scholarly journals The γ-rays from actinium emanation and their origin

As a result of recent experiments, evidence is accumulating that the pene­trating γ -rays from radioactive substances have their origin not in the movement of electrons but in the transitions of α -particles in an excited nucleus. Strong evidence in support of this view was obtained by Rutherford, Ward and Lewis from their analysis of the groups of long range α -particles from radium C', and a more detailed discussion of the results was given by Rutherford and Ellis. This problem of the origin of the γ -rays can be attacked in another direction from a consideration of the so-called fine structure shown by the groups of α -particles emitted by certain radioactive substances. In particular, Rosenblum found that the transformation of thorium C was accompanied by the appearance of five homogeneous groups of α -particles. In explanation of these results, Gamow suggested that γ -rays should be emitted as a result of such a complex transformation, the energies of the individual γ -rays corre­sponding to the differences of energies between the α -particles in the various groups. Unfortunately it is a difficult matter to give a decisive answer on this important question. In a recent paper, Ellis concludes that the experimental evidence is in support of Gamow’s theory, but on the other hand, Meitner as a result of her investigations, has expressed a contrary opinion. It is thus of much impor­tance to examine all methods of obtaining evidence on this question.

The excitation of γ -rays by the impact of β -rays on different substances has been investigated by several observers. The question was first systematically examined by J. A. Gray. He showed that penetrating γ -rays are produced by the β -rays of radium E when they impinge on different materials, the amount of γ -radiation increasing with increase of atomic weight of the material. The particular disposition used in his first experiments was not suitable for the examination of any soft types of radiation which might have been excited, but in later work he showed, for the first time, that characteristic radiations were excited in the case of silver, tin, barium and cerium. Chadwick, using the balance method of Rutherford and Chadwick, examined whether the β -rays from radium B and radium C excite penetrating γ -rays in different kinds of matter. Definite evidence was obtained that an excited radiation amounting to about 0.5 per cent, of the primary γ -radiation is produced. This method, however, was not suitable for the detection of soft characteristic radiations. These general results have recently been confirmed by Starke, using the β -rays from a strong preparation of mesothorium. In previous papers by Rutherford and the author on the analysis of the γ -rays from radioactive substances, it has been shown that the γ -rays emitted by the different products can be separated into groups differing widely in penetrating power. Some of these radiations appear to be characteristic of the elements by which they are emitted and fall into one or other of the series given by Barkla. On the other hand, some of the groups of rays found do not appear to belong to either series. It was further shown in previous work that when radium C is deposited on nickel a soft radiation is given out which is entirely absorbed by 2 mm. of aluminium. This soft radiation was much more readily absorbed than that emitted by radium B, and for which μ = 40 (cm. -1 ), but it was appreciably harder than the characteristic radiation of nickel. Moreover, when radium C was deposited on silver, little, if any, soft radiation appeared to be emitted. It seemed of importance, therefore, to examine in detail the nature of the radiation excited by the β - and γ -rays from radium B and radium C, and to examine the bearing of the results on the type of radiation emitted by different materials on which radium C is deposited.


In previous papers an account has been given of a new counting method for analysing the groups of α-rays emitted by radioactive substances, and for measuring directly their mean range in air. In the course of these experiments, we showed that the long range groups of α-particles from radium C' are very complex, consisting of at least nine groups, with mean ranges lying between 7·7 and 11·6 cm. of air. As it is believed that the energies of these long range groups are intimately connected with those of the γ-rays from radium C', it has become of great importance to determine the energies of these groups of particles with precision. As, however, the seven groups with ranges between 9·5 and 11·6 cm. differ so little in velocity that they can only be partially resolved in range measurements, it was very difficult in our experiments to determine the mean ranges with accuracy. Moreover, there has been considerable uncertainty as to the precise relation between the range and velocity of such long range particles. A much greater resolving power can be obtained by a direct velocity determination, using a magnet to bend the α-rays into a circle. The great Paris electromagnet has been used in this way by Rosenblum, who photographed the α-ray spectra produced by the well-known focussing method. He has demonstrated the complexity of a number of α-ray groups, and has measured their velocities with an accuracy of at least 1 in 1000.


2018 ◽  
Vol 9 (3) ◽  
pp. 553 ◽  
Author(s):  
Yu-Hsuan LIN

This study examines the relationship between individual altruistic attitudes and the incentives of participating in a climate coalition by using a laboratory experiment. A dominant strategy solution design categorizes players into two roles in the game: critical and non-critical players. The critical players have a weakly dominant strategy of joining and are essential to an effective coalition. On the other hand, the non-critical players have a dominant strategy of not-joining. The theory suggests that strong altruism would lead non-critical players to join a coalition. The experimental evidence shows that coalitions could be enlarged from the self-interest prediction. However, the result indicates that the individual incentives for participation seem to be negatively correlated with altruistic attitudes. The stronger the altruistic tendencies the less likely individuals are to join a coalition.


Author(s):  
E. N. Albert

Silver tetraphenylporphine sulfonate (Ag-TPPS) was synthesized in this laboratory and used as an electron dense stain for elastic tissue (Fig 1). The procedures for the synthesis of tetraphenylporphine sulfonate and the staining method for mature elastic tissue have been described previously.The fine structure of developing elastic tissue was observed in fetal and new born rat aorta using tetraphenylporphine sulfonate, phosphotungstic acid, uranyl acetate and lead citrate. The newly forming elastica consisted of two morphologically distinct components. These were a central amorphous and a peripheral fibrous. The ratio of the central amorphous and the peripheral fibrillar portion changed in favor of the former with increasing age.It was also observed that the staining properties of the two components were entirely different. The peripheral fibrous component stained with uranyl acetate and/or lead citrate while the central amorphous portion demonstrated no affinity for these stains. On the other hand, the central amorphous portion of developing elastic fibers stained vigorously with silver tetraphenylporphine sulfonate, while the fibrillar part did not (compare figs 2, 3, 4). Based upon the above observations it is proposed that developing elastica consists of two components that are morphologically and chemically different.


Author(s):  
Alfredo Feria-Velasco ◽  
Guadalupe Tapia-Arizmendi

The fine structure of the Harderian gland has been described in some animal species (hamster, rabbit, mouse, domestic fowl and albino rats). There are only two reports in the literature dealing on the ultrastructure of rat Harderian gland in adult animals. In one of them the author describes the myoepithelial cells in methacrylate-embbeded tissue, and the other deals with the maturation of the acinar cells and the formation of the secretory droplets. The aim of the present work is to analize the relationships among the acinar cell components and to describe the two types of cells located at the perifery of the acini.


1976 ◽  
Vol 41 (4) ◽  
pp. 523-529 ◽  
Author(s):  
Daniel R. Boone ◽  
Harold M. Friedman

Reading and writing performance was observed in 30 adult aphasic patients to determine whether there was a significant difference when stimuli and manual responses were varied in the written form: cursive versus manuscript. Patients were asked to read aloud 10 words written cursively and 10 words written in manuscript form. They were then asked to write on dictation 10 word responses using cursive writing and 10 words using manuscript writing. Number of words correctly read, number of words correctly written, and number of letters correctly written in the proper sequence were tallied for both cursive and manuscript writing tasks for each patient. Results indicated no significant difference in correct response between cursive and manuscript writing style for these aphasic patients as a group; however, it was noted that individual patients varied widely in their success using one writing form over the other. It appeared that since neither writing form showed better facilitation of performance, the writing style used should be determined according to the individual patient’s own preference and best performance.


2008 ◽  
Vol 1 (2) ◽  
pp. 187-199
Author(s):  
KATHRYN WALLS

According to the ‘Individual Psychology’ of Alfred Adler (1870–1937), Freud's contemporary and rival, everyone seeks superiority. But only those who can adapt their aspirations to meet the needs of others find fulfilment. Children who are rejected or pampered are so desperate for superiority that they fail to develop social feeling, and endanger themselves and society. This article argues that Mahy's realistic novels invite Adlerian interpretation. It examines the character of Hero, the elective mute who is the narrator-protagonist of The Other Side of Silence (1995) , in terms of her experience of rejection. The novel as a whole, it is suggested, stresses the destructiveness of the neurotically driven quest for superiority. Turning to Mahy's supernatural romances, the article considers novels that might seem to resist the Adlerian template. Focusing, in particular, on the young female protagonists of The Haunting (1982) and The Changeover (1984), it points to the ways in which their magical power is utilised for the sake of others. It concludes with the suggestion that the triumph of Mahy's protagonists lies not so much in their generally celebrated ‘empowerment’, as in their transcendence of the goal of superiority for its own sake.


1973 ◽  
Vol 74 (4) ◽  
pp. 769-774 ◽  
Author(s):  
Akira Yokoyama ◽  
Hiroshi Tomogane ◽  
Katuaki Ôta
Keyword(s):  

ABSTRACT A non-steroidal oestrogen antagonist, MER-25, was administered to cycling rats for elucidating the role of oestrogen in the surge of prolactin observed on the afternoon of pro-oestrus (POe). In animals injected with 20 mg of MER-25 intramuscularly on the afternoon (16.30 h) of the first day of dioestrus (D-1), the surge of prolactin was blocked while the level of prolactin on the afternoon of POe of these animals was significantly higher than that of the corresponding controls injected with oil. Ovulation was also blocked in these animals treated with the drug on the afternoon of D-l. On the other hand, treatment on the morning (10.30 h) of the 2nd day of dioestrus failed to prevent not only the surge of prolactin but also ovulation. These observations provide strong evidence for the view that oestrogen is responsible for the surge of prolactin on the afternoon of POe, and that the surge is accompanied by that of LH.


2011 ◽  
Vol 2011 (1) ◽  
pp. 5-28
Author(s):  
Jens Bonnemann

In ethics, when discussing problems of justice and a just social existence one question arises obviously: What is the normal case of the relation between I and you we start from? In moral philosophy, each position includes basic socio-anthropological convictions in that we understand the other, for example, primarily as competitor in the fight for essential resources or as a partner in communication. Thus, it is not the human being as isolated individual, or as specimen of the human species or socialised member of a historical society what needs to be understood. Instead, the individual in its relation to the other or others has been studied in phenomenology and the philosophy of dialogue of the twentieth century. In the following essay I focus on Martin Buber’s and Jean-Paul Sartre’s theories of intersubjectivity which I use in order to explore the meaning of recognition and disrespect for an individual. They offer a valuable contribution to questions of practical philosophy and the socio-philosophical diagnosis of our time.


2019 ◽  
Author(s):  
Shane Timmons

Encouraging consumers to switch to lower-rate mortgages is important both for the individual consumer’s finances and for functioning competitive markets, but switching rates are low. Given the complexity of mortgages, one potential regulatory intervention that may increase switching rates is to provide independent advice on how to select good mortgage products and how to navigate the switching process. Working with a government consumer protection agency, we conducted an experiment with mortgage-holders to test whether such advice alters perceptions of switching. The experiment tested how (i) the attributes of the offer, (ii) perceptions about the switching process, (iii) individual feelings of competence and (iv) comprehension of the product affect willingness to switch to better offers, both before and after reading the official advice. The advice made consumers more sensitive to interest rate decreases, especially at longer terms. It also increased consumers’ confidence in their ability to select good offers. Overall, the findings imply that advice from policymakers can change perceptions and increase switching rates. Moreover, the experiment demonstrates how lab studies can contribute to behaviourally-informed policy development.


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