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1.
A. E. L. Davis 《Archive for History of Exact Sciences》2003,57(5):355-393
Epitome V (1621), and consisted of matching an element of area to an element of time, where each was mathematically determined. His
treatment of the area depended solely on the geometry of Euclid's Elements, involving only straight-line and circle propositions – so we have to account for his deliberate avoidance of the sophisticated
conic-geometry associated with Apollonius. We show also how his proof could have been made watertight according to modern
standards, using methods that lay entirely within his power.
The greatest innovation, however, occurred in Kepler's fresh formulation of the measure of time. We trace this concept in
relation to early astronomy and conclude that Kepler's treatment unexpectedly entailed the assumption that time varied nonuniformly;
meanwhile, a geometrical measure provided the independent variable. Even more surprisingly, this approach turns out to be
entirely sound when assessed in present-day terms.
Kepler himself attributed the cause of the motion of a single planet around the Sun to a set of `physical' suppositions which
represented his religious as well as his Copernican convictions; and we have pared to a minimum – down to four – the number
he actually required to achieve this.
In the Appendix we use modern mathematics to emphasize the simplicity, both geometrical and kinematical, that objectively
characterizes the Sun-focused ellipse as an orbit. Meanwhile we highlight the subjective simplicity of Kepler's own techniques
(most of them extremely traditional, some newly created). These two approaches complement each other to account for his success.
(Received April 19, 2002)
Published online April 2, 2003
Communicated by N. M. Swerdlow 相似文献
2.
Einstein’s quantum theory of the monatomic ideal gas: non-statistical arguments for a new statistics
In this article, we analyze the third of three papers, in which Einstein presented his quantum theory of the ideal gas of
1924–1925. Although it failed to attract the attention of Einstein’s contemporaries and although also today very few commentators
refer to it, we argue for its significance in the context of Einstein’s quantum researches. It contains an attempt to extend
and exhaust the characterization of the monatomic ideal gas without appealing to combinatorics. Its ambiguities illustrate
Einstein’s confusion with his initial success in extending Bose’s results and in realizing the consequences of what later
came to be called Bose–Einstein statistics. We discuss Einstein’s motivation for writing a non-combinatorial paper, partly
in response to criticism by his friend Ehrenfest, and we paraphrase its content. Its arguments are based on Einstein’s belief
in the complete analogy between the thermodynamics of light quanta and of material particles and invoke considerations of
adiabatic transformations as well as of dimensional analysis. These techniques were well known to Einstein from earlier work
on Wien’s displacement law, Planck’s radiation theory and the specific heat of solids. We also investigate the possible role
of Ehrenfest in the gestation of the theory. 相似文献
3.
Endogenous electrical fields (EFs) at corneal and skin wounds send a powerful signal that directs cell migration during wound
healing. This signal therefore may serve as a fundamental regulator directing cell polarization and migration. Very little
is known of the intracellular and molecular mechanisms that mediate EF-induced cell polarization and migration. Here, we report
that Chinese hamster ovary (CHO) cells show robust directional polarization and migration in a physiological EF (0.3–1 V/cm)
in both dissociated cell culture and monolayer culture. An EF of 0.6 V/cm completely abolished cell migration into wounds
in monolayer culture. An EF of higher strength (≥1 V/cm) is an overriding guidance cue for cell migration. Application of
EF induced quick phosphorylation of glycogen synthase kinase 3β (GSK-3β) which reached a peak as early as 3 min in an EF.
Inhibition of protein kinase C (PKC) significantly reduced EF-induced directedness of cell migration initially (in 1–2 h).
Inhibition of GSK-3β completely abolished EF-induced GA polarization and significantly inhibited the directional cell migration,
but at a later time (2–3 h in an EF). Those results suggest that GSK-3β is essential for physiological EF-induced Golgi apparatus
(GA) polarization and optimal electrotactic cell migration. 相似文献
4.
H. Hamshaw Thomas Sc.D. F.R.S. 《Annals of science》2013,70(4):325-341
Sous la Révolution, la conjoncture politique et militaire et l'échec de la poudre de muriate (chlorate) devaient conduire la France à privilégier la rationalisation des procédés de fabrication pour tenter d'accroître la portée des armes. En 1796, la poudre ronde de J. P. Champy (1744–1816), successeur de Lavoisier à la tête du service des Poudres et salpêtres, parut approcher de la poudre idéale: pour un prix de revient réduit, elle offrait une puissance suffisante et une sécurité optimale de fabrication et d'emploi. Malgré l'avis des experts scientifiques et militaires, sa production cessa pourtant à la suite d'un blocage politico-administratif. A la fin de l'Empire, J. S. Champy (1778–1845), perfectionna le procédé de son père pour en faire le premier système de production mécanisé, dont l'introduction devait modifier l'organisation du travail et la configuration des poudreries créées sous la Restauration. Le succès du système conduisit paradoxalement à son échec après une décennie de production qui resta toujours expérimentale: la poudre ronde remettait en cause les techniques métallurgiques en faisant éclater les canons. La publication inédite du premier rapport d'expertise de ce procédé (1813) fournit l'occasion de suivre les origines et l'évolution d'un système qui annonce la mécanisation de l'industrie poudrière au XIXe siècle, tout en se présentant clairement comme l'aboutissement des procédés révolutionnaires de l'an II. Elle permet aussi de s'interroger sur les critères et le statut de l'expertise, au moment même où l'analyse chimique de la poudre commence avec Proust, Gay-Lussac et Brianchon. 相似文献
5.
Bill Jenkins 《Annals of science》2016,73(4):425-441
The duck-billed platypus, or Ornithorhynchus, was the subject of an intense debate among natural historians in the late eighteenth and early nineteenth centuries. Its paradoxical mixture of mammalian, avian and reptilian characteristics made it something of a taxonomic conundrum. In the early 1820s Robert Jameson (1774–1854), the professor of natural history at the University of Edinburgh and the curator of the University's natural history museum, was able to acquire three valuable specimens of this species. He passed one of these on to the anatomist Robert Knox (1791–1862), who dissected the animal and presented his results in a series of papers to the Wernerian Natural History Society, which later published them in its Memoirs. This paper takes Jameson's platypus as a case study on how natural history specimens were used to create and contest knowledge of the natural world in the early nineteenth century, at a time when interpretations of the relationships between animal taxa were in a state of flux. It shows how Jameson used his possession of this interesting specimen to provide a valuable opportunity for his protégé Knox while also helping to consolidate his own position as a key figure in early nineteenth-century natural history. 相似文献
6.
Beta integrals for several non-integer values of the exponents were calculated by Leonhard Euler in 1730, when he was trying
to find the general term for the factorial function by means of an algebraic expression. Nevertheless, 70 years before, Pietro
Mengoli (1626–1686) had computed such integrals for natural and half-integer exponents in his Geometriae Speciosae Elementa (1659) and Circolo(1672) and displayed the results in triangular tables. In particular, his new arithmetic–algebraic method allowed him to compute
the quadrature of the circle. The aim of this article is to show how Mengoli calculated the values of these integrals as well
as how he analysed the relation between these values and the exponents inside the integrals. This analysis provides new insights
into Mengoli’s view of his algorithmic computation of quadratures. 相似文献
7.
Ronda Bransteitter Courtney Prochnow Xiaojiang S. Chen 《Cellular and molecular life sciences : CMLS》2009,66(19):3137-3147
The apolipoprotein B mRNA-editing enzyme catalytic polypeptide (APOBEC) family of cytidine deaminases has emerged as an intensively
studied field as a result of their important biological functions. These enzymes are involved in lipid metabolism, antibody
diversification, and the inhibition of retrotransposons, retroviruses, and some DNA viruses. The APOBEC proteins function
in these roles by deaminating single-stranded (ss) DNA or RNA. There are two high-resolution crystal structures available
for the APOBEC family, Apo2 and the C-terminal catalytic domain (CD2) of Apo3G or Apo3G-CD2 [Holden et al. (Nature 456:121–124,
2008); Prochnow et al. (Nature 445:447–451, 2007)]. Additionally, the structure of Apo3G-CD2 has also been determined using
NMR [Chen et al. (Nature 452:116–119, 2008); Furukawa et al. (EMBO J 28:440–451, 2009); Harjes et al. (J Mol Biol, 2009)].
A detailed structural analysis of the APOBEC proteins and a comparison to other zinc-coordinating deaminases can facilitate
our understanding of how APOBEC proteins bind nucleic acids, recognize substrates, and form oligomers. Here, we review the
recent development of structural and functional studies that apply to Apo3G as well as the APOBEC deaminase family. 相似文献
8.
The aim of this paper is to provide a comprehensive exposition of the early contributions to the so-called Campbell, Baker,
Hausdorff, Dynkin Theorem during the years 1890–1950. Related works by Schur, Poincaré, Pascal, Campbell, Baker, Hausdorff,
and Dynkin will be investigated and compared. For a full recovery of the original sources, many mathematical details will
also be furnished. In particular, we rediscover and comment on a series of five notable papers by Pascal (Lomb Ist Rend, 1901–1902),
which nowadays are almost forgotten. 相似文献
9.
J. A. RUFFNER 《Archive for History of Exact Sciences》2000,54(4):259-277
Isaac Newton's closest approach to a system of the world in the critical period 1681–84 is provided in a set of untitled
propositions concerning comets. They drastically revise his position maintained against Flamsteed in 1681 and may signal his
adoption of a single comet solution for the appearances of 1680/1. Points of agreement and difference with the key pre-Principia texts of 1684–85 are analysed. He shows substantial control of the phenomena of tails which change very little in mechanical
detail throughout his subsequent work. An emerging theory of gravitation brings planets, their satellites, and comets under
the same laws of motion, yet retains a celestial vortex and includes a singular proposition in lieu of the usual formulation
of Keplers area law. The analysis raises questions on a number of issues of recent Newtonian scholarship ranging from his
achievement following his correspondence with Robert Hooke in 1679 to his veneration of the wisdom of the ancients.
(Received September 7, 1999) 相似文献
10.
Reinhard Siegmund-Schultze 《Archive for History of Exact Sciences》2006,60(5):431-515
The correspondence between Richard von Mises and George Pólya of 1919/20 contains reflections on two well-known articles by
von Mises on the foundations of probability in the Mathematische Zeitschrift of 1919, and one paper from the Physikalische Zeitschrift of 1918. The topics touched on in the correspondence are: the proof of the central limit theorem of probability theory, von
Mises' notion of randomness, and a statistical criterion for integer-valuedness of physical data. The investigation will hint
at both the fruitfulness and the limits of several of von Mises' notions such as ``collective', ``distribution' and ``complex
adjuncts' (characteristic functions) for further developments in probability theory and in ``directional statistics'. By
pointing to the selectiveness of Pólya's criticism, the historical analysis shows the differing expectations of the two men
with respect to the further development of the theory of probability and its applications. The paper thus gives a glimpse
of the provisional state of the theory around 1920, before others such as P. Lévy (1886–1971) and A. N. Kolmogorov (1903–1987)
stepped in and created a new paradigm for probability theory. 相似文献
11.
Anne Merker 《Archive for History of Exact Sciences》2002,56(3):183-238
Résumé L'objet de cet article est d'exposer et d'analyser l'explication proposée par Aristote pour l'arc-en-ciel
dans les Météorologiques, livre III, ch. 2–5. Cette explication présente d'abord un intérêt au regard de l'histoire des sciences exactes, notamment
parce qu'Aristote articule ici très concrètement une approche physique et une approche géométrique de ces phénomènes. Elle
présente ensuite un intérêt et une énigme pour l'exégèse aristotélicienne, dans la mesure où ce texte des Météorologiques adopte l'idée de rayons visuels, plus exactement d'une émission hors de l'œil de quelque chose (laissée indéterminée par Aristote) rendant possible la vision,
alors qu'Aristote avait longuement et rigoureusement combattu toute idée d'une telle émission dans deux traités précédents
(De l'ame, et De la sensation et des sensibles). Elle présente enfin un intérêt philosophique dans la mesure où cette contradiction entre les Météorologiques et ces deux traités antérieurs trouve sa signification dans une exigence portant sur le statut ontologique de l'image spéculaire,
exigence que l'on ne peut séparer de la visée scientifique qui guide Aristote.
Manuscrit re?u le 31 juillet 2001 相似文献
12.
Shaul Katzir 《Archive for History of Exact Sciences》2008,62(5):469-487
In 1918–1919 Walter G. Cady was the first to recognize the significant electrical consequences of the fact that piezoelectric
crystals resonate at very sharp, precise and stable frequencies. Cady was also the first to suggest the employment of these
properties, first as frequency standards and then to control frequencies of electric circuits—an essential component in electronic
technology. Cady’s discovery originated in the course of research on piezoelectric ultrasonic devices for submarine detection
(sonar) during World War I. However, for the discovery Cady had to change his research programme to crystal resonance. This
change followed Cady’s experimental findings and the scientific curiosity that they raised, and was helped by the termination
of the war. Cady’s transition was also a move from “applied” research, aimed at improving a specific technology, to “pure”
research lacking a clear practical aim. This article examines how Cady reached the discovery and his early ideas for its use.
It shows that the discovery was not an instantaneous but a gradual achievement. It further suggests that disinterested “scientific”
research (rather than “engineering” research) was needed in this process, while research aimed at design was required for
the subsequent development of technological devices.
I am very grateful to Chris McGahey for providing me with his research notes taken from Walter Cady’s diaries kept by the
Rhode Island Historical Society, henceforth Diaries. I would like to thank Aharon (Arkee) Eviatar for linguistic comments, Ido Yavetz for our helpful discussion and Jed Buchwald
for his thoughtful comments and editorial work. I thank the Lemelson Center in the National Museum for American History for
a grant that enabled me to study Walter Guyton Cady Papers, 1903–1974, Archives Center, National Museum of American History
(henceforth, ACNMAH) and the staff of the center, especially Alison Oswald, for their help. The following abbreviations are
used: NB—Cady’s research notebooks kept at ACNMAH, AIP - Niels Bohr Library, American Institute of Physics, Cady’s dossier. 相似文献
13.
N.H. de Vaudrey Heathcote B.Sc. 《Annals of science》2013,70(1):13-28
Christian Wilhelm Blomstrand, Professor of Chemistry and Mineralogy at Lund University from 1862 to 1895, was one of the important chemists of the second half of the nineteenth century. His theoretical ideas and experimental accomplishments contributed to advances in several branches of chemistry. Living in Sweden during a transitional period between the older and newer chemistry and being a scientific as well as a political conservative, Blomstrand sought to reconcile Berzelius's dualistic theory with the unitary and type theories. He was opposed to Kekulé's dogma of constant valency, and he strove to establish a sound and complete theory of variable valency. This article briefly outlines Blomstrand's life and considers his best known book, Die Chemie der Jetztzeit (1869), as well as his work on mineralogy, inorganic chemistry (the earth acid elements, heteropoly acids, platinum complexes), and his theoretical views on valency, diazo compounds, and metal-ammines. His so-called ‘chain theory’, as developed and modified by his fellow Scandinavian chemist and close friend, Sophus Mads Jørgensen, was for more than three decades the most popular and successful of the numerous attempts to explain the constitution, properties, and reactions of coordination compounds. 相似文献
14.
15.
Oxidative stress and hypoxia-like injury cause Alzheimer-type molecular abnormalities in central nervous system neurons 总被引:11,自引:0,他引:11
de la Monte SM Neely TR Cannon J Wands JR 《Cellular and molecular life sciences : CMLS》2000,57(10):1471-1481
Neuronal loss and neuritic/cytoskeletal lesions (synaptic disconnection and proliferation of dystrophic neurites) represent
major dementia-associated abnormalities in Alzheimer’s disease (AD). This study examined the role of oxidative stress as a
factor contributing to both the cell death and neuritic degeneration cascades in AD. Primary neuron cultures were treated
with H2O2 (9–90 μM) or desferrioxamine (2–25 μM) for 24 h and then analyzed for viability, mitochondrial mass, mitochondrial function,
and pro-apoptosis and sprouting gene expression. H2O2 treatment causes free-radical injury and desferrioxamine causes hypoxia-type injury without free radical generation. The
H2O2-treated cells exhibited sustained viability but neurite retraction, impaired mitochondrial function, increased levels of
the pro-apoptosis gene product CD95/Fas, reduced expression of N2J1-immunoreactive neuronal thread protein and synaptophysin,
and reduced distribution of mitochondria in neuritic processes. Desferrioxamine treatment resulted in dose-dependent neuronal
loss associated with impaired mitochondrial function, proliferation of neurites, and reduced expression of GAP-43, which has
a role in path-finding during neurite outgrowth. The results suggest that oxidative stress can cause neurodegeneration associated
with enhanced susceptibility to apoptosis due to activation of pro-apoptosis genes, neurite retraction (synaptic disconnection),
and impaired transport of mitochondria to cell processes where they are likely required for synaptic function. In contrast,
hypoxia-type injury causes neuronal loss with proliferation of neurites (sprouting), impaired mitochondrial function, and
reduced expression of molecules required to form and maintain synaptic connections. Since similar abnormalities occur in AD,
both oxidative stress and hypoxic injury can contribute to AD neurodegeneration.
Received 24 May 2000; received after revision 7 July 2000; accepted 27 July 2000 相似文献
16.
17.
Thomas Hawkins 《Archive for History of Exact Sciences》2008,62(6):655-717
The theory of nonnegative matrices is an example of a theory motivated in its origins and development by purely mathematical
concerns that later proved to have a remarkably broad spectrum of applications to such diverse fields as probability theory,
numerical analysis, economics, dynamical programming, and demography. At the heart of the theory is what is usually known
as the Perron–Frobenius Theorem. It was inspired by a theorem of Oskar Perron on positive matrices, usually called Perron’s
Theorem. This paper is primarily concerned with the origins of Perron’s Theorem in his masterful work on ordinary and generalized
continued fractions (1907) and its role in inspiring the remarkable work of Frobenius on nonnegative matrices (1912) that
produced, inter alia, the Perron–Frobenius Theorem. The paper is not at all intended exclusively for readers with expertise
in the theory of nonnegative matrices. Anyone with a basic grounding in linear algebra should be able to read this article
and come away with a good understanding of the Perron–Frobenius Theorem as well as its historical origins. The final section
of the paper considers the first major application of the Perron–Frobenius Theorem, namely, to the theory of Markov chains.
When he introduced the eponymous chains in 1908, Markov adumbrated several key notions and results of the Perron–Frobenius
theory albeit within the much simpler context of stochastic matrices; but it was by means of Frobenius’ 1912 paper that the
linear algebraic foundations of Markov’s theory for nonpositive stochastic matrices were first established by R. Von Mises
and V.I. Romanovsky. 相似文献
18.
H.A.M. Snelders 《Annals of science》2013,70(1):67-80
In the years 1878 and 1879 the American physicist Alfred Marshall Mayer (1836–1897) published his experiments with floating magnets as a didactic illustration of molecular actions and forms. A number of physicists made use of this analogy of molecular structure. For William Thomson they were a mechanical illustration of the kinetic equilibrium of groups of columnar vortices revolving in circles round their common centre of gravity (1878). A number of modifications of Mayer's experiments were described, which gave configurations which were more or less analogous to Mayer's arrangements. It was Joseph John Thomson who, in publications between 1897 and 1907, used Mayer's results to obtain a good deal of insight into the general laws which govern the configuration of the electrons in his atomic model. This article is mainly concerned with Mayer's experiments with floating magnets and their use by a number of physicists. Through his experiments Mayer made a significant, although small, contribution to the theory of atomic structure. 相似文献
19.
20.
Intracellular deposits of aggregated alpha-synuclein are a hallmark of Parkinson’s disease. Protein–protein interactions are
critical in the regulation of cell proteostasis. Synphilin-1 interacts both in vitro and in vivo with alpha-synuclein promoting
its aggregation. We report here that synphilin-1 specifically inhibits the degradation of alpha-synuclein wild-type and its
missense mutants by the 20S proteasome due at least in part by the interaction of the ankyrin and coiled-coil domains of synphilin-1
(amino acids 331–555) with the N-terminal region (amino acids 1–60) of alpha-synuclein. Co-expression of synphilin-1 and alpha-synuclein
wild-type in HeLa and N2A cells produces a specific increase in the half-life of alpha-synuclein, as degradation of unstable
fluorescent reporters is not affected. Synphilin-1 inhibition can be relieved by co-expression of Siah-1 that targets synphilin-1
to degradation. Synphilin-1 inhibition of the proteasomal pathway of degradation of alpha-synuclein may help to understand
the pathophysiological changes occurring in PD and other synucleinopathies. 相似文献