Morphological ontogeny of Protoribates dentatus (Acari, Oribatida, Haplozetidae)

2018 ◽  
Vol 23 (4) ◽  
pp. 613
Author(s):  
Stanisław Seniczak ◽  
Anna Seniczak ◽  
Sławomir Kaczmarek ◽  
Tomasz Marquardt
Keyword(s):  
Cross Section ◽  
Anal Opening ◽  
Posterior Position

The morphological ontogeny of Protoribates dentatus (Berlese, 1883) is described and illustrated. The juveniles of P. dentatus are elongated, oval in cross section, and their prodorsal, gastronotal setae and most setae on the legs are thin, smooth or with short barbs, which is typical of xylophages. Typical for this group is also a posterior position of the anal opening and relatively thick leg segments and claws, especially on leg I. The larva of P. dentatus has 11 pairs of gastronotal setae, including h2;and setae c2, la and lm are with excentrosclerites. The nymphs have 15 pairs of setae, of which c2, l- and h-series are with excentrosclerites. The adult of this species has a long seta ad1 (which is short in most congeners) and the number of claws varies on all leg tarsi.

Morphological ontogeny and ecology of Adoristes ovatus (Acari: Oribatida: Liacaridae), with comments on Adoristes Hull

2017 ◽  
Vol 22 (12) ◽  
pp. 2038 ◽  
Author(s):  
Anna Seniczak ◽  
Stanisław Seniczak ◽  
Sławomir Kaczmarek ◽  
Bogusław Chachaj
Keyword(s):  
Sex Ratio ◽  
Cross Section ◽  
Body Length ◽  
Junior Synonym ◽  
Thin Line ◽  
Anal Opening ◽  
The Mean ◽  
Gravid Females

The morphological ontogeny of Adoristes ovatus (C.L. Koch, 1839) is described and illustrated. The adult has the interlamellar seta shorter than the lamella and the translamella is usually absent, but can also be incomplete, or present as a thin line. The juveniles are unpigmented, oval in cross-section, with thin and smooth prodorsal and gastronotal setae, and with the anal opening in the posteroventral position, which is typical of xylophages. The legs and claws of juveniles are relatively thick, especially leg I, and the leg setae are smooth or with short barbs. All juveniles have a sclerotized semicircle located anterior to each prodorsal seta le. The larva has 11 pairs of gastronotal setae, the nymphs have 12 pairs, without the d-series. The mean body length of females is larger than males, but varies greatly among samples (445–735 μm) and the largest females can be 1.5 times longer than the smallest males. The sex ratio and the number of gravid females also vary among samples. We provisionally consider Adoristes (Gordeeviella) Shtanchaeva, Subías & Arillo, 2010 a junior synonym of Adoristes Hull, 1916.

How to Correct Increased Anteversion of the Femoral Neck during THR

1996 ◽  
Vol 6 (4) ◽  
pp. 135-139 ◽  
Author(s):  
E. Morscher
Keyword(s):  
Femoral Neck ◽  
Cross Section ◽  
Femoral Stem ◽  
Great Majority ◽  
Normal Range ◽  
Anteversion Angle ◽  
Derotational Osteotomy ◽  
Custom Made ◽  
Cemented Stem ◽  
Posterior Position

In the great majority of the cases the “Anteversion Angle” (AVA) is in the normal range (10-20°) and on insertion the femoral stem follows automatically the direction of the femoral neck. There are basically 5 means of correcting an increased AVA: 1) The smaller the diameter of the endoprosthetic stem and the more its cross-section is circular the easier it is to modify the rotational position. 2) The lower the resection of the femoral neck the greater the freedom of correction of the anteversion. 3) A custom-made femoral endoprosthesis. 4) A non-cemented endoprosthesis with a stem circular in cross section - such as the conical stem of Wagner - can easily be positioned in a great variety of rotational positions. 5) To correct an AVA of the femur of more than 45 degrees an inter- or sub-trochanteric derotational osteotomy of the femur is indicated. With this not only is the AVA corrected but also the greater trochanter is brought from its posterior position to a more lateral one and the functional lever arm of the abductors is lengthened. To stabilize the osteotomy the use of a femoral endo-prosthesis with a non-cemented stem which is stable in rotation all along its length is recommended.

XUV Absorption Spectra of Carbon Ions

1988 ◽  
Vol 102 ◽  
pp. 71-73
Author(s):  
E. Jannitti ◽  
P. Nicolosi ◽  
G. Tondello
Keyword(s):  
Absorption Spectra ◽  
Cross Section ◽  
Theoretical Calculations ◽  
Photoionization Cross Section ◽  
Carbon Ions

AbstractThe photoabsorption spectra of the carbon ions have been obtained by using two laser-produced plasmas. The photoionization cross-section of the CV has been absolutely measured and the value at threshold, σ=(4.7±0.5) × 10−19cm2, as well as its behaviour at higher energies agrees quite well with the theoretical calculations.

Elastic Scattering in Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 252-253
Author(s):  
J. Langmore ◽  
M. Isaacson ◽  
J. Wall ◽  
A. V. Crewe
Keyword(s):  
Electron Microscopy ◽  
Elastic Scattering ◽  
Cross Section ◽  
Quantum Noise ◽  
Dark Field ◽  
Elastic Cross Section ◽  
Biological Molecules ◽  
Dark Field Microscopy ◽  
Field Systems ◽  
Effects Of Radiation

High resolution dark field microscopy is becoming an important tool for the investigation of unstained and specifically stained biological molecules. Of primary consideration to the microscopist is the interpretation of image Intensities and the effects of radiation damage to the specimen. Ignoring inelastic scattering, the image intensity is directly related to the collected elastic scattering cross section, σɳ, which is the product of the total elastic cross section, σ and the eficiency of the microscope system at imaging these electrons, η. The number of potentially bond damaging events resulting from the beam exposure required to reduce the effect of quantum noise in the image to a given level is proportional to 1/η. We wish to compare η in three dark field systems.

A New Approach to the Demonstration of Oxidase-Localization Using Tannic Acid Or Catechin

1973 ◽  
Vol 31 ◽  
pp. 698-699
Author(s):  
V. Mizuhira ◽  
Y. Futaesaku
Keyword(s):  
Cross Section ◽  
Tannic Acid ◽  
Elastic Fiber ◽  
The Other ◽  
New Approach ◽  
Tissue Block ◽  
Active Reaction ◽  
The Cross

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.

Electron Irradiation Effects in Polyoxymethylene Crystals Grown Inside Trioxane Crystals

1971 ◽  
Vol 29 ◽  
pp. 78-79
Author(s):  
J. P. Colson ◽  
D. H. Reneker
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Detailed Examination ◽  
The Other ◽  
Electron Micrograph ◽  
Irradiation Effects ◽  
Threefold Axis ◽  
Typical Sample ◽  
Polymer Crystals ◽  
Chain Axis

Polyoxymethylene (POM) crystals grow inside trioxane crystals which have been irradiated and heated to a temperature slightly below their melting point. Figure 1 shows a low magnification electron micrograph of a group of such POM crystals. Detailed examination at higher magnification showed that three distinct types of POM crystals grew in a typical sample. The three types of POM crystals were distinguished by the direction that the polymer chain axis in each crystal made with respect to the threefold axis of the trioxane crystal. These polyoxymethylene crystals were described previously.At low magnifications the three types of polymer crystals appeared as slender rods. One type had a hexagonal cross section and the other two types had rectangular cross sections, that is, they were ribbonlike.

Freeze-Fracture Replication of Frozen Outer Segments of Rat Retinal Rods

1969 ◽  
Vol 27 ◽  
pp. 392-393
Author(s):  
Thomas S. Leeson ◽  
C. Roland Leeson
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Outer Segment ◽  
Freeze Fracture ◽  
X Ray Diffraction ◽  
X Ray ◽  
Outer Segments ◽  
Retinal Rods ◽  
Temperature Electron ◽  
Freeze Etching

Numerous previous studies of outer segments of retinal receptors have demonstrated a complex internal structure of a series of transversely orientated membranous lamellae, discs, or saccules. In cones, these lamellae probably are invaginations of the covering plasma membrane. In rods, however, they appear to be isolated and separate discs although some authors report interconnections and some continuities with the surface near the base of the outer segment, i.e. toward the inner segment. In some species, variations have been reported, such as longitudinally orientated lamellae and lamellar whorls. In cross section, the discs or saccules show one or more incisures. The saccules probably contain photolabile pigment, with resulting potentials after dipole formation during bleaching of pigment. Continuity between the lamina of rod saccules and extracellular space may be necessary for the detection of dipoles, although such continuity usually is not found by electron microscopy. Particles on the membranes have been found by low angle X-ray diffraction, by low temperature electron microscopy and by freeze-etching techniques.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Oxygen K near edge structures studied with multiple scattering calculations

1988 ◽  
Vol 46 ◽  
pp. 504-505
Author(s):  
Xudong Weng ◽  
Peter Rez
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Partial Cross Section ◽  
Energy Window ◽  
Edge Structure ◽  
Fine Structures ◽  
Hydrogenic Model ◽  
Electron Energy Loss ◽  
Quantitative Chemical

In electron energy loss spectroscopy, quantitative chemical microanalysis is performed by comparison of the intensity under a specific inner shell edge with the corresponding partial cross section. There are two commonly used models for calculations of atomic partial cross sections, the hydrogenic model and the Hartree-Slater model. Partial cross sections could also be measured from standards of known compositions. These partial cross sections are complicated by variations in the edge shapes, such as the near edge structure (ELNES) and extended fine structures (ELEXFS). The role of these solid state effects in the partial cross sections, and the transferability of the partial cross sections from material to material, has yet to be fully explored. In this work, we consider the oxygen K edge in several oxides as oxygen is present in many materials. Since the energy window of interest is in the range of 20-100 eV, we limit ourselves to the near edge structures.

Mass Determination by Direct Measurement of Electron Scattering

1975 ◽  
Vol 33 ◽  
pp. 240-241
Author(s):  
M. K. Lamvik ◽  
A. V. Crewe
Keyword(s):  
Cross Section ◽  
Electron Scattering ◽  
Mass Density ◽  
Variable Mass ◽  
Scattering Cross Section ◽  
Mass Determination ◽  
Number Density ◽  
Cross Sectional ◽  
Thin Slice ◽  
Scattering Cross

If a molecule or atom of material has molecular weight A, the number density of such units is given by n=Nρ/A, where N is Avogadro's number and ρ is the mass density of the material. The amount of scattering from each unit can be written by assigning an imaginary cross-sectional area σ to each unit. If the current I0 is incident on a thin slice of material of thickness z and the current I remains unscattered, then the scattering cross-section σ is defined by I=IOnσz. For a specimen that is not thin, the definition must be applied to each imaginary thin slice and the result I/I0 =exp(-nσz) is obtained by integrating over the whole thickness. It is useful to separate the variable mass-thickness w=ρz from the other factors to yield I/I0 =exp(-sw), where s=Nσ/A is the scattering cross-section per unit mass.

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