2,165 research outputs found
Axiomatic foundations of quantum mechanics revisited: the case for systems
We present an axiomatization of non-relativistic Quantum Mechanics for a
system with an arbitrary number of components. The interpretation of our system
of axioms is realistic and objective. The EPR paradox and its relation with
realism is discussed in this framework. It is shown that there is no
contradiction between realism and recent experimental results.Comment: submitted to International Journal of Theoretical Physics, uses
Latex, no figure
New remarks on the Cosmological Argument
We present a formal analysis of the Cosmological Argument in its two main
forms: that due to Aquinas, and the revised version of the Kalam Cosmological
Argument more recently advocated by William Lane Craig. We formulate these two
arguments in such a way that each conclusion follows in first-order logic from
the corresponding assumptions. Our analysis shows that the conclusion which
follows for Aquinas is considerably weaker than what his aims demand. With
formalizations that are logically valid in hand, we reinterpret the natural
language versions of the premises and conclusions in terms of concepts of
causality consistent with (and used in) recent work in cosmology done by
physicists. In brief: the Kalam argument commits the fallacy of equivocation in
a way that seems beyond repair; two of the premises adopted by Aquinas seem
dubious when the terms `cause' and `causality' are interpreted in the context
of contemporary empirical science. Thus, while there are no problems with
whether the conclusions follow logically from their assumptions, the Kalam
argument is not viable, and the Aquinas argument does not imply a caused
origination of the universe. The assumptions of the latter are at best less
than obvious relative to recent work in the sciences. We conclude with mention
of a new argument that makes some positive modifications to an alternative
variation on Aquinas by Le Poidevin, which nonetheless seems rather weak.Comment: 12 pages, accepted for publication in International Journal for
Philosophy of Religio
Weitere Untersuchungen über die Athmung der Würmer
WEITERE UNTERSUCHUNGEN ÃœBER DIE ATHMUNG DER WÃœRMER
Details:
Zeitschrift für physiologische Chemie: 1.1877-20.1895
Hoppe-Seyler's Zeitschrift für physiologische Chemie: 21.1895- 112.1921 (-)
Zeitschrift für Physiologische Chemie (14) (a0000)
Weitere Untersuchungen über die Athmung der Würmer (14) (p0318
Exact Philosophy of Space-Time
Starting from Bunge's (1977) scientific ontology, we expose a materialistic
relational theory of space-time, that carries out the program initiated by
Leibniz, and provides a protophysical basis consistent with any rigorous
formulation of General Relativity. Space-time is constructed from general
concepts which are common to any consistent scientific theory and they are
interpreted as emergent properties of the greatest assembly of things, namely,
the world.Comment: 13 pages, 3 figures. Version compatible with the published one. arXiv
admin note: substantial text overlap with arXiv:gr-qc/971006
A bacterial artificial chromosome library for the Australian saltwater crocodile (Crocodylus porosus) and its utilization in gene isolation and genome characterization
Background
Crocodilians (Order Crocodylia) are an ancient vertebrate group of tremendous ecological, social, and evolutionary importance. They are the only extant reptilian members of Archosauria, a monophyletic group that also includes birds, dinosaurs, and pterosaurs. Consequently, crocodilian genomes represent a gateway through which the molecular evolution of avian lineages can be explored. To facilitate comparative genomics within Crocodylia and between crocodilians and other archosaurs, we have constructed a bacterial artificial chromosome (BAC) library for the Australian saltwater crocodile, Crocodylus porosus. This is the first BAC library for a crocodile and only the second BAC resource for a crocodilian. Results
The C. porosus BAC library consists of 101,760 individually archived clones stored in 384-well microtiter plates. Not I digestion of random clones indicates an average insert size of 102 kb. Based on a genome size estimate of 2778 Mb, the library affords 3.7 fold (3.7×) coverage of the C. porosus genome. To investigate the utility of the library in studying sequence distribution, probes derived from CR1a and CR1b, two crocodilian CR1-like retrotransposon subfamilies, were hybridized to C. porosusmacroarrays. The results indicate that there are a minimum of 20,000 CR1a/b elements in C. porosus and that their distribution throughout the genome is decidedly non-random. To demonstrate the utility of the library in gene isolation, we probed the C. porosus macroarrays with an overgo designed from a C-mos (oocyte maturation factor) partial cDNA. A BAC containing C-mos was identified and the C-mos locus was sequenced. Nucleotide and amino acid sequence alignment of the C. porosus C-mos coding sequence with avian and reptilian C-mos orthologs reveals greater sequence similarity between C. porosus and birds (specifically chicken and zebra finch) than between C. porosus and squamates (green anole). Conclusion
We have demonstrated the utility of the Crocodylus porosus BAC library as a tool in genomics research. The BAC library should expedite complete genome sequencing of C. porosus and facilitate detailed analysis of genome evolution within Crocodylia and between crocodilians and diverse amniote lineages including birds, mammals, and other non-avian reptiles
Parmenides reloaded
I argue for a four dimensional, non-dynamical view of space-time, where
becoming is not an intrinsic property of reality. This view has many features
in common with the Parmenidean conception of the universe. I discuss some
recent objections to this position and I offer a comparison of the Parmenidean
space-time with an interpretation of Heraclitus' thought that presents no major
antagonism.Comment: 11 pages, accepted for publication in Foundations of Scienc
Rapid South Atlantic spreading changes and coeval vertical motion in surrounding continents: Evidence for temporal changes of pressure-driven upper mantle flow
International audienceThe South Atlantic region displays (1) a topographic gradient across the basin, with Africa elevated relative to South America, (2) a bimodal spreading history with fast spreading rates in Late Cretaceous and Eo-Oligocene, and (3) episodic regional uplift events in the adjacent continents concentrated in Late Cretaceous and Oligocene. Here we show that these observations can be linked by dynamic processes within Earth's mantle, through temporal changes in asthenosphere flow beneath the region. The topographic gradient implies westward, pressure-driven mantle flow beneath the basin, while the rapid spreading rate changes, on order 10 million years, require significant decoupling of regional plate motion from the large-scale mantle buoyancy distribution through a mechanically weak asthenosphere. Andean topographic growth in late Miocene can explain the most recent South Atlantic spreading velocity reduction, arising from increased plate boundary forcing associated with the newly elevated topography. But this mechanism is unlikely to explain the Late Cretaceous/Tertiary spreading variations, as changes in Andean paleoelevation at the time are small. We propose an unsteady pressure-driven flow component in the asthenosphere beneath the South Atlantic region to explain the Late Cretaceous/Tertiary spreading rate variations. Temporal changes in mantle flow due to temporal changes in regional mantle pressure gradients imply a correlation of horizontal and vertical motions: we find that this prediction from our models agrees with geologic and geophysical observations of the South Atlantic region, including episodes of passive margin uplift, regional basin reactivation, and magmatic activity
Making hidden spaces visible: using drawing as a method to illuminate new geographies
In recent years there has been a growing body of scholarship on the use of alternative research methods in Geography, and the social sciences more broadly, as well as ongoing interest in the connections between Geography and art. There has been much less attention, however, given to how drawing might be used practically or productively as a method, and to how it might allow geographers to reach or see places they couldn't otherwise. Although many researchers advocate conducting interviews and research in situ, thinking about the importance of location, there are times when entering a specific space is not possible. This paper details how the practice of drawing enabled me to make spaces that I wasn't able to visit as an ethnographic researcher, spaces that I felt were largely invisible to me, visible. While conducting fieldwork in a shelter for migrant domestic workers who had fled from their employers in Singapore, I used drawing as a way to shed a new light on the homes in which they had been working and to understand their everyday lives and experiences within them. This method made visible the living and working environments of women who had experienced employment abuse, as well as physical and sexual violence, while maintaining their anonymity and confidentiality, from a space of (relative) safety
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