Comparison of individual assignment methods and factors affecting assignment success in cattle breeds using microsatellites

Abstract

Comparisons of seven different individual assignment methods based on likelihood and distances were carried out with four different sets of data, which varied both in number of populations and genetic divergence. Based on 27 microsatellites genotyped in eight cattle breeds (Icelandic and seven Norwegian), 28 hybrid populations were simulated. Factors affecting individual assignment success, such as number and divergence of populations, sample size and number of loci, were assessed from actual and simulated data. The Bayesian, frequency and Nei-minimum methods performed more or less similarly. Individual assignment success depended mainly on population number and divergence (F_ST). Higher success was observed at high level of divergence among populations and at low number of source populations considered. With eight pure breeds and 27 loci considered the assignment success rate ranged from 55 to 70%. Generally, assignment success increased with increasing number of loci and/or sample size.     

Using value functions to elicit spatial preference information

Decision making in forest planning often involves situations, where the value of the stand is dependent on its location or the properties of the stands nearby. Often the most intuitive tool to describe spatial objectives and outcomes is a visual map. However, evaluating and comparing different maps may prove a considerable cognitive burden, especially over large areas and in long-term planning. In this study, we investigate the use of value functions for eliciting spatial preference information from maps. Our case study is part of a project investigating the possibilities of increasing broadleaf-tree-dominated habitats in a northern Swedish landscape. The experts involved in the project evaluated maps showing different fragmentation patterns. Different spatial indices were then calculated for the maps, and expert evaluations were used to sketch value functions describing the preferred fragmentation level. The approach was found to be a quick way of translating spatial preferences into numerical values and conceptualizing the relatively abstract concept of fragmentation in the landscape. Furthermore, the results show that the choice of a certain fragmentation index has a crucial effect on the value function.     

Anti-hyperglycemic Effect of the Aqueous Extract of Banana Infructescence Stalks in Streptozotocin-induced Diabetic Rats

Water extract of banana (Musa sapientum) infructescence stalks has been used in folk medicine in the treatment of diabetes mellitus. This work aims at verifying the claimed effect and elucidating its possible mode of action. The extract was given in replacement of drinking water to diabetic rats, and its mechanism of action was studied by investigating its involvement in glucose transport in Caco-2 monolayers, and in rat jejuna using an in situ perfusion technique. Its effect on the Na⁺/K⁺ ATPase was studied by measuring the amount of inorganic phosphate liberated. The extract reduced significantly blood glucose levels in diabetic rats and glucose transport across rat jejuna and Caco-2 monolayers, and induced a 50 % decrease in their Na⁺/K⁺ ATPase activity. The extract did not induce any further decrease in jejunal glucose uptake in the simultaneous presence of phloridzin and phloretin, respective inhibitors of SGLT1 and GLUT2 transporters nor did it induce a change in the protein expression of SGLT1 and GLUT2. It was concluded that the extract acts by reducing the Na⁺/K⁺ ATPase activity of enterocytes and consequently the sodium gradient required for sugar transport by SGLT1, which leads to down-regulation of GLUT2 and contributes to the observed anti-hyperglycemic effect.     

A climate for commerce: the political agronomy of conservation agriculture in Zambia

The promotion of conservation agriculture (CA) for smallholders in sub-Saharan Africa is subject to ongoing scholarly and public debate regarding the evidence-base and the agenda-setting power of involved stakeholders. We undertake a political analysis of CA in Zambia that combines a qualitative case study of a flagship CA initiative with a quantitative analysis of a nationally representative dataset on agricultural practices. This analysis moves from an investigation of the knowledge politics to a study of how the political agendas of the actors involved are shaping agrarian practices. From its initial focus on CA as soil conservation and sustainable agriculture, the framing of the initiative has evolved to accommodate shifting trends in the policy arena. In tandem with the increased focus on climate adaptation, we see an increased emphasis on private sector-led modernisation. The initiative has shifted its target group from the poorest smallholders to prospective commercial farmers, and has forged connections between its farmer-to-farmer extension network and private input suppliers and service providers. The link between CA and input intensification is reflected in national statistics as a significantly higher usage of herbicides, pesticides and mineral fertilizer on fields under CA tillage compared to other fields. We argue that the environmental and participation agendas are used to buttress CA as an environmentally and socially sustainable agricultural development strategy, while the prevailing practice is the result of a common vision for a private sector-led agricultural development shared between the implementing organisation, the donor and international organisations promoting a new green revolution in Africa.     

Effects of temporal aggregation in integrated strategic/tactical and strategic forest planning

Integrated approaches to forest planning lead to large models and there is a subsequent need for a reduction of the number of constraints and variables. One way of achieving this is to aggregate data, either spatially or temporally. In this paper an integrated forest planning mixed integer model that takes into account both long-term strategic and shorter-term tactical forest management decisions is utilised. The study analyses the consequences of temporal aggregation in the strategic part of the integrated model, whereas the tactical part is modelled by a fixed set of years divided into seasons. For reference, analyses are also made using a pure strategic linear programming model. Cases using both equal and variable strategic period lengths are presented, and two case study areas are used. Results indicate that integrated plans, as well as strategic plans, are not particularly affected by the number of equal length strategic periods when more than five periods, i.e. less than 20 year period length, are used. When modelling strategic and integrated problems using variable-length periods, care should be taken to ensure that harvest operations late in the planning horizon get enough timing options to be adequately described.     

Environmental control of growth and flowering of Rubus idaeus L. cv. Glen Ample

Environmental control of the annual growth cycle of ‘Glen Ample’ raspberry has been studied in order to facilitate crop manipulation for out-of-season production. Plants propagated from root buds were raised in long days (LD) at 21 °C and then exposed to different temperature and daylength conditions at varying ages. Shoot growth was monitored by weekly measurements and floral initiation by regular sampling and examination of axillary bud #5. Under natural summer daylight conditions at 60°N shoot growth was nearly doubled at 21 °C compared with 15 °C, while at 9 °C one half of the plants ceased growing and formed flower buds at midsummer. Developing shoots have a juvenile phase and could not be induced to flower before the 15-leaf stage. No significant reduction in induction requirements was found in larger plants. Plants exposed to natural light conditions from 10th August, had an immediate growth suppression at 9 and 12 °C with complete cessation after 4 weeks (by September 7). This coincided with the first appearance of floral primordia. At 15 °C both growth cessation and floral initiation occurred 2 weeks later (by September 21), while at 18 °C continuous growth with no floral initiation was maintained until early November when the photoperiod had fallen below 9 h. The critical photoperiod for growth cessation and floral initiation at 15 °C was 15 h. Plants exposed to 10-h photoperiods at 9 °C for 2–4 weeks had a transient growth suppression followed by resumed growth under subsequent high temperature and LD conditions, while exposure for 5 or 6 weeks resulted in complete growth cessation and dormancy induction. The critical induction period for floral initiation was 3 weeks although no transitional changes were visible in the bud before week 4. When exposed to inductive conditions for marginal periods of 3 or 4 weeks, an increasing proportion of the plants (20% and 67%, respectively), behaved as primocane flowering cultivars with recurrent growth and terminal flowering. It is concluded that growth cessation and floral initiation in raspberry are jointly controlled by low temperature and short day conditions and coincide in time as parallel outputs from the same internal induction mechanism.     

Prospects for the future of pink salmon in three oceans: From the native Pacific to the novel Arctic and Atlantic

While populations of other migratory salmonids suffer in the Anthropocene, pink salmon (Oncorhynchus gorbusca Salmonidae) are thriving, and their distribution is expanding both within their natural range and in the Atlantic and Arctic following introduction of the species to the White Sea in the 1950s. Pink salmon are now rapidly spreading in Europe and even across the ocean to North America. Large numbers of pink salmon breed in Norwegian rivers and small numbers of individuals have been captured throughout the North Atlantic since 2017. Although little is known about the biology and ecology of the pink salmon in its novel distribution, the impacts of the species' introduction are potentially highly significant for native species and watershed productivity. Contrasts between pink salmon in the native and extended ranges will be key to navigating management strategies for Atlantic nations where the pink salmon is entrenching itself among the fish fauna, posing potential threats to native fish communities. One key conclusion of this paper is that the species' heritable traits are rapidly selected and drive local adaptation and evolution. Within the Atlantic region, this may facilitate further establishment and spread. The invasion of pink salmon in the Atlantic basin is ultimately a massive ecological experiment and one of the first examples of a major faunal change in the North Atlantic Ocean that is already undergoing rapid changes due to other anthropogenic stressors. New research is urgently needed to understand the role and potential future impacts of pink salmon in Atlantic ecosystems.     

Effects of dietary marine microalgae,Tetraselmis suecica,on production,gene expression,protein markers and bacterial count of Pacific white shrimp Litopenaeus vannamei

The marine flagellated Chlorophyta Tetraselmis suecica is among the most important live food species in marine aquaculture. In the present study, the effects of dietary supplementation of dried marine microalgae, Tetraselmis suecica, on growth performance; feed utilization; chemical composition; gene expression of superoxide dismutase (SOD), glutathione peroxidase (GPx) and insulin‐like growth factor 2 (IGF‐II) gene of Pacific white shrimp, Litopenaeus vannamei; muscle protein polymorphism; and microbial count were assessed and evaluated. Three hundred and sixty L. vannamei (postlarvae) Pls (0.124 ± 0.002 g) were randomly stocked into 40‐L glass aquaria (30 shrimp/aquarium) and fed three times daily four tested diets: a basal diet (control), diet incorporated with 2.5 g kg^?1 dried T. suecica (T1), 5 g kg^?1 dried T. suecica (T2) and 7.5 g kg^?1 dried T. suecica (T3) in triplicates, for 90 days. At the end of the trial, the survival rate (SR) of L. vannamei fed diets supplemented with different levels of T. suecica was significantly (p < .05) higher than the control diet. The highest weight gain and specific growth rate and the best feed conversion ratio were recorded on L. vannamei fed a diet supplemented with a 7.5 g/kg dried T. suecica. The highest protein, lipid and ash contents were obtained in L. vannamei fed the diet containing 7.5 g/kg T. suecica, when compared with the remaining tested diets. The gene expression of antioxidant genes SOD and GPx was the lowest in the T3 group in comparison with the control group. Meanwhile, expression level of IGF‐II was higher in the T2 group. The total heterotrophic bacterial count was significantly (p < .05) increased with the cumulative T. suecica level, while no significant (p > .05) differences were found in the total Vibrio count among treatments. Overall, the present results have shown that the diet supplemented with the highest inclusion level of dried T. suecica resulted in improved growth and nutrient utilization.     

Recent ice-sheet growth in the interior of Greenland

A continuous data set of Greenland Ice Sheet altimeter height from European Remote Sensing satellites (ERS-1 and ERS-2), 1992 to 2003, has been analyzed. An increase of 6.4 +/- 0.2 centimeters per year (cm/year) is found in the vast interior areas above 1500 meters, in contrast to previous reports of high-elevation balance. Below 1500 meters, the elevation-change rate is -2.0 +/- 0.9 cm/year, in qualitative agreement with reported thinning in the ice-sheet margins. Averaged over the study area, the increase is 5.4 +/- 0.2 cm/year, or approximately 60 cm over 11 years, or approximately 54 cm when corrected for isostatic uplift. Winter elevation changes are shown to be linked to the North Atlantic Oscillation.