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Search Results: 1 - 10 of 432637 matches for " S. F. Taylor "
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Small flow rate can supply inwardly migrating shortest-period planets
Taylor S.F.
EPJ Web of Conferences , 2013, DOI: 10.1051/epjconf/20134702003
Abstract: The number of exoplanets found with periods as short as one day and less was surprising given how fast these planets had been expected to migrate into the star due to the tides raised on the star by planets at such close distances. It has been seen as improbable that we would find planets in such a small final fraction of their lives [1]. The favored solution has been that the tidal dissipation is much weaker than expected, which would mean that the final infall would be a larger fraction of the planets’ life. We find no reason, however, to exclude the explanation that a small number of planets are continuously sent migrating inwards such that these planets indeed are in the last fraction of their lives. Following the observation that the distribution of medium planets disfavors tidal dissipation being significantly weaker than has been found from observations of binary stars [2], we now show that the numbers of planets in such a “flow” of excess planets migrating inwards is low enough that even depletion of the three-day pileup is a plausible source. Then the shortest period occurrence distribution would be shaped by planets continuously being sent into the star, which may explain the depletion of the pileup in the Kepler field relative to the solar neighborhood [3]. Because Kepler observes above the galactic plan, [3] suggested the Kepler field may include an older population of stars. The tidal dissipation strength in stars due to giant planets may be not greatly weaker than it is in binary stars.
Does the innermost occurrence distribution measure tidal dissipation, reveal a flow of giant planets, or both?
S. F. Taylor
Physics , 2012,
Abstract: The occurrence distribution of the shortest period giant exoplanets as found by Kepler show a drop-off that is a remarkable match to the drop-off expected by taking migration due to tides in the star. We present a comparison that can show the level of tidal dissipation (friction) as a function of the distribution of the ages of the star and planet system, with known dependencies on basic star and planet parameters. Use of this relation enables constraints to be put on the value of the tidal dissipation, constraints that will be improved as the distribution of the ages are determined. For the giant planets, this leads to an unexpectedly low value of tidal dissipation. This over-abundance of short period giant planets may be due to a continuing resupply of longer period giant planets migrating into a shorter period pileup, disrupting the presence of smaller planets along the way. Perhaps the occurrence distribution of close Neptune sized planets will better measure the tidal friction, while the distribution of Jupiter sized planets reveals that giant planets are more likely to complete a gradual migration into the star.
A Generalized Allosteric Mechanism for cis-Regulated Cyclic Nucleotide Binding Domains
Alexandr P. Kornev,Susan S. Taylor ,Lynn F. Ten Eyck
PLOS Computational Biology , 2008, DOI: 10.1371/journal.pcbi.1000056
Abstract: Cyclic nucleotides (cAMP and cGMP) regulate multiple intracellular processes and are thus of a great general interest for molecular and structural biologists. To study the allosteric mechanism of different cyclic nucleotide binding (CNB) domains, we compared cAMP-bound and cAMP-free structures (PKA, Epac, and two ionic channels) using a new bioinformatics method: local spatial pattern alignment. Our analysis highlights four major conserved structural motifs: 1) the phosphate binding cassette (PBC), which binds the cAMP ribose-phosphate, 2) the “hinge,” a flexible helix, which contacts the PBC, 3) the β2,3 loop, which provides precise positioning of an invariant arginine from the PBC, and 4) a conserved structural element consisting of an N-terminal helix, an eight residue loop and the A-helix (N3A-motif). The PBC and the hinge were included in the previously reported allosteric model, whereas the definition of the β2,3 loop and the N3A-motif as conserved elements is novel. The N3A-motif is found in all cis-regulated CNB domains, and we present a model for an allosteric mechanism in these domains. Catabolite gene activator protein (CAP) represents a trans-regulated CNB domain family: it does not contain the N3A-motif, and its long range allosteric interactions are substantially different from the cis-regulated CNB domains.
Measuring consumer preference for models of diabetes care delivered by pharmacists
Taylor S,Hourihan F,Krass I,Armour C
Pharmacy Practice (Granada) , 2009,
Abstract: Evaluation of a community pharmacy disease management program for type 2 diabetes, ‘SugarCare’, was conducted. Compared with the standard care offered by pharmacists, this enhanced program offered patients closer monitoring of blood glucose levels, counselling about lifestyle, etc. The SugarCare study was funded by a grant but if the care is to continue some other method of financing must be found. Objectives: This study aimed to measure consumer preference for one of the two types of care offered in the SugarCare study, the control/standard and the intervention/enhanced service; the strength of that preference; and participants’ willingness to pay (WTP) for their preferred care. Methods: SugarCare was a parallel groups, control versus intervention, repeated measures design conducted in three areas of NSW, Australia. Patients in the Intervention group (enhanced care) had one initial visit to the pharmacy with six follow up visits over approximately 9 months. At these visits blood glucose was downloaded and patient care issues addressed. At the end of the service, a survey instrument was mailed to the intervention and control participants who were asked to read it and then expect a telephone call within 2 weeks of receipt. Responses were requested over the phone and the survey instrument completed by the researcher. WTP data were collected using a modified payment card method.Results: Overall, 44/75 (59%; 47%-70% 95%CI) respondents expressed a preference for Scenario B (the enhanced care) while 31/75 (41%; 31%-52% 95%CI) preferred Scenario A (standard care) however, the difference was not statistically significant. The median maximum WTP was AUD10 for the enhanced care and AUD3.50 for the standard care (p<0.03).Conclusions: While the WTP values expressed were significantly higher for the enhanced care they did not match with the cost providing that diabetes care. Discrete choice analysis has the potential to overcome some of the difficulties encountered with the contingent valuation technique used here. Further research is required before WTP values such as these could be used with confidence to determine funding policy.
All bound states of NO_2 (J=0)
R. F. Salzgeber,V. Mandelshtam,Ch. Schlier,H. S. Taylor
Physics , 1997,
Abstract: We calculated all 2967 even and odd bound states of the adiabatic ground state of NO_2, using a modification of the ab initio potential energy surface of Leonardi et al. [J. Chem. Phys. 105, 9051 (1996)]. The calculation was performed by harmonic inversion of the Chebyshev correlation function generated by a DVR Hamiltonian in Radau coordinates. The relative error for the computed eigenenergies is $10^{-4}$ or better. Near the dissociation threshold the density of states is about 0.3cm$^{-1}$. Statistical analysis of the states shows some interesting structure of the rigidity parameter $\Delta_3$ as a function of energy.
The Interaction between the ISM and Star Formation in the Dwarf Starburst Galaxy NGC 4214
F. Walter,C. Taylor,S. Huettemeister,N. Scoville,V. McIntyre
Physics , 2000, DOI: 10.1086/318775
Abstract: We present the first interferometric study of the molecular gas in the metal-poor dwarf starburst galaxy NGC 4214. Our map of the 12CO(1-0) emission, obtained at the OVRO millimeter array, reveals an unexpected structural wealth. We detected three regions of molecular emission in the north-west (NW), south-east (SE) and centre of NGC 4214 which are in very different and distinct evolutionary stages (total molecular mass: 5.1 x 10^6 M_sun). These differences are apparent most dramatically when the CO morphologies are compared to optical ground based and HST imaging: massive star formation has not started yet in the NW region; the well-known starburst in the centre is the most evolved and star formation in the SE complex started more recently. We derive a star formation efficiency of 8% for the SE complex. Using high--resolution VLA observations of neutral hydrogen HI and our CO data we generated a total gas column density map for NGC 4214 (HI + H_2). No clear correlation is seen between the peaks of HI, CO and the sites of ongoing star formation. This emphasizes the irregular nature of dwarf galaxies. The HI and CO velocities agree well, so do the H-alpha velocities. In total, we cataloged 14 molecular clumps in NGC 4214. Our results from a virial mass analysis are compatible with a Galactic CO-to-H_2 conversion factor for NGC 4214 (lower than what is usually found in metal-poor dwarf galaxies).
辽宁热河生物群小龙虾化石形态特征及分类之甄别
沈炎彬,F.,R.,Schram,R.,S.,Taylor
科学通报 , 2000,
Abstract: 通过上侏罗统义县组61块龙虾标本的12种形态特征统计分析,分别论述了其构造分类意义.利用这些保存良好的新材料,对环足虾科(Cricoidoscelosidae)特征作了重要补充和修订.雄性第1腹足呈棒状,第2腹足无特化现象,是这一科的重要特征.从环足虾(Cricoidoscelosus)和古虫剌蛄属(Palaeocambarus)雌性都具有腹环沟构造来看,它们与虫剌蛄科的关系最密切.海相的化石原螯虾科(Protastacidae),在螯虾亚目(Astacida)中缺乏任何衍征鉴别特征,怀疑其是否属于真正的小龙虾(crayfish).
What Is Innovation? A Study of the Definitions, Academic Models and Applicability of Innovation to an Example of Social Housing in England  [PDF]
S. P. Taylor
Open Journal of Social Sciences (JSS) , 2017, DOI: 10.4236/jss.2017.511010
Abstract:
Throughout history innovation has been conceived, defined, interpreted and understood in different ways but what is it? This study looks at innovation starting with a brief history of innovation. It then looks at a sample of the multiple definitions that there are of innovation throughout the literature and from these develops a composite definition. From this composite definition, key components such as the creative process and academic models of creativity are looked at. The research then looks at the applicability of innovation through highlighting two studies carried out in England of innovation being applied within a social housing organisation. Through the application by a two dimensional typology of social innovation they had identified innovation being applied to new services and improvements to existing services. The research concludes that innovation can be identified with the creation of a new product or service or an improvement of an existing product or service.
Age distribution, polyps and rectal cancer in the Egyptian population-based cancer registry
Darlene Veruttipong,Amr S Soliman,Samuel F Gilbert,Taylor S Blachley
World Journal of Gastroenterology , 2012, DOI: 10.3748/wjg.v18.i30.3997
Abstract: AIM: To describe the clinical and epidemiologic profiles of the disease and to compare the findings with those generated from the previous hospital-based studies. METHODS: The Gharbiah cancer registry is the only population-based cancer registry in Egypt since 1998. We analyzed the data of all colorectal cancer patients included in the registry for the period of 1999-2007. All medical records of the 1364 patients diagnosed in Gharbiah during the study period were retrieved and the following information abstracted: age, residence, diagnosis date, grade, stage, topology, clinical characteristics, and histology variables. Egyptian census data for 1996 and 2006 were used to provide the general population’s statistics on age, sex, residence and other related demographic factors. In addition to age- and sex-specific incidence rate analyses, we analyze the data to explore the incidence distribution by rural-urban differences among the 8 districts of the province. We also compared the incidence rates of Gharbiah to the rates of the Surveillance Epidemiology and End Results (SEER) data of the United States. RESULTS: Over the 9 year-period, 1364 colorectal cancer cases were included. The disease incidence under age 40 years was relatively high (1.3/105) while the incidence in the age groups 40 and over was very low (12.0/105, 19.4/105 and 21.2/105 in the age groups 40-59 years, 60-69 years and > 70 years, respectively). The vast majority of tumors (97.2%) had no polyps and 37.2% of the patients presented with primary lesions in the rectum. Colorectal cancer was more common in patients from urban (55%) than rural (45%) areas. Regional differences in colon and rectal cancer incidence in the 8 districts of the study province may reflect different etiologic patterns in this population. The registry data of Egypt shows a slightly higher incidence of colorectal cancer than the United States in subjects under age 40 years. The results also shows significantly lower incidence of colorectal cancer in subjects over age 40 years compared to the same age group in the United States SEER. CONCLUSION: Low rate of polyps, low incidence in older subjects, and high rate of rectal cancer in Egypt. Future studies should explore clinical and molecular disease patterns.
Characterization of Power-to-Phase Conversion in High-Speed P-I-N Photodiodes
J. Taylor,S. Datta,A. Hati,C. Nelson,F. Quinlan,A. Joshi,S. Diddams
Physics , 2011, DOI: 10.1109/JPHOT.2011.2109703
Abstract: Fluctuations of the optical power incident on a photodiode can be converted into phase fluctuations of the resulting electronic signal due to nonlinear saturation in the semiconductor. This impacts overall timing stability (phase noise) of microwave signals generated from a photodetected optical pulse train. In this paper, we describe and utilize techniques to characterize this conversion of amplitude noise to phase noise for several high-speed (>10 GHz) InGaAs P-I-N photodiodes operated at 900 nm. We focus on the impact of this effect on the photonic generation of low phase noise 10 GHz microwave signals and show that a combination of low laser amplitude noise, appropriate photodiode design, and optimum average photocurrent is required to achieve phase noise at or below -100 dBc/Hz at 1 Hz offset a 10 GHz carrier. In some photodiodes we find specific photocurrents where the power-to-phase conversion factor is observed to go to zero.
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