By processing more than 400 000 planetary observations of various types with the dynamical models of the EPM2006 ephemerides, E.V. Pitjeva recently estimated a correction to the canonical Newtonian-Einsteinian Venus' perihelion precession of − 0.0004 ± 0.0001 arcseconds per century. The prediction of general relativity for the Lense-Thirring precession of the perihelion of Venus is − 0.0003 arcseconds per century. It turns out that neither other mismodelled/unmodelled standard Newtonian/Einsteinian effects nor exotic ones, postulated to, for example, explain the Pioneer anomaly, may have caused the estimated extra-precession of the Venus orbit which, thus, can be reasonably attributed to the gravitomagnetic field of the Sun, not modelled in the routines of the EPM2006 ephemerides. However, it must be noted that the quoted error is the formal, statistical one; the realistic uncertainty might be larger. Future improvements of the inner planets' ephemerides, with the inclusion of the Messenger and Venus-Express tracking data, should further improve the accuracy and the consistency of such a test of general relativity which would also benefit from the independent estimation of the extra-precessions of the perihelia (and the nodes) by other teams of astronomers.
{"title":"Advances in the Measurement of the Lense-Thirring Effect with Planetary Motions in the Field of the Sun","authors":"L. Iorio","doi":"10.3814/2008/105235","DOIUrl":"https://doi.org/10.3814/2008/105235","url":null,"abstract":"By processing more than 400 000 planetary observations of various types \u0000with the dynamical models of the EPM2006 ephemerides, E.V. Pitjeva recently \u0000estimated a correction to the canonical Newtonian-Einsteinian Venus' perihelion \u0000precession of − 0.0004 ± 0.0001 arcseconds per century. The prediction of general \u0000relativity for the Lense-Thirring precession of the perihelion of Venus is − 0.0003 arcseconds per century. It turns out that neither other mismodelled/unmodelled \u0000standard Newtonian/Einsteinian effects nor exotic ones, postulated to, for example, \u0000explain the Pioneer anomaly, may have caused the estimated extra-precession \u0000of the Venus orbit which, thus, can be reasonably attributed to the \u0000gravitomagnetic field of the Sun, not modelled in the routines of the EPM2006 \u0000ephemerides. However, it must be noted that the quoted error is the formal, \u0000statistical one; the realistic uncertainty might be larger. Future improvements of \u0000the inner planets' ephemerides, with the inclusion of the Messenger and Venus-Express tracking data, should further improve the accuracy and the consistency \u0000of such a test of general relativity which would also benefit from the independent \u0000estimation of the extra-precessions of the perihelia (and the nodes) by other teams \u0000of astronomers.","PeriodicalId":169134,"journal":{"name":"Scholarly Research Exchange","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128371436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The limit cycle of the van der Pol oscillator, x ¨ + e ( x 2 − 1 ) x ˙ + x = 0 , is studied in the plane ( x , x ˙ ) by applying the homotopy analysis method. A recursive set of formulas that approximate the amplitude and form of this limit cycle for the whole range of the parameter e is obtained. These formulas generate the amplitude with an error less than 0.1%. To our knowledge, this is the first time where an analytical approximation of the amplitude of the van der Pol limit cycle, with validity from the weakly up to the strongly nonlinear regime, is given.
利用同伦分析方法研究了van der Pol振子x′+ e (x2−1)x˙+ x = 0在平面(x, x˙)上的极限环。得到了在参数e的整个范围内近似极限环的幅值和形式的一组递推公式。这些公式产生的振幅误差小于0.1%。据我们所知，这是第一次给出van der Pol极限环的振幅的解析近似，具有从弱到强非线性的有效性。
{"title":"Formulas for the Amplitude of the van der Pol Limit Cycle through the Homotopy Analysis Method","authors":"J. López, S. Abbasbandy, R. López-Ruiz","doi":"10.3814/2009/854060","DOIUrl":"https://doi.org/10.3814/2009/854060","url":null,"abstract":"The limit cycle of the van der Pol oscillator, x ¨ + e ( x 2 − 1 ) x ˙ + x = 0 , is studied in the plane ( x , x ˙ ) by applying the homotopy analysis method. A recursive set of \u0000formulas that approximate the amplitude and form of this limit cycle for the whole range of the parameter e is obtained. These formulas generate the amplitude with an error less than 0.1%. To our knowledge, this is the first time where an analytical approximation of the amplitude of the van der Pol limit cycle, with validity from \u0000the weakly up to the strongly nonlinear regime, is given.","PeriodicalId":169134,"journal":{"name":"Scholarly Research Exchange","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127236287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ion-specific effects underlie a vast array of physicochemical and biological phenomena ranging from human physiology to biotechnology to ecology. These effects have traditionally been quantified by measuring the response of interest in a series of salt solutions at multiple concentrations; pH has consistently been shown to be of primary concern. However, salt-based approaches violate critical tenets of proper experimental design and introduce confounding errors that make it impossible to quantify ion-specific effects. For example, pH is a variable dependent on the type and concentration of ions in a solution, but is typically treated as an independent factor, thus confounding experiments designed to determine ion-specific effects. We examined the relevancy of ion-specific effects research in relation to these concepts and demonstrated how these ideas impact protein precipitation and enzyme activity. Based on these results, we present a conceptual and experimental framework of general applicability for proper quantification of ion-specific effects.
{"title":"Are Hofmeister Series Relevant to Modern Ion-Specific Effects Research?","authors":"T. Evens, R. Niedz","doi":"10.3814/2008/818461","DOIUrl":"https://doi.org/10.3814/2008/818461","url":null,"abstract":"Ion-specific effects underlie a vast array of physicochemical and biological phenomena ranging from human physiology to biotechnology to ecology. These effects have traditionally been quantified by measuring the response of interest in a series of salt solutions at multiple concentrations; pH has consistently been shown to be of primary concern. However, salt-based approaches violate critical tenets of proper experimental design and introduce confounding errors that make it impossible to quantify ion-specific effects. For example, pH is a variable dependent on the type and concentration of ions in a solution, but is typically treated as an independent factor, thus confounding experiments designed to determine ion-specific effects. We examined the relevancy of ion-specific effects research in relation to these concepts and demonstrated how these ideas impact protein precipitation and enzyme activity. Based on these results, we present a conceptual and experimental framework of general applicability for proper quantification of ion-specific effects.","PeriodicalId":169134,"journal":{"name":"Scholarly Research Exchange","volume":"2008 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129119301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhixun Xie, Jianbao Dong, Xiaofei Tang, Liu Jiabo, Mazhar I. Khan, Y. Pang, Xianwen Deng, Zhiqin Xie
Three isolates of H9N2 subtype of influenza virus have been isolated from chickens in Guangxi province. In this study, eight full-length genes of each of the H9N2 isolates, A/Chicken/Guangxi/1/00, A/Chicken/Guangxi/14/00, and A/Chicken/Guangxi/17/00, were obtained. Sequence analysis and phylogenetic studies were conducted by comparing eight genes of each isolate with those of the available H9N2 strains at GenBank. Results showed a high degree of homology between the Guangxi isolates and isolates from Guangdong and Jiangsu provinces, suggesting that Guangxi isolates originated from the same source. However, the eight genes of these three isolates from Guangxi were not in the same sublineages in the phylogenic trees, which suggest that they were products of natural reassortment between H9N2 avian influenza viruses from different sublineages. The 9 nucleotides ACAGAGATA encoding amino acids T, E, I were absent between nucleotide 205 and 214 in the open reading frame of NA genes in the Guangxi isolates. AIV strains that infect human have in their HA proteins, Leucine at position 226. The analysis of deduced amino acid sequence of HA proteins of C/GX/1/00, C/GX/14/00, and C/GX/17/00 showed that the position 226 of these isolates was glycine instead of leucine, suggesting that these three isolates differ from H9N2 AIV strains isolated from human infections.
{"title":"Sequence and Phylogenetic Analysis of Three Isolates of Avian Influenza H9N2 from Chickens in Southern China","authors":"Zhixun Xie, Jianbao Dong, Xiaofei Tang, Liu Jiabo, Mazhar I. Khan, Y. Pang, Xianwen Deng, Zhiqin Xie","doi":"10.3814/2008/802317","DOIUrl":"https://doi.org/10.3814/2008/802317","url":null,"abstract":"Three isolates of H9N2 subtype of influenza virus have been isolated from chickens in Guangxi province. In this study, eight full-length genes of each of the H9N2 isolates, A/Chicken/Guangxi/1/00, A/Chicken/Guangxi/14/00, and A/Chicken/Guangxi/17/00, were obtained. Sequence analysis and phylogenetic studies were conducted by comparing eight genes of each isolate with those of the available H9N2 strains at GenBank. Results showed a high degree of homology between the Guangxi isolates and isolates from Guangdong and Jiangsu provinces, suggesting that Guangxi isolates originated from the same source. However, the eight genes of these three isolates from Guangxi were not in the same sublineages in the phylogenic trees, which suggest that they were products of natural reassortment between H9N2 avian influenza viruses from different sublineages. The 9 nucleotides ACAGAGATA encoding amino acids T, E, I were absent between nucleotide 205 and 214 in the open reading frame of NA genes in the Guangxi isolates. AIV strains that infect human have in their HA proteins, Leucine at position 226. The analysis of deduced amino acid sequence of HA proteins of C/GX/1/00, C/GX/14/00, and C/GX/17/00 showed that the position 226 of these isolates was glycine instead of leucine, suggesting that these three isolates differ from H9N2 AIV strains isolated from human infections.","PeriodicalId":169134,"journal":{"name":"Scholarly Research Exchange","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129494606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We consider the recently estimated corrections Δω¯˙ to the standard Newtonian/Einsteinian secular precessions of the longitudes of perihelia ω¯ of several planets of the Solar System in order to evaluate whether they are compatible with the predicted anomalous precessions due to models of long-range modified gravity put forth to account for certain features of the rotation curves of galaxies without resorting to dark matter. In particular, we consider a logarithmic-type correction and a f(R) inspired power-law modification of the Newtonian gravitational potential. The results obtained by taking the ratio of the predicted apsidal rates for different pairs of planets show that the modifications of the Newtonian potentials examined in this paper are not compatible with the secular extra-precessions of the perihelia of the Solar System's planets estimated by E. V. Pitjeva as solve-for parameters processing almost one century of data with the latest EPM ephemerides.
{"title":"Solar System Tests of Some Models of Modified Gravity Proposed to Explain Galactic Rotation Curves without Dark Matter","authors":"L. Iorio, M. Ruggiero","doi":"10.3814/2008/968393","DOIUrl":"https://doi.org/10.3814/2008/968393","url":null,"abstract":"We consider the recently estimated corrections Δω¯˙ to the standard Newtonian/Einsteinian secular precessions of the longitudes of perihelia ω¯ of several planets of the Solar System in order to evaluate whether they are compatible with \u0000the predicted anomalous precessions due to models of long-range modified gravity put forth to account for certain features of the rotation curves of galaxies without resorting to dark matter. In particular, we consider a logarithmic-type correction and a \u0000f(R) inspired power-law modification of the Newtonian gravitational potential. The results obtained by taking the ratio of the predicted apsidal rates for different pairs of planets show that the modifications of the Newtonian potentials examined in \u0000this paper are not compatible with the secular extra-precessions of the perihelia \u0000of the Solar System's planets estimated by E. V. Pitjeva as solve-for parameters \u0000processing almost one century of data with the latest EPM ephemerides.","PeriodicalId":169134,"journal":{"name":"Scholarly Research Exchange","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128213581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A 70-year-old woman with recurred episodes of angina pectoris was admitted to our hospital for evaluation. After coronary angiography, a coronary-subclavian steal syndrome was reveled. A PICA in subclavian artery was performed to treat this patient.
{"title":"Coronary-Subclavian Steal Syndrome: A Rare Cause of Angina Pectoris","authors":"D. Papadopoulos, V. Votteas","doi":"10.3814/2008/541085","DOIUrl":"https://doi.org/10.3814/2008/541085","url":null,"abstract":"A 70-year-old woman with recurred episodes of angina pectoris was \u0000admitted to our hospital for evaluation. After coronary \u0000angiography, a coronary-subclavian steal syndrome was reveled. A \u0000PICA in subclavian artery was performed to treat this patient.","PeriodicalId":169134,"journal":{"name":"Scholarly Research Exchange","volume":"125 48","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113939983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Objectives. This work is a trial to elucidate the parasitological and histopathological sequelae of giving the antimalarial drug (artesunate) in experimental intestinal amoebiasis. Methods. A group of 24 hamsters was infected by Entamoeba histolytica cysts orally using a canula. This group was subdivided into two main subgroups. Subgroup I: given 6000 E. histolytica cysts orally by a canula, then sacrificed five weeks postinfection. Subgroup II : given the same infective dose, then two weeks later, treated with artesunate 10 mgm/Kg b. wt/hamster over 3 consecutive days. Again sacrifice was performed five weeks postinfection. Multiple stool examinations, and histopathological examination of the caecal end of the large intestine were resorted to, in order to assess the antiamoebic effect of the drug. Faecal smear examination revealed absolute disappearance of E. histolytica cysts in the treated group. Again, histopathology of the mucosal scrapings of the caecum showed complete absence of Entamoeba histolytica trophozoites in the treated group, when compared to the control animals (P<.001). This study may be beneficial, especially in areas endemic with amoebiasis to help overcoming the emerging resistance to the usually available antiamoebic drugs.
目标。本研究旨在阐明在实验性肠阿米巴病中给予抗疟药物(青蒿琥酯)的寄生虫学和组织病理学后遗症。方法。24只仓鼠经灌口感染溶组织内阿米巴囊肿。这一组被细分为两个主要的亚组。第一小组:给定6000 E。通过导管口服溶组织囊肿，然后在感染后5周处死。第二组:给予相同的感染剂量，两周后给予青蒿琥酯10 mg /Kg b. wt/仓鼠，连续3天。感染后5周再次献祭。多次大便检查和大肠盲肠末端的组织病理学检查，以评估药物的抗阿米巴作用。粪便涂片检查显示治疗组溶组织芽胞杆菌囊肿完全消失。同样，与对照组动物相比，盲肠粘膜刮擦的组织病理学显示，治疗组完全没有溶组织内阿米巴滋养体(P< 0.001)。这项研究可能是有益的，特别是在阿米巴病流行地区，以帮助克服对通常可用的抗阿米巴药物的新耐药性。
{"title":"Morbid Parasitological and Histopathological Events in Hamsters Infected with Intestinal Amoebiasis Given Artesunate","authors":"S. Mahmoud, N. Nessim","doi":"10.3814/2008/327318","DOIUrl":"https://doi.org/10.3814/2008/327318","url":null,"abstract":"Objectives. This work is a trial to elucidate the parasitological and histopathological sequelae of giving the antimalarial drug (artesunate) in experimental intestinal amoebiasis. Methods. A group of 24 hamsters was infected by Entamoeba histolytica cysts orally using a canula. This group was subdivided into two main subgroups. Subgroup I: given 6000 E. histolytica cysts orally by a canula, then sacrificed five weeks postinfection. Subgroup II : given the same infective dose, then two weeks later, treated with artesunate 10 mgm/Kg b. wt/hamster over 3 consecutive days. Again sacrifice was performed five weeks postinfection. Multiple stool examinations, and histopathological examination of the caecal end of the large intestine were resorted to, in order to assess the antiamoebic effect of the drug. Faecal smear examination revealed absolute disappearance of E. histolytica cysts in the treated group. Again, histopathology of the mucosal scrapings of the caecum showed complete absence of Entamoeba histolytica trophozoites in the treated group, when compared to the control animals (P<.001). This study may be beneficial, especially in areas endemic with amoebiasis to help overcoming the emerging resistance to the usually available antiamoebic drugs.","PeriodicalId":169134,"journal":{"name":"Scholarly Research Exchange","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132523877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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