166 research outputs found
Some Applications of the Bounded Convergence Theorem for an Introductory Course in Analysis
The Arzela bounded convergence theorem is the special case of the Lebesgue dominated convergence theorem in which the functions are assumed to be Riemann integrable
XTE J2123-058: A New Neutron Star X-Ray Transient
We report on optical and RXTE observations of a new high-latitude bursting
X-ray transient, XTE J2123-058. We identified the optical counterpart, measured
the 5.9573 hr orbital period and constrained the binary inclination and the
source distance. The distance lower limit indicates that the source is at least
2.6 kpc from the Galactic plane, which is unusual for an LMXB. RXTE
observations were made between June and August 1998 during the first detected
outburst from this source. We describe correlations between X-ray timing and
spectral properties and discuss the possibility that the propeller mechanism
turned on during the decay of the outburst. During one of the RXTE
observations, we detect a pair of high frequency QPOs at 847.1 +/- 5.5 Hz and
1102 +/- 13 Hz simultaneously. According to the beat frequency model, the QPO
separation implies a neutron star spin period near 3.9 ms. As the X-ray flux
decreases at the end of the outburst, the amplitude of the optical modulation
increases significantly. This behavior can be explained if the size of the
accretion disk decreases during the decay of the outburst.Comment: 24 pages, 9 figures, accepted by Ap
Thirty-two Goldbach Variations
We give thirty-two diverse proofs of a small mathematical gem--the
fundamental Euler sum identity zeta(2,1)=zeta(3) =8zeta(\bar 2,1). We also
discuss various generalizations for multiple harmonic (Euler) sums and some of
their many connections, thereby illustrating both the wide variety of
techniques fruitfully used to study such sums and the attraction of their
study.Comment: v1: 34 pages AMSLaTeX. v2: 41 pages AMSLaTeX. New introductory
material added and material on inequalities, Hilbert matrix and Witten zeta
functions. Errors in the second section on Complex Line Integrals are
corrected. To appear in International Journal of Number Theory. Title change
Elliptic integral evaluations of Bessel moments
We record what is known about the closed forms for various Bessel function
moments arising in quantum field theory, condensed matter theory and other
parts of mathematical physics. More generally, we develop formulae for
integrals of products of six or fewer Bessel functions. In consequence, we are
able to discover and prove closed forms for with integers and , obtaining new results
for the even moments and . We also derive new closed forms
for the odd moments with and for with , relating the latter to Green functions on
hexagonal, diamond and cubic lattices. We conjecture the values of
, make substantial progress on the evaluation of ,
and and report more limited progress regarding
, and . In the process, we obtain 8
conjectural evaluations, each of which has been checked to 1200 decimal places.
One of these lies deep in 4- dimensional quantum field theory and two are
probably provable by delicate combinatorics. There remains a hard core of five
conjectures whose proofs would be most instructive, to mathematicians and
physicists alike.Comment: 51 pages, 1 Postscript figure, uses amsmath.sty, added reference
Earth BioGenome Project: Sequencing life for the future of life.
Increasing our understanding of Earth's biodiversity and responsibly stewarding its resources are among the most crucial scientific and social challenges of the new millennium. These challenges require fundamental new knowledge of the organization, evolution, functions, and interactions among millions of the planet's organisms. Herein, we present a perspective on the Earth BioGenome Project (EBP), a moonshot for biology that aims to sequence, catalog, and characterize the genomes of all of Earth's eukaryotic biodiversity over a period of 10 years. The outcomes of the EBP will inform a broad range of major issues facing humanity, such as the impact of climate change on biodiversity, the conservation of endangered species and ecosystems, and the preservation and enhancement of ecosystem services. We describe hurdles that the project faces, including data-sharing policies that ensure a permanent, freely available resource for future scientific discovery while respecting access and benefit sharing guidelines of the Nagoya Protocol. We also describe scientific and organizational challenges in executing such an ambitious project, and the structure proposed to achieve the project's goals. The far-reaching potential benefits of creating an open digital repository of genomic information for life on Earth can be realized only by a coordinated international effort
Why sequence all eukaryotes?
Life on Earth has evolved from initial simplicity to the astounding complexity we experience today. Bacteria and archaea have largely excelled in metabolic diversification, but eukaryotes additionally display abundant morphological innovation. How have these innovations come about and what constraints are there on the origins of novelty and the continuing maintenance of biodiversity on Earth? The history of life and the code for the working parts of cells and systems are written in the genome. The Earth BioGenome Project has proposed that the genomes of all extant, named eukaryotes-about 2 million species-should be sequenced to high quality to produce a digital library of life on Earth, beginning with strategic phylogenetic, ecological, and high-impact priorities. Here we discuss why we should sequence all eukaryotic species, not just a representative few scattered across the many branches of the tree of life. We suggest that many questions of evolutionary and ecological significance will only be addressable when whole-genome data representing divergences at all of the branchings in the tree of life or all species in natural ecosystems are available. We envisage that a genomic tree of life will foster understanding of the ongoing processes of speciation, adaptation, and organismal dependencies within entire ecosystems. These explorations will resolve long-standing problems in phylogenetics, evolution, ecology, conservation, agriculture, bioindustry, and medicine
Standards recommendations for the Earth BioGenome Project
A global international initiative, such as the Earth BioGenome Project (EBP), requires both agreement and coordination on standards to ensure that the collective effort generates rapid progress toward its goals. To this end, the EBP initiated five technical standards committees comprising volunteer members from the global genomics scientific community: Sample Collection and Processing, Sequencing and Assembly, Annotation, Analysis, and IT and Informatics. The current versions of the resulting standards documents are available on the EBP website, with the recognition that opportunities, technologies, and challenges may improve or change in the future, requiring flexibility for the EBP to meet its goals. Here, we describe some highlights from the proposed standards, and areas where additional challenges will need to be met
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