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Messina V.,CONICET | Messina V.,National Council for Scientific and Technical Research | Sance M.,University of Bucharest | Grigioni G.,Food Technology Institute | And 3 more authors.
IEEE Sensors Journal | Year: 2014

Response of metal-oxide sensors based on tin dioxide SnO2 (P and T) and chromium titanium oxide, and on tungsten oxide (LY) were used to analyze different cultivars of garlic scapes. Temperature and time for sample incubation were set at two temperatures (40 °C and 50 °C) and at two incubation times (6 and 10 min). All the sensors presented saturation at 50 °C. A temperature set at 40 °C had optimal responses for all the sensors. Conditions established in the first place (40 °C during 6-min incubation) were used to evaluate five types of different cultivars of fresh garlic scape in order to evaluate sensors. Linear discrimant analysis with Wilks' lambda stepwise method was applied to investigate the grouping of garlic scapes as a function of the ultivar. Two discriminant functions (DF1 and DF2) were obtained that explained 93.7% and 5% of the total variance, respectively. On the other hand, the same cultivars were analyzed among storage (three days). Data showed that changes among storage could be detected by LY, T, and P sensors among each cultivar (LY and T for Sureño; L for Castaño; P for Gostoso; LY, P, and T for Fuego and P for Morado). Differences among odor are related to the amount of volatile compounds (allicins and sulfide compounds) present, which are presumed to be responsible for their distinct flavors and aromas in each cultivar. © 2014 IEEE.

PubMed | National Council for Scientific and Technical Research
Type: Journal Article | Journal: Chemosphere | Year: 2012

Contamination of aquatic systems is a major environmental stress that can interfere with predator-prey interactions, altering prey or predator behavior differentially. We determined toxicity parameters of the fungicide trifloxystrobin (TFS) and examined its effects on predation rate, using a fish predator (Synbranchus marmoratus) and four anuran tadpole species as prey (Rhinella arenarum, Physalaemus santafecinus, Leptodactylus latrans, and Elachistocleis bicolor). TFS was not equally toxic to the four tadpole species, E. bicolor being the most sensitive species, followed by P. santafecinus, R. arenarum, and L. latrans. Predation rates were evaluated using different treatments that combined predator and prey exposed or not to this fungicide. TFS would alter the outcome of eel-tadpole interaction by reducing prey movements; thus, prey detection would decrease and therefore tadpole survival would increase. In addition, eels preyed selectively upon non-exposed tadpoles avoiding the exposed ones almost all throughout the period evaluated. Predation rate differed among prey species; such differences were not due to TFS exposure, but to interspecific differences in behavior. The mechanism that would explain TFS-induced reduction in predation rates remains unclear; however, what is clear is that sublethal TFS concentrations have the potential to alter prey behavior, thereby indirectly altering predator-prey interactions. In addition, we consider that predator-prey relationships are measurable responses of toxicant exposure and provide ecological insight into how contaminants modify predator-prey interactions.

PubMed | National Council for Scientific and Technical Research
Type: Journal Article | Journal: Archives of environmental contamination and toxicology | Year: 2011

In this study, amphibian tadpoles Rhinella arenarum were exposed to different concentrations of Roundup Ultra-Max (ULT), Infosato (INF), Glifoglex, and C-K YUYOS FAV. Tadpoles were exposed to these commercial formulations with glyphosate (CF-GLY) at the following concentrations (acid equivalent [ae]): 0 (control), 1.85, 3.75, 7.5, 15, 30, 60, 120, and 240mg ae/L for 6-48h (short-term). Acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carboxylesterase (CbE), and glutathione S-transferase (GST) activities were measured among tadpoles sampled from those treatments that displayed survival rates >85%. Forty-eight-hour LC(50) for R. arenarum tadpoles exposed to CF-GLY in the static tests ranged from ULT=2.42 to FAV=77.52mg ae/L. For all CF-GLY, the LC(50) values stabilized at 24h of exposure. Tadpoles exposed to all CF-GLY concentrations at 48h showed decreases in the activities of AChE (control=17.502.23nmol/min/mg/protein; maximum inhibition INF 30mg ae/L, 71.52%), BChE (control=6.310.86nmol/min/mg/protein; maximum inhibition INF 15mg ae/L, 78.84%), CbE (control=4.390.46nmol/min/mg/protein; maximum inhibition INF 15mg ae/L, 81.18%), and GST (control=4.860.49nmol/min/mg/protein; maximum inhibition INF 1.87mg ae/L, 86.12%). These results indicate that CF-GLY produce a wide range of toxicities and that all enzymatic parameters tested may be good early indicators of herbicide contamination in R. arenarum tadpoles.

News Article | November 25, 2016
Site: www.newscientist.com

The media tends to interpret culture in yearly cycles. Critics publish end-of-year best-of lists and Oxford Dictionaries just selected “post-truth” as its word of the year. But the words we use actually seem to operate on a 14-year cycle, an analysis has found. Marcelo Montemurro at the University of Manchester, UK, and Damián Zanette at Argentina’s National Council for Scientific and Technical Research identified 5630 commonly used nouns and analysed how their popularity changed over the last three centuries. To do this, they wrote computer scripts to dig through Google Ngram, a database of the words used in nearly five million digitised books. They then ranked the nouns in order of popularity and tracked how their rankings changed from 1700 to 2008. A curious pattern emerged. They found that English words rose in popularity and then fell out of favour in cycles of about 14 years, although cycles over the past century have tended to be a year or two longer. They also found evidence of cycles of this length in French, German, Italian, Russian and Spanish. The popularity of related nouns – such as king, queen and duchess – tended to rise and fall together over time. Some cycles appear to coincide with historical events. For example, large swaths of words declined in popularity in the years around the world wars. Although the reason for this is unclear, Montemurro thinks it could be related to political trends. These results support previous work that suggests that language evolves in a patterned way, similar to the way genes are transmitted from parent to offspring, says Mark Pagel at the University of Reading, UK. “Language is not all over the place,” he says. “It’s remarkably consistent.” However, Pagel says the researchers still need to completely rule out these cycles being a statistical fluke. “It’s fascinating to look for cultural factors that might affect this, but we also expect certain periodicities from random fluctuations,” he says. “Now and then, a word like ‘apple’ is going to be written more, and its popularity will go up. But then it’ll fall back to a long-term average.” However, if something does lie behind the cycle, its 14-year duration is puzzling. Some baby names have been found to move in and out of popularity over roughly the length of a human generation. But with nouns, Pagel doesn’t see an obvious cultural connection. “It doesn’t fit the human life history,” he says. “There’s no particular reason why it should be 14 years.” Montemurro admits that the significance of the cycle’s length remains unclear, but he thinks this is due to more than chance. “It’s very difficult to imagine a random phenomenon that will give you this pattern,” he says. And he thinks that further study of the cycle could reveal insights about human behaviour and the nature of fashion and trends. “Assuming these patterns reflect some cultural dynamics, I hope this develops into better understanding of why we change the topics we discuss,” Montemurro says. “We might learn why writers get tired of the same thing and choose something new.”

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