Effets de la thymectomie néonatale sur la teneur en magnésium du plasma et de quelques tissus du rat

1975 ◽  
Vol 53 (3) ◽  
pp. 501-503
Author(s):  
P. Deschaux ◽  
Binimbi-Massengo ◽  
Y. Charnot ◽  
R. Fontanges
Keyword(s):  
Marked Decrease ◽  
Magnesium Content ◽  
Magnesium Level ◽  
The Other ◽  
Indirect Pathway ◽  
Protein Factor ◽  
White Rats ◽  
Other Hand

White rats were thymectomized neonatally. After 60 days, no alteration was noted in the plasma or testis magnesium level. On the other hand, a marked decrease was observed in the magnesium content of muscle (−23%) and of bone (−19%). The injection of thymosin reversed these changes. These findings suggest that a correlation between the thymus and the muscle is exerted by a protein factor (thymosin), and that the thymus may act on sex glands through an indirect pathway.

scholarly journals The significance of soil microorganisms as a limiting factor in infection of clover by Sclerotinia trifoliorum erikss. at different times of the year

1964 ◽  
Vol 36 (1) ◽  
pp. 120-134
Author(s):  
Anna-Marja Halkilahti
Keyword(s):  
Soil Microorganisms ◽  
Soil Microbes ◽  
Marked Decrease ◽  
Petri Dish ◽  
Soil Samples ◽  
Pronounced Effect ◽  
The Other ◽  
Limiting Factor ◽  
Sclerotinia Trifoliorum ◽  
Other Hand

In the petri dish trials the mycelia of Sclerotinia trifoliorum in sterilized soil samples generally infected clover quite readily. In unsterilized samples the infection was less severe and showed marked variations in different years and at different times of the year. In the outdoor trials clover became less infected in the middle of the summer than in the spring and autumn. On the other hand, in the thermostat trials, where the temperature was constantly 7—10°C, the temperature at the time of taking the soil samples did not have a pronounced effect on the extent of clover infection. Liming of the soil caused a marked decrease in the severity of clover rot infection. In some autumns clover plants growing in soil samples taken from fallow were more seriously infected than those growing in soil from a clover field. As a rule, however, there were only slight variations in the extent of infection in the soil samples taken at the same time from the various areas of the field cultivated in different ways. In general, the highest numbers of microorganisms in the soil were found in the autumn and the lowest in the spring. In clover fields there were often more microorganisms – particularly in the autumn – than in fallow. Liming caused an increase in the numbers of soil microbes. S. trifoliorum infected clover very severely at temperatures of 0—5°C; in the range 5—21°C the infection grew generally milder the more the temperature was found to be rising. At temperatures of 5– 10°C an increase in the numbers of soil microbes resulted in a decrease in the infection of the clover. Still higher temperatures, which did not increase the numbers of soil microorganisms, nevertheless enhanced the antagonistic power of the soil.

scholarly journals TUMOR INOCULATION INTO ORGANS AND THE ANALOGY BETWEEN HUMAN CANCER AND THE TUMORS OF WHITE MICE AND WHITE RATS

1912 ◽  
Vol 16 (2) ◽  
pp. 155-164 ◽  
Author(s):  
Isaac Levin
Keyword(s):  
Cancer Research ◽  
Human Cancer ◽  
Subcutaneous Tissue ◽  
A Priori ◽  
The Other ◽  
Biological Behavior ◽  
Great Promise ◽  
White Rats ◽  
Other Hand ◽  
Subcutaneous Inoculation

The analysis of the experiments described above indicates that tumors of the white rat or white mouse inoculated into parenchymatous organs acquire a different biological character from those inoculated subcutaneously. The latter are a great deal more benign in their behavior than human cancer or spontaneous tumors in the same species of animals. Tumors inoculated into organs, on the other hand, are quite identical in their biological behavior with the malignant tumors of animal and man. A conclusion must then be drawn, even a priori, that the method of inoculation into organs is a very important aid in the experimental investigation of cancer. It is true that the method is a great deal more complicated and time-consuming than the ordinary subcutaneous inoculation. The subcutaneous method is satisfactory for a number of cancer problems. One of these is the study of general susceptibility and resistance of the organism of the host to the inoculation of the tumors, and this is a subject of paramount importance in cancer research. On the other hand, the investigations of the writer (10) have shown that an animal may be susceptible to a subcutaneous inoculation of a certain tumor and resist the inoculation of the same tumor into the testicle. Undoubtedly this method of inoculation will reveal the existence of a number of other phenomena. The discovery of specific therapeutic measures is certainly the greatest problem in cancer research. A great deal of work has been done already on the subject, and the latest investigations of Wassermann on the chemotherapy of experimental tumors seem to be of great promise. But here also the therapeutic methods must be tried on animals in which the inoculations of tumor cells have been made into parenchymatous organs before the growths thus treated will have any analogy to human cancer. In this connection one must bear in mind the fact that all the empirical so-called specific cancer remedies, which are continually being devised, are usually successful in treating localized skin cancers and fail utterly in the malignant growths of the internal organs. It is comparatively easy to produce a localized necrosis and softening in a circumscribed growth of the skin and subcutaneous tissue, but whether the same result will be produced on a diffuse and better nourished tumor growing inside of a parenchymatous organ cannot be decided a priori. To determine this it is necessary to have experimental proof on animals in which the tumor was inoculated into organs.

Oestrous activity of Egyptian fat-tailed Ossimi ewes raised at different locations

1984 ◽  
Vol 103 (3) ◽  
pp. 481-486 ◽  
Author(s):  
A. M. Aboul-Naga ◽  
M. B. Aboul-Ela
Keyword(s):  
High Frequency ◽  
Marked Decrease ◽  
The Other ◽  
Lower Activity ◽  
Other Hand ◽  
Teaser Rams

SummaryOestrous activity of three flocks of Ossimi, subtropical fat-tailed ewes was detected by teaser rams over a calendar year. The flocks were raised at north Delta, mid-Delta and middle Egypt.The two Delta flocks showed irregularity in percentage of ewes coming into oestrus monthly, with a marked decrease in March, April and May, April being the lowest. On the other hand, the mid-Egypt flock showed consistent oestrous activity throughout the year, with small fluctuations.The three flocks showed month-to-month variation in incidence of oestrus per ewe, with lower activity in the spring months. Neither of the two Delta flocks showed real regular oestrous activity in any month throughout the year, with high ewe variation. Some ewes showed regular activity throughout the year (16–20 cycles), whereas some others showed only 4–7 cycles per year.There were two periods of the year with high frequency of anoestrus. The more intense was March–May while fewer ewes had an anoestrous period in July–August. This was the case in the three flocks but with varying intensity.A period of more than 1 year of detecting oestrus affected oestrous performance of the ewes and should be avoided.

Some Effects of Reward on the Strength of Position Stereotypes in the White Rat

1952 ◽  
Vol 4 (2) ◽  
pp. 78-86 ◽  
Author(s):  
F. Knöpeelmacher
Keyword(s):  
Sex Differences ◽  
Present Experiment ◽  
The Other ◽  
Special Treatment ◽  
Problem Situation ◽  
Response Patterns ◽  
White Rats ◽  
Other Hand ◽  
Soluble Problem

Certain aspects of Maier's hypothesis that rigid behaviour stereotypes elicited in an insoluble problem situation are not explicable in terms of goal-motivated learning were tested thus: Forty-one white rats of Wistar stock were exposed to an insoluble problem in a water discrimination unit. Each of the twenty-four animals who formed position stereotypes was assigned to one of four groups. One of these groups served as a control and received no special treatment. Each of the remaining three experimental groups was given a different number of successively rewarded trials to the side of the stereotype. Finally, all groups were presented with a soluble problem, and the strengths of the stereotypes in each group observed in terms of the breaking of the stereotypes. It was found that the strength of the stereotype behaviour was directly proportional to the number of rewarded trials. None of the stereotypes was sufficiently rigid to meet Maier's criterion of “fixated” response patterns. More stereotypes were formed by males than females. On the other hand no sex differences appeared in the subsequent behaviour of animals who did form stereotypes. These results are interpreted as showing that stereotyped responses formed under conditions of the present experiment are not qualitatively different from learned responses.

Relations of yolk, albumen and egg weight in inbred lines of brown leghorns

1954 ◽  
Vol 45 (1) ◽  
pp. 32-35 ◽  
Author(s):  
J. E. Erasmus
Keyword(s):  
Egg Size ◽  
Marked Decrease ◽  
Inbred Lines ◽  
Negative Association ◽  
The Other ◽  
Egg Weight ◽  
Reciprocal Crosses ◽  
Other Hand ◽  
Independent Variation ◽  
Pure Lines

1. The relations of yolk, albumen and egg weight were studied in seven inbred lines of Brown Leghorns and reciprocal crosses of two of these lines.2. In all the lines the eggs produced by hens had a bigger proportion of yolk than those produced by pullets.3. Besides changes in both components accompanying differences in egg size the line means for albumen weight still differ significantly after adjustment is made for its covariance with yolk weight. This independent variation leads to differences in the yolk-albumen ratio of the hens.4. Within the lines there is a significant negative association between egg size and the yolk/albumen ratio.5. The wide differences in egg size, dividing the pure lines into two groups characterized by large and small eggs respectively, resulted from a marked decrease in the amount of albumen in the eggs of the latter group. Yolk weights, on the other hand, could be ranked in a fairly regular series with adjacent lines differing by 2 g. or less.6. There is some source of variation in the yolk/ albumen ratio for line means which is not accounted for by differences in egg size.

scholarly journals Nutrient and Anti-Nutrient Composition of Four Rice Varieties in Port Harcourt Metropolis

2021 ◽  
pp. 90-100
Author(s):  
Gabriel O. Wordu ◽  
Achese Catherine Orisa ◽  
Mercy Ameka Hamilton China
Keyword(s):  
Rice Variety ◽  
Nutrient Content ◽  
Magnesium Content ◽  
The Other ◽  
Crude Fibre ◽  
Rice Varieties ◽  
Nutrient Analysis ◽  
Other Hand ◽  
Saponin Content ◽  
Port Harcourt

This study evaluated the nutrient and anti-nutrient content of four rice varieties in Port Harcourt metropolis. Four rice varieties (Tomato gold TG, Mama’s pride MP, Ultimate gold UG and daily choice DC) were used in this study. The rice varieties were purchased, milled into fine flour and evaluated for proximate, mineral and anti-nutrient analysis using standard methods. Proximate composition of the rice varieties revealed that moisture content ranged from 11.51-12.80%, ash (0.45-0.60%), fat (0.39-1.39%), crude protein (5.73-6.07%), crude fibre (0.90-6.85%) and carbohydrate (73.67-80.09%). Mama’s pride rice variety contained higher ash and fat contents while Tomatoes gold had significantly higher crude fibre. On the other hand, ultimate gold rice variety contained higher protein and carbohydrate; however, ash, protein and moisture contents did not vary significantly (p>0.05) between the rice varieties. Mineral composition of the rice varieties also showed that magnesium content ranged from 6.28-9.63 mg/100 g, calcium (3.74-8.23mg/100g) and iron (1.50-5.48mg/100g). The concentration of these mineral elements was found to be superior in ultimate gold rice variety. Phenol content of the rice varieties ranged from 9.92-14.58mg/100g, phytate (1.22-1.53g/kg), saponin (5.86-6.37%), tannin (47.03-66.89 mg/100 g) and flavonoid (2.29-2.80%). Ultimate gold rice variety also contained higher concentrations of phenol and tannins while saponin content was higher in daily choice rice variety. Phytate content on the other hand did not vary significantly (p>0.05) between the rice varieties. The result therefore revealed that ultimate gold rice variety contained a considerable amount of nutrients and should be highly recommended to consumers for derivation of the above-mentioned nutrients.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

Can the Academic Self-Concept be Positive and Realistic?

2005 ◽  
Vol 19 (3) ◽  
pp. 129-132 ◽  
Author(s):  
Reimer Kornmann
Keyword(s):  
Academic Performance ◽  
Opposite Effect ◽  
Self Esteem ◽  
Point Of View ◽  
The Other ◽  
Self Concept ◽  
High Ability ◽  
Self Image ◽  
Other Hand

Summary: My comment is basically restricted to the situation in which less-able students find themselves and refers only to literature in German. From this point of view I am basically able to confirm Marsh's results. It must, however, be said that with less-able pupils the opposite effect can be found: Levels of self-esteem in these pupils are raised, at least temporarily, by separate instruction, academic performance however drops; combined instruction, on the other hand, leads to improved academic performance, while levels of self-esteem drop. Apparently, the positive self-image of less-able pupils who receive separate instruction does not bring about the potential enhancement of academic performance one might expect from high-ability pupils receiving separate instruction. To resolve the dilemma, it is proposed that individual progress in learning be accentuated, and that comparisons with others be dispensed with. This fosters a self-image that can in equal measure be realistic and optimistic.

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