The microbial reduction of ferrihydrite,lepidocrocite,hematite,goethite and aluminum-substituted iron oxides were examined by iron-reducer GS-15 under anaerobic pure culture condition.The results indicated that the fe...The microbial reduction of ferrihydrite,lepidocrocite,hematite,goethite and aluminum-substituted iron oxides were examined by iron-reducer GS-15 under anaerobic pure culture condition.The results indicated that the ferrihydrite and lepidocrocite can be rapidly reduced by iron-reducer,and the percentage of microbial reduction are respectively 95.4% and 95.8% after 4 days incubation at 25℃.The other iron oxides like hematite,Al-hematite,goethite and Al-goethite are very difficult to reduce during short-term incubation.The amounts of Fe(Ⅲ)-reducing,Fe(Ⅱ)-producing and Fe-reducing calculated by acetate consumption are identical under the conditions of lower concentration iron oxides addition.展开更多
This paper focuses on the use of models for increasing the precision of estimators in large-area forest surveys. It is motivated by the increasing availability of remotely sensed data, which facilitates the developmen...This paper focuses on the use of models for increasing the precision of estimators in large-area forest surveys. It is motivated by the increasing availability of remotely sensed data, which facilitates the development of models predicting the variables of interest in forest surveys. We present, review and compare three different estimation frameworks where models play a core role： model-assisted, model-based, and hybrid estimation. The first two are well known, whereas the third has only recently been introduced in forest surveys. Hybrid inference mixes design- based and model-based inference, since it relies on a probability sample of auxiliary data and a model predicting the target variable from the auxiliary data.We review studies on large-area forest surveys based on model-assisted, model- based, and hybrid estimation, and discuss advantages and disadvantages of the approaches. We conclude that no general recommendations can be made about whether model-assisted, model-based, or hybrid estimation should be preferred. The choice depends on the objective of the survey and the possibilities to acquire appropriate field and remotely sensed data. We also conclude that modelling approaches can only be successfully applied for estimating target variables such as growing stock volume or biomass, which are adequately related to commonly available remotely sensed data, and thus purely field based surveys remain important for several important forest parameters.展开更多
Background CH<sub>4</sub> concentration and seasonal variations measured at Zhongshan Station (69°22'2''S, 76°21'49''E, 18.5 m) in Antarctica from 2008 through 2013 are pr...Background CH<sub>4</sub> concentration and seasonal variations measured at Zhongshan Station (69°22'2''S, 76°21'49''E, 18.5 m) in Antarctica from 2008 through 2013 are presented and discussed. From 2008-2013 CH<sub>4</sub> was measured in weekly<sub> </sub>flask samples and started on line measurement by Picarro CO<sub>2</sub>/CH<sub>4</sub>/H<sub>2</sub>O analyzer from March, 2010-2013. These CH<sub>4</sub> measurements show the expected growth period of CH<sub>4</sub> concentration during February (Antarctic spring) with a peak in September (fall). Irrespective of wind direction, CH<sub>4</sub> concentrations distribute evenly after the removal of polluted air from station operations, accounting for 1% of the data. The mean daily cycle of CH<sub>4</sub> concentration in all four seasons is small. The monthly mean CH<sub>4</sub> concentration at Zhongshan station is similar to those at other stations in Antarctica showing that CH<sub>4</sub> observed in Antarctica is fully mixed in the atmosphere as it is transported from the northern through the southern hemisphere. The annual CH<sub>4</sub> increase in recent years at Zhongshan station is 4.8 ppb·yr<sup>-1</sup>.展开更多
Background: The effect of traffic related emissions on Heart Rate Variability (HRV) has been previously demonstrated. However, the results of different studies on the relationship between ambient pollutants and specif...Background: The effect of traffic related emissions on Heart Rate Variability (HRV) has been previously demonstrated. However, the results of different studies on the relationship between ambient pollutants and specifically carbon monoxide (CO) on HRV are inconclusive and appear to reflect personal differences. The differences in methodology including breathing style and participants under study can possibly attribute to this variability. The aim of the present study is to assess the effect of the breathing route (Nasal/Oral) on the relationship between CO concentration and HRV. Methodology: Forty healthy participants (25 females, 15 males) between the ages of 15 - 50 years were included in the study. The participants strolled in a central bus station, staying for 10 minutes in three designated locations alternating nasal and oral breathing. CO concentration and HRV were continuously monitored. Frequency (LnLF, LnHF, LnLF/HF) and time domain (LnSDNN, LnRMSSD) HRV indices were computed. Analysis: MANCOVA, with HRV indices being the dependent variables and CO, gender and age being the independent variables was employed. Results: Significant interaction effects between breathing route and CO, and breathing route and gender on HRV (LnLF/HF) were found (p = 0.04 and 0.01 respectively). Both CO and age were found to affect LnSDNN and LnRMSSD. Conclusion: Breathing route emerges as a possible modifier of the relationship between air pollution and HRV and thus contributes to interpersonal differences obtained in studies investigating the effect of environmental pollution and HRV.展开更多
Background:Large area forest inventories often use regular grids(with a single random start)of sample locations to ensure a uniform sampling intensity across the space of the surveyed populations.A design-unbiased est...Background:Large area forest inventories often use regular grids(with a single random start)of sample locations to ensure a uniform sampling intensity across the space of the surveyed populations.A design-unbiased estimator of variance does not exist for this design.Oftentimes,a quasi-default estimator applicable to simple random sampling(SRS)is used,even if it carries with it the likely risk of overestimating the variance by a practically important margin.To better exploit the precision of systematic sampling we assess the performance of five estimators of variance,including the quasi default.In this study,simulated systematic sampling was applied to artificial populations with contrasting covariance structures and with or without linear trends.We compared the results obtained with the SRS,Matern’s,successive difference replication,Ripley’s,and D’Orazio’s variance estimators.Results:The variances obtained with the four alternatives to the SRS estimator of variance were strongly correlated,and in all study settings consistently closer to the target design variance than the estimator for SRS.The latter always produced the greatest overestimation.In populations with a near zero spatial autocorrelation,all estimators,performed equally,and delivered estimates close to the actual design variance.Conclusion:Without a linear trend,the SDR and DOR estimators were best with variance estimates more narrowly distributed around the benchmark;yet in terms of the least average absolute deviation,Matern’s estimator held a narrow lead.With a strong or moderate linear trend,Matern’s estimator is choice.In large populations,and a low sampling intensity,the performance of the investigated estimators becomes more similar.展开更多
The integration of gallium nitride(GaN)nanowire light-emitting diodes(nanoLEDs)on flexible substrates offers opportunities for applications beyond rigid solid-state lighting(e.g.,for wearable optoelectronics and benda...The integration of gallium nitride(GaN)nanowire light-emitting diodes(nanoLEDs)on flexible substrates offers opportunities for applications beyond rigid solid-state lighting(e.g.,for wearable optoelectronics and bendable inorganic displays).Here,we report on a fast physical transfer route based on femtosecond laser lift-off(fs-LLO)to realize wafer-scale top–down GaN nanoLED arrays on unconventional platforms.Combined with photolithography and hybrid etching processes,we successfully transferred GaN blue nanoLEDs from a full two-inch sapphire substrate onto a flexible copper(Cu)foil with a high nanowire density(~107 wires/cm2),transfer yield(~99.5%),and reproducibility.Various nanoanalytical measurements were conducted to evaluate the performance and limitations of the fs-LLO technique as well as to gain insights into physical material properties such as strain relaxation and assess the maturity of the transfer process.This work could enable the easy recycling of native growth substrates and inspire the development of large-scale hybrid GaN nanowire optoelectronic devices by solely employing standard epitaxial LED wafers(i.e.,customized LED wafers with additional embedded sacrificial materials and a complicated growth process are not required).展开更多
The electromagnetic interaction of light with polar materials shows a sharp and well defined electromagnetic response in the infrared(IR)region that consists mainly of excitation of optical phonons.Similar to surface ...The electromagnetic interaction of light with polar materials shows a sharp and well defined electromagnetic response in the infrared(IR)region that consists mainly of excitation of optical phonons.Similar to surface plasmons in the visible region,surface phonons can couple efficiently to infrared light in micron-sized antennas made of polar materials.We applied the boundary element method to calculating the infrared electromagnetic response of single SiC disks acting as effective infrared antennas as a function of different parameters such as disk size and thickness.We also analyzed the effect of locating a probing metallic tip near the SiC disk to scatter light in the proximity of the SiC disk,thereby obtaining new spectral peaks connected with localized modes between the tip and the SiC disk.We then further investigated their application in IR scanning probe microscopy.A near-field map of the phononic resonances enhances the understanding of the nature of the IR extinction peaks.展开更多
Background:Strength-trained athletes using anabolic androgenic steroids(AAS)have left ventricular(LV)hypertrophy and myocardial fibrosis that can lead to sudden cardiac death.A similar feature was described in athlete...Background:Strength-trained athletes using anabolic androgenic steroids(AAS)have left ventricular(LV)hypertrophy and myocardial fibrosis that can lead to sudden cardiac death.A similar feature was described in athletes with hypertrophic cardiomyopathy(HCM),which complicates the diagnosis for clinicians.In this context,we aimed to compare the LV function of the 2 populations by measuring global and regional strain and myocardial work using speckle-tracking imaging.Methods:Twenty-four strength-trained asymptomatic athletes using AAS(AAS-Athletes),22 athletes diagnosed with HCM(HCM-Athletes),and 20 healthy control athletes(Ctrl-Athletes)underwent a resting echocardiography to assess LV function.We evaluated LV global and regional strains and myocardial work,with an evaluation of the constructive work(CW),wasted work,and work efficiency(WE).Results:Compared to Ctrl-Athletes,both AAS-Athletes and HCM-Athletes had a thicker interventricular septum,with maj ored values in HCM-Athletes.LV strain was reduced in AAS-Athletes and even more in HCM-Athletes.Consequently,global WE was significantly diminished in both AAS and HCM-Athletes(93%±2%in Ctrl-Athletes,90%±4%in AAS-Athletes,and 90%±5%in HCM-Athletes(mean±SD);p<0.05).Constructive work and WE regional analysis showed specific alterations,with the basal septal segments preferentially affected in AAS-Athletes,and both septal and apical segments affected in HCM-Athletes.Conclusion:The regional evaluation of myocardial work reported specific alterations of the major LV hypertrophy induced by the regular use of AAS compared to the LV hypertrophy due to HCM.This finding could help clinicians to differentiate between these 2 forms of pathological hypertrophy.展开更多
介绍了ABB对Hi Pak 6500V/750A IGBT模块反向恢复特性的研究,首创性地就di/dt对二极管和与之反向并联的IGBT的正、反向恢复特性的影响进行了研究;并分析了di/dt对IGBT模块的影响,可以确认di/dt在其反向恢复过程中起重要作用,即当di/dt...介绍了ABB对Hi Pak 6500V/750A IGBT模块反向恢复特性的研究,首创性地就di/dt对二极管和与之反向并联的IGBT的正、反向恢复特性的影响进行了研究;并分析了di/dt对IGBT模块的影响,可以确认di/dt在其反向恢复过程中起重要作用,即当di/dt过高时,IGBT和二极管芯片会发生损坏,并有可能随后导致变流器的桥臂间短路。文章指出IGBT和门极驱动之间的优化匹配对确保安全工作十分重要,只有这样Hi Pak模块的鲁棒性才能得以完全体现。展开更多
Overweight and obesity in children are an increasing public health problem,and the influence the gut microbiota has on it,is still discussed.The consumption of prebiotics has been studied in children with overweight a...Overweight and obesity in children are an increasing public health problem,and the influence the gut microbiota has on it,is still discussed.The consumption of prebiotics has been studied in children with overweight and obesity after an intervention with fermented milk,supplemented with different fructans like prebiotics,was carried out to obtain a healthy microbiota.Children were randomly assigned into three groups,a double-blind intervention was carried out,receiving different fermented milk products for 6 weeks,including the following supplements:Lactobacillus casei strain Shirota,L.casei strain Shirota with inulin or L.casei strain Shirota with fructans from Agave salmiana Otto ex Salm-Dyck.DNA was extracted from stool samples and the differential abundance of ASV was monitored by high throughput 16S rRNA gene sequencing.A synbiotic with fructans from A.salmiana stimulated the abundance and diversity of the microbiota,specifically on genera Faecalibacterium and Holdemanella,thus,leading to a healthier gut microbiota,which led to obtaining the best anthropometric changes in synbiotic groups.Synbiotic intervention may provide health benefits to children with overweight or obesity by increasing the richness of the gut microbiota and stimulate beneficial bacteria.Nevertheless,more studies are needed to get a better understanding of the mechanisms of action.展开更多
This paper conveys a cross-cultural understanding of the Chinese "Belt and Road Initiative"(BRI)using principles of western rhetoric as basis for inter- pretation.Thus,an American perspective is stressed.Mos...This paper conveys a cross-cultural understanding of the Chinese "Belt and Road Initiative"(BRI)using principles of western rhetoric as basis for inter- pretation.Thus,an American perspective is stressed.Most specifically,Kenneth Burke's Dramatistic Pentad is used for initial clarification along with the explana- tion of how further understanding can be realized via Fantasy Theme Analysis to better appreciate the expression of rhetorical vision.Recognition of how BRI can be understood differently,depending on the cultural context,is emphasized.This is couched in the contextual framing of mass media influences as explained by Marshall McLuhan.展开更多
文摘The microbial reduction of ferrihydrite,lepidocrocite,hematite,goethite and aluminum-substituted iron oxides were examined by iron-reducer GS-15 under anaerobic pure culture condition.The results indicated that the ferrihydrite and lepidocrocite can be rapidly reduced by iron-reducer,and the percentage of microbial reduction are respectively 95.4% and 95.8% after 4 days incubation at 25℃.The other iron oxides like hematite,Al-hematite,goethite and Al-goethite are very difficult to reduce during short-term incubation.The amounts of Fe(Ⅲ)-reducing,Fe(Ⅱ)-producing and Fe-reducing calculated by acetate consumption are identical under the conditions of lower concentration iron oxides addition.
文摘This paper focuses on the use of models for increasing the precision of estimators in large-area forest surveys. It is motivated by the increasing availability of remotely sensed data, which facilitates the development of models predicting the variables of interest in forest surveys. We present, review and compare three different estimation frameworks where models play a core role： model-assisted, model-based, and hybrid estimation. The first two are well known, whereas the third has only recently been introduced in forest surveys. Hybrid inference mixes design- based and model-based inference, since it relies on a probability sample of auxiliary data and a model predicting the target variable from the auxiliary data.We review studies on large-area forest surveys based on model-assisted, model- based, and hybrid estimation, and discuss advantages and disadvantages of the approaches. We conclude that no general recommendations can be made about whether model-assisted, model-based, or hybrid estimation should be preferred. The choice depends on the objective of the survey and the possibilities to acquire appropriate field and remotely sensed data. We also conclude that modelling approaches can only be successfully applied for estimating target variables such as growing stock volume or biomass, which are adequately related to commonly available remotely sensed data, and thus purely field based surveys remain important for several important forest parameters.
文摘Background CH<sub>4</sub> concentration and seasonal variations measured at Zhongshan Station (69°22'2''S, 76°21'49''E, 18.5 m) in Antarctica from 2008 through 2013 are presented and discussed. From 2008-2013 CH<sub>4</sub> was measured in weekly<sub> </sub>flask samples and started on line measurement by Picarro CO<sub>2</sub>/CH<sub>4</sub>/H<sub>2</sub>O analyzer from March, 2010-2013. These CH<sub>4</sub> measurements show the expected growth period of CH<sub>4</sub> concentration during February (Antarctic spring) with a peak in September (fall). Irrespective of wind direction, CH<sub>4</sub> concentrations distribute evenly after the removal of polluted air from station operations, accounting for 1% of the data. The mean daily cycle of CH<sub>4</sub> concentration in all four seasons is small. The monthly mean CH<sub>4</sub> concentration at Zhongshan station is similar to those at other stations in Antarctica showing that CH<sub>4</sub> observed in Antarctica is fully mixed in the atmosphere as it is transported from the northern through the southern hemisphere. The annual CH<sub>4</sub> increase in recent years at Zhongshan station is 4.8 ppb·yr<sup>-1</sup>.
文摘Background: The effect of traffic related emissions on Heart Rate Variability (HRV) has been previously demonstrated. However, the results of different studies on the relationship between ambient pollutants and specifically carbon monoxide (CO) on HRV are inconclusive and appear to reflect personal differences. The differences in methodology including breathing style and participants under study can possibly attribute to this variability. The aim of the present study is to assess the effect of the breathing route (Nasal/Oral) on the relationship between CO concentration and HRV. Methodology: Forty healthy participants (25 females, 15 males) between the ages of 15 - 50 years were included in the study. The participants strolled in a central bus station, staying for 10 minutes in three designated locations alternating nasal and oral breathing. CO concentration and HRV were continuously monitored. Frequency (LnLF, LnHF, LnLF/HF) and time domain (LnSDNN, LnRMSSD) HRV indices were computed. Analysis: MANCOVA, with HRV indices being the dependent variables and CO, gender and age being the independent variables was employed. Results: Significant interaction effects between breathing route and CO, and breathing route and gender on HRV (LnLF/HF) were found (p = 0.04 and 0.01 respectively). Both CO and age were found to affect LnSDNN and LnRMSSD. Conclusion: Breathing route emerges as a possible modifier of the relationship between air pollution and HRV and thus contributes to interpersonal differences obtained in studies investigating the effect of environmental pollution and HRV.
文摘Background:Large area forest inventories often use regular grids(with a single random start)of sample locations to ensure a uniform sampling intensity across the space of the surveyed populations.A design-unbiased estimator of variance does not exist for this design.Oftentimes,a quasi-default estimator applicable to simple random sampling(SRS)is used,even if it carries with it the likely risk of overestimating the variance by a practically important margin.To better exploit the precision of systematic sampling we assess the performance of five estimators of variance,including the quasi default.In this study,simulated systematic sampling was applied to artificial populations with contrasting covariance structures and with or without linear trends.We compared the results obtained with the SRS,Matern’s,successive difference replication,Ripley’s,and D’Orazio’s variance estimators.Results:The variances obtained with the four alternatives to the SRS estimator of variance were strongly correlated,and in all study settings consistently closer to the target design variance than the estimator for SRS.The latter always produced the greatest overestimation.In populations with a near zero spatial autocorrelation,all estimators,performed equally,and delivered estimates close to the actual design variance.Conclusion:Without a linear trend,the SDR and DOR estimators were best with variance estimates more narrowly distributed around the benchmark;yet in terms of the least average absolute deviation,Matern’s estimator held a narrow lead.With a strong or moderate linear trend,Matern’s estimator is choice.In large populations,and a low sampling intensity,the performance of the investigated estimators becomes more similar.
文摘The integration of gallium nitride(GaN)nanowire light-emitting diodes(nanoLEDs)on flexible substrates offers opportunities for applications beyond rigid solid-state lighting(e.g.,for wearable optoelectronics and bendable inorganic displays).Here,we report on a fast physical transfer route based on femtosecond laser lift-off(fs-LLO)to realize wafer-scale top–down GaN nanoLED arrays on unconventional platforms.Combined with photolithography and hybrid etching processes,we successfully transferred GaN blue nanoLEDs from a full two-inch sapphire substrate onto a flexible copper(Cu)foil with a high nanowire density(~107 wires/cm2),transfer yield(~99.5%),and reproducibility.Various nanoanalytical measurements were conducted to evaluate the performance and limitations of the fs-LLO technique as well as to gain insights into physical material properties such as strain relaxation and assess the maturity of the transfer process.This work could enable the easy recycling of native growth substrates and inspire the development of large-scale hybrid GaN nanowire optoelectronic devices by solely employing standard epitaxial LED wafers(i.e.,customized LED wafers with additional embedded sacrificial materials and a complicated growth process are not required).
文摘The electromagnetic interaction of light with polar materials shows a sharp and well defined electromagnetic response in the infrared(IR)region that consists mainly of excitation of optical phonons.Similar to surface plasmons in the visible region,surface phonons can couple efficiently to infrared light in micron-sized antennas made of polar materials.We applied the boundary element method to calculating the infrared electromagnetic response of single SiC disks acting as effective infrared antennas as a function of different parameters such as disk size and thickness.We also analyzed the effect of locating a probing metallic tip near the SiC disk to scatter light in the proximity of the SiC disk,thereby obtaining new spectral peaks connected with localized modes between the tip and the SiC disk.We then further investigated their application in IR scanning probe microscopy.A near-field map of the phononic resonances enhances the understanding of the nature of the IR extinction peaks.
基金supported by YAKHA Sport,Franceby the Platform 3A,funded by the European Regional Development Fund+3 种基金the French Ministry of Research,Higher Education and Innovationthe Provence-Alpes-Côte-d'Azur regionthe Departmental Council of Vauclusethe Urban Community of Avignon。
文摘Background:Strength-trained athletes using anabolic androgenic steroids(AAS)have left ventricular(LV)hypertrophy and myocardial fibrosis that can lead to sudden cardiac death.A similar feature was described in athletes with hypertrophic cardiomyopathy(HCM),which complicates the diagnosis for clinicians.In this context,we aimed to compare the LV function of the 2 populations by measuring global and regional strain and myocardial work using speckle-tracking imaging.Methods:Twenty-four strength-trained asymptomatic athletes using AAS(AAS-Athletes),22 athletes diagnosed with HCM(HCM-Athletes),and 20 healthy control athletes(Ctrl-Athletes)underwent a resting echocardiography to assess LV function.We evaluated LV global and regional strains and myocardial work,with an evaluation of the constructive work(CW),wasted work,and work efficiency(WE).Results:Compared to Ctrl-Athletes,both AAS-Athletes and HCM-Athletes had a thicker interventricular septum,with maj ored values in HCM-Athletes.LV strain was reduced in AAS-Athletes and even more in HCM-Athletes.Consequently,global WE was significantly diminished in both AAS and HCM-Athletes(93%±2%in Ctrl-Athletes,90%±4%in AAS-Athletes,and 90%±5%in HCM-Athletes(mean±SD);p<0.05).Constructive work and WE regional analysis showed specific alterations,with the basal septal segments preferentially affected in AAS-Athletes,and both septal and apical segments affected in HCM-Athletes.Conclusion:The regional evaluation of myocardial work reported specific alterations of the major LV hypertrophy induced by the regular use of AAS compared to the LV hypertrophy due to HCM.This finding could help clinicians to differentiate between these 2 forms of pathological hypertrophy.
文摘介绍了ABB对Hi Pak 6500V/750A IGBT模块反向恢复特性的研究,首创性地就di/dt对二极管和与之反向并联的IGBT的正、反向恢复特性的影响进行了研究;并分析了di/dt对IGBT模块的影响,可以确认di/dt在其反向恢复过程中起重要作用,即当di/dt过高时,IGBT和二极管芯片会发生损坏,并有可能随后导致变流器的桥臂间短路。文章指出IGBT和门极驱动之间的优化匹配对确保安全工作十分重要,只有这样Hi Pak模块的鲁棒性才能得以完全体现。
基金Thanks to Professor Celia Aradillas for the entailment with the education authorities of the full-time school program,as well as,to the company Yakult S.A.de C.V.,for providing the dairy products used in research.
文摘Overweight and obesity in children are an increasing public health problem,and the influence the gut microbiota has on it,is still discussed.The consumption of prebiotics has been studied in children with overweight and obesity after an intervention with fermented milk,supplemented with different fructans like prebiotics,was carried out to obtain a healthy microbiota.Children were randomly assigned into three groups,a double-blind intervention was carried out,receiving different fermented milk products for 6 weeks,including the following supplements:Lactobacillus casei strain Shirota,L.casei strain Shirota with inulin or L.casei strain Shirota with fructans from Agave salmiana Otto ex Salm-Dyck.DNA was extracted from stool samples and the differential abundance of ASV was monitored by high throughput 16S rRNA gene sequencing.A synbiotic with fructans from A.salmiana stimulated the abundance and diversity of the microbiota,specifically on genera Faecalibacterium and Holdemanella,thus,leading to a healthier gut microbiota,which led to obtaining the best anthropometric changes in synbiotic groups.Synbiotic intervention may provide health benefits to children with overweight or obesity by increasing the richness of the gut microbiota and stimulate beneficial bacteria.Nevertheless,more studies are needed to get a better understanding of the mechanisms of action.
文摘This paper conveys a cross-cultural understanding of the Chinese "Belt and Road Initiative"(BRI)using principles of western rhetoric as basis for inter- pretation.Thus,an American perspective is stressed.Most specifically,Kenneth Burke's Dramatistic Pentad is used for initial clarification along with the explana- tion of how further understanding can be realized via Fantasy Theme Analysis to better appreciate the expression of rhetorical vision.Recognition of how BRI can be understood differently,depending on the cultural context,is emphasized.This is couched in the contextual framing of mass media influences as explained by Marshall McLuhan.
