4,210 research outputs found
A remarkable sequence related to and
We prove that five ways to define entry A086377 in the On-Line Encyclopedia
of Integer Sequences do lead to the same integer sequence
Abstract numeration systems on bounded languages and multiplication by a constant
A set of integers is -recognizable in an abstract numeration system if
the language made up of the representations of its elements is accepted by a
finite automaton. For abstract numeration systems built over bounded languages
with at least three letters, we show that multiplication by an integer
does not preserve -recognizability, meaning that there always
exists a -recognizable set such that is not
-recognizable. The main tool is a bijection between the representation of an
integer over a bounded language and its decomposition as a sum of binomial
coefficients with certain properties, the so-called combinatorial numeration
system
A versatile maskless microscope projection photolithography system and its application in light-directed fabrication of DNA microarrays
We present a maskless microscope projection lithography system (MPLS), in
which photomasks have been replaced by a Digital Micromirror Device type
spatial light modulator (DMD, Texas Instruments). Employing video projector
technology high resolution patterns, designed as bitmap images on the computer,
are displayed using a micromirror array consisting of about 786000 tiny
individually addressable tilting mirrors. The DMD, which is located in the
image plane of an infinity corrected microscope, is projected onto a substrate
placed in the focal plane of the microscope objective. With a 5x(0.25 NA) Fluar
microscope objective, a fivefold reduction of the image to a total size of 9
mm2 and a minimum feature size of 3.5 microns is achieved. Our system can be
used in the visible range as well as in the near UV (with a light intensity of
up to 76 mW/cm2 around the 365 nm Hg-line). We developed an inexpensive and
simple method to enable exact focusing and controlling of the image quality of
the projected patterns. Our MPLS has originally been designed for the
light-directed in situ synthesis of DNA microarrays. One requirement is a high
UV intensity to keep the fabrication process reasonably short. Another demand
is a sufficient contrast ratio over small distances (of about 5 microns). This
is necessary to achieve a high density of features (i.e. separated sites on the
substrate at which different DNA sequences are synthesized in parallel fashion)
while at the same time the number of stray light induced DNA sequence errors is
kept reasonably small. We demonstrate the performance of the apparatus in
light-directed DNA chip synthesis and discuss its advantages and limitations.Comment: 12 pages, 9 figures, journal articl
The Gargasian (Middle Aptian) of La Marcouline section at Cassis-La Bédoule (SE France): Stable isotope record and orbital cyclicity
International audienceBulk rock stable isotope analysis of La Marcouline section (Cassis-La Bédoule area, SE France) revealed a general trend of decreasing δ13C and δ18O values from the bottom to the top of the section. The decrease in δ13C values reflects a global trend in Middle Aptian times, namely a return to pre-excursion values of δ13C values following a major, positive excursion in the Early Aptian, which is a reflection of the Oceanic Anoxic Event (OAE) 1a. Power spectra of the bedding rhythms suggest that precessional and long eccentricity cycles of the Milankovitch band controlled the deposition of marl-limestone bundles. This can be interpreted as the result of a forcing by insolation at low latitudes which resulted in a monsoon-controlled precipitation pattern, that in turn induced the deposition of clay-rich beds. Conversely, limestone beds were formed in periods of dryer climate. Higher sea-surface productivity during wet periods may have been caused by an increase in continental runoff and a consequent enhancement in the delivery of nutrients to epicontinental basins. An orbital cyclicity in the sedimentary patterns in La Marcouline section provides the opportunity to calibrate the duration of the well-established G. ferreolensis foraminiferal Zone with that of orbital chronology. The G. ferreolensis Zone at Cassis-La Bédoule spans 33 precessional cycles and its duration is thus estimated to be approximately 760 ka. This length of time is significantly shorter than the estimates of published timescales for this zone and thus may be an argument for proposing that the Gargasian substage is significantly shorter than its currently accepted range
A precise bare simulation approach to the minimization of some distances. Foundations
In information theory -- as well as in the adjacent fields of statistics,
machine learning, artificial intelligence, signal processing and pattern
recognition -- many flexibilizations of the omnipresent Kullback-Leibler
information distance (relative entropy) and of the closely related Shannon
entropy have become frequently used tools. To tackle corresponding constrained
minimization (respectively maximization) problems by a newly developed
dimension-free bare (pure) simulation method, is the main goal of this paper.
Almost no assumptions (like convexity) on the set of constraints are needed,
within our discrete setup of arbitrary dimension, and our method is precise
(i.e., converges in the limit). As a side effect, we also derive an innovative
way of constructing new useful distances/divergences. To illustrate the core of
our approach, we present numerous examples. The potential for widespread
applicability is indicated, too; in particular, we deliver many recent
references for uses of the involved distances/divergences and entropies in
various different research fields (which may also serve as an interdisciplinary
interface)
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