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Systematic Sampling (systematic + sampling)
Selected AbstractsMicro-scale Systematic Sampling of Soil: Heterogeneity in Populations of Fusarium oxysporum, F. solani, F. roseum and F. moniliformeJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2000M. C. Rodríguez-Molina Abstract The variability of Fusarium spp. density in soil was studied in a field located in Badajoz (south-western Spain). The upper 40 cm of each side of a 1 m × 1 m × 1 m pit were sampled intensively, taking soil samples from points 10 cm apart. The species isolated were F. oxysporum, F. solani, F. roseum and F. moniliforme. For all four sides of the pit population densities of F. oxysporum, F. solani and F. roseum significantly decreased with increasing soil depth and for all the four layers significant differences were detected between sides of the pit. Horizontal variability also occurred on a smaller sampling scale: when a layer of a side was sampled, densities might be significantly different between points in the layer. However, no clear trend in horizontal variability was observed for any species. These findings demonstrate that Fusarium spp. populations were heterogeneously distributed in this reduced soil volume. Zusammenfassung Die Variabilität der Dichte von Fusarium spp. im Boden wurde in einem Feld in Badajoz (Südwestspanien) untersucht. Die oberen 40 cm jeder Seite einer 1 m × 1 m × 1 m großen Grube wurden intensiv beprobt, wobei im Abstand von jeweils 10 cm Bodenproben entnommen wurden. Aus den Proben wurden F. oxysporum, F. solani, F. roseum und F. moniliforme isoliert. An allen vier Seiten der Grube nahmen die Populationsdichten von F. oxysporum, F. solani und F. roseum mit zunehmender Bodentiefe signifikant ab. Bei allen vier Schichten wurden signifikante Unterschiede zwischen den Seiten der Grube festgestellt. Bei kleinerem Beprobungsmaßstab wurde auch horizontale Variabilität festgestellt: Wenn eine Schicht einer Seite beprobt wurde, unterschieden sich die Dichten zwischen den einzelnen Punkten der Schicht teilweise signifikant. Für keine Art war jedoch eine deutliche Tendenz bei der horizontalen Variabilität feststellbar. Die Ergebnisse zeigten, daß die Populationen von Fusarium spp. in diesem kleinen Bodenvolumen heterogen verteilt waren. [source] Responses of tropical rainforest birds to abandoned plantations, edges and logged forest in the Western Ghats, IndiaANIMAL CONSERVATION, Issue 3 2002T. R. Shankar Raman This study examined the effects of alteration of tropical rainforest vegetation structure and composition on bird community structure and the influence of life-history traits on species persistence in the Kalakad-Mundanthurai Tiger Reserve, Western Ghats. Systematic sampling for vegetation and point count surveys for birds were carried out in cardamom plantations abandoned for 5 and 15 years, plantation-rainforest edges, a selectively logged forest patch and adjoining undisturbed rainforest sites. Principal components analysis of vegetation variables revealed clear differences between undisturbed and altered sites in woody plant and cane densities, canopy cover and vertical stratification. Bird species richness was lowest in cardamom plantations abandoned for 5 years and highest in logged and undisturbed forest. Bird species richness and similarity with undisturbed forest were significantly positively related to the vegetation component representing woody plant and cane (Calamus spp.) densities. Sites that were more similar in tree species composition had more similar bird communities whereas similarity in foliage profile between sites did not influence bird community similarity. Birds that were rare, were large-bodied and belonged to the carnivore, omnivore, bark-surface feeder and terrestrial insectivore guilds were adversely affected by habitat alteration. Restoring woody plant and cane densities and rainforest floristic composition in disturbed habitats may be required for management and conservation of bird communities typical to the region. [source] Plant Community Structure in Tropical Rain Forest Fragments of the Western Ghats, India,BIOTROPICA, Issue 2 2006S. Muthuramkumar ABSTRACT Changes in tree, liana, and understory plant diversity and community composition in five tropical rain forest fragments varying in area (18,2600 ha) and disturbance levels were studied on the Valparai plateau, Western Ghats. Systematic sampling using small quadrats (totaling 4 ha for trees and lianas, 0.16 ha for understory plants) enumerated 312 species in 103 families: 1968 trees (144 species), 2250 lianas (60 species), and 6123 understory plants (108 species). Tree species density, stem density, and basal area were higher in the three larger (> 100 ha) rain forest fragments but were negatively correlated with disturbance scores rather than area per se. Liana species density, stem density, and basal area were higher in moderately disturbed and lower in heavily disturbed fragments than in the three larger fragments. Understory species density was highest in the highly disturbed 18-ha fragment, due to weedy invasive species occurring with rain forest plants. Nonmetric multidimensional scaling and Mantel tests revealed significant and similar patterns of floristic variation suggesting similar effects of disturbance on community compositional change for the three life-forms. The five fragments encompassed substantial plant diversity in the regional landscape, harbored at least 70 endemic species (3.21% of the endemic flora of the Western Ghats,Sri Lanka biodiversity hotspot), and supported many endemic and threatened animals. The study indicates the significant conservation value of rain forest fragments in the Western Ghats, signals the need to protect them from further disturbances, and provides useful benchmarks for restoration and monitoring efforts. [source] Systematic sample design for the estimation of spatial meansENVIRONMETRICS, Issue 1 2003Luis Ambrosio Flores Abstract This article develops a practical approach to undertaking systematic sampling for the estimation of the spatial mean of an attribute in a selected area. A design-based approach is used to estimate population parameters, but it is combined with elements of a model-based approach in order to identify the spatial correlation structure, to evaluate the relative efficiency of the sample mean under simple random and systematic sampling, to estimate sampling error and to assess the sample size needed in order to achieve a desired level of precision. Using two case studies (land use estimation and weed seedbank in soil) it is demonstrated how the practical basis for the design of systematic samples provided in this work should be applied and it is shown that if the spatial correlation is ignored the sampling error of the sample mean and the sample size needed in order to achieve a desired level of precision with systematic sampling are overestimated. Copyright © 2003 John Wiley & Sons, Ltd. [source] Occurrence, ecology and potential impact of the New Zealand wheat bug Nysius huttoni White (Hemiptera: Lygaeidae) in BelgiumEPPO BULLETIN, Issue 2 2010J. Bonte In 2002 the New Zealand wheat bug Nysius huttoni White was observed for the first time in the Netherlands and Belgium. The introduction of N. huttoni to these regions presumably occurred via overseas transport of apple and kiwi fruits from New Zealand. Laboratory experiments showed that both eggs and adults of N. huttoni were capable of surviving cold conditions similar to those in overseas transportation. Specimens were sampled in Belgium and the Netherlands, and a DNA sequence analysis indicated a 100% similarity with N. huttoni material collected in Christchurch, New Zealand. The distribution of the lygaeid in Belgium in 2008 was studied based on a systematic sampling at 105 locations. The bug had been able to spread over most of the Belgian territory, with the exception of the most southern and eastern provinces. Given the poor flight capacity of Belgian N. huttoni populations, other methods of dispersal may be involved. N. huttoni occurred primarily in ruderal habitats, and its weedy host plants belong to very common plant families. Several observations support N. huttoni not being a threat for agricultural crops in Belgium under the present conditions of climate and soil usage. [source] Probability models for pine twisting rust (Melampsora pinitorqua) damage in Scots pine (Pinus sylvestris) stands in FinlandFOREST PATHOLOGY, Issue 1 2005U. Mattila Summary Factors affecting the probability that pine twisting rust (Melampsora pinitorqua) damage occur in a Scots pine (Pinus sylvestris) stand were analysed using the 7th Finnish National Forest Inventory data (NFI7) from southern Finland in 1977,1983. The inventory was based on systematic sampling. The NFI7 data was measured in clusters, each of which consisted of 21 sample plots. In addition to the stand and site characteristics measured for forest management planning purposes, the data included records of damage by pine twisting rust and occurrence of aspens (Populus tremula, the other host plant of the pathogen) in the stands. Two multilevel logit models were developed for predicting the overall probability of pine twisting rust damage and the probability of severe pine twisting rust damage. Site and stand characteristics were used as explanatory variables in the models. Residual variance in the models was studied on the inventory crew, cluster and year levels. The occurrence of aspens and site fertility were the most important factors increasing the probability that pine twisting rust damage will occur in a stand. The damage probability also decreased with increasing effective temperature sum calculated for the location. The overall damage probability was equally high on peatlands and on mineral soil if there were aspens in the stand. If, however, there were no aspens in the stand, the probability of damage was higher on mineral soils than on peatlands. In addition, the overall probability was lower in naturally regenerated stands than in planted or sown stands, and it decreased with increasing mean age of pines. In both models, the residual variance was significant on the both the inventory crew and the cluster levels. Résumé Les facteurs de probabilité d'occurrence d'un dégât de rouille courbeuse (Melampsora pinitorqua) dans un peuplement de Pin sylvestre (Pinus sylvestris) ont été analysés en utilisant les données du 7 Inventaire Forestier National de Finlande (NF17) pour la Finlande du Sud et la période 1977,1983. L'inventaire est basé sur un échantillonnage systématique. Les données de NF17 sont mesurées dans des groupes constitués de 21 placettes. En plus des caractéristiques de la station et du peuplement mesurées à des fins de gestion forestière, les données comprennent des notations de dégâts par la rouille courbeuse et de présence des trembles (hôte alternant de 1'agent pathogène) dans les peuplements. Des modèles logit multiniveaux ont été développés pour prédire la probabilité globale de dégât de rouille courbeuse et la probabilité de dégât sévère. Les caractéristiques de la station et du peuplement ont été utilisées comme variables explicatives dans les modèles. La variance résiduelle des modèles a étéétudiée au niveau de 1'observateur, du groupe de placettes et de 1'année. La présence de trembles et la fertilité de la station sont les facteurs les plus importants d'augmentation de la probabilité de dégât de rouille dans un peuplement. D'autre part, la probabilité de dégât décroît avec la somme des températures effectives calculée pour le site. La probabilité globale de dégât est aussi élevée sur sols de tourbières que sur sols minéraux dans le cas où des trembles sont présents dans le peuplement. En 1'absence de trembles dans le peuplement, la probabilité de dégât est plus importante sur sols minéraux qu'en tourbières. Enfin, la probabilité de dégât est plus faible dans les peuplements régénérés naturellement que dans les peuplements semés ou plantés, et elle décroít avec 1'âge moyen des pins. Pour les deux modèles, la variance résiduelle est significative au niveau observateur et groupe de parcelles. Zusammenfassung Faktoren, die die Wahrscheinlichkeit einer Schädigung durch den Kieferndrehrost (Melampsora pinitorqua) in Beständen von Pinus sylvestris beeinflussen, wurden anhand der Daten der 7. Finnischen Nationalen Forstinventur (NF17) aus den Jahren 1977,1983 in Südfinnland untersucht. Die Datenerhebung basierte auf einer systematischen Probenahme. Die NF17 Daten wurden in Clustern erhoben, jedes Cluster bestand aus 21 Probeflächen. Neben den Bestandes- und Standortsmerkmalen, die für die forstliche Planung erhoben wurden, wurden Angaben zum Befall (schwach, stark) mit Kieferndrehrost und zum Vorkommen von Zitter-Pappel (Populus tremula, alternativer Wirt des Pathogens) berücksichtigt. Es wurden zwei Multi Logit - Modelle entwickelt zur Vorhersage der Gesamtwahrscheinlichkeit einer Kieferndrehrost-Schädigung sowie der Wahrscheinlichkeit einer schweren Schädigung durch den Pilz. Die Standorts- und Bestandesmerkmale wurden als erklärende Variablen verwendet. In den Modellen wurde die Restvarianz bezüglich Inventur-Erhebungsgruppe, Cluster und Jahr geprüft. Das Vorkommen von Zitter-Pappel und die Bodenfertilität waren die wichtigsten Faktoren für eine zunehmende Wahrscheinlichkeit einer Kieferndrehrost-Schädigung auf Bestandesebene. Die Schadenswahrscheinlichkeit verringerte sich mit zunehmender Temperatursumme, die für den Standort berechnet wurde. Die Gesamtschadenswahrscheinlichkeit war auf Torf- und Mineralböden gleich hoch, sofern Zitter-Pappeln im Bestand vorkamen. Ohne Zitter-Pappeln war die Schadenswahrscheinlichkeit auf Mineralböden höher. Zudem war die Gesamtschadenswahrscheinlichkeit in natürlich regenerierten Beständen niedriger als in gepflanzten oder gesäten Beständen, und sie nahm mit zunehmendem Durchschnittsalter der Kiefern ab. In beiden Modellen war die Restvarianz auf der Ebene der Inventur-Erhebungsgruppe und der Probecluster signifikant. [source] Influence of stream geomorphic condition on fish communities in Vermont, U.S.A.FRESHWATER BIOLOGY, Issue 10 2006EIKA P. SULLIVAN, S. MA Summary 1. Evaluations of stream geomorphic condition may increase our understanding of the composite effects of human-induced habitat change on fish communities. Using systematic sampling of 44 reaches spread across 26 rivers in Vermont from 2002 through 2004, we tested the hypothesis that stream reaches in reference geomorphic condition would support fish assemblages that differed in diversity and productivity from fish communities found in reaches of poorer geomorphic condition. 2. At each study reach, we sampled the fish community, identified the morphological unit according to common stream classification systems and then evaluated the extent of deviation from reference geomorphic condition using a regionally adapted geomorphic assessment methodology. 3. We used principal component analysis (PCA) and linear regression to build exploratory models linking stream geomorphic condition to fish community characteristics. 4. Our results suggest that geomorphic condition significantly influences fish community diversity, productivity and condition. Geomorphic condition was a significant factor in all of our fish community models. In conjunction with additional reach characteristics, geomorphic condition explained up to 31% of the total variance observed in models for species diversity of fish communities, 44% of the variance in assemblage biomass and 45% of the variance in a regional index of biotic integrity. 5. Our work builds on single-species evidence that geomorphic characteristics represent important local-scale fish-habitat variables, showing that stream geomorphic condition is a dominant factor affecting entire fish communities. Our results enhance our understanding of the hierarchy of factors that influences fish community diversity and organisation and support the use of geomorphic condition assessments in stream management. [source] Online end-to-end quality of service monitoring for service level agreement managementINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 4 2008Xiaoyuan Ta Abstract A major challenge in network and service level agreement (SLA) management is to provide Quality of Service (QoS) demanded by heterogeneous network applications. Online QoS monitoring plays an important role in the process by providing objective measurements that can be used for improving network design, troubleshooting and management. Online QoS monitoring becomes increasingly difficult and complex due to the rapid expansion of the Internet and the dramatic increase in the speed of network. Sampling techniques have been explored as a means to reduce the difficulty and complexity of measurement. In this paper, we investigate several major sampling techniques, i.e. systematic sampling, simple random sampling and stratified sampling. Performance analysis is conducted on these techniques. It is shown that stratified sampling with optimum allocation has the best performance. However, stratified sampling with optimum allocation requires additional statistics usually not available for real-time applications. An adaptive stratified sampling algorithm is proposed to solve the problem. Both theoretical analysis and simulation show that the proposed adaptive stratified sampling algorithm outperforms other sampling techniques and achieves a performance comparable to stratified sampling with optimum allocation. A QoS monitoring software using the aforementioned sampling techniques is designed and tested in various real networks. Copyright © 2007 John Wiley & Sons, Ltd. [source] A standardized and reliable method to apply the Global Assessment of Functioning (GAF) scale to psychiatric case recordsINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 2 2000Dr M. Mirandola Abstract The Global Assessment of Functioning (GAF) scale is widely used both in routine clinical practice and in research. However, its reliability has never been assessed when used to rate information in clinical records. The present study focuses on the development of a standardized method (an ongoing modelling process between raters) for establishing desired levels of inter-rater reliability (IRR) in the application of the GAF to psychiatric case records. Fifty-one patients at first-ever contact with mental health services were included in the study. They were selected from a total sample of 662 first-ever patients by using a systematic sampling. Three raters (resident psychiatrists at their third year of training) took part in a 12-hour training programme, during which they were asked to assess the global psychological functioning of patients, taking into account information recorded in case records. The extent of agreement between raters was estimated by applying the ,limits of agreement' method and the ,concordance correlation coefficient'. The training programme proved to be feasible, easy to administer and acceptable to psychiatrists in training with limited previous experience of using rating scales. Very high levels of concordance (all greater than 0.95) emerged between the three raters. The GAF, completed using information from case records included in the initial assessment form, appeared to be a reliable instrument, even when used by clinical psychiatrists in training. Copyright © 2000 Whurr Publishers Ltd. [source] Generalizability and transferability of meta-synthesis research findingsJOURNAL OF ADVANCED NURSING, Issue 2 2010Deborah Finfgeld-Connett finfgeld-connett d. (2010) Generalizability and transferability of meta-synthesis research findings. Journal of Advanced Nursing 66(2), 246,254. Abstract Title.,Generalizability and transferability of meta-synthesis research findings. Aim., This paper is a report of a critical analysis of the generalizability and transferability of meta-synthesis research findings. Background., Findings from a large number of qualitative research investigations have had little impact on clinical practice and policy formation. Single qualitative investigations are not intended to produce findings that are directly applicable to clinical practice, simple literature reviews of qualitative studies are not conducted using sophisticated methods to develop new cumulative knowledge, and methods for systematically compiling and synthesizing qualitative findings have just recently been developed in nursing. Data sources., This analysis of qualitative review methods was based on over 10 years of meta-synthesis research experience and a non-time-limited cross-discipline search of the English-language literature related to qualitative research and generalizability. Discussion., Generalizability of meta-synthesis findings is enhanced by insuring validity through systematic sampling, second-tier triangulation, maintenance of well-documented audit trails and the development of multi-dimensional theory. Generalizability of meta-synthesis findings is tentative until successful transference to new situations takes place. Implications for nursing., Nurse researchers are urged to conduct well-designed and executed meta-synthesis investigations that have the potential to generate findings that are relevant to clinical practice and policy formation. They are also encouraged to disseminate their meta-synthesis findings skilfully and work with practitioners and policy-makers to apply and evaluate them judiciously in clinical settings. Conclusion., Qualitative meta-synthesis is a way of putting together qualitative findings from disparate investigations so that they can more readily be used in clinical practice and policy formation. [source] SKATE: A docking program that decouples systematic sampling from scoringJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 14 2010Jianwen A. Feng Abstract SKATE is a docking prototype that decouples systematic sampling from scoring. This novel approach removes any interdependence between sampling and scoring functions to achieve better sampling and, thus, improves docking accuracy. SKATE systematically samples a ligand's conformational, rotational and translational degrees of freedom, as constrained by a receptor pocket, to find sterically allowed poses. Efficient systematic sampling is achieved by pruning the combinatorial tree using aggregate assembly, discriminant analysis, adaptive sampling, radial sampling, and clustering. Because systematic sampling is decoupled from scoring, the poses generated by SKATE can be ranked by any published, or in-house, scoring function. To test the performance of SKATE, ligands from the Asetex/CDCC set, the Surflex set, and the Vertex set, a total of 266 complexes, were redocked to their respective receptors. The results show that SKATE was able to sample poses within 2 Å RMSD of the native structure for 98, 95, and 98% of the cases in the Astex/CDCC, Surflex, and Vertex sets, respectively. Cross-docking accuracy of SKATE was also assessed by docking 10 ligands to thymidine kinase and 73 ligands to cyclin-dependent kinase. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010 [source] On error prediction in circular systematic samplingJOURNAL OF MICROSCOPY, Issue 3 2006K. Ý. JÓNSDÓTTIR Summary An extended covariogram model is discussed for estimating the precision of circular systematic sampling. The extension is motivated by recent developments in shape analysis of featureless planar objects. Preliminary simulation results indicate that it is important to consider the extended covariogram model. [source] New variance expressions for systematic sampling: the filtering approachJOURNAL OF MICROSCOPY, Issue 3 2006XIMO GUAL-ARNAU Summary We present a collection of variance models for estimators obtained by geometric systematic sampling with test points, quadrats, and n -boxes in general, on a bounded domain in n -dimensional Euclidean space ,n, n = 1, 2, ... , and for systematic rays and sectors on the circle. The approach adopted , termed the filtering approach , is new and different from the current transitive approach. This report is only preliminary, however, because it includes only variance models in terms of the covariogram of the measurement function. The estimation step is in preparation. [source] Environmental risk factors for early infantile atopic dermatitisPEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 5 2007I. J. Wang Previous studies of predictors of atopic dermatitis (AD) in Asia have had limited sample size and small numbers of variables focused primarily on family history or dietary exposures. The purpose of this study was to evaluate the influence of various environmental risk factors for early infantile AD. We used multistage, stratified systematic sampling to recruit 2048 mother,child pairs from the Taiwan national birth registration in 2003. Information on environmental risk factors for infant AD gathered by questionnaire were available from 1760 infants at 6 months of age. Multiple logistic regression was used to estimate adjusted odds ratios (aORs) and their 95% confidence intervals (CIs) for risk factors for AD after adjusting for potential confounders. AD was noted in 118 of 1760 (6.7%) of the infants. After adjusting for maternal age and education, family history of atopy, infant gender, and gestational age, fungi on walls of the house [aOR 2.14 (95% CI 1.41,3.22)] and frequent use of microwave oven at home [aOR 1.71 (95% CI 1.13,2.58)] increased the risk of early infantile AD. This study suggests that environmental factors do play a role in early infantile AD. Fungi, a kind of aeroallergen, are especially important in humid climate as in Taiwan and their impacts might be felt at the early infant stage. The hazards of microwave use should be paid more attention. [source] Fatigue and associated factors in hemodialysis patients in TaiwanRESEARCH IN NURSING & HEALTH, Issue 1 2006H.E. Liu Abstract The number of patients suffering from end-stage renal disease is increasing rapidly around the world, including in Taiwan. Hemodialysis (HD) patients report fatigue as a major stressor. The purpose of this correlational study with systematic sampling was to explore fatigue and associated physiological, psychological, and situational factors in 119 Taiwanese HD patients. Results indicate that levels of fatigue were mild. Three variables (gender, employment, and depression) had a significant impact on fatigue. Some differences in physiological factors by depression, gender, and employment were found. Stepwise regressions showed that depression, age, and urea reduction ratio were significant predictors for overall fatigue and two of its dimensions. Some relationships from the theory of unpleasant symptoms were supported. © 2006 Wiley Periodicals, Inc. Res Nurs Health 29:40,50, 2006 [source] Trend estimation of financial time seriesAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 3 2010Víctor M. Guerrero Abstract We propose to decompose a financial time series into trend plus noise by means of the exponential smoothing filter. This filter produces statistically efficient estimates of the trend that can be calculated by a straightforward application of the Kalman filter. It can also be interpreted in the context of penalized least squares as a function of a smoothing constant has to be minimized by trading off fitness against smoothness of the trend. The smoothing constant is crucial to decide the degree of smoothness and the problem is how to choose it objectively. We suggest a procedure that allows the user to decide at the outset the desired percentage of smoothness and derive from it the corresponding value of that constant. A definition of smoothness is first proposed as well as an index of relative precision attributable to the smoothing element of the time series. The procedure is extended to series with different frequencies of observation, so that comparable trends can be obtained for say, daily, weekly or intraday observations of the same variable. The theoretical results are derived from an integrated moving average model of order (1, 1) underlying the statistical interpretation of the filter. Expressions of equivalent smoothing constants are derived for series generated by temporal aggregation or systematic sampling of another series. Hence, comparable trend estimates can be obtained for the same time series with different lengths, for different time series of the same length and for series with different frequencies of observation of the same variable. Copyright © 2009 John Wiley & Sons, Ltd. [source] Late Quaternary history around Nioghalvfjerdsfjorden and Jøkelbugten, North-East GreenlandBOREAS, Issue 3 2001OLE BENNIKE Nioghalvfjerdsfjorden in North-East Greenland is at present covered by a floating glacier. Raised marine deposits in the surrounding area contain shells of marine molluscs, bones of marine mammals and pieces of driftwood. A fairly systematic sampling of such material has been conducted, followed by extensive radiocarbon dating. We suggest that the Greenland ice sheet extended onto the shelf offshore North-East Greenland during isotope stage 2, perhaps even reaching the shelf break. During the subsequent recession of the ice sheet, the entrance of Nioghalvfjerdsfjorden had become ice-free by 9.7 cal. ka BP. The recession culminated between 7.7 and 4.5 cal. ka BP, during which time the fjord was glacier-free along its entire 80 km length. No dates younger than 4.5 cal. ka BP are available on marine material from the fjord, and it seems probable that the fjord has been continuously covered by the floating glacier since this time. The maximum glaciation was attained around AD 1900, after which thinning and recession took place. The marine limit increases from c. 40 m above sea level near the present margin of the Inland Ice to c. 65 m above sea level at the outer coast. These figures fit into the regional pattern of the marine limit for areas both to the south and north. The marine fauna comprise two bivalves, Macoma calcarea and Serripes groenlandicus, that may represent a southern element present during the Holocene temperature optimum. Remains of three taxa of southern extralimital terrestrial and limnic plants were dated to 5.1 cal. ka BP, and remains of another extralimital plant were dated to 8.8 and 8.5 cal. ka BP. The known Holocene time ranges of the willow Salix arctica and the lemming Dicrostonyx torquatus have been extended back to 8.8 and 6.4 cal. ka BP, respectively, providing minimum dates for their immigration to Greenland. [source] Predicting risk for early infantile atopic dermatitis by hereditary and environmental factorsBRITISH JOURNAL OF DERMATOLOGY, Issue 5 2009H-J. Wen Summary Background, Hereditary and environmental factors contribute to the occurrence of atopic dermatitis (AD). However, the interaction of these two factors is not totally understood. Objectives, To evaluate the early risk factors for infantile AD at the age of 6 months and to develop a predictive model for the development of AD. Methods, In 2005, a representative sample of mother and newborn pairs was obtained by multistage, stratified systematic sampling from the Taiwan national birth register. Information on hereditary and environmental risk factors was collected by home interview when babies were 6 months old. Multivariate regression analysis was applied to determine the risk factors for AD in the infants. Results, A total of 20 687 pairs completed the study satisfactorily. AD was diagnosed in 7·0% of 6-month-old infants by physicians. Parental asthma, atopic dermatitis and allergic rhinitis, and maternal education levels were risk factors for AD in infants. Among environmental factors, fungus on walls at home and renovation/painting in the house during pregnancy were significantly associated with early infantile AD. Using these factors, the probability of having infantile AD was estimated and grouped into low, high and very high. With five runs of tests in mutually exclusive subsets of this population, the likelihood of AD for 6-month-old infants was consistent in all the groups with the predictive model. The highest predicted probability of AD was 70·1%, among boys with maternal education levels > 12 years, both parents with AD, renovation and painting of the house during pregnancy and fungus on walls at home. The lowest probability was 3·1%, among girls with none of the above factors. Conclusions, This investigation provides a technique for predicting the risk of infantile AD based on hereditary and environmental factors, which could be used for developing a preventive strategy against AD, especially among those children with a family history of atopy. [source] | ||||||||||||||||