bluuebunny/crossref_metadata_2025 huggingface dataset:
New concepts in bilirubin encephalopathy
Authors: Ostrow J. D. , Pascolo L. , Shapiro S. M. , Tiribelli C.
Published: October 2003

Revised concepts of bilirubin encephalopathy have been revealed by studies of bilirubin toxicity in cultured CNS cells and in congenitally jaundiced Gunn rats. Bilirubin neurotoxicity is related to the unbound (free) fraction of unconjugated bilirubin (Bf), of which the dominant species at physiological pH is the protonated diacid, which can passively diffuse across cell membranes. As the binding affinity of plasma albumin for bilirubin decreases strikingly as albumin concentration increases, previously reported Bfvalues were underestimated.

Newer diagnostic tests can detect reversible neurotoxicity before permanent damage occurs from precipitation of bilirubin (kernicterus). Early toxicity can occur at Bfonly modestly above aqueous saturation and affects astrocytes and neurons, causing mitochondrial damage, resulting in impaired energy metabolism and apoptosis, plus cell‐membrane perturbation, which causes enzyme leakage and hampers transport of neurotransmitters.

The concentrations of unbound bilirubin in the cerebro‐spinal fluid and CNS cells are probably limited mainly by active export of bilirubin back into plasma, mediated by ABC transporters present in the brain capillary endothelium and choroid plexus epithelium. Intracellular bilirubin levels may be diminished also by oxidation, conjugation and binding to cytosolic proteins.

These new concepts may explain the varied susceptibility of neonates to develop encephalopathy at any given plasma bilirubin level and the selective distribution of CNS lesions in bilirubin encephalopathy. They also can suggest better strategies for predicting, preventing and treating this syndrome.
Four peptides decrease the number of human pancreatic adenocarcinoma cells
Authors: Vesely B. A. , McAfee Q. , Gower W. R. , Vesely D. L.
Published: October 2003

Background  Long‐acting natriuretic peptide, vessel dilator, kaliuretic peptide and atrial natriuretic peptide are four peptide hormones synthesized by the same gene. Their main known biologic properties are sodium and water excretion and blood pressure lowering in both animals and humans.

Methods and materials  These four peptide hormones, each at their 1‐µm concentrations, were evaluated for their ability to decrease the number and/or proliferation of human pancreatic adenocarcinoma cells in culture at 24, 48, 72 and 96 h.

Results  Vessel dilator, long‐acting natriuretic peptide, kaliuretic peptide and atrial natriuretic peptide decreased the number of human pancreatic adenocarcinoma cells in culture by 65% (P < 0·001), 47% (P < 0·01), 37% (P < 0·05) and 34% (P < 0·05), respectively, within 24 h. This decrease was sustained without any proliferation of the cancer cells occurring in the 3 days following this decrease in number. The mechanism of these peptide hormones’ decrease in cancer cell number and antiproliferative effects was a 83% (P < 0·001) or greater inhibition of DNA synthesis but not owing to enhanced apoptosis, i.e. programmed cell death. The two known mediators of these peptide hormones’ mechanism(s) of action, i.e. cyclic GMP and prostaglandin E2, inhibited DNA synthesis in these adenocarcinoma cells by 51% and 23%, respectively.

Conclusions  Four peptide hormones significantly decrease the number of pancreatic adenocarcinoma cells within 24 h and inhibit the proliferation of these cells for at least 96 h. Their mechanism of doing so is via inhibition of DNA synthesis mediated in part by cyclic GMP.
The disturbance of drilling mud on rock formation and a method for error elimination on acoustic log curves
Authors: Wei Changjiang , Li Jianjun , Liu Baohua , Xu Shizhe
Published: October 2003

Errors in acoustic logs have a significant influence on the assessment of formations, the description of oil deposits and modelling using synthetic seismograms. The elimination of these errors is a problem that many researchers have been trying to solve for many years. We derive theoretical formulae for calculating the radial depth of investigation of acoustic logging, and analyse the relationship between the error in acoustic interval transit time and the altered zone thickness. We explain in detail how mud affects the acoustic interval transit time. We also describe the variation of altered zone thickness with time and a method for calculating the altered zone thickness. Finally, we present a set of new methods that can be directly applied to correct the disturbing influence on acoustic curves. Our results are obtained based on the fact that acoustic velocities in the altered zone show a small lateral variation. Examples are given of analysing the acoustic log data, which are collected from a BS well at three different times. This paper is significant both for selection of the acoustic logging device with proper transmitter‐to‐receiver distance (spacing) and improvement of the device.
Seismic modelling study of a subglacial lake
Authors: Carcione José M. , Gei Davide
Published: October 2003

We characterize the seismic response of Lake Vostok, an Antarctic subglacial lake located at nearly 4 km depth below the ice sheet. This study is relevant for the determination of the location and morphology of subglacial lakes. The characterization requires the design of a methodology based on rock physics and numerical modelling of wave propagation. The methodology involves rock‐physics models of the shallow layer (firn), the ice sheet and the lake sediments, numerical simulation of synthetic seismograms, ray tracing, τ–p transforms, and AVA analysis, based on the theoretical reflection coefficients. The modelled reflection seismograms show a set of straight events (refractions through the firn and top‐ice layer) and the two reflection events associated with the top and bottom of the lake. Theoretical AVA analysis of these reflections indicates that, at near offsets, the PP‐wave anomaly is negative for the ice/water interface and constant for the water/sediment interface. This behaviour is shown by AVA analysis of the synthetic data set. This study shows that subglacial lakes can be identified by using seismic methods. Moreover, the methodology provides a tool for designing suitable seismic surveys.
Petrophysical inversion of AVA data
Authors: Mazzotti A. , Zamboni E.
Published: October 2003

We investigate the interactions between the elastic parameters,VP,VSand density, estimated by non‐linear inversion of AVA data, and the petrophysical parameters, depth (pressure), porosity, clay content and fluid saturation, of an actual gas‐bearing reservoir. In particular, we study how the ambiguous solutions derived from the non‐uniqueness of the seismic inversion affect the estimates of relevant rock properties. It results that the physically admissible values of the rock properties greatly reduce the range of possible seismic solutions and this range contains the actual values given by the well. By means of a statistical inversion, we analyse how approximatea prioriknowledge of the petrophysical properties and of their relationships with the seismic parameters can be of help in reducing the ambiguity of the inversion solutions and eventually in estimating the petrophysical properties of the specific target reservoir. This statistical inversion allows the determination of the most likely values of the sought rock properties along with their uncertainty ranges. The results show that the porosity is the best‐resolved rock property, with its most likely value closely approaching the actual value found by the well, even when we insert somewhat erroneousa prioriinformation. The hydrocarbon saturation is the second best‐resolved parameter, but its most likely value does not match the well data. The depth of the target interface is the least‐resolved parameter and its most likely value is strongly dependent ona prioriinformation. Although no general conclusions can be drawn from the results of this exercise, we envisage that the proposed AVA–petrophysical inversion and its possible extensions may be of use in reservoir characterization.
Joint AVO inversion, wavelet estimation and noise‐level estimation using a spatially coupled hierarchical Bayesian model
Authors: Buland Arild , Omre Henning
Published: October 2003

The main objective of the AVO inversion is to obtain posterior distributions for P‐wave velocity, S‐wave velocity and density from specified prior distributions, seismic data and well‐log data. The inversion problem also involves estimation of a seismic wavelet and the seismic‐noise level. The noise model is represented by a zero mean Gaussian distribution specified by a covariance matrix. A method for joint AVO inversion, wavelet estimation and estimation of the noise level is developed in a Bayesian framework. The stochastic model includes uncertainty of both the elastic parameters, the wavelet, and the seismic and well‐log data. The posterior distribution is explored by Markov‐chain Monte‐Carlo simulation using the Gibbs' sampler algorithm. The inversion algorithm has been tested on a seismic line from the Heidrun Field with two wells located on the line. The use of a coloured seismic‐noise model resulted in about 10% lower uncertainties for the P‐wave velocity, S‐wave velocity and density compared with a white‐noise model. The uncertainty of the estimated wavelet is low. In the Heidrun example, the effect of including uncertainty of the wavelet and the noise level was marginal with respect to the AVO inversion results.
Fracture characterization from walkaround VSPs
Authors: Horne Steve
Published: October 2003

A walkaround VSP is a novel acquisition geometry comprising multiple sources azimuthally distributed around a fixed multi‐component receiver at approximately the same offset. Such a configuration allows the robust measurement of fracture‐induced anisotropy by the analysis of certain seismic attributes with respect to azimuth.
Computations of secondary potential for 3D DC resistivity modelling using an incomplete Choleski conjugate‐gradient method
Authors: Wu Xiaoping , Xiao Yifei , Qi Cheng , Wang Tongtong
Published: October 2003

An accurate and efficient 3D finite‐difference (FD) forward algorithm for DC resistivity modelling is developed. In general, the most time‐consuming part of FD calculation is to solve large sets of linear equations: Ax=b, where A is a large sparse band symmetric matrix. The direct method using complete Choleski decomposition is quite slow and requires much more computer storage. We have introduced a row‐indexed sparse storage mode to store the coefficient matrix A and an incomplete Choleski conjugate‐gradient (ICCG) method to solve the large linear systems. By taking advantage of the matrix symmetry and sparsity, the ICCG method converges much more quickly and requires much less computer storage. It takes approximately 15 s on a 533 MHz Pentium computer for a grid with 46 020 nodes, which is approximately 700 times faster than the direct method and 2.5 times faster than the symmetric successive over‐relaxation (SSOR) conjugate‐gradient method. Compared with 3D finite‐element resistivity modelling with the improved ICCG solver, our algorithm is more efficient in terms of number of iterations and computer time. In addition, we solve for the secondary potential in 3D DC resistivity modelling by a simple manipulation of the FD equations. Two numerical examples of a two‐layered model and a vertical contact show that the method can achieve much higher accuracy than solving for the total potential directly with the same grid nodes. In addition, a 3D cubic body is simulated, for which the dipole–dipole apparent resistivities agree well with the results obtained with the finite‐element and integral‐equation methods. In conclusion, the combination of several techniques provides a rapid and accurate 3D FD forward modelling method which is fundamental to 3D resistivity inversion.
Velocity and attenuation in partially saturated rocks: poroelastic numerical experiments
Authors: Helle Hans B. , Pham Nam H. , Carcione José M.
Published: October 2003

We use a poroelastic modelling algorithm to compute numerical experiments on wave propagation in a rock sample with partial saturation using realistic fluid distribution patterns from tomography scans. Frequencies are in the range 10 to 500 kHz. The rock is a homogeneous isotropic sandstone partially filled with gas and water, which are defined by their characteristic values of viscosity, compressibility and density. We assume no mixing and that the two different pore‐fills occupy different macroscopic regions. The von Kármán self‐similar correlation function is used, employing different fractal parameters to model uniform and patchy fluid distributions, respectively, where effective saturation is varied in steps from full gas to full water saturation.

Without resorting to additional matrix–fluid interaction mechanisms, we are able to reproduce the main features of the variation in wave velocity and attenuation with effective saturation and frequency, as those of published laboratory experiments. Furthermore, the behaviour of the attenuation peaks versus water saturation and frequency is similar to that of White's model. The conversion of primary P‐wave energy into dissipating slow waves at the heterogeneities is shown to be the main mechanism for attenuating the primary wavefield. Fluid/gas patches are shown to affect attenuation more than equivalent patches in the permeability or solid‐grain properties.
Patterns in species richness and distribution of vascular epiphytes in Chiapas, Mexico
Authors: Wolf Jan H. D. , Alejandro Flamenco‐S
Published: October 2003

Aim  We aim to assess regional patterns in the distribution and species richness of vascular epiphytes with an emphasis on forests that differ in altitude and the amount of rainfall.

Location  Tropical America, in particularly the 75,000 km2 large state of Chiapas in southern Mexico at 14.5–18.0°N. Chiapas is diverse in habitats with forests from sea‐level to the tree‐line at c. 3800 m altitude and with annual amounts of rainfall ranging from 800 to over 5000 mm. It is also one of the botanical best‐explored regions in the tropics.

Methods  First we give an overview of epiphyte inventories to date. Such epiphyte surveys were mostly carried out on the basis of surface area or individual trees and we discuss their problematic comparison. Applying a different methodological approach, we then used 12,276 unique vascular epiphyte plant collections from Chiapas that are deposited in various botanical collections. The locality data were georeferenced and compiled in a relational data base that was analysed using a geographical information system. To compare the number of species between inventories that differed in the numbers of records, we estimated the total richness, SChao, at each.

Results  We recorded 1173 vascular epiphyte species in thirty‐nine families (twenty‐three angiosperms), comprising c. 14% of all confirmed plant species in the state. About half of all species were orchids (568). Ferns and bromeliads were the next species‐rich groups with 244 and 101 species, respectively. Most species were found in the Montane Rain Forest and in the Central Plateau. Trees of different forest formations, rainfall regimes, altitudes and physiographical regions supported a characteristic epiphyte flora.

Main conclusions  We were able to confirm the presumed presence of a belt of high diversity at mid‐elevations (500–2000 m) in neotropical mountains. In contrast to predictions, however, we observed a decrease in diversity when the annual amount of rainfall exceeded 2500 mm. The decrease is attributed to wind‐dispersed orchids, bromeliads and Pteridophyta that may find establishment problematical under frequent downpours. In the wet but seasonal forests in Chiapas, this decrease is not compensated by plants in the animal‐dispersed Araceae that are abundant elsewhere. We presume that in addition to the annual amount of rainfall, its distribution in time determines the composition of the epiphyte community.
Phytogeographical relations of the Andean dry valleys of Bolivia
Authors: López Ramiro Pablo
Published: October 2003

Aim The objective of this study is to examine the phytogeographical affinities of the Andean dry valleys of Bolivia in order to contribute to a better understanding of the Andean dry flora's distribution, origin and diversity. Particular emphasis is given to the analysis of the floristic connections of this flora with more austral parts of South America.

Location The dry valleys of Bolivia are located in the Andes of the southern half of the country, at elevations between 1300 and 3200 m.

Methods An extensive floristic list compiled by the author to evaluate plant diversity in these Andean regions was used as the base for this study. To accomplish this, all recorded genera and species were assigned, respectively, to 11 and 12 phytogeographical elements established previously by the author. Two phytogeographical spectra were thus obtained and analysed.

Results At the genus level, the Andean dry valleys of Bolivia are clearly dominated by genera that have widespread distributions (cosmoplitan and subtropical genera). Many of these reached the Andes from the lowland region of the Chaco. At species level, Andean elements constitute more than 60% of the species total, most of which are restricted to the central‐southern Andes. This suggests that Chaco‐related and Andean genera had considerable levels of speciation in these valleys. Many genera and more than half the species have their northernmost distribution in the dry valleys of Bolivia, thereby underlining strong relationships with central‐southern South America (mainly Argentina, Paraguay and southern Brazil). The data supports the belief of the existence, in central‐southern Peru, of a floristic disjunction in dry to arid environments that separates a tropical dry flora north of this limit from a dry subtropical/warm temperate flora south of it.

Main conclusions The Andean dry valleys of Bolivia are diverse plant communities with high levels of endemism (c. 18% of the species). The species of this region are more related to those present in central‐southern South America than to the flora of northern South America that ranges southwards to Peru. Many of the species have restricted distributions in the dry Andes of Bolivia and Argentina, and many genera of these dry valleys have their northernmost distribution in Bolivia/southern Peru, too. The data point to high levels of speciation also in the central Andes.
Correlates of geographic range size in New Zealand Chionochloa (Poaceae) species
Authors: Lloyd Kelvin M. , Bastow Wilson J. , Lee William G.
Published: October 2003

Aim To test for correlations between plant traits and geographic range size. Location: New Zealand.

Methods Trait data were derived from comparative experiments, in which plants were grown in pots or in a common garden, that tested for intrinsic differences among the species in traits relating to growth, reproduction and dispersal. Controlled experiments were used to test for differences in responses to drought and waterlogging stress. Geographic range size was measured as the number of 10 km grid squares in the New Zealand region containing at least one occurrence of the species.

Results Growth rate, dispersal capacity and environmental tolerance were all positively related to geographic range size. Geographically restricted species tended to have more variable flowering between years. Flowering intensity, reproductive allocation, seed set, diaspore size, and responses to single environmental factors were not related to geographic range size.

Main conclusions The differences between range‐restricted and widespread Chionochloa species appear to represent alternative strategies of coping with environmental change in a dynamic landscape. Range‐restricted species are specialized to temporally persistent habitats that are of limited geographic extent. As a consequence, they have evolved traits that conflict with persistence in widespread habitats. The implication for conservation management is that the conservation of rare plants will frequently depend on protection of their habitats. The widespread Chionochloa species possess traits that enable them to disperse to and occupy a greater range of habitats. These traits have allowed some of these species to expand their ranges following environmental changes that favoured an increase in grassland extent.
The northern limit of Pinus banksiana Lamb. in Canada: explaining the difference between the eastern and western distributions
Authors: Asselin Hugo , Payette Serge , Fortin Marie‐Josée , Vallée Sheila
Published: October 2003

Aim Present northern distribution limit of jack pine (Pinus banksiana Lamb.) follows the northern limit of continuous open boreal forest in western Canada, but not in eastern Canada where it is located further south. We tested the hypothesis that fire plays a more important role than climate in explaining the present position of the northern distribution limit of jack pine.

Location An experimental jack pine plantation was set up in 1992, c. 300 km north of the present distribution limit of the species, in the Boniface river area of northern Québec (57°43′ N, 76°05′ W).

Methods Climate and fire data were used to compare sites at and north of the present distribution limit of jack pine. In 2001, surviving individuals from the plantation were measured (total height, annual shoot elongation, basal diameter, and presence/absence of cones).

Results Climate data from the ten weather stations used in this study did not show major differences. The northern limit of jack pine distribution is closely associated with the occurrence of fires larger than 200 ha. Survival of the planted jack pines was 31%. About 25% of the surviving pines qualified as normal, single‐stem individuals; the others were slightly uprooted and/or showed marks of erosion or foraging. Cones were produced, although no viable seeds were found.

Main conclusions The low number of degree‐days above 5 °C at the plantation site could explain why the seeds were not viable. However, such climate conditions are not sufficient to prevent growth, as was shown by annual shoot elongation measurements. Most of the surviving jack pines from the Boniface river plantation are relatively healthy and follow a normal developmental programme. Low fire frequency and small fire size are amongst the main factors that prevented P. banksiana from migrating further north or east following deglaciation in northern Québec and Labrador.
Biogeography of temperate Australasian Polystichum ferns as inferred from chloroplast sequence and AFLP
Authors: Perrie Leon R. , Brownsey Patrick J. , Lockhart Peter J. , Brown Elizabeth A. , Large Mark F.
Published: October 2003

Aim and location New Zealand began to separate from Gondwana c. 85 Ma, and has been isolated from the nearest large landmass, Australia, by some 2000 km of the Tasman Sea since c. 60 Ma. Given New Zealand's long geographical isolation, there has been considerable interest in explaining the origins of its different biotic elements. Here we investigate the biogeography of the fern genus Polystichum from temperate Australasia. Six species are found in New Zealand, four in Australia, and two on Lord Howe Island.

Methods The evolutionary relationships between the twelve Polystichum species found in temperate Australasia were inferred from phylogenetic analyses of two molecular data sets: DNA sequence from the chloroplast rps4–trnS spacer locus; and AFLP DNA‐fingerprinting. The timing of the separation between Australian and New Zealand Polystichum was estimated by using the fossil record to temporally calibrate the rbcL sequence differentiation between representative species from these regions.

Results Species of Polystichum from New Zealand appear to comprise a monophyletic group. This suggests that Polystichum crossed the Tasman only once. Temporal calibration of the rbcL sequence differentiation between Australian and New Zealand Polystichum indicates that a vicariant explanation for their separation can be rejected in favour of trans‐oceanic dispersal.

Main conclusions The extant diversity within New Zealand Polystichum appears to have been derived from a single, trans‐oceanic dispersal event (within the last c. 20 Myr), followed by a relatively extensive in situ ecological radiation.
Phylogeny, biogeography and adaptive radiation of Pachycladon (Brassicaceae) in the mountains of South Island, New Zealand
Authors: Heenan P. B. , Mitchell A. D.
Published: October 2003

Aim To report analyses and propose hypotheses of adaptive radiation that explain distributional patterns of the alpine genus Pachycladon Hook.f. – a morphologically diverse genus from New Zealand closely related to Arabidopsis thaliana.

Location South Island, New Zealand.

Methods Morphological and nrDNA ITS sequence phylogenies were generated for Pachycladon. An analysis is presented of species distributional patterns and attributes.

Results Phylogenetic analyses of morphological characters and nrDNA ITS sequence data were found to be congruent in supporting three New Zealand clades for Pachycladon. Monophyletic groups identified within the genus are geographically distinct and are associated with different geological parent materials. Distribution maps, latitude and altitude range, and data on geological parent material are presented for the nine named and one unnamed species of Pachycladon from New Zealand.

Main conclusions (a) Panbiogeographic hypotheses accounting for the origin and present‐day distribution of Pachycladon in New Zealand are not supported.

 (b) Species diversity and distributions of Pachycladon are explained by a Late Tertiary–Quaternary adaptive radiation associated with increasing specialization to geological substrates. Pachycladon cheesemanii Heenan & A.D.Mitch. is morphologically similar to the closest overseas relatives. It is a geological generalist and has wide latitudinal and altitudinal ranges, and we suggest it resembles the ancestral form of the genus in New Zealand. Pachycladon novae‐zelandiae (Hook.f.) Hook.f. and P. wallii (Carse) Heenan & A.D.Mitch. are a southern South Island group that predominantly occurs on Haast Schist, are polycarpic, have lobed leaves, and lateral inflorescences. Pachycladon enysii (Cheeseman) Heenan & A.D.Mitch., P. fastigiata (Hook.f.) Heenan & A.D.Mitch., and P. stellata (Allan) Heenan & A.D.Mitch. are restricted to greywacke in the eastern South Island, and are facultatively monocarpic, have serrate leaves, and stout terminal inflorescenes.

 (c) Present distributions of Pachycladon species may relate to Pleistocene climate change. Pachycladon enysii reaches the highest altitude of New Zealand species of Pachycladon and is most common in the Southern Alps in Canterbury. We propose that this species survived on nunataks at the height of the last glaciation. In contrast, P. fastigiata grows at a lower altitude and is absent from the high mountains of the Southern Alps. We suggest it was extirpated from this area during the last glaciation.
Geographical sampling bias and its implications for conservation priorities in Africa
Authors: Reddy Sushma , Dávalos Liliana M.
Published: October 2003

Aim To design and apply statistical tests for measuring sampling bias in the raw data used to the determine priority areas for conservation, and to discuss their impact on conservation analyses for the region.

Location Sub‐Saharan Africa.

Methods An extensive data set comprising 78,083 vouchered locality records for 1068 passerine birds in sub‐Saharan Africa has been assembled. Using geographical information systems, we designed and applied two tests to determine if sampling of these taxa was biased. First, we detected possible biases because of accessibility by measuring the proximity of each record to cities, rivers and roads. Second, we quantified the intensity of sampling of each species inside and surrounding proposed conservation priority areas and compared it with sampling intensity in non‐priority areas. We applied statistical tests to determine if the distribution of these sampling records deviated significantly from random distributions.

Results The analyses show that the location and intensity of collecting have historically been heavily influenced by accessibility. Sampling localities show dense, significant aggregation around city limits, and along rivers and roads. When examining the collecting sites of each individual species, the pattern of sampling has been significantly concentrated within and immediately surrounding areas now designated as conservation priorities.

Main conclusions Assessment of patterns of species richness and endemicity at the scale useful for establishing conservation priorities, below the continental level, undoubtedly reflects biases in taxonomic sampling. This is especially problematic for priorities established using the criterion of complementarity because the estimated spatial costs of this approach are highly sensitive to sampling artefacts. Hence such conservation priorities should be interpreted with caution proportional to the bias found. We argue that conservation priority setting analyses require (1) statistical tests to detect these biases, and (2) data treatment to reflect species distribution rather than patterns of collecting effort.
Relationships of phytogeography and diversity of tropical tree species with limestone topography in southern Belize
Authors: Brewer Steven W. , Rejmánek Marcel , Webb Molly A. H. , Fine Paul V. A.
Published: October 2003

Aim The flora of northern Mesoamerica conventionally has been thought to be derived from taxa that emigrated from South America, but this view has recently been challenged as too simple. The dominance of limestone substrata in much of northern Mesoamerica, and its rarity in the rest of the continental Neotropics, may be one cause of the complexity of northern Mesoamerican floristics. Furthermore, northern Mesoamerica experiences longer and more intense seasonal drought than the rest of the continental Neotropics. As edaphic drought is accentuated with elevation on limestone soils, it may be expected that different topographic features have different phytogeographical affinities for seasonally drought‐prone areas of the Neotropics. The objective of this study was to test for effects of different topographic positions on the composition, phytogeography and diversity of tree species in a limestone area of Belize.

Location Maya Mountains, Belize, Mesoamerica.

Methods The diversity and local, regional, and hemispheric distributions of tree species on limestone valley floors, lower and upper slopes, and ridges were compared in southern Belize using 2 × 500 m transects as sample plots.

Results Stem density increased, and percentage of large trees decreased, significantly with elevation above the valley floors. The proportions of species that had widespread distributions decreased significantly with increasing elevation above the valley floors. The proportions of species having northern Mesoamerican distributions increased significantly with elevation above the valley floors. All of the forests generally had the strongest phytogeographical affinities for the Petén (Guatemala) and Mexico, but greater affinities for the Yucatán were observed with increasing elevation above the valley floors. Species with distributions including the Greater Antilles made up an increasingly significant element, in terms of species and numbers of stems, with increasing elevation above the floors of valleys. Valley floors and ridges had the highest percentages of species unique to their topographic positions, 61% and 39% of their species, respectively, and were very similar in diversity. Slope forests had the highest diversity of trees ≥ 5 cm d.b.h. and were transitional in composition among the topographic positions.

Main conclusions Despite relatively small changes in elevation, the composition, diversity and physical structure of the limestone forests changed significantly with topography. Such changes were presumably due to the greater edaphic drought experienced by these forests, and possibly due to lower levels of disturbance and differences in forest age, with increasing elevation above the floors of valleys.
Validity of a performance assessment of activities of daily living for people with developmental disabilities
Authors: Kottorp A. , Bernspång B. , Fisher A. G.
Published: October 2003

Background  Since clients with different types of developmental disabilities often experience difficulties in activities of daily living (ADL), it is critical that assessments of ADL are evaluated in order to ensure that one can make valid judgements based on the results of the appraisal. The purpose of the present study was to evaluate the validity of a specific performance assessment instrument, the Assessment of Motor and Process Skills (AMPS), when used by occupational therapists with clients with developmental disabilities. Unlike global ADL assessments, the AMPS is used not only to evaluate the level of ADL dependence, but also to estimate the quality of each specific action performed when a person is performing ADL tasks.

Methods  Data were gathered from 1724 participants with different developmental disabilities, including intellectual disability (ID), cerebral palsy and spina bifida. Many‐Facet Rasch (MFR) analysis was used to examine person‐response validity, and task and item scale validity.

Results  Goodness‐of‐fit statistics showed that the tasks and items had acceptable scale validity. The participants had acceptable person‐response validity on the ADL motor scale, but had slightly lower than expected levels of person‐response validity on the ADL process scale. The results indicate that clients with more severe forms of ID may have a higher proportion of different performance profiles in ADL than is expected by the MFR model of the AMPS. Since the proportion of participants who did not meet the criteria was only 3% lower than expected and in accordance with other studies, the difference may not be clinically meaningful. Otherwise, the results indicated that the AMPS is a valid tool when used with clients with developmental disabilities.

Conclusions  Further research is needed to evaluate the use of the AMPS in clinical assessment and intervention planning for this group of clients.
Nurse recognition of early deviation in development in home videos of infants with Rett disorder
Authors: Burford B. , Kerr A. M. , Macleod H. A.
Published: October 2003

Background  In the genetic Rett disorder (RD), infants make some progress then suffer a dramatic developmental regression, usually before 2 years of age. Home videos, taken before the problems are recognized, offer an objective source for detecting early signs.

Methods  Thirty‐six health visitors and midwives were invited to view brief examples from home videos of a cohort of 14 infants with RD and 11 control infants with normal development in the first year of life, and to indicate, by pressing a button, points in the recordings which aroused their suspicion of developmental deviation. They were then invited to comment on their selection. The participants were blind as to whether any individual example showed an infant with normal development or one with some form of developmental disturbance.

Results  From the first month of life and throughout the first year, infants with RD received more button presses than controls (46%, 361 out of 778 viewings) in comparison with the control group (12%, 67 of 558). The consistent nature of the health professionals’ comments made possible their categorization under four headings: appearance, posture, movement and contact. In the first month of life, the hand postures of infants with RD received particular comment from midwives (23 out of 37 comments overall on posture).

Conclusions  The present study strongly suggests the presence of early signs of developmental deviation in infants with RD, although, in most cases, formal developmental screening procedures have failed to detect these before the ages of 12 or 18 months.
Long‐term prognosis of children with Down's syndrome and leukaemia: a 34‐year nation‐wide experience
Authors: Rajantie J. , Siimes M. A.
Published: October 2003

Background  Although the characteristics of leukaemia in patients with Down's syndrome (DS) have been well documented, little is known about the long‐term results of treatment.

Method  Retrospectively from 1968 to 1981 and prospectively from 1982 to 2002, the present authors collected data on every child with DS in Finland who had been diagnosed with leukaemia between 1968 and 1994.

Results  Forty‐one children with DS had acute leukaemia: 28 had acute lymphoblastic leukaemia (ALL); and 13 had acute non‐lymphoblastic leukaemia (ANLL). The median age of the subjects at diagnosis was 3.8 years (range = 0–15.9 years). Patients with ANLL were significantly younger (P = 0.001) and all patients under 2 years of age had ANLL. Out of the 28 patients with ALL, 23 (82%) entered primary remission, and of these 23 individuals, 10 remained alive and in continuous remission (CR) after a median of 11.6 years (range = 8.9–20.0 years). Out of the 13 patients with ANLL, five (38%) entered remission and four remained in CR after a median of 16.0 years (range = 9.1–19.2 years). Treatment

‐related toxicities were common: eight patients with ALL and two with ANLL died of septicaemia. Actuarial, event‐free survival rates at 5 years were 53% and 43% for adequately treated subjects with ALL and ANLL, respectively.

Conclusions  Standard leukaemia chemotherapy is effective in patients with DS. However, because toxicities are unacceptably frequent, specific anti‐leukaemia regimens are needed for subjects with DS design.
An audit of investigations into allegations of abuse involving adults with intellectual disability
Authors: Joyce T. A.
Published: October 2003

Background  The present paper describes the results of an audit of referrals to a psychology service requesting specialist assistance in the investigation of allegations of abuse.

Methods  The referrals were over a 2‐year period and case notes and records were reviewed to analyse the nature of the allegation, the characteristics of the victims or perpetrators, and the process of the investigation and its outcome.

Results  Twenty‐six people were referred for investigation into allegations of sexual or physical abuse. The referrals were for assistance with an investigative interview (n = 12), capacity to give consent to a sexual relationship (n = 8) and competence to give evidence in court (n = 6). The referrals were all in relation to adults, covering a range of ages and degrees of intellectual disability.

Conclusions  The process of the investigations suggested that a number of barriers still exist which can make decision‐making in relation to the alleged abuse extremely difficult. Resolution of the allegations through the criminal justice system was also problematic.
Risk factors for self‐injurious behaviours among 222 young children with autistic disorders
Authors: Baghdadli A. , Pascal C. , Grisi S. , Aussilloux C.
Published: October 2003

The aim of this study was to identify risk factors for self‐injurious behaviours (SIBs) in children with autistic disorders. The occurrence of SIB was examined in comparison with the following variables: chronological age, sex, adaptive skills, speech level, associated medical condition, degree of autism and parental social class. The subjects were 222 children aged under 7 years and all of them fulfilled the ICD‐10 criteria for infantile autism. Retrospective data were collected on demographic characteristics and medical condition. Children were assessed in terms of speech, degree of autism and adaptive skills in communication, socialization and daily living skills domains. Results indicated that 50% of the children experienced SIB and 14.6% had severe SIBs. Lower chronological age, associated perinatal condition, a higher degree of autism and a higher daily living skills delay were risk factors of SIBs but parental class, sex and epilepsy were not.
Incidence determinants of gonorrhea, chlamydial genital infection, syphilis and chancroid in attendees at a sexually transmitted disease clinic in Athens, Greece
Authors: Kyriakis Kyriakos P. , Hadjivassiliou Maria , Paparizos Vassilios A. , Flemetakis Alexandros , Stavrianeas Nikolaos , Katsambas Andreas
Published: October 2003

Objective  To determine the specific impact on the incidence rate of some demographic and behavioral characteristics in outpatients with four bacterial sexually transmitted diseases (STDs).

Study design  A cross‐sectional hospital outpatient‐based study was conducted from 1990 to 1996 on 1064 consecutive symptomatic STD cases (Chlamydia trachomatis, n = 375; gonorrhea, n = 369; early symptomatic syphilis, n = 288, and chancroid, n = 32) using a standardized questionnaire.

Results  In a reference STD population of 5831 symptomatic outpatients, the relative incidence of gonorrhea, syphilis and chancroid was found to be increased among immigrants. Low educational/socioeconomic level was also a significant incidence predictor. Older age characterized homo/bisexuals. The chlamydial infection detection rate was not affected by nationality, injecting drug use history or sexual orientation in males.

Conclusion  Innovative preventive and control strategies are needed among immigrants, older men having sex with men and injecting drug users, apart from those targeting the general population.
Critical review of the manner in which the efficacy of therapies for rosacea are evaluated
Authors: Gupta Aditya K. , Chaudhry Maria M.
Published: October 2003

Background  Rosacea is a relatively common disorder that may affect individuals of all races, particularly those of northern European decent. Its onset generally occurs in individuals between the ages of 20 and 50 years. Rosacea may be classified into four subtypes and one variant. Although individuals with rosacea may not pass through all of the stages, the primary features of the disorder include frequent flushing and blushing, nontransient erythema, the presence of papules and pustules, and telangiectasia. Many agents have been used to treat rosacea stigmata, especially because none of these is uniformly effective.

Aim  To identify the parameters that are used to evaluate the response to therapy when different agents are used to treat rosacea. For a given parameter, to determine whether the different trials are consistent in the manner in which this variable is measured.

Methods  The reports on the efficacy and safety of the different drug therapies used to treat rosacea were identified. We searched MEDLINE (1966 to June 2002) for studies where rosacea was treated. The parameters used to evaluate the efficacy of therapy were determined. For each parameter, the ways in which it has been measured were identified.

Results  Efficacy of treatment is generally judged by evaluating the effect of the intervention on papules and pustules, erythema, and telangiectasia. Manual lesional counts of papules and pustules are usually performed. There is, however, substantial variation in the methodology chosen for comparison of erythema and telangiectasias. Color scales are popular for erythema and telangiectasia, while grading scales are most commonly used for physician and patient evaluations.

Conclusions  For each of the parameters that are commonly used to measure the efficacy of treatments for rosacea, the different approaches by which it has been measured in the various trials have been highlighted; these dissimilarities can make it problematic to compare between clinical trials. A greater degree of uniformity in the manner in which the various parameters are evaluated would enable a more objective comparison between the studies.
IgG antibody reactivity to Borrelia burgdorferi sensu stricto antigens in patients with morphea in Colombia
Authors: Palacios Ricardo , Torres Antonio , Trujillo Rodolfo
Published: October 2003

Background  Morphea and lichen sclerosus et atrophicus (LSA) are sclerotic skin lesions of unknown etiology involving connective tissue. The hypothesis of a borrelial origin of morphea and LSA is currently controversial.

Methods  Immunoglobulin G (IgG) immunoblot serologies against Borrelia burgdorferi in patients with morphea and LSA were analyzed and compared with those from healthy donors and patients with syphilis to determine the association with a probable borrelial agent in Colombia.

Results  No significant differences in the number of reactive antigenic bands were found between morphea/LSA patients and syphilis patients or healthy donors. The presence of at least one of the following bands, p28, p39, or p45, was the criterion most able to distinguish morphea/LSA, yielding a specificity of 95% and a sensitivity of 28.6%. Using this criterion as evidence of putative exposure to a causative borrelial agent, sclerotic skin lesions had an odds ratio of 7.60 (95% confidence interval, 1.47–39.23).

Conclusions  These results could be explained by cross‐reactivity; however, the partial shared reactivity of sera from patients with syphilis and morphea/LSA does not rule out the possibility that a new spirochetal agent, unrelated to B. burgdorferi or Treponemas, may be the causative agent of morphea/LSA in Colombia.
Cutaneous Wegener's granulomatosis (malignant pyoderma) in a patient with Crohn's disease
Authors: Jacob Sharon E. , Martin Lucy K. , Kerdel Francisco A.
Published: October 2003

We report a case of an unusual presentation of Wegener's granulomatosis (WG) in a patient with Crohn's disease (CD). She presented to our Wound Care Center with 7th cranial nerve palsy and facial pyoderma‐like ulcerations. Although WG has a predilection for the lung, kidney, and eyes, cutaneous involvement can be seen in 50% of the cases, and it can be the presenting sign in 9–14%. Because of the lethality of WG if not properly treated, the diagnosis is imperative.
Wegener's granulomatosis presenting as pyoderma gangrenosum
Authors: Szõcs Hajnal Irén , Torma Katalin , Petrovicz Edina , Hársing Judit , Fekete György , Kárpáti Sarolta , Horváth Attila
Published: October 2003

A 59‐year‐old male patient developed a necrotizing ulceration on the right shin. Both clinical and histopathologic examinations suggested pyoderma gangrenosum. After temporary improvement of skin symptoms under peroral glucocorticoid treatment, a hemorrhagic‐purulent discharge started from the nose, he began to have fever, malaise, cough, and a chest X‐ray revealed inflammation in the lung. Cerebral CT and MRI disclosed midline bone loss within the nasal septum and granulomatosus tissue masses protruding into the right orbit. The c‐ANCA test was positive, serum IgA was elevated, and he had microhaematuria and proteinuria. In this severe case of Wegener's granulomatosis prolonged methylprednisone and cyclophosphamide treatment was initiated. Both the skin symptoms and the granulomatosus infiltrations resolved.