bluuebunny/crossref_metadata_2025 huggingface dataset:
Statistical analysis of labelling patterns of mammary carcinoma cell nuclei on histological sections
Authors: MATTFELDT T. , ECKEL S. , FLEISCHER F. , SCHMIDT V.
Published: June 2009

It is of central interest for tumour biology to explore the mechanisms of tumour cell proliferation. In this study, methods of spatial statistics were used to study the spatial distribution of proliferating cells within tumour tissue quantitatively and objectively. Mammary cancer tissue was studied as an example. It was attempted to clarify whether cell division occurs entirely at random (random labelling), i.e. the process of division occurs at random, independently from the state of the neighbouring nuclei, or whether the spatial distribution of proliferation is more complex, e.g. in the form of actively proliferating clusters alternating with relatively silent zones. In the case of random labelling, the reduced second moment functions K(r) of the labelled and the unlabelled nuclei would be identical. The same would hold for the pair correlation functions g(r). The alternative hypothesis is that the second‐order properties of the processes of the labelled and the unlabelled nuclei are different. Twenty cases of invasive ductal mammary carcinomas were studied. The nuclei of proliferating cells were stained immunohistochemically with the monoclonal antibody MIB‐1, which detects specifically the proliferation‐associated nuclear antigen Ki 67. The planar coordinates of the tumor cell nucleus profiles from two rectangular visual fields per case were recorded. For each visual field, the following investigations were performed: estimation of the explorative summary characteristics K(r) and g(r), fitting of the parameters of a stationary Strauss hard‐core model to the observed point patterns, estimation of two distance‐dependent Simpson indices and Monte Carlo tests of all individual patterns on the null hypothesis of random labelling. Significant differences between the mean K‐functions and the mean g‐functions of the labelled and the unlabelled nuclei were found. Moreover, the mean interaction parameter γ of the stationary Strauss hard‐core model was significantly higher for the labelled nuclei than for the unlabelled nuclei. The estimates of the two distance‐dependent Simpson indices showed a tendency of points with the same label towards a positive spatial correlation. In the Monte Carlo tests, the null hypothesis of random labelling was rejected for the majority of the visual fields. These four lines of investigation led to the concordant conclusion that the labelling of mammary carcinoma nuclei by MIB‐1 is not simply random. The data suggest that the second‐order properties of the point process of the labelled nuclei are significantly different from those of the unlabelled nuclei. In particular, the process of the labelled nuclei shows a higher degree of clustering (increased strength of interaction) than the process of the unlabelled points.
In vivo comparison of force development with various materials of implant‐supported prostheses
Authors: KIM H. K. , HEO S. J. , KOAK J. Y. , KIM S. K.
Published: June 2009

Summary  The purpose of this study was to measure axial loading, generating bending moments on fibre reinforced composite (FRC) implant prostheses using strain‐gauged customized abutment in vivo. Bending moments of conventional implant prosthetic material were also measured and the data were compared with those for FRC. Three unit fixed dental prostheses were made for two dental implant fixtures, which had been functioning properly for more than one year using TesceraTM ATLTM, porcelain fused to metal and gold as occlusal material. Three patients participated in this study; two patients had two implants on one side of the mandible and one had two implants on both sides of the mandible. Five sets of fixed dental prostheses were fabricated for each material and these were cemented with Temp‐bond® on strain‐gauged customized abutments, which were screwed into the underlying implant fixtures. Axial loadings and bending moments were measured when a patient bit the experimental fixed dental prosthesis. anova and the Tukey HSD test (α = 0·05) were used for statistical analysis. There were no significant differences in normalized bending moments among the three different implant prosthetic materials. Within the limitations of this study, TesceraTM ATLTM generated bending moments similar to conventional implant prosthetic materials such as gold and porcelain.
Redistribution of slow wave activity of sleep during pharmacological treatment of depression with paroxetine but not with nefazodone
Authors: ARGYROPOULOS SPILIOS V. , HICKS JANE A. , NASH JOHN R. , BELL CAROLINE J. , RICH ANNE S. , NUTT DAVID J. , WILSON SUE
Published: June 2009

It has been suggested that increase in delta sleep ratio (DSR), a marker for the relative distribution of slow wave activity (SWA) over night time, is associated with clinical response to antidepressant treatment. We examined this index and its relationship to rapid eye movement (REM) suppression before and during long‐term treatment with nefazodone, which does not suppress REM sleep, and paroxetine which does. The effect of serotonin (5‐HT2A) receptor blockade on the evolution of SWA during treatment was also investigated. In a double‐blind, randomised, parallel group, 8‐week study in 29 depressed patients, sleep electroencephalograms were performed at home at baseline, on night 3 and 10, and at 8 weeks of treatment with either paroxetine or nefazodone. SWA was automatically analysed and a modified DSR (mDSR) was derived, being the ratio of amount of SWA in the first 90 min of sleep to that in the second plus third 90‐min periods. At baseline, the pattern of SWA over night time was similar to other reports of depressed patients. mDSR improved over the course of treatment; there was no difference between remitters and non‐remitters but there was a significant drug effect and a significant drug × time effect with paroxetine patients having a much higher mDSR after treatment, regardless of clinical status. SWA and REM during antidepressant treatment appear to be interdependent and neither of them alone is likely to predict response to treatment. Higher mDSR did not predict therapeutic response. 5‐HT2A blockade by nefazodone does not increase SWA above normal levels.
Sleep and sleep homeostasis in constant darkness in the rat
Authors: DEBOER TOM
Published: June 2009

According to the two‐process model of sleep regulation, a homeostatic Process S increases during waking and decreases during sleep. The time course of Process S can be derived on the basis of changes in vigilance states and changes in electroencephalogram slow‐wave activity (SWA, activity below 4 Hz) during non‐rapid eye movement (NREM) sleep. In most mouse strains, an optimal fit between S and SWA was achieved with one increasing (active during waking and REM sleep) and one decreasing time constant (active during NREM sleep) for Process S. However, in the rat, systematic deviations in the light and dark periods were observed, which were resolved by introducing different decreasing time constants between the light and dark periods. The present study shows that this difference between the rest (light) and active (dark) phases remains, and may even be larger, after animals are adapted to constant dark conditions for at least a week. In addition, the data show that the build‐up rate of SWA at the onset of a NREM sleep episode is slow compared with the increase rate under light–dark conditions, and that this build‐up rate changes with the circadian phase. The slow build‐up rate introduces a systematic error between the simulation of Process S and SWA in NREM sleep. The circadian modulation of the build‐up rate may, together with circadian changes in NREM sleep episode duration, be the source of the necessity of introducing a difference in the decreasing time constant between the rest and active phases.
CNS arousal and neurobehavioral performance in a short‐term sleep restriction paradigm
Authors: COTE KIMBERLY A. , MILNER CATHERINE E. , SMITH BRIAN A. , AUBIN ADAM J. , GREASON TAMARA A. , CUTHBERT BRIELLE P. , WIEBE STEPHANIE , DUFFUS SHANNON E. G.
Published: June 2009

Few studies have investigated waking electrophysiological measures of arousal during sleep restriction. This study examined electroencephalogram (EEG) activity and performance during a 96‐hour laboratory protocol where participants slept a baseline night (8 h), were randomly assigned to 3‐, 5‐, or 8‐hour sleep groups for the next two nights sleep restriction (SR1, SR2), and then slept a recovery night (8 h). There were dose‐dependent deficits on measures of mood, sleepiness, and reaction time that were apparent during this short‐term bout of sleep restriction. The ratio of alpha to theta EEG recorded at rest indicated dose‐dependent changes in CNS arousal. At 9:00 hours, both the 3‐ and 5‐hour groups showed EEG slowing (sleepiness) during restriction, with the 3‐hour group exhibiting greater deficits. Later in the day at 13:00 hours, the 5‐hour group no longer exhibited EEG slowing, but the extent of slowing was more widespread across the scalp for the 3‐hour group. High‐frequency EEG, a measure of effort, was greater on the mornings following sleep restriction. The 5‐hour group had increased beta EEG at central‐parietal sites following both nights of restriction, whereas the 3‐hour group had increased beta and gamma EEG at occipital regions following the first night only. Short‐term sleep restriction leads to deficits in performance as well as EEG slowing that correspond to the amount and duration of sleep loss. High‐frequency EEG may be a marker of effort or compensation.
Information processing during sleep: the effect of olfactory stimuli on dream content and dream emotions
Authors: SCHREDL MICHAEL , ATANASOVA DESISLAVA , HÖRMANN KARL , MAURER JOACHIM T. , HUMMEL THOMAS , STUCK BORIS A.
Published: June 2009

Research has shown that external stimuli presented during sleep can affect dream content, thus reflecting information processing of the sleeping brain. Olfactory stimuli should have a stronger effect on dream emotions because their processing is linked directly to the limbic system. Because selective olfactory stimulation does not increase arousal activity, intense olfactory stimulation is therefore a prime paradigm for studying information processing during sleep. Fifteen healthy, normosmic volunteers were studied by intranasal chemosensory stimulation during rapid eye movement sleep based on air‐dilution olfactometry. For olfactory stimulation, hydrogen sulphide (smell of rotten eggs) and phenyl ethyl alcohol (smell of roses) was used and compared with a control condition without stimulation. The olfactory stimuli affected significantly the emotional content of dreams: the positively toned stimulus yielded more positively toned dreams, whereas the negative stimulus was followed by more negatively toned dreams. Direct incorporations, i.e. the dreamer is smelling something, were not found. The findings indicate that information processing of olfactory stimuli is present in sleep and that the emotional tone of dreams can be influenced significantly depending upon the hedonic characteristic of the stimulus used. It would be interesting to conduct learning experiments (associating specific odours with declarative material) to study whether this declarative material is incorporated into subsequent dreams if the corresponding odour cue is presented during sleep. It would also be interesting to study the effect of positively toned olfactory stimuli on nightmares.
A landscape genetics approach for quantifying the relative influence of historic and contemporary habitat heterogeneity on the genetic connectivity of a rainforest bird
Authors: PAVLACKY JR DAVID C. , GOLDIZEN ANNE W. , PRENTIS PETER J. , NICHOLLS JAMES A. , LOWE ANDREW J.
Published: June 2009

Landscape genetics is an important framework for investigating the influence of spatial pattern on ecological process. Nevertheless, the standard analytic frameworks in landscape genetics have difficulty evaluating hypotheses about spatial processes in dynamic landscapes. We use a predictive hypothesis‐driven approach to quantify the relative contribution of historic and contemporary processes to genetic connectivity. By confronting genetic data with models of historic and contemporary landscapes, we identify dispersal processes operating in naturally heterogeneous and human‐altered systems. We demonstrate the approach using a case study of microsatellite polymorphism and indirect estimates of gene flow for a rainforest bird, the logrunner (Orthonyx temminckii). Of particular interest was how much information in the genetic data was attributable to processes occurring in the reconstructed historic landscape and contemporary human‐modified landscape. A linear mixed model was used to estimate appropriate sampling variance from nonindependent data and information‐theoretic model selection provided strength of evidence for alternative hypotheses. The contemporary landscape explained slightly more information in the genetic differentiation data than the historic landscape, and there was considerable evidence for a temporal shift in dispersal pattern. In contrast, migration rates estimated from genealogical information were primarily influenced by contemporary landscape change. We discovered that landscape heterogeneity facilitated gene flow before European settlement, but contemporary deforestation is rapidly becoming the most important barrier to logrunner dispersal.
Bathymetric barriers promoting genetic structure in the deepwater demersal fish tusk (Brosme brosme)
Authors: KNUTSEN HALVOR , JORDE PER ERIK , SANNÆS HANNE , RUS HOELZEL A. , BERGSTAD ODD AKSEL , STEFANNI SERGIO , JOHANSEN TORILD , STENSETH NILS CHR.
Published: June 2009

Population structuring in the North Atlantic deepwater demersal fish tusk (Brosme brosme) was studied with microsatellite DNA analyses. Screening eight samples from across the range of the species for seven loci revealed low but significant genetic heterogeneity (FST = 0.0014). Spatial genetic variability was only weakly related to geographical (Euclidean) distance between study sites or separation of study sites along the path of major ocean currents. Instead, we found a significant effect of habitat, indicated by significant differentiation between relatively closely spaced sites: Rockall, which is surrounded by very deep water (>1000 m), and the Mid‐Atlantic Ridge, which is separated from the European slope by a deep ocean basin, were differentiated from relatively homogeneous sites across the Nordic Seas. Limited adult migration across bathymetric barriers in combination with limited intersite exchange of pelagic eggs and larvae due to site‐specific circulatory retention or poor survival during drift phases across deep basins may be reducing gene flow. We regard these limitations to gene flow as the most likely mechanisms for the observed population structure in this demersal species. The results underscore the importance of habitat boundaries in marine species.
Comparison of quantitative and molecular genetic variation of native vs. invasive populations of purple loosestrife (Lythrum salicaria L., Lythraceae)
Authors: CHUN YOUNG JIN , NASON JOHN D. , MOLONEY KIRK A.
Published: June 2009

Study of adaptive evolutionary changes in populations of invasive species can be advanced through the joint application of quantitative and population genetic methods. Using purple loosestrife as a model system, we investigated the relative roles of natural selection, genetic drift and gene flow in the invasive process by contrasting phenotypical and neutral genetic differentiation among native European and invasive North American populations (QST − FST analysis). Our results indicate that invasive and native populations harbour comparable levels of amplified fragment length polymorphism variation, a pattern consistent with multiple independent introductions from a diverse European gene pool. However, it was observed that the genetic variation reduced during subsequent invasion, perhaps by founder effects and genetic drift. Comparison of genetically based quantitative trait differentiation (QST) with its expectation under neutrality (FST) revealed no evidence of disruptive selection (QST > FST) or stabilizing selection (QST < FST). One exception was found for only one trait (the number of stems) showing significant sign of stabilizing selection across all populations. This suggests that there are difficulties in distinguishing the effects of nonadaptive population processes and natural selection. Multiple introductions of purple loosestrife may have created a genetic mixture from diverse source populations and increased population genetic diversity, but its link to the adaptive differentiation of invasive North American populations needs further research.
Antigens for pre‐erythrocytic malaria vaccines: building on success
Authors: SPEAKE C. , DUFFY P. E.
Published: June 2009

Immunization with attenuated pre‐erythrocytic malaria parasites can confer sterile protection against malaria in humans and rodents, and a single pre‐erythrocytic antigen incorporated in a subunit vaccine has substantially reduced clinical Plasmodium falciparum malaria episodes in African infants during phase 2 trials. Building upon this success has been hindered by technical obstacles that limit research on pre‐erythrocytic parasites, especially the liver stage (LS) parasites, and by an incomplete understanding of the immune mechanisms that confer protection in humans. Recent improvements in growing and isolating LS parasites have allowed progress in defining the transcriptome and proteome of the LS parasite, although more work remains to be done particularly for the early LS parasite of P. falciparum. Next generation pre‐erythrocytic antigens can be assessed and prioritized based on immunization studies in animals, and on models of immunity such as attenuated parasite vaccines that confer sterile protection or naturally acquired LS‐specific immune responses that correlate with protection in endemic areas. Although mechanisms of protection in humans remain poorly understood, the availability of a human malaria challenge model for early clinical testing of candidate vaccines is a valuable tool to confirm which immunogens should move forward to larger field trials.
Do we still need a malaria vaccine?
Authors: GREENWOOD B. , TARGETT G.
Published: June 2009

An unexpectedly large reduction in the burden of malaria has recently been achieved in a number of malaria endemic countries following the scaling up of effective treatment and simple vector control programmes. These achievements question the need for a partially effective malaria vaccine targeted at disease prevention. If an anti‐disease vaccine is to replace or supplement existing control measures a high level of efficacy, sustained over a number of years, will be required. Recent successes in malaria control have re‐awakened interest in the possibility of malaria elimination in areas where this was not previously considered to be a feasible objective. Malaria vaccines with transmission‐blocking properties could play a key role in future elimination programmes.
Adjuvants for malaria vaccines
Authors: COLER R. N. , CARTER D. , FRIEDE M. , REED S. G.
Published: June 2009

There is a renewed enthusiasm about subunit vaccines for malaria coincident with the formation of new alliances and partnerships raising international public awareness, attracting increased resources and the re‐focusing of research programs on adjuvant development for infectious disease vaccines. It is generally accepted that subunit vaccines for malaria will require adjuvants to induce protective immune responses, and availability of suitable adjuvants has in the past been a barrier to the development of malaria vaccines. Several novel adjuvants are now in licensed products or in late stage clinical development, while several others are in the earlier development pipeline. Successful vaccine development requires knowing which adjuvants to use and knowing how to formulate adjuvants and antigens to achieve stable, safe, and immunogenic vaccines. For the majority of vaccine researchers this information is not readily available, nor is access to well‐characterized adjuvants. In this minireview, we outline the current state of adjuvant research and development as it pertains to effective malaria vaccines.
Size‐dependent mortality in a Neotropical savanna tree: the role of height‐related adjustments in hydraulic architecture and carbon allocation
Authors: ZHANG YONG‐JIANG , MEINZER FREDERICK C. , HAO GUANG‐YOU , SCHOLZ FABIAN G. , BUCCI SANDRA J. , TAKAHASHI FREDERICO S. C. , VILLALOBOS‐VEGA RANDOL , GIRALDO JUAN P. , CAO KUN‐FANG , HOFFMANN WILLIAM A. , GOLDSTEIN GUILLERMO
Published: June 2009

Size‐related changes in hydraulic architecture, carbon allocation and gas exchange of Sclerolobium paniculatum (Leguminosae), a dominant tree species in Neotropical savannas of central Brazil (Cerrado), were investigated to assess their potential role in the dieback of tall individuals. Trees greater than ∼6‐m‐tall exhibited more branch damage, larger numbers of dead individuals, higher wood density, greater leaf mass per area, lower leaf area to sapwood area ratio (LA/SA), lower stomatal conductance and lower net CO2 assimilation than small trees. Stem‐specific hydraulic conductivity decreased, while leaf‐specific hydraulic conductivity remained nearly constant, with increasing tree size because of lower LA/SA in larger trees. Leaves were substantially more vulnerable to embolism than stems. Large trees had lower maximum leaf hydraulic conductance (Kleaf) than small trees and all tree sizes exhibited lower Kleaf at midday than at dawn. These size‐related adjustments in hydraulic architecture and carbon allocation apparently incurred a large physiological cost: large trees received a lower return in carbon gain from their investment in stem and leaf biomass compared with small trees. Additionally, large trees may experience more severe water deficits in dry years due to lower capacity for buffering the effects of hydraulic path‐length and soil water deficits.
Oxygen isotope enrichment (Δ18O) reflects yield potential and drought resistance in maize
Authors: CABRERA‐BOSQUET LLORENÇ , SÁNCHEZ CIRO , ARAUS JOSÉ LUIS
Published: June 2009

Measurement of stable isotopes in plant dry matter is a useful phenotypic tool for speeding up breeding advance in C3 crops exposed to different water regimes. However, the situation in C4 crops is far from resolved, since their photosynthetic metabolism precludes (at least in maize) the use of carbon isotope discrimination. This paper investigates the use of oxygen isotope enrichment (Δ18O) as a new secondary trait for yield potential and drought resistance in maize (Zea mays L). A set of tropical maize hybrids developed by the International Maize and Wheat Improvement Center was grown under three contrasting water regimes in field conditions. Water regimes clearly affected plant growth and yield. In accordance with the current theory, a decrease in water input was translated into large decreases in stomatal conductance and increases in leaf temperature together with concomitant 18O enrichment of plant matter (leaves and kernels). In addition, kernel Δ18O correlated negatively with grain yield under well‐watered and intermediate water stress conditions, while it correlated positively under severe water stress conditions. Therefore, genotypes showing lower kernel Δ18O under well‐watered and intermediate water stress had higher yields in these environments, while the opposite trend was found under severe water stress conditions. This illustrates the usefulness of Δ18O for selecting the genotypes best suited to differing water conditions.
Origin of Lower Cretaceous (‘Nubian’) sandstones of North‐east Africa and Arabia from detrital zircon U‐Pb SHRIMP dating
Authors: KOLODNER KEREN , AVIGAD DOV , IRELAND TREVOR RUSSELL , GARFUNKEL ZVI
Published: June 2009

Lower Cretaceous sandstones of the type exposed in Israel, deposited over much of North Africa and Arabia as widespread sandstone sheets, typically are mineralogically and texturally mature. Previous petrographic examinations suggested that the Lower Cretaceous sandstones are at least partly a product of recycling and the present study supports this notion. The results of U‐Pb Sensitive High Resolution Ion Micro‐Probe (SHRIMP) dating of detrital zircons from the Lower Cretaceous section exposed in Israel indicate that they are dominated by detrital zircons of Neoproterozoic age, mainly concentrated in the 0·55 to 0·65 Ga interval, with various amounts of older (pre‐Neoproterozoic) zircons (of 0·95 to 1·10, 1·7 to 2·0 and 2·6 to 2·65 Ga age groups). The overall age signal is similar to detrital zircon age spectra previously obtained from the Cambrian–Ordovician sections of Israel and Jordan. Remarkably, the detrital zircon spectra remained almost unchanged for nearly 400 Myr. Thus, the most probable provenance of the Lower Cretaceous sandstone is the recycling of relatively proximal Palaeozoic sandstone. Since first unroofed from above pan‐African terranes closer to the secession of orogeny, the ensuing siliciclastics were recycled repeatedly throughout the Phanerozoic with little additional basement denudation. The Lower Cretaceous sandstone comprises quartz sand that was first eroded from above pan‐African orogens ca 400 Myr prior to deposition.
Architecture of a coarse‐grained channel–levée system: the Rosario Formation, Baja California, Mexico
Authors: KANE IAN A. , DYKSTRA MASON L. , KNELLER BENJAMIN C. , TREMBLAY SACHA , McCAFFREY WILLIAM D.
Published: June 2009

Seafloor images of coarse‐grained submarine channel–levée systems commonly reveal complex braid‐plain patterns of low‐amplitude bedforms and zones of apparent bypass; however, mechanisms of channel evolution and the resultant channel‐fill architecture are poorly understood. At Playa Esqueleto the lateral relationships between various elements of a deep‐marine slope channel system are well‐exposed. Specifically, the transition from gravel‐dominated axial thalwegs to laterally persistent marginal sandstones and isolated gravel‐filled scours is revealed. Marginal sandstones pass into a monotonous thin‐bedded succession which built to form relatively low‐relief levées bounding the channel belt; in turn, the levées onlap the canyon walls. Three orders of confinement were important during the evolution of the channel system: (i) first‐order confinement was provided by the erosional canyon which confined the entire system; (ii) confined levées built of turbidite sandstones and mudstones formed the second‐order confinement, and it is demonstrated that these built from overspill at thalweg margins; and (iii) third‐order confinement describes the erosional confinement of coarse‐grained thalwegs and scours. Finer‐grained sediment was transported in suspension and largely was unaffected by topography at the scale of individual thalwegs. Facies and clast analyses of conglomerate overlying channel‐marginal scours reveal that they were deposited by composite gravity flows, which were non‐cohesive, grain‐dominant debris flows with more fluidal cores. These flows were capable of basal erosion but were strongly depositional; frictional freezing at flow margins built gravel levées, while the core maintained a more fluidal transport regime. The resultant architecture consists of matrix‐rich, poorly sorted levées bounding better‐sorted, traction‐dominated cores. The planform geometry is interpreted to have consisted of a low‐sinuosity gravel braid‐plain built by accretion around mid‐channel and bank‐attached bars. This part of the system may be analogous to fluvial systems; however, the finer‐grained sediment load formed thick suspension clouds, probably several orders of magnitude thicker than the relief of braid‐plain topography and therefore controlled by the levées and canyon wall confinement.
Delineation of the geometry of nodes in the Alps–Dinarides hinge zone and recognition of seismogenic nodes (M ≥ 6)
Authors: Gorshkov Alexander I. , Panza Giuliano F. , Soloviev Alexander A. , Aoudia Abdelkrim , Peresan Antonella
Published: June 2009

We introduce a new method based on the analysis of the topographical alignments and used to delineate the structural boundaries of the nodes, which permits the definition of relatively narrow earthquake‐prone areas by the pattern recognition approach. The structurally bounded nodes capable of earthquakes with M ≥ 6.0, identified with pattern recognition, in fact, cover a significantly smaller area of the study region as compared with that defined by Gorshkov et al. (2004) who used conventional circles. The proposed method thus improves the precision in the location of potential large earthquakes.
Slope‐control on the aspect ratio of river basins
Authors: Castelltort Sébastien , Simpson Guy , Darrioulat Alexandre
Published: June 2009

Although it is traditionally thought that drainage basins are geometrically similar, we present new results which indicate that the aspect ratio of weakly dissected river basins at large scales (10–103 km2) depends on the surface slope: steeper surfaces develop narrower and lengthier basins whereas more gently dipping surfaces develop more equant and wider basins. This relationship is interpreted to be related to the nature of water flow over rough surfaces, with steeper slopes causing less flow convergence and lengthier and narrower basins. We derive an empirical relationship that can be used to infer the slope of a surface on which a river basin acquired its geometry based solely on a measure of its basin form. This relation provides a unique means of inferring the relative chronology of river basin development with respect to surface tilting and therefore provides a direct link between river basin morphology and tectonics.
Long‐term fluctuations in volcanic activity: implications for future environmental impact
Authors: Rymer Hazel , Locke Corinne A. , Borgia Andrea , Martinez Maria , Brenes Jorge , Van der Laat Rodolfo , Williams‐Jones Glyn
Published: June 2009

Acidic crater lakes at persistently active volcanoes act as both an index and a moderator of volcanic processes. A catastrophic drop in lake level can therefore lead to serious local environmental damage. In the early 1990s, the crater lake at Poás volcano, Costa Rica diminished, and acid aerosols erupted with devastating consequences for local health, environment and economy. The first indications of this event can be  retrospectively identified to have started from 1985, on the basis of our unique 20‐year data time series, which provides evidence for the shallow intrusion of magma. New data presented in this article show similar trends and we conclude that Poás has now entered another active period with renewed intrusion. Severe environmental damage in this region is expected within the next few years if the current trend continues.
Efficacy of the solar water disinfection method in turbid waters experimentally contaminated with Cryptosporidium parvum oocysts under real field conditions
Authors: Gómez‐Couso H. , Fontán‐Saínz M. , Sichel C. , Fernández‐Ibáñez P. , Ares‐Mazás E.
Published: June 2009

Objective  To investigate the efficacy of the solar water disinfection (SODIS) method for inactivating Cryptosporidium parvum oocysts in turbid waters using 1.5 l polyethylene terephthalate (PET) bottles under natural sunlight.

Methods  All experiments were performed at the Plataforma Solar de Almería, located in the Tabernas Desert (Southern Spain) in July and October 2007. Turbid water samples [5, 100 and 300 nephelometric turbidity units (NTU)] were prepared by addition of red soil to distilled water, and then spiked with purified C. parvum oocysts. PET bottles containing the contaminated turbid waters were exposed to full sunlight for 4, 8 and 12 h. The samples were then concentrated by filtration and the oocyst viability was determined by inclusion/exclusion of the fluorogenic vital dye propidium iodide.

Results  After an exposure time of 12 h (cumulative global dose of 28.28 MJ/m2; cumulative UV dose of 1037.06 kJ/m2) the oocyst viabilities were 11.54%, 25.96%, 41.50% and 52.80% for turbidity levels of 0, 5, 100 and 300 NTU, respectively, being significantly lower than the viability of the initial isolate (P < 0.01).

Conclusions  SODIS method significantly reduced the potential viability of C. parvum oocysts on increasing the percentage of oocysts that took up the dye PI (indicator of cell wall integrity), although longer exposure periods appear to be required than those established for the bacterial pathogens usually tested in SODIS assays.
Hepatic lipase promoter C‐480T polymorphism is associated with serum lipids levels, but not subclinical atherosclerosis: The Cardiovascular Risk in Young Finns Study
Authors: Fan Y‐M , Raitakari OT , Kähönen M , Hutri‐Kähönen N , Juonala M , Marniemi J , Viikari J , Lehtimäki T
Published: June 2009

The common C‐480T polymorphism (rs1800588) of the hepatic lipase gene (LIPC) has been associated with high‐density lipoprotein (HDL) cholesterol, atherosclerosis, and coronary artery disease. In this study, we examined whether the polymorphism is associated with serum lipid and lipoprotein concentrations, as well as with subclinical atherosclerosis in Young Finns. The participants comprised 2041 men and women (aged 24–39 years) enrolled in the Cardiovascular Risk in Young Finns Study with complete data concerning the rs1800588 polymorphism and serum lipids concentration. All participants underwent an ultrasound examination for brachial artery flow‐mediated vasodilatation (FMD) and carotid artery intima‐media thickness (IMT) measurement. The marker of arterial elasticity, carotid artery compliance (CAC), was also calculated by means of ultrasound and concomitant brachial blood pressure measurements. In all subjects, serum total cholesterol (p < 0.001), HDL cholesterol (p = 0.006), apolipoprotein AI (apoAI, p < 0.001), and triglyceride (p = 0.009) concentrations increased according to rs1800588 genotype in the order CC, CT, and TT. The same order applied only to apoAI after adjustment for age, body mass index, systolic and diastolic blood pressure, smoking, alcohol consumption, physical activity, diabetes, hypertension, contraceptive hormone use in women, and concentrations of glucose, insulin and C‐reactive protein in men and women separately (p = 0.007 and p = 0.003, respectively). The polymorphism was also associated with HDL cholesterol, total cholesterol, and triglyceride levels in women (adjusted p = 0.004, p = 0.007 and 0.02, respectively), but not in men (p was not significant for all). No significant association between the rs1800588 and brachial FMD, carotid IMT, or CAC was found among the entire study population or among women or men separately, with or without adjustment for the above‐mentioned factors. The rs1800588 is associated with serum lipid and apolipoprotein concentrations, especially in women, but does not seem to be a determinant of brachial artery FMD, carotid IMT, or CAC in young healthy adults.
The ImmunoCAP® Rapid Wheeze/Rhinitis Child test is useful in the initial allergy diagnosis of children with respiratory symptoms
Authors: Eigenmann Philippe A. , Kuenzli Markus , D’Apuzzo Vincenzo , Kehrt Rainer , Joerg Walter , Reinhardt Michael , Rudengren Magnus , Borres Magnus P. , Lauener Roger P.
Published: June 2009

Recurrent upper or lower respiratory symptoms, possibly allergy‐related, are very frequent in childhood. It is therefore important that physicians involved in the primary care of these children have an accurate initial diagnostic tool available. In this study, we investigated the value of an in vitro diagnostic device testing 10 common allergens, the ImmunoCAP® Rapid Wheeze/Rhinitis Child, for the primary evaluation of allergy. Children with non‐infectious upper or lower respiratory symptoms possibly related to allergy were recruited in the primary health care setting of private practices of physician trained in immunology/allergology. The investigators carried out their usual diagnostic work‐up including IgE tests, and the ImmunoCAP® Rapid test was performed with capillary whole blood in a blinded way to the investigator. The investigators’ conclusions on major triggering allergens were compared to the ImmunoCAP® Rapid test results. In the whole patient population (n = 185), the sensitivity of the ImmunoCAP® Rapid test for unveiling allergic disease was 92% (95% CI: 86–96%) and the specificity 97% (95% CI: 86–100%). Current guidelines for allergy diagnosis suggest screening children with recurrent, moderate/severe diseases for allergies. For children with asthma falling into these categories, sensitivity was 100% (95% CI: 88–100%) and specificity 100% (95% CI: 69–100%); for children with moderate and severe rhinitis sensitivity was 93% (95% CI: 86–97%) and the specificity 100% (95% CI: 79–100%). The ImmunoCAP® Rapid test is an accurate test, in particular with regard to high specificity, for diagnosing allergy in children with recurrent respiratory diseases in primary care settings.
Outcome, timing and adverse events in therapeutic hypothermia after out‐of‐hospital cardiac arrest
Authors: NIELSEN N. , HOVDENES J. , NILSSON F. , RUBERTSSON S. , STAMMET P. , SUNDE K. , VALSSON F. , WANSCHER M. , FRIBERG H. ,   for the Hypothermia Network
Published: June 2009

Background: Therapeutic hypothermia (TH) after cardiac arrest protects from neurological sequels and death and is recommended in guidelines. The Hypothermia Registry was founded to the monitor outcome, performance and complications of TH.

Methods: Data on out‐of‐hospital cardiac arrest (OHCA) patients admitted to intensive care for TH were registered. Hospital survival and long‐term outcome (6–12 months) were documented using the Cerebral Performance Category (CPC) scale, CPC 1–2 representing a good outcome and 3–5 a bad outcome.

Results: From October 2004 to October 2008, 986 TH‐treated OHCA patients of all causes were included in the registry. Long‐term outcome was reported in 975 patients. The median time from arrest to initiation of TH was 90 min (interquartile range, 60–165 min) and time to achieving the target temperature (≤34 °C) was 260 min (178–400 min). Half of the patients underwent coronary angiography and one‐third underwent percutaneous coronary intervention (PCI). Higher age, longer time to return of spontaneous circulation, lower Glasgow Coma Scale at admission, unwitnessed arrest and initial rhythm asystole were all predictors of bad outcome, whereas time to initiation of TH and time to reach the goal temperature had no significant association. Bleeding requiring transfusion occurred in 4% of patients, with a significantly higher risk if angiography/PCI was performed (2.8% vs. 6.2%P=0.02).

Conclusions: Half of the patients survived, with >90% having a good neurological function at long‐term follow‐up. Factors related to the timing of TH had no apparent association to outcome. The incidence of adverse events was acceptable but the risk of bleeding was increased if angiography/PCI was performed.
Testosterone, growth and the evolution of sexual size dimorphism
Authors: COX R. M. , STENQUIST D. S. , CALSBEEK R.
Published: June 2009

The integration of macroevolutionary pattern with developmental mechanism presents an outstanding challenge for studies of phenotypic evolution. Here, we use a combination of experimental and comparative data to test whether evolutionary shifts in the direction of sexual size dimorphism (SSD) correspond to underlying changes in the endocrine regulation of growth. First, we combine captive breeding studies with mark‐recapture data to show that male‐biased SSD develops in the brown anole lizard (Anolis sagrei) because males grow significantly faster than females as juveniles and adults. We then use castration surgeries and testosterone implants to show that castration inhibits, and testosterone stimulates, male growth. We conclude by reviewing published testosterone manipulations in other squamate reptiles in the context of evolutionary patterns in SSD. Collectively, these studies reveal that the evolution of SSD has been accompanied by underlying changes in the effect of testosterone on male growth, potentially facilitating the rapid evolution of SSD.
Phenotypic divergence but not genetic distance predicts assortative mating among species of a cichlid fish radiation
Authors: STELKENS R. B. , SEEHAUSEN O.
Published: June 2009

The hypothesis of ecological divergence giving rise to premating isolation in the face of gene flow is controversial. However, this may be an important mechanism to explain the rapid multiplication of species during adaptive radiation following the colonization of a new environment when geographical barriers to gene flow are largely absent but underutilized niche space is abundant. Using cichlid fish, we tested the prediction of ecological speciation that the strength of premating isolation among species is predicted by phenotypic rather than genetic distance. We conducted mate choice experiments between three closely related, sympatric species of a recent radiation in Lake Mweru (Zambia/DRC) that differ in habitat use and phenotype, and a distantly related population from Lake Bangweulu that resembles one of the species in Lake Mweru. We found significant assortative mating among all closely related, sympatric species that differed phenotypically, but none between the distantly related allopatric populations of more similar phenotype. Phenotypic distance between species was a good predictor of the strength of premating isolation, suggesting that assortative mating can evolve rapidly in association with ecological divergence during adaptive radiation. Our data also reveals that distantly related allopatric populations that have not diverged phenotypically, may hybridize when coming into secondary contact, e.g. upon river capture because of diversion of drainage systems.
Adaptive brain size divergence in nine‐spined sticklebacks (Pungitius pungitius)?
Authors: GONDA A. , HERCZEG G. , MERILÄ J.
Published: June 2009

Most studies seeking to provide evolutionary explanations for brain size variability have relied on interspecific comparisons, while intraspecific studies utilizing ecologically divergent populations to this effect are rare. We investigated the brain size and structure of first‐generation laboratory‐bred nine‐spined sticklebacks (Pungitius pungitius) from four geographically and genetically isolated populations originating from markedly different habitats. We found that the relative size of bulbus olfactorius and telencephalon was significantly larger in marine than in pond populations. Significant, but habitat‐independent population differences were also found in relative brain and cerebellum sizes. The consistent, habitat‐specific differences in the relative size of bulbus olfactorius and telencephalon suggest their adaptive reduction in response to reduced (biotic and abiotic) habitat complexity in pond environments. In general, the results suggest that genetically based brain size and structure differences can evolve relatively rapidly and in repeatable fashion with respect to habitat structure.
Major disruption of gene expression in hybrids between young sympatric anadromous and resident populations of brook charr (Salvelinus fontinalis Mitchill)
Authors: MAVAREZ JESUS , AUDET CELINE , BERNATCHEZ LOUIS
Published: June 2009

Genome‐wide analyses of the transcriptome have suggested that male‐biased genes are the first targets of genomic incompatibilities (g.i.) in inter‐specific hybrids. However, those studies have almost invariably focused on Drosophila species that diverged at least 0.9 Ma, and with sterile male hybrids. Here, we use microarrays to analyse patterns of gene expression in very closely related (divergence <12 000 years), sympatric, but ecologically divergent anadromous and resident populations of brook charr (Salvelinus fontinalis) and their F1 hybrids. Our results show a dramatic breakdown of gene expression patterns in hybrids compared with their parental relatives. Several disrupted genes are related to energetic metabolism, immune response, osmoregulation and protection against oxidative stress, and none has sex‐biased functions. Besides, pure individuals show no expression differences at most of the genes disrupted in hybrids, which may suggest the operation of some form of stabilizing selection. Taken together, these results both confirm the idea that perturbations of regulatory networks represent a significant source of g.i. and support the suggestion that developmental pathways can diverge through time without any manifest change in the phenotypic outcome. While the role of other evolutionary forces (e.g. genetic drift) cannot be ruled out, this study suggests that ecological selective processes may provide the initial driving force behind disruption of gene expression in inter‐specific hybrids.
Aphid genotypes vary in their response to the presence of fungal endosymbionts in host plants
Authors: BIERI A. P. S. , HÄRRI S. A. , VORBURGER C. , MÜLLER C. B.
Published: June 2009

Genetic variation for fitness‐relevant traits may be maintained in natural populations by fitness differences that depend on environmental conditions. For herbivores, plant quality and variation in chemical plant defences can maintain genetic variation in performance. Apart from plant secondary compounds, symbiosis between plants and endosymbiotic fungi (endophytes) can produce herbivore‐toxic compounds. We show that there is significant variation among aphid genotypes in response to endophytes by comparing life‐history traits of 37 clones of the bird cherry‐oat aphid Rhopalosiphum padi feeding on endophyte‐free and endophyte‐infected tall fescue Lolium arundinaceum. Clonal variation for life‐history traits was large, and most clones performed better on endophyte‐free plants. However, the clones differed in the relative performance across the two environments, resulting in significant genotype × environment interactions for all reproductive traits. These findings suggest that natural variation in prevalence of endophyte infection can contribute to the maintenance of genetic diversity in aphid populations.
Duets in Yellow‐Naped Amazons: Variation in Syntax, Note Composition and Phonology at Different Levels of Social Organization
Authors: Dahlin Christine R. , Wright Timothy F.
Published: June 2009

Complex vocal signals composed of multiple notes are used by many species. Such signals may vary in a number of features such as the rules that govern note order and timing (syntax), the relative number and types of different notes (note composition), and the acoustic structure of notes (phonology). Previous research examining male song in songbirds typically has shown greater conservation of syntax than phonology. Here we investigated whether these patterns of variation are also found in the duets of parrots. We examined geographic variation in the pair duets of yellow‐naped amazons,Amazona auropalliata, at five sites within one vocal dialect. We also examined variation at several levels of social organization, including within pairs, among pairs and among sites, to assess where variability was greatest. Variation was highest at the within‐pair level, although variation was also present at all other levels and for all of the duet factors. We hypothesize that variation at the among‐site level allows duets to indicate site membership, while variation at the within‐pair level allows pairs to change their duet to match their current social or physical environment. Syntax and phonology are also more conserved than note composition for all levels of social organization. This pattern may result because note composition is less important in duet function than syntax or phonology, or because development of syntax and phonology is more heavily influenced by genetic templates.