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Severity Gradient (severity + gradient)
Selected AbstractsDebating the greening vs. browning of the North American boreal forest: differences between satellite datasetsGLOBAL CHANGE BIOLOGY, Issue 2 2010DOMINGO ALCARAZ-SEGURA Abstract A number of remote sensing studies have evaluated the temporal trends of the normalized difference vegetation index (NDVI or vegetation greenness) in the North American boreal forest during the last two decades, often getting quite different results. To examine the effect that the use of different datasets might be having on the estimated trends, we compared the temporal trends of recently burned and unburned sites of boreal forest in central Canada calculated from two datasets: the Global Inventory, Monitoring, and Modeling Studies (GIMMS), which is the most commonly used 8 km dataset, and a new 1 km dataset developed by the Canadian Centre for Remote Sensing (CCRS). We compared the NDVI trends of both datasets along a fire severity gradient in order to evaluate the variance in regeneration rates. Temporal trends were calculated using the seasonal Mann,Kendall trend test, a rank-based, nonparametric test, which is robust against seasonality, nonnormality, heteroscedasticity, missing values, and serial dependence. The results showed contrasting NDVI trends between the CCRS and the GIMMS datasets. The CCRS dataset showed NDVI increases in all recently burned sites and in 50% of the unburned sites. Surprisingly, the GIMMS dataset did not capture the NDVI recovery in most burned sites and even showed NDVI declines in some burned sites one decade after fire. Between 50% and 75% of GIMMS pixels showed NDVI decreases in the unburned forest compared with <1% of CCRS pixels. Being the most broadly used dataset for monitoring ecosystem and carbon balance changes, the bias towards negative trends in the GIMMS dataset in the North American boreal forest has broad implications for the evaluation of vegetation and carbon dynamics in this region and globally. [source] Comorbidity of depression and anxiety in nursing home patientsINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 3 2005Martin Smalbrugge Abstract Objectives To assess the occurrence and risk indicators of depression, anxiety, and comorbid anxiety and depression among nursing home patients and to determine whether depression and anxiety are best described in a dimensional or in a categorical classification system. Methods DSM and subthreshold anxiety disorders, anxiety symptoms, major and minor depression and depressive symptoms were assessed in 333 nursing home patients of somatic wards of 14 nursing homes in the north west of the Netherlands with the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and the Geriatric Depression Scale (GDS). Comorbidity was studied along a severity gradient. Logistic regression analyses were carried out to identify demographic, health-related, psychosocial and care-related correlates of anxiety and depression. Results The prevalence of pure depression (PD) was 17.1%, of pure anxiety (PA) 4.8%, and of comorbid anxiety and depression (CAD) 5.1%. Comorbidity increased dependent on severity of both anxiety and depression. Different patterns of risk indicators were demonstrated for PA, PD and CAD for the investigated baseline characteristics. Conclusions Comorbidity of anxiety and depression is most prevalent in the more severe depressive and anxious nursing home patients. The gradual increase of comorbidity of anxiety and depression dependent on the levels of severity of depression and anxiety suggests that for nursing home patients a dimensional classification of depression and anxiety is more appropriate than a categorical one. The observed differences in patterns of risk indicators for PA, PD and CAD support a distinguishing of anxiety and depression. Future studies are needed to assess the effect of treatment of PA, PD and CAD in nursing home patients. Copyright © 2005 John Wiley & Sons, Ltd. [source] Effects of fire severity in a north Patagonian subalpine forestJOURNAL OF VEGETATION SCIENCE, Issue 1 2005Thomas Kitzberger Abstract. Question: What is the relative importance of fire-induced canopy mortality, soil burning and post-fire herbivory on tree seedling performance? Location: Subalpine Nothofagus pumilio forests at Challhuaco valley (41°13'S, 71°19'W), Nahuel Huapi National Park, Argentina. Methods: We fenced and transplanted soils of three burning severities along a fire severity gradient produced by a fire in 1996. Over two growing seasons we monitored soil water, direct incoming solar radiation, seedling survival, final seedling total biomass and root/shoot ratio. Additionally, we assessed severity-related changes in soil properties. Results: Incoming radiation (an indicator of the amount of canopy cover left by the fire) was the primary factor influencing spring and summer top soil water availability, first and second-year seedling survival and seedling growth. While seedling survival and soil water content were negatively affected by increased radiation, seedling final biomass was highest in very open microsites. Burned soils showed lower water holding capacity and soil carbon; however these changes did not affect topsoil water, and, contrary to expectation, there was a slight tendency toward higher seedling survival on more heavily burned soils. Herbivory significantly reduced seedling survival, but only under high-radiation conditions. While the effect of radiation on final seedling biomass was not affected by herbivory, R/S ratios were significantly reduced by herbivory in high radiation micro sites. Conclusions: Despite inducing faster aerial growth, increased radiation and herbivory in severely burned sites may effectively prevent post-fire regeneration in north Patagonian subalpine forest where seed sources are not limiting. [source] Validity of the Spanish version of the Chronic Liver Disease Questionnaire (CLDQ) as a standard outcome for quality of life assessment,LIVER TRANSPLANTATION, Issue 1 2006Montserrat Ferrer The Chronic Liver Disease Questionnaire (CLDQ) measures the impact on quality of life of chronic liver diseases, regardless of underlying etiology. The aim of this study was to develop a Spanish version of the CLDQ, and to assess its acceptability, reliability, validity, and sensitivity to change. The forward and back-translation method by bilingual translators, with expert panel and pilot testing on patients, was used for the adaptation. The final version was self-administered, together with the Short Form-36 Health Survey (SF-36), on 149 consecutive patients with chronic liver disease. Child-Turcotte-Pugh scores were evaluated by a physician. To assess reproducibility and responsiveness the CLDQ was readministered to a subsample of stable patients and to those who had received a liver transplant. Validity was evaluated via exploratory factor analysis, the CLDQ pattern across severity groups, and correlation coefficients with "itching" and SF-36 scores. Cronbach's alpha and Intraclass Correlation Coefficient for CLDQ global score were 0.93 and 0.90, respectively, demonstrating good reliability. Validity was supported by correlations of the CLDQ with SF-36 and "itching," and CLDQ severity gradient (global score means were 5.5, 5.2, 5.0, and 4.5 in patients with no cirrhosis, cirrhosis Child-Turcotte-Pugh A, B, and C, respectively; P = 0.012). Responsiveness was shown by a high CLDQ improvement in patients who had received liver transplant (mean change = ,1.4; P < 0.001). In conclusion, the Spanish CLDQ is reliable, valid, responsive, and equivalent to the original. These findings support its use as a standard outcome for patients with chronic liver diseases within the whole severity range, from "no cirrhosis" to transplant recipients, both in Spanish and international studies. Liver Transpl 12:95,104, 2006. © 2005 AASLD. [source] | ||||||||||