Tree ring anatomy indices of Pinus tabuliformis revealed the shifted dominant climate factor influencing potential hydraulic function in western Qinling Mountains

Trees can adjust xylem anatomical structure related with potential hydraulic functions to cope with climate variability. We therefore need a better understanding of how climate variability constrains wood anatomy and tree radial growth. Pinus tabuliformis dominates natural forests and plantations over the western Qinling Mountains, which is one of the ecologically vulnerable areas in China. Here, we investigated the response of P. tabuliformis tree-ring anatomical structure to climate variability by applying wood anatomy analysis, and evaluated the influences of anatomical traits on potential hydraulic functions and the climate significance of intra-annual density fluctuations (IADFs). We found that with the increasing temperature from spring to summer, the negative effect of temperature on the formation and enlargement of earlywood and transition-wood tracheids was gradually enhanced. However, spring precipitation not only had a direct and positive influence on the formation of earlywood, but also had a delaying impact on the transition-wood cell enlargement. Besides, the smaller earlywood tracheid size of P. tabuliformis could be a substantially characteristic reflecting spring drought. The contribution of lumen diameter on conduit wall reinforcement was dominated in earlywood, while the contribution of cell wall thickness was greater than that of lumen diameter in latewood. The different contributions of anatomical traits on conduit wall reinforcement would further affect the response of potential hydraulic function to climate. IADFs of P. tabuliformis could be a potential indicator to reflect the abnormal summer precipitation events in the western Qinling Mountains. IADFs with strong and weak intensity indicated years with high and low rates of change in mid-summer precipitation, respectively. Future warmer and drier climate in the western Qinling Mountains will likely result in the production of smaller tracheids to ensure hydraulic safety, which means the stronger drought resistant of P. tabuliformis in the future. In this study, we linked the xylem anatomy and potential hydraulics functions with intra-seasonal climate variability in the context of climate warming and drying, and proposed some xylem anatomical indices reflecting potential drought events.     

Effect of tower base painting on willow ptarmigan collision rates with wind turbines

1. Birds colliding with turbine rotor blades is a well‐known negative consequence of wind‐power plants. However, there has been far less attention to the risk of birds colliding with the turbine towers, and how to mitigate this risk.
2. Based on data from the Smøla wind‐power plant in Central Norway, it seems highly likely that willow ptarmigan (the only gallinaceous species found on the island) is prone to collide with turbine towers. By employing a BACI‐approach, we tested if painting the lower parts of turbine towers black would reduce the collision risk.
3. Overall, there was a 48% reduction in the number of recorded ptarmigan carcasses per search at painted turbines relative to neighboring control (unpainted) ones, with significant variation both within and between years.
4. Using contrast painting to the turbine towers resulted in significantly reduced number of ptarmigan carcasses found, emphasizing the effectiveness of such a relatively simple mitigation measure.

     

Pharmacological and Physicochemical Properties of Pre-Versus Postsynaptic 5-Hydroxytryptamine1A Receptor Binding Sites in the Rat Brain: A Quantitative Autoradiographic Study

Numerous data suggested that the pharmacological and biochemical properties of 5-hydroxytryptamine1A (5-HT1A) receptors exhibit some regional differences in the CNS, notably within the raphe nuclei compared with various forebrain areas (such as the hippocampus). This possibility has been further investigated in the dorsal raphe nucleus and two areas within the hippocampus, the dentate gyrus and the CA1 area, using the quantitative autoradiographic technique. The potencies of 5'-guanylylimidodiphosphate to inhibit the specific binding of 125I-Bolton-Hunter-8-methoxy-2-(N-propyl-N-propylamino)tetralin (125I-BH-8-MeO-N-PAT) to 5-HT1A sites and of N-ethylmaleimide to block these sites irreversibly were identical in the dorsal raphe nucleus and the hippocampal areas in rat brain sections. In contrast, slight but significant differences were noted in the pH dependence and pharmacological properties of 5-HT1A sites labeled by 125I-BH-8-MeO-N-PAT in these three regions. Similarly, heat denaturation experiments and tissue exposure to either phospholipase A2 or the alkylating agent 8-methoxy-2-(N-2'-chloropropyl,N-propyl)aminotetraline revealed regional differences in the properties of 5-HT1A sites. However, in most cases, the observed variations were of greater amplitude between the CA1 area and the dentate gyrus, where 5-HT1A sites are located postsynaptically, than between any one of these areas and the dorsal raphe nucleus where they act as (presynaptic) somatodendritic autoreceptors. These data further support that subtypes of 5-HT1A receptors probably exist in the rat brain, but this heterogeneity seems unrelated to the pre- or post-synaptic location of these receptors.     

Detection of cyanobacterial sxt genes and paralytic shellfish toxins in freshwater lakes and brackish waters on Åland Islands,Finland

Harmful cyanobacteria are a globally growing concern. They produce a large variety of toxic compounds, including saxitoxin and its many structural variants, a group of potent neurotoxins collectively called paralytic shellfish toxins or PST. Nucleic acid based detection methods, such as qPCR, have been proposed as potential screening and monitoring tools for toxic cyanobacteria, but it is not clear how well the presence and quantity of saxitoxin biosynthesis (sxt) genes can be used to predict the production of PST in the environment. In this study, the prevalence of three sxt genes and their co-occurrence with paralytic shellfish toxins in the environment was investigated. The sxtA, sxtG and sxtB genes were present on average in 31% of the samples collected from lakes and brackish coastal waters on Åland Islands, Finland, during the three-year monitoring period. PST detection frequency varied from 13% to 59% from year to year, and concentrations were generally low. On average higher sxtB copy numbers were associated with PST detection, and although a positive correlation between gene copy numbers and toxin concentrations was observed (Spearman rank correlation, ρ = 0.53, P = 0.012), sxt gene presence or quantity didn’t reliably predict PST production. Sequencing of sxtA fragments and identification of main cyanobacteria indicated that the likely candidate responsible for PST production in the samples belonged to the genus Anabaena.     

Providing straw to allow exploratory behaviour in a pig experimental system does not modify putative indicators of positive welfare: peripheral oxytocin and serotonin

Numerous studies have shown that providing straw to pigs can reduce undesirable behaviours such as aggression, tail biting and stereotypy. The measurement of various neuromodulators can be helpful in assessing the development of positive behaviours and overall animal welfare. The oxytocin release is frequently linked to positive emotions and positive welfare. It has been suggested that oxytocin modulates the serotoninergic system. This study aims to investigate the potential effect of straw provision in pigs on peripheral levels of oxytocin and serotonin. In total, 18 mini-pigs were involved in an exploratory study conducted in two parallel groups, Enriched (n=10) and Control (n=8) groups. Pigs were divided by group and housed in pens of two individuals. Straw was provided continuously only in Enriched group and renewed each day for 2 weeks. Two blood samples were drawn from each animal 5 to 10 min before providing the straw, and 15 min after providing straw, during the 1^st week, to analyse peripheral changes in oxytocin and serotonin before and after straw provision, and determine the existence of a putative short-term effect. The same procedure was carried out for Control group, without straw provision. Long-term effects of straw provision were also examined using blood samples drawn at the same hour from each animal in the 2^nd and 3^rd weeks. During this time, animals had the permanent possibility to explore the straw in Enriched group but not in Control group. At the end of each week, one animal-keeper completed two visual analogue scales for each mini-pig regarding the difficulty/ease to work with and handle it and its trust in humans. Results showed peripheral oxytocin increases in both groups after 2 weeks (P=0.02). Results did not demonstrate any effect of providing straw to allow exploratory behaviour on peripheral serotonin. Other results were not significant. This preliminary study explored the relationship between peripheral oxytocin and serotonin and the presence of straw that allow pigs to perform exploratory behaviour, suggesting that there was no relationship between them. Some future studies may include crossing oxytocin and serotonin with other parameters, such as behavioural measures, to obtain more information about the true state of the animal and any possible relationship with pig welfare.     

Bayesian Quantile Regression for Longitudinal Studies with Nonignorable Missing Data

Summary .  We study quantile regression (QR) for longitudinal measurements with nonignorable intermittent missing data and dropout. Compared to conventional mean regression, quantile regression can characterize the entire conditional distribution of the outcome variable, and is more robust to outliers and misspecification of the error distribution. We account for the within-subject correlation by introducing a   ℓ₂   penalty in the usual QR check function to shrink the subject-specific intercepts and slopes toward the common population values. The informative missing data are assumed to be related to the longitudinal outcome process through the shared latent random effects. We assess the performance of the proposed method using simulation studies, and illustrate it with data from a pediatric AIDS clinical trial.     

Parametric and Nonparametric Analyses of Repeated Ordinal Categorical Data

We compare two models for the analysis of repeated ordinal categorical data: the classical parametric model for means of scores assigned to the categories of the response variable and a nonparametric model based on relative effects derived from the marginal distribution functions of the response. An example in the field of Dentistry is used to illustrate and to compare the models. We also consider a simulation study to evaluate the type‐I error rates and the power of tests under both models in a balanced design setup. The simulation results suggest that both approaches behave similarly for equally spaced scores but may perform differently otherwise. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Isolation of high molecular weight DNA from wholeEuglena cells

Summary A method for isolating high quality DNA from wholeEuglena cells is described. The procedure consists in: the weakening of the cell pellicle in glycerol avoiding the mechanical disruption of cells and shearing damage in DNA molecules; the decondensation ofEuglena compact chromatin directly inside the cells; the complete dissociation of cells and nucleoproteins in sarkosyl detergent; the optional digestion of proteins and RNA with DNase-free enzymes and the final purification of DNA by isopycnic banding in CsCl gradients. Degradation of DNA is prevented all along the extraction procedure by glycerol, antioxydants, EDTA and sarkosyl detergent. Using the enzymatic digestion step, DNA containing few single-stranded nicks is obtained with a yield approaching 100%. DNA with no single-stranded nick could be obtained with a 35% yield when the enzymatic digestion step was omitted. In both cases, the double-stranded DNA has an average molecular weight equal or greater than 6×10⁷. It is free of contaminants and could be easily digested with restriction enzymes. After digestion with Eco RI and size-fractionation in agarose gel this DNA has permitted specific hybridization of the rDNA sequences with a radioactive rRNA probe.Abbreviations Kbp kilobasepairs - Kb kilobases     

Diversity within and between populations of two sympatrically distributed Hordeum species in Jordan

Summary The diversity of two sympatrically distributed barley species (Hordeum vulgare L. and Hordeum spontaneum C. Koch.) has been assessed for 7 morphometric and 13 qualitative traits. Phenotypically, Hordeum vulgare was more stable than Hordeum spontaneum for all morphometric traits; this is a reflection of domestication and selection. The overall diversity indexes were 0.546±0.125 and 0.502±0.113 for Hordeum vulgare and Hordeum spontaneum, respectively (P=0.095). However, Hordeum spontaneum expressed a higher level of diversity for most qualitative traits. The observed similarity for a number of diversity indexes is probably due to gene flow between the two species.