The regional ionospheric model is adopted to determine satellite-plus-receiver differential delay. The satellite-plus-receiver differential delay is estimated as constant values for each day. Dual-frequency GPS pseudo...The regional ionospheric model is adopted to determine satellite-plus-receiver differential delay. The satellite-plus-receiver differential delay is estimated as constant values for each day. Dual-frequency GPS pseudo-ranges observables are used to compute vertical TEC (VTEC). All the monthly mean VTEC profiles are represented by graphs using GPS data of the Beijing IGS site between 2000 and 2004. The monthly averaged values and amplitudes of VTEC are also represented by graphs. The results indicate that the VTEC has seasonal dependency. The monthly averaged values and amplitudes of VTEC in 2000 are about 2 times larger than that in 2004. The maximum VTEC values are observed in March and April, while the minimum VTEC values are observed in December. The seasonal variations trend is found to be similar after polynomial fitting between 2000 and 2004.展开更多
AIM: To study a cohort of patients undergoing 48 h Bravo pH testing receiving deep sedation with propofol. METHODS: We retrospectively reviewed the charts of 197 patients (81 male, 116 female) who underwent Bravo ...AIM: To study a cohort of patients undergoing 48 h Bravo pH testing receiving deep sedation with propofol. METHODS: We retrospectively reviewed the charts of 197 patients (81 male, 116 female) who underwent Bravo esophageal pH monitoring from July 2003 to January 2008. All patients underwent Bravo pH probe placement via esophagogastroduodenoscopy (EGD) and received propofol for sedation. Patients on a proton pump inhibitor (89 patients) were excluded. Acid reflux variables measured included the total, upright, and supine fractions of time at pH 〈 4 and DeMeester score, and were compared between day I and day 2. RESULTS: Of the 108 patients that were included in the study, the most common indication for Bravo pH monitoring was heartburn, with chest pain being the second most common. A signed rank test revealed no statistically significant difference between day I and day 2 reflux episodes. CONCLUSION: Patients who received propofol for sedation for EGD with Bravo pH capsule placement did not experience any significant difference in reflux episodes from day 1 to day 2.展开更多
In real-life freeway transportation system, a few number of incident observation (very rare event) is available while there are large numbers of normal condition dataset. Most of researches on freeway incident detec...In real-life freeway transportation system, a few number of incident observation (very rare event) is available while there are large numbers of normal condition dataset. Most of researches on freeway incident detection have considered the incident detection problem as classification one. However, because of insufficiency of incident events, most of previous researches have utilized simulated incident events to develop freeway incident detection models. In order to overcome this drawback, this paper proposes a wavelet-based Hotelling 7a control chart for freeway incident detection, which integrates a wavelet transform into an abnormal detection method. Firstly, wavelet transform extracts useful features from noisy original traffic observations, leading to reduce the dimensionality of input vectors. Then, a Hotelling T2 control chart describes a decision boundary with only normal traffic observations with the selected features in the wavelet domain. Unlike the existing incident detection algorithms, which require lots of incident observations to construct incident detection models, the proposed approach can decide a decision boundary given only normal training observations. The proposed method is evaluated in comparison with California algorithm, Minnesota algorithm and conventional neural networks. The experimental results present that the proposed algorithm in this paper is a promising alternative for freeway automatic incident detections.展开更多
Since 2003, the sites of the national environmental monitoring system (DNSE) of Niger, set up by the long term ecological monitoring observatories network (ROSELT) with the support of the Sahel and Sahara Observat...Since 2003, the sites of the national environmental monitoring system (DNSE) of Niger, set up by the long term ecological monitoring observatories network (ROSELT) with the support of the Sahel and Sahara Observatory (OSS), were used to collect ecological data with harmonized methods for spatio-temporal comparisons purpose. Floristic and phytoecological data were collected using the phytosociological methodology of Braun-Blanquet (1932). Ecosystem vital attributes used included the specific diversity, alpha diversity, equidistribution, biological types and herbaceous phytomass. At the whole system scale, the analysis revealed that the specific diversity, the alpha diversity and the phytomass values were higher in less disturbed biotopes of the north soudanian and south sahelian bioclimates where the rainfall rate is relatively high. Regarding the north sahelian and saharian bioclimates, the topography may play a critical role in the redistribution of this phytodiversity. Besides, the distribution of the biological types showed the prevalence of therophytes (56.8 ± 11%) regardless of the bioclimate and, to a lesser extent, the perennial species (26.5 ± 7.3%), the later group showing higher values for the north soudanian bioclimate.展开更多
Spatial pattern and interdependence of different soil and plant parameters were examined in green bean field experiment carried out at the Mediterranean Agronomic Institute of Bari (MAIB), Italy. The study aimed to ...Spatial pattern and interdependence of different soil and plant parameters were examined in green bean field experiment carried out at the Mediterranean Agronomic Institute of Bari (MAIB), Italy. The study aimed to identify the spatial distribution of soil and plant parameters and their relationship at transects scale. The experiment consisted of three transects of 30 m length and 4.2 m width, irrigated with three different salinity levels (1 dSm"1, 3 dSm1, 6 dSml). Soil measurements (electrical conductivity and soil water content) were monitored along each transect in 24 sites, using TDR probe installed vertically at soil surface. Water storage was measured by using Diviner sensor for calculating directly the evapotranspiration fluxes along the whole soil profile under the different salinity levels imposed during the experiment. In the same 24 sites, crop monitoring involved measurements of Leaf Area Index (LAI), Osmotic Potential (OP), Root length Density (RID) and Evapotranspiration fluxes (ET). Soil and plant properties were analyzed using both classical and geostatistical methods which included descriptive statistics, semivariograms and cross-semivariograms. Results indicated that moderate to large spatial variability existed across the field for soil and plant parameters, especially under the 6 dSm1 salinity treatment. A relatively satisfactory fit of the experimental cross-semivariogram was obtained for the 6 dS1, thus indicating similar spatial structures of the pairs of compared variables. By contrast, the experimental cross-semivariograms observed under the 3 dS~ treatment indicated no significant correlation structure between the compared variables. Overall, the results observed in the 3 dSm-1 were not significantly different from those obtained in the 1 dSm-1 transect and suggested a general insensitivity of the crop response to those levels of salinity.展开更多
基金Supported by the Open Research Fund Program of the Geomatics and Applications Laboratory, Liaoning Technical University (No.2005010)theScience and Technology Fund of China University of Mining and Technology(No.2005B020).
文摘The regional ionospheric model is adopted to determine satellite-plus-receiver differential delay. The satellite-plus-receiver differential delay is estimated as constant values for each day. Dual-frequency GPS pseudo-ranges observables are used to compute vertical TEC (VTEC). All the monthly mean VTEC profiles are represented by graphs using GPS data of the Beijing IGS site between 2000 and 2004. The monthly averaged values and amplitudes of VTEC are also represented by graphs. The results indicate that the VTEC has seasonal dependency. The monthly averaged values and amplitudes of VTEC in 2000 are about 2 times larger than that in 2004. The maximum VTEC values are observed in March and April, while the minimum VTEC values are observed in December. The seasonal variations trend is found to be similar after polynomial fitting between 2000 and 2004.
文摘AIM: To study a cohort of patients undergoing 48 h Bravo pH testing receiving deep sedation with propofol. METHODS: We retrospectively reviewed the charts of 197 patients (81 male, 116 female) who underwent Bravo esophageal pH monitoring from July 2003 to January 2008. All patients underwent Bravo pH probe placement via esophagogastroduodenoscopy (EGD) and received propofol for sedation. Patients on a proton pump inhibitor (89 patients) were excluded. Acid reflux variables measured included the total, upright, and supine fractions of time at pH 〈 4 and DeMeester score, and were compared between day I and day 2. RESULTS: Of the 108 patients that were included in the study, the most common indication for Bravo pH monitoring was heartburn, with chest pain being the second most common. A signed rank test revealed no statistically significant difference between day I and day 2 reflux episodes. CONCLUSION: Patients who received propofol for sedation for EGD with Bravo pH capsule placement did not experience any significant difference in reflux episodes from day 1 to day 2.
文摘In real-life freeway transportation system, a few number of incident observation (very rare event) is available while there are large numbers of normal condition dataset. Most of researches on freeway incident detection have considered the incident detection problem as classification one. However, because of insufficiency of incident events, most of previous researches have utilized simulated incident events to develop freeway incident detection models. In order to overcome this drawback, this paper proposes a wavelet-based Hotelling 7a control chart for freeway incident detection, which integrates a wavelet transform into an abnormal detection method. Firstly, wavelet transform extracts useful features from noisy original traffic observations, leading to reduce the dimensionality of input vectors. Then, a Hotelling T2 control chart describes a decision boundary with only normal traffic observations with the selected features in the wavelet domain. Unlike the existing incident detection algorithms, which require lots of incident observations to construct incident detection models, the proposed approach can decide a decision boundary given only normal training observations. The proposed method is evaluated in comparison with California algorithm, Minnesota algorithm and conventional neural networks. The experimental results present that the proposed algorithm in this paper is a promising alternative for freeway automatic incident detections.
文摘Since 2003, the sites of the national environmental monitoring system (DNSE) of Niger, set up by the long term ecological monitoring observatories network (ROSELT) with the support of the Sahel and Sahara Observatory (OSS), were used to collect ecological data with harmonized methods for spatio-temporal comparisons purpose. Floristic and phytoecological data were collected using the phytosociological methodology of Braun-Blanquet (1932). Ecosystem vital attributes used included the specific diversity, alpha diversity, equidistribution, biological types and herbaceous phytomass. At the whole system scale, the analysis revealed that the specific diversity, the alpha diversity and the phytomass values were higher in less disturbed biotopes of the north soudanian and south sahelian bioclimates where the rainfall rate is relatively high. Regarding the north sahelian and saharian bioclimates, the topography may play a critical role in the redistribution of this phytodiversity. Besides, the distribution of the biological types showed the prevalence of therophytes (56.8 ± 11%) regardless of the bioclimate and, to a lesser extent, the perennial species (26.5 ± 7.3%), the later group showing higher values for the north soudanian bioclimate.
文摘Spatial pattern and interdependence of different soil and plant parameters were examined in green bean field experiment carried out at the Mediterranean Agronomic Institute of Bari (MAIB), Italy. The study aimed to identify the spatial distribution of soil and plant parameters and their relationship at transects scale. The experiment consisted of three transects of 30 m length and 4.2 m width, irrigated with three different salinity levels (1 dSm"1, 3 dSm1, 6 dSml). Soil measurements (electrical conductivity and soil water content) were monitored along each transect in 24 sites, using TDR probe installed vertically at soil surface. Water storage was measured by using Diviner sensor for calculating directly the evapotranspiration fluxes along the whole soil profile under the different salinity levels imposed during the experiment. In the same 24 sites, crop monitoring involved measurements of Leaf Area Index (LAI), Osmotic Potential (OP), Root length Density (RID) and Evapotranspiration fluxes (ET). Soil and plant properties were analyzed using both classical and geostatistical methods which included descriptive statistics, semivariograms and cross-semivariograms. Results indicated that moderate to large spatial variability existed across the field for soil and plant parameters, especially under the 6 dSm1 salinity treatment. A relatively satisfactory fit of the experimental cross-semivariogram was obtained for the 6 dS1, thus indicating similar spatial structures of the pairs of compared variables. By contrast, the experimental cross-semivariograms observed under the 3 dS~ treatment indicated no significant correlation structure between the compared variables. Overall, the results observed in the 3 dSm-1 were not significantly different from those obtained in the 1 dSm-1 transect and suggested a general insensitivity of the crop response to those levels of salinity.