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Search Results: 1 - 10 of 401619 matches for " M Bowen "
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Electronic Visualisation in Chemistry: From Alchemy to Art
Karl Harrison,Jonathan P. Bowen,Alice M. Bowen
Computer Science , 2013,
Abstract: Chemists now routinely use software as part of their work. For example, virtual chemistry allows chemical reactions to be simulated. In particular, a selection of software is available for the visualisation of complex 3-dimensional molecular structures. Many of these are very beautiful in their own right. As well as being included as illustrations in academic papers, such visualisations are often used on the covers of chemistry journals as artistically decorative and attractive motifs. Chemical images have also been used as the basis of artworks in exhibitions. This paper explores the development of the relationship of chemistry, art, and IT. It covers some of the increasingly sophisticated software used to generate these projections (e.g., UCSF Chimera) and their progressive use as a visual art form.
The Real Reason Why the Electron’s Bare g-Factor Is 2 Times Classical  [PDF]
Donald Bowen
Journal of Modern Physics (JMP) , 2016, DOI: 10.4236/jmp.2016.710109
Abstract: When analyzing an Electron’s orbit’s and movements, a “classical” bare g-factor of “1” must be used, but when analyzing just the Electron itself, a bare g-factor and gyromagnetic ratio of twice the “classical” value is needed to fit reality. Nobody has fully explained this yet. By examining the electromagnetic wave nature of the electron, it is possible to show a simple reason why its bare g-factor must be 2, without resorting to superluminal velocities or dismissing it as mystically intrinsic. A simple charged electromagnetic wave loop (CEWL) model of the electron that maintains the same electromagnetic wave nature as the high-energy photons from which electron-positron pairs form, will have exactly half of its energy in the form of magnetic energy who’s field lines are perpendicular to the direction of the charge rotation, which leads to the conclusion that only half of the electron’s electromagnetic mass is rotational mass, from which it is easy to calculate a bare g-factor of 2 using Feynman’s equation for the electron’s g-factor.
China’s Low-Carbon Economy Development and Carbon Finance Market Supervision Mechanism  [PDF]
Bowen Yang
Low Carbon Economy (LCE) , 2017, DOI: 10.4236/lce.2017.84008
Abstract: China planned to set maximum limits for carbon emissions in 2030. This means China will vigorously develop a low-carbon economy to achieve the low-carbon and sustainable transformation. Carbon financial regulation of multilayered embodies in mainly carbon emissions trading and carbon financial derivatives market is not only a secondary market regulation by the national development and reform commission. In reference to a more mature regional carbon emissions trading formation of information exchange, coordination function, inter-regional coordination mechanism to build legislative carbon trading by establishing cross-regional coordination committee. In this article, establishing a multi-level carbon financial regulatory framework, we can effectively regulate the trading of carbon emission rights and the trading of derivatives, thus providing legal protection for China’s low carbon economy.
Management of Business Challenges Among Small and Micro Enterprises in Nairobi-Kenya
M Bowen, M Morara, M Mureithi
KCA Journal of Business Management , 2009,
Abstract: Small and Micro Enterprises (SMEs) play an important economic role in many countries. In Kenya, for example the SME sector contributed over 50percent of new jobs created in 2005 but despite their significance, SMEs are faced with the threat of failure with past statistics indicating that three out five fail within the first few months. This study sought to understand how SMEs manage the challenges they face. These challenges seem to change (evolve) according to different macro and micro conditions. This study employed stratified random sampling to collect data from 198 businesses using interviews and questionnaires. The data was analysed descriptively and presented through figures, tables and percentages. The findings indicate that SMEs face the following challenges; competition among themselves and from large firms, lack of access to credit, cheap imports, insecurity and debt collection. Credit constraint seems to be easing up when compared to previous researches. Relevant training or education is positively related to business success. The SMEs have the following strategies to overcome the challenges; fair pricing, discounts and special offers, offering a variety of services and products, superior customer service and continuously improving quality of service delivery. The research concludes that business success is a consequence of embracing a mix of strategies.
New Pathways for Alimentary Mucositis
Joanne M. Bowen,Dorothy M. K. Keefe
Journal of Oncology , 2008, DOI: 10.1155/2008/907892
Abstract: Alimentary mucositis is a major dose-limiting toxicity associated with anticancer treatment. It is responsible for reducing patient quality of life and represents a significant economic burden in oncology. The pathobiology of alimentary mucositis is extremely complex, and an increased understanding of mechanisms and pathway interactions is required to rationally design improved therapies. This review describes the latest advances in defining mechanisms of alimentary mucositis pathobiology in the context of pathway activation. It focuses particularly on the recent genome-wide analyses of regimen-related mucosal injury and the identification of specific regulatory pathways implicated in mucositis development. This review also discusses the currently known alimentary mucositis risk factors and the development of novel treatments. Suggestions for future research directions have been raised.
The Physical Conditions and Metal Enrichment of Low-Redshift Interstellar and Intergalactic Media: The Benefits of High-Resolution Ultraviolet Spectra
Todd M. Tripp,David V. Bowen
Physics , 2003,
Abstract: To underscore the value of high spectral resolution for the study of low-z QSO absorption lines, we briefly present Space Telescope Imaging Spectrograph echelle data that demonstrate how increased resolution leads to dramatic improvement in line measurements. We show that even R = lambda/Delta lambda = 20,000 is insufficient for some measurements. The higher the resolution the better, but R ~ 50,000 is adequate for many outstanding questions about the IGM and the ISM of galaxies that can be probed using QSO absorption lines.
Chaotic stirring by a mesoscale surface-ocean flow
Edward R. Abraham,Melissa M. Bowen
Physics , 2002, DOI: 10.1063/1.1481615
Abstract: The horizontal stirring properties of the flow in a region of the East-Australian Current are calculated. A surface velocity field derived from remotely sensed data, using the Maximum Cross Correlation method, is integrated to derive the distribution of the finite-time Lyapunov exponents. For the region studied (between latitudes 36 S and 41 S and longitudes 150 E and 156 E) the mean Lyapunov exponent during 1997 is estimated to be 4 x 10^{-7} s^{-1}. This is in close agreement with the few other measurements of stirring rates in the surface ocean which are available. Recent theoretical results on the multifractal spectra of advected reactive tracers are applied to an analysis of a sea-surface temperature image of the study region. The spatial pattern seen in the image compares well with the pattern seen in an advected tracer with a first-order response to changes in surface forcing. The response timescale is estimated to be 20 days.
Luteal regression: a redefinition of the terms
Jennifer M Bowen-Shauver, Carlos M Telleria
Reproductive Biology and Endocrinology , 2003, DOI: 10.1186/1477-7827-1-28
Abstract: The overall process of luteal regression has been referred to by a variety of terms over the last several decades. In Table 1, we show the results of a cursory MEDLINE/PubMed search on luteal regression performed in November of 2002, which reveals that the most frequently utilized term for this process is "luteolysis," followed by "luteal regression," and then, to a lesser extent, by "functional luteolysis" and "structural luteolysis." Other terms, such as "luteal involution," "functional luteal regression," or "structural luteal regression" lag far behind in usage. The necessity of using several keywords to search for information on luteal regression is illustrated by the fact that in our sample MEDLINE/PubMed search, only 47% of the manuscripts retrieved using the keyword "luteal regression" were also retrieved when using the keyword "luteolysis." This inconsistency in terminology can result in serious under-retrieval and under-citation of papers using less popular keywords.To quote Rossdale and Cox in their communication entitled Terminology: a mark of scientific progress [1]: "Scientific terminology must be as exact as is possible within the state of knowledge available." As our knowledge of the molecular mechanisms participating in the process of luteal regression evolves, some of the commonly used terms cited above have been rendered obsolete, inappropriate, and even incorrect. The foremost of these is "luteolysis," still one of the most common terms used to define the process of luteal regression, most probably because it is listed among Medical Subject Headings (MeSH), and, therefore, used most frequently. MeSH is the U.S. National Library of Medicine's controlled vocabulary used for indexing articles in PubMed. MeSH terminology provides a consistent way to retrieve information that may use different terminology for the same concepts. In MeSH, "luteolysis" is defined as "degradation of corpus luteum" and further described as "...characterized by the involuti
Repulsion forces of superplasticizers on ground granulated blast furnace slag in alkaline media, from AFM measurements to rheological properties
Palacios, M.,Bowen, P.,Kappl, M.,Butt, H. J.
Materiales de Construccion , 2012,
Abstract: The electrostatic and steric repulsion induced by different superplasticizers on ground granulated blast furnace slag in alkaline media have been studied. The superplasticizers were sulfonated naphthalene, sulfonated melamine, vinyl copolymer, and polycarboxylate- based admixtures. With these superplasticizers the slag suspensions had negative zeta potentials, ranging from -3 to -10 mV. For the first time the adsorbed layer thicknesses for superplasticizers on slag using colloidal probe atomic force microscopy has been measured. To model the interparticle force interactions an effective Hamaker constant was computed from dielectric properties measured on a dense slag sample produced by spark plasma sintering. The obtained results conclude that the dispersion mechanism for all the superplasticizers studied in the present work is mainly dominated by the steric repulsion. Results were then used in a yield stress model, YODEL, to predict the yield stress with and without the superplasticizers. Predictions of the yield stress agreed well with experimental results. En este trabajo se ha estudiado la repulsión electrostática y estérica inducida por diferentes aditivos superplastificantes en sistemas de escoria de horno alto en medios alcalinos. Se han estudiado aditivos superplastificantes basados en naftaleno, melamina, copolímeros vinílicos y basados en policarboxilato. Estos aditivos inducen en la escoria un potencial zeta negativo, entre -3 y -10 mV. Por primera vez, se ha determinado el grosor de la capa de aditivo adsorbido sobre la escoria mediante microscopía de fuerzas atómicas (AFM). Para modelizar las fuerzas de interacción entre partículas, se ha determinado la constante efectiva de Hamaker de la escoria a partir de las propiedades dieléctricas de una muestra de escoria obtenida mediante sinterización spark plasma sintering. Los resultados obtenidos concluyen que el mecanismo de dispersión de los superplastificantes estudiados en este trabajo está gobernado fundamentalmente por la repulsión estérica. Utilizando el modelo YODEL se ha podido predecir el esfuerzo de cizalla umbral de sistemas de escoria con y sin superplastificantes. Los resultados calculados están de acuerdo con los valores de esfuerzo de cizalla determinados experimentalmente.
Homopolymeric tracts represent a general regulatory mechanism in prokaryotes
Renato H Orsi, Barbara M Bowen, Martin Wiedmann
BMC Genomics , 2010, DOI: 10.1186/1471-2164-11-102
Abstract: We show here that prokaryotes evolved to include homopolymeric tracts (HTs) within coding genes as a system that allows for efficient gene inactivation. Analyses of 81 bacterial and 18 archaeal genomes showed that poly(A) and poly(T) HTs are overrepresented in these genomes and preferentially located at the 5' end of coding genes. Location of HTs at the 5' end is not driven by a preferential placement of aminoacids encoded by the AAA and TTT codons at the N-terminal of proteins. The inlA gene of the pathogen L. monocytogenes was used as a model to further study the role of HTs in reversible gene inactivation. In a number of L. monocytogenes strains, inlA harbors a 5' poly(A) HT, which regularly shows frameshift mutation leading to expression of a truncated 8 aa InlA protein. Translational fusions of the inlA 5' end allowed us to estimate that the frequency of variation in this HT is about 1,000 fold higher than the estimated average point mutation frequency.As frameshift mutations in HTs can occur at high frequencies and enable efficient gene inactivation, hypermutable HTs appear to represent a universal system for regulation of gene expression in prokaryotes. Combined with other studies indicating that HTs also enable rapid diversification of both coding and regulatory genetic sequences in eukaryotes, our data suggest that hypermutable HTs represent a general and rapid evolutionary mechanism facilitating adaptation and gene regulation across diverse organisms.The ability to adapt to different environments is critical for all living organisms. Mechanisms of adaptation range from rapid changes in gene transcription to stable genetic changes that occur over an evolutionary time frame. Phase variation is a specific adaptive mechanism that typically involves a rapid switch between two different states (ON and OFF) to enable individual microbial cells to vary expression of proteins. Bacterial pathogens such as Escherichia coli, Neisseria meningitides and Helicobacter pyl
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