Resonant tunneling controlled by laser and constant electric fields

We develop the concept of scattering matrix and we use it to perform stable numerical calculations of resonant tunneling of electrons through a multiple potential barrier in a semiconductor heterostructure. Electrons move in two external nonperturbative electric fields: constant and oscillating in time. We apply our algorithm for different strengths and spatial configurations of the fields.Comment: 10 pages, 11 figure

Response of deep-water agglutinated foraminifera to dysoxic conditions in the California Borderland basins

Analysis of agglutinated benthic foraminifera from surface samples collected in the San Pedro and Santa Catalina Basins reveals a predictable relationship between the proportions of morphogroups with decreasing bottom water oxygen levels and with the TOC content of the surficial sediment. Living (Rose Bengal stained) foraminiferal faunas from dysaerobic environments display low diversity and high dominance, suggesting stressed conditions. There is an inverse relationship between oxygen and the relative abundance of deep infaunal morphogroups. Samples collected from shallow stations above the oxygen minimum zone are comprised of epifaunal and shallow infaunal morphotypes. At intermediate depths (~500 m), there is a peak in the abundance of suspension-feeding and "climbing" forms (watchglass-shaped trochamminids attached to Rhabdammina). Specimens from intermediate stations display the largest overall size. Deeper in the San Pedro Basin the living fauna is dominated by a small, flattened, tapered, species that is interpreted as having a deep infaunal microhabitat. In the dysaerobic environments off California the greatest degree of faunal change occurs when bottom water dissolved oxygen values drop from 0.5 ml/l to 0.2 ml/l. The effect of TOC content on the benthic fauna is demonstrated at two stations from the same depth in the San Pedro Basin. The station with the higher TOC content (4.2% vs. 2.9%) contains greater proportions of the small, deep infaunal morphotype. These faunal changes may be attributed to differences in the depth of the oxygenated zone within the sediment surface layer. Agglutinated faunas from areas that experience seasonal anoxia are comprised of a large proportion of opportunistic forms such as Reophax and Psammosphaera. These are the same taxa that colonised abiotic sediment trays in a recolonisation experiment in the Panama Basin. This study further demonstrates that agglutinated foraminiferal morphotypes respond in a similar manner to calcareous benthic foraminifera in dysaerobic environments

Study of 'ratio' automatically assembled structures final report, 15 jun. 1963 - 15 jun. 1964

Structural analysis of RATIO automatically assembled panel sections for application to spaceborne paraboloidal antenn

Plectoeratidus subarcticus, n.gen., n.sp., a new agglutinated foraminifer from the Upper Cretaceous of the western Barents Sea

We describe the new foraminiferal genus and species Plectoeratidus subarcticus n.gen. n.sp., from the Upper Cretaceous deep-water deposits of the Kviting and Kveite formations in the western Barents Sea. The genus is characterised by its planispiral-biserial-uniserial chamber arrangement, terminal aperture and lateral compression. The biometric analysis of test ontogenesis has been applied to document its dimorphism attributed to megalospheric and microspheric generations. This taxon may represent an evolutionary transition between the Cretaceous genera Spiroplectammina or Bolivinopsis and the Cenozoic genus Eratidus. The taxon appears to be endemic to the flysch-type agglutinated foraminiferal assemblages in the Norwegian Sea area

Tracking the Impact of Your Web-Based Content

Google™ Analytics is an easy-to-use Web analytics program that gives you insight into Web site traffic. Many Extension programs use the Web to distribute information. Extension program impact has traditionally been assessed through surveys or by the number of publications sold or requested, whereas tracking Web impact has been more difficult. Although site visits and page views could be tracked with previous Web analytics technology, Google™ Analytics allows for tracking of additional useful information. This article highlights a few useful features of Google™ Analytics and demonstrates how to track the impact of Web-based content

Tracking the Impact of Your Web-Based Content

Google™ Analytics is an easy-to-use Web analytics program that gives you insight into Web site traffic. Many Extension programs use the Web to distribute information. Extension program impact has traditionally been assessed through surveys or by the number of publications sold or requested, whereas tracking Web impact has been more difficult. Although site visits and page views could be tracked with previous Web analytics technology, Google™ Analytics allows for tracking of additional useful information. This article highlights a few useful features of Google™ Analytics and demonstrates how to track the impact of Web-based content

The tractability frontier of well-designed SPARQL queries

We study the complexity of query evaluation of SPARQL queries. We focus on the fundamental fragment of well-designed SPARQL restricted to the AND, OPTIONAL and UNION operators. Our main result is a structural characterisation of the classes of well-designed queries that can be evaluated in polynomial time. In particular, we introduce a new notion of width called domination width, which relies on the well-known notion of treewidth. We show that, under some complexity theoretic assumptions, the classes of well-designed queries that can be evaluated in polynomial time are precisely those of bounded domination width

On knottings in the physical Hilbert space of LQG as given by the EPRL model

We consider the EPRL spin foam amplitude for arbitrary embedded two-complexes. Choosing a definition of the face- and edge amplitudes which lead to spin foam amplitudes invariant under trivial subdivisions, we investigate invariance properties of the amplitude under consistent deformations, which are deformations of the embedded two-complex where faces are allowed to pass through each other in a controlled way. Using this surprising invariance, we are able to show that in the physical Hilbert space as defined by the sum over all spin foams contains no knotting classes of graphs anymore.Comment: 22 pages, 14 figure