RESUMO
It is often desirable to quantify a plant's relative weediness or synanthropy, that is, the degree to which a species associates with human-caused disturbance, in order to study and understand the biology, ecology and evolution of weeds and invasive plants. Herbarium specimens are among the most accessible and verifiable sources of data on distribution and habitat. However, the habitat distribution of species may not be reflected accurately by herbarium specimen data, due to well-known biases in plant collection. Here, we assess how well herbarium specimens reflect species' weediness, when compared with direct field surveys. We used five species of Melampodium (Asteraceae) and classified their degree of weediness with a modification of Nuorteva's synanthropy index, based on herbarium specimens. We then modelled the distribution of our focal species in Mexico using MaxEnt and identified a polygon of â¼3000 km(2) in the state of Nayarit, Mexico, where there was a high probability of finding all five species. Systematic field searches in the target area documented all visible populations of four species along major and minor roads. Then we, again, classified their degree of weediness with the synanthropy index, based now on field data, and compared. We found that herbarium data were an accurate predictor of a species' weediness relative to its congeners despite the well-documented skew of herbarium data towards natural areas, which our data reflected as well. So, herbarium data can be used to classify species' weediness relative to each other, but not in absolute terms, if the specimens were correctly identified and none of the species were subject to particular collection bias. This study is the first attempt to compare herbarium and field data on this subject and may be relevant for other types of investigations based on herbarium data. Our work also highlights the usefulness of distribution models based on herbarium specimens.
RESUMO
OBJECTIVES: The aim of this observational study in patients with chronic hepatitis C and treated with interferon alpha-2a was to assess 1) monitoring in everyday practice, 2) the acceptability of treatment and 3) the intensity of fatigue. METHODS: Three hundred and fifty four patients were enrolled by physicians in both teaching and general hospitals, or private practice. Before treatment, clinical, epidemiological, and virological data were collected as well as a self-evaluation of fatigue using a visual analogic scale. Clinical follow-up was assessed every 3 months during treatment and 6 months after the end of treatment and included an evaluation of fatigue and the number of workdays missed due to sickness. RESULTS: Two hundred and nineteen men and 135 women, mean age 45 +/- 13, were included. The epidemiological, histological and virological features of this group were similar to those patients usually treated for chronic hepatitis C. Before treatment, the mean measurement of fatigue was 41 on a scale from 0 (perfect form) to 100 (exhausted). Fatigue was unrelated to age, source of infection, biological activity, or histological score. It worsened in patients who stopped interferon after 3 or 6 months, but was stable in patients who continued treatment for 12 months. Fatigue decreased after the end of treatment and was unrelated to treatment response. The need to stop work was strongly related to the intensity of fatigue and the number of workdays missed due to sickness represented nearly two months out of three in 25% of active patients during the first quarter and in 15% of patients thereafter. 61% of patients self-injected interferon (mainly previous drug users) whereas 30% of patients used nurse care throughout treatment. CONCLUSION: This study not only provides a realistic evaluation of fatigue in patients with chronic hepatitis C, before, during and after treatment, but also highlights its social and economic consequences. It shows the need for further cost-effectiveness studies on new therapeutic strategies using combined treatments.
