10,817 research outputs found

    Comparison Of Sorghum And Indiangrass Chloroplast Genomes Using RFLPs

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    Sorghum (Sorghum bicolor (L.) Moench) and indiangrass (Sorghastrum nutans (L.) Nash) appear closely related based on morphological and chemotaxonomic characters. Each species could potentially provide desirable traits to the other. However, traditional breeding techniques have been unsuccessful in hybridizing these two species. The objective of this study was to determine the relatedness of sorghum and indiangrass chloroplast DNA using RFLPs. Eleven sorghum lines in several cytoplasms, two indiangrass popu1ations, and a corn line were studied using 60 proberestriction enzyme combinations. Principal component analysis of the results showed sorghum to be as closely related to corn as to indiangrass, with no overlap of clusters among the three groups

    Student E-Learning Intrinsic Motivation: A Qualitative Analysis

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    In the age of life-long learning and increased competition for time, motivation becomes a salient issue. Students need to be more intrinsically motivated in the absence of more formal structure. This is especially true in online learning environments where direct instructor influence is mitigated. Online learning environments typically embrace many choices in ways in which learning material is presented and interaction with students is supported in both individual and collaborative contexts. As such, it is imperative that we better understand the implications of various learning activities and associated technologies on aspects of intrinsic motivation in e-learning. In this paper we examine these effects through qualitative analysis of semi-structured interviews with students in an online MBA program. Results encourage use of a pedagogically driven portfolio of learning activities supported by well-selected and integrated audio, video, and data technologies. Extension to use of mobile devices in ubiquitous e-learning contexts is explored

    Experimentally realizable characterizations of continuous variable Gaussian states

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    Measures of entanglement, fidelity and purity are basic yardsticks in quantum information processing. We propose how to implement these measures using linear devices and homodyne detectors for continuous variable Gaussian states. In particular, the test of entanglement becomes simple with some prior knowledge which is relevant to current experiments.Comment: 4 pages, This paper supersedes quant-ph/020315

    THE ISOLATION AND IDENTIFICATION OF STEROIDAL SAPOGENINS IN SWITCHGRASS

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    Switchgrass (Panicum virgatum L.) has been reported to be hepatotoxic, causing photosensitization in lambs and horses. In this study we show the presence of steroidal saponins in two samples of switchgrass that has been implicated in the poisonings of sheep and horses. After hydrolysis of the saponins, diosgenin was determined to be the major sapogenin in both switchgrass samples. We also confirmed the presence of diosgenin in kleingrass after hydrolysis of saponins extracted from it

    Utilising semantic technologies for intelligent indexing and retrieval of digital images

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    The proliferation of digital media has led to a huge interest in classifying and indexing media objects for generic search and usage. In particular, we are witnessing colossal growth in digital image repositories that are difficult to navigate using free-text search mechanisms, which often return inaccurate matches as they in principle rely on statistical analysis of query keyword recurrence in the image annotation or surrounding text. In this paper we present a semantically-enabled image annotation and retrieval engine that is designed to satisfy the requirements of the commercial image collections market in terms of both accuracy and efficiency of the retrieval process. Our search engine relies on methodically structured ontologies for image annotation, thus allowing for more intelligent reasoning about the image content and subsequently obtaining a more accurate set of results and a richer set of alternatives matchmaking the original query. We also show how our well-analysed and designed domain ontology contributes to the implicit expansion of user queries as well as the exploitation of lexical databases for explicit semantic-based query expansion

    Transverse Pressure and Strangeness Dynamics in Relativistic Heavy Ion Reactions

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    Transverse hadron spectra from proton-proton, proton-nucleus and nucleus-nucleus collisions from 2 AGeV to 21.3 ATeV are investigated within two independent transport approaches (HSD and UrQMD). For central Au+Au (Pb+Pb) collisions at energies above Elab∌E_{\rm lab}\sim 5 AGeV, the measured K±K^{\pm} transverse mass spectra have a larger inverse slope parameter than expected from the default calculations. The additional pressure - as suggested by lattice QCD calculations at finite quark chemical potential ÎŒq\mu_q and temperature TT - might be generated by strong interactions in the early pre-hadronic/partonic phase of central Au+Au (Pb+Pb) collisions. This is supported by a non-monotonic energy dependence of v2/v_2/ in the present transport model.Comment: Proceedings of Strange Quark Matter 200

    Format zorgpad Voeding bij kanker

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    Het zorgpad ‘Voeding bij kanker’ beschrijft het (logistiek) pad dat de oncologische patiĂ«nt doorloopt binnen de voedingszorg vanaf het moment dat screening op behoefte aan voedingszorg plaatsvindt en verwijzing naar de diĂ«tist tot en met follow-up of palliatieve fase. Hierbij zijn het format en de indeling aangehouden van de IKNL-formats van (niet-)tumorspecifieke zorgpade

    Frequency dispersion reduction and bond conversion on n-type GaAs by in situ surface oxide removal and passivation

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    The method of surface preparation on n-type GaAs, even with the presence of an amorphous-Si interfacial passivation layer, is shown to be a critical step in the removal of accumulation capacitance frequency dispersion. In situ deposition and analysis techniques were used to study different surface preparations, including NH4OH, Si-flux, and atomic hydrogen exposures, as well as Si passivation depositions prior to in situ atomic layer deposition of Al2O3. As–O bonding was removed and a bond conversion process with Si deposition is observed. The accumulation capacitance frequency dispersion was removed only when a Si interlayer and a specific surface clean were combined

    Identification of non-dot/icm suppressors of the Legionella pneumophila △dotL lethality phenotype

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    Legionella pneumophila, a causative agent of bacterial pneumonia, survives inside phagocytic cells by avoiding rapid targeting to the lysosome. This bacterium utilizes a type IVB secretion system, encoded by the dot/icm genes, to replicate inside host cells. DotL, a critical component of the Dot/Icm secretion apparatus, functions as the type IV coupling protein. In contrast to most dot/icm genes, which are dispensable for growth on bacteriological media, dotL is required for the viability of wild-type L. pneumophila. Previously we reported that ΔdotL lethality could be suppressed by inactivation of the Dot/Icm complex via mutations in other dot/icm genes. Here we report the isolation of non-dot/icm suppressors of this phenotype. These ΔdotL suppressors include insertions that disrupt the function of the L. pneumophila homologs of cpxR, djlA, lysS, and two novel open reading frames, lpg0742 and lpg1594, that we have named ldsA and ldsB for lethality of ΔdotL suppressor. In addition to suppressing ΔdotL lethality, inactivation of these genes in a wild-type strain background causes a range of defects in L. pneumophila virulence traits, including intracellular growth, implicating these factors in the proper function of the Dot/Icm complex. Consistent with previous data showing a role for the cpx system in regulating expression of several dot/icm genes, the cpxR insertion mutant produced decreased levels of three Dot/Icm proteins, DotA, IcmV, and IcmW. The remaining four suppressors did not affect the steady-state levels of any Dot/Icm protein and are likely to represent the first identified factors necessary for assembly and/or activation of the Dot/Icm secretion complex
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