scholarly journals Second Report on a Test of McDougall's Lamarckian Experiment on the Training of Rats

1942 ◽  
Vol 19 (2) ◽  
pp. 158-167
Author(s):  
W. E. AGAR ◽  
F. H. DRUMMOND ◽  
O. W. TIEGS
Keyword(s):  
Control Line ◽  
Progressive Decrease ◽  
Progressive Change ◽  
Lamarckian Inheritance ◽  
Rate Of Learning ◽  
Periodic Fluctuations ◽  
Successive Generations ◽  
Made In

The experiment, devised to test McDougall's claim that the effect of training in rats is inherited, has been carried out for twenty generations. In addition to the trained line, a control line has been maintained parallel with it, from which a number of rats have been trained in each generation, but not used for breeding. For each generation of the trained line there is therefore a corresponding group of trained control rats for comparison, differing from the rats of the trained line only in that they have no trained ancestry. During the first fifteen or sixteen generations there was a progressive, though irregular decline in the number of errors made in each generation in both lines. In generation 18 both lines showed a marked increase in the number of errors made, with fluctuations in subsequent generations running closely parallel in the two lines. This parallelism of periodic fluctuations in rate of learning in the two lines makes it impossible to attribute a progressive change in the trained line, when it happens to be in the direction of decreasing number of errors, to the inherited effects of ancestral training. Our experiment is being continued, and therefore our conclusions must be regarded as tentative only. The results of the experiment up to the present, together with those of Crew's experiment, show however, that the progressive decrease in the number of errors in successive generations of McDougall's experiment, in which no control line was maintained, cannot be held to have established the operation of Lamarckian inheritance.

Third Report on a Test of Mcdougall'S Lamarckian Experiment on the Training of Rats

1948 ◽  
Vol 25 (2) ◽  
pp. 103-122
Author(s):  
W. E. AGAR ◽  
F. H. DRUMMOND ◽  
O. W. TIEGS
Keyword(s):  
Body Size ◽  
Genetic Differences ◽  
Colour Pattern ◽  
Control Line ◽  
Present Position ◽  
Progressive Decline ◽  
Lamarckian Inheritance ◽  
Successive Generations ◽  
And Control

This experiment, to test McDougall's conclusion that the effects of training are inherited, has now been carried on for thirty-six generations, involving the training of 2827 rats. The present position of the problem raised by McDougall may be summarized as follows: Neither our own experiment, nor that of Crew, shows any evidence of increasing facility in learning attributable to trained ancestry. McDougall's claim that the progressive decline in the number of errors which he found in successive generations of trained rats is an example of Lamarckian inheritance cannot be maintained in face of the facts (a) that he did not keep a control line, (b) that we have found a progressive decline in our trained line similar to McDougall's, but this was paralleled by the control line; moreover, after about twenty-eight generations, the number of errors progressively increased again in both lines. McDougall's further argument from the change from a zero-day preference for the bright gangway in earlier generations to a preference for the dim gangway in later generations is invalid; it is shown, from his own figures, to be capable of a different explanation. The discovery of genetic differences in colour pattern and body size between our trained and control lines, presumably due to mutations, emphasizes the difficulty of interpreting genetic differences in facility of learning, even if they should occur, as due to the Lamarckian factor. The experiment is being continued.

scholarly journals On the eclipses of agathocles, thales and xerxes

1854 ◽  
Vol 6 ◽  
pp. 277-281 ◽  
Keyword(s):  
Great Improvement ◽  
Lunar Theory ◽  
Progressive Change ◽  
Change In The Mean ◽  
The Mean ◽  
Made In

The author, after remarking that the calculations of distant eclipses made in the last century possess little value, proceeds to give the successive steps of improvement in the lunar theory as applicable to the computation of eclipses, and especially in the motion of the moon’s node. The first great improvement was the introduction by Laplace of terms expressing a progressive change in the mean secular motions. With Bürg’s tables, in which these changes were introduced, or with the same elements, Mr. Francis Baily and Mr. Ottmanns computed many eclipses in the search for that usually called the eclipse of Thales; and both these astronomers fixed upon the eclipse of b. c. 610, September 30, as the only one which could be reconciled with the account of Herodotus.

scholarly journals Lymphomas associated with a tolerant lymphocytic choriomeningitis virus infection in mice

1980 ◽  
Vol 14 (2) ◽  
pp. 117-121 ◽  
Author(s):  
H. H. Skinner ◽  
E. H. Knight ◽  
M. C. Lancaster
Keyword(s):  
Virus Infection ◽  
Mouse Strain ◽  
Fold Increase ◽  
Lymphocytic Choriomeningitis ◽  
Lymphocytic Choriomeningitis Virus ◽  
Breeding Stock ◽  
Viral Oncogene ◽  
Lymphocytic Choriomeningitis Virus Infection ◽  
Successive Generations ◽  
Made In

On each of 2 occasions when a tolerant lymphocytic choriomeningitis (LCM) virus infection was introduced experimentally by a natural route into breeding stock of the Pirbright P(SD) mouse strain, and a comparison made with genetically identical controls, there was in successive generations an overall 15-fold increase in the incidence of lymphomas. Most of these were recognized clinically after the age of 16 months. The same observation was made in mice of the P(H) strain from which the P(SD) strain had been surgically derived. The finding is interpreted as the activation of an endogenous viral oncogene by the LCM infection. It was concurrently observed that the incidence of mammary tumours in the P(H) strain mice before the age of 16 months was markedly lower in the animals infected with LCM.

scholarly journals Study of the Irradiation Damage in Simple Crystals by Channeling

2019 ◽  
Vol 7 ◽  
pp. 163
Author(s):  
M. Kokkoris ◽  
H. Huber ◽  
S. Kossionides ◽  
T. Paradellis ◽  
Ch. Zarkadas ◽  
...  
Keyword(s):  
Heavy Ions ◽  
Maximum Dose ◽  
High Energy ◽  
Irradiation Damage ◽  
Progressive Change ◽  
The Past ◽  
Random Direction ◽  
The Impact ◽  
Made In

Several experiments have been carried out in the past in order to examine the impact of medium and heavy ions in crystals in the MeV range, which is of particular interest in high energy implantations. In the present work, the gradual amorphisation of simple crystals such as Si (100), Ge (100) and W (100) when irradiated with 18 MeV 1 6 0 in a random direction is being studied using the progressive change of channeling parameters, up to a maximum dose of approximately 1Ί01 6 par tides/en*2. The results are compared to the ones present in literature and an attempt is made in order to explain the peculiarities of the experimental spectra.

scholarly journals The Shell of V603 Aql and the Early Stages of the Nova Event

1974 ◽  
Vol 3 ◽  
pp. 509-532 ◽  
Author(s):  
H. Weaver
Keyword(s):  
Visible Light ◽  
Light Curve ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Transition Stage ◽  
Spectroscopic Observations ◽  
Early Stages ◽  
Periodic Fluctuations ◽  
Made In

Nova V603 Aql 1918 was uniquely suited for studies of the structure of its shell because of the very favorable orientation of the shell in space. Additionally, almost by chance, spectroscopic observations were made in such a way that they permitted derivation of a three dimensional model of the shell.V603 Aql, as we see from its light curve (Figure 1), was a typical fast nova which showed strong periodic fluctuations in light during the transition stage. The period of fluctuation was approximately 10 days, during which time the visible light changed by roughly 50%.

Proportion of cross-bred and selfed seed obtained from successive generations of winter bean (Vicia faba L.) crops

1987 ◽  
Vol 108 (1) ◽  
pp. 103-108 ◽  
Author(s):  
D. A. Bond ◽  
M. Pope
Keyword(s):  
Regulatory Mechanism ◽  
Selfed Seed ◽  
The Third ◽  
Term Change ◽  
Vicia Faba L ◽  
Successive Generations ◽  
Field Beans ◽  
Made In

SummaryThe proportions of cross-bred and selfed seed were estimated in up to four consecutive generations of Throws MS winter beans on three farms where farm-saved seed was regularly used.Within one stock the percentage of cross-breds rose a significant amount from 31 to 46, whilst in another stock no change was detected over four consecutive generations. On the third farm a change of stock mid-way through the period of the survey was associated with a highly significant increase in proportion of cross-breds.In general a rise in outcrossing was not followed by a significant fall as would be expected if cross-breds have a greater tendency than inbreds to self pollinate, but the possible role of a regulatory mechanism is discussed as are implications of the range in outcrossing within stocks for variety trials and commercial production of winter beans.Estimates of outcrossing frequency made in two crops in 1983 were slightly lower than some obtained in 1974–6 but no lower than those reported in 1951 thus providing no evidence of any long-term change in levels of natural cross-breeding in field beans in England.

scholarly journals Agitating for Change: Theatre and a Feminist ‘Network of Resistance’

2016 ◽  
Vol 41 (1) ◽  
pp. 5-20 ◽  
Author(s):  
ELAINE ASTON
Keyword(s):  
Primary Concern ◽  
The West ◽  
Progressive Change ◽  
The Uk ◽  
Made In

Focusing on the UK, where feminism is gaining momentum through multiple sites of activist dissent from a neoliberal hegemony, my primary concern in this article is to understand how, given this renewal of feminist energies, theatre might be able to play its part in agitating for change. Inspired by Chantal Mouffe's compelling description of a ‘network of resistance’, as a possible way forward I conceive of theatre politically as a series of heterogeneously formed sites of oppositional and affirmative activity, each linked into articulating dissent from neoliberalism and the desire for socially progressive change. This provides the critical framework for my engagement with three radically diverse performances ranging from new playwriting (Lucy Kirkwood'sNSFW), through the flash mob (Eve Ensler's One Billion Rising campaign), to the West End musicalMade in Dagenham.

scholarly journals RNA-guided gene drives can efficiently and reversibly bias inheritance in wild yeast

2015 ◽  
Author(s):  
James E DiCarlo ◽  
Alejandro Chavez ◽  
Sven L Dietz ◽  
Kevin M Esvelt ◽  
George M Church
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Drive ◽  
Wild Type ◽  
Wild Populations ◽  
Yeast Saccharomyces Cerevisiae ◽  
Wild Yeast ◽  
Successive Generations ◽  
Gene Drives ◽  
General Method ◽  
Made In

Inheritance-biasing “gene drives” may be capable of spreading genomic alterations made in laboratory organisms through wild populations. We previously considered the potential for RNA-guided gene drives based on the versatile CRISPR/Cas9 genome editing system to serve as a general method of altering populations. Here we report molecularly contained gene drive constructs in the yeast Saccharomyces cerevisiae that are typically copied at rates above 99% when mated to wild yeast. We successfully targeted both non-essential and essential genes, showed that the inheritance of an unrelated “cargo” gene could be biased by an adjacent drive, and constructed a drive capable of overwriting and reversing changes made by a previous drive. Our results demonstrate that RNA-guided gene drives are capable of efficiently biasing inheritance when mated to wild-type organisms over successive generations.

Fourth (Final) Report on a Test of McDougall'S Lamarckian Experiment on the Training of Rats

1954 ◽  
Vol 31 (3) ◽  
pp. 307-321
Author(s):  
W. E. AGAR ◽  
F. H. DRUMMOND ◽  
O. W. TIEGS ◽  
M. M. GUNSON
Keyword(s):  
Statistical Analysis ◽  
Control Experiment ◽  
Learning Rate ◽  
Final Report ◽  
Long Duration ◽  
Laboratory Colony ◽  
Steady Improvement ◽  
Lamarckian Inheritance ◽  
Rate Of Learning

This is the final report of an experiment of 20 years' duration, in which we have repeated, in its essentials, the well-known experiment of William McDougall purporting to reveal a Lamarckian inheritance of the effects of training on rats. The test is one involving light discrimination, and McDougall recorded a steady improvement in the rate of learning on a succession of 32 generations; but he omitted to check the results against a properly conducted control. Our experiment confirms McDougall to the extent that we too have obtained long duration trends of improvement in learning-rate (Figs. 2, 3); but we find that the effect is not sustained, and that it is, moreover, shown also by a control experiment, using animals of untrained ancestry. This forbids a Lamarckian interpretation. Statistical analysis of the data indicates that the ‘condition’ of the rat markedly affects its speed of learning, and that progressive changes in learning-rate, over a succession of generations, are in reality correlated with the health of the laboratory colony, which is subject to periods of decline and recovery.

The Main Results of the Excavations at Olbia in the Past Three Decades

2007 ◽  
Author(s):  
S. D. KRYZHITSKIY
Keyword(s):  
Archaic Period ◽  
Fifth Century ◽  
Hellenistic Period ◽  
Third Generation ◽  
The Third ◽  
The Past ◽  
Successive Generations ◽  
The City ◽  
The Temple ◽  
Made In

In the 1790s, the location of Olbia was established, and since 1901 systematic excavations have been made by three successive generations of scholars. The first of these scholars was Pharmakovskiy and his school in 1901–1926. The second scholars to make excavations in Olbia were under the leadership of Slavin, Levi and Karasev. The third generation who took over the excavations from 1972 was headed by Kryzhitskiy from 1972–1995 and Krapivina from 1995. This chapter focuses on the contributions made by the third generation of scholars that made excavations in the Olbia region. The excavations made in this period were governed by three aims: the study of the historico-archaelogical stratigraphy and topography of cultural levels in the various parts of the city including the underwater area beneath the Bug estuary; an emphasis on the least-studied phases of the city's existence, particularly the cultural levels of the archaic period and the early centuries AD; and the rescue and conservation of the coastal portion of the city. The excavations generated important results such as the discovery of the temenos wall, altars, the temple of Apollo Ietros, Hellenistic period citadels and dwellings, and defensive walls belonging to the fifth century. In addition to these excavations and discoveries, the teams headed by Kryzhitskiy and Krapivina made extensive studies on the lower Bug estuary and Olbia's chora.

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