their effectiveness longer than open poorly-stocked plantings, because the former more readily attain a dense crown canopy, shade out competing weeds and grass, and retain enough leaves to form a forest floor of litter and humus. It is a matter of common knowledge that dense plantings accumulate a considerable depth of snow in winter, and, since this might be a factor in the growth and longevity of tree belts, a study was made to determine to what extent snow replenished the soil moisture in and near shelterbelts.

The Ecological Problem of Mycotrophy

The idea of mutually beneficial symbiosis, offensive to so many biologists, seems superfluous as far as the orchid mycorhiza is concerned. Most of the orchid fungi thus far tested have been found to thrive when growing alone on leaf litter, wood, etc. (Hollknder, see Burgeff, '36). Several species have even formed fruiting bodies in pure culture on such substrates (Armillaria mellea, Mar-asmtius coniatus var., Xerotus javanicus). Such saprophytic fungi do not need the orchids, but the orchids need them either permanently (chlorophyll-free species) or at least for getting a start in life. The relation appears to be a parasitism 1 of the orchid on the fungus (Burgeff, p. 280). Different in principle is, according to accumulated evidence, the symbiotic relation between conifers and their mycorhizal fungi. Everyday experience in forestry shows that trees, in their food habits, are not parasitic on their mycorhizal fungi as some orchids appear to be. These fungi, on the other hand, behave much like parasites on the trees inasmuch as the fruiting bodies of many species are never found away from trees. Several such fungi are satellites of specific coniferous tree species (Romell, '21; Lange, '23). Cases are on record indicating that it is necessary for the mycorhizal fungus to have access to living and functioning roots of the host tree. In one place where Lactarius delicious grew earlier, it was never seen again after the winter when the few spruces in the stand were cut (Romell, '30). A most striking result was observed in a trenching experiment made by the writer in a spruce forest in Sweden, more fully described elsewhere. In the year following the trenching, fruiting bodies of a number of fungi (chanterelles, cortinarii, lactarii, Polyporus ovinus) were seen crowded around the trenched areas, forming in places dense rows along the outer side of the trench, but inside of the trenches they were totally absent (Romell, '38). The same picture was seen the next summer (fig. 1 ) . Mlelin ('25) found in his culture experiments with isolated mycorhizal

Effect of Indoleacetic Acid on Growth and Chemical Composition of Etiolated Bean Plants

1. Three per cent β-indoleacetic acid lanolin mixture applied to the first internode of etiolated bean seedlings caused the formation of galls at the point of application and the development of roots in the galls, and in many cases dense rows of roots developed the entire length of the hypocotyls. 2. The first internodes, second internodes, petioles, and leaves of treated plants increased less in volume, fresh weight, dry weight, and length than did corresponding parts of control plants. 3. The histological responses shown by treated regions of plants grown in continuous darkness closely resemble those shown by plants of comparable age grown under alternating light and darkness, as reported by other investigators. Histological differences between treated and untreated plants grown in continuous darkness were very great. 4. The application of indoleacetic acid to the first internode of etiolated plants retarded the transport of materials from the cotyledons and also the uptake of water by the plants. 5. Analyses of treated and untreated plants that included the determination of fresh weight, dry weight, volume, starch, sugar, and nitrogen contained in different portions of the plants showed that indoleacetic acid greatly affected the direction of transport of materials from the cotyledons. Materials were conducted from the cotyledons upward only as far as the first internode (the point of treatment) in the case of treated plants. At the end of the experiments, transverse sections through the treated portion of plants grown in the dark showed no apparent evidence of mechanical blockage or inhibition of development of the conductive tissues. 6. No significant differences were observed in the amount of dry matter respired by treated as compared with control plants.