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Polarization variability arising from clumps in the winds of Wolf-Rayet stars

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Chinese Journal of Astronomy and Astrophysics 2009年第5期9卷 558-576页

作者： Qing-Kang Li Joseph E Cassinelli john C. Brown richard Ignace Department of Astronomy Beijing Normal University Beijing 100875 China Department of Astronomy University of Wisconsin-Madison 53711 USA Department of Physics and Astronomy University of Glasgow Glasgow G12 8QQ Scotland UK Department of Physics and Astronomy Eastern Tennessee State University USA

Polarimetric and photometric variability of Wolf-Rayet （WR） stars as caused by clumps in the winds is revisited. In our model, which is improved from Li et al., radial expansion of the thickness is accounted for, but we retain dependence on the β velocity law and stellar occultation effects. We again search for parameters that can yield results consistent with observations in regards to the mean polarization p, the ratio R = σp/σphot of polarimetric to photometric variability and the volume filling factor fV. Clump generation and spatial distribution are randomized by the Monte Carlo method so as to produce clumps which are, in the mean, distributed uniformly in space and have time intervals that obey a Gaussian distribution. The generated clumps move radially outward with a velocity law determined by a β index, and the angular size of clumps is assumed to be fixed. By fitting the observed σp/σphot and the volume filling factor fv, clump velocity taw index β （- 2） and clump ejection rate .N （- 1） are inferred, and are found to be well constrained. In addition, the subpeak features of broad emission lines seem to support the clump ejection rate. Meanwhile, the fraction of total mass loss rate that is contained in clumps is obtained by fitting observed polarization. We conclude that this picture of the clumps＇ properties produces a valuable diagnostic of WR wind structure.

关键词： stars mass loss -- stars Wolf-Rayet -- stars winds, outflows

Explicit and Parameterized Episodes of Warm-Season Precipitation over the Continental United States

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Advances in Atmospheric Sciences 2006年第1期23卷 91-105页

作者： Mitchell W. MONCRIEFF john D. TUTTLE richard E. CARBONE National Center for Atmospheric Research BoulderColorado 80307-3000U. S. A.

This paper describes explicit and parameterized simulations of midsummer precipitation over the continental United States for two distinct episodes： moderate large-scale forcing and weak forcing. The objective is to demonstrate the capability of explicit convection at currently affordable grid-resolution and compare it with parameterized realizations. Under moderate forcing, 3-kin grid-resolution explicit simulations represent rainfall coherence remarkably well. The observed daily convective generation near the Continental Divide and the subsequent organization and propagation are reproduced qualitatively. The propagation speed, zonal extent and duration of the rainfall streaks compare favorably with their observed counterparts, although the streak frequency is underestimated. The simulations at -10-km grid-resolution applying conventional convective parameterization schemes also replicate reasonably well the diurnal convective regeneration in moderate forcing. The performance of the 3-km grid-resolution model demonstrates the potential of -1-km-resolution explicit cloud-resolving models for the prediction of warm season precipitation for moderately forced environments. In weak forcing conditions, however, predictions of precipitation coherence and diurnal variability are much poorer. This suggests that an even finer resolution explicit model is required to adequately treat convective initiation and upscale organization typical of the warm season over the continental U.S.

关键词： warm-season precipitation explicit simulation convective parameterization

Low-loss microwave photonics links using hollow core fibres

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Light(Science & Applications) 2022年第8期11卷 1891-1902页

作者： Xi Zhang Zitong Feng David Marpaung Eric Numkam Fokoua Hesham Sakr john richard Hayes Francesco Poletti David john richardson Radan Slavík Optoelectronics Research Centre University of SouthamptonSouthamptonSO171BJUK Laser Physics and Nonlinear Optics Group Faculty of Science and TechnologyMESA+Institute for NanotechnologyUniversity of TwenteEnschede7500 AEThe Netherlands

There are a host of applications in communications, sensing, and science, in which analogue signal transmission is preferred over today’s dominant digital transmission. In some of these applications, the advantage is in lower cost, while in others, it lies in superior performance. However, especially for longer analogue photonics links (up to 10 s of km), the performance is strongly limited by the impairments arising from using standard single-mode fibres (SSMF). Firstly, the three key metrics of analogue links (loss, noise figure, and dynamic range) tend to improve with received power, but this is limited by stimulated Brillouin scattering in SSMF. Further degradation is due to the chromatic dispersion of SSMF, which induces radio-frequency (RF) signal fading, increases even-order distortions, and causes phase-to-intensity-noise conversion. Further distortions still, are caused by the Kerr nonlinearity of SSMF. We propose to address all of these shortcomings by replacing SSMFs with hollow-core optical fibres, which have simultaneously six times lower chromatic dispersion and several orders of magnitude lower nonlinearity (Brillouin, Kerr). We demonstrate the advantages in this application using a 7.7 km long hollow-core fibre sample, significantly surpassing the performance of an SSMF link in virtually every metric, including 15 dB higher link gain and 6 dB lower noise figure.

关键词： nonlinearity microwave shortcomings

Analyzing biases of nitrogen contents and δ^(15)N values arising from acidified marine sediments with different CaCO_3 concentrations

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Acta Oceanologica Sinica 2018年第8期37卷 1-5页

作者： PENG Yajun LIU Dongyan WANG Yujue richard Pierre KEESING john K. Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation Yantai Institute of Coastal Zone Research Chinese Academy of Sciences School of Management Science Guizhou University of Finance and Economics State Key Laboratory of Estuarine and Coastal Research East China Normal University Littoral Environment et Sociétés UMR 7266 CNRS-Université de La Rochelle CSIRO Oceans and Atmosphere and University of Western Australia Oceans Institute Indian Ocean Marine Research Centre

In some studies, the researchers pretreated and measured organic carbon, nitrogen and their isotopes（δ^（13）C and δ^（15）N） of marine sediment together, to save costs and resources of analysis. However, the procedure of acidification to remove inorganic carbon for analysing δ^（13）C can affect the values of nitrogen and δ^（15）N, and the biases vary a lot depending on the CaCO_3 contents of sediments. In this study, the biases of total nitrogen（TN）and δ^（15）N values arising from acidified sediments were compared between the CaCO_3-poor（1%–16%） and CaCO_3-rich（20%–40%） samples. TN and δ^（15）N values were altered during acid treatment（without centrifugation） that possibly led to N-containing compounds volatilization. For CaCO_3-poor samples, acidification led to a range of 0%–40% TN losses and 0‰–2‰ shift in δ^（15）N values; and 10%–60% TN losses and 1‰–14‰ shift in δ^（15）N values for CaCO_3-rich samples. The biases from most samples exceeded the precision of the instrument（0.002% for TN and 0.08‰ for δ^（15）N）, and high biases could mislead our judgment for the environmental implication of the data. Thus,avoiding co-analysis of organic carbon, nitrogen and their isotopes（δ^（13）C and δ^（15）N） in sediments, even for CaCO_3-poor marine sediments, is necessary.

关键词： stable isotope nitrogen nitrogen CaCO3 acidification marine sediment

Vegetation and Environment History for the Past 14 000 yr BP from Dingnan, Jiangxi Province, South China

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Journal of Integrative Plant Biology 2006年第9期48卷 1018-1027页

作者： john richard Dodson Shirene Hickson Rachel Khoo Xiao-Qiang Li Jemina Toia Wei-Jian Zhou Institute for the Environment Brunel University Uxbridge UB8 3PH England School of Earth and Geographical Sciences University of Western Australia Perth WA 6009 Australia State Key Laboratory of Loess and Quaternary Institute for Earth Environment the Chinese Academy of Sciences Xi＇an 710075 China

A Late Pleistocene-Holocene pollen, phosphorus, and charcoal record was reconstructed from a peatland in southern Jiangxi Province in southern China. The area today has a mountainous and rolling landscape with villages, small towns, and agriculture dominated by rice paddies, vegetable, and fruit gardens, as well as areas of secondary forest and pine re-afforestation. The record opens before 14 300 yr BP, with Alnus woodland dominating the wetland areas and with an open Quercus woodland on the surrounding slopes. The forest area becomes more complex from approximately 12 800 yr BP and further from 9 000 yr BP. At approximately 6 000 yr BP, there is evidence of clearing and, by 4 500-4 000 yr BP, a complete collapse in the wetland Alnus and terrestrial forest as the low-lying areas are converted to rice production. For much of the record, the occurrence of fire around the site was low, although there is evidence of regional fires. Fire was used as a tool in clearing and then used in the annual cycles of stubble burning after rice harvest. Nutrient levels, as reflected by total phosphorus in the sediment, seem to be closely related to forest changes and high values in the surface layers probably result from land-management techniques associated with agriculture. Therefore, human impact greatly altered forest cover, fire frequency, and nutrient dynamics; this has been evident for approximately 6 000 yr BP and then intensities towards the present day.

关键词： development of rice agriculture nutrient and fire history South China vegetation history

Is irritable bowel syndrome an infectious disease?

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World Journal of Gastroenterology 2016年第4期22卷 1331-1334页

作者： john richard Thompson Department of Pharmacy Practice Lipscomb University College of PharmacyOne University Park DriveNashvilleTN 37204United States

Irritable bowel syndrome(IBS) is the most common of all gastroenterological diseases. While many mechanisms have been postulated to explain its etiology, no single mechanism entirely explains the heterogeneity of symptoms seen with the various phenotypes of the disease. Recent data from both basic and clinical sciences suggest that underlying infectious disease may provide a unifying hypothesis that better explains the overall symptomatology. The presence of small intestinal bowel overgrowth(SIBO) has been documented in patients with IBS and reductions in SIBO as determined by breath testing correlate with IBS symptom improvement in clinical trials. The incidence of new onset IBS symptoms following acute infectious gastroenteritis also suggests an infectious cause. Alterations in microbiota-host interactions may compromise epithelial barrier integrity, immune function, and the development and function of both central and enteric nervous systems explaining alterations in the brain-gut axis. Clinical evidence from treatment trials with both probiotics and antibiotics also support this etiology. Probiotics appear to restore the imbalance in the microflora and improve IBS-specific quality of life. Antibiotic trials with both neomycin and rifaximin show improvement in global IBS symptoms that correlates with breath test normalization in diarrhea-predominant patients. The treatment response to two weeks of rifaximin is sustained for up to ten weeks and comparable results are seen in symptom reduction with retreatment in patients who develop recurrent symptoms.

关键词： irritable bowel syndrome pathopohysiology etiology Probiotics antibiotics infectious disease

How Prime Numbers Are Interconnected and Built with Two Equations: Addition and Subtraction Rules the Function (6µ)

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Advances in Pure Mathematics 2024年第4期14卷 228-241页

作者： john richard Wisdom Centre of Pedagogical Innovation (Capsule) Sorbonne University Paris France

Are all prime numbers linked by four simple functions? Can we predict when a prime will appear in a sequence of primes? If we classify primes into two groups, Group 1 for all primes that appear before ζ (such that , for instance 5, ), an even number divisible by 3 and 2, and Group 2 for all primes that are after ζ (such that , for instance 7), then we find a simple function: for each prime in each group, , where n is any natural number. If we start a sequence of primes with 5 for Group 1 and 7 for Group 2, we can attribute a μ value for each prime. The μ value can be attributed to every prime greater than 7. Thus for Group 1, and . Using this formula, all the primes appear for , where μ is any natural number.

关键词： Number Theory Prime Number Groups Twin Primes Prime Structure and Sequence Prime Subtraction and Addition

Optical read-out and modulation of peripheral nerve activity

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Neural Regeneration Research 2018年第1期13卷 58-61页

作者： Arjun K.Fontaine Hans E.Anderson john H.Caldwell richard F.Weir Department of Bioengineering University of Colorado – Anschutz Medical Campus Department of Cell and Developmental Biology University of Colorado – Anschutz Medical Campus

Numerous clinical and research applications necessitate the ability to interface with peripheral nerve fibers to read and control relevant neural pathways. Visceral organ modulation and rehabilitative prosthesis are two areas which could benefit greatly from improved neural interfacing approaches. Therapeutic neural interfacing, or ‘bioelectronic medicine’, has potential to affect a broad range of disorders given that all the major organs of the viscera are neurally innervated. However, a better understanding of the neural pathways that underlie function and a means to precisely interface with these fibers are required. Existing peripheral nerve interfaces, consisting primarily of electrode-based designs, are unsuited for highly specific （individual axon） communication and/or are invasive to the tissue. Our laboratory has explored an optogenetic approach by which optically sensitive reporters and actuators are targeted to specific cell （axon） types. The nature of such an approach is laid out in this short perspective, along with associated technologies and challenges.

关键词： peripheral nerve interface optogenetics bioelectronic medicine prosthesis control adeno-associated virus GCaMP

Impact of androgen deprivation therapy on sexua function： a response

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Asian Journal of Andrology 2012年第5期14卷 793-794页

作者： Erik Wibowo richard Wassersug Karen Warkentin Lauren Walker john Robinson Lori Brotto Thomas johnson Department of Anatomy&Neurobiology Dalhousie UniversityHalifaxNS B3H 4R2Canada Men's Health Initiative of B.C. Department of Urologic SciencesUniversity of British ColumbiaVancouverBC V5Z 1M9Canada Department of Biology Boston UniversityBostonMA 02215USA Department of Psychology University of CalgaryCalgaryAB T2N 1N4Canada Department of Psychosocial Resources Tom Baker Cancer CentreCalgaryAB T2S 3C1Canada UBC Sexual Health Lab Gordon&Leslie Diamond Health Care CentreDepartment of Obstetrics/GynecologyDivision of Gynecologic OncologyVancouverBC V5Z 1M9Canada Department of Anthropology California State UniversityFultonCA 95439-0050USA

Dear Editors, We appreciate the growing patients and survivors. Mazzola interest in sexual health for cancer and Mulhall＇s recent paper,a however, creates the impression that rewarding sex is not possible for prostate cancer patients on androgen deprivation therapy （ADT）. This impression, we believe, is not scientifically justified,

关键词： androgen therapy estosterone