Home About us Contact
|
Home About us Contact | ||
|
|
||
Linear Sequence (linear + sequence)
Selected AbstractsTHE "INS" AND "OUTS" OF HISTORY: REVISION AS NON-PLACEHISTORY AND THEORY, Issue 4 2007MARNIE HUGHES-WARRINGTON ABSTRACT Revision in history is conventionally characterized as a linear sequence of changes over time. Drawing together the contributions of those engaged in historiographical debates that are often associated with the term "revision," however, we find our attention directed to the spaces rather than the sequences of history. Contributions to historical debates are characterized by the marked use of spatial imagery and spatialized language. These used to suggest both the demarcation of the "space of history" and the erasure of existing historiographies from that space. Bearing these features in mind, the essay argues that traditional, temporally oriented explanations for revision in history, such as Thomas S. Kuhn's Structure of Scientific Revolutions, miss the mark, and that a more promising line of explanation arises from the combined use of Michel Foucault's idea of "heterotopias" and Marc Augé's idea of "non-places." Revision in history is to be found where writers use imagery to move readers away from rival historiographies and to control their movement in the space of history toward their desired vision. Revision is thus associated more with control than with liberation. [source] Eight-Step Synthesis of RoutiennocinADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2008Kenji Matsumoto Abstract Routiennocin is a member of a family of polycyclic pyrrole ether antibiotics that simultaneously uncouple oxidative phosphorylation and inhibit ATPase as a result of selective complexation of divalent metal ions. We describe a concise synthesis of routiennocin with the longest linear sequence of 8 steps. Our synthesis features a unique bi-directional strategy, which entails a sequential ring-opening/cross metathesis of a highly strained cyclopropenone acetal. This approach enables rapid and highly convergent assembly of the fully extended polyketide subunit of this natural product from readily available homoallylic alcohol precursors. [source] Analogies between linguistics and information theoryJOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 3 2007Julian Warner An analogy is established between the syntagm and paradigm from Saussurean linguistics and the message and messages for selection from the information theory initiated by Claude Shannon. The analogy is pursued both as an end in itself and for its analytic value in understanding patterns of retrieval from full-text systems. The multivalency of individual words when isolated from their syntagm is contrasted with the relative stability of meaning of multiword sequences, when searching ordinary written discourse. The syntagm is understood as the linear sequence of oral and written language. Saussure's understanding of the word, as a unit that compels recognition by the mind, is endorsed, although not regarded as final. The lesser multivalency of multiword sequences is understood as the greater determination of signification by the extended syntagm. The paradigm is primarily understood as the network of associations a word acquires when considered apart from the syntagm. The restriction of information theory to expression or signals, and its focus on the combinatorial aspects of the message, is sustained. The message in the model of communication in information theory can include sequences of written language. Shannon's understanding of the written word, as a cohesive group of letters, with strong internal statistical influences, is added to the Saussurean conception. Sequences of more than one word are regarded as weakly correlated concatenations of cohesive units. [source] Nonlinear functionals of the periodogramJOURNAL OF TIME SERIES ANALYSIS, Issue 5 2002GILLES FAY A central limit theorem is stated for a wide class of triangular arrays of nonlinear functionals of the periodogram of a stationary linear sequence. Those functionals may be singular and not-bounded. The proof of this result is based on Bartlett decomposition and an existing counterpart result for the periodogram of an independent and identically distributed sequence, here taken to be the driving noise. The main contribution of this paper is to prove the asymptotic negligibility of the remainder term from Bartlett decomposition, feasible under short dependence assumption. As it is highlighted by applications (to estimation of nonlinear functionals of the spectral density, robust spectral estimation, local polynomial approximation and log-periodogram regression), this extends may results until then tied to Gaussian assumption. [source] The Linear Angiosperm Phylogeny Group (LAPG) III: a linear sequence of the families in APG IIIBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2009ELSPETH HASTON The publication of the third Angiosperm Phylogeny Group (APG) classification (APG III. 2009. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III. Botanical Journal of the Linnean Society161: 128,131) has resulted in the need for a revised systematic listing of the accepted families. This linear APG III (LAPG III) sequence of families is presented here. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161, 128,131. [source] Concise Total Synthesis of the Thiazolyl Peptide Antibiotic GE2270,ACHEMISTRY - A EUROPEAN JOURNAL, Issue 8 2008Oscar Delgado Dr. Abstract The potent antibiotic thiazolylpeptide GE2270,A was synthesized starting from N - tert -butyloxycarbonyl protected valine in a longest linear sequence of 20 steps and with an overall yield of 4.8,%. Key strategy was the assembly of the 2,3,6-trisubstituted pyridine core by consecutive cross-coupling reactions starting from 2,6-dibromo-3-iodopyridine. The complete Southern fragment was installed by Negishi cross-coupling of 3-zincated 2,6-dibromopyridine at the terminal 2-iodothiazole of a trithiazole (87,%). The substituent at C-6 representing the Northern part of the molecule was introduced in form of the truncated tert -butyl 2-bromothiazole-4-carboxylate after metalation to a zinc reagent by another Negishi cross-coupling (48,%). Decisive step of the whole sequence was the macrocyclization to a 29-membered macrolactam, which was conducted as an intramolecular Stille cross-coupling occurring at C-2 of the pyridine core and providing the desired product in 75,% yield. The required stannane was obtained by amide bond formation (87,%) between a complex dithiazole fragment representing the Eastern part of GE2270,A and a 3,6-disubstituted 2-bromopyridine. Final steps included attachment of a serine-proline amide dipeptide to the Northern part of the molecule (65,%), formation of the oxazoline ring and silyl ether deprotection (55,% overall). [source] The influence of sward canopy structure on foraging decisions by grazing cattle.GRASS & FORAGE SCIENCE, Issue 2 2003Abstract Patch selection by grazing dairy cows in response to simultaneous variation in combinations of sward structural characteristics was examined in three experiments in which four mature dairy cows were offered a choice of patches (typically 0.9 m × 0.9 m) of perennial ryegrass (Lolium perenne) presented in a linear arrangement. Treatments involved combinations of variations in sward height, stubble height and/or depth of regrowth, prepared by preliminary cutting treatments. They were arranged in balanced sets of four to nine treatments, which were arranged in linear sequences of eighteen to twenty-seven patches. Within experiments, sequences were balanced across replicate sets of patches, which were grazed separately by individual cows. The number of bites removed and the residence time for each patch were highly correlated in all three experiments, and the results are reported using number of bites per patch as an estimator of foraging behaviour. In the first experiment, with vegetative swards, cows preferentially selected the tallest swards. When swards comprising reproductive stem were offered in Experiment 2, cows selectively grazed short-stubble swards rather than tall-stubble swards, although both offered a similar depth of regrowth. Cows did not exhibit preference for swards comprising the greatest quantity of leaf mass, indicating that the spatial distribution of plant components assumed greater importance. In the third experiment, the number of bites removed increased with increasing depth of regrowth, and was negatively correlated with sward height. The three patch-appraisal cues investigated were broadly ranked in order of importance as (i) depth of regrowth, (ii) sward maturity and (iii) sward height. There was no evidence, at least at a short temporal scale, that patch behaviour was influenced by conditions in adjacent patches, suggesting that the cows assessed grazing opportunities on a patch-by-patch basis. [source] | ||||||||||