The ages of coral reef samples from several shallow drill holes in the South China Sea are determined by ESR and U-series (230Th/234U) methods. The experimental results show ideal agreement between ESR and U-series ag...The ages of coral reef samples from several shallow drill holes in the South China Sea are determined by ESR and U-series (230Th/234U) methods. The experimental results show ideal agreement between ESR and U-series ages and that the coral reefs were formed in the early Holocene. In the determination of natural total dose of coral reef by use of the additive dose method good results can be obtained by exponential fitting, no matter how the effect of dose saturation is. It was found that the ratio of the natural ESR signal intensity ( I0) to the ESR signal intensity at dose saturation ( Imax) of sample can reflect the significance of a irradiation efficiency-k value. Using the k value of sample determined by the formula given in this paper, the precision of ESR dating of marine carbonates can be improved.展开更多
This paper mainly addresses maximum likelihood estimation for a response-selective stratified sampling scheme, the basic stratified sampling (BSS), in which the maximum subsample size in each stratum is fixed. We deri...This paper mainly addresses maximum likelihood estimation for a response-selective stratified sampling scheme, the basic stratified sampling (BSS), in which the maximum subsample size in each stratum is fixed. We derived the complete-data likelihood for BSS, and extended it as a full-data likelihood by incorporating incomplete data. We also similarly extended the empirical proportion likelihood approach for consistent and efficient estimation. We conducted a simulation study to compare these two new approaches with the existing estimation methods in BSS. Our result indicates that they perform as well as the standard full information likelihood approach. Methods were illustrated using a growth model for fish size at age, including between-individual variability. One of our major conclusions is that the fully observed BSS data, the partially observed data used for stratification, and the sampling strategy are all important in constructing a consistent and efficient estimator.展开更多
<strong>Background:</strong> Recently, Coronavirus Disease 2019 (COVID-19) has been affected by the extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has developed important global health a...<strong>Background:</strong> Recently, Coronavirus Disease 2019 (COVID-19) has been affected by the extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has developed important global health anxiety. At this time, the treatment options for this disease are only moderately successful. Smoking has been related to COVID-19 and its mortality, and it has the potential to affect bacteriological and viral conversion, clinical effects, and treatment outcomes. <strong>Methods:</strong> The aim of this study was to determine the relationship between critical essential trace {zinc (Zn), iron (Fe), and copper (Cu)} and toxic {cadmium (Cd) and nickel (Ni)} elements in human biological samples such as scalp hair, serum, saliva, blood, nasal fluid, and sputum of smoking and nonsmoking male COVID-19 patients (n = 139, age range 25 - 38 years) from Hyderabad, Pakistan. For comparative purposes, the biological specimens of referent persons (n = 83), pulmonary Tuberculosis (T.B) patients (n = 67), Pneumonia (n = 56) of the same age groups were also be analyzed. Microwave oven mediated digestion method was employed, and digestion of samples was carried out with the help of 2:1 mixture solution of HNO<sub>3</sub> (65%) and H<sub>2</sub>O<sub>2</sub> (30%). Atomic absorption spectrometry was employed for the determination of elemental concentrations from the microwave oven employed digested samples. <strong>Results:</strong> The found average of essential elements (Zn, Fe, and Cu) in biological specimens of smoker and nonsmoker male COVID-19, T.B, and Pneumonia patients was found to lower, whilst cadmium and nickel were found to be higher when compared with samples from referents (p < 0.001). <strong>Conclusions:</strong> Improved elemental (Cu, Fe, Zn) concentrations may also decrease the risk of bacterial co-infection by enhancing the mucociliary clearance and respiratory epithelial barrier function, in addition to providing direct antibacterial effects against <i>S. pneumoniae</i>. Our findings also suggest that higher Cd and Ni concentrations are linked to cigarette smoking, which could lead to COVID-19 and other lung-infected diseased recurrences. However, further clinical and experimental research is required.展开更多
Due to recent improvements in forensic DNA testing kit sensitivity,there has been an increased demand in the criminal justice community to revisit past convictions or cold cases.Some of these cases have little biologi...Due to recent improvements in forensic DNA testing kit sensitivity,there has been an increased demand in the criminal justice community to revisit past convictions or cold cases.Some of these cases have little biological evidence other than touch DNA in the form of archived latent fingerprint lift cards.In this study,a previously developed optimised workflow for this sample type was tested on aged fingerprints to determine if improved short tandem repeat(STR)profiles could be obtained.Two-year-old samples processed with the optimised workflow produced an average of approximately five more STR alleles per profile over the traditional method.The optimised workflow also produced detectable alleles in samples aged out to 28 years.Of the methods tested,the optimised workflow resulted in the most informative profiles from evidence samples more representative of the forensic need.This workflow is recommended for use with archived latent fingerprint samples,regardless of the archival time.展开更多
To assess the value of intravascular ultrasound in detecting carotid atherosclerosis,we compared the ultrasound images of 48 carotid artery segments from autopsies with their histological findings.The results showed t...To assess the value of intravascular ultrasound in detecting carotid atherosclerosis,we compared the ultrasound images of 48 carotid artery segments from autopsies with their histological findings.The results showed that by intravascular ultrasonography one could distinguish between elastic and展开更多
Background To investigate the relationship of age at first separation from parents(AFSP)with suicidal ideation(SI),suicide planning(SP)and suicide attempts(SA)among left-behind children(LBC)in China and the mediating ...Background To investigate the relationship of age at first separation from parents(AFSP)with suicidal ideation(SI),suicide planning(SP)and suicide attempts(SA)among left-behind children(LBC)in China and the mediating effect of traumatic events(TEs).Methods This cross-sectional study employed a multistage sampling method to conduct questionnaire surveys in six high-concentrated LBC provinces.Logistic regression and restricted cubic splines were performed to investigate the association of AFSP with SI,SP and SA,and meta-analysis(I2)was used to assess the heterogeneity.Causal mediation analysis(structural equation modelling)was used to evaluate the mediating effect of TEs,and bootstrap resampling was employed to assess the robustness of the causal mediation analysis.Results A total of 12162(6269 LBC)participants were included in this study;the prevalence rates of SI,SP and SA among LBC were 30.7%,18.6%and 11.9%;and LBC had a higher risk of SI(OR:1.32),SP(OR:1.40)and SA(OR:1.25)than non-LBC,all p<0.001.AFSP was negatively associated with SI,SP and SA,particularly peaking before 2 years old.LBC with AFSP<2 years old had a higher risk of SI(OR 2.65;95%CI 2.17 to 3.24;p<0.001),SP(OR 2.63;95%CI 3.36 to 4.29;p<0.001)and SA(OR 2.04;95%CI 2.73 to 3.63;p<0.001).TEs mediated the increased risk of SI(average causal mediation effect(ACME)0.03–0.07;proportion(Prop)40–54%;all p<0.001),SP(ACME 0.03–0.06;Prop 39–61%;all p<0.001)and SA(ACME 0.02–0.04;Prop 53–80%;all p<0.01).Conclusions We found that AFSP was associated with SI,SP and SA,mediated by TEs.Our findings supported the necessity of reducing SI,SP and SA risks among LBC and highlighted the need to consider AFSPs and TEs in intervention strategies.展开更多
Two national stalagmite standard （GBW04412, GBW04413） and one international coral standard （RKM4） have been determined by using thermal ionization mass spectrometry （TIMS） method. The values of （ 234 U/ 238 U）...Two national stalagmite standard （GBW04412, GBW04413） and one international coral standard （RKM4） have been determined by using thermal ionization mass spectrometry （TIMS） method. The values of （ 234 U/ 238 U） act , （ 230 Th/ 234 U） act and age are all consistent in error range with the standard values obtained by using α spectrometry.展开更多
Aims Neutral theory consists of a suite of models that assume ecological equivalence among individual organisms.They have been most commonly applied to tropical forest tree communities either as null models or as appr...Aims Neutral theory consists of a suite of models that assume ecological equivalence among individual organisms.They have been most commonly applied to tropical forest tree communities either as null models or as approximations.Neutral models typically only include reproductive adults;therefore,fitting to empirical tree community data requires defining a reproductive-size threshold,which for trees is usually set arbitrarily to a diameter at breast height(DBH)of 100 mm.The inevitable exclusion of some reproductive adults and inclusion of some saplings cause a non-random sampling bias in neutral model fits.Here,we investigate this problem and resolve it by introducing simple age structure into a neutral model.Methods We compared the performance and sensitivity of DBH threshold of three variants of a spatially explicit neutral model:the traditional model,a model incorporating random sampling and a model with two distinct age classes—reproductive adults and saplings.In the age-structured model,saplings are offspring from adults that disperse according to a Gaussian dispersal kernel around the adults.The only extra parameter is the ratio of adults to saplings,which is not a free parameter but directly measurable.We used species–area relationships(SARs)to explore the predicted effect of saplings on the species richness at different scales in our model.We then evaluated the three model variations to find the parameters required to maintain the observed level of species richness in the 50-ha plot on Barro Colorado Island(BCI).We repeated our analysis filtering the data at different minimum tree-size thresholds in order to find the effect this threshold has on our results.Lastly,we used empirical species–individual relationships(SIRs)to test the pre-existing hypothesis that environmental filtering is the primary cause of differences between the assemblage of saplings and that of adults on BCI.Important Findings Our age-structured neutral model was characterized by SARs that were insensitive to the presence of saplings at large scales and highly sensitive to them at small scales.Both models without age structure were highly sensitive to the DBH threshold chosen in a way that could not be explained based on random samplings alone.The age-structured neutral model,which allowed for non-random sampling based on life stage,was consistent with species richness observations.Our analysis of empirical SIRs did not support environmental filtering as a dominant force,but it did show evidence for other differences between age classes.Age can now be easily incorporated into future studies of neutral models whenever there is a concern that a sample is not entirely composed of reproductive adult individuals.More generally,we suggest that modeling studies using tree data subject to a minimum size threshold should consider the sensitivity of their results to that threshold.展开更多
In the electronic age,traditional collections of geological specimens as in museums,and bulky materials as in drill core“libraries”,lag behind the general progress as they require more space to keep and labour to ma...In the electronic age,traditional collections of geological specimens as in museums,and bulky materials as in drill core“libraries”,lag behind the general progress as they require more space to keep and labour to maintain.This results in liquidation of some established collections and near-sequestration of others so that physical access to material for study and research is severely restricted.展开更多
Background:In light of the shift to aiming for schistosomiasis elimination,the following are needed:data on reinfection patterns,participation,and sample submission adherence of all high-risk age groups to interventio...Background:In light of the shift to aiming for schistosomiasis elimination,the following are needed:data on reinfection patterns,participation,and sample submission adherence of all high-risk age groups to intervention strategies.This study was conducted to assess prevalence,reinfections along with consecutive participation,sample submission adherence,and effect of treatment on schistosomiasis prevalence in children aged five years and below in an endemic district in Zimbabwe,over one year.Methods:The study was conducted from February 2016-February 2017 in Madziwa area,Shamva district.Following community mobilisation,mothers brought their children aged 5 years and below for recruitment at baseline and also urine sample collection at baseline,3,6,9 and 12 months follow up surveys.At each time point,urine was tested for urogenital schistosomiasis by urine filtration and children found positive received treatment.Schistosoma haematobium prevalence,reinfections as well as children participation,and urine sample submission at each visit were assessed at each time point for one year.Results:Of the 535 children recruited from the five communities,169(31.6%)participated consecutively at all survey points.The highest mean number of samples submitted was 2.9 among communities and survey points.S.haematobium prevalence significantly reduced from 13.3%at baseline to 2.8%at 12 months for all participants and from 24.9%at baseline to 1.8%at 12 months(P<0.001)for participants coming at all-time points.Among the communities,the highest baseline prevalence was found in Chihuri for both the participants coming consecutively(38.5%,10/26)and all participants(20.4%,21/103).Reinfections were significantly high at 9 months follow up survey(P=0.021)and in Mupfure(P=0.003).New infections significantly decreased over time(P<0.001).Logistic regression analysis showed that the risk of acquiring schistosomiasis was high in some communities(P<0.05).Conclusions:S.haematobium infections and reinfections are seasonal and depend on micro-geographical settings.The risk of being infected with schistosomes in pre-school aged children increases with increasing age.Sustained treatment of infected individuals in a community reduces prevalence overtime.Participation compliance at consecutive visits and sample submission adherence are important for effective operational control interventions.展开更多
Traumatic tricuspid valve insufficiency (TTVI) is a relatively uncommon disease. To summarize the experience in the diagnosis and treatment of TTVI, we have analyzed the clinical data of 3 patients with TTVI who were ...Traumatic tricuspid valve insufficiency (TTVI) is a relatively uncommon disease. To summarize the experience in the diagnosis and treatment of TTVI, we have analyzed the clinical data of 3 patients with TTVI who were admitted to the department of cardiac surgery of our hospital between April 1997 to April 2002. Relevant literatures have also been reviewed.展开更多
文摘The ages of coral reef samples from several shallow drill holes in the South China Sea are determined by ESR and U-series (230Th/234U) methods. The experimental results show ideal agreement between ESR and U-series ages and that the coral reefs were formed in the early Holocene. In the determination of natural total dose of coral reef by use of the additive dose method good results can be obtained by exponential fitting, no matter how the effect of dose saturation is. It was found that the ratio of the natural ESR signal intensity ( I0) to the ESR signal intensity at dose saturation ( Imax) of sample can reflect the significance of a irradiation efficiency-k value. Using the k value of sample determined by the formula given in this paper, the precision of ESR dating of marine carbonates can be improved.
文摘This paper mainly addresses maximum likelihood estimation for a response-selective stratified sampling scheme, the basic stratified sampling (BSS), in which the maximum subsample size in each stratum is fixed. We derived the complete-data likelihood for BSS, and extended it as a full-data likelihood by incorporating incomplete data. We also similarly extended the empirical proportion likelihood approach for consistent and efficient estimation. We conducted a simulation study to compare these two new approaches with the existing estimation methods in BSS. Our result indicates that they perform as well as the standard full information likelihood approach. Methods were illustrated using a growth model for fish size at age, including between-individual variability. One of our major conclusions is that the fully observed BSS data, the partially observed data used for stratification, and the sampling strategy are all important in constructing a consistent and efficient estimator.
文摘<strong>Background:</strong> Recently, Coronavirus Disease 2019 (COVID-19) has been affected by the extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has developed important global health anxiety. At this time, the treatment options for this disease are only moderately successful. Smoking has been related to COVID-19 and its mortality, and it has the potential to affect bacteriological and viral conversion, clinical effects, and treatment outcomes. <strong>Methods:</strong> The aim of this study was to determine the relationship between critical essential trace {zinc (Zn), iron (Fe), and copper (Cu)} and toxic {cadmium (Cd) and nickel (Ni)} elements in human biological samples such as scalp hair, serum, saliva, blood, nasal fluid, and sputum of smoking and nonsmoking male COVID-19 patients (n = 139, age range 25 - 38 years) from Hyderabad, Pakistan. For comparative purposes, the biological specimens of referent persons (n = 83), pulmonary Tuberculosis (T.B) patients (n = 67), Pneumonia (n = 56) of the same age groups were also be analyzed. Microwave oven mediated digestion method was employed, and digestion of samples was carried out with the help of 2:1 mixture solution of HNO<sub>3</sub> (65%) and H<sub>2</sub>O<sub>2</sub> (30%). Atomic absorption spectrometry was employed for the determination of elemental concentrations from the microwave oven employed digested samples. <strong>Results:</strong> The found average of essential elements (Zn, Fe, and Cu) in biological specimens of smoker and nonsmoker male COVID-19, T.B, and Pneumonia patients was found to lower, whilst cadmium and nickel were found to be higher when compared with samples from referents (p < 0.001). <strong>Conclusions:</strong> Improved elemental (Cu, Fe, Zn) concentrations may also decrease the risk of bacterial co-infection by enhancing the mucociliary clearance and respiratory epithelial barrier function, in addition to providing direct antibacterial effects against <i>S. pneumoniae</i>. Our findings also suggest that higher Cd and Ni concentrations are linked to cigarette smoking, which could lead to COVID-19 and other lung-infected diseased recurrences. However, further clinical and experimental research is required.
基金This work was supported by the Department of Forensic Science of Virgina Commonwealth University and National Institute of Justice(NIJ)Award 2014-DNBX-K013.
文摘Due to recent improvements in forensic DNA testing kit sensitivity,there has been an increased demand in the criminal justice community to revisit past convictions or cold cases.Some of these cases have little biological evidence other than touch DNA in the form of archived latent fingerprint lift cards.In this study,a previously developed optimised workflow for this sample type was tested on aged fingerprints to determine if improved short tandem repeat(STR)profiles could be obtained.Two-year-old samples processed with the optimised workflow produced an average of approximately five more STR alleles per profile over the traditional method.The optimised workflow also produced detectable alleles in samples aged out to 28 years.Of the methods tested,the optimised workflow resulted in the most informative profiles from evidence samples more representative of the forensic need.This workflow is recommended for use with archived latent fingerprint samples,regardless of the archival time.
文摘To assess the value of intravascular ultrasound in detecting carotid atherosclerosis,we compared the ultrasound images of 48 carotid artery segments from autopsies with their histological findings.The results showed that by intravascular ultrasonography one could distinguish between elastic and
基金supported by the National Social Science Fund of China(NSSFC)(Grant No 20BSH066,JZ).
文摘Background To investigate the relationship of age at first separation from parents(AFSP)with suicidal ideation(SI),suicide planning(SP)and suicide attempts(SA)among left-behind children(LBC)in China and the mediating effect of traumatic events(TEs).Methods This cross-sectional study employed a multistage sampling method to conduct questionnaire surveys in six high-concentrated LBC provinces.Logistic regression and restricted cubic splines were performed to investigate the association of AFSP with SI,SP and SA,and meta-analysis(I2)was used to assess the heterogeneity.Causal mediation analysis(structural equation modelling)was used to evaluate the mediating effect of TEs,and bootstrap resampling was employed to assess the robustness of the causal mediation analysis.Results A total of 12162(6269 LBC)participants were included in this study;the prevalence rates of SI,SP and SA among LBC were 30.7%,18.6%and 11.9%;and LBC had a higher risk of SI(OR:1.32),SP(OR:1.40)and SA(OR:1.25)than non-LBC,all p<0.001.AFSP was negatively associated with SI,SP and SA,particularly peaking before 2 years old.LBC with AFSP<2 years old had a higher risk of SI(OR 2.65;95%CI 2.17 to 3.24;p<0.001),SP(OR 2.63;95%CI 3.36 to 4.29;p<0.001)and SA(OR 2.04;95%CI 2.73 to 3.63;p<0.001).TEs mediated the increased risk of SI(average causal mediation effect(ACME)0.03–0.07;proportion(Prop)40–54%;all p<0.001),SP(ACME 0.03–0.06;Prop 39–61%;all p<0.001)and SA(ACME 0.02–0.04;Prop 53–80%;all p<0.01).Conclusions We found that AFSP was associated with SI,SP and SA,mediated by TEs.Our findings supported the necessity of reducing SI,SP and SA risks among LBC and highlighted the need to consider AFSPs and TEs in intervention strategies.
文摘Two national stalagmite standard （GBW04412, GBW04413） and one international coral standard （RKM4） have been determined by using thermal ionization mass spectrometry （TIMS） method. The values of （ 234 U/ 238 U） act , （ 230 Th/ 234 U） act and age are all consistent in error range with the standard values obtained by using α spectrometry.
基金Engineering and Physical Sciences Research Council overseas postdoctoral research fellowship at the life sciences interface(EP/F043112/1 to J.R.)the Netherlands Organization for Scientific Research(NWO-ALW 864-07-007 to R.S.E.,NWOALW 863-07-008 to P.A.J.).
文摘Aims Neutral theory consists of a suite of models that assume ecological equivalence among individual organisms.They have been most commonly applied to tropical forest tree communities either as null models or as approximations.Neutral models typically only include reproductive adults;therefore,fitting to empirical tree community data requires defining a reproductive-size threshold,which for trees is usually set arbitrarily to a diameter at breast height(DBH)of 100 mm.The inevitable exclusion of some reproductive adults and inclusion of some saplings cause a non-random sampling bias in neutral model fits.Here,we investigate this problem and resolve it by introducing simple age structure into a neutral model.Methods We compared the performance and sensitivity of DBH threshold of three variants of a spatially explicit neutral model:the traditional model,a model incorporating random sampling and a model with two distinct age classes—reproductive adults and saplings.In the age-structured model,saplings are offspring from adults that disperse according to a Gaussian dispersal kernel around the adults.The only extra parameter is the ratio of adults to saplings,which is not a free parameter but directly measurable.We used species–area relationships(SARs)to explore the predicted effect of saplings on the species richness at different scales in our model.We then evaluated the three model variations to find the parameters required to maintain the observed level of species richness in the 50-ha plot on Barro Colorado Island(BCI).We repeated our analysis filtering the data at different minimum tree-size thresholds in order to find the effect this threshold has on our results.Lastly,we used empirical species–individual relationships(SIRs)to test the pre-existing hypothesis that environmental filtering is the primary cause of differences between the assemblage of saplings and that of adults on BCI.Important Findings Our age-structured neutral model was characterized by SARs that were insensitive to the presence of saplings at large scales and highly sensitive to them at small scales.Both models without age structure were highly sensitive to the DBH threshold chosen in a way that could not be explained based on random samplings alone.The age-structured neutral model,which allowed for non-random sampling based on life stage,was consistent with species richness observations.Our analysis of empirical SIRs did not support environmental filtering as a dominant force,but it did show evidence for other differences between age classes.Age can now be easily incorporated into future studies of neutral models whenever there is a concern that a sample is not entirely composed of reproductive adult individuals.More generally,we suggest that modeling studies using tree data subject to a minimum size threshold should consider the sensitivity of their results to that threshold.
文摘In the electronic age,traditional collections of geological specimens as in museums,and bulky materials as in drill core“libraries”,lag behind the general progress as they require more space to keep and labour to maintain.This results in liquidation of some established collections and near-sequestration of others so that physical access to material for study and research is severely restricted.
基金This study was partly funded by Thrasher foundation(No.12440).
文摘Background:In light of the shift to aiming for schistosomiasis elimination,the following are needed:data on reinfection patterns,participation,and sample submission adherence of all high-risk age groups to intervention strategies.This study was conducted to assess prevalence,reinfections along with consecutive participation,sample submission adherence,and effect of treatment on schistosomiasis prevalence in children aged five years and below in an endemic district in Zimbabwe,over one year.Methods:The study was conducted from February 2016-February 2017 in Madziwa area,Shamva district.Following community mobilisation,mothers brought their children aged 5 years and below for recruitment at baseline and also urine sample collection at baseline,3,6,9 and 12 months follow up surveys.At each time point,urine was tested for urogenital schistosomiasis by urine filtration and children found positive received treatment.Schistosoma haematobium prevalence,reinfections as well as children participation,and urine sample submission at each visit were assessed at each time point for one year.Results:Of the 535 children recruited from the five communities,169(31.6%)participated consecutively at all survey points.The highest mean number of samples submitted was 2.9 among communities and survey points.S.haematobium prevalence significantly reduced from 13.3%at baseline to 2.8%at 12 months for all participants and from 24.9%at baseline to 1.8%at 12 months(P<0.001)for participants coming at all-time points.Among the communities,the highest baseline prevalence was found in Chihuri for both the participants coming consecutively(38.5%,10/26)and all participants(20.4%,21/103).Reinfections were significantly high at 9 months follow up survey(P=0.021)and in Mupfure(P=0.003).New infections significantly decreased over time(P<0.001).Logistic regression analysis showed that the risk of acquiring schistosomiasis was high in some communities(P<0.05).Conclusions:S.haematobium infections and reinfections are seasonal and depend on micro-geographical settings.The risk of being infected with schistosomes in pre-school aged children increases with increasing age.Sustained treatment of infected individuals in a community reduces prevalence overtime.Participation compliance at consecutive visits and sample submission adherence are important for effective operational control interventions.
文摘Traumatic tricuspid valve insufficiency (TTVI) is a relatively uncommon disease. To summarize the experience in the diagnosis and treatment of TTVI, we have analyzed the clinical data of 3 patients with TTVI who were admitted to the department of cardiac surgery of our hospital between April 1997 to April 2002. Relevant literatures have also been reviewed.
