Vowel allophony in Ness Gaelic: Phonetic and phonological patterns of laxing and retraction

The vowel system of the dialect of Scottish Gaelic spoken in Ness, Lewis differs from that of other dialects in several important ways. In particular, several vowels display patterns of allophony that have not been investigated instrumentally and, in some cases, have not been reported before for Scottish Gaelic. This paper documents the Ness system in detail, focusing in particular on the tense–lax opposition in /i e/ and retraction of /a(ː)/ next to velarised consonants. The results of a traditional linguistic fieldwork study are presented first, followed by a detailed acoustic study of nine speakers. The acoustic reality of these allophonic patterns, reflected in F1 and F2 values, is verified statistically using LME modelling. Bimodality in the distribution of tokens in acoustic space, confirmed statistically with Hartigan’s Dip Test, is taken as evidence for the existence of discrete phonological categories (Bermúdez-Otero & Trousdale 2011). It is found that speakers vary as to whether these allophonic oppositions are restricted to the phonetic grammar, or have undergone stabilisation and advanced into the categorical phonology (Bermúdez-Otero 2007, 2015). It is observed that laxing of /i e/ in Ness Gaelic occurs in exactly those contexts where there is a direct transition between the vowel and a following supra-glottal consonant. It is therefore proposed that this tense–lax opposition is grounded in conflicting strategies of contrast enhancement, whereby laxing increases the perceptual distinctiveness of a following consonant by allowing for more distinctive formant transitions, at the expense of the distinctiveness of the vowel itself (Storme 2019).

Susceptibility of Euschistus heros and Dichelops furcatus (Hemiptera: Pentatomidae) to Selected Insecticides in Brazil

Euschistus heros (Fabricius, 1798) and Dichelops furcatus (Fabricius, 1775) are key pests of agricultural crops in Brazil. Chemical insecticides are the main control tactic used against these species. Here, we investigated the susceptibility of E. heros and D. furcatus from distinct regions to the mains insecticides used to stink bugs control in Brazil. Field populations of these species were collected throughout the 2017–2019 crop seasons and insects were exposed to insecticides in dip-test bioassays using fresh green bean pods. Populations of E. heros exhibited low variation in the susceptibility to acephate (LC50 = 172.2 to 1,008 µg a.i. per ml), and thiamethoxam (LC50 = 28.8 to 433.9 µg a.i. per ml); resistance ratios were less than 5.9- and 15.1-fold, respectively. In contrast, these populations had higher variation in the susceptibility to bifenthrin (LC50 = 26.7 to 636.1 µg a.i. per ml) and lambda-cyhalothrin (LC50 = 10.0 to 636.1 µg a.i. per ml); resistance ratios reaching 23.8- and 63.6-fold, respectively. Susceptibility monitoring data indicated a higher susceptibility of E. heros to the manufacturers field-recommended rates of acephate, lambda-cyhalothrin + thiamethoxam, and bifenthrin + acetamiprid than lambda-cyhalothrin. Populations of D. furcatus exhibited low variation in the susceptibility to acephate (LC50 = 219.2 to 614.1 µg a.i. per ml), bifenthrin (LC50 = 62.8 to 197.4 µg a.i. per ml), and lambda-cyhalothrin (LC50 = 189.5 to 2,538 µg a.i. per ml); resistance ratios were less than 13.4-fold. In summary, populations of E. heros are less susceptible to pyrethroids, while populations of D. furcatus have similar susceptibility to the insecticides evaluated.

Corrosion and wear analysis of HVOLF sprayed WC-10CO-4Cr coating on geothermal turbine blade

Purpose The purpose of this paper is to develop the high pressure high-velocity oxy-liquid fuel sprayed WC-10Co-4Cr coatings on geothermal turbine 9Cr-1Mo steel for protection against wear and corrosion. Design/methodology/approach The microstructural characterization of as-deposited and corroded coating was done and presented using X-ray diffraction and scanning electron microscope/energy dispersive spectroscopy analysis. Findings The developed coating offered 50 per cent enhanced microhardness (1,200 HV) and 100 per cent enhanced wear resistance, in comparison to bare geothermal turbine steel, respectively. The coating has shown enhanced life in the simulated working conditions (fog test and dip test). This may be because of the high microhardness of the developed coating as per the proven tribological theories. Originality/value Coating offered excellent corrosion resistance in the harsher simulated environments to geothermal turbines.

Analysis of free chlorine in aqueous solution at very low concentration with lateral flow tests

Test strips are convenient tools for rapid, semi-quantitative analysis of a variety of parameters by dipping them for a few seconds in a sample solution followed by a simple colorimetric read-out. Their sensitivity is mainly determined by the reactivity of the test dyes on the reaction zone and is not sufficient for some applications. The detection limit of commercially available free chlorine test strips, for example, is at present not low enough to confirm the absence of this analyte as disinfectant in rinsing solutions after disinfection or to control required residual amounts of chlorine in drinking water. Therefore, we developed a user-friendly lateral flow test which is capable to detect very low amounts of free chlorine. The latter relies on a larger sample volume passing the reaction zone as compared to simple dip test strips. An amount of as low as 0.05 ppm chlorine can, however, only be detected if oxidation stable flow test substrates are used. The eventually developed flow test reaches a 10x higher sensitivity than a commercial dip test. The result is obtained within 4–5 min flow time, whereby no action is required by the user during this analysis time.