Wide Cone Research Articles

Photoreceptor fine structure in the archerfish (Toxotes jaculatrix)

The fine structure and arrangement of the photoreceptor cells of the archerfish (Toxotes jaculatrix) have been studied by electron microscopy.Rods, twin cones, and single cones are present. In the light-adapted state, the rods are very tall cells reaching almost to the base of the retinal epithelial cells. The outer segment is composed of membranous discs of uniform diameter displaying a single incisure. The rod inner segment displays a distal small ellipsoid and an extremely thin myoid region. The nuclei of rods are electrondense,and the synaptic spherule displays two or three invaginated sites. The single cone is similar to the individual members of a twin cone and displays a tapering outer segment and accompanying accessory outer segment. The wider cone inner segment contains a large, centrally located ellipsoid and a peripheral region rich in endoplasmic reticulum, polysomes, and microfilaments.Twin cones display subsurface cisternae along their entire contiguous surfaces.The cone nuclei are large and vesicular and located vitread to the external limiting membrane. The synaptic pedicle of cones is larger and more electronlucent and contains more invaginated "ribbon" synaptic sites (ten to 12) than do rods. In addition, small "coated" invaginations and larger synaptic vesiclefilled processes are also seen within cone pedicles. In the light-adapted state the cone photoreceptors are arranged in a repeating square mosaic pattern with one single cone surrounded by four twin cones.

Galactic gas and the shapes of radio sources

view Abstract Citations (17) References (57) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Galactic gas and the shapes of radio sources Sparke, L. S. Abstract Large double-lobed extragalactic radio sources are associated with elliptical, rather than with spiral galaxies. In an earlier paper, it was suggested that the radio morphology of elliptical galaxies results from their slow rotation. Here, more precise calculations of the flow of a slowly spinning gas are presented, improving upon the order of magnitude estimates previously given. The energetic beam supplying a powerful radio source is likely to propagate freely away from the galaxy, but this, in a weaker source, may be disrupted quickly by interactions with the interstellar medium. In the latter case, the pressure of galactic gas will confine the radiating plasma to a narrow funnel along the rotation axis, producing a thin jet of emission. A similar beam in a spiral system is unlikely to escape through the dense interstellar matter; instead, radio-bright material may collect in wide centrifugally-induced cones in the galactic gas. This model predicts that the small double-lobed radio sources found within the forbidden line regions of Seyfert galaxies should point along the spin axis of the surrounding material. Publication: The Astrophysical Journal Pub Date: March 1982 DOI: 10.1086/159753 Bibcode: 1982ApJ...254..456S Keywords: Elliptical Galaxies; Extragalactic Radio Sources; Galactic Rotation; Galactic Structure; Gas Flow; Interstellar Gas; Seyfert Galaxies; Astronomical Models; Star Distribution; Stellar Winds; Astrophysics full text sources ADS |

A rotating wheel system for the detection of spontaneously fissioning nuclides from heavy ion reactions

A rotating wheel system for the detection of spontaneously fissioning reaction products from heavy ion reactions was developed. In this system products recoiling from a rotating target wheel are stopped in a catcher foil stack which can be rotated at various velocities up to 80 rotations per second. All products emitted within a wide emission cone are stopped in the catcher foils and are rotated into shielded positions with stationary fission-track detectors positioned on both sides of each rotating foil. This technique allows a sensitive detection of spontaneously fissioning nuclides over a broad range of half-lives from 1 ms to about 1 d. By post-bombardment exposure of the catchers to new fission-track detectors, the half-lives covered can be extended to about 1 y. From their range and angular distributions within the catcher foils, heavy-ion fusion products can be distinguished from nuclides produced in damped collisions, and excitation functions can be extracted.

A radiation model for the vela pulsar

We model the Vela emission in radio, optical and gamma wavelengths. We assume that radio emission occurs near the polar axis deep in the magnetosphere. Optical and gamma radiation arises through ordinary synchrotron mechanisms in a wide hollow cone, near the light cylinder. Fitting of observed frequencies and luminosities in the gamma and optical give reasonable plasma parameters, and indicate that field-plasma pressure balance breaks down before the light cylinder, as required by the picture. Some optical coherence is necessary if we attribute both radio and optical emission to the same species of particles, with γ∼100, but it is not required otherwise. Gamma-ray pulses arise from γ∼105 electrons. We suggest a single-pole orthogonal rotor picture which might account for the Vela pulse phases.

Local effective emissivity of conical cavities

The local effective emissivity for a point on the interior surface of a diffusely reflecting blackbody cone obeys an integral equation. A new analytic approximate solution of the integral equation is presented. This approximation is very good for interior portions of narrow cones where the effective emissivity is very close to unity. Another approximation of Kelley is better near the mouth of a narrow cone. Either approximation works for wide angle cones. The new approximation is modified to give a quantitative estimate of the effects of a temperature gradient along the side of the cone.

Multislice Reconstruction from Twin-Cone Beam Scanning

A twin-cone scanning geometry and a reconstruction method are proposed capable of multislice-reconstructing using wide cone angles.

The adsorption of cycloparaffins on Ru(001) as studied by temperature programmed desorption and electron stimulated desorption

The adsorption of C 2H 6, and the cycloparaffins C 3H 6, C 6H 12, and C 8H 16 on Ru(001) at 80 K has been studied using LEED, temperature programmed desorption, and ESDIAD (Electron Stimulated Desorption Ion Angular Distributions). An aim of these studies has been to examine the relationship between ESDIAD ion desorption angles and bond angles in weakly adsorbed species having known internal structure. Fractional monolayers of C 2H 6 and C 3H 6 both yield ESDIAD patterns due to H + ions desorbed in wide cones centered on the surface normal, consistent with adsorption into mobile, disordered layers. In contrast, a fractional monolayer of C 6H 12 yields a hexagonal H + ESDIAD pattern. These results indicate the azimuthal orientation of the CH bonds and are consistent with a simple model of C 6H 12 adsorption. In thermal desorption studies, the weakly adsorbed layer in contact with the substrate is easily distinguished from condensed multilayers. Mass analysis of ESD ions reveals that the only ESD ion product is H + for hydrocarbon coverages <1 monolayer. For multilayers of adsorbed C 6H 12 and C 8H 16, the ESD ion products have a mass distribution similar to the gas phase mass spectrometer cracking pattern. For all these fragments, the ESD cross sections are ≳ × 10 −17 cm 2.

On the diurnal variation coefficients of the nucleonic component of cosmic rays

The expected amplitudes, as well as the time shift due to geomagnetic bending, of the diurnal waves have been calculated for 27 cosmic ray neutron monitors for the recent shapes of the diurnal, semidiurnal and tridiurnal anisotropies. The calculations are performed for latitude dependence of the form, cos n λ and rigidity dependence of the formR β exp [(1−R)/R 0] where λ is the asymptotic latitude,R is the rigidity in GV, andn, β andR 0 are constants. For the diurnal anisotropy, the calculations are given forn=1, β=−0.4, 0.0, +0.4, +0.8,R 0=∞ and maximum cutoff rigidity =90 GV, while for semidiurnal and tridiurnal anisotropies the results are given forn=1, 2, β=1, 2 andR 0=50, 90 GV. Moreover, the calculation of the attenuation due to the latitude effect, the smoothing effect, and the mean latitude and mean cone broadening are given for the different concerned anisotropies. The presently calculated coefficients for diurnal variation are significantly smaller than those calculated previously due to the careful selection of the used parameters. A considerable increase in the time shift due to geomagnetic bending is only found in the wide cone stations. The relation between the mean latitude, the cone broadening, the time shift, and the expected amplitude for all diurnal components and the minimum cutoff rigidity of the different stations are discussed.

Effect of trickle irrigation on soil‐applied herbicides*

Summary:The effect of trickle irrigation on the activity, leaching and distribution in the soil of herbicides, was studied in a model specially constructed for simulating trickle irrigation in the field, and also under field conditions.The pattern of movement of a soil‐applied herbicide in the soil under trickle irrigation paralleled, to some extent, that of the trickle water itself, but total herbicide movement was less than that of the water. Both water and herbicide distribution in the soil formed the shape of a hemisphere or cone under the trickle nozzle, the exact shape of which was determined by the soil characteristics (a narrow cone in a light soil and a wide cone in a heavy soil); cone size was determined by the amount of trickle water.Bioassays with susceptible test plants showed that effective weed control could be expected with either simazine or GS‐14259 (2‐t‐butylamino‐4‐ethylamino‐6‐methoxy‐s‐triazine =‘Caragard') only in the areas wetted by the trickle nozzle.The results showed that the pattern of distribution in the soil of simazine and GS‐14259 was similar, but there were quantitative differences in their final spread.

Measurement of charged particle multiplicities associated with large transverse momentum photons in proton-proton collisions

We have measured the behaviour or charged-particle multiplicities as a function of the transverse momentum of photons produced at 90° in proton-proton collisions. The data were obtained at the CERN Intersecting Storage Rings (ISR) at a centre-of-mass energy of 53 GeV and cover the transverse momentum range 0 < p ⊥ < 4.5 GeV/ c. The total associated charge multiplicity increases with p ⊥ and most of the increase is found in a very wide cone opposite the detected photons. Partial multiplicities in the direction of the photons vary only slightly with p ⊥. However, multiplicities at small angles with respect to the beams decrease sharply with increasing p ⊥.

Possible causes of woodwind tone colour

The reasons for the apparent differences between the tone qualities of woodwind instruments are not immediately apparent. This paper describes experiments aimed at isolating one variable, namely the bore shape, by using uniform brass cones of different apex angles. With the same reed being used to blow all the cones, there was a significant change in tone colour and harmonic spectra for the different cones. From the spectrum envelopes it was possible to measure the frequencies of the formants and relate them graphically to the cone dimensions; each cone produced a spectrum containing several formants which were found to be in a harmonic sequence. When these results are compared with others from several sources for the real wind instruments, they help to explain phenomena such as the marked change in tone colour across the ‘break’ between two registers. It is found that both the wide angled cones and instruments of similar conicality, e.g., the oboe, produce spectra having formants in the 1000 Hz region, and consequently, a more penetrating tone than the narrower cones and instruments. Apart from giving a ‘smoother’ tone, it was observed that these narrower cones could be excited in both quarter and half-wavelength modes, depending upon a critical adjustment of the generator. The evidence obtained from these experiments suggests that the formants are caused by the resonance frequencies of the reed, and are modified in frequency by the shape of the conical resonator.

Hematoporphyrin-derivative-fluorescence test colposcopy and colpophotography in the diagnosis of atypical metaplasia, dysplasia, and carcinoma in situ of the cervix uteri

The hematoporphyrin-derivative (Hp-D)-fluorescence test, based on the accumulation of Hp-D in cervical lesions in combination with colposcopy and colpophotography, has been evaluated for the detection and management of cervical atypism in 20 patients. All of them had guided punch biopsies of the cervix. Fourteen patients had wide cold-knife cone biopsies of the cervix. There were 3 cases of carcinoma in situ and 9 cases of moderate to severe dysplasia of the carvix with posïtive fluorescence. Positive fluorescence was seen in 2 additional cases of atypical squamous metaplasia. There were no false negative fluorescence tests in this group of patients. There was good correlation of the atypical colposcopic findings to the areas of subsequent fluorescence. The value of combining the Hp-D fiuorascence procedure and colposcopic-colpophotographic examination may be valudble for outlining the extent of minimal lesions of the cervix and vagina.

A New Cone Loud Speaker for High Fidelity Sound Reproduction

Economic conditions which are involved in every product designed for the multitudes have prevented the adoption of the various elaborate types of wide range sound reproducers. A consideration of this problem shows that the loud speaker is one of the component parts which has limited the range of radio and phonograph reproduction. This paper describes the result of a program of development on the production of a wide range cone loud speaker capable of delivering large acoustic outputs and at the same time retaining a system free from the complexities of construction usually associated with wide range electro-acoustic transducers. The wide range cone loud speaker consists of a voice coil and coil cylinder segregated into masses and compliances and connected to a cone suitably corrugated to present an impedance to the driving system which would yield uniform response from 80 to 10,000 cycles. Objective and subjective performance tests indicate that this loud speaker is suitable for high fidelity sound reproduction and substantiates the theoretical analysis.