Hasil untuk "Maps"

Menampilkan 20 dari ~2346076 hasil · dari CrossRef, DOAJ, Semantic Scholar

JSON API
S2 Open Access 2002
A Knowledge Compilation Map

Adnan Darwiche, P. Marquis

We propose a perspective on knowledge compilation which calls for analyzing different compilation approaches according to two key dimensions: the succinctness of the target compilation language, and the class of queries and transformations that the language supports in polytime. We then provide a knowledge compilation map, which analyzes a large number of existing target compilation languages according to their succinctness and their polytime transformations and queries. We argue that such analysis is necessary for placing new compilation approaches within the context of existing ones. We also go beyond classical, flat target compilation languages based on CNF and DNF, and consider a richer, nested class based on directed acyclic graphs (such as OBDDs), which we show to include a relatively large number of target compilation languages.

1025 sitasi en Computer Science, Mathematics
S2 Open Access 1994
Assignment of 30 microsatellite loci to the linkage map of Arabidopsis.

C. Bell, J. R. Ecker

Thirty microsatellite loci were assigned to the Arabidopsis linkage map. Several microsatellite sequences in Arabidopsis DNA were found by searching the EMBL and GenBank databases, and a number of these were subsequently found to detect polymorphisms between different Arabidopsis strains by the polymerase chain reaction (PCR). After the presence of microsatellites in Arabidopsis and their utility for genetic mapping had been demonstrated, systematic screening for (CA)n and (GA)n sequences was carried out on marker-selected plasmid libraries and a small-insert genomic library. Positive clones were sequenced, PCR primers flanking the repeats were synthesized, and PCR was carried out on different strains to look for useful polymorphisms. Surprisingly, of 18 (CA)n repeats (n > 13), only one was polymorphic. In contrast, 25 of 30 (GA)n repeats, 2 of 3 (AT)n repeats, and 2 of 4 (A)n repeats were polymorphic. The majority of the (CA)n repeats were complex, with adjacent short di-, tri-, or tetranucleotide repeats, whereas most of the (GA)n, (TA)n, and (A)n repeats were simple. The (CA)n repeats were also refractory to PCR analysis, requiring extensive optimization of PCR conditions, whereas the other repeat classes were mostly amplified with a single set of standard conditions. When polymorphisms were detected, the microsatellites were mapped using a set of recombinant inbred lines originating from a cross between the strains Columbia and Landsberg erecta.

1113 sitasi en Biology, Medicine
S2 Open Access 2004
A Quantitative Map of the Circuit of Cat Primary Visual Cortex

T. Binzegger, R. Douglas, K. Martin

We developed a quantitative description of the circuits formed in cat area 17 by estimating the “weight” of the projections between different neuronal types. To achieve this, we made three-dimensional reconstructions of 39 single neurons and thalamic afferents labeled with horseradish peroxidase during intracellular recordings in vivo. These neurons served as representatives of the different types and provided the morphometrical data about the laminar distribution of the dendritic trees and synaptic boutons and the number of synapses formed by a given type of neuron. Extensive searches of the literature provided the estimates of numbers of the different neuronal types and their distribution across the cortical layers. Applying the simplification that synapses between different cell types are made in proportion to the boutons and dendrites that those cell types contribute to the neuropil in a given layer, we were able to estimate the probable source and number of synapses made between neurons in the six layers. The predicted synaptic maps were quantitatively close to the estimates derived from the experimental electron microscopic studies for the case of the main sources of excitatory and inhibitory input to the spiny stellate cells, which form a major target of layer 4 afferents. The map of the whole cortical circuit shows that there are very few “strong” but many “weak” excitatory projections, each of which may involve only a few percentage of the total complement of excitatory synapses of a single neuron.

898 sitasi en Biology, Medicine

Halaman 42 dari 117304