Reassessing the role of the honeybee (Apis mellifera) Dufour's gland in egg marking

Dufour's gland secretion may allow worker honeybees to discriminate between queen-laid and worker-laid eggs. To investigate this, we combined the chemical analysis of individually treated eggs with an egg removal bioassay. We partitioned queen Dufour's gland into hydrocarbon and ester fractions. The bioassay showed that worker-laid eggs treated with either whole gland extract, ester fraction or synthetic gland esters were removed more slowly than untreated worker-laid eggs. However, the effect only lasted up to 20 h. Worker-laid eggs treated with the hydrocarbon fraction were removed at the same rate as untreated eggs. The amount of ester which reduced the egg removal rate was far higher than that naturally found on queen-laid or worker-laid eggs, and at natural ester levels no effect was found. Our results indicate that esters or hydrocarbons probably do not function as the signal by which eggs can be discriminated.     

Foraminiferal proxies for pollution monitoring in moderately polluted harbors

Benthic foraminifera are increasingly used as environmental bio-indicators, especially in polluted environments where their sensitivity to pollutants may be expressed by a modification of the assemblages. Eighteen sediment samples were collected in September 2000 in five harbors located in moderately polluted estuaries on the coast of Vendée (France) for the study of foraminiferal assemblages. Ten heavy metals and 13 PAH have been analyzed from the sediments. The marine to continental estuarine gradient has a prevalent influence on the foraminiferal distribution. However, the results show that foraminiferal density and species richness of the assemblages decrease with an increase in heavy metal and PAH concentration, and therefore may be used as pollution indicators. Moreover, the more polluted areas are dominated by the tolerant pioneer species Haynesina germanica that may be used as bio-indicator of pollution, mainly in the uppermost areas.     

Fuzzy clustering analysis of the first 10 MEIC chemicals

In this paper, we discuss the classification results of the toxicological responses of 32 in vivo and in vitro test systems to the first 10 MEIC chemicals. In this order we have used different fuzzy clustering algorithms, namely hierarchical fuzzy clustering, hierarchical and horizontal fuzzy characteristics clustering and a new clustering technique, namely fuzzy hierarchical cross-classification. The characteristics clustering technique produces fuzzy partitions of the characteristics (chemicals) involved and thus it is a useful tool for studying the (dis)similarities between different chemicals and for essential chemicals selection. The cross-classification algorithm produces not only a fuzzy partition of the test systems analyzed, but also a fuzzy partition of the considered 10 MEIC (multicentre evaluation of in vitro cytotoxicity) chemicals. In this way it is possible to identify which chemicals are responsible for the similarities or differences observed between different groups of test systems. In another way, there is a specific sensitivity of a chemical for one or more toxicological tests.     

Role of esters in egg removal behaviour in honeybee (Apis mellifera) colonies

In queen-right honeybee colonies workers detect and eat the vast majority of worker-laid eggs, a behaviour known as worker policing. However, if a colony becomes permanently queen-less then up to 25% of the worker population develops their ovaries and lay eggs, which are normally reared into a final batch of males. Ovary development in workers is accompanied by changes in the chemical secretion of the Dufour's gland with the production of queen-like esters. We show that ester production increases with the period that the colony is queen-less. The increased ester production also corresponds to an increase in persistence of worker-laid eggs in queen-right colonies, since the esters somehow mask the eggs true identity. However, in a rare queen-less colony phenotype, workers always eat eggs indiscriminately. We found that the egg-laying workers in these colonies were unusual in that they were unable to produce esters. This apparently maladaptive egg eating behaviour is also seen in queen-less colonies prior to the appearance of egg-laying workers, a period when esters are also absent. However, the indiscriminate egg eating behaviour stops with the appearance of ester-producing egg-laying workers. These observations suggest that esters are providing some contextual information, which affects the egg eating behaviour of the workers.     

Optimization of fuel briquette production from cassava peels,plantain peels and corn cobs

Journal of Material Cycles and Waste Management - Mechanical properties enable to handle storage and transport of fuel briquette. Binder is key element of these mechanical properties. Biobinder is...     

Associations between urinary cadmium levels,blood pressure,and hypertension: the ESTEBAN survey

Environmental Science and Pollution Research - Cadmium is inconsistently associated with blood pressure (BP) and hypertension. Our study focuses to understand the association between urinary...     

Global gap analysis of cactus species and priority sites for their conservation

Knowing how much biodiversity is captured by protected areas (PAs) is important to meeting country commitments to international conservation agreements, such as the Convention on Biological Diversity, and analyzing gaps in species coverage by PAs contributes greatly to improved locating of new PAs and conservation of species. Regardless of their importance, global gap analyses have been conducted only for a few taxonomic groups (e.g., mangroves, corals, amphibians, birds, mammals). We conducted the first global gap analysis for a complete specious plant group, the highly threatened Cactaceae. Using geographic distribution data of 1438 cactus species, we assessed how well the current PA network represents them. We also systematically identified priority areas for conservation of cactus species that met and failed to meet conservation targets accounting for their conservation status. There were 261 species with no coverage by PAs (gap species). A greater percentage of cacti species (18%) lacked protection than mammals (9.7%) and birds (5.6%), and also a greater percentage of threatened cacti species (32%) were outside protected areas than amphibians (26.5%), birds (19.9%), or mammals (16%). The top 17% of the landscape that best captured covered species represented on average 52.9% of species ranges. The priority areas for gap species and the unprotected portion of the ranges of species that only partially met their conservation target (i.e., partial gap) captured on average 75.2% of their ranges, of which 100 were threatened gap species. These findings and knowledge of the threats affecting species provide information that can be used to improve planning for cacti conservation and highlight the importance of assessing the representation of major groups, such as plants, in PAs to determining the performance of the current PA network.     

Quantification of advective solute travel times and mass transport through hydrological catchments

This study has investigated and outlined the possible quantification and mapping of the distributions of advective solute travel times through hydrological catchments. These distributions are essential for understanding how local water flow and solute transport and attenuation processes affect the catchment-scale transport of solute, for instance with regard to biogeochemical cycling, contamination persistence and water quality. The spatial and statistical distributions of advective travel times have been quantified based on reported hydrological flow and mass-transport modeling results for two coastal Swedish catchments. The results show that the combined travel time distributions for the groundwater-stream network continuum in these catchments depend largely on the groundwater system and model representation, in particular regarding the spatial variability of groundwater hydraulic parameters (conductivity, porosity and gradient), and the possible contributions of slower/deeper groundwater flow components. Model assumptions about the spatial variability of groundwater hydraulic properties can thus greatly affect model results of catchment-scale solute spreading. The importance of advective travel time variability for the total mass delivery of naturally attenuated solute (tracer, nutrient, pollutant) from a catchment to its downstream water recipient depends on the product of catchment-average physical travel time and attenuation rate.     

Planning waste cooking oil collection systems

This research has been motivated by a real-life problem of a waste cooking oil collection system characterized by the existence of multiple depots with an outsourced vehicle fleet, where the collection routes have to be plan. The routing problem addressed allows open routes between depots, i.e., all routes start at one depot but can end at the same or at a different one, depending on what minimizes the objective function considered. Such problem is referred as a Multi-Depot Vehicle Routing Problem with Mixed Closed and Open Inter-Depot Routes and is, in this paper, modeled through a mixed integer linear programming (MILP) formulation where capacity and duration constraints are taken into account. The model developed is applied to the real case study providing, as final results, the vehicle routes planning where a decrease of 13% on mileage and 11% on fleet hiring cost are achieved, when comparing with the current company solution.     

Prenatal foetal diagnosis of partial trisomy 3q and monosomy 13p due to a maternal balanced rearrangement

The authors describe a case of a male foetus whose ultrasound at 20 weeks' gestation revealed cystic hygroma, cleft lip and ventricular septal defect. Amniotic fluid cytogenetics using GTG banding showed a 46,XY,der(13)t(3;13)(q12;p11.1) rearrangement, and fluorescence in situ hybridization (FISH) delineated the relevant breakpoints. Familial studies identified a maternal balanced translocation involving chromosomes 3 and 13. The post-mortem examination confirmed the prenatal ultrasound findings. Copyright © 2005 John Wiley & Sons, Ltd.