The origin of the epidermis in the supernumerary regenerates of triple legs in cockroaches (Blattaria)1

Development ◽  
1972 ◽  
Vol 28 (1) ◽  
pp. 185-208
Author(s):  
Horst Bohn
Keyword(s):  
Cross Section ◽  
The Other ◽  
Entire Cross Section ◽  
Leucophaea Maderae ◽  
Gromphadorhina Portentosa ◽  
Anterior Posterior

An attempt has been made to clarify the origin of the supernumerary regenerates of triple legs by transplantations between two species of cockroaches, Gromphadorhina portentosa and Leucophaea maderae. The three ways of combining stump and transplant tissues were: heteropleural, dorso-dorsal, antero-posterior (I); heteropleural, dorso-ventral, antero-anterior (II); homopleural, dorso-ventral, antero-posterior (III). The transplantations have been performed at the level of the tibia as well as at the level of the coxa. (1) The supernumerary regenerates were partly mixed, i.e were composed of a mosaic of the tissues of both species of cockroach, partly homogeneously built up by the tissues of only one of the two species. In combination I nearly all regenerates were mixed; in the other two combinations homogeneous regenerates were relatively numerous, sometimes even the most numerous. Both supernumerary regenerates of a triple leg might be mixed; or one was homogeneous and the second mixed; or they were both homogeneous. In the latter case one regenerate was built up by Gromphadorhina tissues, the other by Leucophaea tissues, or, more rarely, both were built by up Gromphadorhina tissues. (2) The intraspecific transplantations simultaneously done in Leucophaea gave results which correspond in general with the results of the interspecific transplantations. (3) From the composition of the supernumerary regenerates it must be concluded that the four different properties of a cross-section (anterior, posterior, etc.) are not yet determined irreversibly in the tissues of the cockroach legs. Thus, missing properties may be completed by the other properties to give an entire cross-section.

scholarly journals Evaluating Different Methods for Determining the Velocity-Dip Position over the Entire Cross Section and at the Centerline of a Rectangular Open Channel

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 605
Author(s):  
Zhongfan Zhu ◽  
Pengfei Hei ◽  
Jie Dou ◽  
Dingzhi Peng
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Shannon Entropy ◽  
Open Channel ◽  
Lateral Distribution ◽  
Tsallis Entropy ◽  
The Other ◽  
Deterministic Models ◽  
Entire Cross Section ◽  
General Index

The velocity profile of an open channel is an important research topic in the context of open channel hydraulics; in particular, the velocity-dip position has drawn the attention of hydraulic scientists. In this study, analytical expressions for the velocity-dip position over the entire cross section and at the centerline of a rectangular open channel are derived by adopting probability methods based on the Tsallis and general index entropy theories. Two kinds of derived entropy-based expressions have the same mathematical form as a function of the lateral distance from the sidewall of the channel or of the aspect ratio of the channel. Furthermore, for the velocity-dip position over the entire cross section of the rectangular open channel, the derived expressions are compared with each other, as well as with two existing deterministic models and the existing Shannon entropy-based expression, using fifteen experimental datasets from the literature. An error analysis shows that the model of Yang et al. and the Tsallis entropy-based expression predict the lateral distribution of the velocity-dip position better than the other proposed models. For the velocity-dip position at the centerline of the rectangular open channel, six existing conventional models, the derived Tsallis and general index entropy-based expressions, and the existing Shannon entropy-based models are tested against twenty-one experimental datasets from the literature. The results show that the model of Kundu and the Shannon entropy-based expression have superior prediction accuracy with respect to experimental data compared with other models. With the exception of these models, the Tsallis entropy-based expression has the highest correlation coefficient value and the lowest root mean square error value for experimental data among the other models. This study indicates that the Tsallis entropy could be a good addition to existing deterministic models for predicting the lateral distribution of the velocity-dip position of rectangular open channel flow. This work also shows the potential of entropy-based expressions, the Shannon entropy and the Tsallis entropy in particular, to predict the velocity-dip position at the centerline of both narrow and wide rectangular open channels.

A comparative study of two experimental techniques for the measurement of residual stresses in circular rods and tubes of perspex

1989 ◽  
Vol 24 (3) ◽  
pp. 163-171
Author(s):  
R K Mittal ◽  
I A Khan
Keyword(s):  
Residual Stresses ◽  
Cross Section ◽  
The Other ◽  
Experimental Techniques ◽  
Entire Cross Section ◽  
Sum Rule ◽  
Thin Walled ◽  
Removal Technique ◽  
Non Destructive ◽  
Distribution Of Stresses

Two experimental techniques have been used to measure residual stresses in circular rods and tubes of perspex, i.e., polymethyl methacrylate (PMMA). The first technique, based on photoelasticity, is non-destructive and easy to apply. It gives distribution of stresses over the entire cross-section. The analysis of this technique has been improved to relax some restrictions. The other technique is the layer removal technique. A serious drawback of this technique is that it fails to give the distribution of stresses over the entire cross-section and its accuracy for thin walled tubes is doubtful. A simplification of this technique is possible if the kinematic assumption introduced by Nishimura is replaced by one using the sum rule of stresses.

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.

The Effect of Weld Length on the Tension Capacity of Hollow Structural Section (HSS)

2020 ◽  
pp. 42-58
Keyword(s):  
Cross Section ◽  
Uniform Stress ◽  
Entire Cross Section ◽  
Design Strength ◽  
Minimum Requirement ◽  
Tension Member ◽  
Hollow Structural Section ◽  
Hollow Structural Sections ◽  
Tension Capacity ◽  
Steel Standard

The non-uniform stress distribution occurs in a tension member adjacent to a connection, in which all elements of the cross-section are not directly connected. This effect reduces the member’s design strength because the entire cross-section is not fully effective in the critical section’s location. That's why an experimental study has been done to investigate the effect of the weld length on the tension capacity, two specimens (hollow structural sections) have been tested by using Instron 8800 machine with two weld lengths, 46 mm and 56 mm. The 46 mm size is the minimum requirement of the sufficient size of the tension connection depending on United States Steel Standard. The Result proved that there has been too much effect on the connection carrying tension capacity. The result of the 46 mm weld length is about 155 KN and about 180 KN for the 56 mm weld length. While the ABAQUS simulation results were about 168 KN for the 46 mm weld length and about 172 KN for the 56 mm weld length.

Effective, Shortened Drying of Agar-Gelcasting Al2O3 Tube Through Immersing in Acetone

2021 ◽  
Author(s):  
Ramnaree Kaemkit ◽  
Supawan Vichaphund ◽  
Anukorn Phureungrat ◽  
Methee Promsawat ◽  
Suksawat Sirijarukul ◽  
...  
Keyword(s):  
Cross Section ◽  
Concentration Gradient ◽  
Water Concentration ◽  
Drying Shrinkage ◽  
The Other ◽  
Air Drying ◽  
Al2o3 Tube ◽  
Acetone Water ◽  
Porous Microstructure ◽  
Glass Tubes

Abstract A liquid drying agent, i.e. acetone, was employed for allowing the faster drying of Al2O3 tubes fabricated by agar gelcasting than the conventional air drying. The mixture of Al2O3 slurry and agar solution was separately prepared and then mixed prior to molding out of a set of warmed glass tubes. After the mixture transformed into gelled tube, the gelled tube was demolded and then immersed in acetone at different periods of time from 0 to 50 h. The immersed periods of 50 h led to the acetone replacement for water being inside of the gelling tube by 74 wt.% and then shortened the drying period to be 25 min. On the other hand, the conventional air drying spent 420 min drying completely. After drying, the immersed tubes possessed spherical cross section; whereas, no immersed tubes showed the deformation of cross section. The shortened drying was in line with the smaller drying shrinkage (4.7%), broader pore-size distribution and higher porous microstructure, comparing to the conventional air drying. The mechanism of acetone replacement for water was attributed to the acetone-water concentration gradient creating their inter-diffusion.

The Defect Structure of BaTiO3 Thin Films

1993 ◽  
Vol 310 ◽  
Author(s):  
L.A. Wills ◽  
B.W. Wessels
Keyword(s):  
Thin Films ◽  
Cross Section ◽  
Defect Structure ◽  
Oxygen Vacancies ◽  
Vacuum Annealing ◽  
Deep Level ◽  
Energy Levels ◽  
The Other ◽  
Optical Cross Section ◽  
Impurity Defects

AbstractThe defect structure of BaTiO3 thin films grown on (100) Si was examined using transient photocapacitance spectroscopy. The concentration, optical cross section and associated energy levels of both native and impurity defects in as-grown and annealed BaTiO3 films were evaluated. Deep level defects withpeak energies of Ev+1.8, Ev+2.4, Ev+2.7, Ev+3.0-3.1 and Ev+3.2-3.3 eV were observed in the as-grown films. Upon vacuum annealing, the concentration of the traps at Ev+3.0 and Ev+3.2 eV increased while the concentration of the traps at Ev+ 1.8 and Ev+2.4 eV decreased. The levels at Ev+3.0-3.1 and Ev+3.2-3.3 eV are attributed to oxygen vacancies. The other levels are tentatively ascribed to Fe and Fe related defects.

scholarly journals I Like Vegetables: A Touch-and-Feel Board Book by L. Siminovich

2011 ◽  
Vol 1 (1) ◽  
Author(s):  
Kim Frail
Keyword(s):  
Cross Section ◽  
Public Services ◽  
Picture Book ◽  
The Other ◽  
Learning Method ◽  
University Of Alberta ◽  
Young Readers ◽  
Dinner Table ◽  
Wood Grain ◽  
The University

Siminovich, Lorena. I Like Vegetables: A Touch-and-Feel Board Book. Somerville: Candlewick Press, 2011. Print.“I Like Vegetables” is a dream come true for any nutritionally conscience parent, children’s librarian or teacher. The brightly hued collage illustrations are intriguingly textured with patterns and “touch & feel” inlays. Silky peas and rough-skinned carrots invite young readers to learn about vegetables. The layout is quite clever as it leverages contrast and comparison as a learning method. On one side of the page vegetables are depicted as they would appear growing in the garden while on the other side they are in the home being prepared for the dinner table. In addition, the nature side of the page illustrates the concept of opposites. For example, there are “tall” and “short” cornstalks. Orange carrot roots are “below” the ground, while the feathery green tops are “above”. The indoor side of the page features close-ups of vegetables against a wood-grain background that evokes a cutting board. Here children get a different perspective on the harvested veggies. We see shelled peas, open cornhusks and a cross-section of a pumpkin. The concluding series of images features an “empty” gardener’s basket next to a basket “full” of colourful vegetables on a blue and white gingham picnic tablecloth inlay.  This is primarily a picture book with only the names of the vegetables and the two opposing concepts appearing on each page. The typeset is Helvetica and is large and easy to read.  It is a sturdy board book and the inlays could not be easily ripped out or damaged. It is therefore a welcome addition to any toddler’s library. Other titles in the “I Like” series by Siminovich include: “I Like Toys “, “I Like Bugs” and “I Like Fruit”. “I Like Vegetables” is sure to engage children from ages 1-3. Highly recommended: 4 out of 4 stars Reviewer: Kim FrailKim is a Public Services Librarian at the H.T. Coutts Education Library at the University of Alberta. Children’s literature is a big part of her world at work and at home. She also enjoys gardening, renovating and keeping up with her two-year old. 

scholarly journals OBSERVATIONS ON THE FINE STRUCTURE OF THE DEVELOPING SPERMATID IN THE DOMESTIC CHICKEN

1962 ◽  
Vol 14 (2) ◽  
pp. 193-205 ◽  
Author(s):  
Toshio Nagano
Keyword(s):  
Plasma Membrane ◽  
Fine Structure ◽  
Cross Section ◽  
Neck Region ◽  
Structural Features ◽  
Dense Granule ◽  
Domestic Chicken ◽  
The Other ◽  
Dense Structure ◽  
Distal Centriole

The kinetic apparatus, the acrosome and associated structures, and the manchette of the spermatid of the domestic chicken have been studied with the electron microscope. The basic structural features of the two centrioles do not change during spermiogenesis, but there is a change in orientation and length. The proximal centriole is situated in a groove at the edge of the nucleus and oriented normal to the long axis of the nucleus and at right angles to the elongate distal centriole. The tail filaments appear to originate from the distal centriole. The plasma membrane is invaginated along the tail filaments. A dense structure which appears at the deep reflection of the plasma membrane is identified as the ring. The fine structure of the ring has no resemblance to that of a centriole and there is no evidence that it is derived from or related to the centrioles. The tail of the spermatid contains nine peripheral pairs and one central pair of tubular filaments. The two members of each pair of peripheral filaments differ in density and in shape: one is dense and circular, and the other is light and semilunar in cross-section. The dense filaments have processes. A manchette consisting of fine tubules appears in the cytoplasm of the older spermatid along the nucleus, neck region, and proximal segment of the tail. The acrosome is spherical in young spermatids and becomes crescentic and, finally, U-shaped as spermiogenesis proceeds. A dense granule is observed in the cytoplasm between acrosome and nucleus. This granule later becomes a dense rod which is interpreted as the perforatorium.

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