Accounting for large-scale factors in the study of understory vegetation using a conditional logistic model

Local-scale and large-scale factors can affect the presence of a species of understory vegetation in the forest. Local-scale factors may be the influence of surrounding trees, while climate and latitude are typically considered large-scale factors. A model for the presence of a species needs to take into account both scales. A conditional logistic model is proposed for those studies where only the local-scale factors are of interest and that avoids estimating the large-scale parameters. Conditioning is carried out by the number of quadrats in the plot where the vegetation is found. As the latter is a sufficient statistic for the large-scale factors, a model free from these parameters is obtained. Data gathered in the permanent sample plots of the 1985–1986 National Forest Inventory of Finland is used for illustration, where the local-scale factor of interest is the influence of the trees, quantified by an index based on the size and location of the trees. The model fitted to Vaccinium vitis-idaea showed a significant and positive influence of Scots pine on the presence of this species, while for Calamagrostis arundinacea, a decrease in the odds ratio was observed due to the influence of Norway spruce.     

不同认知风格大学生艾宾浩斯错觉的实验研究

文章以34名大学生为被试,采用2(150%,50%)×2(场独立,场依存)被试间实验设计探讨了不同认知风格大学生艾宾浩斯错觉的眼动特点。结果表明:(1)不同的认知风格对艾宾浩斯错觉判断正确量有影响,并且在眼动指标上存在差异;(2)测验成分和诱导成分之间的大小比例对艾宾浩斯错觉正确量有影响,并且在眼动指标上存在差异;(3)诱导成分和测验成分之间距离不同时对艾宾浩斯错觉正确量无显著影响,并且在眼动指标上也不存在显著差异。     

An analysis of China’s investment in the hydropower sector in the Greater Mekong Sub-Region

The Mekong River’s natural resources offer large benefits to its populations, but it also attracts the interest of foreign investors. Recently, Chinese firms, banks and government bodies have increasingly invested in large hydropower projects in the Greater Mekong Sub-Region. Due to China’s rapid economic growth, its rapid industrialisation and its limited domestic natural resources, the Chinese government has issued the ‘Going Out Strategy’ which promotes investments in overseas natural resources like water and energy resources. In search for climate-friendly low-carbon energy, cheap electricity and access to a growing market, Chinese institutions turn to Southeast Asia where Chinese institutions are currently involved in more than 50 on-going large hydropower projects as contractors, investors, regulators and financiers. These Chinese institutions have influence on environmental and social practices as well as on diplomatic and trade relations in the host countries. Currently, there are major gaps in understanding who is engaged, why, how and with what impacts. This paper therefore aims to assess the motives, actors, beneficiaries and the direct and indirect impacts of China’s investment in large hydropower projects in the Greater Mekong Sub-Region. The authors use the ‘Rising Powers Framework’ to assess these issues, which is an adapted version of the Asian Drivers Framework.     

Evolving metacommunities: toward an evolutionary perspective on metacommunities

The metacommunity framework predicts that local coexistence depends on the outcome of local species interactions and regional migration. In analogous fashion, spatial structure among populations can shape species interactions through evolutionary mechanisms. Yet, most metacommunity theories assume that populations do not evolve. Here, we evaluate how evolution shapes local species coexistence and exclusion within the multiscale and multispecies context embodied by the metacommunity framework. In general, coexistence in joint ecological-evolutionary models requires low to intermediate dispersal rates that can promote maintenance of both regional species and genetic diversity. These conditions support a set of key mechanisms that modify patterns of species coexistence including local adaptation, gene storage effects, genetic rescue effects, spatial genetic subsidies, and metacommunity evolution. Multispecies extensions indicate that correlated selection can further alter the outcome of interspecific interactions depending on the magnitude and direction of correlations and shape of fitness trade-offs. We suggest that an evolving metacommunity perspective has the potential to generate novel predictions about community structure and function by incorporating the genetic and species diversity that characterize natural communities. In adopting such a perspective, we seek to facilitate understanding about the interactions between evolutionary and metacommunity dynamics.     

Effects of cyanobacterium Fischerella ambigua isolates and cell free culture media on zebrafish (Danio rerio) embryo development

The toxic effects of several species of fresh water cyanobacteria, notably Microcystis species and associated toxins, the microcystins, Anabaena species (anatoxin), Nodularia sp. (nodularin), and Cylindrospermopsis raciborskii (cylindrospermopsin), are well known. Little, however, is known about the effects of secondary metabolites other than alkaloids. Early life stage tests with zebrafish (Danio rerio) were used to detect bioactive properties of compounds released by healthy cyanobacteria (Fischerella ambigua), particularly on the early developmental stages of fish. This approach, using F. ambigua is probably most valuable as it shows the toxicity of healthy growing cyanobacteria. The effects of cyanobacterial secondary metabolites on the embryonic stages of fish are of considerable interest as many aquatic creatures, particularly fish, are unable to avoid the potential toxins that may be released by undesirable algal blooms or as a result of allelopathic effects. In the current study, the zebrafish (D. rerio) was used as a model experimental system to investigate the effects of ambigols A and C, tjipanazole D and C, 2,4-dichlorobenzoic acid, cell free culture media, and media extracts of a terrestrial/fresh water strain of the cyanobacterium F. ambigua on embryo development. Fish embryo tests performed with the cell free culture medium showed that after 3h of exposure to undiluted culture medium all fish embryos died. At a tenfold dilution the process of epiboly (formation of the gastrula) was retarded in all embryos, lesions were observed, and their general development was significantly arrested, finally followed by death. The same tests performed with extracts (dichloromethane, n-butanol, and residual cell free culture medium) of the cell free culture medium, ambigol A, ambigol C, 2,4-dichlorobenzoic acid and tjipanazole D showed only ambigol A to have an influence on zebrafish development at concentrations>or=1 mg/l (2.06 microM). After 55 h all embryos showed pectoral oedema, irregularly shaped fin folds, bent tails, and unusual circular neoplasms in the dorsal tail fin fold. Due to the high concentration of ambigol A used in this assay these effects were considered to be of minor importance when compared to those of the culture medium.     

HEAVY METAL DISTRIBUTION AND SPECIATION IN THE NORTHERN ADRIATIC SEA

In the present study the concentrations of cobalt, copper, iron, manganese, zinc were analysed and the speciation of copper and zinc performed, with a summer and winter sampling, for two areas in the Northern Adriatic Sea and crossing at the farthest zones of the Po river-sea water interface. Results show that when salinity increases the concentrations of all investigated metals (with the exception of cobalt) present some degree of biogeochemical cycling. Copper is the element whose dissolved phase has the highest importance in metal transport across the salinity gradient. Results of speciation analysis demonstrate that the presence of excess amounts (5-8 fold) of unbound ligands confers a buffering capacity for potential inputs of dissolved metals into the Northern Adriatic Sea. The speciation of both copper and zinc in the dissolved phase was dominated by organic complexation.     

Soils and sediments of the Thua Thien-Hue Province (central Vietnam): recognizing trace element sources and the likely influence of natural events

Trace element concentrations have been measured in soil and sediment samples taken from the Thua Thien Hue (TT-H) Province and the Tam Giang-Cau Hai (TG-CH) Lagoon in 2002 and 2004. Results show that the lagoon is only slightly contaminated by elements such as Ag, Cd, Cr, Cu, Ni, Pb and Zn, whereas As, probably naturally enriched in this Asian region, reaches values above the lowest internationally accepted sediment quality guidelines. Concentrations in soils are ascribable to natural sources and distributions in the TG-CH Lagoon are mainly influenced by river inputs, with Ag and Cd undergoing estuarine desorption processes. However, concentration-depth profiles of most trace elements in sediments show a recent increasing trend that might be linked to the economic development of the area. The comparison of porosity and (210)Pb depth profiles (confirmed also by Cd and As) from repeated samplings of the same core locations in the TG-CH Lagoon seems to account for a loss of 5-10 cm of surficial sediment that took place during the time interval between the two samplings. It is hypothesized that extreme meteorological events (e.g. a major typhoon that hit the area in November 2003) could be responsible for such sediment displacement.     

COVID-19 pandemic: environmental and social factors influencing the spread of SARS-CoV-2 in São Paulo,Brazil

Environmental Science and Pollution Research - The new coronavirus SARS-CoV-2 has infected more than 14 million people worldwide so far. Brazil is currently the second leading country in number of...