20,015 research outputs found
Author Co-Citation Analysis (ACA): a powerful tool for representing implicit knowledge of scholar knowledge workers
Full text linkIn the last decade, knowledge has emerged as one of the most important and valuable organizational assets. Gradually this importance caused to emergence of new discipline entitled ―knowledge management‖. However one of the major challenges of knowledge management is conversion implicit or tacit knowledge to explicit knowledge. Thus Making knowledge visible so that it can be better accessed, discussed, valued or generally managed is a long-standing objective in knowledge management. Accordingly in this paper author co- citation analysis (ACA) will be proposed as an efficient technique of knowledge visualization in academia (Scholar knowledge workers)
A case-cohort study for the disease natural history of adenoma-carcinoma and de novo carcinoma and surveillance of colon and rectum after polypectomy: implication for efficacy of colonoscopy
No full textAccumulation of butyltin compounds in the pantropical spotted dolphin, Stenella attenuate, from the coasts of Taiwan.
No full textRecommended from our members
Tandem quadruplication of HMA4 in the zinc (Zn) and cadmium (Cd) hyperaccumulator noccaea caerulescens
Full text linkZinc (Zn) and cadmium (Cd) hyperaccumulation may have evolved twice in the Brassicaceae, in Arabidopsis halleri and in the Noccaea genus. Tandem gene duplication and deregulated expression of the Zn transporter, HMA4, has previously been linked to Zn/Cd hyperaccumulation in A. halleri. Here, we tested the hypothesis that tandem duplication and deregulation of HMA4 expression also occurs in Noccaea. A Noccaea caerulescens genomic library was generated, containing 36,864 fosmid pCC1FOSTM clones with insert sizes ~20–40 kbp, and screened with a PCR-generated HMA4 genomic probe. Gene copy number within the genome was estimated through DNA fingerprinting and pooled fosmid pyrosequencing. Gene copy numbers within individual clones was determined by PCR analyses with novel locus specific primers. Entire fosmids were then sequenced individually and reads equivalent to 20-fold coverage were assembled to generate complete whole contigs. Four tandem HMA4 repeats were identified in a contiguous sequence of 101,480 bp based on sequence overlap identities. These were flanked by regions syntenous with up and downstream regions of AtHMA4 in Arabidopsis thaliana. Promoter-reporter b-glucuronidase (GUS) fusion analysis of a NcHMA4 in A. thaliana revealed deregulated expression in roots and shoots, analogous to AhHMA4 promoters, but distinct from AtHMA4 expression which localised to the root vascular tissue. This remarkable consistency in tandem duplication and deregulated expression of metal transport genes between N. caerulescens and A. halleri, which last shared a common ancestor >40 mya, provides intriguing evidence that parallel evolutionary pathways may underlie Zn/Cd hyperaccumulation in Brassicaceae
GEANT4 Simulations and Experimental Tests of a Silicon CD Detector
Full text link In nuclear astrophysics, there are still undiscovered areas involving unstable nuclei, like the nucleosynthesis in exploding stars. The unstable nuclei are extremely difficult to produce in the laboratory for study since they decay away quickly once they are formed. To make the unstable nuclei available in the laboratory, Canada has built one of the best facilities in the world for nuclear astrophysics studies with radioactive beams, called TRIUMF-ISAC. Its recent upgrade to ISAC-2 can produce even heavier radioactive beams with higher energy. To fully utilize the ISAC-2 facility, a high-segmented HPGe γ-ray detector-TIGRESS, has been
developed to study exotic nuclei using the well-established technique of Coulomb Excitation. As an essential part of the TIGRESS facility, auxiliary detectors, such as silicon
detectors, are used to improve the sensitivity of the experiments through Doppler correction. Two types of silicon detectors will be used. One is the CD-shaped double-sided silicon strip detector, which is the topic of this thesis. The other one is the silicon barrel detector. This thesis will discuss the computer simulations and experimental tests of the CD detector. Simulations were made using a simulation toolkit GEANT4, which was run under the Linux system. The goal was to test the hypothesis that measurements of the energies of heavy ions in Coulomb excitation may improve the Doppler correction by constraining the scattering location in a thick target. To test the performance of the simulated CD detector, simple simulations were performed for shooting calibration alpha particles from an 241Am source first directly onto the CD and second through a thin target onto the CD. The goal of additional simulations was to attempt to determine the corresponding scattering depth in a thick target by putting an energy cut on the spectrum of the scattered beam detected in the
CD. These simulation results verify the possibility of such localization, though the resolution is not very good. Experimental tests for the CD detector are aimed to obtain the energy resolution for each strip element of the CD and to have at least 8 channels instrumented in our test lab before this detector is sent to TIGRESS facility. The test station
including electronics and detector systems and all results from initial tests are described in detail in this thesis.ThesisMaster of Science (MSc
Cd-regulated gene expression in Datura innoxia
Full text linkThe effects of Cd on the expression of specific proteins and transcripts have been examined in Cd-resistant (Cd300) and Cd-sensitive cultures of Datura innoxia. 2D PAGE analysis of the soluble fraction of D. innoxia protein proved problematic. Proteins precipitated on the surface of lEF gels. This was overcome by loading the samples in the gel mixture prior to polymerisation. Polymerisation of gels containing protein extracted from Cd-exposed cells only occurred when PCs, Cd and other components were resolved from the proteins eluting in the void volume following fractionation by gel filtration chromatography (Sephadex G50). Two peptides, designated Cd-1 and Cd-2, were detected in the Cd300 cells only after exposure to Cd. Cd-1 and Cd-2 were also both detected following exposure of the Cd300 cells to 125 piM Cu or Zn, or HS (42 ˚C 4 h). Neither Cd-1 nor Cd-2 were observed in protein extracts from WDI cells exposed to 125 μM Cd for 8 h. Both Cd-1 and Cd-2 proved refractory to Edman degradation while the N-terminal 30 amino acids of a third, constitutively expressed protein, designated Protein-3, were determined using equivalent procedures. This protein showed sequence similarity to PR proteins. Although cleavage of Cd-1 and Cd-2 generated polypeptides which were not terminally blocked, no sequence information was obtained from these polypeptides, even following purification using standard techniques. Oligonucleotide primers designed from the amino acid sequence of Protein-3 were successfully used to amplify, from cDNA, a fragment which was cloned, sequenced and shown to encode the characterised protein. A longer fragment was also amplified from cDNA by RACE PGR. However, this product was not cloned. In order to identify cDNA sequences encoding Cd-1 and Cd-2 an expression cDNA library was prepared and antibodies raised against the two peptides. However, no antigenicity could be detected when antisera raised against Cd-1 or Cd-2, or the purified IgG fractions, were used to probe western blots. The XZAP cDNA (Cd-exposed) library was "differentially screened" in order to isolate clones corresponding to Cd-induced genes. This led to the isolation of two Cd- induced clones designated Cd-6 (949 bp) and Cd-8 (659 bp). Both clones hybridised to transcripts of approximately 900 bp. Transcripts were also detected in RNA samples extracted from D. innoxia exposed to HS (42 ˚C 4 h), however no transcripts were detected in WDI cells exposed to Cd. Southern blots revealed hybridisation to multiple bands, possibly indicating the presence of a gene family. A motif, C-C-X-C-C, found in the a-domain of metallothioneins, was identified in Cd-6. This may represent a putative metal binding site in Cd-6
Progression of pre-hypertension, stage 1 and 2 hypertension (JNC 7): a population-based study in Keelung, Taiwan (Keelung Community-based Integrated Screening No 9)
No full textCD-ROM és/vagy online
No full textCHING-CHIH CHEN: CD-ROM survey in America academic and college libraries. = 11 th IOLIM, p. 9-12.DAY, J. M.: LISA on CD-ROM - a user evaluation. = 11 th IOLIM, p. 273-284.HATVÁNY, B.: Comparision of CD-ROM and online. = 11th IOLIM, p. 285-290
Chemical speciation of environmentally significant metals with inorganic ligands. Part 4: The Cd2+ + OH–, Cl–, CO32–, SO42–, and PO43– systems (IUPAC Technical Report)
Full text linkThe numerical modeling of Cd-II speciation amongst the environmental inorganic ligands Cl-, OH-, CO32-, SO42-, and PO43- requires reliable values for the relevant stability (formation) constants. This paper compiles and provides a critical review of these constants and related thermodynamic data. It recommends values of log(10) beta(p,q,r) valid at I-m = 0 mol kg(-1) and 25 degrees C (298.15 K), along with the equations and empirical reaction ion interaction coefficients, Delta epsilon, required to calculate log(10)beta(p),(,q,r) values at higher ionic strengths using the Bronsted-Guggenheim-Scatchard specific ion interaction theory (SIT). Values for the corresponding reaction enthalpies, Delta H-r, are reported where available. Unfortunately, with the exception of the Cd-II-chlorido system and (at low ionic strengths) the Cd-II-sulfato system, the equilibrium reactions for the title systems are relatively poorly characterized.
In weakly acidic fresh water systems (-log(10){[H+]/c degrees} < 6), in the absence of organic ligands (e. g., humic substances), Cd-II speciation is dominated by Cd2+(aq), with CdSO4(aq) as a minor species. In this respect, Cd-II is similar to Cu-II [2007PBa] and Pb-II [2009PBa]. However, in weakly alkaline fresh water solutions, 7.5 < -log(10) {[H+]/c degrees} < 8.6, the speciation of Cd-II is still dominated by Cd2+(aq), whereas for Cu-II [2007PBa] and Pb-II [2009PBa] the carbonato-species MCO3(aq) dominates. In weakly acidic saline systems (-log(10) {[H+]/c degrees} < 6; -log(10) {[Cl-]/c degrees} < 2.0) the speciation is dominated by CdCln(2-n)+ complexes, (n = 1-3), with Cd2+(aq) as a minor species. This is qualitatively similar to the situation for Cu-II and Pb-II. However, in weakly alkaline saline solutions, including seawater, the chlorido-complexes still dominate the speciation of Cd-II because of the relatively low stability of CdCO3(aq). In contrast, the speciation of Cu-II [2007PBa] and Pb-II [2009PBa] in seawater is dominated by the respective species MCO3(aq).
There is scope for additional high-quality measurements in the Cd2+ + H+ + CO32- system as the large uncertainties in the stability constants for the Cd2+-carbonato complexes significantly affect the speciation calculations
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