Appetite,metabolism and growth regulation in Atlantic salmon (Salmo salar L.) exposed to hypoxia at elevated seawater temperature

High temperature combined with low dissolved oxygen (DO) is one of the most challenging environmental conditions farmed fish experience; thus, understanding their impact on growth regulation is of relevance to cultured and wild populations. This study examines appetite‐ and growth‐regulating mechanisms in Atlantic salmon postsmolt exposed to either high (HO) or low oxygen (LO) at a suboptimally high temperature (17°C). Additionally, the effects of high (HE) and low (LE) dietary energy (DE) were examined. After a month of treatment, analyses of hormones, regulating appetite (ghrelin) and growth (growth hormone receptor ghr1 and insulin‐like growth factor IGF‐1), and free amino acids (FAA) were measured pre‐ and postprandially at ?4, ?2, 0, 2, 4 and 6 h. No preprandial ghrelin peaks were detected despite a significant reduction in feed intake and growth under hypoxia compared to normoxia. LO treatment also had an overall negative effect on survival compared to HO, while nutrient retention efficiency, FCR and plasma FAA concentrations were unaffected (P > 0.05). Feeding HE diet resulted in increased growth (+17%) and improved FCR (?14%) and energy retention efficiency (+26%) independent of DO. Plasma FAA concentrations were unaffected by LO treatment and DE (P > 0.05). Growth regulatory gene expressions possibly reflect an overall lower growth at a high temperature overriding the impacts of DO and DE. This study also indicates that optimal adaptation time to environmental conditions and feeding regime is crucial for establishing a regular hormonal appetite signalling that reflects real feeding anticipation in salmon.     

Phenology, damage and parasitoids of the apple leaf cutter Coenorhinus pauxillus (Germ.) (Col.: Attelabidae)

An outbreak on apple permitted a closer look at Coenorhinus pauxillus (Germar) (Col.: Attelabidae). The adult weevils emerge from mid-March onwards and attack the first unfolding leaves. Infested leaves drop when the larvae are in the 1^st or 2^nd instar, and it takes a further 4 weeks before the larvae are ready to pupate. Rearing of field-collected eggs and larvae is described. Leaf decomposition is an essential condition for pupation, as the fully-grown larvae do not leave their mine actively. Part of the population pupates more or less immediately and produces adult weevils in autumn. However, up to 70?% of the weevils remain in prolonged diapause; their pupation does not take place before the summer of the following year. Damage by the weevil involves not only the loss of leaves of flower clusters and shoots, but also feeding damage to young fruits. Two parasitoids were found. Observations indicate that 3?–?4 subsequently more abundant generations of Anaphes brachygaster Debauche (Hym.: Mymaridae) develop in eggs of C. pauxillus. Probles brevicornis Horstmann (Hym.: Ichneumonidae, Tersilochinae) emerges in May and oviposits in young weevil larvae on the tree. The parasitoid does not develop into a pupa until its host starts pupating. The outbreak of apple leaf cutter did not decline over three years, but did not spread into adjacent plantings.     

Making Asian students,making students Asian: The racialisation of export education in Auckland,New Zealand

Abstract: In recent years, international education has become a source of considerable political, academic and media debate in New Zealand. This is nowhere more the case than with regards to Auckland, the New Zealand city that has hosted the greatest number of international students. This paper focuses on the media debates around international students in Auckland with particular emphasis on the representations of the largest group of international students, those who originate from countries within the North‐East Asian region. The media representations of these students have fixed a diverse group of individuals within a singular racial identity that is known by stereotypical economic, cultural and social characteristics. As a result, these representations have further problematised the interaction between international students and the host population in Auckland while simultaneously implicating a cohort of young New Zealand citizens and permanent residents who are of similar descent within the same discourses. This process of othering the Asian student, regardless of citizenship, has consequences not simply for the practice of exporting education in this city but also for the future of a multicultural Auckland and New Zealand.     

RAPD variation within and among populations of globe artichoke cultivar 'Spinoso sardo'

Globe artichoke is a vegetable native to the Mediterranean basin. Its commercial production is mainly based on perennial cultivation of vegetatively propagated clones, which are highly heterozygous and segregate widely when progeny‐tested. The aim of this study was to measure genetic variation using random amplified polymorphic DNA (RAPD) in five populations of ‘Spinoso sardo’, the most widely grown and economically important cultivar in Sardinia (Italy). Analysis of molecular variance (amova ) gave highly significant differences between populations (28.1% of the total genetic diversity); substantial within‐population variation was detected (71.8% of total genetic diversity). The RAPD results show the need to apply clonal selection to narrow the broad genetic variability within the cultivar and to address important questions on the most suitable strategies for germplasm preservation.     

The origin of polyploids via 2n gametes in Vaccinium section Cyanococcus

Summary The production of 2n pollen (pollen with the sporophytic chromosome number) was evaluated in 4x and 6x taxa of Vaccinium section Cyanococcus. Mean frequencies of 2n pollen producers were 17.1% and 8.3% in natural 4x and 6x populations, respectively. The frequency of 2n pollen producers in the 4x species ranged from 8.6% (V. angustifolium) to 23.8% (V. pallidum). Level of 2n pollen production was genotypically variable (1% to 37.4%). The widespread occurrence of 2n pollen in 2x, 4x and 6x taxa suggests that sexual polyploidization was widespread and responsible for the origin of the polyploid species found in this genus. The frequency of 2n pollen producers was not significantly different between the 4x species and their putative 2x ancestors. These results support the origin of 4x and 6x taxa as a consequence of sexual polyploidization. Polyploids derived from sexual polyploidization would be expected to have increased fitness and flexibility due to the mode of 2n pollen formation. In blueberry species the predominant mode of 2n pollen formation is genetically equivalent to a first division restitution mechanism (FDR). FDR 2n pollen transmits a high percentage of the heterozygosity and a large fraction of the epistasis from the 2x parent to the 4x offspring.     

Coriander essential oil composition from two genotypes grown in different environmental conditions

The objective was to study the essential oil composition of coriander fruits in plants growing in environments differing in soil conditions and weediness level. Factorial field experiments were conducted in two locations from the Rolling Pampas, Argentina, and two coriander landraces (European and Argentinean) were tested under two levels of nitrogen fertilization and weediness. Data were evaluated with uni- and multivariate techniques. The variation in the oil composition was related to the relative proportion of the constituents and not to the presence/absence of a particular component. Weather conditions in 1997 favored linalool and camphor in both landraces. Location, fertilization, and weediness also affected the chemical profile. The European landrace showed a more stable concentration of the major components than the Argentinean landrace. These results, which show the relationships between some environmental conditions and the essential oil composition, are useful in the development of innovative strategies aimed to improve oil composition and to manage crop pests.     

Interrill and rill erodibility in the northern Andean Highlands

There is a lack of quantitative information describing the physical processes causing soil erosion in the Andean Highlands, especially those related to interrill and rill erodibility factors. To assess how susceptible are soils to erosion in this region, field measurements of interrill (Ki) and rill (Kr) erodibility factors were evaluated. These values were compared against two equations used by the Water Erosion Prediction Project (WEPP), and also compared against the Universal Soil Loss Equation (USLE) erodibility factor. Ki observed in situ ranged from 1.9 to 56 × 10⁵ kg s m^− 4 whereas Kr ranged from 0.3 to 14 × 10^− 3 s m^− 1. Sand, clay, silt, very fine sand and organic matter fractions were determined in order to apply WEPP and USLE procedures. Most of the evaluated soils had low erodibility values. However, the estimated USLE K values were in the low range of erodibility values. Stepwise multiple regression analyses were applied to ascertain the influence of the independent soil parameters on the Ki and Kr values. After this, we yield two empirical equations to estimate Ki and Kr under this Andean Highlands conditions. Ki was estimated using as predictors silt and very fine sand, while Kr used as predictors clay, very fine sand and organic matter content. Relationship among Ki, Kr and K are described for the Highland Andean soils.     

Serum thyroxine concentrations in clinically healthy pet guinea pigs (Cavia porcellus)

Background: Guinea pigs (Cavia porcellus) are often presented as patients in veterinary practice. Nevertheless, only limited information is available about endocrine diseases or thyroxine reference values for the species. Objective: The aim of this study was to determine serum thyroxine concentrations in a well‐defined population of clinically healthy pet guinea pigs. Methods: Between October 2007 and July 2008, serum samples were collected from 40 clinically healthy guinea pigs of different sexes, ages, and breeds that were presented to our clinic for a general health check or for castration. Pregnant females were excluded from the study. Thyroxine concentration was measured using a chemiluminescence test (Immulite 2000 Canine Total T4). Results: Thyroxine concentrations ranged from 14.2 to 66.9 nmol/L (1.1–5.2 μg/dL) with a median value of 27.0 nmol/L (2.1 μg/dL). Females (n=16) had significantly (P=.039; Mann–Whitney U‐test) lower thyroxine values than castrated males (n=8), whereas no differences were found between females and intact males (n=16) or between intact and castrated males. No significant correlation was found between thyroxine concentration and age. Conclusion: This is the first report of serum thyroxine reference values for a well‐defined population of healthy pet guinea pigs as measured by a chemiluminescence assay. The results were higher than those previously reported for this species and emphasize the importance of using appropriate reference intervals for the diagnosis of hyperthyroidism.     

Crust formation on sandy soils in the Sahel II. Tillage and its effect on the water balance

The water balance for millet fields and for permanently crusted natural pastures is described, with special emphasis on the role of the crust in governing infiltration and runoff. Tillage destroys the crust and increases the surface storage for rainwater. The crust-breaking effect will last for only a few rainshowers, but the increase of surface storage is more permanent. The effect of a tillage system on the water balance of a millet crop is calculated.Tied ridges, giving a surface storage of 20–30 mm, could prevent runoff (which is about 50% under the conventional system) completely. It is expected that this would allow earlier sowing and thus prolong the vegetative growth by as much as 20 days, which might increase the average millet yield (500 kg ha^?1) by 40%.