Meltwater temperature in streams draining Alpine glaciers.

Climate change is significantly impacting lotic environments, through changes to hydrology, biodiversity and species distribution. Effects of climate change are greatest at high elevation and biota in and around glacier-fed rivers is likely, therefore, to be at great risk. How climate change influences hydrology will have great impact on river water temperature as glacier-fed rivers in Alpine environments are extremely sensitive to climatic change. This paper assesses five rivers: Four glacier-fed rivers (36.9-83.7% basin glacierisation) located in the Swiss Alps, and one located in an ice-free catchment in the Bernese Oberland, Switzerland. The aim was to assess the impact of basin characteristics on river water temperature. A distinct paradoxical relationship was identified whereby water temperature in some glacier-fed rivers was reduced during the time of highest incoming shortwave radiation receipts and high air temperature. Whether a summer cooling effect presented itself in all glacier-fed rivers within this study was researched. The key findings were that the identified summer cooling effect was not present in all rivers, despite percentage glacierisation. Percentage glacier cover has often been reported as they key determiner of water temperature in such rivers. More important was the stream dimensions, notably stream surface area. Understanding the controlling factors that influence water temperature of glacier-fed rivers will help river managers and planners in understanding how climate change will affect fisheries downstream of glaciers over the coming decades. This may allow plans to be introduced to try and mitigate warmer water temperature that will result, in some glacier-fed rivers, as the climate warms.

Measuring depression: comparison and integration of three scales in the GENDEP study.

BACKGROUND: A number of scales are used to estimate the severity of depression. However, differences between self-report and clinician rating, multi-dimensionality and different weighting of individual symptoms in summed scores may affect the validity of measurement. In this study we examined and integrated the psychometric properties of three commonly used rating scales. METHOD: The 17-item Hamilton Depression Rating Scale (HAMD-17), the Montgomery-Asberg Depression Rating Scale (MADRS) and the Beck Depression Inventory (BDI) were administered to 660 adult patients with unipolar depression in a multi-centre pharmacogenetic study. Item response theory (IRT) and factor analysis were used to evaluate their psychometric properties and estimate true depression severity, as well as to group items and derive factor scores. RESULTS: The MADRS and the BDI provide internally consistent but mutually distinct estimates of depression severity. The HAMD-17 is not internally consistent and contains several items less suitable for out-patients. Factor analyses indicated a dominant depression factor. A model comprising three dimensions, namely 'observed mood and anxiety', 'cognitive' and 'neurovegetative', provided a more detailed description of depression severity. CONCLUSIONS: The MADRS and the BDI can be recommended as complementary measures of depression severity. The three factor scores are proposed for external validation.

Extraction procedures for atomic absorption spectrometric analysis of toxic metals in urban dust.

A comparison has been made of eight acid extraction systems prior to the atomic absorption analysis of lead, nickel, copper, cadmium, cobalt, chromium, zinc, arsenic and mercury in street dust samples. Statistical treatment of the results enabled a valid comparison to be made in terms of overall extraction efficiency. For the purposes of carrying out large scale environmental surveys it was found that extraction with dilute nitric acid was the most suitable method. Analysis of the extracts by atomic absorption spectroscopy was shown to permit the accumulation of reliable data with the minimum requirement of apparatus and time.

The influence of local tissue environment on epithelial basement membrane continuity in colorectal carcinomas.

For colorectal carcinomas, there is evidence that marked discontinuity of the epithelial basement membrane (EBM) is associated with higher malignant potential. Since the metastatic process appears to be selective, more discontinuous EBMs might be expected in secondary rather than in primary tumours. To test this prediction, we examined a series of 60 cases of colorectal carcinoma for which samples of lymph-node or liver metastases were available. Sections were immunocytochemically stained for laminin, and the continuity of tumour EBM was then assessed by observational rating as well as by detailed morphometric analysis for a sample of cases. Contrary to the above prediction, we find that EBMs tend to be more continuous in secondary tumours than in corresponding primary tumours. These results could be explained by the possibility that local tissue environmental factors have a major influence on EBM continuity. Supporting evidence comes from our previous observation that EBM is very discontinuous at the advancing edge of primary colorectal carcinomas, where the tumour is adjacent to collagen-I-deficient stroma. Further evidence from the present study is that the EBM is extremely discontinuous at the interface between metastases and specialised parechymal tissue, but more continuous at the interface between metastases and stromal connective tissue. Since basement membranes affect the differentiation and behaviour of adjacent cells, these findings suggest that host tissue may influence invasive activity through their effects on EBM continuity.