Do sex-changing male snails use mate choice to get a jump on their “size advantage”?

Individuals of species that change sex from male to female may gain a “size advantage” from that sex change; that is, as males become larger, they become female, thus increasing their fecundity with their size. However, males could also gain an early and different reproductive size advantage by choosing large females as mates. While male preference for large females has been observed in many dioecious species, we know little about male size preference in sex-changing species. In choice experiments, we examined whether males of two congeneric species of marine sex-changing snails, Crepidula fornicata and C. convexa, chose large females over small ones as partners. We also used choice tests to see whether males of C. fornicata, a species whose members form long-term, multi-animal stacks, would choose two females in a stack over a single female. Surprisingly, males of neither species showed a preference for large females, in spite of the documented fecundity advantage associated with large female-size. Males of C. fornicata chose slightly, but not significantly, more single females than stacks, suggesting that neither number nor size drives mate choice in these animals. Key factors that may influence this lack of size preference include long association time, the likelihood of sperm competition, and the cost of extended mate search; it may also be that sex-change itself, the very factor that creates female-biased sexual size dimorphism in these species, prevents size preference, as males may gain sufficient reproductive advantage from eventually becoming large females themselves to offset any benefit of choosing large females.     

Rendering Bio-inert Low-Density Polyethylene Amenable for Biodegradation via Fast High Throughput Reactive Extrusion Assisted Oxidation

Journal of Polymers and the Environment - An energy-efficient high throughput pre-treatment of low-density polyethylene (LDPE) using a fast, reactive extrusion (REX) assisted oxidation technique...     

Understanding the processes in a historically relevant thermal and mineral spring water by using mixing and inverse geochemical models

Environmental Geochemistry and Health - The thermal mineral water of Peñón de los Baños spa (Mexico City) has been used for over 500 years starting in pre-Hispanic times and...     

Increasing biogas production from sewage sludge anaerobic co-digestion process by adding crude glycerol from biodiesel industry

In an effort to convert waste streams to energy in a green process, glycerol from biodiesel manufacturing has been used to increase the gas production and methane content of biogas within a mesophilic anaerobic co-digestion process using primary sewage sludge. Glycerol was systematically added to the primary digester from 0% to 60% of the organic loading rate (OLR). The optimum glycerol loading range was from 25% to 60% OLR. This resulted in an 82–280% improvement in specific gas production. Following the feeding schedule described, the digesters remained balanced and healthy until inhibition was achieved at 70% glycerol OLR. This suggests that high glycerol loadings are possible if slow additions are upheld in order to allow the bacterial community to adjust properly. Waste water treatment plant operators with anaerobic digesters can use the data to increase loadings and boost biogas production to enhance energy conversion. This process provides a safe, environmentally friendly method to convert a typical waste stream to an energy stream of biogas.     

Genetic profile of overweight and obese school-age children

Obesity is associated with overproduction of free radicals that promotes genotoxicity and could be measured as micronuclei (MN) and nuclear abnormalities (NA) in buccal mucosa cells. The frequency of MN and NA in buccal mucosa cells from overweight and obesity school-age children was determined. In a cross-sectional study, four anthropometric parameters were obtained from each child and one buccal mucosa sample was collected from each child. The slides were stained with orcein and fast green and microscopically analyzed for MN and NA. Twenty overweight and obesity school-age children (7–11 years old) from three schools located at the metropolitan area of Guadalajara were selected to form three groups with 20 children each, according to the weight features as follows: (1) normal weight; (2) overweight; and (3) obesity. No marked differences were found between groups for frequency of MN and NA. Genotoxicity, as indicated by increase in binucleated (BN) cells, was found in children within both overweight and obese groups exposed to passive tobacco smoke. There was no evidence of genetic instability in overweight and obese school-age children and no associations between body weight and genotoxicity markers found.     

Identification and quantification of 19 pharmaceutical active compounds and metabolites in hospital wastewater in Cameroon using LC/QQQ and LC/Q-TOF

Human pharmaceutical residues are a serious environmental concern. They have been reported to have eco, geno, and human toxic effects, and thus their importance as micropollutants cannot be ignored. These have been studied extensively in Europe and North America. However, African countries are still lagging behind in research on these micropollutants. In this study, the wastewaters of the University Teaching Hospital of Yaoundé (UTHY) were screened for the presence of active pharmaceutical ingredients and their metabolites. The screening was carried out using two methods: high-performance liquid chromatography coupled to a triple quadrupole analyzer (LC/QQQ) and high-performance coupled to a mass spectrometer with a time of flight analyzer (LC/Q-TOF). A total of 19 active pharmaceutical ingredients and metabolites were identified and quantified. The compounds identified include paracetamol (211.93 μg/L), ibuprofen (141 μg/L), tramadol (76 μg/L), O-demethyltramadol (141 μg/L), erythromycinanhydrate (7 μg/L), ciprofloxacin (24 μg/L), clarinthromycine (0.088 μg/L), azitromycine (0.39 μg/L), sulfamethoxazole 0.16 μg/L), trimetoprime (0.27 μg/L), caffeine (5.8 μg/L), carnamaeepine (0.94 μg/L), atenolol (0.43 μg/L), propranolol (0.3 μg/L), cimetidine (34 μg/L), hydroxy omeprazole (5 μg/L), diphenhydramine (0.38 μg/L), metformine (154 μg/L), and sucralose (13.07 μg/L).