121,982 research outputs found
A Comparison of Methods for Determining the Time Step When Propagating with the Lanczos Algorithm
No full textTo use the short iterative Lanczos algorithm to solve the time-dependent Schroedinger equation, one must choose, for a given Lanczos space size, a time step. We compare the derivation of the well-known Lubich and Hochbruck time step from SIAM J. Numer. Anal. 34 (1997) 1911 with the a priori time step we proposed in Mohankumar and Carrington (MC) Comput. Phys. Commun., 181 (2010) 1859 and demonstrate that the MC time step is somewhat larger, i.e., that the MC error bound is tighter. In addition, we use the MC approach to derive an error bound and time step for imaginary time propagation. The error bound we derive is much tighter than the error bound of Stewart and Leyk
[Cu(N^N)(P^P)]+ complexes with 2,2':6',2''-terpyridine ligands as the N^N domain
No full textThe first examples of [Cu(N^N)(POP)]+ complexes (POP = bis(2-(diphenylphosphino)phenyl)ether) in which the N^N domain is a 2,2′:6′,2′′-terpyridine (tpy) ligand have been prepared and characterized; N^N = tpy, 5,5′′-dimethyl-2,2′:6′,2′′-terpyridine (1), 4′-(4-tolyl)-2,2′:6′,2′′-terpyridine (2), 4′-(4-npropoxyphenyl)-2,2′:6′,2′′-terpyridine (3) and 4′-(4-nbutoxyphenyl)-2,2′:6′,2′′-terpyridine (4). In solution, the tpy domain in each [Cu(N^N)(POP)][PF6] complex is C2-symmetric, consistent with either tridentate coordination or a low energy dynamic process involving bidentate ligands; for [Cu(2)(POP)][PF6] and [Cu(4)(POP)][PF6], the 1H NMR spectra showed negligible change between 295 and 210 K. The single crystal structures of [Cu(tpy)(POP)][PF6] and [Cu(4)(POP)][PF6] are presented. The asymmetric unit of [Cu(tpy)(POP)][PF6] contains two independent cations; in one the tpy ligand is tridentate and in the other, it is bidentate with the non-coordinated pyridine ring facing the Cu atom (Cu⋯N = 3.146(1) Å). In contrast, the solid-state structure of [Cu(4)(POP)][PF6] features a [Cu(4)(POP)]+ cation containing a bidentate tpy-domain with the non-coordinated pyridine ring oriented with the N-atom facing away from the Cu atom; this conformation may be associated with inter-cation N⋯HC non-classical hydrogen bonds. The photophysical properties of [Cu(N^N)(POP)][PF6] with N^N = tpy or 1–4 are described. In the solid state at room temperature, the compounds are poorly emissive. In solution, the emission behaviour is consistent with ligand dissociation. This is supported by 1H and 31P NMR spectroscopic data which show POP and [Cu(POP)2]+ in solutions of aged samples; mass spectrometric data are consistent with the formation of [Cu(N^N)2]2+ in these samples
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Performance Evaluation of Scheduling Algorithms with Different MIMO Techniques in LTE Systems
No full textMIMO techniques are used in Wireless Broadband Access (BWA)
networks to maximize spectrum efficiency and minimize the bit
error rate. LTE is one such BWA network which has adopted
MIMO techniques in both the uplink and downlink along with
Radio Resource Management (RRM) aspects like scheduling
to improve the data rate. Scheduling is mainly concerned with allocating the available radio resources among the users depending upon the metrics such as Quality of Service (QoS) requirements of users, channel conditions etc. Hence in this paper, an attempt is made to study and compare the performance of scheduling algorithms (RR, PF, MT and BET) with MIMO techniques such
as SISO, SIMO, SFBC and OLSM for Constant Bit Rate (CBR)
traffic scenario. The performance metrics used are average throughput and average delay
The vanishing author in computer-generated works: a critical analysis of recent Australian case law
No full textAbstract
The use of software is ubiquitous in the creation of many copyright works, yet the requirement in copyright law that every work have a human author who engages in independent intellectual effort means that its use may prevent copyright subsistence. Several recent Australian cases have refocused attention on authorship as an essential criterion of copyright subsistence, and these cases suggest that much computer-produced output may be authorless and thus lack copyright protection. This article, the first in a two-part series, analyses how each case deals with the question of authorship of computer-produced works and why the use of software diminishes copyright protection for a significant number of computer-generated works. The article critiques the application of conventional notions of human authorship developed in the pre-computer age to modern productions and suggests alternative approaches to authorship that satisfy both the major objectives of copyright policy and the need to adapt to the computer age. The article argues that, without a broader judicial approach to authorship of computer-generated works, Parliament must remedy the lacuna in protection for these ‘authorless’ works. Possible solutions for reform are suggested. In a forthcoming article, the author comprehensively examines those reform proposals
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Microfluidics-Based Drying–Wetting Cycles to Investigate Phase Transitions of Small Molecules Solutions
No full textDrying–wetting cycles play a crucial role in the investigation of the origin of life as processes that both concentrate and induce the supramolecular assembly and polymerization of biomolecular building blocks, such as nucleotides and amino acids. Here, we test different microfluidic devices to study the dehydration–hydration cycles of the aqueous solutions of small molecules, and to observe, by optical microscopy, the insurgence of phase transitions driven by self-assembly, exploiting water pervaporation through polydimethylsiloxane (PDMS). As a testbed, we investigate solutions of the chromonic dye Sunset Yellow (SSY), which self-assembles into face-to-face columnar aggregates and produces nematic and columnar liquid crystal (LC) phases as a function of concentration. We show that the LC temperature–concentration phase diagram of SSY can be obtained with a fair agreement with previous reports, that droplet hydration–dehydration can be reversibly controlled and automated, and that the simultaneous incubation of samples with different final water contents, corresponding to different phases, can be implemented. These methods can be further extended to study the assembly of diverse prebiotically relevant small molecules and to characterize their phase transitions
HOXA1-stimulated oncogenicity is mediated by selective upregulation of components of the p44/42 MAP kinase pathway in human mammary carcinoma cells
No full textExpression of homeobox A1 (HOXA1) results in oncogenic transformation of immortalized human mammary epithelial cells with aggressive tumor formation in vivo. However, the mechanisms by which HOXA1 mediates oncogenic transformation is not well defined. To identify molecules that could potentially be involved in HOXA1-mediated oncogenic transformation, microarray analysis was utilized to characterize and compare the gene expression pattern in response to forced expression or depletion of HOXA1 in human mammary carcinoma cells. Gene expression profiling identified that genes involved in the p44/42 mitogen-activated protein (MAP) kinase activation pathway (GRB2, MAP kinase kinase (MEK1) and SDFR1) or p44/42 MAP kinase-regulated genes (IER3, EPAS1, PCNA and catalase) are downstream expression targets of HOXA1. Forced expression of HOXA1 increased GRB2 and MEK1 mRNA and protein expression and increased p44/42 MAP kinase phosphorylation, activity and Elk-1-mediated transcription. Use of a MEK1 inhibitor demonstrated that increased p44/42 MAP kinase activity is required for the HOXA1-mediated increase in cell proliferation, survival, oncogenicity and oncogenic transformation. Thus, modulation of the p44/42 MAP kinase pathway is one mechanism by which HOXA1 mediates oncogenic transformation of the human mammary epithelial cell
Dissipative Range Scaling of Higher Order Structure Functions for Velocity and Passive Scalars
No full textDifferently to Kolmogorov's second similarity hypothesis, we find that the 2n-th order velocity and scalar structure functions scale with n-th order moment of the energy dissipation and the scalar dissipation, respectively. The origins of this scaling are analyzed by the transport equations of the fourth order velocity and scalar increment moments and by direct numerical simulations
- …
