GreekLex 2: a comprehensive lexical database with part-of-speech, syllabic, phonological, and stress information

Databases containing lexical properties on any given orthography are crucial for psycholinguistic research. In the last ten years, a number of lexical databases have been developed for Greek. However, these lack important part-of-speech information. Furthermore, the need for alternative procedures for calculating syllabic measurements and stress information, as well as combination of several metrics to investigate linguistic properties of the Greek language are highlighted. To address these issues, we present a new extensive lexical database of Modern Greek (GreekLex 2) with part-of-speech information for each word and accurate syllabification and orthographic information predictive of stress, as well as several measurements of word similarity and phonetic information. The addition of detailed statistical information about Greek part-of-speech, syllabification, and stress neighbourhood allowed novel analyses of stress distribution within different grammatical categories and syllabic lengths to be carried out. Results showed that the statistical preponderance of stress position on the pre-final syllable that is reported for Greek language is dependent upon grammatical category. Additionally, analyses showed that a proportion higher than 90% of the tokens in the database would be stressed correctly solely by relying on stress neighbourhood information. The database and the scripts for orthographic and phonological syllabification as well as phonetic transcription are available at http://www.psychology.nottingham.ac.uk/greeklex/

Statistical learning leads to persistent memory: evidence for one-year consolidation

Statistical learning is a robust mechanism of the brain that enables the extraction of environmental patterns, which is crucial in perceptual and cognitive domains. However, the dynamical change of processes underlying long-term statistical memory formation has not been tested in an appropriately controlled design. Here we show that a memory trace acquired by statistical learning is resistant to inference as well as to forgetting after one year. Participants performed a statistical learning task and were retested one year later without further practice. The acquired statistical knowledge was resistant to interference, since after one year, participants showed similar memory performance on the previously practiced statistical structure after being tested with a new statistical structure. These results could be key to understand the stability of long-term statistical knowledge

Bioactive paper platform for colorimetric phenols detection.

Polyphenols, as food antioxidants, are of great interest due to their health benefits as they decrease the risks of cancer and coronary cardiopathy (1). Moreover they influence the quality and organoleptic characteristics of foods (2). Lastly, some neurotransmitters are phenolic compounds. Hence the need to work out a sensitive, portable and inexpensive detection methods to monitor these compounds (3). We developed a disposable paper-based bioassay for the detection of phenolic compounds; the assay was successfully applied for the determination of polyphenols in a real matrix such as wine. The colorimetric quantification of the analyte is based on an enzymatic assay. The tyrosinase enzyme has been immobilized on a filter paper by simple over-spotting with 3-methyl-2-benzothiazolinone hydrazone (MBTH), that allows the detection of phenols by forming stable colored adducts with their enzymatic oxidation products. The color intensity of the adduct (developed after 5 min of reaction) was found to increase proportionally with the increase of the phenolic substrate concentrations. Analyte detection can be achieved by eye and quantification can be simply obtained by using a camera phone and an image analysis software. The response, characteristics of the sensor were determined using l-3,4-dihydroxyphenyl-alanine (l-DOPA), an archetype substrate of tyrosinase, as the analyte. This disposable paper-based biosensor relies on a rapid and simple method, without need of sophisticated instrumentation and trained personnel and could be extremely useful in remote locations or developing countries which does not have ready access to laboratory facilities and where simple, sensitive and low cost bioassays are essentials. 1) D. Del Rio, L.G. Costa, M.E. Lean, A. Croizer. Nutr. Metab. Cardiovasc. Dis. 20 (2010) 1-6. 2) I. Ignat, I. Volf, V.I. Popa. Food Chem. 126 (2011) 1821-1835. 3) M. Arciuli, G. Palazzo, A. Gallone, A. Mallardi. Sensors & Actuators: B. Chemical (2013)In press

Measuring children’s auditory statistical learning via serial recall

Statistical learning (SL) has been a prominent focus of research in developmental and adult populations, guided by the assumption that it is a fundamental component of learning underlying higher-order cognition. In developmental populations, however, there have been recent concerns regarding the degree to which many current tasks reliably measure SL, particularly in younger children. In the current article, we present the results of two studies that measured auditory statistical learning (ASL) of linguistic stimuli in children aged 5–8 years. Children listened to 6 min of continuous syllables comprising four trisyllabic pseudowords. Following the familiarization phase, children completed (a) a two-alternative forced-choice task and (b) a serial recall task in which they repeated either target sequences embedded during familiarization or foils, manipulated for sequence length. Results showed that, although both measures consistently revealed learning at the group level, the recall task better captured learning across the full range of abilities and was more reliable at the individual level. We conclude that, as has also been demonstrated in adults, the method holds promise for future studies of individual differences in ASL of linguistic stimuli

Seasonal variations of Rana esculenta L. skin tyrosinase

Various enzymes are known to be involved in melanin biosynthesis, but the key role appertains to tyrosinase. In amphibians this enzyme displays peculiar characteristics: i) it requires an activation process; ii) its level of enzymatic activity in the animal skin changes depending on the season. In this work, by using chymotrypsin, subtilisin and SDS as putative activators, we studied the activation process of the skin pro-tyrosinase of Rana esculenta L. in different seasons over a period of two years. We found that chymotrypsin and subtilisin were able to yield an active enzyme, but not SDS. The maximum levels of tyrosinase activity were recorded in winter and the minimum in summer. We detected tyrosinase activity in the melanosomal fraction, where the enzyme form was least sensitive to proteolytic activation, probably corresponding to a "mature" tyrosinase. The enzyme forms found in the microsomal and soluble fractions were more sensitive to proteolytic activation, probably corresponding to "immature" tyrosinase. On SDS-PAGE, the tyrosinase activity assays showed a dopa-positive band at 200 kDa and a second aggregated band with a still higher molecular mass. The significance of these results in frog melanogenesis regulation is discussed

Melanogenesis in Visceral Tissues of Salmo salar. A link between Immunity and Pigment production?

The Atlantic salmon (Salmo salar L.) is an ichthyic breeding species of considerable economic importance. The accumulation of pigments in salmon visceral organs and musculature (1) adversely affects the quality of fish products and is a problem for the aquaculture industry. Moreover, a close relationship between nutrition products and human health has been widely demonstrated. Liver, spleen, kidney and other organs of lower vertebrates harbour a visceral pigment cell system with an embryonic origin that differs from that of melanocytes (2). In teleosts, melanin-containing cells, named melano-macrophages, occur in the reticulo-endothelial system and are mainly located in kidney and spleen. In these organs, the pigment content may increase in different physiological conditions and as a response to pathological and inflammatory states (2). With the aim to reveal novel functions and behaviour of the poorly understood teleost extracutaneous pigment system, we undertook the investigation of aspects of the melanogenic systems of Atlantic salmon tissues as well as of leukocyte salmon head-kidney cells (SHK-1 cells). SHK-1 cells is a long-term cell line derived from macrophages of the Atlantic salmon head-kidney (3). Using a radiometric method we demonstrated that a tyrosinase activity is present in SHK-1 cells and salmon tissues. Western blotting showed the presence of a tyrosinase protein. Moreover differing melanin-producing activities in salmon tissues were demonstrated suggesting that pigmented cells in the organs undergo a tissue-specific differentiation. These results were confirmed by a tyrosinase protein expression in lymphoid organs, also highlighted by immunohistochemical analysis. As teleosts lack lymph nodes and Peyer’s patches, the head-kidney and spleen are regarded as the most important secondary lymphoid organs (4). The detection of tyrosinase activity in lymphoid organs indicates that a link may exist between the extracutaneous pigmentary system and the immune system in salmon. The extracutaneous melanogenetic system could be used as a biomarker for the health status of farmed fishes. References: 1. Koppang, E.O., Haugarvoll, E., Hordvik, I., Aune, L., Poppe, T. (2005) Journal of Fish Diseases 28: 13-22. 2. Agius, C., Roberts, R.J. (2003) Journal of Fish Diseases 26: 499-509. 3. Dannevig, B., Falk, K., Narmork, E. (1995) Journal of General Virology 76: 1353-1359. 4. Zapata, A., Amemiya, CT. (2000) Curr Top Microbiol Immunol 248: 67-107