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Localized ecological systems are known to shift abruptly and irreversibly from one state to another when they are forced across critical thresholds. Here we review evidence that the global ecosystem as a whole can react in the same way and is approaching a planetary-scale critical transition as a result of human influence. The plausibility of a(More)
BACKGROUND Previous research on educational data has demonstrated that Rasch fit statistics (mean squares and t-statistics) are highly susceptible to sample size variation for dichotomously scored rating data, although little is known about this relationship for polytomous data. These statistics help inform researchers about how well items fit to a(More)
The Hospital Anxiety and Depression Scale (HADS) is widely used as a tool for assessing psychological distress in patients and non-clinical groups. Previous studies have demonstrated conflicting results regarding the factor structure of the questionnaire for different groups of patients, and the general population. This study investigated the factor(More)
This paper focuses on the U.S. Billion-dollar Weather/Climate Disaster report by the National Oceanic and Atmospheric Administration's National Climatic Data Center. The current methodology for the production of this loss dataset is described, highlighting its strengths and limitations including sources of uncertainty and bias. Department of Agriculture's(More)
BACKGROUND Although the Functional Assessment of Cancer Therapy--General questionnaire (FACT-G) has been validated few studies have explored the factor structure of the instrument, in particular using non-sample dependent measurement techniques, such as Rasch Models. Furthermore, few studies have explored the relationship between item fit to the Rasch Model(More)
Phenotypic traits mediate organisms' interactions with the environment and determine how they affect and are affected by their biotic and abiotic milieu. Thus, dispersion of trait values, or functional diversity (FD) of a community can offer insights into processes driving community assembly. For example, underdispersion of FD suggests that habitat(More)
Host population thresholds for the invasion or persistence of infectious disease are core concepts of disease ecology and underlie disease control policies based on culling and vaccination. However, empirical evidence for these thresholds in wildlife populations has been sparse, although recent studies have begun to address this gap. Here, we review the(More)
OBJECTIVE To validate an item bank for assessing and detecting psychological distress in cancer patients by (1) identifying whether additional items are required in the full item bank; (2) identifying any item bias in the existing item bank; (3) linking levels of distress against thresholds derived from gold-standard psychiatric interviews (PSE/SCAN/SCID).(More)
The aim of the study was to confirm the validity of using touchscreen computers for screening for clinically significant levels of distress among cancer patients in routine oncology practice. The Hospital Anxiety and Depression Scale (HADS), EORTC Quality of Life questionnaire (QLQ-C30), Mental Health Inventory-MHI5 and a Concerns Checklist were(More)
Psychological distress is a common problem among cancer patients. Despite the large number of instruments that have been developed to assess distress, their utility remains disappointing. This study aimed to use Rasch models to develop an item-bank which would provide the basis for better means of assessing psychological distress in cancer patients.An item(More)