The Pluripotency of the Pharyngeal Primordium in Urodelan Neurulæ1

Development ◽  
1957 ◽  
Vol 5 (4) ◽  
pp. 438-448
Author(s):  
Tokindo S. Okada
Keyword(s):  
Digestive Tract ◽  
Long Time

It was for a long time taken for granted that determination of the primordia of the endodermal organs of Amphibia occurs prior to gastrulation (cf. Holtfreter, 1938 a, b; Stableford, 1948). There have been, however, some data which seem to conflict with this statement. For instance, after the extirpation of some endodermal primordium or primordia from neurulae or more advanced embryos of urodeles, the remaining endoderm shows regulative development into an almost complete digestive tract, no deficiency of any endodermal organs being encountered (Balinsky, 1948; Okada, 1953; Mikami & Murakawa, 1954). Moreover, when a small endodermal fragment from a gastrula or neurula is transplanted into a heterotopic site of another embryo, its resulting differentiation is not bedeutungsgemäss, but ortsgemäss in many cases (Balinsky, 1938, 1948). Judging from these findings, we cannot help concluding that each endodermal primordium is not in a state of final determination even after gastrulation, although, of course, it may be possible that labile determination has already begun at a much earlier stage.

Tingkat Pemahaman Kompetensi Guru Pada Mahasiswa Pendidikan Geografi Sebagai Calon Guru Geografi

2020 ◽  
Vol 21 (1) ◽  
pp. 102-117
Author(s):  
Novia Zalmita ◽  
Muhajirah Muhajirah ◽  
Abdul Wahab Abdi
Keyword(s):  
Prospective Teachers ◽  
Prospective Teacher ◽  
Quantitative Description ◽  
Population Data ◽  
Geography Education ◽  
Teacher Competence ◽  
Education Department ◽  
Long Time

One that influences human resource indicators is education. The teacher is a profession as a job of academic specialization in a relatively long time in college. Understanding related to teacher competence is very important to have by a prospective teacher because it can affect the quality of performance as a professional teacher. The teacher's competence is known as pedagogic, professional, social and personality competencies. The issue in this study is how the competency of the teacher of the Department of Geography Education FKIP Unsyiah as a prospective teacher of geography? The purpose of this study was to determine the competence of teachers in the Department of Geography Education FKIP Unsyiah as prospective geography teachers. Quantitative description approach is used in this study to find answers to the issue. The population in this study were students of the Department of Geography Education FKIP Unsyiah class of 2015 and 2016 who had been declared to have passed the Micro Teaching and Magang Kependidikan 3 course totaling 50 people. Because the population is small and can be reached, the determination of the sample using total sampling techniques so that the sample in this study is the whole population. Data collection is done by distributing test questions to respondents. The data was analyzed using the descriptive statistics percentage formula. The results of the study indicate that the level of teacher competence of Geography Education Department students as prospective teachers is in the moderate category, namely as many as 22 respondents (44%). A total of 12 respondents (24%) were in the high category, 15 respondents (30%) were in the low category and 1 respondent (2%) were in the very low category.

scholarly journals Expression Level of Mature miR172 in Wild Type and StSUT4-Silenced Plants of Solanum tuberosum Is Sucrose-Dependent

2021 ◽  
Vol 22 (3) ◽  
pp. 1455
Author(s):  
Varsha Garg ◽  
Aleksandra Hackel ◽  
Christina Kühn
Keyword(s):  
Solanum Tuberosum ◽  
Wild Type ◽  
Potato Plants ◽  
Mature Leaves ◽  
In Vitro Plantlets ◽  
Long Time ◽  
Short Time ◽  
Cut Leaves

In potato plants, the phloem-mobile miR172 is involved in the sugar-dependent transmission of flower and tuber inducing signal transduction pathways and a clear link between solute transport and the induction of flowering and tuberization was demonstrated. The sucrose transporter StSUT4 seems to play an important role in the photoperiod-dependent triggering of both developmental processes, flowering and tuberization, and the phenotype of StSUT4-inhibited potato plants is reminiscent to miR172 overexpressing plants. The first aim of this study was the determination of the level of miR172 in sink and source leaves of StSUT4-silenced as well as StSUT4-overexpressing plants in comparison to Solanum tuberosum ssp. Andigena wild type plants. The second aim was to investigate the effect of sugars on the level of miRNA172 in whole cut leaves, as well as in whole in vitro plantlets that were supplemented with exogenous sugars. Experiments clearly show a sucrose-dependent induction of the level of mature miR172 in short time as well as long time experiments. A sucrose-dependent accumulation of miR172 was also measured in mature leaves of StSUT4-silenced plants where sucrose export is delayed and sucrose accumulates at the end of the light period.

scholarly journals Hydrological response to different time scales of climatological drought: an evaluation of the Standardized Precipitation Index in a mountainous Mediterranean basin

2005 ◽  
Vol 9 (5) ◽  
pp. 523-533 ◽  
Author(s):  
S. M. Vicente-Serrano ◽  
J. I. López-Moreno
Keyword(s):  
Time Scales ◽  
Hydrological Cycle ◽  
Standardized Precipitation Index ◽  
Precipitation Index ◽  
Drought Indices ◽  
Long Time ◽  
The Standardized Precipitation Index ◽  
Hydrological Droughts ◽  
Different Time Scales

Abstract. At present, the Standardized Precipitation Index (SPI) is the most widely used drought index to provide good estimations about the intensity, magnitude and spatial extent of droughts. The main advantage of the SPI in comparison with other indices is the fact that the SPI enables both determination of drought conditions at different time scales and monitoring of different drought types. It is widely accepted that SPI time scales affect different sub-systems in the hydrological cycle due to the fact that the response of the different water usable sources to precipitation shortages can be very different. The long time scales of SPI are related to hydrological droughts (river flows and reservoir storages). Nevertheless, few analyses empirically verify these statements or the usefulness of the SPI time scales to monitor drought. In this paper, the SPI at different time scales is compared with surface hydrological variables in a big closed basin located in the central Spanish Pyrenees. We provide evidence about the way in which the longer (>12 months) SPI time scales may not be useful for drought quantification in this area. In general, the surface flows respond to short SPI time scales whereas the reservoir storages respond to longer time scales (7–10 months). Nevertheless, important seasonal differences can be identified in the SPI-usable water sources relationships. This suggests that it is necessary to test the drought indices and time scales in relation to their usefulness for monitoring different drought types under different environmental conditions and water demand situations.

VI. The glucoside constitution of proteid matter

1894 ◽  
Vol 54 (326-330) ◽  
pp. 53-57 ◽  
Keyword(s):  
Sulphuric Acid ◽  
Cupric Oxide ◽  
The Body ◽  
Long Time

For a long time I have adopted a process for separating the glycogen of the liver consisting in boiling with potash, pouring into alcohol, and collecting the precipitate. For the purpose of estimation, the precipitated glycogen was converted by means of sulphuric acid into glucose, the determination of which gave the information required. I afterwards applied the process to blood, and the various organs and tissues of the body, with the result that a more or less notable amount of cupric oxide reducing product was obtained, which I at the time looked upon as taking origin, as in the case of the liver, from glycogen.

Table II : Quantitative determination of carbonyl compounds at different odour sources (concentrations in ppb) Rendering plant Gelatine plant neighbourhood neighbourhood Formaldehyde 40 16 Acetaldehyde 39 24 Acetone 36 73 Prcpanal 10 -Isobutyraldehyde 10 30 Pentanal 15 19 Hexanal 3.52 Heptanal 12.5 Octanal 10.5 Nonanal 1 2 acids (figure 7). However extractions always involve a serious decrease in sensitivity, while evaporation of the extract produces a solution in 0.1-0.5 ml of solvent, and only 1 pi of it can be brought in the gas chromatograph. Therefore work is in progress to enhance sensitivity by converting acids in­ to halogenated derivatives, which can be GC-analysed with the more sensitive electron-capture detector. For thiols a similar procedure is investigated as with aldehydes. One possibility is absorption of thiols in an alkaline solution and reaction with 2,4-dinitrochlorobenzene, yielding 2,4-dinitrofenylsulfides, which are analysed by HPLC (9). Sane improvements on removal of reagents at the one hand and on separation of sane by-products on the other hand have to be achieved in order to in­ crease the sensitivity with another factor of ten. 5. CONCLUSION The actual scope and limitations of chemical analysis of odour show that all problems can be tackled as far as emission is concerned. For iititiission measurements seme progress is necessary, but there is no essential reason why chemical analysis would be unable to attain the desired sensitivity for all types of odorants. There is no doubt that in a few years the last dif­ ficulties will be solved. In order to achieve real control of odour nui­ sance, automatic measurement is necessary on a long time basis. There again seme technical development is to be expected. Does this mean that machines are going to decide if an odour is pre­ sent or not? By no means, while the population will always be the reference, and psychophysical measurements will be necessary to make chemical analysis possible.

1986 ◽  
pp. 171-171
Keyword(s):  
Chemical Analysis ◽  
Quantitative Determination ◽  
Alkaline Solution ◽  
Automatic Measurement ◽  
The Other ◽  
Long Time ◽  
Time Basis ◽  
The One ◽  
By Products

scholarly journals The investigation of the state of Ukraine furniture industry development under current economic conditions

2021 ◽  
Vol 68 (1) ◽  
pp. 174-184
Author(s):  
N. Bondarenko ◽  
D. Udalykh
Keyword(s):  
Positive Impact ◽  
State Regulation ◽  
Economic Conditions ◽  
Foreign Direct Investments ◽  
Furniture Industry ◽  
Number Increase ◽  
Long Time ◽  
Business Entities ◽  
Design Diversity

Furniture for a long time has been an integral component of human activity, recreation and everyday life. Its design, diversity and versatility along with the development of human civilization is increasingly becoming the object of further improvement. At present furniture production in Ukraine is the developing industry, gradually entering the European market in terms of quality and design. European furniture market is extremely attractive to operators and, therefore, has dynamics towards the competitor number increase. One of the factors of increasing the industry attractiveness is the support of amendments to the Law of Ukraine «On peculiarities of state regulation of business entities related to the sale and export of timber» by the Verkhovna Rada of Ukraine in April 2015, which imposed temporary, gradual prohibition on the export of raw timber (forest logs) for 10 years. The corresponding partial prohibition entered into force on 11.01.2015, and complete prohibition (including pine wood) - from January 1, 2017. The consequences of this moratorium during the first five years of its operation, which is important in the context of politicization of this problem are analyzed in this paper. The dynamics and structure of the amount of enterprises in industry and the number of employees employed in them are investigated. The volume of furniture industry sales in general and the areas of their implementation (internal or external markets) are analyzed. The next stage is the analysis of the dynamics of the ratio of furniture products exports and imports in Ukraine and determination of the major exporters of such products. The final stage is the investigation of the dynamics of foreign direct investments in the enterprises capital share in this industry in order to identify its investment attractiveness. As a result, it is determined that the introduced moratorium has partial positive impact on the development of furniture industry in Ukraine. However, at present, the furniture industry is not attractive enough for new foreign investment. This is the consequence of significant amount of «shadow» production, which in its turn destabilizes the situation in the furniture market. Ukrainian manufacturers will be able to strengthen their position in domestic market and even abroad, if they solve the main problems in furniture production and eliminate all disincentives.

scholarly journals Determination of trace elements in some fruits collected in Vietnam and Korea by Neutron Activation Analysis on Dalat and HANARO research reactors

2015 ◽  
Vol 5 (4) ◽  
pp. 23-29
Author(s):  
Thi Sy Nguyen ◽  
Manh Dung Ho ◽  
Van Doanh Ho ◽  
Quang Thien Tran ◽  
Sam Chung Yong
Keyword(s):  
Trace Elements ◽  
Neutron Activation Analysis ◽  
Activation Analysis ◽  
Neutron Activation ◽  
Research Reactor ◽  
Standard Samples ◽  
Long Time ◽  
Polyethylene Bags ◽  
Mn Concentrations

The k0-based neutron activation analysis (k0-NAA) has been applied for determination of trace multi-element in 5 fruits: Orange, tomato, persimmon, pear and apple. The samples were collected in Vietnam and Korea, and dried-frozen in laboratory at a temperature of -650C, weighed approximately 50 mg or 100 mg each sample, and put in clean polyethylene bags for short and long time irradiations, respectively. The NIST-1547 (Peach Leaves) and IAEA-V-10 (Hay Powder) were used for the purpose of quality control. Both analytical and standard samples were irradiated in the 500 kW Dalat research reactor (Vietnam) and the 20 MW HANARO research reactor (Korea). Concentration of 16 elements: Al, As, Au, Br, Ca, Cl, Co, Eu, Fe, K, La, Mg, Mn, Na, Rb and Zn were determined. By comparison the concentrations of trace elements in the investigated Vietnam and Korea’s fruits, revealed that they are mostly similar between two places. However, the Ca concentration in orange from Vietnam was approximately 2.5 times higher than that one from Korea, whereas the Ca concentration in pear from Vietnam was approximately 21 times lower than that one from Korea. The Mn concentrations in all of fruits that collected in Vietnam were mostly higher than those collected in Korea, ranging between 1.4 to 2.2 times.

Reactive Diffusion at the Cylindrical Dissolving of Copper in the Solder Melt

2011 ◽  
Vol 312-315 ◽  
pp. 387-392 ◽  
Author(s):  
Jaromír Drápala ◽  
Alena Struhařová ◽  
Daniel Petlák ◽  
Vlastimil Vodárek ◽  
Petr Kubíček
Keyword(s):  
Time Course ◽  
Solid Phase ◽  
Accurate Determination ◽  
Theoretical Description ◽  
Reactive Diffusion ◽  
Interface Boundary ◽  
Boundary Movement ◽  
Long Time ◽  
Melt Cooling

Problems of reactive diffusion at the solid phase and melt contact were studied theoretically and experimentally. The main intention was to calculate the time course of the solid phase dissolving in the case of cylindrical dissolving. These calculations were carried out on the assumption for the rate constant of dissolving K = const. In our work we give heed especially to the dominating process, which is the solid metal A dissolved in the melt B. During the dissolving the melt B saturates with the metal A and the process is influenced by convections which are characteristic for the given experimental configuration. A theoretical description of the kinetics of the solid phase dissolving in the melt will be presented for the case of cylindrical dissolving. The aim is to derive a relation for the interface boundary movement c(t) in dependence on time and a time course of growth of the element A concentration in the melt B. There are problems with accurate determination of the interface boundary movement after certain heating times of specimens, when it is observed experimentally, since intermetallic phases create in the original A metal at both the diffusion and cooling and some phases segregate at the solidifying melt cooling. The main intention was an experimental study of the copper dissolving in the tin melt. Experiments aimed to the determination of the Cu wires (diameters from 0.5 to 3.5 mm) dissolution in the solder melt were carried out at various selected temperatures and times. Rapid growth of phases in the metal A and determination of the thickness of layers with these phases pose considerable time demands to X-ray micro-analyses (WDX, EDX) of specimens after their long-time heating.

scholarly journals Commission 19: Rotation of the Earth

1985 ◽  
Vol 19 (1) ◽  
pp. 193-205 ◽  
Author(s):  
Ya. S. Yatskiv ◽  
W. J. Klepczynski ◽  
F. Barlier ◽  
H. Enslin ◽  
C. Kakuta ◽  
...  
Keyword(s):  
Time Frame ◽  
Laser Ranging ◽  
Earth’S Rotation ◽  
The Moon ◽  
Earth's Rotation ◽  
The Earth ◽  
Long Time ◽  
Terrestrial Reference System ◽  
Rotation Of The Earth

During the period, work on the problem of the Earth’s rotation has continued to expand and increase its scope. The total number of institutions engaged in the determination of the Earth’s rotation parameters (ERP) by different techniques has been increased significantly. The rotation of the Earth is currently measured by classical astrometry, Doppler and laser satellite tracking, laser ranging of the Moon, and radio interferometry. Several long time series of the ERP are available from most of these techniques, in particular, those made during the Main Campaign of the MERIT project. The various series have been intercompared and their stability, in the time frame of years to days, has been estimated for the purposes of establishing a new conventional terrestrial reference system (COTES). On the other hand, the difficulties of maintaining a regular operation for laser ranging to the Moon (LLR) have been recognized. It resulted in the proposal to organize an one-month campaign of observations in 1985 in order to complement the COTES collocation program and to allow additional intercomparisons with other techniques.

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