Spatial variability in macroinvertebrate assemblages along and among neighbouring equatorial glacier‐fed streams

1. During the past two decades, understanding of the structure and function of glacier‐fed stream ecosystems at temperate latitudes has increased substantially. In contrast, information on their tropical counterparts is very limited. We studied three neighbouring glacier‐fed streams in the tropical Andes of Ecuador. Our main goals were (i) to determine overall longitudinal patterns in density, taxon richness and the composition of macroinvertebrate assemblages and driving factors in equatorial glacial streams and (ii) to examine variability among replicate streams in faunal metrics and assemblages, and stream‐specific effects of supposed environmental key factors. 2. We measured four geographical and 17 environmental factors and collected five Surber samples (500 cm²) of macroinvertebrates at each of nine sites, three sites along three streams. The streams were located 1–5 km apart. In each stream, the three sites were placed at comparable distances from the glacier and were grouped as ‘upper’ (50–200 m), ‘middle’ (1.5 km) and ‘lower’ sites (3.5–5.6 km). 3. In total, 2200 individuals (64% chironomids) were collected and 47 taxa (30 dipterans, 18 of these Chironomidae) identified. Density ranged from 176 to 372 ind. m^?2, and the number of taxa ranged from 2 to 6 at the upper sites and 868–3044 ind. m^?2 and 21–27 taxa at the lower sites. Density, number of taxa, rarefied richness and axis‐1 coordinates from a MDS ordination increased logarithmically with distance from the glacier. These faunal metrics were equally related to altitude and glacier per cent of catchment and correlated with maximum conductivity, mean temperature, mean daily maximum temperature and a channel stability index. As expected, the mean difference in distance decay in similarity was higher at the upper (47% km^?1) than at the lower reaches (20% km^?1) of the streams. 4. The number of taxa varied among sites within the upper and middle groups, but not among the lower sites. In contrast, but in accordance with our expectation, assemblage composition did not differ among upper sites but did so at middle and lower sites, following a supposed decrease in environmental harshness along the streams. Relationships between faunal metrics and the four environmental variables mean temperature, the stability index, chlorophyll a and coarse particulate organic matter also varied among the three streams. Generalised linear model analyses revealed that temperature interacted with stream on macroinvertebrate density, while chlorophyll a had a significant effect on the number of taxa in interaction with stream and stability. 5. The basic predictions of the Milner et al. (2001a) , model regarding longitudinal faunal patterns and temperature and stability as main driving factors were met by our three replicate equatorial glacial streams. Qualitative departures from the model were mainly because of zoogeographical differences. We demonstrated that variability in assemblages between comparable sites in closely situated streams was considerable, and the effect of key environmental factors varied among streams and interacted with other factors. Quantifying spatial variation in benthic assemblages may help us foresee possible consequences for biodiversity as a result of glacial retreat.     

Bronchoalveolar Lavage In the Diagnosis of Bronchiolo-Alveolar Carcinoma. A Case Report

Bronchiolo-alveolar carcinoma is usually localized to the terminal bronchioles and alveoli, and may present on chest X-ray as interstitial pulmonary disease with diffuse reticulonodular infiltrates. The cytological diagnosis is often difficult to obtain. This case demonstrates that bronchoalveolar lavage can be useful in the diagnostic evaluation of this type of malignancy, in conjunction with transbronchial lung biopsy.     

Estimation of plant and leaf area index using three techniques in a mature native eucalypt canopy

Abstract Leaf area index (L) is a critical variable in monitoring and modelling forest condition and growth and is therefore important for foresters and environmental scientists to measure routinely and accurately. We compared three different methods for estimating L: a plant canopy analyser (PCA), a point‐quadrat camera method and digital hemispherical photography at a native eucalypt forest canopy at Tumbarumba in southern New South Wales, Australia. All of these methods produced indirect estimates of L based on the close coupling between radiation penetration and canopy structure. The individual L estimates were compared, and the potential advantages and disadvantages of each method were discussed in relation to use in forest inventory and in field data collection programmes for remote sensing calibration and verification. The comparison indicated that all three methods, PCA, digital hemispherical photography and the modified point‐quadrat camera method, produced similar estimates with a standard error between techniques of less than 0.2 L units. All methods, however, provided biased estimates of L and calibration is required to derive true stand L. A key benefit, however, of all of these estimation methods is that observations can be collected in a short period of time (1–2 h of field‐work per plot).     

REFLECTIVE EQUILIBRIUM AND EMPIRICAL DATA: THIRD PERSON MORAL EXPERIENCES IN EMPIRICAL MEDICAL ETHICS

In ethics, the use of empirical data has become more and more popular, leading to a distinct form of applied ethics, namely empirical ethics. This ‘empirical turn’ is especially visible in bioethics. There are various ways of combining empirical research and ethical reflection. In this paper we discuss the use of empirical data in a special form of Reflective Equilibrium (RE), namely the Network Model with Third Person Moral Experiences. In this model, the empirical data consist of the moral experiences of people in a practice. Although inclusion of these moral experiences in this specific model of RE can be well defended, their use in the application of the model still raises important questions. What precisely are moral experiences? How to determine relevance of experiences, in other words: should there be a selection of the moral experiences that are eventually used in the RE? How much weight should the empirical data have in the RE? And the key question: can the use of RE by empirical ethicists really produce answers to practical moral questions? In this paper we start to answer the above questions by giving examples taken from our research project on understanding the norm of informed consent in the field of pediatric oncology. We especially emphasize that incorporation of empirical data in a network model can reduce the risk of self‐justification and bias and can increase the credibility of the RE reached.     

Endoplasmic Reticulum-dictyosome Involvement in the Origin of Refractive Spherules in Sieve Elements of Davallia fijiensis Hook

Young sieve elements from petioles and rachises of Davalliafijiensis Hook were examined with an electron microscope. Evidencewas obtained that implicated both the endoplasmic reticulum(ER) and the Golgi apparatus in the formation of refractivespherules. Numerous connections were observed between smooth,tubular ER and peripheral tubules of the dictyosomes, indicatingthat these two cytoplasmic components are parts of a singleendomembrane system. Davallia fijiensis Hook, endomembrane system, endoplasmic reticulum, dictyosome, refractive spherule, sieve element     

The Effect of Filtration On the Cellular Components In Bronchoalveolar Lavage Fluid

The effect of filtration through two layers of cotton gauze on the cellular composition of bronchoalveolar lavage (BAL) fluid was studied in 25 patients with pulmonary disease. There was no significant difference between median total cell count in unfiltered and filtered BAL (P= 0.73) or in the distribution of neutrophils or eosinophils. the percentage of bronchial epithelial cells was significantly higher in unfiltered than in filtered BAL (P= 0.02). Furthermore, differential cell counts showed a significantly lower percentage of alveolar macrophages (P= 0.04), and a significantly higher percentage of lymphocytes (P=0.04) in unfiltered compared with filtered BAL. Thus, gauze filtration results in a loss of bronchial epithelial cells and lymphocytes, and is not recommended in the routine analysis of cellular components in BAL fluid. L'effet de la filtration à travers deux couches de gaze de coton sur la composition cellulaire du liquide de lavage broncho-alvéolaire (LBA) a étéétudié chez 25 patients atteints d'une pathologie pulmonaire. Aucune différence significative entre les échantillons filtrés et non filtrés n'a été trouvée en ce qui concerne la numération cellulaire totale moyenne (P=0.73) et la distribution des polynucléaires neutrophiles et eosinophiles. Le pourcentage de cellules épithéliales bronchiques est significativement plus élevé dans les échantillons non filtrés que dans ceux qui ont été filtrés (P= 0.02). Par ailleurs, le comptage differentiel montre un pourcentage plus faible de macrophages alveolaires (P=0.04) et un pourcentage plus élevé de lymphocytes (P= 0.04) dans les LBA non filtrés. La filtration à travers la gaze a pour résultat une perte des cellules épithéliales bronchiques et des lymphocytes et n'est donc pas à recommander pour l'analyse de routine des composants cellulaires du liquide de lavage broncho-alvéolaire. Die Auswirkung einer Filtration von BAL-Material durch doppelte Baumwollgaze wurde am Material 25 Patienten untersucht. Es bestand kein signifikanter Unterschied der Zellzahl von gefiltertem und ungefiltertem Material (P= 0.73) oder im Abteil der Neutrophilen und Eosinophilen. Das Abteil des Bronchial epithelien war jedoch in ungefiltertem Material signifikant höher (P= 0.02). Differentialauszählungen zeigten einen signifikant geringeren Anteil an Alveolarmakrophagen (P= 0.04) und einen signifikant erhöhten an Lymphozyten (P= 0.04) in unfil-triertem Material. Die Filtration führt also zu einem Verlust an Bronchialepithelien und Lymphozyten und ist deshalb für Routine-untersuchungen von BAL nicht zu empfehlen.