bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Nitric Oxide Synthase Genes in Cluster Headache
Authors: Sjöstrand C , Modin H , Masterman T , Ekbom K , Waldenlind E , Hillert J
Published: March 2003

The aetiology of cluster headache is still not yet completely understood, but the potential relevance of genetic factors has been recognized during recent years. Nitric oxide (NO) plays a critical role in the regulation of vasodilation, neurotransmission, inflammation and many other events throughout the body. NO also appears to be an important mediator of vascular headache pathophysiology. In this study we have performed an association analysis of five polymorphic micro-satellite markers in the three different NO synthase (NOS) genes; nNOS (NOS1), iNOS (NOS2A) and eNOS (NOS3). Ninety-one cluster headache patients diagnosed according to International Headache Society criteria and 111 matched controls were studied. Phenotype and allele frequencies were similarly distributed in patients and controls except for an iNOS (NOS2A) pentanucleotide repeat allele which was significantly more common in controls. We observed a higher phenotype frequency of this allele in our control group compared with rates in control groups of other studies, whereas the frequency in our patients was similar to that in controls from previous reports. Thus, we conclude that it is unlikely that genetic variations within the NOS genes contribute greatly to cluster headache susceptibility.
‘Side Locked’ Migraine and Trigeminal Autonomic Cephalgias: Evidence for Clinical Overlap
Authors: Kaup AO , Mathew NT , Levyman C , Kailasam J , Meadors LA , Villarreal SS
Published: March 2003

This paper will discuss evidence which supports a link between ‘side locked’ migraine (SLM) and the trigeminal autonomic cephalgias (TACs). Recent papers brought strictly unilateral primary headaches into focus, proposing new classification and discussing pathophysiological mechanisms. We reviewed those proposals and present evidence that SLM falls in between the well-defined TACs and side shifting migraine (SSM). It is difficult to differentiate SLM from the recently proposed headache subtype called hemicrania generis incerti (i.e. hemicrania continua unresponsive to indomethacin). We also present cases that may exemplify the considerations made in the paper.
Women superintendents: the contribution of Margaret MacDowall and other women managers of mental deficiency institutions in England
Authors: Stevens Andy R. A.
Published: March 2003

The present paper explores gender differences in the management of mental deficiency institutions. It suggests that women played a particularly significant part in the management of some of the earliest institutions, and had a significant influence from the nineteenth century until well into the twentieth century. In addition, this study addresses the particular contribution of Miss S. Margaret MacDowall (1862–1930). Miss MacDowall's work demonstrates that teaching regimes and conditions in some types of smaller institutions run by women compare favourably to larger institutions run by men. The present paper further suggests that small institutions run by women during the Mental Deficiency Acts are worthy of more detailed study because these provide a continuity between nineteenth‐century pedagogic traditions and modern forms of community‐based residential care, and can offer useful ideas for developing residential care in the future.
Helping adults with a learning disability keep safe in the local community: report of a group design, development and evaluation
Authors: Long Karen , Holmes Nan
Published: March 2003

The present paper describes the design, delivery and evaluation of a Keeping Safe Group for adults with a learning disability. The group was designed to provide participants with information on keeping safe in the local community by avoiding potentially dangerous situations. The effectiveness of the group structure and format was evaluated during three pilot Keeping Safe Groups using an 18‐item test of knowledge administered before and after group attendance, and at follow‐up 4–6 months later. The results indicate that the Keeping Safe Group sessions provided an effective method for teaching participants the knowledge necessary to ensure that they kept themselves as safe as possible in the local community. The knowledge gained was maintained 4–6 months after the group finished. There were no gender variations or differences in the amount of knowledge learned during the three separate groups. Possible directions for future research are highlighted.
Achieving best evidence from witnesses with learning disabilities: new guidance
Authors: Cooke Pamela , Davies Graham
Published: March 2003

The new legislation contained within the UK Youth Justice and Criminal Evidence Act 1999, which comes into force in 2001, offers ‘special measures’ to enable vulnerable witnesses to give improved evidence in court. The present paper examines these measures and considers the guidelines which have been prepared to implement the legislation. The Guidance, currently contained within a Home Office Consultation Paper, Achieving Best Evidence in Criminal Proceedings: Guidance for Vulnerable or Intimidated Witnesses, including Children, emphasizes the need for early identification of witnesses with learning disabilities, and offers suggestions regarding identification and the type of support which should be offered in terms of attitude, conditions, practice and language.
Difference and choice: exploring prenatal testing and the use of genetic information with people with learning difficulties
Authors: Ward Linda , Howarth Joyce , Rodgers Jackie
Published: March 2003

Developments in genetics have huge implications for disabled people (including people with learning difficulties) and their families. On the positive side, there is the potential for greater understanding of – and ultimately, perhaps, treatments for – serious conditions like cystic fibrosis and sickle cell anaemia, but there are also concerns about the negative implications, including the potential for discrimination in insurance, employment and even life itself. Yet, the voices of those most affected by these developments – people with learning difficulties and their families, and disabled people generally – have been conspicuously absent from these debates. The present article describes two workshops that explained the use of prenatal testing and genetic information to inform choices in pregnancy to people with learning difficulties, and then explored the issues with them and the contribution subsequently made by these people to a national conference on this subject. Methods for explaining the complex issues involved in an accessible way and exploring them in a supportive environment are described along with the views of people with learning difficulties on these issues.
‘I might not know what you know but it doesn’t mean you can be awful to me'
Authors: Johnson Alex , Mason Heidi , Withers Paul
Published: March 2003

The case highlights the importance of providing a safe environment for individuals with learning disabilities to talk about their experiences and, particularly, their perspective on living with their learning disabilities. In particular, the case examines the experiences of a young lady who engaged in therapy, employing cognitive behavioural principles, in an attempt to address her negative self‐evaluation and understanding of the terms, learning disability and mental handicap.
Hydrothermal fluid flow models of stratiform ore genesis in the McArthur Basin, Northern Territory, Australia
Authors: Garven G. , Bull S. W. , Large R. R.
Published: March 2003

This paper explores the role of basin‐scale fluid migration in stratiform Pb–Zn ore formation in the southern McArthur Basin, Australia. Mathematical models are presented for coupled brine migration and heat transport in the basin. The models account for: (i) topographically driven flow (forced convection) during periods when parts of the McArthur Basin were subaerial and elevated above the central Batten Fault Zone; (ii) density‐driven flow (free convection) during periods when the basin was mostly submarine; and (iii) transient flows associated with fault rupture during periods of transpression. These hydrologic models help to compare and contrast a variety of hypotheses concerning deep fluid migration and the origin of base metal ores in the McArthur Basin. The numerical results exhibit a strong structural control on fluid flow caused by the north‐trending fault systems that characterize the Batten Fault Zone. As a result, fluids descend to depths of a few kilometers along the western side, migrate laterally to the east through the clastic and volcanic aquifers of the upper Tawallah and lowest McArthur Groups, and then ascend along the eastern side of the fault zone. This recharge–discharge pattern dominates all of the hydrogeologic models. The basin‐wide flow pattern suggests that Na–Ca–Cl brines acquired base metals in the deepest levels of the basin stratigraphy as the fluids migrated eastwards through the aquifer system. Upward flow was relatively rapid along the Emu Fault Zone, so much so that fluid temperatures likely approached 130°C in the muddy sediments near the sea floor due to upward flow and venting at the HYC (‘Here’s Your Chance'). Transient pulses of flow characterized periods of transpressional stress and subsequent faulting may have punctuated the basin history. Large‐scale free convection, however, characterized notably long periods of diagenesis and ore mineralization during the Proterozoic in the McArthur Basin.
Transfer of hydrocarbons from natural seeps to the water column and atmosphere
Authors: MacDonald I. R. , Leifer I. , Sassen R. , Stine P. , Mitchell R. , Guinasso N.
Published: March 2003

Results from surface geochemical prospecting, seismic exploration and satellite remote sensing have documented oil and gas seeps in marine basins around the world. Seeps are a dynamic component of the carbon cycle and can be important indicators for economically significant hydrocarbon deposits. The northern Gulf of Mexico contains hundreds of active seeps that can be studied experimentally with the use of submarines and Remotely Operated Vehicles (ROV). Hydrocarbon flux through surface sediments profoundly alters benthic ecology and seafloor geology at seeps. In water depths of 500–2000 m, rapid gas flux results in shallow, metastable deposits of gas hydrate, which reduce sediment porosity and affect seepage rates. This paper details the processes that occur during the final, brief transition — as oil and gas escape from the seafloor, rise through the water and dissolve, are consumed by microbial processes, or disperse into the atmosphere. The geology of the upper sediment column determines whether discharge is rapid and episodic, as occurs in mud volcanoes, or more gradual and steady, as occurs where the seep orifice is plugged with gas hydrate. In both cases, seep oil and gas appear to rise through the water in close proximity instead of separating. Chemical alteration of the oil is relatively minor during transit through the water column, but once at the sea surface its more volatile components rapidly evaporate. Gas bubbles rapidly dissolve as they rise, although observations suggest that oil coatings on the bubbles inhibit dissolution. At the sea surface, the floating oil forms slicks, detectable by remote sensing, whose origins are laterally within ∼1000 m of the seafloor vent. This contradicts the much larger distance predicted if oil drops rise through a 500 m water column at an expected rate of ∼0.01 m s−1 while subjected to lateral currents of ∼0.2 m s−1 or greater. It indicates that oil rises with the gas bubbles at speeds of ∼0.15 m s−1 all the way to the surface.
Geochemistry of the Bagnères‐de‐Bigorre thermal waters from the North Pyrenean Zone (France)
Authors: Levet S. , Toutain J. P. , Munoz M. , Berger G. , Negrel P. , Jendrzejewski N. , Agrinier P. , Sortino F.
Published: March 2003

Thermal springs are poorly known in the sedimentary sites of the Pyrenees. In this paper, we describe the ‘Bagnères‐de‐Bigorre’ springs which occur in a remarkably active seismotectonic context. A chemical and isotopic study of 15 spring waters (both cold and thermal, ranging in temperature from 7.0 to 49.9°C), and continuous monitoring of a single spring allow us to characterise water–rock interactions, fluids paths and mixing processes.

Three groups of waters are distinguished: (I) SO42+–Ca2+–Cl– thermal waters (II) SO42+–Cl––Ca2+ thermal waters and (III) HCO3––Ca2+ cold shallow waters. Their characteristics suggest interactions with Mesozoic evaporite and carbonate formations. O and D isotopes from thermal waters indicate a local meteoric origin of Atlantic signature and a recharge elevation of 800 to 1000 m, which corresponds to a single feeding area. Their δ13C values (−2.8 to −9.6‰) are consistent with carbonate dissolution, slight fractionation and a surficial organic input leading to δ13C depletion. Sr isotopes (0.70751 to 0.70777), Na+/Cl– and (Ca2+ + Mg2+)/SO42– ratios as well as thermodynamic calculations show that the dissolution of anhydrite and halite‐bearing Triassic layers control the chemical composition of group‐I and ‐II waters.

The contrasting trends of cation/Cl– ratios and TDS of waters from groups I and II suggest the existence of two different circulation paths at depth as well as dilution with surficial waters similar to group III. Calculated mixing proportions show that three waters from group I are diluted from 17 to 66%, whereas all waters from group II are mixed.

The aquifer temperature is estimated to be in the range 55–64°C using the retrograde and prograde solubilities of anhydrite and chalcedony, respectively. Accordingly, the mean depth of the reservoir is around 1.7 km, which allows us to constrain the depth of the Triassic layer.
Gas breakthrough experiments on fine‐grained sedimentary rocks
Authors: Hildenbrand A. , Schlömer S. , Krooss B. M.
Published: March 2003

The capillary sealing efficiency of fine‐grained sedimentary rocks has been investigated by gas breakthrough experiments on fully water saturated claystones and siltstones (Boom Clay from Belgium, Opalinus Clay from Switzerland and Tertiary mudstone from offshore Norway) of different lithological compositions. Sand contents of the samples were consistently below 12%, major clay minerals were illite and smectite. Porosities determined by mercury injection lay between 10 and 30% while specific surface areas determined by nitrogen adsorption (BET method) ranged from 20 to 48 m2 g − 1. Total organic carbon contents were below 2%.

Prior to the gas breakthrough experiments the absolute (single phase) permeability (kabs) of the samples was determined by steady state flow tests with water or NaCl brine. The kabs values ranged between 3 and 550 nDarcy (3 × 10−21 and 5.5 × 10−19 m2). The maximum effective permeability to the gas‐phase (keff) measured after gas breakthrough on initially water‐saturated samples extended from 0.01 nDarcy (1 × 10−23 m2) up to 1100 nDarcy (1.1 × 10−18 m2). The residual differential pressures after re‐imbibition of the water phase, referred to as the ‘minimum capillary displacement pressures’ (Pd), ranged from 0.06 to 6.7 MPa. During the re‐imbibition process the effective permeability to the gas phase decreases with decreasing differential pressure. The recorded permeability/pressure data were used to derive the pore size distribution (mostly between 8 and 60 nm) and the transport porosity of the conducting pore system (10‐5–10‐2%).

Correlations could be established between (i) absolute permeability coefficients and the maximum effective permeability coefficients and (ii) effective or absolute permeability coefficients and capillary sealing efficiency. No correlation was found between the capillary displacement pressures determined from gas breakthrough experiments and those derived theoretically by mercury injection.
The origins of salinity in metamorphic fluids
Authors: Yardley B. W. D. , Graham J. T.
Published: March 2003

Evaluation of data on formation waters and metamorphic fluids sampled by drilling or preserved in fluid inclusions reveals little correlation between fluid salinity and metamorphic grade, but a strong link to original sedimentary setting. Sediments and metasediments deposited originally in shallow marine environments can contain fluids with a very wide range of salinities, but they are commonly near twice seawater salinity or higher. With increasing metamorphic grade, a very wide range of salinities may develop, with the highest levels tracking halite saturation. Oceanic and accretionary prism sequences yield low‐salinity fluids, close to seawater values, almost irrespective of metamorphic grade until extreme conditions are reached where removal of water may increase fluid salinity. The salinities of metamorphic fluids exert a fundamental control on both fluid phase equilibria and metal‐transporting capability, and appear, to a large degree, to reflect the original presence or absence of highly saline formation waters and/or evaporites in the initial sedimentary sequence.
Re‐equilibration of fluid inclusions in diagenetic‐anchizonal rocks of the Ciñera‐Matallana coal basin (NW Spain)
Authors: Ayllón F. , Bakker R. J. , Warr L. N.
Published: March 2003

Thermally re‐equilibrated fluid inclusions are reported in natural fissure quartz (qtz1) from polymineralic veins in the diagenetic‐anchizonal clastic sedimentary rocks of the Ciñera‐Matallana coal basin (Variscan, NW Spain). Euhedral quartz formed during early fissure opening from an immiscible fluid mixture composed of a low salinity aqueous solution and a CH4‐rich vapour phase, at temperatures of about 110–120°C and pressures ranging from 15 to 56 MPa. Five textural types of re‐equilibration are recognised in progressive order of inclusion modification: scalloped, hairy, annular‐ring shaped, haloes and decrepitation clusters. These textures resulted from a combination of brittle fracturing and dissolution and re‐precipitation of quartz, with preferential loss of water. The thermal peak was short‐lived, but was high enough to induce extensive decrepitation of fluid inclusions in vein quartz throughout the entire basin. Enhanced temperatures can be related to the intrusion of diorites in the basin. Careful analysis of textural features in fluid inclusions from diagenetic and very low‐grade metamorphism environments constitutes a useful tool for recording basin thermal history.
The origin of deep subsurface microbial communities in the Witwatersrand Basin, South Africa as deduced from apatite fission track analyses
Authors: Omar G. I. , Onstott T. C. , Hoek J.
Published: March 2003

The first fission track analyses of detrital apatite grains from the subsurface of the Kaapvaal Craton were utilized to delineate the thermal history for the northern margin of the Witwatersrand Basin, South Africa, where evidence for subsurface thermophilic and hyperthermophilic microorganisms have been discovered. Fission track apatite ages for core samples ranged from 21 to 422 Ma. The trend of decreasing age with increasing depth parallels a trend previously reported for fission track data from surface samples collected from the higher altitude centre and lower altitude margins of the Kaapvaal Craton, South Africa. These new fission track ages are older than the surface samples of equivalent elevation, indicating that the uplift history and/or the geothermal gradient of the centre of the Kaapvaal Craton is distinct from that of its margins. Modelling of one sample collected from a depth of 3.7 km records cooling from 120°C at 75 Ma at a rate of approximately 1.4°C m.y.−1 and reaching present day temperatures at 30 Ma. This modelling result when compared to other apatite fission track dates indicate that this cooling trend followed a 90‐Ma thermotectonic event. The fission track data also indicate that heated fluid migration, which is observed today in this region of the Witwatersrand Basin, was also active in the past in order to explain the greater palaeogeothermal gradient (18 versus 8°C km−1). The fission track results suggest that at approximately 70 Ma only hyperthermophilic microorganisms could have existed at palaeodepths >3.2 km depth in the Witwatersrand Basin, and that the current meso/thermophilic microbial communities living at or beneath the present depth of 1.7 km in the Witwatersrand Basin must have migrated to their current location since 70 Ma. Any hyperthermophilic microorganisms found at the present depths 1.2–3.7 km could be descendents of subsurface hyperthermophiles that colonized the crust since the early Mesozoic to Palaeozoic eras.
The nutritional content of male prisoners' diet in the UK
Authors: Edwards John S. A. , Edwards Audrey , Reeve William G.
Published: March 2003

The Prison Catering Service has changed from a Ration Scale to a pre‐select menu system as the basis for providing prisoners' meals. The purpose of this research was to ascertain how this may have affected male prisoners' nutritional intake. Using a modified visual estimation technique, the dietary intake of 506 prisoners (mean age 35 years, height 1.77 m and weight 78.03 kg) in eight prisons was estimated for a 24‐h period. Results show that overall, the mean nutrient intake from food provided by HM Prisons (2561 kcal; 10.77 MJ) fell within current recommendations. However, in four prisons, energy intake was below the recommendations as were a small number of micronutrients (vitamin A, vitamin B2, vitamin C and calcium, one prison each; and vitamin D, in all prisons) from the food provided. The mean percentage of energy provided from total fat (36%) was just in excess of the recommendation of 35% and similar to the National average. There is little evidence to suggest that the ‘new’ system has any detrimental effects on prisoners' nutritional intake.
Restaurants and venison marketing: a South African experience
Authors: Radder Laetitia
Published: March 2003

Wild deer, antelope and other exotic animals have been hunted and their meat consumed for centuries. Although the game industry is the fastest growing agricultural industry in South Africa, the sale of venison constitutes a mere 2% of the estimated annual gross income of the wildlife industry. This is surprising, since, apart from its nutritional value, South African venison is free of diseases and originates from animals in their natural habitat, without human intervention in genetic selection, the use of growth hormones, insecticides, or pesticides. The perceived prejudice of South African consumers against venison could stem from bad taste experiences as a result of ignorance concerning the meat's preparation. The question arises whether away‐from‐home consumption in restaurants, hotels and coffee shops could play a role in introducing consumers to the taste of well‐prepared venison. This exploratory study investigates the supply of and demand for venison at restaurants in the metropolitan areas of the Eastern Cape, the top hunting region of South Africa. It also deals with the management of menus and restaurant owners’ perceptions about consumers’ interest in venison, since it is argued that away‐from‐home consumption can only play a role if restaurant owners or chefs include venison on their menus.
Interference interactions, co‐existence and conservation of mammalian carnivores
Authors: Linnell John D. C. , Strand Olav
Published: March 2003

Abstract. The shift in emphasis from single species to ecosystem conservation is revealing how community interactions can potentially influence single species viability and conservation. Although there is much theory and empirical data concerning the dynamic consequences of exploitative interactions, there is still a very poor understanding of the effects of interference interactions. Recent studies, as shown in this review, have documented widespread effects of such interactions among mammalian carnivores. Harassment, loss of kills and intraguild predation have been documented in a wide range of species. The demonstrated effects also include avoidance of larger carnivores in both time and space and reductions in one species density or even total exclusion from certain habitats or regions. Our review of the literature thus provides a range of empirical examples that together demonstrate that these interactions have very important implications on carnivore demography. We believe that the effects of interference might differ strongly from the effects of exploitative competition. This is because interference might have the potential to affect population growth in an inverse density‐dependent manner and thereby also reduce population growth at low densities, therefore increasing extinction probabilities. These factors need to be considered when planning future multi‐species conservation. Further research into the temporal and spatial aspects of co‐existence are required if diverse guilds and communities are to be conserved.
Naturalization and invasion of alien plants: concepts and definitions
Authors: Richardson David M. , Pyšek Petr , Rejmánek Marcel , Barbour Michael G. , Panetta F. Dane , West Carol J.
Published: March 2003

Abstract.  Much confusion exists in the English‐language literature on plant invasions concerning the terms ‘naturalized’ and ‘invasive’ and their associated concepts. Several authors have used these terms in proposing schemes for conceptualizing the sequence of events from introduction to invasion, but often imprecisely, erroneously or in contradictory ways. This greatly complicates the formulation of robust generalizations in invasion ecology.

Based on an extensive and critical survey of the literature we defined a minimum set of key terms related to a graphic scheme which conceptualizes the naturalization/invasion process. Introduction means that the plant (or its propagule) has been transported by humans across a major geographical barrier. Naturalization starts when abiotic and biotic barriers to survival are surmounted and when various barriers to regular reproduction are overcome. Invasion further requires that introduced plants produce reproductive offspring in areas distant from sites of introduction (approximate scales: > 100 m over < 50 years for taxa spreading by seeds and other propagules; > 6 m/3 years for taxa spreading by roots, rhizomes, stolons or creeping stems). Taxa that can cope with the abiotic environment and biota in the general area may invade disturbed, seminatural communities. Invasion of successionally mature, undisturbed communities usually requires that the alien taxon overcomes a different category of barriers.

We propose that the term ‘invasive’ should be used without any inference to environmental or economic impact. Terms like ‘pests’ and ‘weeds’ are suitable labels for the 50–80% of invaders that have harmful effects. About 10% of invasive plants that change the character, condition, form, or nature of ecosystems over substantial areas may be termed ‘transformers’.
Feeding and breeding across host plants within a locality by the widespread thrips Frankliniella schultzei, and the invasive potential of polyphagous herbivores
Authors: Milne M. , Walter G. H.
Published: March 2003

Abstract. Polyphagous insect herbivores could be expected to perform relatively well in new areas because of their ability to exploit alternative resources. We investigated relative abundance patterns of the polyphagous thrips species Frankliniella schultzei, which is characteristically found on plants from many different families, to establish the role of different host plant species in a single locality where the species is not indigenous (Brisbane, south‐eastern Queensland, Australia). F. schultzei females and larvae were always present in flowers (where oviposition takes place) and never on leaves of the eight plant species that we surveyed regularly over one year. They were present in flowers of Malvaviscus arboreus in much higher densities than for any other host. F. schultzei females were more fecund and larvae developed faster on floral tissue diets of M. arboreus than on those of other hosts. M. arboreus is therefore regarded as the ‘primary’ host plant of F. schultzei in the locality that we investigated. The other species are regarded as ‘minor’ hosts. Available evidence indicates a common geographical origin of F. schultzei and M. arboreus. F. schultzei may therefore be primarily adapted to M. arboreus. The flowers of the minor species on which F. schultzei is also found may coincidentally share some features of the primary host. Adult thrips may therefore accumulate on minor hosts and breed there, but to a lesser extent than on the primary host. The general implications for investigating polyphagous host relationships and interpreting the ecology of these species as generalist invaders are spelt out.
A PCA‐based modelling technique for predicting environmental suitability for organisms from presence records
Authors: Robertson M. P. , Caithness N. , Villet M. H.
Published: March 2003

We present a correlative modelling technique that uses locality records (associated with species presence) and a set of predictor variables to produce a statistically justifiable probability response surface for a target species. The probability response surface indicates the suitability of each grid cell in a map for the target species in terms of the suite of predictor variables. The technique constructs a hyperspace for the target species using principal component axes derived from a principal components analysis performed on a training dataset. The training dataset comprises the values of the predictor variables associated with the localities where the species has been recorded as present. The origin of this hyperspace is taken to characterize the centre of the niche of the organism. All the localities (grid‐cells) in the map region are then fitted into this hyperspace using the values of the predictor variables at these localities (the prediction dataset). The Euclidean distance from any locality to the origin of the hyperspace gives a measure of the ‘centrality’ of that locality in the hyperspace. These distances are used to derive probability values for each grid cell in the map region. The modelling technique was applied to bioclimatic data to predict bioclimatic suitability for three alien invasive plant species (Lantana camara L., Ricinus communis L. and Solanum mauritianum Scop.) in South Africa, Lesotho and Swaziland. The models were tested against independent test records by calculating area under the curve (AUC) values of receiver operator characteristic (ROC) curves and kappa statistics. There was good agreement between the models and the independent test records. The pre‐processing of climatic variable data to reduce the deleterious effects of multicollinearity, and the use of stopping rules to prevent overfitting of the models are important aspects of the modelling process.
Diversity of zonal páramo plant communities in Ecuador
Authors: Sklenár Petr , Ramsay Paul M.
Published: March 2003

Patterns of vascular plant species diversity in high‐altitude Ecuadorian ecosystems (‘páramos’) are examined. Data from two independent surveys were used: the first from 12 different locations and 192 samples, the other from 18 locations and 243 samples. These surveys included 348 and 284 species, respectively. The data confirmed the occurrence of two main zones in terms of vascular plant species diversity. The grass páramo and superpáramo were distinguished by differences in plant cover, species richness, α‐diversity and β‐diversity. The transition between these two zones begins at around 4000 m. Grass páramo samples comprised more species but the strong dominance of tussock grasses resulted in low equitability compared with the superpáramo, where safe sites for plant survival are limited and the environment does not permit continuous grass cover. Turnover of species across the altitudinal gradient is higher in the grass páramo than in the superpáramo. This is due largely to agricultural fires at lower altitudes, which create a fine‐scale mosaic of burned patches that enhances variability at this scale. Despite the loss of equitability, intermediate levels of fire disturbance appear to promote species richness within the samples. It is suggested that the complex patterns of páramo diversity in the Ecuadorian Andes are largely the outcome of three interrelated factors: altitude, disturbance and the availability of safe sites at the highest altitudes.
A model for range expansion of an introduced species: the common waxbillEstrilda astrildin Portugal
Authors: Silva Tiago , Reino Luís M. , Borralho Rui
Published: March 2003

Abstract.The common waxbillEstrilda astrildwas first introduced to Portugal from Africa in 1964, and has spread across much of the country and into Spain. We modelled the expansion of the common waxbill on a 20 × 20 km UTM grid in 4‐year periods from 1964 to 1999. The time variation of the square root of the occupied area shows that this expansion process is stabilizing in Portugal, and reasons for this are discussed. Several methods used to model biological expansions are not appropriate for the present case, because little quantitative data are available on the species ecology and because this expansion has been spatially heterogeneous. Instead, colonization on a grid was modelled as a function of several biophysical and spatio‐temporal variables through the fitting of a multivariate autologistic equation. This approach allows examination of the underlying factors affecting the colonization process. In the case of the common waxbill it was associated positively with its occurrence in adjacent cells, and affected negatively by altitude and higher levels of solar radiation.
Global amphibian declines: sorting the hypotheses
Authors: Collins James P. , Storfer Andrew
Published: March 2003

Abstract. Reports of malformed amphibians and global amphibian declines have led to public concern, particularly because amphibians are thought to be indicator species of overall environmental health. The topic also draws scientific attention because there is no obvious, simple answer to the question of what is causing amphibian declines? Complex interactions of several anthropogenic factors are probably at work, and understanding amphibian declines may thus serve as a model for understanding species declines in general. While we have fewer answers than we would like, there are six leading hypotheses that we sort into two classes. For class I hypotheses, alien species, over‐exploitation and land use change, we have a good understanding of the ecological mechanisms underlying declines; these causes have affected amphibian populations negatively for more than a century. However, the question remains as to whether the magnitude of these negative effects increased in the 1980s, as scientists began to notice a global decline of amphibians. Further, remedies for these problems are not simple. For class II hypotheses, global change (including UV radiation and global climate change), contaminants and emerging infectious diseases we have a poor, but improving understanding of how each might cause declines. Class II factors involve complex and subtle mechanistic underpinnings, with probable interactions among multiple ecological and evolutionary variables. They may also interact with class I hypotheses. Suspected mechanisms associated with class II hypotheses are relatively recent, dating from at least the middle of the 20th century. Did these causes act independently or in concert with pre‐existing negative forces of class I hypotheses to increase the rate of amphibian declines to a level that drew global attention? We need more studies that connect the suspected mechanisms underlying both classes of hypotheses with quantitative changes in amphibian population sizes and species numbers. An important step forward in this task is clarifying the hypotheses and conditions under which the various causes operate alone or together.
Nitric oxide donor FK409 and 8‐bromoguanosine‐cyclic monophosphate attenuate cardiac contractility assessed by Emax
Authors: Hiraga Hitoshi , Okubo Tomoyuki , Suto Naoyuki , Yamamoto Takeru , Yoshida Ikko Mario , Okumura Ken
Published: March 2003

FK409 decomposes and releases nitric oxide (NO) spontaneously when it is dissolved in phosphate buffer solution at 37 °C. With the use of this NO donor, the effect of exogenous NO on cardiac contractility was examined by assessing Emax. α‐chloralose‐anaesthetized dogs were instrumented for measurements of left ventricular (LV) pressure and volume and coronary blood flow (CBF) in the left anterior descending artery (LAD). FK409, 8‐bromoguanosine‐cyclic‐monophosphate (8‐Br‐cGMP) and papaverine were infused into the LAD, and Emax was determined by transient inferior vena cava occlusion when CBF was increased and reached its peak. Neither drug affected heart rate nor LV pressure just before the measurement of Emax. FK409 increased CBF and decreased Emax in a dose‐dependent manner. 8‐Br‐cGMP also increased CBF and decreased Emax in a dose‐dependent manner. Pretreating with propranolol did not affect the effects of FK4098‐Br‐cGMP on CBF and Emax. Papaverine increased mean CBF but did not affect Emax. In conclusion NO attenuates cardiac contractility in vivo, while increasing CBF. This effect seems to be mediated by cyclic‐guanosine monophosphate, a second messenger of NO.
Different types of antagonism by losartan and irbesartan on the effects of angiotensin II and its degradation products in rabbit arteries
Authors: Li Q , Pfaffendorf M , Van Zwieten P A
Published: March 2003

A previous study by our group has demonstrated that the selective AT1‐receptor antagonist losartan behaves as a noncompetitive antagonist in rabbit isolated renal artery (RA). In the present investigation, the influence of losartan and irbesartan on the contractile effects of angiotensin II (AII) and its degradation products angiotensin III (AIII) and angiotensin IV (AIV) was determined in the rabbit isolated RA and femoral artery (FA). The arteries were set up in organ chambers and changes in isometric force were recorded. In both rabbit isolated RA and FA preparations, AII, AIII and AIV elicited significant contractile responses with a similar efficacy. These effects were impaired by the presence of functional endothelium in RA preparations but not in FA preparations. In both preparations studied, the effects of AII, AIII and AIV were influenced neither by the aminopeptidase‐A and ‐M inhibitor amastatin (10 μM), nor by the aminopeptidase‐B and ‐M inhibitor bestatin (10 μM). In endothelium‐denuded FA preparations, preincubation with losartan (3–300 nM) antagonized AII‐, AIII‐ and AIV‐induced contractions in a competitive manner. However, in endothelium‐denuded RA preparations, losartan depressed the maximal contractile responses induced by AII but not those induced by AIII and AIV. In the same preparations, preincubation of another selective AT1‐receptor antagonist irbesartan (3–30 nM) concentration‐dependently shifted AII and AIII curves to the right in an insurmountable manner. The reduction of the maximal response of AII is more potent when compared to that of AIII (47.7 ± 1.51% vs. 66.7 ± 1.88%, percentage of the initial maximal response; P < 0.05; n=5). The selective AT2‐receptor antagonist PD123177 (1 μM) did not influence the responses to all three peptides in both RA and FA preparations. These heterogeneous antagonistic effects of the two AT1‐receptor antagonists studied with respect to the contractile actions of AII, AIII and AIV suggest the possible existence of multiple, functionally relevant AT1‐receptor subtypes in rabbit RA preparations.
Complement and its implications in cardiac ischemia/reperfusion: strategies to inhibit complement
Authors: Monsinjon Tiphaine , Richard Vincent , Fontaine Marc
Published: March 2003

Although reperfusion of the ischemic myocardium is an absolute necessity to salvage tissue from eventual death, it is also associated with pathologic changes that represent either an acceleration of processes initiated during ischemia or new pathophysiological changes that were initiated after reperfusion. This so‐called ‘reperfusion injury’ is accompanied by a marked inflammatory reaction, which contributes to tissue injury. In addition to the well known role of oxygen free radicals and white blood cells, activation of the complement system probably represents one of the major contributors of the inflammatory reaction upon reperfusion. The complement may be activated through three different pathways: the classical, the alternative, and the lectin pathway. During reperfusion, complement may be activated by exposure to intracellular components such as mitochondrial membranes or intermediate filaments. Two elements of the activated complement contribute directly or indirectly to damages: anaphylatoxins (C3a and C5a) and the membrane attack complex (MAC). C5a, the most potent chemotactic anaphylatoxin, may attract neutrophils to the site of inflammation, leading to superoxide production, while MAC is deposited over endothelial cells and smooth vessel cells, leading to cell injury.

Experimental evidence suggests that tissue salvage may be achieved by inhibition of the complement pathway. As the complement is composed of a cascade of proteins, it provides numerous sites for pharmacological interventions during acute myocardial infarction. Although various strategies aimed at modulating the complement system have been tested, the ideal approach probably consists of maintaining the activity of C3 (a central protein of the complement cascade) and inhibiting the later events implicated in ischemia/reperfusion and also in targeting inhibition in a tissue‐specific manner.
In vitro function of porcine carotid arteries preserved in UW, HTK and Celsior solutions
Authors: Abrahamse S.T.L. , Dinant S. , Pfaffendorf M. , Van Gulik T.M.
Published: March 2003

We compared the efficacy of histidine‐tryptophan‐ketoglutarate (HTK) and University of Wisconsin (UW) solution with Celsior solution using hypothermically‐preserved porcine carotid arteries and studied the importance of different components of these solutions by preserving carotid arteries in modified HTK solutions.

Excised carotid arteries were stored at 4 °C in 0.9% (w/v) NaCl, UW, HTK, Celsior, or a modified HTK solution for up to 14 days. Preservation‐induced changes in smooth muscle cell and endothelial cell function were determined using an organ bath for isometric tension recording.

Short‐term preservation (1–3 days) in UW, HTK and Celsior did not significantly alter contractile and relaxation responses of arterial segments when compared to freshly‐excised segments, but significantly impaired these responses in arterial segments stored in 0.9% (w/v) NaCl solution. Long‐term hypothermic preservation of arterial segments (7 and 14 days) in 0.9% (w/v) NaCl and HTK solution almost completely abolished all responses, but only slightly reduced the responses of arterial segments stored in UW solution. Intermediate results were obtained for Celsior. Modifying HTK by replacement of chloride for sulfate and phosphate resulted in improved contractile and relaxation responses after long‐term preservation.

With respect to smooth muscle and endothelial function, UW is superior to HTK and Celsior and the absence of chloride or presence of sulfate and phosphate plays a relevant role in this in vitro model of hypothermic preservation of porcine carotid arteries.
Unlicensed and off‐label uses of drugs in paediatrics: a review of the literature
Authors: Cuzzolin Laura , Zaccaron Ada , Fanos Vassilios
Published: March 2003

The off‐label and unlicensed use of drugs to treat children is a common practice that occurs either in hospital or in the community. This derives from the fact that research for establishing drug efficacy and safety in children has not been carried out due to ethical problems, logistical difficulties, financial and legal concerns. In this work we report the studies available in literature documenting the extent of drug use in the paediatric field outside the recommendations of the license. From our analysis, a widespread attitude to prescribe medicines to children outside their product license either in the hospitals or in the community is confirmed. This suggests an immediate action for a more rationale use of drugs in paediatrics, to avoid exposing children and infants to unnecessary risks, but also to avoid depriving them of potentially effective and sometimes life‐saving therapies.
Trimetazidine effect on phospholipid synthesis in ventricular myocytes: consequences in α‐adrenergic signaling
Authors: Tabbi‐Anneni Iméne , Lucien Arnaud , Grynberg Alain
Published: March 2003

The anti‐anginal drug trimetazidine (TMZ) has been shown to increase the synthesis of phospholipids in ventricular myocytes, including phosphatidyl‐inositol (PI). This study focused on the consequences of increasing PI metabolism on α‐adrenergic signaling pathway in cultured rat cardiomyocytes. In the cells treated with TMZ, the synthesis of PI from inositol was largely increased as compared with the control (+55% in 60 min). The stimulation of α‐adrenergic receptors by phenylephrine (PE) induced a dose‐dependent production of inositide phosphates (IPs) by phospholipase C (PLC) activation. However, the amount of available IPs was significantly lower in TMZ‐treated cells, in a dose‐dependant manner. This effect was observed in the presence and absence of the IP1‐phosphatase inhibitor LiCl. The in vitro determination of PLC activity revealed that this effect could not be attributed to the direct inhibition of the enzyme by TMZ. The TMZ‐induced reduction of IPs in the PE‐stimulated cardiomyocytes should be attributed to the increase of inositol recycling and incorporation in membrane structures, elicited by increased phospholipid synthesis. The consequences of this reduction in IPs availability were investigated on the cardiomyocyte hypertrophy induced by α‐adrenergic chronic stimulation. Acute stimulation with PE increased protein synthesis (+50%), but this increase was largely prevented by TMZ. In conclusion, TMZ reduces cell available IPs, by accelerating their recycling in membranes as PI. This effect results in a cytoprotection in the pathological process of hypertrophy elicited by chronic α‐adrenergic stimulation.
Determinants of respiratory system input impedance and bronchodilator response in healthy Finnish preschool children
Authors: Malmberg L. P. , Pelkonen A. , Poussa T. , Pohjanpalo A. , Haahtela T. , Turpeinen M.
Published: March 2003

In order to study the determinants of respiratory system impedance and bronchodilator response in preschool children, a sample (n=109) of healthy children (age 2·1–7·0 years) attending kindergarten was measured by using the impulse oscillometry. Their selection was based on a standardized questionnaire, negative skin prick test results and clinical examination, and sufficient cooperation. Triple measurements of respiratory resistance (Rrs) and reactance (Xrs) at 5, 10, 15 and 20 Hz, total respiratory impedance (Zrs), the resonance frequency (Fr) and the frequency dependence of resistance (dRrs/df) were performed, to determine individual mean values. Measurements were repeated after inhalation of 300 μg salbutamol (n=89) or placebo (n=19). At the baseline, Zrs and Rrs5‐20 showed negative, and Xrs5‐20, Fr and dRrs/df positive correlations with age, height and weight. However, logarithmic transformed height was the best independent variable for the regression equations of all the oscillometric variables. After inhalation of placebo, none of the oscillometric variables changed significantly. In the salbutamol group, the mean (SD) change in Rrs5 was −0·187 (0·124) kPa l–1 s–1 and –19·2 (10·2)%, corresponding to a lower reference limit of –36·9%. Both the within‐test and between‐test repeatabilities for the measurement of respiratory resistance were acceptable, for Rrs5 the coefficients of variation being 6·2 and 6·1%, respectively. As the overall success rate in our sample was high (89%), the forced oscillation technique seems to be a useful method in assessing respiratory function and bronchial lability in preschool children.