The Uptake and Distribution of Water in the Embryo of Xenopus Laevis (Daudin)

1962 ◽  
Vol 39 (1) ◽  
pp. 1-19
Author(s):  
P. H. TUFT
Keyword(s):  
Water Uptake ◽  
Close Agreement ◽  
Quantitative Description ◽  
Morphological Data ◽  
Tail Bud ◽  
Volume Changes ◽  
Qualitative And Quantitative ◽  
Quantitative Form ◽  
Intact Embryo ◽  
Sudden Decrease

1. The weight in water (reduced weight, or R.W.) of single Xenopus embryos has been measured throughout development at 25°C. and 20°C. using Cartesian diver balances. The R.W. remains constant from laying until the early tail-bud stages, after which it decreases slowly. 2. The density of intact embryos, and of open embryos from which the contents of the cellular cavities have been removed, has been measured at the same temperatures. 3. It is concluded that the observed changes in density are due to the uptake or loss of water from the embryo. 4. The volume changes calculated from the R.W. and the density show that from cleavage until the end of neurulation the volume of the embryo increases more and more rapidly. At the end of neurulation there is a sudden decrease in volume due to the emptying of the archenteron cavity. Thereafter the volume again increases, the rate decreasing again as the kidney becomes functional. 5. The volume of the cells, on the other hand, increases only slowly at first; but after the collapse of the archenteron, it increases more rapidly than that of the embryo as a whole. It is concluded that up to this time the water entering the embryo accumulates first in the blastocoel, then in the archenteron and finally in the cells. 6. An hypothesis that has been put forward to explain these changes in the distribution of water is restated in a quantitative form, and is used to calculate theoretical values for the rate of water uptake by the intact embryo from independent morphological data contained in the normal tables of Xenopus development. 7. Theoretical rates of water uptake based on this hypothesis are compared with the observed volume changes calculated from density and R.W. measurements. 8. The two sets of values are in close agreement and it is concluded that the hypothesis provides an adequate qualitative and quantitative description for some of the morphogenetic changes during early development of X. laevis.

Tracking of the effects of the plasticizer on the water uptake and free volume changes of methylcellulose

2007 ◽  
Vol 18 (11) ◽  
pp. 921-924 ◽  
Author(s):  
Klára Pintye-Hódi ◽  
Károly Süvegh ◽  
Tamás Marek ◽  
Romána Zelkó
Keyword(s):  
Free Volume ◽  
Water Uptake ◽  
Volume Changes

The role of water-regulating mechanisms in the development of the haploid syndrome in Xenopus laevis

Development ◽  
1972 ◽  
Vol 28 (2) ◽  
pp. 449-462
Author(s):  
Louie Hamilton ◽  
P. H. Tuft
Keyword(s):  
Xenopus Laevis ◽  
Cell Number ◽  
Gastrula Stage ◽  
Tail Bud ◽  
Volume Changes ◽  
Membrane Area ◽  
Flow Through ◽  
The Difference ◽  
Haploid Embryos

The uptake of water by haploid and diploid sibling embryos of Xenopus laevis has been investigated by measuring the density changes which occur during the development of intact embryos from the blastula to the late tail-bud stage, and of explants from which most of the presumptive endoderm has been removed. The results show that up to the mid-gastrula stage there is no difference between the haploid and diploid embryos; but from then on, whereas the diploid volume increases steadily, the haploid gastrulae undergo a series of cyclical volume changes due to loss of fluid through the blastopore. It is concluded that this is the result of an excessive inflow of water through the haploid ectoderm, because it was found that the volume of haploid ectodermal explants increased much more rapidly than the volume of similar diploid explants. Excess flow through the haploid ectoderm also accounts for other characteristics of the haploid syndrome – microcephaly and lordosis. It is suggested that it is the doubling of the cell number in haploid embryos with the consequent 25% increase in aggregate cell membrane area which accounts for the difference between the uptake of water by the two types of embryos. It is also suggested that changes in the rate of water flow through the ectoderm and endoderm which are thought to account for the accumulation of water in the blastocoel and archenteron in the normal diploid embryo arise in a similar way.

Morphological reassessment and new locality records for Galea comes Thomas, 1919 (Rodentia, Caviidae)

Mammalia ◽  
2019 ◽  
Vol 83 (6) ◽  
pp. 601-609
Author(s):  
Pablo Teta ◽  
María Carolina Madozzo-Jaén ◽  
Alexandra M.R. Bezerra ◽  
Pablo E. Ortiz ◽  
Sergio O. Lucero ◽  
...  
Keyword(s):  
South America ◽  
Related Species ◽  
Morphological Traits ◽  
Morphological Data ◽  
Closely Related Species ◽  
Northwestern Argentina ◽  
Qualitative And Quantitative ◽  
Distributional Range ◽  
Emended Diagnosis

Abstract The genus Galea Meyen, 1833 includes at least five species of terrestrial, diurnal and herbivorous cavies that occupy grasslands and rocky scrub areas at both high and low elevations in South America. According to the available molecular and morphological data, Galea comes Thomas, 1919 is restricted to highland areas above 2000 m in southern Bolivia and northwestern Argentina. Its distributional range as well as its morphological distinctiveness from other closely related species (Galea leucoblephara and Galea musteloides) is poorly documented. Using both qualitative and quantitative morphological traits, we provided an emended diagnosis for G. comes. In addition, we added six new locality records to its known distribution.

Kinetics of inactivation of staphylolytic enzymes: Qualitative and quantitative description

Biochimie ◽  
2019 ◽  
Vol 162 ◽  
pp. 77-87
Author(s):  
Lyubov Filatova ◽  
David Donovan ◽  
Steven Swift ◽  
Vladimir Pugachev ◽  
Georgy Emelianov ◽  
...  
Keyword(s):  
Quantitative Description ◽  
Qualitative And Quantitative ◽  
Kinetics Of

A review of the ecology of the deep-water pelagic fauna of the Rockall Trough

1986 ◽  
Vol 88 ◽  
pp. 145-157
Author(s):  
J. Mauchline
Keyword(s):  
Deep Water ◽  
Quantitative Description ◽  
Demersal Fish ◽  
Historical Account ◽  
Production Rates ◽  
Qualitative And Quantitative ◽  
The North ◽  
Rockall Trough

SynopsisA brief historical account of the early faunal investigations is given. Modern studies concentrate on qualitative and quantitative description and interpretation of the processes taking place within the Rockall Trough. Demographic analyses are feasible on a variety of species allowing estimation of growth and production rates. The pelagic fauna impinges on the benthopelagic environments of the slope regions of the Trough. There it is predated by populations of demersal fish. Advection of fauna takes place to the north and northeast, probably primarily in the slope current.

Aerial pursuit flights in the shoveler

1974 ◽  
Vol 52 (12) ◽  
pp. 1473-1480 ◽  
Author(s):  
Norman R. Seymour
Keyword(s):  
Breeding Season ◽  
Quantitative Description ◽  
Wild Birds ◽  
Flight Behavior ◽  
Territorial Defense ◽  
Qualitative And Quantitative ◽  
Active Mechanism ◽  
Seasonal Basis ◽  
Males And Females

Analysis of 266 pursuit flights of wild birds provided a qualitative and quantitative description of aspects of this phenomenon. Flight behavior and frequency were analyzed for the general prelaying, laying, incubation, and renesting periods.Flight behavior of pursued males and females and that of the pursuing male varied little throughout the breeding season. No difference was detected on a daily basis.Flight frequency was greatest during the morning (0500 to 1000 h) period throughout the season. On a seasonal basis, frequency was greatest during territory establishment and declined after general incubation began. Another peak of activity occurred during the renesting period. Frequency during all periods reflected the number of non-territorial pairs interacting with territorial pairs.Attempted rape and associated flight was rare, with most flights apparently resulting from hostility associated with territorial defense. The pursuer was invariably a territorial male.The pursuit flight functioned in the establishment and maintenance of territories and was the major active mechanism in the spacing of breeding pairs.

scholarly journals PENERAPAN MODEL PEMBELAJARAN LRD (LISTEN, READ AND DISCUSS) UNTUK MENINGKATKAN KETERAMPILAN MEMBACA SISWA KELAS X IPA 2 SMAN 1 PRINGGARATA

2021 ◽  
Vol 1 (2) ◽  
pp. 149-158
Author(s):  
JUPRI JUPRI
Keyword(s):  
High School ◽  
Action Research ◽  
Learning Process ◽  
Teaching And Learning ◽  
Quantitative Description ◽  
Reading Skill ◽  
Qualitative Description ◽  
Qualitative And Quantitative ◽  
Tenth Grade ◽  
Written Test

This study concerns with Listen Read Discuss (LRD) to promote students’ reading skill. The aim of this study was to promote students’ reading skill through (LRD) technique . In this study, the researcher used classroom action research in which the datas were described in qualitative and quantitative description using the instruments of observation checklist, test and documentation. Observation was conducted to know the implementation of (LRD) technique during teaching and learning process and its datas were decribed in qualitative description, while test used to measure the students’ achievement in reading skill in form of a written test and described in quatitative description. Subject of this study was tenth- grade of SMAN 1 Pringgarata which consists of 30 students.This study was conducted in two cycles, each cycle consisted of 4 steps such as: planning, acting, observing and reflecting. The result of this research showed that (LRD) technique could promote students’ reading skill. It could be seen from the significant improvement of result in each cycle. The average of students’ score before implementing the strategy was 47, and increased into 61 in the first cycle . After doing treatment and it increased into 81 in second cycle. It means, students’ reading skill was improved and successful by applying (LRD) technique at the tenth-grade of senior high school, SMAN 1 Pringgarata. ABSTRAKPenelitian ini fokus untuk mengkaji penerapan model pembelajaran LRD (Learn Read Discuss) untuk meningkat keterampilan membaca siswa. Tujuan dari penelitian ini adalah untuk memaparkan perencanaan, pelaksanaan dan evaluasi peningkatan keterampilan membaca pada siswa kelas X IPA 2 SMA Negeri 1 Pringgarata dengan menggunakan model pembelajaran LRD (Listen Read Discuss). Penelitian ini merupakan penelitian tindakan kelas (PTK) yang datanya dipaparkan melalui data deskripsi kualitatif dan kuantitatif. Penelitian ini dilaksanakan dalam dua siklus. Setiap siklus terdiri dari atas 4 tahap yaitu: tahap perencanaan, pelakasanaan (tindakan), observasi dan refleksi. Data proses pembelajaran setiap siklus dianalisis secara deskriptif kualitatif sedangkan data hasil pembelajaran dianalisis secara deskriptif kuantitatif. Subjek penelitian ini adalah siswa kelas X IPA 2 yang berjumlah 30 orang. Hasil penelitian sebelum diterapkan LRD adalah 47,00 setelah dilakukan tindakan menunjukkan bahwa nilai yang diperoleh siswa pada siklus I meningkat menjadi 61,00 dan pada siklus II mencapai 81,00. Nilai prolehan ini sudah melampaui angka KKM yang diisyaratkan pada mata pelajaran bahasa Inggris di kelas X SMAN 1 Pringgarata Tahun Pelajarn 2021/2022 yaitu 75. Hasil penelitian menunjukkan bahwa pembelajaran dengan model LRD dapat meningkatkan keterampilan membaca, khusunya keterampilan membaca jenis teks rcount, siswa kelas X IPA2 SMA Negeri 1 Pringgarata.

scholarly journals The Methanol Adsorption in Microporous Alumina Agglomerates

2019 ◽  
Vol 3 (1) ◽  
pp. 22
Author(s):  
Grygorii Dragan ◽  
Volodymyr Kutarov ◽  
Mykola Poletaiev ◽  
Kyrylo Kolesnykov ◽  
Mariya Khlebnikova
Keyword(s):  
Aluminum Oxide ◽  
Adsorption Equilibrium ◽  
Capillary Condensation ◽  
Quantitative Description ◽  
Gas Dispersion ◽  
Volume Filling ◽  
Qualitative And Quantitative ◽  
Methanol Adsorption ◽  
Adsorption Desorption ◽  
Open Slit

We have studied theoretical and experimental methods of methanol adsorption in micropores of aluminum oxide agglomerates obtained by gas-dispersion synthesis. It is shown that the necessity to use strict equations based on the theory of volume filling of micropores, which implies a physical and formal analogy between the volume filling of micropores and capillary condensation, for qualitative and quantitative description of adsorption equilibrium in open slit-like micropores. The applicability of the proposed equations for the description of adsorption equilibrium in such systems is demonstrated on the example of experimental methanol adsorption/desorption isotherm on the aluminum oxide, which possesses a microporous structure.

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