674 research outputs found
Exact and Asymptotic Conditions on Traveling Wave Solutions of the Navier-Stokes Equations
We derive necessary conditions that traveling wave solutions of the
Navier-Stokes equations must satisfy in the pipe, Couette, and channel flow
geometries. Some conditions are exact and must hold for any traveling wave
solution irrespective of the Reynolds number (). Other conditions are
asymptotic in the limit . The exact conditions are likely to be
useful tools in the study of transitional structures. For the pipe flow
geometry, we give computations up to showing the connection of our
asymptotic conditions to critical layers that accompany vortex structures at
high
Unified Theory of Acceptance and Use of Technology: A Synthesis and the Road Ahead
The unified theory of acceptance and use of technology (UTAUT) is a little over a decade old and has been used extensively in information systems (IS) and other fields, as the large number of citations to the original paper that introduced the theory evidences. In this paper, we review and synthesize the IS literature on UTAUT from September 2003 until December 2014, perform a theoretical analysis of UTAUT and its extensions, and chart an agenda for research going forward. Based on Weber’s (2012) framework of theory evaluation, we examined UTAUT and its extensions along two sets of quality dimensions; namely, the parts of a theory and the theory as a whole. While our review identifies many merits to UTAUT, we also found that the progress related to this theory has hampered further theoretical development in research into technology acceptance and use. To chart an agenda for research that will enable significant future work, we analyze the theoretical contributions of UTAUT using Whetten’s (2009) notion of cross-context theorizing. Our analysis reveals several limitations that lead us to propose a multi-level framework that can serve as the theoretical foundation for future research. Specifically, this framework integrates the notion of research context and cross-context theorizing with the theory evaluation framework to: 1) synthesize the existing UTAUT extensions across both the dimensions and the levels of the research context and 2) highlight promising research directions. We conclude with recommendations for future UTAUT-related research using the proposed framework
Recommended from our members
E-mail address categorization based on semantics of surnames
Surname (family name) analysis is used in geography to understand population origins, migration, identity, social norms and cultural customs. Some of these are supposedly evolved over generations. Surnames exhibit good statistical properties that can be used to extract information in names data set such as automatic detection of ethnic or community groups in names. An e-mail address, often contains surname as a substring. This containment may be full or partial. An e-mail address categorization based on semantics of surnames is the objective of this paper. This is achieved in two phases. First phase deals with surname representation and clustering. Here, a vector space model is proposed where latent semantic analysis is performed. Clustering is done using the method called averagelinkage method. In the second phase, an email is categorized as belonging to one of the categories (discovered in first phase). For this, substring matching is required, which is done in an efficient way by using suffix tree data structure. We perform experimental evaluation for the 500 most frequently occurring surnames in India and United Kingdom. Also, we categorize the e-mail addresses that have these surnames as substrings
Specific IgE Response to Purified and Recombinant Allergens in Latex Allergy
Background
In recent years, allergy to natural rubber latex has emerged as a major allergy among certain occupational groups and patients with underlying diseases. The sensitization and development of latex allergy has been attributed to exposure to products containing residual latex proteins. Although improved manufacturing procedures resulted in a considerable reduction of new cases, the potential risk for some patient groups is still great. In addition the prevalent cross-reactivity of latex proteins with other food allergens poses a major concern. A number of purified allergens and a few commercial kits are currently available, but no concerted effort was undertaken to evaluate them. Methods
We studied 11 purified latex allergens, Hev b 1 to Hev b 10, and Hev b 13 along with several crude allergen extracts and two commercial ImmunoCAP assays to evaluate specific IgE antibody in the sera from latex allergic patients and controls. Health care workers and spina bifida patients with clinical symptoms of latex allergy, spina bifida patients without latex allergy, and non-atopic health care workers have been studied. Results
The results suggest that Hev b 2, 5, 6, and 13 together identified over 80 percent health care workers with latex allergy, while Hev b 6 along with Hev b 1 or 3 detected specific IgE antibody in all sera studied from patients with spina bifida and latex allergy. The ImmunoCAP results using both Hev b 5 amplified and non-amplified closely agreed with the clinical diagnosis of latex allergy in health care workers and in spina bifida. Conclusion
Although the purified allergens and crude extracts reacted diversely with IgE from different patient groups, the results indicated that use of certain combinations of purified recombinant antigens will be useful in commercial kits or in in-house assays for detecting specific IgE antibody in the sera. The results suggest that a combination of Hev b 2, 3, 5, 6, and 13 together detected specific IgE in 80% of the sera from latex allergic patients. Both ImmunoCAPs correctly identified over 95% of latex allergic patients, however, showed reactivity with a few normal control subject
Atlantic Cod Piscidin and Its Diversification through Positive Selection
Piscidins constitute a family of cationic antimicrobial peptides that are thought to play an important role in the innate immune response of teleosts. On the one hand they show a remarkable diversity, which indicates that they are shaped by positive selection, but on the other hand they are ancient and have specific targets, suggesting that they are constrained by purifying selection. Until now piscidins had only been found in fish species from the superorder Acanthopterygii but we have recently identified a piscidin gene in Atlantic cod (Gadus morhua), thus showing that these antimicrobial peptides are not restricted to evolutionarily modern teleosts. Nucleotide diversity was much higher in the regions of the piscidin gene that code for the mature peptide and its pro domain than in the signal peptide. Maximum likelihood analyses with different evolution models revealed that the piscidin gene is under positive selection. Charge or hydrophobicity-changing amino acid substitutions observed in positively selected sites within the mature peptide influence its amphipathic structure and can have a marked effect on its function. This diversification might be associated with adaptation to new habitats or rapidly evolving pathogens
Dimer and N\'eel order-parameter fluctuations in the spin-fluid phase of the s=1/2 spin chain with first and second neighbor couplings
The dynamical properties at T=0 of the one-dimensional (1D) s=1/2
nearest-neighbor (nn) XXZ model with an additional isotropic
next-nearest-neighbor (nnn) coupling are investigated by means of the recursion
method in combination with techniques of continued-fraction analysis. The focus
is on the dynamic structure factors S_{zz}(q,\omega) and S_{DD}(q,\omega),
which describe (for q=\pi) the fluctuations of the N\'eel and dimer order
parameters, respectively. We calculate (via weak-coupling continued-fraction
analysis) the dependence on the exchange constants of the infrared exponent,
the renormalized bandwidth of spinon excitations, and the spectral-weight
distribution in S_{zz}(\pi,\omega) and S_{DD}(\pi,\omega), all in the
spin-fluid phase, which is realized for planar anisotropy and sufficiently
weak nnn coupling. For some parameter values we find a discrete branch of
excitations above the spinon continuum. They contribute to S_{zz}(q,\omega) but
not to S_{DD}(q,\omega).Comment: RevTex file (7 pages), 8 figures (uuencoded ps file) available from
author
Multiplexed, rapid detection of H5N1 using a PCR-free nanoparticle-based genomic microarray assay
<p>Abstract</p> <p>Background</p> <p>For more than a decade there has been increasing interest in the use of nanotechnology and microarray platforms for diagnostic applications. In this report, we describe a rapid and simple gold nanoparticle (NP)-based genomic microarray assay for specific identification of avian influenza virus H5N1 and its discrimination from other major influenza A virus strains (H1N1, H3N2).</p> <p>Results</p> <p>Capture and intermediate oligonucleotides were designed based on the consensus sequences of the matrix (M) gene of H1N1, H3N2 and H5N1 viruses, and sequences specific for the hemaglutinin (HA) and neuraminidase (NA) genes of the H5N1 virus. Viral RNA was detected within 2.5 hours using capture-target-intermediate oligonucleotide hybridization and gold NP-mediated silver staining in the absence of RNA fragmentation, target amplification, and enzymatic reactions. The lower limit of detection (LOD) of the assay was less than 100 fM for purified PCR fragments and 10<sup>3 </sup>TCID<sub>50 </sub>units for H5N1 viral RNA.</p> <p>Conclusions</p> <p>The NP-based microarray assay was able to detect and distinguish H5N1 sequences from those of major influenza A viruses (H1N1, H3N2). The new method described here may be useful for simultaneous detection and subtyping of major influenza A viruses.</p
Recommended from our members
Impact of Tobacco-Related Health Warning Labels across Socioeconomic, Race and Ethnic Groups: Results from a Randomized Web-Based Experiment
Background: The U.S. Family Smoking Prevention and Tobacco Control Act of 2009 requires updating of the existing text-only health warning labels on tobacco packaging with nine new warning statements accompanied by pictorial images. Survey and experimental research in the U.S. and other countries supports the effectiveness of pictorial health warning labels compared with text-only warnings for informing smokers about the risks of smoking and encouraging cessation. Yet very little research has examined differences in reactions to warning labels by race/ethnicity, education or income despite evidence that population subgroups may differ in their ability to process health information. The purpose of the present study was to evaluate the potential impact of pictorial warning labels compared with text-only labels among U.S. adult smokers from diverse racial/ethnic and socioeconomic subgroups. Methods/Findings: Participants were adult smokers recruited from two online research panels (n = 3,371) into a web-based experimental study to view either the new pictorial warnings or text-only warnings. Participants viewed the labels and reported their reactions. Adjusted regression models demonstrated significantly stronger reactions for the pictorial condition for each outcome salience (b = 0.62, p<.001); perceived impact (b = 0.44, p<.001); credibility (OR = 1.41, 95% CI = 1.22−1.62), and intention to quit (OR = 1.30, 95% CI = 1.10−1.53). No significant results were found for interactions between condition and race/ethnicity, education, or income. The only exception concerned the intention to quit outcome, where the condition-by-education interaction was nearly significant (p = 0.057). Conclusions: Findings suggest that the greater impact of the pictorial warning label compared to the text-only warning is consistent across diverse racial/ethnic and socioeconomic populations. Given their great reach, pictorial health warning labels may be one of the few tobacco control policies that have the potential to reduce communication inequalities across groups. Policies that establish strong pictorial warning labels on tobacco packaging may be instrumental in reducing the toll of the tobacco epidemic, particularly within vulnerable communities
Lignolytic Enzymes of a Mushroom Stereum ostrea Isolated from Wood Logs
Production of lignolytic enzymes by the mushroom fungus Stereum ostrea in liquid medium under conditions of vegetative growth was examined for 10 days in comparison to the reference culture Phanerochaete chrysosporium. Though growth and secretion of extracellular protein by S. ostrea were comparable to those of P. chrysosporium, yields of laccase enzyme by S. ostrea were higher than laccase titres of P. chrysosporium by more than 2 folds on the peak production time interval (IVth day of incubation). S. ostrea yielded titres of 25 units of laccase/ml as against 8.9 units of laccase/ml on the IVth day of incubation. Stereum ostrea also exhibited activities of other lignolytic enzymes, lignin peroxidase (LiP) and manganese peroxidase (MnP), higher than the reference culture. Growth of S. ostrea on the medium in the presence of Remazol orange 16 resulted in the decolourisation of dye, confirming the presence of lignolytic enzymes. S. ostrea appears to be a promising culture with complete lignolytic system
- …