21603 research outputs found
Sort by
Development of a scale to assess pigs' immediate behavioural reaction when encountering novel odours
Get PDFIt is currently not possible to predict how pigs will perceive novel odours, or whether certain odours might evoke avoidant or exploratory behavioural reactions. This study aimed to develop a reaction scale to assess the immediate behavioural reactions of pigs when encountering an odour for the first time. A secondary aim was to compare if reactions to different odours varied consistently among pigs, which could indicate that the reaction scale could be used to assign odour valence. The experiment included 184 growing-finishing pigs tested in 92 pairs of opposite-sex littermates. All pig pairs were presented with three out of a total of twelve different odours, in a balanced order. The odour samples consisted of six drops of essential oils (undiluted) on filter paper in a plastic container. Each of the three odours was presented along with an odourless control (distilled water). The odour and control samples were available to the pigs during 1-minute trials. The pigs' behavioural reactions were recorded six seconds after each pig had first approached the sample. The reaction was scored on a scale from 1 to 6, where 1 was exploratory behaviour (e.g., sniffing) and 6 was active avoidance behaviour (e.g., leaving, head shaking). An ordinal mixed-effects model was fitted to the data and showed no effect of sex, age, or odour triad on reaction scores, but an effect of treatment with odour eliciting significantly more exploratory behaviour (lower reaction score) than control (P < 0.001). Pigs expressed large individual differences in reactions to 10 of the 12 odours, but a consistent pattern of significantly more exploratory reactions to vanilla and blood orange (both odours: P < 0.05), which could suggest that pigs may perceive these odours as particularly pleasant. Reaction scores were significantly lower (i.e., pigs performing more explorative behaviour) for the first odour tested compared with subsequent odours (P <= 0.04) irrespective of the specific odour. The 6-point scale effectively described explorative and avoidance behaviours that may reflect the valence of the pigs' reactions. To our knowledge, this is the first scale specifically developed to assess pigs' immediate behavioural reactions to novel olfactory stimuli in a commercial production environment. The development of the reaction scale and the findings provide useful guidance for future research on odour perception. The observed decrease in interest over time should be taken into account when repeated testing is used
Parasite-host contact in the Arctic: dispersal behaviour of infective nematode larvae from Svalbard reindeer faeces
Get PDFGastro-intestinal parasitic nematodes are typical pathogens of mammalian herbivores. A key moment of infection by passively ingested nematodes is the contact between infective larvae and the grazing host. Yet, knowledge on dispersal dynamics of larvae infecting wild herbivores in natural environments is limited. We studied the mode and range of lateral larval movement. As study species, we used infective larvae of Ostertagia gruehneri-a parasitic nematode that can negatively affect its host, Svalbard reindeer (Rangifer tarandus platyrhynchus). In the laboratory, reindeer faecal pats containing larvae were introduced onto soil placed either horizontally or on a slope (10 degrees), mimicking the micro-topography of High Arctic tundra. After four weeks, 939 live nematodes were recorded, of which 23% were in the soil, mostly underneath the faecal pat (20%). The remaining 3% that dispersed away from the pat did so in both sloped and flat soil. We conclude that the larvae were able to actively move from faeces to soil and that subsequent dispersal was limited and not assisted by gravity (slope). These insights reveal potential infection hotspots, providing a glimpse in the complex interplay between parasite and host
Artificial intelligence survival models for identifying relevant risk factors for incident diabetes in Azar cohort population
Get PDFBackground: This study aimed to identify some risk factors associated with time to diabetes type II events using artificial intelligence (AI) survival models (SM) in a population cohort from East Azerbaijan, Iran. Methods: Data from Azar-Cohort spanning from 2014 to 2020 was analyzed using the random forest (RF) variable selection method along with Cox regression to identify the most relevant risk factors associated with diabetes. We then developed prediction models using RF survival analysis. Lasso-variable selection and RF variable selection were used to select the most important variables. The concordance index (C-index) was used to evaluate the concordance of the prediction models. Results: Our LASSO-Cox regression identified six factors to be significantly associated with body mass index (BMI), use of sleep medication, and hypertension stage 1 and stage 2. The model included all variables with a C-index of 76.3%. In contrast, the RF analysis identified 21 important variables predicting a higher probability of having diabetes. Of those, WC, MCHC, triglyceride, and age were the most important predictors of diabetes. The RF model converged after 500 trees with an out-of-bag (OOB) of 0.28 and a C-index of 79.5%. Conclusion: RF machine learning algorithms and LASSO-Cox regression analyses consistently identified WC, hypertension, and MCHC as the main risk factors for developing diabetes. The RF approach demonstrated slightly better accuracy in predicting the likelihood of diabetes at different time points
Detection of Non-Native Pink Salmon (Oncorhynchus gorbuscha) in Swedish Rivers Using eDNA
Get PDFBiological invasions are increasing on a worldwide scale and can have severe ecological and economic consequences. Pink salmon (Oncorhynchus gorbuscha) have a native range in the Pacific Ocean but have been introduced and are now spreading in the Arctic and North Atlantic Oceans, including Sweden. A comprehensive eDNA sampling scheme was conducted in 27 river systems in south-western Sweden in 2023, with the aim to detect adult spawning pink salmon. We applied qPCR and dPCR analysis on aquatic eDNA samples. Results indicated the presence of pink salmon at 24 sites across 11 river systems. Pink salmon were not detected in any of the sampled rivers that drain into the Baltic Sea. However, pink salmon were present in a river only 35 km from the entrance to the Baltic Sea, which means there is a high risk pink salmon will spread into the Baltic Sea in the coming years. Catch reporting is generally low and camera fish counters are few across these systems; therefore, the strength of incorporating eDNA methods is beneficial for the development of pink salmon monitoring programs and aquatic invasive species management
Evidence-based urban greening: a missing piece in biodiversity conservation
Get PDFWith calls for increased greenery in cities to safeguard biodiversity and its associated benefits to humans, urban vegetation must be managed carefully and efficiently. It is time to change paths from current spurious attempts to manufacture resilience and instead usher in evidence-based urban greening to secure ecosystems for the future
Markens kolinlagring efter brand och avverkning
Get PDFKolinlagring i mark spelar en nyckelroll för att minska klimateffekter av människans koldioxidutsläpp. Boreal skogsmark innehåller stora mängder kol, men störningar som skogsbränder och kalhuggning leder till förlust av kol från marken.Här sammanfattas de biologiska mekanismer som påverkar återuppbyggnaden av kolförrådet i marken efter omfattande störningar.Kolinlagringen i marken är snabbast 15–80 år efter en störning och avtar sedan. Att kol binds snabbare i yngre skogar beror på hög växtproduktion och symbiotiskt mykorrhizamycel som hämmar nedbrytarsvampar.Vi behöver öka vår förståelse för ekosystemets kolbalans om vi vill skapa bra modeller av kolets kretslopp och ge bättre råd till beslutsfattare om hur markanvändningen påverkar kolbalansen i skog och mark
Extenuating lead toxicity in Chinese cabbage using organic acids: Comparative efficacy of acetic, citric, and tartaric acids
Get PDFLead (Pb) toxicity in the environment and plants has emerged as a significant global concern, primarily due to its entry into the human body through the food chain. Several physicochemical and biological techniques are being explored for Pb removal/immobilization. This study explored the efficacy of organic acids—citric acid (CA), acetic acid (AA), and tartaric acid (TA) in mitigating Pb toxicity in plants parts. The treatments included a control (CK, no acid treatment), citric acid (CA) at 0.25 mM (CA0.25) and 0.5 mM (CA0.5), tartaric acid (TA) at 100 mM (TA100) and 200 mM (TA200), and acetic acid (AA) at 100 mM (AA100) and 200 mM (AA200), each replicated in triplicate. Chinese cabbage (Brassica rapa) was used as the test crop. Our results revealed significant reductions in Pb concentrations in both plant parts (roots and leaves) as well as in soil following the addition of organic acid. Among the three acid treatments at different concentrations, tartaric acid (TA200) at 200 mM delivered the best results in reducing Pb accumulation in soil-plant system. It notably increased catalase activity (144 μmol g⁻¹), ascorbic acid (12,344 mg L⁻¹), superoxide dismutase (178 U mg⁻¹ protein), and glutathione (98.0 μg g⁻¹ FW), compared to citric and acetic acids treatments. Further, Pearson's correlation showed a strong negative relationship between Pb content and antioxidant activities, such as catalase, glutathione, and peroxidase (r > 0.90). This study revealed that the application of tartaric acid (TA), particularly at 200 mM through both exogenous and soil treatments, could be an effective strategy to minimize Pb accumulation in polluted areas
The rapid expansion of offshore wind farms challenges the reliability of ICES-coordinated fish surveys-insights from the Baltic Sea
Get PDFFish stock assessment and sustainable management requires that the whole distribution area of the managed fish stocks is representatively sampled. Along with an increasing demand for renewable energy in Europe, a growing number of areas are allocated for current and future offshore wind farms (OWF). Besides various unknown environmental effects, impacts on different stakeholder activities, such as fisheries, are considered during the implementation process. Scientific interests and tasks are, however, often marginalized. The current ban of commercial fisheries and fisheries monitoring in OWFs, in combination with an increase of OWF areas and habitat alteration within OWFs, might therefore bias the time series of scientific surveys and, thus, fisheries stock assessments. The expected increase in the overlap between OWFs and scientific fish surveys coordinated by the International Council for the Exploration of the Sea (ICES) in the Baltic Sea could result in, depending on the survey, up to 6.6-11.5% of the stations and transects being unavailable for sampling. We discuss the potential consequences for survey time series and stock assessments. Further, we aim to stimulate the discussion about the future of current standard surveys in the context of rapid expansions of OWFs, including the need for adaptations in survey design
Drought acclimation of beech seedlings depends largely on their rooting patterns and less on the fungal communities in soils
Get PDFAims The composition of soil fungal communities is known to impact tree performance. However, fungal communities differ among soils with different precipitation histories and may change during drought. This study aimed to determine the influence of soil origin and associated climate adaptation of fungal communities on European beech seedlings' drought responses. Methods Seedlings were established from the same seed source and grown in three soils with different precipitation histories but similar water retention properties. One year after establishment, half of the seedlings were exposed to a two-month drought with predawn leaf water potentials of about -1.5 MPa, the other half remained well-watered (control). Before and during the drought, soil and root fungal community composition, root architecture, seedling growth, carbon allocation and leaf physiology were determined. Results The drought effect on the fungal community composition was the lowest in dry region soils, suggesting a natural adaptation of the fungal communities to dry environments. Nevertheless, contrary to our expectations, the seedlings grown in dry region soils with respective adapted fungal communities were most affected by drought. This was evidenced by a lower predawn water potential, probably due to shorter root systems with higher root branching compared to those grown in moist region soils where a greater taproot length was observed. Conclusion Beech seedlings drought responses depend largely on their different rooting patterns and less on the soil fungal communities that are adapted to long-term precipitation conditions. Yet, microbial effects cannot be excluded. Future research should focus more on the role of specific microbial species on plant root growth and drought responses
Interactions of nitrogen and phosphorus in plant nutrition - Analysis of a 60-years old field experiment
Get PDFBackground and aimsThe aims are to determine to which extent different plant species increase nitrogen (N) acquisition in response to phosphorus (P) addition and P acquisition in response to N addition as well as to analyze resulting nutrient limitations.MethodsThe field experiment is replicated at ten sites in Sweden and comprises three fertilization regimes (low, medium, and high) each consisting of a control and a N, P, and NP treatment. Yields as well as N and P contents of the yields of four species (winter wheat, spring barley, oat, and sugar beet) were analyzed over 60 years.ResultsThe relative increase in yield P in response to N fertilization was larger than the relative increase in yield N in response to P fertilization for three species. Synergistic NP co-limitation was observed for all species at some sites. The synergistic growth effect in response to NP addition occurred at more sites at high than at low fertilization. At one nutrient-poor site, all species in all fertilization regimes were (synergistically) NP co-limited. Sugar beet was (synergistically) NP co-limited at all sites in all fertilization regimes.ConclusionSpecies differed in nutrient acquisition, but most species used added N more effectively to acquire P than they used added P to acquire N. Synergistic NP co-limitation was observed for all plant species at some sites, and it increased with fertilization rate, which is likely due to the limits to which plants can use N to acquire P and P to acquire N