Language is an important carrier of human culture and a specific method for communication between humans.It is one of the most important symbols of human identity and flags of dividing group identity.At present,in the...Language is an important carrier of human culture and a specific method for communication between humans.It is one of the most important symbols of human identity and flags of dividing group identity.At present,in the modern national state,the government is paying more attention to language policy and being more and more prudent to it.In the process of making and implementing language policy,the government must take into account a range of factors such as the country’s national history,politics,culture,economy,and relations between different social groups.From the mid-nineteenth century,when New Zealand became a British colony,until the mid-twentieth century,the Maori people were inspired to defend their rights and respect for themselves by the rise of Maori nationalist ideology and Maori political radicalism in a struggle that lasted more than 100 years.Until 1994,there were more than 800 kohanga reo,early childhood institutions that established Maori language instruction independent of the school system,and the nationalism drives to revitalize the Maori national language was at its peak.The process of revolution on Maori language policies in New Zealand reflects a trend of nationalist thoughts from Maori becoming more deep.Exploring the process of change in New Zealand’s Maori language policy will help to develop the study of the social history of indigenous peoples during the colonial period and will contribute to the study of the development of colonized countries and regions in the post-colonial period.The change in New Zealand’s Maori language policy has provided an important example of the preservation and revitalization of the indigenous languages of the world’s former colonies,which is of great significance for the preservation of linguistic and cultural diversity.展开更多
BACKGROUND Prevotella oris-induced meningitis and Prevotella oris-induced meningitis concomitant with spinal canal infection are extremely rare.To the best of our knowledge,only 1 case of Prevotella oris-induced centr...BACKGROUND Prevotella oris-induced meningitis and Prevotella oris-induced meningitis concomitant with spinal canal infection are extremely rare.To the best of our knowledge,only 1 case of Prevotella oris-induced central system infection has been reported.This is the second report on meningitis combined with spinal canal infection due to Prevotella oris.CASE SUMMARY We report a case of a 9-year-old boy suffering from meningitis and spinal canal infection.The patient presented to the neurosurgery department with lumbosacral pain for 1 mo and headache and vomiting for 1 d.He had been treated with cephalosporin and nonsteroidal anti-inflammatory drugs for fever,otalgia and pharyngalgia in a local hospital 2 mo prior to this admission.During hospitalization,magnetic resonance imaging suggested meningitis and L3-S1 lumbosacral dural sac infection.The cerebrospinal fluid and blood cultures were negative,but the cerebrospinal fluid specimen indicated the presence of Prevotella oris by metagenomic next-generation sequencing.Previous cases of Prevotella oris infection were retrieved from PubMed to characterize the clinicopathological features and identify the prognostic factors and related antimicrobial treatment of infection due to Prevotella oris.CONCLUSION This report shed light on the characteristics of Prevotella oris infection and highlighted the role of metagenomic next-generation sequencing in pathogen detection.展开更多
AIM:To compare the costs and effectiveness of no screening and no eradication therapy, the population- based Helicobacter pylori (H pylori) serology screening with eradication therapy and 13C-Urea breath test (UBT) wi...AIM:To compare the costs and effectiveness of no screening and no eradication therapy, the population- based Helicobacter pylori (H pylori) serology screening with eradication therapy and 13C-Urea breath test (UBT) with eradication therapy. METHODS:A Markov model simulation was carried out in all 237 900 Chinese males with age between 35 and 44 from the perspective of the public healthcare provider in Singapore. The main outcome measures were the costs, number of gastric cancer cases prevented, life years saved, and quality-adjusted life years (QALYs) gained from screening age to death. The uncertainty surrounding the cost-effectiveness ratio was addressed by one-way sensitivity analyses. RESULTS:Compared to no screening, the incremental cost-effectiveness ratio (ICER) was $16 166 per life year saved or $13 571 per QALY gained for the serology screening, and $38 792 per life year saved and $32 525 per QALY gained for the UBT. The ICER was $477 079 per life year saved or $390 337 per QALY gained for the UBT compared to the serology screening. The cost- effectiveness of serology screening over the UBT was robust to most parameters in the model. CONCLUSION:The population-based serologyscreening for H pylori was more cost-effective than the UBT in prevention of gastric cancer in Singapore Chinese males.展开更多
AIM： To investigate the efficacy and tolerability of H pylori eradication in an omeprazole-based triple therapy with high and low dose of clarithromycin and amoxicillin. METHODS： One hundred and sixty H pylori posi...AIM： To investigate the efficacy and tolerability of H pylori eradication in an omeprazole-based triple therapy with high and low dose of clarithromycin and amoxicillin. METHODS： One hundred and sixty H pylori positive patients were randomly assigned to two groups based on the following 2 wk investigation; （1） group A or low-dose regimen received omeprazole 20 mg b.i.d, clarithromycin 250 mg b.i.d and amoxicillin 500 mg b.i.d; and （2） group B or high-dose regimen received omeprazole 20 mg b.i.d, clarithromycin 500 mg b.i.d and amoxicillin 1000 mg b.i.d. During the study Hpylori status was assessed by histology and rapid urease test prior and by 13C-urea breath test 6 wk after the therapy. Standard questionnaires were administered to determine the compliance to treatment and possible adverse events of therapy. Data were subject to x^2 to compare the eradication rates in the two groups. The significant level of 95% （P ≤ 0.05） was considered statistically different. RESULTS： We found that the per-protocol eradication rate was 88% （68/77） in group A, and 89% （67/75） in group B. The intension-to-treat eradication rate was 85% （68/80） in group A and 83.75% （67180） in group B. Overall adverse events were 26% in group A and 31% in group B. The adverse events were generally mild in nature and tolerated well in both groups with a compliance of 98% in group A vs 96% in group B. CONCLUSION： The omeprazole-based low dose regimen of darithromycin and amoxicillin for two weeks in Hpylori eradication is as effective as high dose regimen in Iranian population.展开更多
AIM： To assess long-term effects of Helicobacter pylori （H pylon} eradication on antral G cell morphology and function in patients with and without duodenal ulcer （DU）.METHODS： Consecutive dyspeptic patients refe...AIM： To assess long-term effects of Helicobacter pylori （H pylon} eradication on antral G cell morphology and function in patients with and without duodenal ulcer （DU）.METHODS： Consecutive dyspeptic patients referred to the endoscopy entered the study. Out of 39 Hpylori positive patients, 8 had DU （Hpylori ＋DU） and 31 gastritis （Hpylori＋G）. Control groups consisted of 11 uninfected dyspeptic patients （CG1） and 7 healthy volunteers （CG2）. Basal plasma gastrin （PGL）, antral tissue gastrin concentrations （ATGC）, immunohistochemical and electron microscopic characteristics of G cells were determined, prior to and 6 mo after therapy.RESULTS： We-demonstrated elevated PGL in infected patients compared to uninfected controls prior to therapy.Elevated PGL were registered in all Hpylori＋patients （Hpylori＋DU： 106.78＋22.72 pg/mL, Hpylori＋G： 74.95＋15.63,CGI： 68.59＋17.97, CG2：39.24＋5.59 pg/mL, P〈0.01）.Successful eradication （e） therapy in Hpylori＋patients lead to significant decrease in PGL （Hpylori＋DU： 59.93＋9.40 and Hpylori＋Ge： 42.36＋10.28 pg/mL, P〈0.001）. ATGC at the beginning of the study were similar in infected and uninfected patients and eradication therapy lead to significant decrease in ATGC in Hpylori＋gastritis, but not in DU patients. In the Hpylori＋DU patients, the mean number of antral G cells was significantly lower in comparison with all other groups （P〈0.01）, but after successful eradication was close to normal values found in controls. By contrast, G cell number and volume density were significantly decreased （P〈0.01） in Hpylori＋Ge group after successful eradication therapy （294＋32 and 0.31＋0.02,respectively）, in comparison to values before eradication （416~40 and 0.48~0.09）. No significant change of the G cell/total endocrine cell ratio was observed during the 6 mo of follow up in any of the groups. A reversible increase in G cell secretory function was seen in all infected individuals, demonstrated by a more prominent secretory apparatus. However, differences between DU and gastritis group were identified.CONCLUSION： H py/oriinfection induces antral G cell hyperfunction resulting in increased gastrin synthesis and secretion. After eradication therapy complete morphological and functional recovery is observed in patients with gastritis. In the DU patients some other factors unrelated to the Hpyloriinfection influence antral G cell morphology and function.展开更多
A photometric analysis and evolutionary stages of the contact binary V2790 Ori are presented.The BV RC observations were carried out at the Thai National Observatory. The photometric light curves were fitted to provid...A photometric analysis and evolutionary stages of the contact binary V2790 Ori are presented.The BV RC observations were carried out at the Thai National Observatory. The photometric light curves were fitted to provide fundamental parameters, required to examine evolutionary stages of the binary. The results indicate that V2790 Ori is a W-type contact system with a mass ratio of q = 2.932. The orbital period increase is found at a rate of d P/dt = 1.03×10^-7 d yr^-1. This implies that a rate of mass transfer from the secondary component to the primary one is dm2/dt =6.31×10^-8 M⊙yr^-1. Furthermore, we find that from the detached phase to the contact phase, the amount of mass that the evolved secondary component has lost is 1.188±0.110 M⊙, i.e., mass lost by the system is 0.789±0.073 M⊙and mass transfer to the primary is0.399±0.037 M⊙. Since the time of the first overflow, the angular momentum loss is found to be 72.2% of JFOF, causing the orbit and Roche surface to shrink until the present time.展开更多
Four-color charge-coupled device(CCD) light curves in the B, V, Rc and I c bands of the totaleclipsing binary system V1853 Orionis(V1853 Ori) are presented. By comparing our light curves with those published by previo...Four-color charge-coupled device(CCD) light curves in the B, V, Rc and I c bands of the totaleclipsing binary system V1853 Orionis(V1853 Ori) are presented. By comparing our light curves with those published by previous investigators, it is determined that the O'Connell effect on the light curves has disappeared. By analyzing those multi-color light curves with the Wilson-Devinney code(W-D code),it is discovered that V1853 Ori is an A-type intermediate-contact binary with a degree of contact factor of f = 33.3%(3.7%) and a mass ratio of q = 0.1896(0.0013). Combining our 10 newly determined times of light minima together with others published in the literature, the period changes of the system are investigated. We found that the general trend of the observed minus calculated(O-C) curve shows a downward parabolic variation that corresponds to a long-term decrease in the orbital period with a rate of d P/dt =-1.96(0.46)×10^(-7) d yr^(-1). The long-term period decrease could be explained by mass transfer from the more-massive component to the less-massive one. By combining our photometric solutions with data from Gaia DR_2, absolute parameters were derived as M_1 = 1.20 M⊙, M_2 = 0.23 M⊙, R_1 = 1.36 R⊙and R_2 = 0.66 R⊙. The long-term period decrease and intermediate-contact configuration suggest that V1853 Ori will evolve into a high fill-out overcontact binary.展开更多
We present new photometry for two contact binaries,Y Sex and V1363 Ori,which were observed by three small telescopes in China.By using the W-D method,the absolute parameters are updated from new BVR light curves and p...We present new photometry for two contact binaries,Y Sex and V1363 Ori,which were observed by three small telescopes in China.By using the W-D method,the absolute parameters are updated from new BVR light curves and previous radial velocity curves.Results identify that two binaries are deep,lowmass ratio(DLMR)overcontact binaries with q≤0.25 and f≥50%.From the temperature-luminosity diagram,the primary components are slightly evolved main-sequence stars,whose evolutionary ages are~2.51 Gyr for Y Sex and~3.56 Gyr for V 1363 Ori,respectively.From the(O-C)curves,it is found that the orbital periods may be undergoing secular increase with cyclic variations,which may be interpreted either by magnetic activity cycles or by the light-time orbit effect.With period increasing,this kind of DLMR overcontact binaries,such as Y Sex and V1363 Ori,will evolve into the rapid-rotating single stars.展开更多
The first photometric solution in the B,V,R_(c) and I_(c) filters of the short period V1833 Ori eclipsing binary is presented based on new ground-based CCD photometric observations.We analyzed the BVRI photometric lig...The first photometric solution in the B,V,R_(c) and I_(c) filters of the short period V1833 Ori eclipsing binary is presented based on new ground-based CCD photometric observations.We analyzed the BVRI photometric light curves of the system,using PHOEBE 0.31 a,a binary star modeling program,with the Wilson-Devinney method based on Roche geometry to achieve the best accordance with the photometric observations to determine their absolute parameters from the light curves.We updated the ephemeris of V1833 Ori using two new light curve minima derived by our new observational data from those collected in the literature and analyzed the change of the system's orbital period.The O-C analysis indicates that the variations of the orbital period of V1833 Ori with time are increasing at a rate of 3.03×10^(-7)days yr^(-1).The distance of V1833 Ori is 173.7±15.6 pc.From the solutions,we find that V1833 Ori is an A-subtype W UMa overcontact binary with q=0.701 mass ratio and f=1.14 fill-out factor.The HR diagram positions of the eclipsing binary system's components are discussed.The system's absolute dimensions were compared to those of similar binaries in the log T_(eff)-log L,logM-logL,1 ogM-logR and logM-log J_(0)diagrams.展开更多
We obtained new high-resolution spectra using the Lijiang 1.8-m and 2.4-m telescopes to inves- tigate the chromospheric activities of V1355 Ori as indicated in the behaviors of Ca n H＆K, Hγ HT, H/3, Na1 D1, D2, Ha a...We obtained new high-resolution spectra using the Lijiang 1.8-m and 2.4-m telescopes to inves- tigate the chromospheric activities of V1355 Ori as indicated in the behaviors of Ca n H＆K, Hγ HT, H/3, Na1 D1, D2, Ha and Ca II infrared triplet （IRT） lines. The observed spectra show obvious emissions above the continuum in Ca II H＆K lines, absorptions in the Hδ, Hγ, H/3 and NaI D1, D2 lines, variable behavior （filled-in absorption, partial emission with a core absorption component or emission above the continuum） in the Ha line, and weak self-reversal emissions in the strong filled-in absorptions of the Ca II IRT lines. We used a spectral subtraction technique to analyze our data. The results show no excess emission in the H6 and H7 lines, very weak excess emissions in the Na I D1, D2 lines, excess emission in the H/3 line, clear excess emission in the Ha line, and excess emissions in the Ca II IRT lines. The value of the ratio of EWs542/EWsa9s is in the range 0.9 to 1.7, which implies that chromospheric activity might have been caused by plage events. The value of the ratio EHδ/EHβ is above 3, indicating that the Balmer lines would arise from prominence-like material. We also found time variations in light curves associated with equiva- lent widths of chromospheric activity lines in the Na I D1, phenomena can be explained by plage events, which are activity indicators. D2, Ca II IRT and Ha lines in particular. These consistent with the behavior of chromospheric展开更多
文摘Language is an important carrier of human culture and a specific method for communication between humans.It is one of the most important symbols of human identity and flags of dividing group identity.At present,in the modern national state,the government is paying more attention to language policy and being more and more prudent to it.In the process of making and implementing language policy,the government must take into account a range of factors such as the country’s national history,politics,culture,economy,and relations between different social groups.From the mid-nineteenth century,when New Zealand became a British colony,until the mid-twentieth century,the Maori people were inspired to defend their rights and respect for themselves by the rise of Maori nationalist ideology and Maori political radicalism in a struggle that lasted more than 100 years.Until 1994,there were more than 800 kohanga reo,early childhood institutions that established Maori language instruction independent of the school system,and the nationalism drives to revitalize the Maori national language was at its peak.The process of revolution on Maori language policies in New Zealand reflects a trend of nationalist thoughts from Maori becoming more deep.Exploring the process of change in New Zealand’s Maori language policy will help to develop the study of the social history of indigenous peoples during the colonial period and will contribute to the study of the development of colonized countries and regions in the post-colonial period.The change in New Zealand’s Maori language policy has provided an important example of the preservation and revitalization of the indigenous languages of the world’s former colonies,which is of great significance for the preservation of linguistic and cultural diversity.
文摘BACKGROUND Prevotella oris-induced meningitis and Prevotella oris-induced meningitis concomitant with spinal canal infection are extremely rare.To the best of our knowledge,only 1 case of Prevotella oris-induced central system infection has been reported.This is the second report on meningitis combined with spinal canal infection due to Prevotella oris.CASE SUMMARY We report a case of a 9-year-old boy suffering from meningitis and spinal canal infection.The patient presented to the neurosurgery department with lumbosacral pain for 1 mo and headache and vomiting for 1 d.He had been treated with cephalosporin and nonsteroidal anti-inflammatory drugs for fever,otalgia and pharyngalgia in a local hospital 2 mo prior to this admission.During hospitalization,magnetic resonance imaging suggested meningitis and L3-S1 lumbosacral dural sac infection.The cerebrospinal fluid and blood cultures were negative,but the cerebrospinal fluid specimen indicated the presence of Prevotella oris by metagenomic next-generation sequencing.Previous cases of Prevotella oris infection were retrieved from PubMed to characterize the clinicopathological features and identify the prognostic factors and related antimicrobial treatment of infection due to Prevotella oris.CONCLUSION This report shed light on the characteristics of Prevotella oris infection and highlighted the role of metagenomic next-generation sequencing in pathogen detection.
文摘AIM:To compare the costs and effectiveness of no screening and no eradication therapy, the population- based Helicobacter pylori (H pylori) serology screening with eradication therapy and 13C-Urea breath test (UBT) with eradication therapy. METHODS:A Markov model simulation was carried out in all 237 900 Chinese males with age between 35 and 44 from the perspective of the public healthcare provider in Singapore. The main outcome measures were the costs, number of gastric cancer cases prevented, life years saved, and quality-adjusted life years (QALYs) gained from screening age to death. The uncertainty surrounding the cost-effectiveness ratio was addressed by one-way sensitivity analyses. RESULTS:Compared to no screening, the incremental cost-effectiveness ratio (ICER) was $16 166 per life year saved or $13 571 per QALY gained for the serology screening, and $38 792 per life year saved and $32 525 per QALY gained for the UBT. The ICER was $477 079 per life year saved or $390 337 per QALY gained for the UBT compared to the serology screening. The cost- effectiveness of serology screening over the UBT was robust to most parameters in the model. CONCLUSION:The population-based serologyscreening for H pylori was more cost-effective than the UBT in prevention of gastric cancer in Singapore Chinese males.
文摘AIM： To investigate the efficacy and tolerability of H pylori eradication in an omeprazole-based triple therapy with high and low dose of clarithromycin and amoxicillin. METHODS： One hundred and sixty H pylori positive patients were randomly assigned to two groups based on the following 2 wk investigation; （1） group A or low-dose regimen received omeprazole 20 mg b.i.d, clarithromycin 250 mg b.i.d and amoxicillin 500 mg b.i.d; and （2） group B or high-dose regimen received omeprazole 20 mg b.i.d, clarithromycin 500 mg b.i.d and amoxicillin 1000 mg b.i.d. During the study Hpylori status was assessed by histology and rapid urease test prior and by 13C-urea breath test 6 wk after the therapy. Standard questionnaires were administered to determine the compliance to treatment and possible adverse events of therapy. Data were subject to x^2 to compare the eradication rates in the two groups. The significant level of 95% （P ≤ 0.05） was considered statistically different. RESULTS： We found that the per-protocol eradication rate was 88% （68/77） in group A, and 89% （67/75） in group B. The intension-to-treat eradication rate was 85% （68/80） in group A and 83.75% （67180） in group B. Overall adverse events were 26% in group A and 31% in group B. The adverse events were generally mild in nature and tolerated well in both groups with a compliance of 98% in group A vs 96% in group B. CONCLUSION： The omeprazole-based low dose regimen of darithromycin and amoxicillin for two weeks in Hpylori eradication is as effective as high dose regimen in Iranian population.
基金Supported by a Grant From Serbian Ministry for Science, Technology and Development, No. 1752
文摘AIM： To assess long-term effects of Helicobacter pylori （H pylon} eradication on antral G cell morphology and function in patients with and without duodenal ulcer （DU）.METHODS： Consecutive dyspeptic patients referred to the endoscopy entered the study. Out of 39 Hpylori positive patients, 8 had DU （Hpylori ＋DU） and 31 gastritis （Hpylori＋G）. Control groups consisted of 11 uninfected dyspeptic patients （CG1） and 7 healthy volunteers （CG2）. Basal plasma gastrin （PGL）, antral tissue gastrin concentrations （ATGC）, immunohistochemical and electron microscopic characteristics of G cells were determined, prior to and 6 mo after therapy.RESULTS： We-demonstrated elevated PGL in infected patients compared to uninfected controls prior to therapy.Elevated PGL were registered in all Hpylori＋patients （Hpylori＋DU： 106.78＋22.72 pg/mL, Hpylori＋G： 74.95＋15.63,CGI： 68.59＋17.97, CG2：39.24＋5.59 pg/mL, P〈0.01）.Successful eradication （e） therapy in Hpylori＋patients lead to significant decrease in PGL （Hpylori＋DU： 59.93＋9.40 and Hpylori＋Ge： 42.36＋10.28 pg/mL, P〈0.001）. ATGC at the beginning of the study were similar in infected and uninfected patients and eradication therapy lead to significant decrease in ATGC in Hpylori＋gastritis, but not in DU patients. In the Hpylori＋DU patients, the mean number of antral G cells was significantly lower in comparison with all other groups （P〈0.01）, but after successful eradication was close to normal values found in controls. By contrast, G cell number and volume density were significantly decreased （P〈0.01） in Hpylori＋Ge group after successful eradication therapy （294＋32 and 0.31＋0.02,respectively）, in comparison to values before eradication （416~40 and 0.48~0.09）. No significant change of the G cell/total endocrine cell ratio was observed during the 6 mo of follow up in any of the groups. A reversible increase in G cell secretory function was seen in all infected individuals, demonstrated by a more prominent secretory apparatus. However, differences between DU and gastritis group were identified.CONCLUSION： H py/oriinfection induces antral G cell hyperfunction resulting in increased gastrin synthesis and secretion. After eradication therapy complete morphological and functional recovery is observed in patients with gastritis. In the DU patients some other factors unrelated to the Hpyloriinfection influence antral G cell morphology and function.
文摘A photometric analysis and evolutionary stages of the contact binary V2790 Ori are presented.The BV RC observations were carried out at the Thai National Observatory. The photometric light curves were fitted to provide fundamental parameters, required to examine evolutionary stages of the binary. The results indicate that V2790 Ori is a W-type contact system with a mass ratio of q = 2.932. The orbital period increase is found at a rate of d P/dt = 1.03×10^-7 d yr^-1. This implies that a rate of mass transfer from the secondary component to the primary one is dm2/dt =6.31×10^-8 M⊙yr^-1. Furthermore, we find that from the detached phase to the contact phase, the amount of mass that the evolved secondary component has lost is 1.188±0.110 M⊙, i.e., mass lost by the system is 0.789±0.073 M⊙and mass transfer to the primary is0.399±0.037 M⊙. Since the time of the first overflow, the angular momentum loss is found to be 72.2% of JFOF, causing the orbit and Roche surface to shrink until the present time.
基金supported by the National Natural Science Foundation of China (No. 11503077)
文摘Four-color charge-coupled device(CCD) light curves in the B, V, Rc and I c bands of the totaleclipsing binary system V1853 Orionis(V1853 Ori) are presented. By comparing our light curves with those published by previous investigators, it is determined that the O'Connell effect on the light curves has disappeared. By analyzing those multi-color light curves with the Wilson-Devinney code(W-D code),it is discovered that V1853 Ori is an A-type intermediate-contact binary with a degree of contact factor of f = 33.3%(3.7%) and a mass ratio of q = 0.1896(0.0013). Combining our 10 newly determined times of light minima together with others published in the literature, the period changes of the system are investigated. We found that the general trend of the observed minus calculated(O-C) curve shows a downward parabolic variation that corresponds to a long-term decrease in the orbital period with a rate of d P/dt =-1.96(0.46)×10^(-7) d yr^(-1). The long-term period decrease could be explained by mass transfer from the more-massive component to the less-massive one. By combining our photometric solutions with data from Gaia DR_2, absolute parameters were derived as M_1 = 1.20 M⊙, M_2 = 0.23 M⊙, R_1 = 1.36 R⊙and R_2 = 0.66 R⊙. The long-term period decrease and intermediate-contact configuration suggest that V1853 Ori will evolve into a high fill-out overcontact binary.
基金the National Natural Science Foundation of China(No.11873003)the Natural Science Research Key Program of Anhui Provincial Department of Education(No.kj2019A0954)+1 种基金the Outstanding Young Talents Program of Anhui Provincial Department of Education(gxgnfx2019084)the Open Project Program of the Key Laboratory of Optical Astronomy of NAOC。
文摘We present new photometry for two contact binaries,Y Sex and V1363 Ori,which were observed by three small telescopes in China.By using the W-D method,the absolute parameters are updated from new BVR light curves and previous radial velocity curves.Results identify that two binaries are deep,lowmass ratio(DLMR)overcontact binaries with q≤0.25 and f≥50%.From the temperature-luminosity diagram,the primary components are slightly evolved main-sequence stars,whose evolutionary ages are~2.51 Gyr for Y Sex and~3.56 Gyr for V 1363 Ori,respectively.From the(O-C)curves,it is found that the orbital periods may be undergoing secular increase with cyclic variations,which may be interpreted either by magnetic activity cycles or by the light-time orbit effect.With period increasing,this kind of DLMR overcontact binaries,such as Y Sex and V1363 Ori,will evolve into the rapid-rotating single stars.
基金the Scientific Research Projects Coordination Unit of Erciyes University(project number FBA–09–788)。
文摘The first photometric solution in the B,V,R_(c) and I_(c) filters of the short period V1833 Ori eclipsing binary is presented based on new ground-based CCD photometric observations.We analyzed the BVRI photometric light curves of the system,using PHOEBE 0.31 a,a binary star modeling program,with the Wilson-Devinney method based on Roche geometry to achieve the best accordance with the photometric observations to determine their absolute parameters from the light curves.We updated the ephemeris of V1833 Ori using two new light curve minima derived by our new observational data from those collected in the literature and analyzed the change of the system's orbital period.The O-C analysis indicates that the variations of the orbital period of V1833 Ori with time are increasing at a rate of 3.03×10^(-7)days yr^(-1).The distance of V1833 Ori is 173.7±15.6 pc.From the solutions,we find that V1833 Ori is an A-subtype W UMa overcontact binary with q=0.701 mass ratio and f=1.14 fill-out factor.The HR diagram positions of the eclipsing binary system's components are discussed.The system's absolute dimensions were compared to those of similar binaries in the log T_(eff)-log L,logM-logL,1 ogM-logR and logM-log J_(0)diagrams.
基金supported by the Astronomic Joint Fund of the National Natural Science Foundation of China and Chinese Academy of Sciences (U1431114,U1631236,U1631109 and 11263001)science and technology innovation team of Guizhou province(No.20154017)supported by the Natural Science Foundation of Guizhou Province Office of Education(Grant No.2014298)
文摘We obtained new high-resolution spectra using the Lijiang 1.8-m and 2.4-m telescopes to inves- tigate the chromospheric activities of V1355 Ori as indicated in the behaviors of Ca n H＆K, Hγ HT, H/3, Na1 D1, D2, Ha and Ca II infrared triplet （IRT） lines. The observed spectra show obvious emissions above the continuum in Ca II H＆K lines, absorptions in the Hδ, Hγ, H/3 and NaI D1, D2 lines, variable behavior （filled-in absorption, partial emission with a core absorption component or emission above the continuum） in the Ha line, and weak self-reversal emissions in the strong filled-in absorptions of the Ca II IRT lines. We used a spectral subtraction technique to analyze our data. The results show no excess emission in the H6 and H7 lines, very weak excess emissions in the Na I D1, D2 lines, excess emission in the H/3 line, clear excess emission in the Ha line, and excess emissions in the Ca II IRT lines. The value of the ratio of EWs542/EWsa9s is in the range 0.9 to 1.7, which implies that chromospheric activity might have been caused by plage events. The value of the ratio EHδ/EHβ is above 3, indicating that the Balmer lines would arise from prominence-like material. We also found time variations in light curves associated with equiva- lent widths of chromospheric activity lines in the Na I D1, phenomena can be explained by plage events, which are activity indicators. D2, Ca II IRT and Ha lines in particular. These consistent with the behavior of chromospheric
