Evidence of Recent Population Recovery in Common Eiders Breeding in Western Greenland

ABSTRACT Severe population declines were reported for common eiders (Somateria mollissima) in western Greenland over the period 1960–2000. A monitoring program, concurrent with more restrictive hunting regulations on common eiders, revealed breeding numbers increasing by 212%, from 2,558 active nests in 2000 to 7,982 nests in 2007. Though it was not possible to directly link harvest reduction and population growth in West Greenland, a similar increase in breeding numbers in Canada was correlated with the harvest reduction in Greenland and linked to increasing adult survival and recruitment of first-time breeders, and a similar explanation is suggested for West Greenland. The study emphasizes that appropriate restrictions in hunting can be efficient in wildlife management and that common eiders can sustain dramatic rates of increase during population regrowth. It also shows that cost-efficient monitoring programs can be established through cooperation with local residents.     

Effects of macromolecular crowding on the structural stability of human α-lactalbumin

The folding of protein, an important process for protein to fulfill normal functions, takes place in crowded physiological environments. α-Lactalbumin, as a model system for protein-folding studies, has been used extensively because it can form stable molten globule states under a range of conditions. Here we report that the crowding agents Ficoll 70, dextran 70, and polyethylene glycol (PEG) 2000 have different effects on the structural stability of human α-lactalbumin (HLA) represented by the transition to a molten globule state: dextran 70 dramatically enhances the thermal stability of Ca(2+)-depleted HLA (apo-HLA) and Ficoll 70 enhances the thermal stability of apo-HLA to some extent, while PEG 2000 significantly decreases the thermal stability of apo-HLA. Ficoll 70 and dextran 70 have no obvious effects on trypsin degradation of apo-HLA but PEG 2000 accelerates apo-HLA degradation by trypsin and destabilizes the native conformation of apo-HLA. Furthermore, no interaction is observed between apo-HLA and Ficoll 70 or dextran 70, but a weak, non-specific interaction between the apo form of the protein and PEG 2000 is detected, and such a weak, non-specific interaction could overcome the excluded-volume effect of PEG 2000. Our data are consistent with the results of protein stability studies in cells and suggest that stabilizing excluded-volume effects of crowding agents can be ameliorated by non-specific interactions between proteins and crowders.     

Approaches towards understanding methionine biosynthesis in higher plants

Summary. Plants are able to synthesise all amino acids essential for human and animal nutrition. Because the concentrations of some of these dietary constituents, especially methionine, lysine, and threonine, are often low in edible plant sources, research is being performed to understand the physiological, biochemical, and molecular mechanisms that contribute to their transport, synthesis and accumulation in plants. This knowledge can be used to develop strategies allowing a manipulation of crop plants, eventually improving their nutritional quality. This article is intended to serve two purposes. The first is to provide a brief review on the physiology of methionine synthesis in higher plants. The second is to highlight some recent findings linked to the metabolism of methionine in plants due to its regulatory influence on the aspartate pathway and its implication in plant growth. This information can be used to develop strategies to improve methionine content of plants and to provide crops with a higher nutritional value. Received January 28, 2000 Accepted March 3, 2000     

Poor effectiveness of the Natura 2000 network protecting Mediterranean lichen species

Evaluation of the effectiveness of protected areas networks for conserving diversity is a demanding topic in biological conservation. In the last few years, there has been an increasing number of studies on species distribution modelling which can be easily used to test the efficiency of reserve networks. Unfortunately, this effort has been focused on the so called charismatic species. Our main goal is to test the effectiveness of the Natura 2000 network by using non-charismatic species. We determined potential distribution patterns for 18 lichen species in Spain and evaluated the effectiveness of the Natura 2000 network in protecting them. Models were implemented with ENFA (Ecological-Niche Factor Analysis) because this modelling approach only requires presence data since the reliability of absence data is really poor. Habitat suitability maps were obtained and high suitability areas were characterised using ten environmental predictors. Maps of areas of high suitability were overlaid with the Natura 2000 network cover, considering the different biogeographical regions present in mainland Spain. The effectiveness of the Natura 2000 was quite low in most species. The analysis per region showed that Mediterranean lichen species growing in forests are better protected than species found in coastal, drier and warmer areas. Our results indicate that the Natura 2000 network, a protection system based on vascular plants, does not guarantee the protection of Mediterranean lichen species. Thus, this type of gap analysis and especially the inclusion of “non-charismatic” organisms such as lichens should be considered in studies to define protected areas.     

Modelling Heterogeneous Dispersion in Marginal Models for Longitudinal Proportional Data

Continuous proportional data is common in biomedical research, e.g., the pre‐post therapy percent change in certain physiological and molecular variables such as glomerular filtration rate, certain gene expression level, or telomere length. As shown in (Song and Tan, 2000) such data requires methods beyond the common generalised linear models. However, the original marginal simplex model of (Song and Tan, 2000) for such longitudinal continuous proportional data assumes a constant dispersion parameter. This assumption of dispersion homogeneity is imposed mainly for mathematical convenience and may be violated in some situations. For example, the dispersion may vary in terms of drug treatment cohorts or follow‐up times. This paper extends their original model so that the heterogeneity of the dispersion parameter can be assessed and accounted for in order to conduct a proper statistical inference for the model parameters. A simulation study is given to demonstrate that statistical inference can be seriously affected by mistakenly assuming a varying dispersion parameter to be constant in the application of the available GEEs method. In addition, residual analysis is developed for checking various assumptions made in the modelling process, e.g., assumptions on error distribution. The methods are illustrated with the same eye surgery data in (Song and Tan, 2000) for ease of comparison. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effects of phosphatidylserine on membrane incorporation and surface protection properties of exchangeable poly(ethylene glycol)-conjugated lipids

Liposomes containing the acidic phospholipid phosphatidylserine (PS) have been shown to avidly interact with proteins involved in blood coagulation and complement activation. Membranes with PS were therefore used to assess the shielding properties of poly(ethylene glycol 2000)-derivatized phosphatidylethanolamine (PE-PEG(2000)) with various acyl chain lengths on membranes containing reactive lipids. The desorption of PE-PEG(2000) from PS containing liposomes was studied using an in vitro assay which involved the transfer of PE-PEG(2000) into multilamellar vesicles, and the reactivity of PS containing liposomes was monitored by quantifying interactions with blood coagulation proteins. The percent inhibition of clotting activity of PS liposomes was dependent on the PE-PEG(2000) content. 1,2-Distearoyl-sn-glycero-3-phosphoethanolamine (DSPE)-PEG(2000) which transferred out slowly from PS liposomes was able to abolish >80% of clotting activity of PS liposomes at 15 mol%. This level of DSPE-PEG(2000) was also able to extend the mean residence time of PS liposomes from 0.2 h to 14 h. However, PE-PEG(2000) with shorter acyl chains such as 1,2-dimyristyl-sn-glycero-3-phosphoethanolamine-PEG(2000) were rapidly transferred out from PS liposomes, which resulted in a 73% decrease in clotting activity inhibition and 45% of administered intravenously liposomes were removed from the blood within 15 min after injection. Thus, PS facilitates the desorption of PE-PEG(2000) from PS containing liposomes, thereby providing additional control of PEG release rates from membrane surfaces. These results suggest that membrane reactivity can be selectively regulated by surface grafted PEGs coupled to phosphatidylethanolamine of an appropriate acyl chain length.     

A Relevance Index for the habitat areas of Natura 2000 Network based on their Rarity and Representativeness

The 231 habitat types included in the European Environmental Agency (EEA) database of the Natura 2000 Network are distributed throughout more than 22 thousand Sites of Community Importance (SCI) covering around 128 million hectares in Europe. However, individual habitat areas have different conservation relevance according to the Rarity of the habitat type and their Representativeness in relation to the whole type.We propose a Relevance Index and evaluate it for each area of each habitat type, taking into account the Rarity of the habitat type, assessed by the extent of its occurrence in the Natura 2000 Network, and the Representativeness of the area, as the contribution of that area to the total extent of that habitat type in the Network.Results allow for an objective analysis of the Natura 2000 Network indicating, for example, that rarity of a habitat type in Natura 2000 Network does not necessarily correlate with its priority status, suggesting the need for reevaluation of the situation.The Relevance Index proposed for a given habitat area is the product of the Rarity Index of its habitat type and the Representativeness of the area. We demonstrate the application of the Index for the areas of three different Natura 2000 Sites. The Relevance Index of one Site (SRI) will be the sum of the Relevance Indices of its corresponding habitat areas (HRI). The same approach is applicable to regions, countries or for any habitat cluster allowing for the quantification of their contribution to the whole Natura 2000 Network.It is suggested that the Relevance index can also be applied in monitoring the components of the Natura 2000 Network, and is useful to support management decisions for conservation in Europe.     

The Closest BLAST Hit Is Often Not the Nearest Neighbor

It is well known that basing phylogenetic reconstructions on uncorrected genetic distances can lead to errors in their reconstruction. Nevertheless, it is often common practice to report simply the most similar BLAST (Altschul et al. 1997) hit in genomic reports that discuss many genes (Ruepp et al. 2000; Freiberg et al. 1997). This is because BLAST hits can provide a rapid, efficient, and concise analysis of many genes at once. These hits are often interpreted to imply that the gene is most closely related to the gene or protein in the databases that returned the closest BLAST hit. Though these two may coincide, for many genes, particularly genes with few homologs, they may not be the same. There are a number of circumstances that can account for such limitations in accuracy (Eisen 2000). We stress here that genes appearing to be the most similar based on BLAST hits are often not each others closest relative phylogenetically. The extent to which this occurs depends on the availability of close relatives present in the databases. As an example we have chosen the analysis of the genomes of a crenarcheaota species Aeropyrum pernix, an organism with few close relatives fully sequenced, and Escherichia coli, an organism whose closest relative, Salmonella typhimurium, is completely sequenced.     

Application of oligo-(14-amino-3,6,9,12-tetraoxatetradecanoic acid) lipid conjugates as steric barrier molecules in liposomal formulations.

Lipid conjugates of oligo-(14-amino-3,6,9,12-tetraoxatetradecanoic acid) (ATTAn) were synthesized as monodisperse analogues of poly(ethylene glycol) (PEG) derivatives used in liposomal drug delivery systems. The new lipids were shown to be at least equivalent to MePEGA-2000-DSPE in assays designed to evaluate the effectiveness of polymers as steric barrier molecules in liposomes. Liposomes containing 1-5% of ATTA8-DSPE (octamer) showed comparable long circulation behavior relative to PEG-2000-DSPE analogues. Surprisingly, the shorter ATTA4-DSPE (tetramer) appeared to be quite effective in reducing clearance. Liver enzyme levels and systemic single dose tolerability of ATTA8-DSPE liposomes were comparable to controls, suggesting that the new materials are nontoxic. Prolonged exposure of ATTA8-DSPE liposomes to splenocytes in vitro showed no evidence of mitogenicity relative to controls or MePEGA-2000-DSPE liposomes. ATTA8-DSPE was as effective as MePEGC-2000-DSPE in preventing complement activation by cationic liposome systems. Repeat dosage in vivo regimes in ICR mice using DSPC/cholesterol liposomes, with and without 5% ATTA8-DSPE and MePEGC-2000-DSPE, showed no evidence of enhanced clearance on successive doses. Splenocytes recovered after repeat doses showed no significant evidence of mitogenicity on restimulation with liposomes. Cellular differentiation and activation marker levels in splenocytes recovered after the fourth in vivo administration were at normal levels. These results suggest that ATTAn oligomers do not induce an immune response in isolation. It was demonstrated that ATTA8-DSPE could be used to replace PEG-lipids in the formulation of doxorubicin, plasmid DNA and oligonucleotides using a variety of formulation techniques. The study demonstrates that ATTAn oligomers can be safely and effectively used in place of poly(ethylene glycol) as well-defined biomaterials in liposomal applications where reproducible behavior is critical.     

Avian colour vision and avian video playback experiments

Video playback potentially allows the presentation, manipulation, and replication of realistic moving visual stimuli, in a way that is impossible with real animals or static dummies, and difficult even with mechanical models. However, there are special problems attached to the use of this technology; this article concentrates on the problem of accurate colour rendition. Video and television simulate the colour of objects rather than reproduce the spectrum of light that they naturally emit, transmit, or reflect. This simulation is achieved by using relatively narrow waveband light to stimulate the cone cells in the retina in a similar pattern to that produced by the natural object. However, species differ in the spectral tuning of their photoreceptors, so a faithful colour rendition for a human is unlikely to be achieved for another species. This problem is discussed with special reference to birds, a taxon renown for its colourfulness and frequent use in behavioural experiments but which has a very different colour vision from that of humans. We stress that the major pitfalls that can arise when using video playback with avian subjects can also occur in ’normal’ behavioural experiments. However, the problems of faithful colour rendition are particularly severe with video, and the major benefits that the technology brings will only be realised under a limited range of circumstances, with careful validation experiments. Received: 24 January 2000 / Received in revised form: 28 March 2000 / Accepted: 1 April 2000     

A bioinformatics approach for determining sample identity from different lanes of high-throughput sequencing data

The ability to generate whole genome data is rapidly becoming commoditized. For example, a mammalian sized genome (～3Gb) can now be sequenced using approximately ten lanes on an Illumina HiSeq 2000. Since lanes from different runs are often combined, verifying that each lane in a genome's build is from the same sample is an important quality control. We sought to address this issue in a post hoc bioinformatic manner, instead of using upstream sample or "barcode" modifications. We rely on the inherent small differences between any two individuals to show that genotype concordance rates can be effectively used to test if any two lanes of HiSeq 2000 data are from the same sample. As proof of principle, we use recent data from three different human samples generated on this platform. We show that the distributions of concordance rates are non-overlapping when comparing lanes from the same sample versus lanes from different samples. Our method proves to be robust even when different numbers of reads are analyzed. Finally, we provide a straightforward method for determining the gender of any given sample. Our results suggest that examining the concordance of detected genotypes from lanes purported to be from the same sample is a relatively simple approach for confirming that combined lanes of data are of the same identity and quality.     

Mechanism for action of electromagnetic fields on cells

A biophysical model for the action of oscillating electric fields on cells, presented by us before [Biochem. Biophys. Res. Commun. 272(3) (2000) 634-640], is extended now to include oscillating magnetic fields as well, extended to include the most active biological conditions, and also to explain why pulsed electromagnetic fields can be more active biologically than continuous ones. According to the present theory, the low frequency fields are the most bioactive ones. The basic mechanism is the forced-vibration of all the free ions on the surface of a cell's plasma membrane, caused by an external oscillating field. We have shown that this coherent vibration of electric charge is able to irregularly gate electrosensitive channels on the plasma membrane and thus cause disruption of the cell's electrochemical balance and function [Biochem. Biophys. Res. Commun. 272(3) (2000) 634-640]. It seems that this simple idea can be easily extended now and looks very likely to be able to give a realistic basis for the explanation of a wide range of electromagnetic field bioeffects.     

Beyond 2000: science/biology education for the future

A number of countries are currently tackling the issue of curriculum reform in school science. In England and Wales, a 5-year moratorium on curriculum reform across the 5-16 age range will end in the year 2000. This article reviews the conclusions of a 2-year project, funded by the Nuffield Foundation, which explored ways in which a new science curriculum might be constructed and what it might look like. Particular attention is paid to the aims of science education, to the relationship between the content of a syllabus and its assessment, and to the suggestion that the science curriculum would be better presented as a relatively small number of explanatory stories rather than as a mass of detail. The proposals outlined here would allow for small but significant changes in the year 2000, and for more substantive changes thereafter, to be introduced only after adequate trialling. Our hope is that school science education in England and Wales can build on some of its current strengths and address certain weaknesses, leading to a more relevant and fulfilling education for future generations.     

城市可持续发展能力的能值评价新指标

能值理论、方法克服了传统能量与经济分析方法的诸多缺憾,为城市可持续发展的研究提供了全新的视角。但作为一种新兴的理论,其评价指标,尤其是针对城市可持续发展能力的综合评价指标尚不完善。从生态经济效益及环境影响的全面表达角度,剖析了国际现行可持续发展能值指标(ESI)的不足之处,并在此基础上拓展构建了新的可持续发展能值指标(EISD)。以珠江三角洲中山市1996～2000年的发展动态为例进行了案例研究。结果表明,新拓展的可持续发展能值指标．在系统效益评价中考虑了系统能值产出的实际经济效果,在环境影响评价中同时考虑了系统的消耗影响和排放影响,可以更全面明晰的评价城市系统的可持续发展能力、状态及其成因,为系统的优化指明方向。     

Collecting and tabulating race/ethnicity data with diverse and mixed heritage populations: A case-study with US high school students

The increasing diversity of the US coupled with the continuing need for information gathered about race/ethnicity require us to re-examine our practices of collecting and tabulating such data, particularly from individuals of mixed heritage. In the context of Census 2000, which allowed people for the first time to identify with multiple race groups, this article focuses on the context of education and looks at high school students’ self-­identification practices on forms. Survey data gathered from 638 freshmen during 1999–2000 at a diverse, public high school in California indicate: there can be high levels of inconsistency in students’ individual identifications depending on question format and response options provided; and, overall demographic counts can greatly vary depending on how multiple-response data are tabulated. Students’ responses raise questions about whether it is possible to attain a high level of measurement reliability when working with a diverse population that includes individuals of mixed ­heritage.     

Unbiased and Locally Efficient Estimation of Genetic Effect on Quantitative Trait in the Presence of Population Admixture

Summary Population admixture can be a confounding factor in genetic association studies. Family‐based methods ( Rabinowitz and Larid, 2000 , Human Heredity 50, 211–223) have been proposed in both testing and estimation settings to adjust for this confounding, especially in case‐only association studies. The family‐based methods rely on conditioning on the observed parental genotypes or on the minimal sufficient statistic for the genetic model under the null hypothesis. In some cases, these methods do not capture all the available information due to the conditioning strategy being too stringent. General efficient methods to adjust for population admixture that use all the available information have been proposed ( Rabinowitz, 2002 , Journal of the American Statistical Association 92, 742–758). However these approaches may not be easy to implement in some situations. A previously developed easy‐to‐compute approach adjusts for admixture by adding supplemental covariates to linear models ( Yang et al., 2000 , Human Heredity 50, 227–233). Here is shown that this augmenting linear model with appropriate covariates strategy can be combined with the general efficient methods in Rabinowitz (2002) to provide computationally tractable and locally efficient adjustment. After deriving the optimal covariates, the adjusted analysis can be carried out using standard statistical software packages such as SAS or R . The proposed methods enjoy a local efficiency in a neighborhood of the true model. The simulation studies show that nontrivial efficiency gains can be obtained by using information not accessible to the methods that rely on conditioning on the minimal sufficient statistics. The approaches are illustrated through an analysis of the influence of apolipoprotein E (APOE) genotype on plasma low‐density lipoprotein (LDL) concentration in children.     

Spatial Imprint of Food Consumption: A Historical Analysis for Sweden, 1870–2000

Depending on quantity and composition of food as well as on production conditions and techniques, the space needed to sustain an individual’s nourishment varies. The amount of space needed also depends on the use of resources such as energy, water, and fertilizers, as well as potential land degradation and water pollution. Our study focuses on the changing spatial imprint of an average inhabitant of an expanding Swedish city, Linköping, from 1870 to 2000 taking into account both shifts in consumption as well as agricultural productivity and practices. Despite the distinctly larger amount of animal food products, such as meat and fish, consumed in 2000, we calculate the area needed to sustain an individual’s annual food consumption could be less than one fourth of that needed in 1870. However, if the import of various globally produced foods is included in our calculations, the land needed to sustain the consumption of an inhabitant of Linköping in 2000 doubles. We also argue that an examination of this regional imprint can be used to explore and evaluate possibilities for regional development.     

Potent antiemetic effects of the new serotonin antagonists.

Diabetic retinopathy progresses through three distinct stages. A rational approach to management is based on an understanding of the pathophysiology of each stage. Based on the results of national multicentered clinical trials of laser photocoagulation and other treatments, advances in our understanding of the pathogenesis and treatment can now make a dramatic impact on blindness in the diabetic population: Panretinal laser photocoagulation treatment can reduce the risk of vision loss from high-risk proliferative diabetic retinopathy by at least 50%. Laser photocoagulation treatment of clinically significant diabetic macular edema can reduce the risk of vision loss by more than 50%. Vitrectomy can restore useful vision to some patients with severe diabetic retinopathy and vitreous hemorrhage with or without an accompanying traction retinal detachment. Diabetes 2000 is a new project sponsored by the American Academy of Ophthalmology, the goal of which is to eliminate preventable blindness from diabetes by the year 2000. As its name implies, Diabetes 2000 will be a long-term project aimed at a specific disease--diabetic retinopathy and its complications. It will provide the latest research findings to ophthalmologists and primary care physicians as the first priority, followed by the education of patients and the general public. Recent advances and treatment guidelines for the medical and surgical treatment of diabetic eye disease will be emphasized through the continuing education of ophthalmologists, other physicians, and allied health professionals. In later phases, educational programs for diabetic persons and the public will be developed.(ABSTRACT TRUNCATED AT 250 WORDS)