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961.
H. River Gates Stephen Yezerinac Abby N. Powell Pavel S. Tomkovich Olga P. Valchuk Richard B. Lanctot 《Journal of Field Ornithology》2013,84(4):389-402
Five subspecies of Dunlins (Calidris alpina) that breed in Beringia are potentially sympatric during the non‐breeding season. Studying their ecology during this period requires techniques to distinguish individuals by subspecies. Our objectives were to determine (1) if five morphometric measures (body mass, culmen, head, tarsus, and wing chord) differed between sexes and among subspecies (C. a. actites, arcticola, kistchinski, pacifica, and sakhalina), and (2) if these differences were sufficient to allow for correct classification of individuals using equations derived from discriminant function analyses. We conducted analyses using morphometric data from 10 Dunlin populations breeding in northern Russia and Alaska, USA. Univariate tests revealed significant differences between sexes in most morphometric traits of all subspecies, and discriminant function equations predicted the sex of individuals with an accuracy of 83–100% for each subspecies. We provide equations to determine sex and subspecies of individuals in mixed subspecies groups, including the (1) Western Alaska group of arcticola and pacifica (known to stage together in western Alaska) and (2) East Asia group of arcticola, actites, kistchinski, and sakhalina (known to winter together in East Asia). Equations that predict the sex of individuals in mixed groups had classification accuracies between 75% and 87%, yielding reliable classification equations. We also provide equations that predict the subspecies of individuals with an accuracy of 22–96% for different mixed subspecies groups. When the sex of individuals can be predetermined, the accuracy of these equations is increased substantially. Investigators are cautioned to consider limitations due to age and feather wear when using these equations during the non‐breeding season. These equations will allow determination of sexual and subspecies segregation in non‐breeding areas, allowing implementation of taxonomic‐specific conservation actions. 相似文献
962.
963.
In literature, an effective method enabling the classification, based on a single indicator, of habitats that need a priority protection intervention has not been identified yet. Moreover, the excessive number of landscape metrics, used to quantify integrity of habitats, can cause confusion, often providing redundant and inconsistent results.The aim of this work is to develop a method for evaluating the ecological vulnerability of the habitats in sites of high biodiversity conservation interest. In the first phase, we selected and analyzed, by using principal component analysis (PCA) and fuzzy logic, the landscape metrics, in order to obtain the map of the intrinsic ecological vulnerability index. In the second step, the result of this intrinsic vulnerability was connected, through another fuzzy model, to anthropogenic impacts, obtaining the integrated ecological vulnerability index. We developed specific spatial indicators (landscape metrics), which can examine the mutual position and morphology of the habitats present, along with indicators of human pressure, related to the type and intensity of use of the anthropic territory, with reference to the habitat itself as well as to the areas immediately adjacent. The developed fuzzy models are innovative, compared to the current ecological studies, and examine landscape metrics as well as the impact of human activities.The case study is the “Val Basento-Ferrandina Scalo” Site of Community Importance, Ferrandina-SCI (Basilicata Region, Southern Italy). The results allowed us to build a rank of the habitats based on their intrinsic and integrated ecological vulnerability. Moreover, the results show that, in the Ferrandina-SCI, the most important source of concern is not human activities, but rather the inherent risk of ecological fragility caused by geographical and landscape features of the different patches of habitats themselves.This model aims to be a tool for decision support in sustainable landscape management. It is easy to use and to apply on other regions, although it should always be accompanied by a sensitivity analysis to reduce the subjectivity. 相似文献
964.
Protein is one of the three main storage chemical components in maize grains, and is negatively correlated with starch concentration
(SC). Our objective was to analyse the influence of genetic backgrounds on QTL detection for protein concentration (PC) and
to reveal the molecular genetic associations between PC and both SC and grain weight (GWP). Two hundred and eighty-four (Pop1)
and 265 (Pop2) F2:3 families were developed from two crosses between one high-oil maize inbred GY220 and two normal maize inbreds 8984 and 8622
respectively, and were genotyped with 185 and 173 pairs of SSR markers. PC, SC and GWP were evaluated under two environments.
Composite interval mapping (CIM) and multiple interval mapping (MIM) methods were used to detect single-trait QTL for PC,
and multiple-trait QTL for PC with both SC and GWP. No common QTL were shared between the two populations for their four and
one PC QTL. Common QTL with opposite signs of effects for PC and SC/GWP were detected on three marker intervals at bins 6.07–6.08,
8.03 and 8.03–8.04. Multiple-traits QTL mapping showed that tightly-linked QTL, pleiotropic QTL and QTL having effects with
opposite directions for PC and SC/GWP were all observed in Pop1, while all QTL reflected opposite effects in Pop2. 相似文献
965.
《Animal : an international journal of animal bioscience》2018,12(12):2627-2638
This study investigates how the ecosystem services (ES) linked to livestock grazing are perceived across countries. A total of 82 case studies collected from 42 countries via survey (53.7% cases from Europe and 46.3% from outside of Europe) have been analysed through a multivariate approach. In all, 18 non-provisioning ES were considered. Overall, the reported impacts of livestock grazing on the different ES were much more positive than negative. Notably, a large proportion of respondents reported either positive or very positive impacts for some cultural ES, namely cultural, historic and natural heritage (84%), knowledge systems and educational values (77%), landscape values (74%), and for some supporting and regulating ES, namely habitat provision (66%), nutrient cycling (65%), and bush encroachment/fire control (66%). Based on multiple regression analysis, geographic origin, stakeholder type and species category, as well as protection status of the grazing area, had significant effects on the perception of the impacts. Respondents reported those impacts as more positive in Europe, in protected areas and where several species were present in the grazing area. A significantly larger proportion of respondents reported recognition of ES provided by the grazing livestock population in European countries (40.9%) compared with non-European countries (23.7%). Based on the survey responses it appears that in non-European countries absence of formal recognition, especially by policy makers, is a major challenge for the continued provision of ES in grazing systems. In Europe, where such recognition is already often included in legislation, the long-term sustainability of related policies and incentives to provide such services is viewed as a major issue by the respondents. 相似文献
966.
Marzieh Taghipour Shamsollah Ayoubi Hossein Khademi 《Soil & Sediment Contamination》2011,20(8):921-937
Heavy metals’ origin, accumulation, and distribution in soil have been the focus of much attention by many researchers. The objective of this study was to recognize the sources of heavy metals in surface soils in Hamadan Province in western Iran using multivariate geostatistical techniques. A total of 263 surface (0–10 cm) soil samples and 18 rock samples from major parent materials were collected. Cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) contents of the samples were determined. Selected soil physical and chemical characteristics were also measured. A multivariate geostatistical analysis was performed to identify the common source of heavy metals. The quantities of Co, Cr, and Ni were found to be associated with parent rocks, corresponding to the first factor termed the “lithologic component.” The second factor was mainly attributed to Cu, which also comprised the first and third factors, indicating a mixed source both from lithologic and anthropogenic inputs. Zn and Pb contents were related to the anthropogenic activities and comprised the third factor. A significant correlation was found between metals from the lithogenic sources and selected soil properties such as soil organic matter, clay, CEC, and carbonate, indicating an interaction among them. Generally, Zn and Pb showed a less significant correlation with soil properties. 相似文献
967.
Ajay Kumar Tiwari Kavita Kumari Neeraj Nath Tiwari Pradeep Kumar Akil Ahmad Khan 《Archives Of Phytopathology And Plant Protection》2013,46(17-20):931-935
During the survey of two successive years 2012–2013, in nearby places of Gorakhpur districts, Uttar Pradesh, India, Arundo donax plants were found to be exhibiting witches’ broom, excessive branching accompanied with little leaf symptoms with considerable disease incidence. Nested PCR carried out with universal primers pair R16F2n/R16R2 employing the PCR (P1/P7) product as a template DNA (1:20) resulted in expected size positive amplification ~1.2 kb in all symptom-bearing plants suggested the association of phytoplasma with witches’ broom disease of Narkat plants. BLASTn analysis of the 16S rRNA gene sequence showed the highest (99%) sequence identity with Candidatus phytoplasma asteris (16SrI group). In phylogenetic analysis, the sequence data showed close relationships with the members of 16SrI phytoplasma and clustered within a single clade of 16SrI group and closed to B subgroup representatives. This is a first report of 16Sr I-B group phytoplasma associated with witches’ broom accompanied with little leaf disease of Narkat in India. 相似文献
968.
Eleni Panousopoulou Richard A. Tyson Till Bretschneider Jeremy B.A. Green 《Developmental biology》2013
Convergent extension (CE) is a conserved morphogenetic movement that drives axial lengthening of the primary body axis and depends on the planar cell polarity (PCP) pathway. In Drosophila epithelia, a polarised subcellular accumulation of PCP core components, such as Dishevelled (Dvl) protein, is associated with PCP function. Dvl has long been thought to accumulate in the mediolateral protrusions in Xenopus chordamesoderm cells undergoing CE. Here we present a quantitative analysis of Dvl intracellular localisation in Xenopus chordamesoderm cells. We find that, surprisingly, accumulations previously observed at mediolateral protrusions of chordamesodermal cells are not protrusion-specific but reflect yolk-free cytoplasm and are quantitatively matched by the distribution of the cytoplasm-filling lineage marker dextran. However, separating cell cortex-associated from bulk Dvl signal reveals a statistical enrichment of Dvl in notochord–somite boundary-(NSB)-directed protrusions, which is dependent upon NSB proximity. Dvl puncta were also observed, but only upon elevated overexpression. These puncta showed no statistically significant spatial bias, in contrast to the strongly posteriorly-enriched GFP-Dvl puncta previously reported in zebrafish. We propose that Dvl distribution is more subtle and dynamic than previously appreciated and that in vertebrate mesoderm it reflects processes other than protrusion as such. 相似文献
969.
Ecological assessment requires the integration of many physical, chemical, and/or biological quality elements. The choice of the aggregation method of such partial assessments into an overall assessment can considerably affect the assessment outcome – an issue that has been controversially discussed within the scientific community for the last decade. Current practice often considers only two different aggregation methods, the weighted arithmetic mean (additive aggregation) and the one-out, all-out method (minimum aggregation). However, both have important drawbacks. Additive aggregation compensates a bad status of one quality element by a number of elements featuring good status. Minimum aggregation can lead to overly pessimistic assessment results, since only the quality element in the worst status is considered. Here, we introduce a toolbox containing current and new aggregation methods, demonstrate and discuss their properties with simple, didactical examples, and suggest in which situations best to use them. Then, we illustrate the consequences of selected aggregation schemes for ecological river assessment with the case study of the Swiss Modular Concept of stream assessment (SMC), which we apply to ten river reaches in the Mönchaltdorfer Aa catchment in Switzerland. To be able to do so, we used multi-criteria decision analysis, i.e., multi-attribute value theory, to arrange the SMC quality elements into an objectives hierarchy, and to translate their individual assessments into value functions. Our case study revealed that choosing the most appropriate aggregation method particularly matters, if objectives with significantly different qualities are aggregated. We argue that redundant objectives (i.e., quality elements), often found at the lower levels of the objectives hierarchy, should best be aggregated additively allowing for compensation to increase the statistical significance of the results. Further, we suggest that complementary sub-objectives that often occur at higher levels may be optimally aggregated with a mixture of additive and minimum aggregation. Such a mixed method will allow some compensation, but nevertheless penalize for very bad states. Since here we compare commonly used aggregation methods with some which we believe have never been discussed in an assessment context before, our study concurrently informs ecological assessment in theory and in practice. 相似文献
970.
Brian A. Blanksby Graeme A. Wood Leonard Freedman 《American journal of physical anthropology》1981,24(Z2):75-100
This paper discusses kinesiological aspects of human locomotion in terms of the incomplete morphological adaptation of the body to current lifestyles. Modern instrumentation used for biomechanical analyses is outlined for the most part in the context of human running. Investigations of spatiotemporal and segmental measures by electronic walkways, photography, optoelectronics and angle-angle diagrams are referred to, as is electromyography and direct force measurement. Three commonly identifiable areas of applied kinesiological research, namely sport, industry and medicine, are considered with reference to the prevention, treatment and after-care of injuries whether received on the sporting field, in the work place, or in an automobile accident. 相似文献