Assessment of the relationship between thermal-infrared-based temperature−vegetation dryness index and microwave satellite-derived soil moisture

Soil moisture (SM) is an important parameter in terrestrial ecological and hydrological processes, particularly in arid and semi-arid regions. However, a highly accurate SM grid data set, which is used as a reference for the data quality, is not really suitable for the validation of other SM products. Thus, a more effective method may be necessary for evaluation of SM grid data. The temperature?vegetation dryness index (TVDI), which is estimated by the relationship between land surface temperature and vegetation index data, has been developed to assess regional water stress. Based on previous studies, we assumed a negative linear relationship between SM and the TVDI to establish the evaluation method of SM grid data. Although a highly accurate measure of SM obtained by use of microwave sensors may not always exhibit a negative linear correlation with the TVDI, the pixels of strong negative linear correlation between them signifies at least a higher accuracy of the two data at that position. The negative relationships between microwave satellite sensor-derived SM and the TVDI were tested by application of 16-day scaled satellite data in the Sahel. We determined that the correlations differ spatially according to vegetation distribution. That is, when compared with a lower correlation in the arid Sahara to the north, a higher correlation (?0.9 < r < ?0.7) was observed in the savannas, shrublands, and grasslands to the south. Our comparison results will be useful in developing validation methodologies for SM grid data in an alternative way under conditions of insufficient in situ measurements.     

Assessment of spectral indices for cover estimation of senescent vegetation

Quantification of dry plant matter (crop residue, senesced foliage, non-photosynthetic vegetation, or plant litter) surface cover (f _R) is important for assessing agricultural tillage practices, carbon sequestration, rangeland health, or brush fire hazards. The Cellulose Absorption Index (CAI) and the Shortwave Infrared Normalized Difference Residue Index (SINDRI) are two spectral indices that can remotely estimate f _R. CAI and SINDRI utilize three and two spectral bands, respectively, so SINDRI is expected to be less expensive to implement in future satellite sensors. We assessed the contrast of CAI and SINDRI with respect to soil reflectance spectra. Estimating f _R with CAI is possible for all soils. However, a number of soil samples had positive SINDRI values due to various soil minerals, such as gibbsite and antigorite, which would be interpreted as high f _R, and could limit its usefulness in some areas. Therefore, SINDRI is less applicable for estimating f _R, even with reduced implementation costs.     

Estimating fractional vegetation cover using the hand-held laser range finder: method and validation

The fractional vegetation cover is an important parameter of the earth surface system. Its ground measurement is the basis in the remotely sensed data-based vegetation inversion modelling. At present, the ground measurement methods include mainly the human ocular estimation method, the sampling method and the photographic method. However the ocular estimation method has the issue of low accuracy, and the sampling method needs to conduct some complicated operations while the photographic method is restricted by the height at which the camera can be placed. This article proposes a method using a hand-held laser range finder to make quick observation on fractional vegetation cover of low shrub vegetation. Using binomial distribution, this model established a probability distribution model about the measurement errors to calculate the fractional vegetation cover with various sampling numbers. Two experiments and one simulation using a computer were done in order to validate the method. The result shows that the fractional vegetation cover obtained by using the hand-held laser range finder can meet the precision requirements. In addition to its high precision, this method is simple in operation and calculation if compared with the traditional ground measurement methods.     

Assessing the impact of land cover map resolution and geolocation accuracy on evapotranspiration simulations by a land surface model

The land surface models used in numerical weather forecasts and hydrological applications rely on the accuracy of land cover maps available from satellite remote sensing to simulate the energy and water balance at the surface of the Earth. While the impact of classification accuracy on land surface simulations has already been reported, little attention has been paid on the consequences of land cover map uncertainty driven by geolocation accuracy. This impact on the estimated evapotranspiration (ET) from the land surface model H-TESSEL at spatial resolutions ranging from 1 to 30 km is evaluated here, making use of land cover maps at two different initial spatial resolutions, 300 and 1200 m, derived from the GlobCover global product. Geolocation uncertainty affects the land cover maps aggregated at different resolution (from 1.2 to 30 km). However, the effect decreases towards the coarsest resolutions. In addition, aggregated land cover maps are less affected by geolocation errors when the finest original resolution (300 m) is used. The maximum possible effect on ET is quantified over a heterogeneous/transition area in Europe. The result shows an impact up to 10% at 1.2-km resolution to less than 1% at 10-km resolution, at daily timescale, stressing the importance of such issues for kilometre scale applications of land surface models. The use of the highest initial land cover resolution (300 m) reduces by a factor 3 the impact of geolocation on estimated ET at 1.2- to 3-km scale. This study, therefore, stresses on the importance of a careful choice of the land cover map before carrying on land surface model simulations at the kilometre scale.     

Using GIMMS NDVI time series to estimate the impacts of grassland vegetation cover on surface air temperatures in the temperate grassland region of China

Exploring the impacts of vegetation cover on regional climate is very important to assess the relationship between vegetation and climate, and to predict regional climate change in vegetated areas. Using the time series of Global Inventory Modelling and Mapping Studies (GIMMS) normalized difference vegetation index (NDVI), we estimated the impacts of grassland vegetation cover on surface air temperatures based on the observation minus reanalysis (OMR) approach. The theory of the OMR approach is that reanalysis data are not sensitive to local land surface properties, thus the changes in OMR can be attributed to land effects. The method used in this letter is that rates of change in OMR are regressed (using stepwise regression) on average NDVI and the rate of NDVI change. We applied this multiple stepwise regression analysis in the temperate grassland region of China during the growing season from 1982 to 2005. To evaluate the accuracy of regress equations, we estimated the monthly OMR temperatures during 1983–2005 and then compared the monthly estimated and actual OMR temperatures. The results showed that the estimated OMR temperatures were well consistent with actual OMR temperatures in all the months, with the correlation coefficients between them ranging from 0.83 to 0.98. It indicates that combined with the OMR approach, GIMMS NDVI can be used to accurately estimate the impacts of grassland vegetation on surface air temperatures in temperate grassland areas of China.     

出生时间与脑卒中发病的关系

目的:研究出生时间与脑卒中的发病频数、发病年龄、性别、脑卒中病变性质(缺血性、出血性)、脑卒中病灶侧别(左、右侧脑半球)以及与脑卒中死亡的关系。方法:832例首次发病的脑卒中患者为脑卒中组。832例无脑卒中病史和脑卒中征象,按1∶1比例与脑卒中组配对性别和出生年份相同而年龄相近者为对照组。采用太阳历和干支历记录研究对象的出生时间。采用圆形分布法等,统计分析各出生时间序列与卒中发病频数、发病年龄、性别、脑卒中病变性质、脑卒中病灶侧别以及与脑卒中死亡的关系。结果:在出生12个月份上脑卒中的频数分布有集中趋势(r=0.1195,P<0.001),脑卒中组832例中出生于冬季风季节(11月～第2年4月)者476例,对照组832例中出生于冬季风季节者417例,季节性分布两组比较差异有显著性意义(P<0.005)。脑卒中的发病年龄有以4个出生月份为周期的4月节律,4月周期中年龄均数高峰值与低谷值比较差异有显著性意义(P<0.001),高峰值、低谷值分别与对照组比较差异均有显著性意义(P<0.05)。在出生10日十天干周期上,男、女脑卒中的分布均有集中趋势(P<0.001),男、女间比较差异有显著性意义(P<0.005),男、女分别与对照组比较差异均有显著性意义(P<0.05)。在出生60甲子日周期上,缺血性、出血性脑卒中的分布均有集中趋势(P     

The interacting effects of image acquisition date,number of images,classifier, and number of training samples on accuracy of binary classification of impervious cover

Selecting an appropriate time to acquire imagery for land-cover classification can have a substantial effect on classification accuracy. In this research, multi-temporal analysis of six Landsat images for binary impervious surface classification was conducted to investigate whether specific image dates (beyond simply leaf on/off) have a significant effect on impervious surface classification. We further examined the image date effects across training data sample sizes and classification algorithms. In terms of single time classification, the selection of an appropriate image time had the largest effect on the accuracy with a range of 7% to 10% between the most and least accurate classifications. The greenness transitional time between leaf off and leaf on (May images for our site) offered the highest performance. With multi-temporal images, an additional improvement in classification accuracy, up to 2.4%, was achieved when compared to the best single-time classification, when an advanced classifier (Support Vector Machine) was used. In addition, using all six available images with a reference data sample size as small as 150 pixels, classification accuracy was higher than that of many single-time classifications with substantially larger calibration data sample size. Our study suggests that there is considerable variability in classification accuracy of multi-temporal imagery and image dates should be carefully considered, beyond a general leaf on/off rule. Further testing should be conducted in other sites to identify optimal image dates.     

Blackpool sees the start of a revolution

An acute trust in Blackpool has embarked on a major project to examine every aspect of the patient experience, from the quality of nursng care to how easily patients can find their way around the hospital. Clinical staff and managers hope to make a big difference by getting 'many little things' right. This means understanding the emotional 'crunch points' that matter to patients.     

Comparison of spatial patterns of satellite-derived and ground-based phenology for the deciduous broadleaf forest of China

Using spatial phenology model-based Ulmus pumila leaf unfolding and leaf fall data at 8 km?×?8 km grids, we analysed spatial relationships between ground-based and satellite-derived growing season beginning and end dates during the period 2001–2005 and examined climatic controls on spatial correlations between ground-based and satellite-derived growing seasons. The results show that the regional mean satellite-derived growing season clearly started earlier and terminated slightly later than the regional mean ground-based growing season. Meanwhile, spatial patterns of satellite-derived growing season beginning and end dates correlate positively with spatial patterns of ground-based growing season beginning and end dates in each year (p < 0.001). Interannual variation in the difference of the slope of the spatial regression between ground-based/satellite-derived growing season beginning date and February–April temperature controls interannual variation of the spatial correlation coefficient between ground-based and satellite-derived growing season beginning date. In contrast, interannual variation of the spatial correlation coefficient between ground-based and satellite-derived growing season end date is not associated with interannual variation in the difference of the slope of the spatial regression between ground-based/satellite-derived growing season end date and September–November temperature.     

Validation of Global LAnd Surface Satellite (GLASS) fractional vegetation cover product from MODIS data in an agricultural region

Fractional vegetation cover (FVC) is an important parameter for describing the land surface vegetation conditions and widely used for land surface process simulations and global change studies. Global FVC products are mainly derived from satellite data and several global FVC products have been generated. Validation of the satellite FVC products is important before they can be applied. The objective of this study is to validate the newly generated Global LAnd Surface Satellite (GLASS) FVC product based on the time series of field FVC measurements in an agriculture region in the Heihe Basin of Northwest China. The high spatial resolution remotely sensed Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Compact Airborne Imaging Spectrometer (CASI) data were used to upscale the ground FVC measurements to validate the GLASS FVC product at 0.5 km spatial resolution. The results indicated that the GLASS FVC was highly accurate with the coefficient of determination (R²) of 0.86 and root-mean-square error (RMSE) of 0.087. Furthermore, the time series FVC profiles were consistent with the crop growing characteristics. It can be a reliable FVC product for agricultural applications.     

Validation of satellite-derived tropical cyclone heat potential with in situ observations in the North Indian Ocean

Tropical cyclone heat potential (TCHP) is an important ocean parameter influencing cyclones and hurricanes. The best approach for computing TCHP is to use in situ measurements. However, since in situ data have both spatial and temporal limitations, there is a need for satellite-based estimations. One potential solution is to use sea surface height anomalies (SSHAs) from altimeter observations. However, any estimation derived from satellite measurements requires extensive regional validation. In this letter, we compare satellite-derived TCHP values with those estimated using in situ measurements of the North Indian Ocean collected during 1993–2009. All the available measurements collected from the conductivity temperature and depth (CTD) profiler, expendable CTD profiler (XCTD), bathythermograph (BT), expendable BT (XBT) and Argo floats were used to estimate in situ derived TCHP values. TCHP estimations from satellite observations and in situ measurements are well correlated, with coefficient of determination R ² of 0.65 (0.76) and a scatter index (SI) of 0.33 (0.25) on a daily (monthly) basis for the North Indian Ocean.     

Wingate试验初始负荷比较分析

目的应用Wingate无氧试验评价无氧能力,探讨改进起始负荷方法,使该法更趋合理。方法青年运动员91名采用顺序交叉方法分别完成经典Wingate试验(TestW1)和改进的Wingate试验(TestW2),两次实验相隔24h左右,分别在Monark834E功率车上交义完成两次比较试验。结果在HRmax和LA不增加的条件下,TestW2的PP,AP明显增高,Pd明显降低(r=0.58～0.93,P<0.01),两次实验间呈高度相关(r=0.83～0.96);增加了起始加速功指标,更符合速度性项群的要求。结论TestW2更符合实验方法的近似原则,有利于发挥受试者的最大无氧能力和运动肌功率输出效率,并可改善实验方法的可重复性,更适合于速度类项群的功能评定。     

Assessing the impact of health policies on COPD

COPD is a leading but under-recognized cause of morbidity and mortality worldwide. It is currently the fourth leading cause of death in the world, and the fifth commonest cause of death in England and Wales, accounting for nearly 28,000 deaths each year. Methods: the author analyses systematically the national policies around chronic obstructive pulmonary disease such as the long term smoking cessation and NICE and BTS recommendations on COPD. Finding/conclusion: the analysis of current national policies on chronic obstructive pulmonary disease leads to a discussion to justify the need for a National Service Framework on this chronic disease. The current and future impact on local implementation is also analysed.     

Assessing the effects of drugs on choice performance

Interest in how teaching interventions and drugs jointly affect performance has produced a demand for assessment methods that are sensitive to both types of variables. An adequate assessment procedure needs to provide quantitative measures of the influence of these variables on critical aspects of performance. Two critical aspects of performance that might be adversely affected by drugs are motivation to work and ability to perform efficiently. It is shown that a work allocation model of choice, developed to examine performance maintained by reinforcers, can be used to examine the influence of varying doses of drugs on performance. When choice performance is analyzed using the work allocation model, efficiency of allocating responses can be separated from total output of responses. One data set is analyzed, where it is found that increasing doses of two stimulant drugs have different effects on performance.     

Assessing the impact on nursing practice of CDMS

Summary Two perspectives for assessing the impact of clinical data management systems on nursing are suggested. The microscopic view is the unit-level, direct patient care perspective. A macroscopic view entails consideration of national nursing issues. Nursing role issues can arise during system selection and implementation and these issues can affect system effectiveness. Professional issues influence the decisions made about CDMS and subsequent system usefulness to nursing.A shift in evaluation emphasis from time savings to assessment of effect is necessary. Suggested nursing areas to be examined are system impact on the development and use of nursing theory in practice, support for the cognitive work of nursing, and changes in the physical work of nursing.     

Assessing the impact of reengineering on nursing.

OBJECTIVES: This study assessed the impact of organizational re-engineering on nursing in a large community teaching hospital in the Midwest, using an observational repeated measures design. Time, clinical unit, and nurse characteristics were incorporated as covariates. A second objective was to compare two sampling approaches for robustness and efficiency. BACKGROUND: Economic and technological changes are having an enormous impact on acute care hospitals, which often attempt to adapt by re-engineering or restructuring their systems. Despite the difficulty of conducting research in a constantly changing setting, it is imperative that nursing evaluate its reactions and contributions to new delivery models. METHODS AND SUBJECTS: During a hospital-wide reorganization, mail surveys were conducted to assess nurses' perceptions of their authority and autonomy in a new nursing model, commitment to a new philosophy (patient-focused care), and satisfaction with their ability to deliver care. To validate the findings, patient satisfaction was evaluated through a survey of 227 hospitalized patients. Over a 1-year period, two sampling approaches were used: three independent samples of nurses were surveyed at three dates, and a panel of nurses were surveyed repeatedly over the same three dates. Response rates were approximately 45% across the independent samples and 67% for the panel. RESULTS: Comparison of nursing units that underwent re-engineering and units in which re-engineering was delayed showed no obvious effects. Data also showed that the estimates of effects of re-engineering were not subject to confounding from nursing unit, date, or nurses' experience, although there was evidence that the measures were sensitive to these covariates. No biases were found due to the two sampling schemes, yet the panel data was three to five times more efficient--that is, they produced more information--than the data from the independent samples. CONCLUSIONS: This study reinforces the need to build evaluation research into organizational activities such as re-engineering. It also argues for the commitment of resources to organizational research so that information valuable to nursing and the healthcare system is not lost.