scholarly journals ARE CARCINOGENS RESPONSIBLE FOR THE SUPERIMPOSED NEOPLASTIC CHANGES OCCURRING IN MOUSE TUMOR CELLS?

1955 ◽  
Vol 102 (5) ◽  
pp. 517-544 ◽  
Author(s):  
Keith Dumbell ◽  
Peyton Rous
Keyword(s):  
The Other ◽  
Inhibitory Influence ◽  
Mouse Tumor ◽  
Equal Frequency ◽  
Morphological Findings ◽  
Sequence Of Events ◽  
Pulmonary Cells ◽  
Factor Type ◽  
Milk Factor ◽  
Cancerous Change

Three spontaneous pulmonary adenomas of C mice, morphologically resembling those induced by methylcholanthrene or urethane, were propagated in host after host under conditions such that the neoplastic cells were directly exposed, while proliferating, to one or the other of these agents. The successive periods of test lasted for more than a year in some instances, the total exposure to the carcinogens far exceeding that required to change normal pulmonary cells into adenoma cells. One of the adenomas remained unaltered, and the others underwent cancerous changes; but these took place with equal frequency in the control growths, and their occurrence was neither hastened nor delayed by the carcinogens. Two polymorphous mammary carcinomas of "milk-factor" type, with the characteristic tendency to form acini and tubules, were exposed to methylcholanthrene in the same way as the pulmonary adenomas and for periods quite as long. Their cells continued to differentiate, and in other respects underwent no significant change. Urethane had no influence on the rate of growth of the adenomas exposed to it; methylcholanthrene, on the other hand, markedly retarded the enlargement both of them and of the mammary tumors. Its inhibitory influence was not passed on from cell to cell however; when freed of the carcinogen by further transplantation, the retarded tumors grew as fast as the controls. Furthermore the retardation caused no evident delay in the occurrence of cancerous changes in the adenomas. One of the adenomas was maintained in twelve parallel lines while under test and new tumors arose in nine of them, the earliest appearing more than fifteen months after initial transfer of the growth. Always it was an adenoma solidum, this appearing almost concurrently in eight of the nine lines. In six of them it was soon followed by carcinomas, the sequence of events and the morphological findings both indicating that they had derived from it. Individually the cancers were widely various, but they were similar on the whole from line to line. Carcinomas of a wholly different aspect arose from the other adenoma undergoing cancerous change, and they were not preceded by adenoma solidum. In both instances the character of the superimposed neoplastic alterations seemed to have been determined by some inherent trait of the adenoma concerned.

Two Non-senses of “Probability”

2021 ◽  
pp. 47-76
Author(s):  
Wayne C. Myrvold
Keyword(s):  
Relative Frequency ◽  
The Other ◽  
Objective Probability ◽  
Sequence Of Events ◽  
Principle Of Indifference ◽  
Long Run ◽  
Eighteenth And Nineteenth Centuries

This chapter engages in some ground-clearing. Two concepts have been proposed to play the role of objective probability. One is associated with the idea that probability involves mere counting of possibilities (often wrongly attributed to Laplace). The other is frequentism, the idea that probability can be defined as long-run relative frequency in some actual or hypothetical sequence of events. Associated with the idea that probability is merely a matter of counting of possibilities is a temptation to believe that there is a principle, called the Principle of Indifference, which can generate probabilities out of ignorance. In this chapter the reasons that neither of these approaches can achieve its goal are rehearsed, with reference to historical discussions in the eighteenth and nineteenth centuries. It includes some of the prehistory of discussions of what has come to be known, misleadingly, as Bertrand’s paradox.

The Rise of the Muslim Brotherhood and the Potential for Violent Escalation

2020 ◽  
pp. 37-78
Author(s):  
Ioana Emy Matesan
Keyword(s):  
Muslim Brotherhood ◽  
Early History ◽  
The Other ◽  
Religious Movement ◽  
Dual Effect ◽  
Sequence Of Events ◽  
History Of ◽  
The Muslim Brotherhood ◽  
The One ◽  
Gamal Abdel Nasser

This chapter revisits the early history of the Muslim Brotherhood to understand why an organization that started out as a nonviolent religious movement came to be associated with violence. Many blame this on the harsh repression under President Gamal Abdel Nasser. However, the analysis shows that the drift toward violence started much earlier. Reconstructing the sequence of events between 1936 and 1948, the chapter reveals that what initially politicized the Brotherhood was the presence of British troops in Egypt and Palestine. The formation of an armed wing led to competition over authority within the group, which incentivized violent escalation. The chapter then focuses on the period between 1954 and 1970 and shows that repression had a dual effect. On the one hand, it inspired new jihadi interpretations, which were particularly appealing to younger members. On the other hand, the prisons were also the backdrop against which the Brotherhood became convinced that violence was futile.

The grammaticalization of SIC

2021 ◽  
pp. 350-369
Author(s):  
Verner Egerland
Keyword(s):  
Old French ◽  
The Other ◽  
Functional Elements ◽  
Subsequent Work ◽  
The Third ◽  
Sequence Of Events

The Old Romance continuations of Latin sic, such as Old French si and Old Italian sì, involve four different functions, all of which are referred to here as sic. The first one, which is closest to the original Latin usage, is that of a lexical adverbial, while the other three are functional elements introducing main clauses: the second sic follows elements preposed to the verb, the third one introduces clauses in a narrative sequence of events, while the fourth usage of sic has been described as a ‘weak consequential’ (Salvi 2002) . In this article, it is shown that these instantiations of sic in Old Romance, and in particular the third one, are parallel to the grammaticalized usages of svá in Modern Scandinavian. Furthermore, it is argued that the distribution of these functional elements in Old Romance, here represented by French and Italian, as well as Modern Scandinavian, represented by Swedish, can be successfully accounted for in a theory of syntax that incorporates certain notions of ‘narrative’, building on intuitions originating in Labov (1972) and subsequent work.

Orthogonal Fractional Factorial Plans

1980 ◽  
Vol 29 (3-4) ◽  
pp. 143-160 ◽  
Author(s):  
Rahul Mukerjee
Keyword(s):  
Broad Class ◽  
Existence Results ◽  
Fractional Factorial ◽  
The Other ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Equal Frequency ◽  
Other Hand ◽  
Necessary And Sufficient ◽  
Generally True

This paper shows that the criterion of proportional frequency for (unblocked) orthogonal fractional factorial plans, as suggested by some previous authors, is not generally true. On the other hand, the criterion of equal frequency has been established as a necessary and sufficient condition in the general case. Some other properties of orthogonal fractional factorial plans have been investigated. A necessary and sufficient condition for designs involving two or more blocks has also been presented. A broad class of non-existence results follow.

Tissue-specific concentration changes of estrone and estradiol during spontaneous and ACTH-induced parturition in sheep

1987 ◽  
Vol 65 (2) ◽  
pp. 130-135 ◽  
Author(s):  
S. G. A. Power ◽  
J. R. G. Challis
Keyword(s):  
Normal Pregnancy ◽  
Progressive Increase ◽  
The Other ◽  
Fetal Membranes ◽  
Tissue Specific ◽  
Uterine Contractions ◽  
Sequence Of Events ◽  
Estrogen Production ◽  
Concentration Changes ◽  
The Mean

Changes in estrogen production are considered important in the sequence of events leading to parturition. We sought tissue-specific changes in the concentration of unconjugated estrone (E1) and estradiol (E2) in intrauterine fetal (amnion, chorion) and maternal (endometrium, myometrium) tissues during normal pregnancy, labour, and ACTH-induced labour in sheep. The mean concentrations of E1 and E2 in the fetal membranes were higher than in endometrium and myometrium. In amnion there were no consistent changes in estrone concentrations with gestation, although estradiol concentrations increased between day 130 and term. In the endometrium there were increases in both estrone and estradiol between day 100 and term, whereas in the myometrium increases in the concentrations of E1 and E2 occurred between days 130–135 and term. Animals showing a labourlike pattern of uterine contractions after intrafetal ACTH administration did not show significant differences in estrone or estradiol concentrations in amnion, chorion, or endometrium compared with saline-infused controls. However, there was a progressive increase in the concentration of estrone and estradiol in the myometrium during ACTH-induced labour. We conclude that changes in the concentrations of estrone and estradiol in intrauterine tissues vary between the tissues studied and the two estrogens. In general, estrogen concentrations increased towards term, but this trend was more marked in the maternal than fetal tissues. The changes in estrone concentrations in myometrium, but not in the other tissues, were replicated during ACTH-induced labour. Our results would be compatible with the suggestion that tissue-specific changes in estrogen concentrations may contribute to the local intrauterine steroid milieu during pregnancy and at term.

scholarly journals Holes in the Solar Corona

1975 ◽  
Vol 68 ◽  
pp. 19-21
Author(s):  
W. M. Glencross
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Solar Corona ◽  
Field Component ◽  
Solar Surface ◽  
Field Direction ◽  
The Other ◽  
Flux Tubes ◽  
Sequence Of Events

SummaryBabcock (1961) outlined the sequence of events which takes place in the Sun's atmosphere during a solar cycle. Magnetic field loops, having preferred directions, emerge from the solar surface and thereafter merge with neighbouring loops to produce more extended structures. Although flux tubes emerge with a strong E-W field component, having the field direction reversed from one side of the equator to the other, there is a tendency for the longer loops produced by merging to have a significant N-S alignment (Hansen et al., 1972).

Influence of adenosine triphosphate on the isolated perfused mesenteric artery of the rabbit

1983 ◽  
Vol 61 (11) ◽  
pp. 1409-1417 ◽  
Author(s):  
V. S. R. Krishnamurty ◽  
P. J. Kadowitz
Keyword(s):  
Adenosine Triphosphate ◽  
Mesenteric Arteries ◽  
The Other ◽  
Receptor Blocker ◽  
Medium Size ◽  
Inhibitory Influence ◽  
Vasodilator Response ◽  
Other Hand ◽  
Vasoconstrictor Response ◽  
Dose Dependent

The vascular effects of adenosine triphosphate (ATP) were examined in the isolated perfused mesenteric arteries of the rabbit. Bolus injections of ATP (1 × 10−8 to 10−6 mol) induced a dose-dependent vasoconstrictor response at resting perfusion pressure, while continuous perfusion with ATP briefly elicited a vasoconstrictor response which was not maintained. Perfusion with phentolamine (2.65 × 10−6 M, an α-adrenergic receptor blocker), indomethacin (8.37 × 10−6 M, an inhibitor of cyclooxygenase), atropine (1 × 10−7 M, a muscarinic receptor blocker), and hydralazine (2 × 10−4 M, a vascular smooth muscle inhibitor) for a period of 1 h had no effect on vasoconstrictor responses to ATP. However, pretreatment with reserpine (2 mg∙kg−1∙day−1 for 2 days), an agent which depletes catecholamines, potentiated responses to ATP. On the other hand, when vascular tone was increased with an isoosmotic 60 mM K+ depolarizing Krebs bicarbonate solution, bolus injections of ATP elicited a prominent dose-dependent vasoconstriction followed by a prominent vasodilation. The degree of vasodilation but not of vasoconstriction elicited by ATP was greater in small terminal arteries with branches (<0.5 mm outside diameter (o.d.)) than in the medium size arteries (≤1 mm o.d.) without terminal branches. Both the vasoconstrictor and vasodilator responses were unaffected by a perfusion with atropine, indomethacin, or eicosatetraynoic acid (ETYA, 1 × 10−4 M) for 1 – 2 h. The vasoconstrictor responses were potentiated while the vasodilator responses were inhibited significantly by perfusion with propranolol (3 × 10−6 M) and phentolamine (2.65 × 10−6 M) together for 1 h or by pretreatment with reserpine followed by cold storage at 2 °C for 24 h. Perfusion with 8-phenyltheophylline (4 × 10−6 M (8-PT), an adenosine receptor blocker) for 1 h significantly inhibited by the vasodilator responses to bolus injections of adenosine but not to ATP. Further, ATP but not adenosine elicited a much more prominent vasodilator response on norepinephrine (NE) induced tone than on 60 mM K+. These studies suggest that ATP may induce vasoconstriction independent of activation of α-adrenergic or muscarinic receptors or enhanced synthesis of prostaglandins. This vasoconstriction is resistant to the inhibitory influence of hydralazine. On the other hand, the vasodilator response to ATP may be mediated through its interactions with released or circulating norepinephrine.

Douglasdeweya: A new genus, with a new species and a new combination (Triticeae: Poaceae)

2005 ◽  
Vol 83 (4) ◽  
pp. 413-419 ◽  
Author(s):  
C Yen ◽  
J L Yang ◽  
B R Baum
Keyword(s):  
New Species ◽  
New Genus ◽  
The Other ◽  
New Combination ◽  
Outstanding Scientist ◽  
Narrow Endemic ◽  
Morphological Findings ◽  
A New Species

The new genus Douglasdeweya C. Yen, J.L. Yang & B.R. Baum is based on results from cytogenetical and morphological findings — PPStSt genome — and is segregated from the genus Pseudoroegneria — StSt and StStStSt genome. Several characters, such as the erect spike with very finely spinulose pubescence along the two main angles of the rachis, and glumes and lemmas with a very strong midrib forming a keel-like structure distinguish Douglasdeweya from Pseudoroegneria, which has a rather lax spike, a rachis that is glabrous along the two main angles, and glumes and lemmas without a keel-like structure. The genus is named in memory of Dr. Douglas R. Dewey, an outstanding scientist who worked on the biosystematics of the perennial Triticeae. Two species are described, one of which is new, Douglasdeweya wangyii C. Yen, J.L. Yang & B. R. Baum and the other a new combination Douglasdeweya deweyi (K.B. Jensen, S.L. Hatch, & J.K. Wipff) C. Yen, J.L. Yang, & B.R. Baum. A key to the two species is provided, together with details on their taxonomy, nomenclature, distribution, and cytology.Key words: PPStSt genome, narrow endemic.

Regenerative studies on the detached leaves of Echeveria elegans. Regeneration and growth in leaves

1973 ◽  
Vol 51 (2) ◽  
pp. 451-456 ◽  
Author(s):  
M. V. S. Raju ◽  
James E. Hines
Keyword(s):  
Metabolic Activity ◽  
Dry Weight ◽  
The Other ◽  
Inhibitory Influence ◽  
Other Hand ◽  
Detached Leaves

Detached leaves of Echeveria elegans Bgr. produce both roots and shoots. However, when their bases are severed, they tend to produce only roots. It was observed that roots had to be present on detached leaves, bases removed or not, in order to have an increase in size and also in dry weight. The growth in size was found to be due mainly to enlargement of cells, and the increase in dry weight was presumably due to maintenance of normal metabolic activity in the detached leaves. Thus detached leaves of E. elegans have a greater potential for growth than is normally realized by the leaves that are mature and still attached to the parent axis. The vigorously growing shoots seem to have an inhibitory influence on growth in the detached leaves. Roots on detached leaves, on the other hand, seem to play an important role not only in the delaying of senescence but also in reducing the inhibitory influence of shoots. Roots alone appeared to bring about "uncontrolled" enlargement of cells and consequently lesions were formed on the leaves, which finally died off. Thus growth, regeneration, and senescence in the detached leaves appear to be correlative phenomena.

Randomness

2018 ◽  
Author(s):  
William A. Dembski
Keyword(s):  
Computer Simulation ◽  
Probability Distribution ◽  
Equilibrium State ◽  
Random Sample ◽  
Random Number Generator ◽  
The Other ◽  
Number Generator ◽  
Fluid Forces ◽  
Sequence Of Events ◽  
To Come

The fundamental intuition underlying randomness is the absence of order or pattern. To cash out this intuition philosophers and scientists employ five approaches to randomness. (1) Randomness as the output of a chance process. Thus an event is random if it is the output of a chance process. Moreover, a sequence of events constitutes a random sample if all events in the sequence derive from a single chance process and no event in the sequence is influenced by the others. (2) Randomness as mimicking chance. Statisticians frequently wish to obtain a random sample (in the sense of (1)) according to some specified probability distribution. Unfortunately, a chance process corresponding to this probability distribution may be hard to come by. In this case a statistician may employ a computer simulation to mimic the desired chance process (for example, a random number generator). Randomness qua mimicking chance is also known as pseudo-randomness. (3) Randomness via mixing. Consider the following situation: particles are concentrated in some corner of a fluid; forces act on the fluid so that eventually the particles become thoroughly mixed throughout the fluid, reaching an equilibrium state. Here randomness is identified with the equilibrium state reached via mixing. (4) Randomness as a measure of computational complexity. Computers are ideally suited for generating bit strings. The length of the shortest program that generates a given bit string, as well as the minimum time it takes for a program to generate the string, both assign measures of complexity to the strings. The higher the complexity, the more random the string. (5) Randomness as pattern-breaking. Given a specified collection of patterns, an object is random if it breaks all the patterns in the collection. If, on the other hand, it fits at least one of the patterns in the collection, then it fails to be random.

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