Anaerobic decolorization of an azo dye by a mixed culture

Wool dyeing wastewater contains xenobiotic compounds that can be removed by biotechnological processes. Studies on various dyes showed that anaerobic processes are suitable to alter azo dyes as a first step of the biodegradation process. These compounds are reduced by anaerobic consortia to aromatic amines and its ultimate degradation can be achieved by a further aerobic treatment.

Studies on degradation rate of an wool acid dye were performed in batch systems inoculated with anaerobic biomass. A commercial diazo dye, Acid Red 73, was added to the synthetic medium in which glucose was used as sole carbon source.

Results indicated that the Acid Red 73 was partially degraded by a mixed culture of anaerobic bacteria and a decolorization of 90% was obtained. Kinetics studies on removal of the colour showed that the decolorization rate was several times faster than the degradation rate of glucose for a range of dye concentrations between 60 mg/L and 400 mg/L. A first order kinetic model was used for dye concentrations up to 200 mg/L. For higher concentrations a model similar to the Michaelis‐Menten equation was better fitted to the experimental data.     

Green fuel production: processes applied to microalgae

The continuous increase in world energy demand will lead to an energy crisis due to the limited availability of fossil fuels. Furthermore, the use of this energetic resource is responsible for the accumulation of greenhouse gases in atmosphere that is associated with several negative effects on environment. Therefore, it is worth to search for different energy supplies that are renewable and environmentally friendly—carbon neutral fuel. Microalgae are photosynthetic microorganisms that can achieve high oil contents. This oil is suitable for producing biodiesel; thus, microalgae are considered a promising sustainable energetic resource that can reduce the dependence on fossil fuel. Biodiesel production from microalgae includes several steps, such as cell cultivation and harvesting, oil extraction and biodiesel synthesis. Although several attempts have been made to improve biodiesel yields from microalgae, further studies are required to improve biodiesel production rates and to reduce the associated costs. This review shows the recent developments on biodiesel production from microalgae, emphasizing two process concepts: (1) indirect route, in which, after a facultative cell wall disruption method, microalgal oil is recovered in an appropriate solvent and then converted into biodiesel through transesterification and (2) direct route, in which biodiesel is produced directly from the harvested biomass. High biodiesel yields are obtained when both routes are preceded by a cell wall disruption method. In the indirect route, it is possible to apply three different types of solvents to recover microalgal oil. Although there are several concerns about the application of organic solvents, the most promising and cost-effective alternative for lipid recovery is n-hexane. Comparing direct and indirect routes, this study demonstrates that although further studies are required to optimize biodiesel production from microalgae, the available information proposes that the direct route is the most efficient.     

An approach to simulate wind fields around an urban environment for wind energy application

This work proposes an approach to simulate wind flow fields around an urban environment with the aim of evaluating the potential impact of buildings on the general wind patterns and power production using the current generation of commercial wind turbines. The simulation process was performed with the aid of accessible computational tools that can potentially render the proposed procedure applicable in other cases of interest. The roughness of the urban environment was defined as the association of roughness map, topography, and an alternative process for obtaining the volumetry of buildings. A case study was conducted in a region located at the district of Boa Viagem (Recife-PE) for assessing the applicability of the approach. Scenarios were designed in order to simulate wind flow patterns and pre-identify sites that have suitable wind energy potential for electric power production by investigating the combination of wind speed magnitude and turbulence intensity. From the results obtained, it was possible to identify zones of potential wind sources that are not detected in classical wind atlas probably due to the influence of the built environment on local wind flow patterns.     

A new quantitative analysis of ovarian development in echinoderms: the maturity stage index

This study developed an objective quantitative method for detecting small-scale temporal or spatial differences in gametogenesis in echinoderms. The method was applied to conventional monthly samples of the planktotrophic brittle star, Ophiopholis aculeata, collected at a single site in Newfoundland (eastern Canada) at 10–15 m depth. The samples were analysed to determine gonad index, oocyte size and gonadal stage using histology. The maturity stage index (MSI) was developed to integrate a measure of brittle star size (disc diameter), oocyte size and oocyte density. The MSIs ranged from 0 to 800 and had significantly different means among the four gametogenic stages (early growth, growth, mature and spent). The MSI was more sensitive in revealing significant differences between consecutive stages than any of its individual constituents. The MSI was also applied to gametogenic data from the lecithotrophic holothuroid, Mesothuria lactea, again revealing significant differences between successive oogenic stages. This method is expected to be useful in field and experimental studies of gametogenesis in echinoderms (and possibly other taxa), where it is important to detect not just the timing of annual peaks in reproduction but small differences in reproductive status among individuals or populations (e.g. from different habitats or feeding regimes).     

Arsenic (As), antimony (Sb), and lead (Pb) availability from Au-mine Technosols: a case study of transfer to natural vegetation cover in temperate climates

Soils from old Au-mine tailings (La Petite Faye, France) were investigated in relation to the natural vegetation cover to evaluate the risk of metals and metalloids (Pb, As, Sb) mobilizing and their potential transfer to native plants (Graminea, Betula pendula, Pteridium aquilinum, Equisetum telmateia). The soils are classified as Technosols with high contamination levels of As, Pb, and Sb. The single selective extractions tested to evaluate available fraction (CaCl₂, acetic acid, A-Rhizo, and DTPA) showed low labile fractions (<5 % of bulk soil contents), but still significant levels were observed (up to 342.6 and 391.9 mg/kg for As and Pb, respectively) due to the high contamination levels of soils. Even at high soil contaminations (considered as phytotoxic levels for plants), translocation factors for native plants studied are very low resulting in low concentrations of As, Sb, and Pb in their aerial part tissues. This study demonstrates the important role of (1) native plant cover in terms of “stabilization” of these contaminants, and (2) the poor effectiveness of extraction procedures used for this type of soil assemblages, i.e., rich in specific mineral phases.     

Will Evolving Climate Conditions Increase the Risk of Floods of the Large U.S.‐Canada Transboundary Richelieu River Basin?

In spring 2011, an unprecedented flood hit the complex eastern United States (U.S.)–Canada transboundary Lake Champlain–Richelieu River (LCRR) Basin, destructing properties and inducing negative impacts on agriculture and fish habitats. The damages, covered by the Governments of Canada and the U.S., were estimated to C$90M. This natural disaster motivated the study of mitigation measures to prevent such disasters from reoccurring. When evaluating flood risks, long‐term evolving climate change should be taken into account to adopt mitigation measures that will remain relevant in the future. To assess the impacts of climate change on flood risks of the LCRR basin, three bias‐corrected multi‐resolution ensembles of climate projections for two greenhouse gas concentration scenarios were used to force a state‐of‐the‐art, high‐resolution, distributed hydrological model. The analysis of the hydrological simulations indicates that the 20‐year return period flood (corresponding to a medium flood) should decrease between 8% and 35% for the end of the 21st Century (2070–2099) time horizon and for the high‐emission scenario representative concentration pathway (RCP) 8.5. The reduction in flood risks is explained by a decrease in snow accumulation and an increase in evapotranspiration expected with the future warming of the region. Nevertheless, due to the large climate inter‐annual variability, short‐term flood probabilities should remain similar to those experienced in the recent past.     

Nonapeptide levels in male cleaner fish brains during interactions with unfamiliar intra and interspecific partners

Behavioral Ecology and Sociobiology - A growing body of research suggests that songs are an important part of the courtship behavior of many bat species, however there is little information on the...     

Synchronized breeding events in sympatric marine invertebrates: role of behavior and fine temporal windows in maintaining reproductive isolation

While breeding synchrony among conspecifics is increasingly well understood with regards to the reproductive success of vertebrate and invertebrate taxa, the occurrence of simultaneous multispecies breeding events remains intriguing. The fairly recent discovery of mass annual spawnings in reef corals has provided a first glimpse at putative strategies of reproductive isolation during such events. However, the mechanisms and advantages of same-day heterospecific breeding are still poorly understood and have not yet been investigated in non-coral taxa with different life history strategies. In an effort to bridge this gap, we investigated spawning periodicity and synchrony among 26 sympatric species of free-spawning, capsule-laying, and brood-protecting macroinvertebrates belonging to six different phyla. Twenty-four of these species released gametes or larvae between early March and late April. We analyzed the events over fine temporal scales to test the hypothesis that breeding activities were not random in time or relative to each other. We found that the two main reproductive pulses followed a lunar periodicity and that consistent species- and gender-specific modulations in the timing of spawning occurred during same-day episodes involving up to six free-spawning species. Mass spawning accounts from the literature were reviewed and compared. This work suggests that many species participate in synchronous heterospecific spawning events either because they respond to the same environmental cues or rely on cross-cueing and that reproductive isolation is favored by species-specific circadian patterns, spawning behaviors and cross-gender signaling.     

Internal cohesion and geometric shape of spatial clusters

The geographic delineation of irregularly shaped spatial clusters is an ill defined problem. Whenever the spatial scan statistic is used, some kind of penalty correction needs to be used to avoid clusters’ excessive irregularity and consequent reduction of power of detection. Geometric compactness and non-connectivity regularity functions have been recently proposed as corrections. We present a novel internal cohesion regularity function based on the graph topology to penalize the presence of weak links in candidate clusters. Weak links are defined as relatively unpopulated regions within a cluster, such that their removal disconnects it. By applying this weak link cohesion function, the most geographically meaningful clusters are sifted through the immense set of possible irregularly shaped candidate cluster solutions. A multi-objective genetic algorithm (MGA) has been proposed recently to compute the Pareto-sets of clusters solutions, employing Kulldorff’s spatial scan statistic and the geometric correction as objective functions. We propose novel MGAs to maximize the spatial scan, the cohesion function and the geometric function, or combinations of these functions. Numerical tests show that our proposed MGAs has high power to detect elongated clusters, and present good sensitivity and positive predictive value. The statistical significance of the clusters in the Pareto-set are estimated through Monte Carlo simulations. Our method distinguishes clearly those geographically inadequate clusters which are worse from both geometric and internal cohesion viewpoints. Besides, a certain degree of irregularity of shape is allowed provided that it does not impact internal cohesion. Our method has better power of detection for clusters satisfying those requirements. We propose a more robust definition of spatial cluster using these concepts.