168 research outputs found
Possibilities and limitations of vegetative propagation in breeding and mass propagation of Norway spruce
The use of vegetative mass propagation in practical forestry with Norway spruce (Picea abies (L.) Karst.) is limited at present, although its potential to deliver high genetic gains is obvious. The objective of this thesis was to study possibilities and limitations of vegetative propagation when applied in different parts of a breeding/mass propagation system for Norway spruce. Two vegetative propagation methods were studied: somatic embryogenesis and cutting propagation. Somatic embryogenesis was accompanied by losses of genotypes during the propagation process. The embryogenic response at proliferation and maturation was under family control, while germination was obtained for all families. Parental effects on proliferation and maturation were found for male parents but not for female. However, no correlations between embryogenic characters and breeding goal traits could be detected on parental level. Shortening of treatment with abscisic acid (ABA) during somatic embryo development gave pronounced positive effects on height growth of regenerated plants. An improved protocol, including five weeks ABA treatment and root development in liquid medium significantly improved performance of the resulting plants. The number of plants with lateral roots at the time of ex vitro transfer increased substantially with this protocol. Lateral roots at ex vitro transfer were shown to be a marker for good height growth and clonal uniformity during the next two years. Selection for height of cutting propagated clones in the nursery resulted in low responses in height after six years in field. The likely reason for this was low correlations between nursery traits and field traits. Genotype x environment interactions in the studied clonal test series varied from close to zero to more than 50% of the clone component. A tendency towards increased interaction components with age was obtained in one of the series. In situations with large genotype x environment interactions, clonal stability over sites should be included in the selection criteria
The changing roles of archaeology in Swedish Museums
Abstract: Please refer to full text to view abstrac
No future in archaeological heritage management?
Although the future is mentioned frequently in overarching aims and visions, and it is a major drive in the daily work of archaeological heritage managers and indeed heritage professionals more generally, it remains unclear precisely how an overall commitment to the future can best inform specific heritage practices. It seems that most archaeologists and other heritage professionals cannot easily express how they conceive of the future they work for, and how their work will impact on that future. The future tends to remain implicit in daily practice which operates in a continuing, rolling present. The authors argue that this needs to change because present-day heritage management may be much less beneficial for the future than we commonly expect
Animal Welfare Implications of Digital Tools for Monitoring and Management of Cattle and Sheep on Pasture
Simple SummaryMonitoring the welfare of cattle and sheep in large pastures can be time-consuming, especially if the animals are scattered over large areas in semi-natural pastures. There are several technologies for monitoring animals with wearable or remote equipment for recording physiological or behavioural parameters and trigger alarms when the acquired information deviates from the normal. Automatic equipment allows continuous monitoring and may give more information than manual monitoring. Ear tags with electronic identification can detect visits to specific points. Collars with positioning (GPS) units can assess the animals' movements and habitat selection and, to some extent, their health and welfare. Digitally determined virtual fences, instead of the traditional physical ones, have the potential to keep livestock within a predefined area using audio signals in combination with weak electric shocks, although some individuals may have difficulties in responding as intended, potentially resulting in reduced animal welfare. Remote technology such as drones equipped with cameras can be used to count animals, determine their position and study their behaviour. Drones can also herd and move animals. However, the knowledge of the potential effects on animal welfare of digital technology for monitoring and managing grazing livestock is limited, especially regarding drones and virtual fences.The opportunities for natural animal behaviours in pastures imply animal welfare benefits. Nevertheless, monitoring the animals can be challenging. The use of sensors, cameras, positioning equipment and unmanned aerial vehicles in large pastures has the potential to improve animal welfare surveillance. Directly or indirectly, sensors measure environmental factors together with the behaviour and physiological state of the animal, and deviations can trigger alarms for, e.g., disease, heat stress and imminent calving. Electronic positioning includes Radio Frequency Identification (RFID) for the recording of animals at fixed points. Positioning units (GPS) mounted on collars can determine animal movements over large areas, determine their habitat and, somewhat, health and welfare. In combination with other sensors, such units can give information that helps to evaluate the welfare of free-ranging animals. Drones equipped with cameras can also locate and count the animals, as well as herd them. Digitally defined virtual fences can keep animals within a predefined area without the use of physical barriers, relying on acoustic signals and weak electric shocks. Due to individual variations in learning ability, some individuals may be exposed to numerous electric shocks, which might compromise their welfare. More research and development are required, especially regarding the use of drones and virtual fences
Practical testing of Scots pine cutting propagation - a joint Metla-Skogforsk-Silava project
Layout: Eija MatikainenTesting of candidates as clones would greatly benefit breeding of Scots pine (Pinus sylvestris L.),but has not been applied because vegetative propagation is difficult. With a common interest in Scotspine breeding, forest research institutions from Sweden, Finland and Latvia (Skogforsk, Metla and Silava, respectively) joined in a collaborative project to develop pine cutting propagation for breedingpurposes. The main objective of this effort was to find protocols for sufficient shoot production and at the same time maintain a high rooting response. Secondly, the aim was to increase the knowledge onthe influence of different rooting agents, watering regimes and substrates on the rooting of cuttings.Both local and shared materials were used in studies of five propagation methods performed in all participating countries. Separate experiments were performed with rooting environment factors.According to the results, the average production of cuttings with propagation models including two harvests in consecutive years on the same donor plant can be predicted to be 10-15 cuttings/donor plant,with a substantial variation among families and donor plants. Even though rooting responses above 50% can be achieved, this could not be repeated for a large number of propagations. The generally lowand erratic rooting responses leads to the conclusion that the project was unsuccessful in developing improved and reliable protocols for Scots pine cutting propagation. However, a propagation model enabling two harvests on a 1-year-old plant within the same year is a promising option but needs further studies
Novel Avenues for Plant Protection: Plant Propagation by Somatic Embryogenesis Enhances Resistance to Insect Feeding
Somatic embryogenesis (SE), a clonal propagation method utilizing somatic cells, occurs under conditions that activate plant stress adaptation mechanisms such as production of protective secondary metabolites. Surprisingly, possible differences in susceptibility to insect pests between SE-generated and conventionally cultivated plants have not been previously explored. Here, we recorded frequencies and levels of bark-feeding damage by pine weevils (Hylobius abietis) in two large field trials, consisting of emblings (SE-propagated plants) and seedlings from 50 half-sib Norway spruce (Picea abies) families. We found that emblings were less frequently attacked by pine weevils, and when attacked, they were damaged to a lesser extent than seedlings. Moreover, we detected significant additive genetic variation in damage levels received by plants, indicating a heritable component to differences in resistance to insect herbivory among half-sib families. We present first-time evidence that emblings can be more resistant than seedlings to herbivorous insect damage, thus, SE appears to confer a previously unknown plant protection advantage. This finding indicates novel avenues to explore mechanisms underlying plant resistance and new approaches to develop non-toxic measures against insect pests
The Still Bay points of Apollo 11 Rock Shelter, Namibia : an inter-regional perspective
Abstract: Dating to roughly 80,000 to 70,000 years ago, components of the Still Bay technocomplex of southern Africa and their potential behavioural implications have been widely discussed. Stone points with invasive retouch, as defined over 90 years ago by Goodwin and van Riet Lowe, serve as markers for Still Bay assemblages, yet many Still Bay sites remain undated and comprehensive, comparable sets of data for their point assemblages remain unpublished. Much of the Middle Stone Age at the site of Apollo 11 in Namibia was undated until 2010, when a potential Still Bay component was announced. Although a Still Bay assemblage at Apollo 11 would represent the most northwesterly and inland expression of this technocomplex, its points have never been fully analysed. This paper presents their morphometric data and an interpretation of point-production strategies. These results are then compared with data obtained for two South African sites: Hollow Rock Shelter in the Western Cape and Umhlatuzana in KwaZulu-Natal. This comparison demonstrates that whereas there are no statistically significant differences in the morphometric data sets between the three sites, there are both similarities and differences in point-production strategies, cross-section shapes and the use of raw materials for knapping. It is suggested that these similarities and variations represent aspects of how knowledge-transfer systems and knapping conventions were followed on both intra-regional and inter-regional scales
Isolation and characterization of a small antiretroviral molecule affecting HIV-1 capsid morphology
Background Formation of an HIV-1 particle with a conical core structure is a prerequisite for the subsequent infectivity of the virus particle. We have previously described that glycineamide (G-NH2) when added to the culture medium of infected cells induces non-infectious HIV-1 particles with aberrant core structures. Results Here we demonstrate that it is not G-NH2 itself but a metabolite thereof that affects HIV-1 infectivity and capsid assembly. The conversion of G-NH2 to its antiviral metabolite is catalyzed by an enzyme present in bovine and porcine but surprisingly not in human serum. Structure determination by NMR suggested that the active G-NH2 metabolite was α-hydroxyglycineamide (α-HGA). Chemically synthesized α-HGA inhibited HIV-1 replication to the same degree as G-NH2, unlike a number of other synthesized analogues of G-NH2 which had no effect on HIV-1 replication. Comparisons by capillary electrophoresis and HPLC of the metabolite with the chemically synthesized α-HGA further confirmed that the antiviral GNH2-metabolite indeed was α-HGA. Conclusions α-HGA has an unusually simple structure and a novel mechanism of antiviral action. Thus, α-HGA could be a lead for new antiviral substances belonging to a new class of anti-HIV drugs, i.e. capsid assembly inhibitors
Phase tailoring of tantalum thin films deposited in deep oscillation magnetron sputtering mode
The effect of energetic ion bombardment on the properties of tantalum thin films was investigated. To achieve such energetic ion bombardment during the process the Ta thin films were deposited by deep oscillation magnetron sputtering (DOMS), an ionized physical vapor deposition technique related to high power impulse magnetron sputtering. The peak power was between 49 and 130 kW and the substrate was silicon at room temperature and ground potential. The directionality and the energy of the depositing species was controlled by changing the ionization fraction of the Ta species arriving at the substrate at different peak powers. In this work, the surface morphology (AFM), microstructure (SEM), structure (XRD) and hardness and Young's modulus (nanoindentation) of the films were characterized. The ion energy distributions (IEDs) were measured using an electrostatic quadrupole ion energy and mass spectrometer (HIDEN EQP 300). The IEDs showed that the DOMS process applies a very energetic (up to 120 eV) ion bombardment on the growing tantalum films. Therefore, with such conditions it was possible to deposit pure α-Ta (of 2 μm of thickness) without the use of additional equipment, i.e., without substrate bias or substrate heating. Conditions are therefore significantly different than in previous works, offering a much simpler and cheaper solution to up-scale for industrial operation
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