7,458 research outputs found
The Molluscan Fauna of the Florida Middle Grounds with Comments on its Zoogeographical Affinities
Recent studies have indicated that the Gulf of Mexico is bounded by a discontinual series of hard substrates which support faunal and floral assemblages of both temperate and tropical origins. This substrate distribution has had a significant impact on molluscan fauna in the Gulf of Mexico. An investigation of the molluscan fauna of the Florida Middle Grounds has produced 75 species associated with this high relief substrate which is also characterized by hermatypic corals. Although the molluscan fauna is comprised of forms which are predominantly Caribbean eurythermic and Caribbean Restricted (76%) which is similar in composition to the West Flower Garden Bank of Texas, their species composition is quite dissimilar (only 23% similarity). For these and other reasons, it is proposed that the zoogeographic status of the Gulf of Mexico should be seriously reconsidered by specialists in other faunal groups
An Analytical Construction of the SRB Measures for Baker-type Maps
For a class of dynamical systems, called the axiom-A systems, Sinai, Ruelle
and Bowen showed the existence of an invariant measure (SRB measure) weakly
attracting the temporal average of any initial distribution that is absolutely
continuous with respect to the Lebesgue measure. Recently, the SRB measures
were found to be related to the nonequilibrium stationary state distribution
functions for thermostated or open systems. Inspite of the importance of these
SRB measures, it is difficult to handle them analytically because they are
often singular functions. In this article, for three kinds of Baker-type maps,
the SRB measures are analytically constructed with the aid of a functional
equation, which was proposed by de Rham in order to deal with a class of
singular functions. We first briefly review the properties of singular
functions including those of de Rham. Then, the Baker-type maps are described,
one of which is non-conservative but time reversible, the second has a
Cantor-like invariant set, and the third is a model of a simple chemical
reaction . For the second example, the
cases with and without escape are considered. For the last example, we consider
the reaction processes in a closed system and in an open system under a flux
boundary condition. In all cases, we show that the evolution equation of the
distribution functions partially integrated over the unstable direction is very
similar to de Rham's functional equation and, employing this analogy, we
explicitly construct the SRB measures.Comment: 53 pages, 10 figures, to appear in CHAO
Networks Fighting Nicotine: Will Visitors to a Tobacco Cessation Website Engage in an Online Support Community?
Background: Online tobacco cessation social networks may influence effectiveness of Web-Assisted Tobacco Interventions (WATIs). Purpose: To understand characteristics and quit rates of WATI participants navigating to BecomeAnEx.org, an online cessation network. Methods: We recruited 759 smokers to a WATI (decide2quit.org), through in-person primary care and dental office referrals and Google ads. We used online surveys to gather data on sociodemographics, tobacco use, and readiness to quit. Smokers were able to navigate online from the WATI to an online social network supporting cessation (BecomeAnEx.org). We identified visitors to and registrants with BecomeAnEx.org, examining associations between BecomeAnEx.org use and sociodemographic characteristics, patterns of WATI use and likelihood of tobacco cessation. Results: One-quarter (26.0%) of WATI users visited BecomeAnEx.org ; 7.5% registered. BecomeAnEx.org visitors were more likely than nonvisitors to be female (73.0% vs. 62.6% p\u3c0.01) and more likely to have visited a smoking cessation website before (43.9% vs 17.4%, p\u3c.01). Registrants were more likely to engage in other WATI tools including e-mails to trained tobacco specialists (68.4% vs 28.8). No significant association was found between BecomeAnEx.org use (visiting or registration) and tobacco cessation. Conclusions: BecomeAnEx.org navigation from our WATI was limited, attracting those already inclined toward online cessation tools. Future studies must explore whether online cessation social networks may have additional benefits if designed to attract larger audiences
Permanent draft genome sequence of Vibrio tubiashii strain NCIMB 1337 (ATCC19106).
This is the final version of the article. Available from BioMed Central via the DOI in this record.Vibrio tubiashii NCIMB 1337 is a major and increasingly prevalent pathogen of bivalve mollusks, and shares a close phylogenetic relationship with both V. orientalis and V. coralliilyticus. It is a Gram-negative, curved rod-shaped bacterium, originally isolated from a moribund juvenile oyster, and is both oxidase and catalase positive. It is capable of growth under both aerobic and anaerobic conditions. Here we describe the features of this organism, together with the draft genome and annotation. The genome is 5,353,266 bp long, consisting of two chromosomes, and contains 4,864 protein-coding and 86 RNA genes.We wish to thank i-G Peninsula (Prospect Place, the Hoe, Plymouth, Devon, UK) for providing funding for this project, and NBAF Edinburgh for performing the sequencing
Attenuation of Experimental Aortic Aneurysm Formation in P-Selectin Knockout Mice
The aim of this study was to determine the role of P-selectin, an adhesion molecule found on the surface of activated platelets and endothelial cells during experimental aortic aneurysm formation. Infrarenal abdominal aortas of C57 black wild-type (WT) mice and P-selectin knockout (PKO) mice were measured in situ and then perfused with porcine pancreatic elastase (0.332 U mL). Whole blood was drawn from the tail artery on day 2 pre-perfusion to determine total and differential white blood cell (WBC) counts. On day 14 postperfusion, aortic diameters (AD) of WT mice ( N 19) and PKO mice ( N 9) were measured. An aortic aneurysm was defined as a 100 or greater increase in AD from pre-perfusion measurement. Immunohistochemistry, including H&E, trichrome and von Gieson staining, was performed on harvested aortic tissue. Statistical analysis was performed by t -test and Fisher's exact test. There were no significant differences in peripheral leukocyte counts at baseline between the two groups. WT mice had significantly larger AD compared to PKO mice at day 14 postperfusion (116 vs. 38 , P < 0.001). Aortic aneurysm penetrance was 52 in WT mice, while 0 ( P 0.01) of PKO mice formed aneurysms. On histologic examination, WT mouse aortas were associated with a significant inflammatory response and degradation of elastin and collagen fibers, while PKO mouse aortas lacked signs of inflammation or vessel wall injury. P-selectin deficiency attenuates aneurysm formation in the elastase aortic perfusion model. This was associated with a blunting of the inflammatory response and preserved vessel wall intergrity following elastase perfusion in the P-selectin knockout mice. Further investigation to elucidate the independent contributions of endothelial cell and platelet P-selectin in experimental aortic aneurysm formation is required.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73125/1/annals.1383.014.pd
Secure Asynchronous Communication Between Smokers and Tobacco Treatment Specialists: Secondary Analysis of a Web-Assisted Tobacco Intervention in the QUIT-PRIMO and National Dental PBRN Networks
BACKGROUND: Within a web-assisted tobacco intervention, we provided a function for smokers to asynchronously communicate with a trained tobacco treatment specialist (TTS). Previous studies have not attempted to isolate the effect of asynchronous counseling on smoking cessation.
OBJECTIVE: This study aimed to conduct a semiquantitative analysis of TTS-smoker communication and evaluate its association with smoking cessation.
METHODS: We conducted a secondary analysis of data on secure asynchronous communication between trained TTSs and a cohort of smokers during a 6-month period. Smokers were able to select their preferred TTS and message them using a secure web-based form. To evaluate whether the TTS used evidence-based practices, we coded messages using the Motivational Interviewing Self-Evaluation Checklist and Smoking Cessation Counseling (SCC) Scale. We assessed the content of messages initiated by the smokers by creating topical content codes. At 6 months, we assessed the association between smoking cessation and the amount of TTS use and created a multivariable model adjusting for demographic characteristics and smoking characteristics at baseline.
RESULTS: Of the 725 smokers offered asynchronous counseling support, 33.8% (245/725) messaged the TTS at least once. A total of 1082 messages (TTSs: 565; smokers 517) were exchanged between the smokers and TTSs. The majority of motivational interviewing codes were those that supported client strengths (280/517, 54.1%) and promoted engagement (280/517, 54.1%). SCC code analysis showed that the TTS provided assistance to smokers if they were willing to quit (247/517, 47.8%) and helped smokers prepare to quit (206/517, 39.8%) and anticipate barriers (197/517, 38.1%). The majority of smokers\u27 messages discussed motivations to quit (234/565, 41.4%) and current and past treatments (talking about their previous use of nicotine replacement therapy and medications; 201/565, 35.6%). The majority of TTS messages used behavioral strategies (233/517, 45.1%), offered advice on treatments (189/517, 36.5%), and highlighted motivations to quit (171/517, 33.1%). There was no association between the amount of TTS use and cessation. In the multivariable model, after adjusting for gender, age, race, education, readiness at baseline, number of cigarettes smoked per day at baseline, and the selected TTS, smokers messaging the TTS one or two times had a smoking cessation odds ratio (OR) of 0.8 (95% CI 0.4-1.4), and those that messaged the TTS more than two times had a smoking cessation OR of 1.0 (95% CI 0.4-2.3).
CONCLUSIONS: Our study demonstrated the feasibility of using asynchronous counseling to deliver evidence-based counseling. Low participant engagement or a lack of power could be potential explanations for the nonassociation with smoking cessation. Future trials should explore approaches to increase participant engagement and test asynchronous counseling in combination with other approaches for improving the rates of smoking cessation. Phillips, Jessica H Williams, Sarah L Cutrona, Midge N Ray, Gregg H Gilbert, Thomas K Houston, QUITPRIMO, National Dental PBRN Collaborative Group. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 06.05.2020
Practices participating in a dental PBRN have substantial and advantageous diversity even though as a group they have much in common with dentists at large
<p>Abstract</p> <p>Background</p> <p>Practice-based research networks offer important opportunities to move recent advances into routine clinical practice. If their findings are not only generalizable to dental practices at large, but can also elucidate how practice characteristics are related to treatment outcome, their importance is even further elevated. Our objective was to determine whether we met a key objective for The Dental Practice-Based Research Network (DPBRN): to recruit a diverse range of practitioner-investigators interested in doing DPBRN studies.</p> <p>Methods</p> <p>DPBRN participants completed an enrollment questionnaire about their practices and themselves. To date, more than 1100 practitioners from the five participating regions have completed the questionnaire. The regions consist of: Alabama/Mississippi, Florida/Georgia, Minnesota, Permanente Dental Associates, and Scandinavia (Denmark, Norway, and Sweden). We tested the hypothesis that there are statistically significant differences in key characteristics among DPBRN practices, based on responses from dentists who participated in DPBRN's first network-wide study (n = 546).</p> <p>Results</p> <p>There were statistically significant, substantive regional differences among DPBRN-participating dentists, their practices, and their patient populations.</p> <p>Conclusion</p> <p>Although as a group, participants have much in common with practices at large; their substantial diversity offers important advantages, such as being able to evaluate how practice differences may affect treatment outcomes, while simultaneously offering generalizability to dentists at large. This should help foster knowledge transfer in both the research-to-practice and practice-to-research directions.</p
E-government adoption: A cultural comparison
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ Springer Science + Business Media, LLC 2008.E-government diffusion is an international phenomenon. This study compares e-government adoption in the U.K. to adoption in the U.S. In particular, this study seeks to determine if the same factors are salient in both countries. Several studies have explored citizen acceptance of e-government services in the U.S. However, few studies have explored this phenomenon in the U.K. To identify the similarities and differences between the U.K. and the U.S. a survey is conducted in the U.K. and the findings are compared to the literature that investigates diffusion in the U.S. This study proposes a model of e-government adoption in the U.K. based on salient factors in the U.S. A survey is administered to 260 citizens in London to assess the importance of relative advantage, trust and the digital divide on intention to use e-government. The results of binary logistic regression indicate that there are cultural differences in e-government adoption in the U.K. and the U.S. The results indicate that of the prevailing adoption constructs, relative advantage and trust are pertinent in both the U.S. and the U.K., while ICT adoption barriers such as access and skill may vary by culture. Implications for research and practice are discussed
Magnetic Field Dependence of Macroscopic Quantum Tunneling and Coherence of Ferromagnetic Particle
We calculate the quantum tunneling rate of a ferromagnetic particle of diameter in a magnetic field of arbitrary angle. We consider the
magnetocrystalline anisotropy with the biaxial symmetry and that with the
tetragonal symmetry. Using the spin-coherent-state path integral, we obtain
approximate analytic formulas of the tunneling rates in the small -limit for the magnetic field normal to the easy axis (), for the field opposite to the initial easy axis (),
and for the field at an angle between these two orientations (). In addition, we obtain numerically the tunneling rates for
the biaxial symmetry in the full range of the angle of the magnetic
field (), for the values of \epsilon =0.01 and
0.001.Comment: 25 pages of text (RevTex) and 4 figures (PostScript files), to be
published in Phys. Rev.
Characterization of Nucleotide Misincorporation Patterns in the Iceman's Mitochondrial DNA
BACKGROUND: The degradation of DNA represents one of the main issues in the genetic analysis of archeological specimens. In the recent years, a particular kind of post-mortem DNA modification giving rise to nucleotide misincorporation ("miscoding lesions") has been the object of extensive investigations. METHODOLOGY/PRINCIPAL FINDINGS: To improve our knowledge regarding the nature and incidence of ancient DNA nucleotide misincorporations, we have utilized 6,859 (629,975 bp) mitochondrial (mt) DNA sequences obtained from the 5,350-5,100-years-old, freeze-desiccated human mummy popularly known as the Tyrolean Iceman or Otzi. To generate the sequences, we have applied a mixed PCR/pyrosequencing procedure allowing one to obtain a particularly high sequence coverage. As a control, we have produced further 8,982 (805,155 bp) mtDNA sequences from a contemporary specimen using the same system and starting from the same template copy number of the ancient sample. From the analysis of the nucleotide misincorporation rate in ancient, modern, and putative contaminant sequences, we observed that the rate of misincorporation is significantly lower in modern and putative contaminant sequence datasets than in ancient sequences. In contrast, type 2 transitions represent the vast majority (85%) of the observed nucleotide misincorporations in ancient sequences. CONCLUSIONS/SIGNIFICANCE: This study provides a further contribution to the knowledge of nucleotide misincorporation patterns in DNA sequences obtained from freeze-preserved archeological specimens. In the Iceman system, ancient sequences can be clearly distinguished from contaminants on the basis of nucleotide misincorporation rates. This observation confirms a previous identification of the ancient mummy sequences made on a purely phylogenetical basis. The present investigation provides further indication that the majority of ancient DNA damage is reflected by type 2 (cytosine-->thymine/guanine-->adenine) transitions and that type 1 transitions are essentially PCR artifacts
- …