Summary The multivariate techniques of association, factor, and cluster analysis were applied to a set of phytosociological data obtained
from an area forming part of the salt desert shrub vegetation in southeastern Utah. Although there were certain advantages
to using more objective and quantitative means of synthesizing this vegetation data, the vegetation units obtained were highly
similar to those identified by more traditional and subjective approaches involving less effort and expense. The relative
simplicity of the vegetation and landscape concerned probably influence these conclusions. Arguments for multivariate analyses
are probably stronger where there exists more cryptic and complex interrelationships of vegetation to environment
Zusammenfassung Auf pflanzensoziologische Daten aus cinem Gebiet, das ein Teil der Salzsteppen-Strauchvegetation im süd?stlichen Utah ist,
wurden die Multifaktoren-Verfahren der Assoziations-, Faktoren-, und “Cluster” (H?ufungs-gruppen)-Analyse angewendet. Zwar
war es in manchem vorteilhaften, objektivere und quantitative Mittel für die Synthese diesen Vegetationsdaten zu verwenden.
Aber, die so erhaltenen Vegetationseinheiten waren doch jenen weitgchend ?hnlich, die mit geringerem Aufwand und billiger
durch mehr traditionelle und subjektive Methoden gewonnen wurden. Die relative Einfachheit dieser Vegetation und Landschaft
begünstigen wahrscheinlich diese Schlu?folgerung. Im Falle verborgenerer und komplexerer Wechselbezichungen von Vegetation
und Umwelt sind die Argumente für den Einsatz von Multifaktoren-Analysen wahrscheinlich st?rker.
Approved by the Director of the Utah Agricultural Experiment Station as Journal Paper No. 757. 相似文献
Urbanization is a major driver of biodiversity change but how it interacts with spatial and temporal gradients to influence the dynamics of plant–pollinator networks is poorly understood, especially in tropical urbanization hotspots. Here, we analysed the drivers of environmental, spatial and temporal turnover of plant–pollinator interactions (interaction β-diversity) along an urbanization gradient in Bengaluru, a South Indian megacity. The compositional turnover of plant–pollinator interactions differed more between seasons and with local urbanization intensity than with spatial distance, suggesting that seasonality and environmental filtering were more important than dispersal limitation for explaining plant–pollinator interaction β-diversity. Furthermore, urbanization amplified the seasonal dynamics of plant–pollinator interactions, with stronger temporal turnover in urban compared to rural sites, driven by greater turnover of native non-crop plant species (not managed by people). Our study demonstrates that environmental, spatial and temporal gradients interact to shape the dynamics of plant–pollinator networks and urbanization can strongly amplify these dynamics. 相似文献
Prolonged diabetes ultimately leads to Diabetic Retinopathy (DR) which is one of the leading causes of preventable blindness in the
world. Through advanced image analysis techniques are used for abnormalities detection in retina that define and correlate the
severity of DR. A thorough study is done in this area in recent past years and on the basis of these studies we have developed a
computer based prediction model that is used to determine the severity of DR. To identify severity DR, we have analyzed the
human eye image. We have extracted some important features from human eye image i.e. Blood Artery, Optical disc, Exudates.
Based on these image and data we have designed an automated system for the determination of DR severity. This automated DR
severity assessment methods can be used to predict the clinical case and conditions when young clinicians would agree or disagree
with their more experienced fellow members. The algorithms described in this study may be used in clinical practice to validate or
invalidate the diagnoses. Algorithms or method developed here may also be used for pooling diagnostic knowledge for serving
mankind. Here we have described a computational based low cost retinal diagnostic approach which can aid an ophthalmologist to
quickly diagnose the various stages of DR. This system can accept retinal images and can successfully detect any pathological
condition associated with DR. 相似文献
Since the outbreak of highly virulent coronaviruses, significant interest was assessed to the brain and heart axis (BHA) in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-affected patients. The majority of clinical reports accounted for unusual symptoms associated with SARS-CoV-2 infections which are of the neurological type, such as headache, nausea, dysgeusia, anosmia, and cerebral infarction. The SARS-CoV-2 enters the cells through the angiotensin-converting enzyme (ACE-2) receptor. Patients with prior cardiovascular disease (CVD) have a higher risk of COVID-19 infection and it has related to various cardiovascular (CV) complications. Infected patients with pre-existing CVDs are also particularly exposed to critical health outcomes. Overall, COVID-19 affected patients admitted to intensive care units (ICU) and exposed to stressful environmental constraints, featured with a cluster of neurological and CV complications. In this review, we summarized the main contributions in the literature on how SARS-CoV-2 could interfere with the BHA and its role in affecting multiorgan disorders. Specifically, the central nervous system involvement, mainly in relation to CV alterations in COVID-19-affected patients, is considered. This review also emphasizes the biomarkers and therapy options for COVID-19 patients presenting with CV problems. 相似文献
Soil communities in landscapes that are rapidly changing due to a range of anthropogenic processes can be regarded as highly transient systems where interactions between competing species or trophic levels may be seriously disrupted. In disturbed communities dispersal in space and time has a role in ensuring continuity of community function. Stable communities, in undisturbed systems, are more dependent on competition and other biotic interactions between species. We predicted how food web components would respond to disturbance, based on their dispersal and colonizing abilities. During decomposition, flows of energy and nutrients generally follow either a bacterial-based path, with bacteria as the primary decomposer and bacterial-feeding fauna and their predators forming the associated food web, or a fungal-based channel. Trophic links that were generally resistant to change were the organisms of the bacterial pathway that have high abilities to disperse in time and passively disperse in space. Organisms in the fungal pathway were less resistant to disturbance. Resource inputs to the soil system are derived from plants, either through root exudation and root turnover during active growth or from dead plant material following senescence or agricultural tillage. Disturbances to the soil system can arise as a direct action on the soil, or indirectly from effects on the above-ground plant community. Disturbance-induced changes in plant community composition will change the soil food web composition. Organisms involved in direct interactions with plants (e.g. AM-mycorrhizal fungi) were also predicted to be vulnerable to disturbance.
Zusammenfassung
Bodengemeinschaften in Landschaften, die sich aufgrund einer Reihe von anthropogenen Prozessen schnellstens verändern, können als sehr kurzlebige Systeme angesehen werden, in denen Interaktionen zwischen konkurrierenden Arten oder trophischen Leveln nachhaltig unterbrochen sind. In gestörten Gemeinschaften hat die Ausbreitung in Raum und Zeit eine Rolle bei der Wahrung der Kontinuität von Gemeinschaftsfunktionen. Stabile Gemeinschaften, in ungestörten Systemen, sind stärker von Konkurrenz und anderen biotischen Interaktionen zwischen den Arten abhängig. Wir sagten voraus, wie Nahrungsnetzkomponenten auf Störung antworten würden, basierend auf ihrer Ausbreitungs- und Kolonisationsfähigkeit. Während der Zersetzung folgen die Flüsse von Energie und Nährstoffen im Allgemeinen entweder einem Weg, der auf Bakterien basiert, mit Bakterien als den primären Zersetzern und bacterienfressender Fauna und ihre Predatoren, die das assoziierte Nahrungsnetz bilden, oder sie folgen einem Kanal, der auf Pilzen basiert. Trophische Verknüpfungen, die im Allgemeinen resistent gegen Veränderungen waren, waren die Organismen des bakteriellen Weges, die große Möglichkeiten haben sich in Zeit und passiv im Raum auszubreiten. Organismen des pilzbasierten Weges waren weniger widerstandsfähig gegenüber Störungen. Die Ressourcenzufuhr in das Bodensystem stammte von Pflanzen, entweder über Wurzelausscheidungen und/oder Wurzelturnover während des aktiven Wachstums oder von totem Pflanzenmaterial aufgrund von Seneszenz oder landwirtschatlicher Bodenbearbeitung. Störungen des Bodensystems können durch direkte Einwirkungen auf den Boden oder indirekt durch Effekte der oberirdischen Pflanzemeinschaft entstehen. Störungsinduzierte Veränderungen in der Zusammensetzung der Pflanzengemeinschaft werden die Zusammensetzung des Bodennahrungsnetzes verändern. Für Organismen, die an direkten Interaktionen mit Pflanzen beteiligt sind (beispielsweise AM-Mykorrhizapilze), wurde ebenfalls vorhergesagt, dass sie anfällig für Störungen sind. 相似文献