bluuebunny/crossref_metadata_2025 huggingface dataset:
Myosin light chain kinase inhibitors and calmodulin antagonists inhibit Ca2+– and ATP–dependent catecholamine secretion from bovine adrenal chromaffin cells
Authors: Matsumura C. , Kuwashima H. , Kimura T.
Published: March 2003

1 We have used stage‐specific assays for ATP‐dependent priming and for Ca2+‐activated triggering in the absence of ATP to examine the effects of myosin light chain kinase (MLCK) inhibitors, ML‐9 and ML‐7, and calmodulin antagonists, W‐7 and trifluoperazine (TFP), on regulated exocytosis in β‐escin‐permeabilized bovine adrenal chromaffin cells.

2 Ca2+ (0.1–30 μm) induced a significantly greater secretion of catecholamines in the presence of MgATP (2 m
m) than in the absence of MgATP.

3 ML‐9 (30 and 100 μm), ML‐7 (30 and 100 μm), W‐7 (30 and 100 μm) and TFP (10 and 30 μm) inhibited the Ca2+‐induced catecholamine secretion in the presence of MgATP, but did not affect the catecholamine response to Ca2+ in the absence of MgATP.

4 In intact cells all these compounds inhibited catecholamine secretion in responses to acetylcholine (100 μm) and high K+ (40 m
m).

5 The results obtained in permeabilized cells suggest that the calmodulin‐MLCK system plays an essential role in the ATP‐requiring priming stage but not in the Ca2+‐triggered fusion step in the exocytotic process in bovine adrenal chromaffin cells.
Adrenergic–purinergic interactions on vasoconstrictor responses to periarterial electric nerve stimulation in canine splenic arteries
Authors: Yang X. ‐P. , Chiba S.
Published: March 2003

1 Periarterial nerve electrical stimulation caused a double peaked vasoconstriction in isolated perfused canine splenic arterial preparations. At low frequencies (1–3 Hz), the 1st peak responses were significantly inhibited by α,β‐methylene ATP. On the other hand, at high frequencies (8–10 Hz), the responses were not completely inhibited by α,β‐methylene ATP but the remaining response was abolished by an additional treatment of prazosin.

2 Concerning the 2nd peak responses, at low frequencies (1–3 Hz), the response was mostly suppressed by α,β‐methylene ATP, but at high frequencies (6–10 Hz), the response was not significantly modified by it, although the remaining responses were completely blocked by prazosin. Thus, at high frequencies an adrenergic and purinergic interaction may exist presynaptically, to prevent the inhibition by α,β‐methylene ATP.

3 At 1 Hz, rauwolscine, an α2‐adrenoceptor antagonist, caused a potentiation of electrical stimulation‐induced responses (both 1st and 2nd peaked responses) which were inhibited by prazosin, and the remaining ones were abolished by α,β‐methylene ATP. On the other hand, at 10 Hz, rauwolscine did not cause any potentiation of the double peaked responses.

4 The biphasic responses at 1 Hz were strongly inhibited by exogenously applied ATP, and its inhibition was reversed in part by a P1 receptor antagonist 8‐phenyltheophylline (8‐PT). On the other hand, the biphasic vasoconstrictions at 10 Hz were only slightly depressed by ATP, and a subsequent administration of 8‐PT produced a partial recovery of the 1st phase response but not that of the 2nd one.

5 From these results, it is concluded that (1) at low frequencies the double peaked responses are mostly mediated via P2X receptor, presynaptic P1 receptors may also modulate the release of ATP, and presynaptic α2‐adrenergic mechanism may tonically participate in the release of noradrenaline (2) at high frequencies the responses are mostly mediated via α1‐adrenoceptors and presynaptic P2 receptors may exert its action to inhibit the release of noradrenaline from adrenergic nerve terminals.
Probing the selectivity of allosteric modulators of muscarinic receptors at other G‐protein‐coupled receptors
Authors: Pfaffendorf M. , Batink H. D. , Tränkle C. , Mohr K. , Van Zwieten P. A.
Published: March 2003

1 The aim of the present investigation was to analyse whether three prototype allosteric modulators of ligand binding to muscarinic receptors, i.e. alcuronium, gallamine, and the alkane‐bis‐ammonium compound W84 (hexane‐1,6‐bis[dimethyl‐3′‐phthalimidopropyl‐ammonium bromide]), may have allosteric effects on radioligand‐binding characteristics at other G‐protein‐coupled receptors, such as cerebral A1 adenosine receptors (Gi‐coupled), cardiac left ventricular α1‐adrenoceptors (Gq), and β‐adrenoceptors (Gs).  2 The modulators were applied at concentrations known to be high with regard to the allosteric delay of the dissociation of the antagonist [3H]‐N‐methylscopolamine (NMS) from muscarinic M2‐receptors: 30 μmol l−1 W84, 30 μmol l−1 alcuronium, 1000 μmol l−1 gallamine. As radioligands, we used the adenosine A1‐receptor ligand [3H]‐cyclopentyl‐dipropylxanthine (CPX), the α1‐adrenoceptor ligand [3H]‐prazosin (PRAZ), and the β‐adrenoceptor ligand (−)‐[125I]‐iodocyanopindolol (ICYP). Allosteric actions on ligand dissociation and the equilibrium binding were measured in the membrane fractions of rat whole forebrain (CPX) and of rat cardiac left ventricle (PRAZ, ICYP, NMS), respectively.  3 CPX and PRAZ showed a monophasic dissociation with half‐lives of 5.88±0.15 and 12.27±0.46 min, respectively. In the case of CPX, neither the binding at equilibrium nor the dissociation characteristics were influenced by the allosteric agents. With PRAZ, the binding at equilibrium remained almost unaltered in the presence of W84, whereas it was reduced to 36±2% of the control value with alcuronium and to 42±2% with gallamine. The dissociation of PRAZ was not affected by W84, whereas it was moderately accelerated by alcuronium and gallamine. In the case of ICYP, the binding at equilibrium was not affected by the allosteric modulators. The dissociation of ICYP was slow, and after 3 h, more than 50% of the radioligand was still bound, so that a reliable half‐life could not be calculated. ICYP dissociation was not affected by W84. In the presence of alcuronium and gallamine, the dissociation curve of ICYP revealed an initial drop from the starting level, followed by the major phase of dissociation being parallel to the control curve.  4 In summary, the allosteric action of the applied agents is not a common feature of G‐protein‐coupled receptors and appears to be specific for muscarinic receptors.
Inhibition of isolated rat and human detrusor muscle contraction by disopyramide
Authors: Elliott R. A. , Hudman D. , Terry T. , Sandhu D. , Norman R. I.
Published: March 2003

1 The aim of this study was to investigate the effect of in vitro and in vivo disopyramide treatment on human and rat isolated detrusor muscle contractile response. Muscle strips were suspended in an organ bath chamber containing Kreb’s solution at 37 °C aerated with 95% oxygen and 5% carbon dioxide.

2 Disopyramide antagonized significantly the contractile response of isolated human detrusor muscle to carbachol stimulation, shifting the concentration–response curve to the right in a parallel manner. The pA2 for competitive inhibition was estimated to be 6.4 with a slope of 0.64 for disopyramide.

3 Rat detrusor muscle contractile response to electrical field stimulation (EFS) was inhibited by 28% (P < 0.01) after in vitro administration of disopyramide (7.5 × 10−6 M). Disopyramide had no effect on the atropine‐resistant component of the response to EFS or on spontaneous contractions of isolated rat detrusor muscle strips. The concentration–response curve to carbachol was competitively antagonized by disopyramide with a pA2 of 6.3 and a Schild curve a slope of 0.85.

4 Disopyramide (7.5 × 10−6 M) had no effect on rat detrusor contractile response to low concentrations of KCl but at high concentrations contraction was reduced significantly by 16% (P < 0.01).

5 In vivo treatment of rats with disopyramide for 8 days or with a single dose had a significant inhibitory effect on the contractile response of detrusor muscle strips.

6 In conclusion, disopyramide had a significant anticholinergic effect on isolated human and rat detrusor muscle contraction.
The relative importance of the time‐course of receptor occupancy and response decay on apparent antagonist potency in dynamic assays
Authors: Corsi M. , Kenakin T.
Published: March 2003

1 The potency of the β1‐adrenoceptor antagonist atenolol was measured as an inhibitor of responses to isoprenaline in guinea‐pig left atria. Measurements were made in two ways, firstly, by pre‐incubating the atria with a given concentration of atenolol followed by an isoprenaline dose–response curve and, secondly, by measuring the response to isoprenaline followed by addition of atenolol.

2 It was found that the estimation of atenolol potency as an antagonist of β1‐adrenoceptors by these two methods gave divergent results. Specifically, it was found that the isoprenaline‐induced increased rate of myocardial relaxation was resistant to receptor blockade. Thus, the rate‐limiting step in the relaxation response was dissociated from receptor activation and therefore, could not be used for the measurement of receptor occupancy.

3 In contrast, the positive inotropic response was very responsive to receptor occupancy. However, when atenolol was used to block a steady‐state isoprenaline response, there was a complicating depression of basal inotropy after receptor blockade that obfuscated measurement of receptor blockade.

4 In general, these data indicated that the blockade of a steady‐state agonist response to measure the potency of an antagonist might in some cases yield erroneous results. These studies indicate some caution in the interpretation of blockade responses in pre‐contracted or pre‐stimulated pharmacological preparations.
Numerical analyses of distributions of Iberian and Balearic endemic monocotyledons
Authors: Moreno Saiz J. C. , Castro Parga I , Sainz Ollero H
Published: March 2003

Chorological information concerning 182 taxa of monocotyledons endemic to the Iberian Peninsula and Balearic Islands was compiled and related to the 100×100 km, 50×50 km and 10×10 km UTM grids. Distributions were analysed using multivariate methods (two‐way indicator species analysis and detrended correspondence analysis) for each scale. Comparison of results allows recognition of several floristic elements and sectors (i.e. Balearic, Murcian‐Almerian, south western) common to all three scales, whereas other regions are assigned to different sectors depending on the grid size considered. As a consequence of the increase in detail, characteristics such as number of sectors, the outline of boundaries and continuity or fragmentation of the areas also change. These factors are discussed.
Geographic patterns of genetic diversity in Poulsenia armata (Moraceae): implications for the theory of Pleistocene refugia and the importance of riparian forest
Authors: Aide T. Mitchell , Rivera Elsie
Published: March 2003

Abstract. Tropical forests are species‐diverse communities, but we know very little about the geographical distribution of genetic diversity within a species. During the late Pleistocene, lower temperatures and rainfall reduced the distribution of tropical wet forests, and in Central America lowland species may have been limited to riparian habitats. Approximately 12,000 years bp, temperature and rainfall increased in Central America, the distribution of wet forest species expanded, and today the distribution of some species extends into southern Mexico. The distribution of genetic diversity, based on RAPD markers, among ten populations of Poulsenia armata (Miq.) Standl. (Moraceae) suggests that these populations did not originate from a single refugium or region in the late Pleistocene. The Central American populations had high genetic diversity and unique bands giving support to the hypothesis that populations of P. armata occurred in Central American during the late Pleistocene. The majority of genetic diversity was partitioned among populations and there was no geographical relationship among populations, suggesting that these populations were isolated for a long period and there has been little gene flow. Populations of P. armata may have persisted in riparian zones along the Caribbean coast during the late Pleistocene. Given that riparian forest can support high levels of biodiversity in ecological time, and they have played an important role during periods of climate change over geological time, their conservation is of utmost importance particularly with the threat of a rapid shift in climatic patterns.
Fossil pollen as a record of past biodiversity
Authors: Odgaard Bent Vad
Published: March 2003

Quaternary pollen records may contribute uniquely to the understanding of present plant diversity. Pollen assemblages can reflect diversity at community and landscape scales but the time resolution of most studies does not match that of modern ecological studies. Because of the complicating effects of differential pollen productivity and dispersal, pollen records do not directly reflect equitability aspects of vegetation diversity. Vegetation diversity indices other than S (the total number of taxa) are therefore not appropriate for pollen assemblages. As a measure of the species richness palynological richness is biased by the lack of taxonomic precision, by a possible interference on pollen dispersal from vegetation structure and by pollen representation. The nonlinear relationship between species richness and pollen‐taxa richness may be used in attempts to estimate past floristic richness from fossil pollen assemblages. Using a hypothetical example the strong effect of cover shifts in the vegetation affecting taxa with different representation (Rrel) values on observed palynological richness is demonstrated. It is suggested that estimates of relative pollen productivity should be used to guide the pollen sum on which pollen‐type richness is estimated by rarefaction techniques and this approach is illustrated using a paired site study of late Holocene diversity dynamics. The need for a modern training set relating pollen‐type richness to species richness, pollen productivity and vegetation structure is emphasized.
Habitat relationships of forest birds on Tutuila Island, American Samoa
Authors: Freifeld H. B.
Published: March 2003

Aim Our knowledge of landbirds on tropical Pacific islands is often comprised of brief, one‐time surveys. We know little of species’ habitat preferences, and this information is critical for understanding the resource requirements or population status of native species and the impacts of human activity on island birds.

LocationTutuila Island, American Samoa.

Methods The spatial patterns in forest birds were investigated. This island harbours large tracts of native forest, a variety of disturbed and non‐native forests, and some relatively healthy bird populations. The distribution of birds was correlated with forest types using habitat data collected at fifty‐seven sites and avian census data collected monthly for 1–4 years at these sites.

ResultsDifferences in location and in vegetation structure and composition between native and non‐native habitats are important influences on the distribution of birds on Tutuila. Among native species, for example, the purple‐capped fruit‐dove (Ptilinopus porphyraceus Temminck) is dependent upon native habitat, the Samoan starling (Aplonis atrifusca Peale) occurs in all habitats, and the cardinal honeyeater (Myzomela cardinalis Gmelin) is more abundant in low elevation, non‐native habitat.

ConclusionsThis research reinforces the importance of quantitative assessment of habitat relationships in the study and conservation of Pacific birds.
Making a mark: two thousand years of ecology, economy and worldview
Authors: Simmons Ian
Published: March 2003

We can make a history of the world as an ecological history of an empirical nature. But parallelling that is the history of human thought about nature. The two interact at both pragmatic and abstract levels but in essence the outcome is unpredictable and more akin to chaos theory than to environmental or technological determinism. So the pursuit of either environmentalist or cornucopian Utopias seems not only doomed to failure but likely to cause destruction along the way; a step by step improvisatory strategy seems the best we can do.
Using between‐model comparisons to fine‐tune linear models of species ranges
Authors: Cumming Graeme S.
Published: March 2003

Aim To offer an objective approach to some of the problems associated with the development of logistic regression models: how to compare different models, determination of sample size adequacy, the influence of the ratio of positive to negative cells on model accuracy, and the appropriate scale at which the hypothesis of a non‐random distribution should be tested.

Location Test data were taken from Southern Africa.

Methods The approach relies mainly on the use of the AUC (Area under the Curve) statistic, based on ROC (threshold Receiver Operating Characteristic) plots, for between‐model comparisons. Data for the distribution of the bont tick Amblyomma hebraeum Koch (Acari: Ixodidae) are used to illustrate the methods.

Results Methods for the estimation of minimum sample sizes and more accurate hypothesis‐testing are outlined. Logistic regression is robust to the assumption that uncollected cells can be scored as negative, provided that the sample size of cells scored as positive is adequate. The variation in temperature and rainfall at localities where A. hebraeum has been collected is significantly lower than expected from a random sample of points across the data set, suggesting that within‐site variation may be an important determinant of its distribution.

Main conclusions Between‐model comparisons relying on AUCs can be used to enhance objectivity in the development and refinement of logistic regression models. Both between‐site and within‐site variability should be considered as potentially important factors determining species distributions.
Families with highest proportions of rare species are not consistent between floras
Authors: Edwards Will , Westoby Mark
Published: March 2003

Aim

In this study we compare the incidence of rarity within lineages between three floras: Australia, North America and New Zealand.

Methods

We used published data for absolute numbers of species and for numbers of rare species to ask three questions: 1. Do families have similar proportions of rare species in different floras? 2. Can proportions of rare species within families be interpreted with reference to biogeographic history of particular floras? and 3. Is the proportion of rare species consistent between families and genera within each flora?

Results

Within families in each flora, genera usually had similar proportions of rare species; indicating processes determining rarity are in general not operating differentially within families. However, in comparisons within‐family between floras, approximately 62% of comparisons showed significant differences in the proportion of rare species.

Main conclusions

These results imply that there are no general rules whereby the particular traits a family possesses are conducive to rarity wherever they occur. Rather, such attributes must exert influence conditionally, in conjunction with the biogeographical and competitive setting where speciation and extinction or persistence has occurred.
Pollen‐based biomes for Beringia 18,000, 6000 and 0 14C yr bp†
Authors: Edwards M. E. , Anderson P. M. , Brubaker L. B. , Ager T. A. , Andreev A. A. , Bigelow N. H. , Cwynar L. C. , Eisner W. R. , Harrison S. P. , Hu F.‐S. , Jolly D. , Lozhkin A. V. , MacDonald G. M. , Mock C. J. , Ritchie J. C. , Sher A. V. , Spear R. W. , Williams J. W. , Yu G.
Published: March 2003

The objective biomization method developed by Prentice et al. (1996)
for Europe was extended using modern pollen samples from Beringia and then applied to fossil pollen data to reconstruct palaeovegetation patterns at 6000 and 18,000 14C yr
bp.

The predicted modern distribution of tundra, taiga and cool conifer forests in Alaska and north‐western Canada generally corresponds well to actual vegetation patterns, although sites in regions characterized today by a mosaic of forest and tundra vegetation tend to be preferentially assigned to tundra. Siberian larch forests are delimited less well, probably due to the extreme under‐representation of Larix in pollen spectra.

The biome distribution across Beringia at 6000 14C yr
bp was broadly similar to today, with little change in the northern forest limit, except for a possible northward advance in the Mackenzie delta region. The western forest limit in Alaska was probably east of its modern position.

At 18,000 14C yr bp the whole of Beringia was covered by tundra. However, the importance of the various plant functional types varied from site to site, supporting the idea that the vegetation cover was a mosaic of different tundra types.
Biomes of western North America at 18,000, 6000 and 0 14C yr bpreconstructed from pollen and packrat midden data
Authors: Thompson Robert S. , Anderson Katherine H.
Published: March 2003

A new compilation of pollen and packrat midden data from western North America provides a refined reconstruction of the composition and distribution of biomes in western North America for today and for 6000 and 18,000 radiocarbon years before present (14C yr bp).

Modern biomes in western North America are adequately portrayed by pollen assemblages from lakes and bogs. Forest biomes in western North America share many taxa in their pollen spectra and it can be difficult to discriminate among these biomes. Plant macrofossils from packrat middens provide reliable identification of modern biomes from arid and semiarid regions, and this may also be true in similar environments in other parts of the world. However, a weighting factor for trees and shrubs must be used to reliably reconstruct modern biomes from plant macrofossils.

A new biome, open conifer woodland, which includes eurythermic conifers and steppe plants, was defined to categorize much of the current and past vegetation of the semiarid interior of western North America.

At 6000 14C yr bp, the forest biomes of the coastal Pacific North‐west and the desert biomes of the South‐west were in near‐modern positions. Biomes in the interior Pacific North‐west differed from those of today in that taiga prevailed in modern cool/cold mixed forests. Steppe was present in areas occupied today by open conifer woodland in the northern Great Basin, while in the central and southern Rocky Mountains forests grew where steppe grows today. During the mid‐Holocene, cool conifer forests were expanded in the Rocky Mountains (relative to today) but contracted in the Sierra Nevada. These differences from the forests of today imply different climatic histories in these two regions between 6000 14C yr bpand today.

At 18,000 14C yr bp, deserts were absent from the South‐west and the coverage of open conifer woodland was greatly expanded relative to today. Steppe and tundra were present in much of the region now covered by forests in the Pacific North‐west.
Richness and diversity of helminth communities in tropical freshwater fishes: empirical evidence
Authors: Choudhury Anindo , Dick Terry A.
Published: March 2003

Aim

Published information on the richness and diversity of helminth parasite communities in tropical freshwater fishes is reviewed in response to expectations of species‐rich parasite communities in tropical regions.

Location

Areas covered include the tropics and some subtropical areas. In addition, the north temperate area of the nearctic zone is included for comparison.

Methods

Data from 159 communities in 118 species of tropical freshwater fish, summarized from 46 published studies, were used for this review. Parasite community descriptors used in the analyses included component community richness and calculated mean species richness. Data from 130 communities in 47 species of nearctic north temperate freshwater fish were summarized from 31 studies and used for comparison.

Results

The component helminth communities of many tropical freshwater fish are species‐poor, and considerable proportions of fish from certain parts of the tropics, e.g. West African drainages, are uninfected or lightly infected. Mean helminth species richness was low and equaled or exceeded 2.0 in only 22 of 114 communities. No single group of helminths was identified as a dominant component of the fauna and species composition was variable among and within broader geographical areas. The richest enteric helminth assemblages were found in mochokid and clariid catfish with a mixed carnivorous diet, whereas algal feeders, herbivores and detritivores generally had species‐poor gut helminth communities. Comparisons indicated that certain areas in the north temperate region had higher helminth species richness in fishes than areas in the tropics.

Main conclusions

Expectations of high species richness in helminth communities of tropical freshwater fishes are not fulfilled by the data. Direct comparisons of infracommunities and component communities in host species across widely separated phylogenetic and geographical lines are inappropriate. Examination of latitudinal differences in richness of monophyletic parasite groups or of compound communities may uncover patterns different from those found in this study. Richness of helminth communities may be ultimately determined not by the number of host species present but by the degree of divergence of host lineages and by their diversification modes. A phylogenetic framework for hosts and parasites will reveal if increased host species richness within host clades, when host speciation is accompanied by habitat or diet specialization, or both, leads to lower helminth diversity in host species by fragmentation of a core helminth fauna characteristic or specific of the larger host clade. This pattern may be analysed in the context of cospeciation and acquisition from other unrelated hosts (host‐sharing or host‐switching).
Biogeographic patterns and cryptic speciation in bryophytes
Authors: Shaw Jonathan
Published: March 2003

Bryophytes (mosses, liverworts, hornworts) typically have broad geographical distributions that span two or more continents. Many species show classic patterns of disjunction that are similar to those found in many other groups of organisms (e.g. eastern Asia–eastern North America), and which are thought to result from fragmentation of previously continuous ranges (i.e. vicariance). However, in the bryophytes, these disjunctions often occur at the infra‐specific level and suggest that morphological uniformity may belie complex underlying genetic structure. Recent demonstrations of cryptic speciation, revealed by analyses of isozymes and DNA sequence variation, support the interpretation that genetic subdivision has occurred within some morphologically uniform species. Evidence for cryptic or nearly cryptic speciation exists for seven species of liverworts and seven mosses. In most (but not all) cases, cryptic species have broadly overlapping geographical ranges, although many are ecologically differentiated. Future work should focus on species that display ‘classic’ patterns of disjunction at higher taxonomic levels in other organisms (e.g. eastern North America–eastern Asia, eastern or western North America–Europe, Gondwanic), and should utilize explicitly phylogenetic approaches.
Distribution of bird species richness at a regional scale in tropical dry forest of Central America
Authors: Gillespie Thomas W. , Walter Hartmut
Published: March 2003

Aim

The objectives of this study were to identify landscape and habitat characteristics associated with bird species richness at a regional scale. In particular, we examined how these variables affect resident bird, forest bird, fruit‐eating bird and restricted‐range bird species richness in forest fragments.

Location

Study sites were located in seven decreed reserves in Costa Rica and Nicaragua that contain some of the largest and best‐protected fragments of tropical dry forests in central America.

Methods

Bird censuses were undertaken using point counts at each site and compared with landscape metrics and habitat characteristics of reserves.

Results

Forest cover within reserves, zoochoric species richness, tree and shrub species richness, and tree height were associated with resident, forest and fruit‐eating bird species richness in tropical dry forests.

Main conclusions

The distribution of bird species richness in tropical dry forests of central America can be attributed to a number of interacting factors. Conservation priorities based on bird species richness should focus on Santa Rosa National Park, while the Chacocente and Cosiguina reserves deserve a high priority for conservation within Nicaragua.
Stability of boreal forest stands during recent climate change: evidence from Landsat satellite imagery
Authors: Masek Jeffrey G.
Published: March 2003

Aim

To detect possible expansion of boreal forest stands in response to recent warming. Previous modelling studies have concluded that major shifts in vegetation patterns, including changes in boreal forest extent, could arise during the next two centuries under global warming scenarios. However, field investigations of tree stands at ecotones have so far revealed little indication of stand response to warming during the last 100 years. This study uses a c. 25‐year record of Landsat satellite observations to quantify changes in forest stand extent in two areas of northern Canada.

Location

Two regions of northern Canada, near Richmond Gulf, Quebec, and Great Slave Lake, north‐west Territories.

Methods

Normalized‐difference vegetation index (NDVI) plots across forest‐tundra boundaries were obtained from radiometrically corrected Landsat imagery acquired during the 1970s and 1990s. These curves were evaluated to look for changes over the c. 25‐year period related to forest stand expansion.

Results

Although forest‐tundra boundaries could be clearly mapped from the satellite data, no obvious change in forest boundaries was apparent during the duration of the image time series, constraining recent geographical expansion rates to <200–300 m per century. Also, no evidence for local expansion of forest stands (e.g. within sheltered valleys) was found.

Main conclusions

The results are consistent with field observations, and suggest that, at the moment, boreal forest extents remain basically stable. This may reflect inherent lags between forest response and climate change, or competitive pressures between tree stands and surrounding tundra and herbaceous vegetation.
Biogeography of the Amazon molly, Poecilia formosa
Authors: Schlupp Ingo , Parzefall Jakob , Schartl Manfred
Published: March 2003

Aim

The unisexual Amazon molly (Poecilia formosa) is a clonal, all‐female fish but depends on sperm of heterospecific males to trigger embryogenesis. Thus, one very important factor shaping its geographical range is the presence of suitable host males. Several species of the genus Poecilia from Central America, Mexico and the USA can provide sperm in the laboratory, but are not utilized as hosts in nature. Consequently the potential geographic range of the Amazon molly is much larger than the actual range. This raises the question of what is responsible for the biogeographical range of the Amazon molly?

Location

Southern USA, Mexico and Central America.

Methods

We review the current data available for the distribution of the Amazon molly. We further tested whether salinity might hinder the dispersal of the species.

Results

Amazon mollies tolerate marine conditions. We review the available data on recent and human influenced introductions of Amazon mollies.

Main conclusions

We argue that male preferences are not responsible for the current range. We propose that prevailing near‐shore marine currents act as an effective barrier against further dispersal. Furthermore, we discuss recent changes in the biogeography of the Amazon molly.
Digitization and geo‐referencing of botanical distribution maps
Authors: Schölzel Christian A. , Hense Andreas , Hübl Peter , Kühl Norbert , Litt Thomas
Published: March 2003

Aim

In many fields of research, valuable information is stored in atlases and maps which are only available as printed media. Scientists who are interested in computational analysis often seek to digitize the data to make it accessible for numerical calculations. In this paper, an approach using the example of digitizing distribution maps taken from plant‐taxonomic atlases is described. For this purpose, a software tool has been built for application in the Sonderforschungsbereich 350 `Interactions between and Modelling of Continental Geosystems' at the University of Bonn. Its functionality has to be simple in use and capable of transforming fields drawn on geographical maps into grid data even where the type of map projection is unknown.

Location

As an example, plant distributions over Europe and Asia have been digitized.

Methods

To achieve this aim through an objective statistical analysis, the local deterministic approximation has been used for geo‐referencing.

Results

For this reason the development of a new software tool was required. Although there is a large market for related software from Geographical Information Systems (GIS), none of the available GIS‐programs appeared to be capable of geo‐referencing maps with unidentified projections. Rather than to give a product comparison, this paper aims on the methodology and mathematical formalism.

Main conclusions

The developed algorithm is a handy tool to capture data from maps based on obscure projections. Valuable historical maps, which are problematic for standard GIS‐programs, can be made accessible for modern research work.
Biogeography of living and fossil Nitellopsis (Charophyta) in relationship to new finds from Morocco
Authors: Soulié‐Märsche I. , Benammi M. , Gemayel P.
Published: March 2003

Aim  To document the distribution of two closely related macrophyte species, the fossil Nitellopsis (Tectochara) merianii (A. Braun ex Unger) Grambast & Soulié‐Märsche and Nitellopsis obtusa (Desvaux) J. Groves, the single living species of genus Nitellopsis and to draw the relationships between first finds of N. merianii in North Africa and previously known records.

Location  South part of the High Atlas Range, Aït Kandoula basin, Morocco.

Methods  New finds of fossil charophyte gyrogonites were determined and illustrated. Using a large bibliographic database of both fossil and extant charophytes, we depict the biogeographical distribution N. merianii and N. obtusa and summarize the ecological requirements of N. obtusa as a modern analogue.

Results  The Aït Kandoula deposits, dated by magnetostratigraphy and vertebrate fossils to Upper Miocene, provided the first fossil populations of N. merianii in Africa. The distribution patterns of the Tertiary N. merianii and the living N. obtusa superimpose on a large area that extends from Spain to East Asia and characterize them as typically Eurasian taxa indicative for permanent, relatively cold and deep freshwater lakes. During the Quaternary, similar palaeolakes in the Sahara were colonized by N. obtusa.

Main conclusions  The presence of the Eurasian species N. merianii in North Africa is the result of dispersal by migratory waterbirds and attests to N–S migration occurring during the Upper Miocene (10–5 Myr ago). Gyrogonites imported from Southern Europe could germinate and fulfil their life cycle so as to form a new seed bank of gyrogonites because they had been deposited in a suitable environment consisting of a freshwater mountain lake.
Implementing advanced practice: identifying the factors that facilitate and inhibit the process
Authors: Woods Leslie Peter
Published: March 2003

• This paper reports the preliminary results of research investigating the factors that help or hinder advanced nurse practitioners as they attempt to implement new roles in clinical practice.

• Multiple facilitating and inhibiting factors are identified, the majority of which are shared across various clinical settings.

• Factors fall into three categories: re‐negotiating relationships; becoming an advanced practitioner; and the clinical context and deployment.

• Whilst the results of this case study research are not necessarily generalizable, they provide evidence of the lived experience of advanced nurse practitioners attempting to implement new roles in a variety of clinical settings following their graduation from a Master's degree programme.
The importance of information giving for patients newly diagnosed with cancer: a review of the literature
Authors: Mills Moyra E. , Sullivan Kate
Published: March 2003

• The importance of information giving has been recognized and promoted in political, ethical and professional arenas and this has ultimately resulted in the publication of a vast amount of literature relating to the subject.

• This literature review considers the functions of patient information and the factors influencing information seeking for patients who have been diagnosed with cancer.

• Methods of providing information are discussed and the nurse’s role in information giving is examined.

• A number of core problems are highlighted in relation to information giving. These problems, and possible reasons for them, are subsequently critically analysed.

• Finally, the literature relating to information needs of patients with cancer is evaluated and five key needs identified.
Quality of nursing care perceived by patients and their nurses: an application of the critical incident technique. Part 1
Authors: REDFERN SALLY , NORMAN IAN
Published: March 2003

• The aims of the study were to identify indicators of quality of nursing care from the perceptions of patients and nurses, and to determine the congruence between patients' and nurses' perceptions.

• The paper is presented in two parts. Part 1 includes the background and methods to the study and the findings from the comparison of patients' and␣ nurses' perceptions. Part 2 describes the perceptions of patients and nurses,␣ and the conclusions drawn from the study as a whole.

• Patients and nurses in hospital wards were interviewed using the critical incident technique.

• We grouped 4546 indicators of high and low quality nursing care generated from the interview transcripts into 316 subcategories, 68 categories and 31 themes.

• Congruence between patients' and nurses' perceptions of quality was high and significant, although there was some difference of emphasis.
Improving hand hygiene in community healthcare settings: the impact of research and clinical collaboration
Authors: Gould Dinah , Gammon John , Donnelly Michael , Batiste Louise , Ball Eileen , Carneiro De Melo Alexandra M. S. , Bsc Alidad , Miles Roger , Halablab Mahmoud
Published: March 2003

• Observation of nursing activities and bacteriological studies undertaken with a sample of nurses employed in a community NHS trust indicated that considerable scope for cross infection existed during domiciliary visits.

• Poor conditions in patients’ homes compromised nurses’ ability to perform hand hygiene effectively, increasing risks.

• A clinical trial indicated that carriage of medically significant bacteria likely to contribute to cross infection could be reduced by applying an antiseptic cream which exhibited residual effectiveness.

• An audit of hand hygiene throughout the inner city trust indicated the need to pay greater attention to hand hygiene, especially during home nursing visits. The situation was less acute in a rural trust where a second audit was performed for comparative purposes.

• The motivation of clinical staff to improve hand hygiene precautions was high.
Evaluating support surfaces for patients in transit through the accident and emergency department
Authors: Tarpey Aideen , Gould Dinah , Fox Carolyn , Davies Peter , Cocking Maggie
Published: March 2003

• Little attention has been given to pressure area care for patients admitted via the accident and emergency department (A & E) in UK hospitals, despite evidence that they may wait for considerable periods on hard surfaces, placing them at risk of tissue damage.

• The literature was searched, and in the absence of existing guidelines to evaluate the suitability of the standard hospital trolley for use with emergency admission patients, criteria were developed by consensus among stakeholders with relevant expertise who were employed in an acute NHS hospital trust.

• Audit of the existing patient support surfaces using these criteria revealed deficiencies in all of them. Some of the problems identified were related to deterioration of the equipment; others were related to its design.

• The criteria were used to inform the purchase of new equipment, and a system of auditing to improve pressure area care for emergency admission patients has been established in the trust.

• The initiative has also drawn attention to significant omissions in the literature relating to pressure area care, including the need to evaluate patient comfort and inclusion of consumer views.
Promoting autonomy and independence for older people within nursing practice: an observational study
Authors: Davies Sue , Ellis Lorraine , Laker Sara
Published: March 2003

• Although autonomy and independence are widely held to be important goals of care for older people, these terms lack precise definition and operationalization in the literature.

• This paper reports on observational data gathered as part of an evaluation of educational programmes in the nursing care of older people.

• Strategies which appear both to promote and inhibit autonomy and independence of older patients in a range of care settings are described.

• Recommendations are made for further research to explore the extent to which autonomy and independence are appropriate goals of care for older people with cognitive impairment.
Peer evaluation in nurses’ professional development: a pilot study to investigate the issues
Authors: Vuorinen Riitta , Tarkka Marja‐Terttu , Meretoja Riitta
Published: March 2003

• Peer evaluation in nursing is a method by which the nurse evaluates the work of a peer, according to set evaluation criteria.

• The aim of the study was to clarify the potential significance of peer evaluation with regard to nurses’ career development and relates to the introduction of a career development programme for nurses in a Finnish University Hospital.

• The research concepts were created on the basis of literature analysis. The concepts served as a basis for data collection, and five open‐ended questions were devised from them. Informants (n = 24) gave free‐form essay‐type answers to these questions. The material was analysed using qualitative content analysis.

• The results indicate that self‐evaluation constitutes the basis for peer evaluation. Peer evaluation allows nurses to give and receive professional and personal support promoting professional development. Professional support offers possibilities for change and alternative action. Personal support requires respect for the peer’s equality and individuality. Personal peer support can decrease feelings of uncertainty and insecurity caused by work.

• The conclusion is drawn that peer evaluation is a means of promoting nurses’ professional development to further on‐the‐job learning in collaboration with peers.
The use of antipyretic medications in the prevention of febrile convulsions in children
Authors: Purssell Edward
Published: March 2003

• Febrile convulsions are a relatively common outcome in paediatric febrile illness, although it is not known why some children suffer these.

• Antipyretic medications may form the basis for some treatment regimens, although they are not recommended in published guidelines.

• There is little evidence that the prophylactic use of antipyretics has any effect in reducing the incidence of febrile convulsions.

• Consequently, educational interventions aimed at reducing parental fear and helping them to care for their children during febrile illnesses may be more efficacious.
The development of a national guideline on the management of leg ulcers
Authors: McInnes  , Cullum  , Nelson  , Luker  , Duff
Published: March 2003

• This paper describes the development of an evidence‐linked clinical guideline for the management of uncomplicated venous leg ulcers.

• Guidelines are developed to provide recommendations for clinical practice which are based on summaries of good quality research evidence.

• The aim of the guideline discussed in this article is to direct primary health care practitioners to the most effective method of assessment and treatment of venous leg ulcers and to discourage practices that do not have convincing or sufficient evidence of effectiveness.

• The three most important steps to the development of a valid clinical guideline are: basing recommendations on the best available evidence; explicit linkage between guideline recommendations and quality of evidence; and the involvement of a multidisciplinary group.

• The steps are discussed in relation to the development of the guideline alongside an introductory presentation on the role guidelines can play in improving practice.

• Issues arising from guideline development such as valid ways of obtaining patient input and lack of evidence are also discussed.
Developing occupational standards: a learning disabilities project
Authors: Jowett Rosalynd , Wellens Ben
Published: March 2003

• Occupational standards are often seen as cumbersome and inappropriate to a vocational curriculum such as nursing. However, the term fitness for practice is once more being used to focus the minds of educationalists and practitioners in healthcare delivery on the goal in preparing practitioners for the future.

• The project reported here was guided jointly by staff from a higher education institution and an NHS trust and involved practitioners in designing occupational standards with a view to using them in practice and incorporating them into the preregistration curriculum.

• The pivotal structure in this process was the focus group which, with tenacity and commitment, designed, developed and structured standards which were realistic and relevant to healthcare delivery.
Patient participation in bedside reporting on surgical wards
Authors: Timonen Leena , Sihvonen Marja
Published: March 2003

• Increasingly nowadays, patients have an opportunity to take part in nurses’ reporting sessions via bedside reporting.

• The aim of this study was to compare nurses’ and patients’ opinions of the purpose of bedside reports, patient participation in bedside reporting sessions, and factors that promote or prevent their participation.

• Data were collected by a questionnaire survey of nurses (N=118) and patients (N=74). A response rate of 81% was achieved in both groups. Additionally, 76 bedside reporting sessions were observed.

• According to patients, the main reasons for not participating were tiredness, difficulties in formulating questions, lack of encouragement, difficulties with the language used, nurses concentrating more on their papers than on them, and the reporting sessions were too short.

• Nurses reported that patients took a more active part in reporting sessions than patients themselves thought. The average time spent on each patient’s report was three minutes.
Spirituality: its relevance and purpose for clinical nursing in a new millennium
Authors: Kendrick Kevin David , Robinson Simon
Published: March 2003

• Nurses often make a link between spirituality and religion. This is evidenced in nursing documents when comments about the patient’s religious faith are placed in the space devoted to spirituality.

• While religion may inform and offer direction to an individual’s spirituality the two concepts are not the same. In terms of analogy, hydrogen and oxygen combine to make water although each brings its own defining characteristics to balance the chemical equation.

• Thus, there may be a synergy and symbiosis between religion and spirituality but the essence of each remains unique; indeed, a person’s spirituality can thrive irrespective of religious creed – orthodox or otherwise.

• In this paper, we will develop a narrative that articulates and offers the defining characteristics of spirituality. This will be coupled with a framework that seeks to explain the workings and dynamics of spirituality in clinical nursing.