Fermentation-derived Aroma Compounds in Varietal Young Wines from South Africa

The volatile composition of 925 single cultivar young Sauvignon blanc, Chardonnay, Pinotage, Merlot, Shirazand Cabernet Sauvignon wines of vintages 2005 to 2007, was determined using gas chromatography – flameionisation detection. Compositional data were compared to published data on young wines from South Africa andother countries. South African young wines analysed in this study had a largely similar volatile composition tothat reported in the literature. Significant between-vintage and between-cultivar differences were observed in thevolatile composition of the wines investigated in this study. The concentration ranges of four compounds in redwines, hexanol, propanol, diethyl succinate and ethyl lactate, and four compounds in white wines, 2-phenylethanol,hexanoic acid, isoamyl acetate and propanol, were not influenced by vintage effects. This finding was interpretedas the first indication that typical concentration ranges for some aroma compounds can be established for SouthAfrican young cultivar wines. A trend was observed in the white wines that the alcohols and their respective acetateesters, as well as fatty acids and their ethyl esters, were responsible for the vintage-related effects. Differences involatile composition between Chardonnay and Sauvignon blanc wines could also largely be explained on the samebasis. Classification models were established to discriminate between individual red wine cultivars and between thetwo white wine cultivars and correct classification rates of respectively, 79 % and 85 % were achieved

Quantitative Survey of 3-alkyl-2-methoxypyrazines and First Confirmation of 3-ethyl-2-methoxypyrazine in South African Sauvignon blanc Wines

3-Alkyl-2-methoxypyrazines are important aroma components in Sauvignon blanc wine, contributing tothe typical vegetative character associated with the cultivar. The analysis of methoxypyrazines is highlychallenging and, as a result, limited quantitative data are available for South African Sauvignon blancwines. In this study, liquid chromatography-tandem mass spectrometry was applied for the sensitivequantification of the three principal methoxypyrazines in 881 South African Sauvignon blanc wines. Thetotal wine methoxypyrazine concentration exceeded the combined recognition threshold for the vegetativearoma in more than 60% of the samples, demonstrating the involvement of these compounds in the typicalaroma of the cultivar. The analytical method was adapted to allow the accurate quantitation and spectralconfirmation of 3-ethyl-2-methoxypyrazine in Sauvignon blanc wines for the first time. Concentrationsranged between 1.1 and 4.9 ng/L. Statistically significant relationships between wine methoxypyrazineconcentrations and parameters related to the maturity of the grapes and to the climate, as well asgeographical origin and vintage, were found

Changes in the own group bias across immediate and delayed recognition tasks

Face recognition is biased in favour of in-group identity, particularly strongly for race or ethnicity but to some extent also for sex and age. This ‘own group bias’ (OGB) can have profound implications in practical settings, with incorrect identification of black suspects by white witnesses constituting 40% of criminal exonerations investigated by the Innocence Project. Although authors have offered several explanations for the OGB in face recognition, there is little consensus, apart from the acknowledgement that the bias must reflect perceptual learning history. One matter that is not currently clear is whether the bias occurs at encoding, or at retrieval from memory. We report an experiment designed to tease out bias at encoding, versus bias at retrieval. Black and white South African participants encoded 16 target faces of both the same and other race and gender, and attempted immediately afterward to match the target faces to members of photograph arrays that either contained or did not contain the targets. After a further delay, they attempted to identify the faces they had encoded from memory. Results showed a strong crossover OGB in the delayed matching task, but an asymmetrical OGB at retrieval (only white participants showed the OGB). Further investigation of recognition performance, considering only images correctly matched in the delayed matching task, showed a narrowly non-significant OGB at retrieval, but the investigation was likely not sufficiently powered to discover the effect, if it exists. Significance: • We demonstrate the presence of a crossover OGB in face recognition in a sample of black and white South Africans in a delayed matching task (a measure of encoding). • Our findings show that the OGB may change rapidly. In the present study, the OGB took a crossover form at retrieval immediately after encoding, but was asymmetrical when assessed shortly afterwards. • We used a novel approach for disentangling effects at encoding and at retrieval, but do not provide clear evidence to distinguish whether the OGB is a failure of encoding or of memory retrieval

InterFace : A software package for face image warping, averaging, and principal components analysis

We describe InterFace, a software package for research in face recognition. The package supports image warping, reshaping, averaging of multiple face images, and morphing between faces. It also supports principal components analysis (PCA) of face images, along with tools for exploring the “face space” produced by PCA. The package uses a simple graphical user interface, allowing users to perform these sophisticated image manipulations without any need for programming knowledge. The program is available for download in the form of an app, which requires that users also have access to the (freely available) MATLAB Runtime environment

Applied screening tests for the detection of superior face recognition.

In recent years there has been growing interest in the identification of people with superior face recognition skills, for both theoretical and applied investigations. These individuals have mostly been identified via their performance on a single attempt at a tightly controlled test of face memory-the long form of the Cambridge Face Memory Test (CFMT+). The consistency of their skills over a range of tests, particularly those replicating more applied policing scenarios, has yet to be examined systematically. The current investigation screened 200 people who believed they have superior face recognition skills, using the CFMT+ and three new, more applied tests (measuring face memory, face matching and composite-face identification in a crowd). Of the sample, 59.5% showed at least some consistency in superior face recognition performance, although only five individuals outperformed controls on overall indices of target-present and target-absent trials. Only one participant outperformed controls on the Crowds test, suggesting that some applied face recognition tasks require very specific skills. In conclusion, future screening protocols need to be suitably thorough to test for consistency in performance, and to allow different types of superior performer to be detected from the outset. Screening for optimal performers may sometimes need to directly replicate the task in question, taking into account target-present and target-absent performance. Self-selection alone is not a reliable means of identifying those at the top end of the face recognition spectrum

Volatile fingerprinting differentiates diverse-aged craft beers

Supplementary data to this article can be found online at https:// doi.org/10.1016/j.lwt.2019.03.044.Beer ageing on wood is a complex and difficult to control process involving several reactions and compounds. Difficulties in understanding the underlying phenomena often lead to empirical and unpredictable processes and heterogeneous products. This work resorts to volatile fingerprinting along with multivariate analysis as tools to differentiate and highlight differences in beers derived from diverse production processes. Volatile composition of beers originating from barrel ageing processes and unaged beer were analyzed by GC-MS. The collected data was processed by principal component analysis, which allowed the evaluation of relations between samples and volatile compounds. Beers were distinguished by clusters comprising different groups of volatiles. Beer with the longest period in barrel was in the cluster with the most volatiles. Beer produced by resident barrel microbiota fermentation was characterized by presence of Brettanomyces sp. metabolites. Beer aged in barrel by a shorter time period showed characteristic content of ethyl esters and oak extractives. Beer produced in inox vat and beer fermented in barrel with pitching of S. cerevisiae appeared in the same cluster, relating with fermentative esters. Volatile fingerprinting was a viable approach to characterize and distinguish the analyzed beers, providing relevant information regarding the impact of production methodologies in volatile composition.This work had funding support of the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit and COMPETE 2020 (POCI-01-0145 FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by the European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte. Fermentum –EngenhariadasFermentações Lda.also participated incofunding and supplying materials for this work. Authors would like to thank Mr. Paulo Coutinho and Quinta do Portal for supplying the oak barrels used in this work.info:eu-repo/semantics/publishedVersio

Individual differences in eyewitness accuracy across multiple lineups of faces

Theories of face recognition in cognitive psychology stipulate that the hallmark of accurate identification is the ability to recognize a person consistently, across different encounters. In this study, we apply this reasoning to eyewitness identification by assessing the recognition of the same target person repeatedly, over six successive lineups. Such repeat identifications are challenging and can be performed only by a proportion of individuals, both when a target exhibits limited and more substantial variability in appearance across lineups (Experiments 1 and 2). The ability to do so correlates with individual differences in identification accuracy on two established tests of unfamiliar face recognition (Experiment 3). This indicates that most observers have limited facial representations of target persons in eyewitness scenarios, which do not allow for robust identification in most individuals, partly due to limitations in their ability to recognize unfamiliar faces. In turn, these findings suggest that consistency of responses across multiple lineups of faces could be applied to assess which individuals are accurate eyewitnesses

Extreme enrichment of Se, Te, PGE and Au in Cu sulfide microdroplets: evidence from LA-ICP-MS analysis of sulfides in the Skaergaard Intrusion, east Greenland

The Platinova Reef, in the Skaergaard Intrusion, east Greenland, is an example of a magmatic Cu–PGE–Au sulfide deposit formed in the latter stages of magmatic differentiation. As is characteristic with such deposits, it contains a low volume of sulfide, displays peak metal offsets and is Cu rich but Ni poor. However, even for such deposits, the Platinova Reef contains extremely low volumes of sulfide and the highest Pd and Au tenor sulfides of any magmatic ore deposit. Here, we present the first LA-ICP-MS analyses of sulfide microdroplets from the Platinova Reef, which show that they have the highest Se concentrations (up to 1200 ppm) and lowest S/Se ratios (190–700) of any known magmatic sulfide deposit and have significant Te enrichment. In addition, where sulfide volume increases, there is a change from high Pd-tenor microdroplets trapped in situ to larger, low tenor sulfides. The transition between these two sulfide regimes is marked by sharp peaks in Au, and then Te concentration, followed by a wider peak in Se, which gradually decreases with height. Mineralogical evidence implies that there is no significant post-magmatic hydrothermal S loss and that the metal profiles are essentially a function of magmatic processes. We propose that to generate these extreme precious and semimetal contents, the sulfides must have formed from an anomalously metal-rich package of magma, possibly formed via the dissolution of a previously PGE-enriched sulfide. Other processes such as kinetic diffusion may have also occurred alongside this to produce the ultra-high tenors. The characteristic metal offset pattern observed is largely controlled by partitioning effects, producing offset peaks in the order Pt+Pd>Au>Te>Se>Cu that are entirely consistent with published D values. This study confirms that extreme enrichment in sulfide droplets can occur in closed-system layered intrusions in situ, but this will characteristically form ore deposits that are so low in sulfide that they do not conform to conventional deposit models for Cu–Ni–PGE sulfides which require very high R factors, and settling of sulfide liquids

Research capacity building in Africa as part of international programmes: Experience gained from the Kaapvaal Craton Project

The international Kaapvaal Craton project was used to provide extensive training and human resource capacity building within the South African geoscience research community. This report discusses the mechanisms of recruitment, success rates and outcomes of the southern African students specifically, as well as the positive aspects and shortcomings of the protocol that was followed. Suggestions are offered to improve future programmes of this nature