EVALUATION OF PANELIST PERFORMANCE IN DESCRIPTIVE PROFILING OF RANCID SAUSAGES: A MULTIVARIATE STUDY

This paper illustrates an application of principal component analysis (PCA), partial least squares regression (PLS) and generalized procrustes analysis (GPA) to evaluate the ability of a trained group of assessors to perceive rancidity in foods. PCA and regression PLS were utilized to determine to which extent sensory attributes capture the information perceived by a trained sensory panel, and if this can be developed into a predictive model for rancidity in sausages. The data were submitted to a GPA to obtain a map of the products for each subject as compared with a consensus products map. Assessors plots for the sensory attributes were also obtained to reveal the dissimilarities between panelists and to explore clustering.     

DISSIMILARITIES IN COGNITION OF FLAVOUR TERMS RELATED TO VARIOUS SENSORY LABORATORIES IN A MULTIVARIATE STUDY

A study of dissimilarities in cognitive perception of 20 common flavor terms was carried out by the Sensory Group of Norway. An average cognitive pattern of the flavor terms was revealed from multidimensional scaling (MDS) and cluster analysis (CLU). In general, small but interesting deviations between different sensory laboratories working with various food products were found by a multivariate pattern recognition technique based on principal component analysis (PCA). Suggestions for finding general reference standards for flavor terms are discussed.     

THE SIGNIFICANCE OF KLEPTOPARASITISM DURING THE BREEDING SEASON IN A COLONY OF ARCTIC SKUAS STERCORARIUS PARASITICUS IN ICELAND

Breeding and kleptoparasitism of Arctic Skuas was studied at Vik, Iceland, in 1973. Hatching success was 88.9%; fledging success was 0.27 fledglings per pair. The heavy chick mortality occurred mostly in the first week after hatching. In the early part of the breeding season skuas fed by robbing kittiwakes of their food at sea and by eating arthropods at the breeding grounds. At the time of hatching of skua eggs, which coincided with the hatching of Puffin eggs, skuas switched their feeding activities to kleptoparasitism of Puffins and fish so obtained was the principal item of most skuas' diet thereafter. In the first week post-hatching, the energy balance of an average adult skua pirating Puffins was estimated to be negative, but changed to positive a week later, although later, coinciding with an influx of non-breeders it turned back to negative. Arctic Terns which normally breed at Vik, and are exploited by skuas, failed to breed in 1973, and the abnormally heavy chick loss is therefore attributed to this failure of the terns. The success of the skuas kleptoparasitizing Puffins depends on the proximity of the interactions to the cliff or to the ocean, where Puffins seck refuge. Skuas catch fish mostly in the air, especially if it is dropped from high. Fish dropped from low is mostly taken by competing gulls and Ravens, which mostly control the ground and lower airspace. Skuas chasing in groups enhance their success, but the average success per member decreased with group increase. However, the success of the group-member in the ‘best’ position was equal to that of a single skua. Puffins carry 1 (large)-6 (smaller) fish, an approximately equal load irrespective of number of fish. Skuas preferentially chase Puffins carrying ‘large’ fish, thus maximizing their yield per effort. Arctic Skuas responded to changes in the numbers of arriving Puffins with a functional response, but their monitoring of the food supply was far from perfect.     

hybridlab (version 1.0): a program for generating simulated hybrids from population samples

We present the computer program hybridlab 1.0 for simulating intraspecific hybrids from population samples of nuclear genetic markers such as microsatellites, allozymes or SNPs (single nucleotide polymorphisms). The program generates a user‐specified number of multilocus F1 hybrid genotypes between any pair of potentially hybridizing populations included in a standard input‐file of multilocus genotypes for population genetic analysis. This simple, user‐friendly program has a wide range of applications for studying natural and artificial hybridization; in particular, for evaluating the statistical power for individual assignment of parental and hybrid individuals. An example of application for Atlantic cod populations is given.     

21st century climate change threatens mountain flora unequally across Europe

Continental‐scale assessments of 21st century global impacts of climate change on biodiversity have forecasted range contractions for many species. These coarse resolution studies are, however, of limited relevance for projecting risks to biodiversity in mountain systems, where pronounced microclimatic variation could allow species to persist locally, and are ill‐suited for assessment of species‐specific threat in particular regions. Here, we assess the impacts of climate change on 2632 plant species across all major European mountain ranges, using high‐resolution (ca. 100 m) species samples and data expressing four future climate scenarios. Projected habitat loss is greater for species distributed at higher elevations; depending on the climate scenario, we find 36–55% of alpine species, 31–51% of subalpine species and 19–46% of montane species lose more than 80% of their suitable habitat by 2070–2100. While our high‐resolution analyses consistently indicate marked levels of threat to cold‐adapted mountain florae across Europe, they also reveal unequal distribution of this threat across the various mountain ranges. Impacts on florae from regions projected to undergo increased warming accompanied by decreased precipitation, such as the Pyrenees and the Eastern Austrian Alps, will likely be greater than on florae in regions where the increase in temperature is less pronounced and rainfall increases concomitantly, such as in the Norwegian Scandes and the Scottish Highlands. This suggests that change in precipitation, not only warming, plays an important role in determining the potential impacts of climate change on vegetation.     

Population genomics of marine fishes: identifying adaptive variation in space and time

Studies of adaptive evolution have experienced a recent revival in population genetics of natural populations and there is currently much focus on identifying genomic signatures of selection in space and time. Insights into local adaptation, adaptive response to global change and evolutionary consequences of selective harvesting can be generated through population genomics studies, allowing the separation of the effects invoked by neutral processes (drift-migration) from those due to selection. Such knowledge is important not only for improving our basic understanding of natural as well as human-induced evolutionary processes, but also for predicting future trajectories of biodiversity and for setting conservation priorities. Marine fishes possess a number of features rendering them well suited for providing general insights into adaptive genomic evolution in natural populations. These include well-described population structures, substantial and rapidly developing genomic resources and abundant archived samples enabling temporal studies. Furthermore, superior possibilities for conducting large-scale experiments under controlled conditions, due to the economic resources provided by the large and growing aquaculture industry, hold great promise for utilizing recent technological developments. Here, we review achievements in marine fish genomics to date and highlight potential avenues for future research, which will provide both general insights into evolution in high gene flow species, as well as specific knowledge which can lead to improved management of marine organisms.