bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bladder instability: a re‐appraisal of classical experimental approaches and development of new therapeutic strategies
Authors: Boselli C. , Govoni S. , Condino A. M. , D'Agostino G. 
Published: March 2003

Summary 1 Despite the growing social interest in human urinary tract disorders, the aetiology of detrusor instability remains poorly understood. Myogenic and neural impairment of detrusor activity caused by CNS or autonomic injuries can results in dysfunctions of normal voiding of the bladder such as urinary incontinence. 2 The contractility of human detrusor smooth muscle is critically dependent on acetylcholine‐induced muscarinic receptor activation. Biochemical and functional in vivo and in vitro studies suggest the presence of an heterogeneous population of muscarinic receptor subtypes (M1–M4) localized at muscular and neutral sites. There is increasing evidence on the prejunctional auto‐ and hetero‐regulation of acetylcholine release from parasympathetic nerve endings in modulating detrusor muscle contraction during micturition. 3 Activation of P2X purinoreceptors closely associated with the parasympathetic varicosities seems to be implicated to varying extent in the contractility in normal or instable human detrusor. Interestingly, P2X1 subtype expression on smooth muscle increases considerably in the symptomatically obstructed bladder. A striking absence of P2X3 and P2X5 subtypes was observed in the cholinergic innervation of detrusor from patients with urgent incontinence. Thus, it is likely that alteration of the neural acetylcholine control can play a critical role in pathological states. 4 If the failures in storage and voiding can be recognized urodynamically, considerable difficulties remain in investigating the underlying functional changes especially because the study of the pathophysiology requires techniques that can be justified in animals but not in humans. 5 Recently, to solve this problem an alternative technique using human smooth muscle cells in culture has been developed. Human cell lines may be relevant in investigating the molecular pathways in physiological and pathological conditions. 6 The potential development of novel molecular therapeutic strategies such as gene therapy and tissue engineering is also discussed.
On the generation of diversity in archipelagos: a re‐evaluation of the Quinn‐Harrison ‘saturation index’
Authors: Mac Nally R. , Lake P. S. 
Published: March 2003

SummaryAimQuinn & Harrison (1988;Oecologia,75, 132)suggested that several small, isolated islands generally bore a higher diversity than fewer (or single) larger islands. They proposed a method by which the cumulative diversity of islands arranged small‐to‐large (‘STOL’) and large‐to‐small (‘LTOS’) could be used to identify how island area and species distributions interact to produce the system‐wide or ensemble diversity. From these curves, an ‘index of saturation’ (SI) was calculated to summarize the way in which diversity is generated on a given archipelago. Unfortunately, the method did not allow statistical judgements to be made. Our paper considers the reliability of the Quinn‐Harrison approach, especially in light of the inconsistency of its implications compared with ‘nestedness’ analyses.LocationThree example data sets are used: reptiles from the archipelagos of the Sea of Cortéz, breeding land‐birds from the Canary Islands, and stream invertebrates occupying rocks in the Steavenson River of central Victoria, Australia.MethodsWe refine the Quinn‐Harrison technique to produce a method by which the difference between the STOL and LTOS cumulative diversity curves can be gauged statistically (the ξ statistic). We also propose an alternative statistic (η)—which we believe to be more intuitive—that preferentially weights species occurring on few patches and that can be statistically assessed by using Monte Carlo simulation.ResultsThe basic Quinn‐Harrison technique is not reliable for diagnosing whether systems are characterized by STOL or LTOS patterns. The three example data sets provide the range of options for faunal‐diversity generation (STOL overlies LTOS, LTOS overlies STOL, and coincident). However, statistical analyses indicate that the patterns all are generated by the rarer species occupying larger islands. The results of the revised ξ statistic and especially the η statistic are consistent with this deduction, which in turn relate well with faunal‐nestedness analyses.Main conclusionsThere was a contradiction between the Quinn‐Harrison analyses, which suggested that most rarer taxa occurred in impoverished, smaller islands, and results of nestedness analyses, which indicated that the rarer taxa occurred on more speciose, larger islands. The resolution to this dilemma is that the Quinn‐Harrison diagram and saturation index are so flawed that they yield unreliable resultsvis a visthe generation of diversity on archipelagos.
Bergmann's rule in the ant lion Myrmeleon immaculatus DeGeer (Neuroptera: Myrmeleontidae): geographic variation in body size and heterozygosity
Authors: Arnett Amy E. , Gotelli Nicholas J. 
Published: March 2003

Summary Aim Geographic variation in body size and heterozygosity were surveyed for discrete populations of the ant lion, Myrmeleon immaculatus DeGeer, collected from the central and northeastern United States. LocationCollection sites were located in the central and eastern United States ranging from western Oklahoma to northern New York. Methods We collected 872 M. immaculatus larvae from thirty‐four collecting sites. At each site, we randomly sampled ant lion pits and collected between fifteen and fifty‐two larvae in total. Larvae were preserved in 95% ETOH for morphological analysis and frozen in a −80°C freezer for protein electrophoresis. We measured the body size of eighty‐five preserved adult M. immaculatus obtained from museum collections using head width as an indicator of body size. Five enzymes [GPI (glucose phosphate isomerase), MDH (malate dehydrogenase), PEP (peptidase), DIA (diaphorase) and SOD (superoxide dismutase)] were used in the heterozygosity analyses. Results Larval and adult body size increased with latitude, but decreased with elevation. Average heterozygosity, measured at five polymorphic loci, also increased significantly with latitude. Minimum temperature variance was the best predictor of body size, whereas precipitation and maximum temperature were the best predictors of heterozygosity. Populations were genetically differentiated from one another and showed a pattern of isolation by distance, as measured by Wright's Fst values and Nei's genetic distances. Main conclusions Sampling artifacts, heat conservation, character displacement, cell‐size variation, density‐dependent mortality, and differential dispersal probably cannot account for latitudinal variation in ant lion body size. Our results implicate the importance of diurnal photoperiod, which varies with latitude, but not with elevation. Because photoperiod often controls growth, diapause, and metamorphosis, it may be an important determinant of latitudinal clines in body size and life history of insects.
How to do BPA, really
Authors: Brooks Daniel R. , Van Veller Marco G. P. , McLennan Deborah A. 
Published: March 2003

AimRecent comparisons of different approaches to historical biogeography have suffered in part because Brooks Parsimony Analysis (BPA) has been characterized as a one‐step process following protocols proposed in 1981. Subsequent modifications have resulted in a two‐step methodology. This contribution presents the mechanics and applications of those modifications.MethodsThe first step, or Primary BPA, which is similar to the original BPA but with modifications proposed by Wiley (1986, 1988a, b), is used to assess whether or not there is support for a single general area cladogram. The second step, Secondary BPA, proposed by Brooks (1990), depicts exceptions to the general area cladogram explicitly by duplicating areas having a reticulate history.ResultsThe analytical basis of area duplication in secondary BPA is explained more fully than in previous accounts, and the manner in which secondary BPA explicitly depicts falsification of the null hypothesis of simple vicariance is presented for four general cases.Main conclusionsBPA, as fully implemented, is capable of accounting for the complexity of speciation, dispersal and extinction events in a historical biogeographic context without removing or modifying input data from basic phylogenies, so long as at least three clades are analysed simultaneously to provide a distinction between general and special distribution elements.
Another look at the richness of helminth communities in tropical freshwater fish
Authors: Poulin Robert 
Published: March 2003

AimRecently,Choudhury & Dick (2000)argued that helminth parasite communities in tropical freshwater fish are not richer than those in temperate fish. Here their data is re‐examined in an analysis that takes into account important confounding variables, and their conclusions are revisited.LocationThe data set covers fish species from many tropical areas and from the north temperate area of the nearctic zone.MethodsMultivariate analyses are used to control the influence of sampling effort and host body size, two factors that may confound the comparison between tropical and temperate helminth communities. In addition, phylogenetically independent contrasts are derived from the fish taxa included in the data set and used to remove the potential effect of shared phylogenetic history on the richness of helminth communities.ResultsBoth host body size and the number of hosts examined correlated positively with the number of species found in a helminth community, and fish body size also correlated with measures of richness corresponding to the mean number of helminth species per fish individual. After controlling for the effects of these two confounding variables, temperate helminth communities still had higher richness scores than those from the tropics. The analysis using independent contrasts removed the remaining potential confounding factor, i.e. host phylogeny, and it again showed that helminth communities of temperate fish taxa are richer than those of related fish taxa from the tropics. This last result, however, applies only to the number of helminth species found in a helminth community, and not to the mean number of helminth species per individual fish host.Main conclusionsThe general conclusion of the present study is similar to that ofChoudhury & Dick (2000). However, the new analysis has ruled out some confounding factors as potential explanations for the patterns, and has served as an indirect test of a version of the area hypothesis (i.e. helminth diversity is explained by host size). The reason why this latitudinal gradient in richness runs counter to those usually observed in other plant and animal assemblages remains to be found.
The frost resistance of ericoid heath plants in the British Isles in relation to their biogeography
Authors: Bannister P. , Polwart A. 
Published: March 2003

AimTo determine whether rare British ericoid heaths are restricted to the oceanic fringes of south‐western England and western Ireland because of their sensitivity to frost.LocationThe Wirral Peninsula, Cheshire, England. Shoots of the common heaths (Calluna vulgaris (L.) Hull, Erica tetralix L., Erica cinerea L.) were obtained from Thurstaston Heath and those of the rarer heaths (E. mackaiana Bab., E. ciliaris L., E. erigena R. Ross and E. vagans L.) from collections of known provenance in Ness Gardens.MethodsFrost resistance of cut shoots was determined at approximately monthly intervals between February 1994 and March 1995. Shoots were exposed to a range of freezing temperatures and scored for damage. Freezing resistance was determined as the temperature that caused 50% damage to the shoots.ResultsThe frost resistance of the common heaths was in accord with their geographical distribution. Calluna vulgaris and E. tetralix extend furthest north and east in Europe and developed the greatest frost resistance in winter (< –20 °C). Erica cinerea is widespread throughout the British Isles with an oceanic south‐western distribution in Europe and was resistant to only –13 °C. Erica vagans has a similar frost resistance to E. cinerea but has a restricted distribution in the British Isles, whilst the other rare heaths are more frost resistant than either E. cinerea or E. vagans. The frost resistance of all species increased with shorter daylengths and decreased with higher temperatures, suggesting that global warming might result in increased sensitivity to frost in these species.Main conclusionsWhilst the distributions of the common heath species are in accord with their frost resistance, those of the rarer heaths are not. Consequently, factors other than susceptibility to cold winters must account for the restriction of rare species of Erica to the southern and western fringes of Britain and Ireland.
A comparison of the tropical montane pteridophyte floras of Mount Kinabalu, Borneo, and Parque Nacional Carrasco, Bolivia
Authors: Kessler Michael , Parris Barbara S. , Kessler Elke 
Published: March 2003

AimTo compare the species richness, and taxonomic and life‐form composition of tropical montane pteridophyte floras on two well‐documented sites: Mount (Mt) Kinabalu, Sabah, Borneo and Parque Nacional (PN) Carrasco, central Bolivia.MethodsUsing published lists, we compared the elevational distribution of overall species richness, specific pteridophyte families, and of life‐forms along both study sites. Additionally, we compared point‐diversity by establishing 108 plots of 400 m2 at PN Carrasco, and 15 such plots at Mt Kinabalu and three at a lowland site at Danum Valley in south‐eastern Sabah, Borneo (200 m).ResultsThe numbers of species, genera, and families recorded on Mt Kinabalu were 14–23% higher than at PN Carrasco, most probably as a result of more intensive long‐term collecting activity. Opposed to this, species richness per 400 m2 plot was somewhat higher at PN Carrasco, especially amongst epiphytes at mid‐elevations. Overall, there was a remarkable similarity in the elevational distribution of species numbers, of individual pteridophyte families, and of life‐forms. Major differences included a more pronounced peak of species richness at 1500 m on Mt Kinabalu, considerably higher species numbers of Elaphoglossum at PN Carrasco and of Grammitidaceae at Mt Kinabalu, and a higher proportion of debris‐trapping epiphytes and lithophytic species at Mt Kinabalu and of terrestrial herbs at PN Carrasco.Main conclusionsThe majority of present‐day species of the studied pteridophyte floras evolved largely independently from about 66–100 common ancestors. The striking convergence of the pteridophyte floras of both sites indicates that the taxonomic and morphological composition of the pteridophyte floras is subject to selective pressure, and that specific pteridophyte families are evolutionarily pre‐disposed to occupy specific ecological niches.
The species–area relationship does not have an asymptote!
Authors: Williamson Mark , Gaston Kevin J. , Lonsdale W. M. 
Published: March 2003

AimTo attack a widespread myth.LocationWorld‐wide.MethodsSimple mathematical logical and empirical examples.ResultsAs both species and area are finite and non‐negative, the species–area relationship is limited at both ends. The log species–log area relationship is normally effectively linear on scales from about 1 ha to 107 km2. There are no asymptotes. At the intercontinental scale it may get steeper; at small scales it may in different cases get steeper or shallower or maintain its slope.Main conclusionThe species–area relationship does not have an asymptote.
The potential effects of sexual reproduction and seedling recruitment on the maintenance of red maple (Acer rubrum L.) populations at the northern limit of the species range
Authors: Tremblay M. Francine , Bergeron Yves , Lalonde Danielle , Mauffette Yves 
Published: March 2003

AimFor this study, we wanted to evaluate the reproductive potential of northern red maple (Acer rubrum L.) populations to identify the possible factors responsible for the scattered distribution pattern of these northern populations.LocationSamara production and long‐term establishment of seedlings were observed along a north–south transect crossing the transition zone between continuous and discontinuous stands of red maple (47°80′–49°27′ N) in western Quebec.MethodsEleven populations of red maple were selected along a latitudinal gradient extending to the northern limit of the species. Seed traps were placed in each stand and distributed under the canopy of mature red maple trees. Seed abundance was tracked for 6 years from 1988 to 1993. Phenological observations were made in 1992 and 1993 at Roquemaure (Roq), a site located at the centre of the latitudinal gradient. Red maple trees were randomly selected within the population; counts of flower buds, pollinated buds and samaras produced were made in 1992–93. Samaras were collected from each branch immediately before dispersal and counted. During the summer of 1987, seedlings (< 1 cm d.b.h.) were collected and aged at each site in twenty 1 m2 quadrants and age of the seedlings (< 1 cm d.b.h.) was determined by counting the annual scars left by terminal buds.ResultsSamaras were produced even at the northern limit but large yearly variations were observed. Over the 6‐year period we counted 3 years (1989, 1990, 1993) when samara production was high, and 3 years (1988, 1991, 1992) when production was low. Phenological observations indicate that the occurrence of spring frosts at the time of flower bud flushing could contribute to decreasing the abundance of seeds. The age structure of southern localities had a relatively constant production of seedlings, as indicated by an inverse J‐shaped distribution. However, the five northernmost localities show sporadic recruitment.Main conclusionsPopulations at the northern limit are maintained essentially through vegetative reproduction and infrequent sexual recruitment. Our results indicate that regeneration within established stands through sexual recruitment is possible in all of the populations we studied. This potential becomes very low at more northerly sites and sexual reproduction alone would be unlikely to ensure successful stand regeneration. Without major disturbances in those stands, shade tolerant conifer species such as balsam fir (Abies balsamea) or black spruce (Picea mariana) would readily dominate the canopy. The discontinuous distribution of red maple stands at the northern limit is the consequence of either a random colonization of few sites during a better climatic period or remnants of a much larger distribution that has been constrained because of climatic deterioration.
Regional patterns of biodiversity in New Guinea animals
Authors: Heads Michael 
Published: March 2003

AimTo assess regional patterns of biodiversity levels in the New Guinea region by counting numbers of species of different groups in 1° grid squares.LocationThe New Guinea region.MethodsPanbiogeographical analysis [Craw, R.C., Grehan, J.R. & Heads, M.J. (1999) Panbiogeography: tracking the history of life. Oxford University Press, New York].ResultsThe following taxa were analysed: three genera of cicadas (Homoptera), freshwater fishes, snakes, and the four terrestrial orders of mammals in the region – monotremes, marsupials, bats and rodents. A total of 622 species (and subspecies) was analysed and the different centres of diversity in the various groups of animals are related to the three main geological regions of the country: Australian craton, accreted terranes, and Cainozoic volcanic arcs.Main conclusionsFreshwater fishes are most diverse in the lower Fly – Merauke region, on the southern, Australian craton portion of New Guinea. Marsupials are the only other group with a main massing on the craton (at the Kubor Mountains area). Snakes are most diverse in the trans‐Fly region, like freshwater fishes, and also around Port Moresby. All the other groups have centres of diversity either on the craton margin or outboard of it on different accreted terranes of the New Guinea orogen. In the groups studied, only bats have a significant, albeit secondary, massing on the Bismarck Archipelago. Other terrestrial vertebrates with centres of diversity on the Bismarck Archipelago include the diverse frog genus Platymantis. The regions north and east of New Guinea (Bismarck Sea plate, Solomon Sea plate) are now occupied mainly by sea and volcanic island arcs, but biogeographers and geologists have suggested this as the site of earlier, more extensive land. The different centres of diversity in the different groups are suggested to derive from vicariant locations of early (Mesozoic – early Cainozoic) diversity rather than from different means of dispersal or other aspects of ecology.
Estimated migration rates under scenarios of global climate change
Authors: Malcolm Jay R. , Markham Adam , Neilson Ronald P. , Garaci Michael 
Published: March 2003

AimGreenhouse‐induced warming and resulting shifts in climatic zones may exceed the migration capabilities of some species. We used fourteen combinations of General Circulation Models (GCMs) and Global Vegetation Models (GVMs) to investigate possible migration rates required under CO2‐doubled climatic forcing.LocationGlobal.MethodsMigration distances were calculated between grid cells of future biome type x and nearest same‐biome‐type cells in the current climate. In `base‐case' calculations, we assumed that 2 × CO2 climate forcing would occur in 100 years, we used ten biome types and we measured migration distances as straight‐line distances ignoring water barriers and human development. In sensitivity analyses, we investigated different time periods of 2 × CO2 climate forcing, more narrowly defined biomes and barriers because of water bodies and human development.ResultsIn the base‐case calculations, average migration rates varied significantly according to the GVM used (BIOME3 vs. MAPSS), the age of the GCM (older‐ vs. newer‐generation GCMs), and whether or not GCMs included sulphate cooling or CO2 fertilization effects. However, high migration rates (≥ 1000 m year−1) were relatively common in all models, consisting on average of 17% grid cells for BIOME3 and 21% for MAPSS. Migration rates were much higher in boreal and temperate biomes than in tropical biomes. Doubling of the time period of 2 × CO2 forcing reduced these areas of high migration rates to c. 12% of grid cells for both BIOME3 and MAPSS. However, to obtain migration rates in the Boreal biome that were similar in magnitude to those observed for spruce when it followed the retreating North American Glacier, a radical increase in the period of warming was required, from 100 to >1000 years. A reduction in biome area by an order of magnitude increased migration rates by one to three orders of magnitude, depending on the GVM. Large water bodies and human development had regionally important effects in increasing migration rates.Main conclusionsIn conclusion, evidence from coupled GCMs and GVMs suggests that global warming may require migration rates much faster than those observed during post‐glacial times and hence has the potential to reduce biodiversity by selecting for highly mobile and opportunistic species. Several poorly understood factors that are expected to influence the magnitude of any such reduction are discussed, including intrinsic migrational capabilities, barriers to migration, the role of outlier populations in increasing migration rates, the role of climate in setting range limits and variation in species range sizes.