Stand density and fertilization effects on aboveground allocation patterns and stem form of Pinus sylvestris in young stands     

Kristina Ahnlund Ulvcrona  Thomas Ulvcrona  Urban Nilsson  Tomas Lundmark 《Scandinavian Journal of Forest Research》2014,29(3):197-209

The increasing demand for forest biomass for energy generation could be partially met by growing denser stands and use of fertilizer. Before this is done at large scale, more knowledge of the effects of stand density and fertilization on aboveground allocation patterns and stem form is needed. Therefore, effects of pre-commercial thinning (PCT) to 3000 stems ha^?1, an unthinned dense control (C), and PCT combined with two levels of fertilization (100 kg ha^?1 of nitrogen applied either during the establishment of the field experiment (F1) or annually (F2)) were examined in 23- to 26-year-old Scots pine (Pinus sylvestris L.) stands six years after the establishment of the field experiment. In total, 114 sample trees were harvested using destructive biomass sampling. The growth allocation and stem form of trees with diameter at breast height (DBH; 1.3 m height) >5.0 cm were not affected by either the PCT or fertilization. Small trees (DBH < 5 cm) in denser, unthinned control plots had more slender stems (lower DBH/height ratios) and allocated less growth to branches and foliage than trees in PCT plots. Fertilization had little effect on the stem form and growth allocation of the smallest trees. Therefore, effects of stem density and fertilization on stem form and growth allocation to foliage were only found for small suppressed trees, and the treatments had very little influence on dominant and codominant trees.  相似文献   

Aluminium chemistry and acidification processes in a shallow podzol on the Swedish westcoast     

S. Ingvar Nilsson  Bo Bergkvist 《Water, air, and soil pollution》1983,20(3):311-329

Processes pertinent to soil acidification with special emphasis on the solution chemistry of A1, were studied in three adjacent small catchments on the Swedish westcoast, with mixed coniferous forest and shallow podzols (average soil depth 50 cm). Soil solution from different depths, groundwater and stream-water were sampled. Separation of organic and inorganic Al species was done with an ion exchange technique. The concentration of organic A1 species was linearly correlated with the concentration of dissolved organic C (r,², varied from 0.38 to 0.69 with p, < 0.001). In the A horizon 83 to 97 % of the dissolved A1 consisted of organic species. The average concentration of total A1 varied from 3.3 to 9.8 μmole 1^?1, in soil leachates collected below the A₀, horizon, and from 29.3 to 47.0 pmole 1^?1, in leachates collected below the A₂, horizon. The organic Al species decreased in importance with increasing soil depth. Leachates collected below the B horizon had average total A1 concentrations ranging from 95.3 to 115 pmole 1^?1, with a contribution of organic species varying between 8 and 20% of the total concentration. Activity calculations indicated an equilibrium with A1(OH)SO₄, (pK _S = 17.23) in the lower part of the B horizon, while groundwater together with some of the leachates from the upper B horizon showed a better fit with A1₁₄(OH)₁₀SO₄ (pK₁ = 117.51). Streamwater was obviously influenced by the soil organic matter in the outflow areas in terms of A1- organic matter complexes and protolysis of dissolved organic acids. There was a net outflow of Al and sulphate from the lower part of the B horizon compared to input in throughfall precipitation. The relative concentration increase varied from 64.4 to 78.0 (A1) and from 1.52 to 1.92 (sulphate). The relative increase due to evapotranspiration was estimated to be 1.4. The corresponding concentration factors for Mg and Ca were from 2.06 to 2.38, and from 0.81 to 1.07, respectively, indicating a very low Ca weathering. Data were compared with other studies, both recent and older ones. The possible influence from present-day levels of H⁺ and sulphurous compounds in the atmospheric deposition is evaluated.  相似文献   

Analysis of early lipid oxidation in smoked, comminuted pork or poultry sausages with spices     

Olsen E  Vogt G  Veberg A  Ekeberg D  Nilsson A 《Journal of agricultural and food chemistry》2005,53(19):7448-7457

Dynamic headspace/gas chromatography-mass spectrometry (GC-MS), front-face fluorescence spectroscopy, and a gas-sensor array technique (electronic nose) have previously detected lipid oxidation in pork back fat or mechanically recovered poultry meat earlier than or at the same time as a sensory panel. The present study was focused on measurement of early lipid oxidation in a more complicated product (freeze-stored, smoked sausages with spices). During the storage time, formation of components contributing to rancid odor and flavor (e.g., hexanal and 1-penten-3-ol) could be monitored with dynamic headspace/GC-MS. The GC-MS data also showed a decrease in 2-furancarboxaldehyde, which could indicate loss of Maillard type components often associated with acidic or meat odor and flavor. The fluorescence spectra were difficult to interpret, probably due to the simultaneous influence from increasing levels of lipid oxidation products and loss of fluorescent Maillard or spice components. The gas-sensor array responses were dominated by signals from, e.g., spice and smoke compounds.  相似文献   

Retention and Long Term Accumulation of EOCl from Pulp Mill Effluents in a Baltic Sea Recipient     

Nilsson  Per  Jansson  Mats  Brydsten  Lars 《Water, air, and soil pollution》2003,143(1-4):225-243

The total inventory and distribution of ExtractableOrganic Chlorine (EOCl) has been investigated in anestuary exposed to pulp mill effluents for over 50 yr.The estuarine turnover of suspended particulate matter(SPM) and associated pollutants was studied using a modeldescribing important processes for EOCl accumulation. Therecipient has a low retention of SPM due to dominatingstratified conditions in the water column. The totalinventory of EOCl in the sediment is therefore relativelylow as compared with the total discharge. It was foundthat the vertical distribution of EOCl has a closerelationship to the extent of chlorine use at the mill.Discharges of SPM from the pulp production process play amajor role in establishing the chronology of the sediment.A modernisation of the mill from 1986 to 1991 considerablyreduced the discharges of chlorinated substances. In the near future there will be an accumulation of EOCl in the estuary.  相似文献   

Analysis of the early stages of lipid oxidation in freeze-stored pork back fat and mechanically recovered poultry meat     

Olsen E  Vogt G  Ekeberg D  Sandbakk M  Pettersen J  Nilsson A 《Journal of agricultural and food chemistry》2005,53(2):338-348

An analytical method that can detect low levels of oxidation in food earlier than a sensory panel would be a valuable tool for food manufacturers as well as research institutes. Two model matrixes, pork back fat and mechanically recovered poultry meat (MRPM), were freeze-stored in air at -20 degrees C for 26 weeks. Peroxide value, thiobarbituric acid reactive substances, volatiles analyzed with dynamic headspace gas chromatography-mass spectrometry (GC-MS) and a gas-sensor array technique (electronic nose), chemiluminescence, and front-face fluorescence were evaluated against sensory analysis with regard to detection of early oxidation and correlation with sensory data. Fluorescence and GC-MS could detect oxidative changes in pork back fat earlier than the sensory panel and the electronic nose at the same time. The three methods were highly correlated with sensory attributes (r = 0.8-0.9). GC-MS gave the best results with regard to detection of small oxidative changes in MRPM.  相似文献   

A comparative study of neurologically-equivalent propofol anaesthetic combinations in the dog     

Antonello Bufalari  Lena E. Nilsson  Charles E. Short  Claudia Giannoni 《Veterinary anaesthesia and analgesia》1995,22(1):19-24

Propofol, administered as the sole anaesthetic agent, was evaluated when given alone and to dogs premed-icated with acepromazine or medetomidine. Both preanaesthetic agents reduced the dose of propofol required for induction of anaesthesia. Medetomidine significantly reduced the dose of propofol required for the maintenance of anaesthesia for a 30-minute period. An equivalent depth of anaesthesia was established in each protocol as judged by lack of response to mechanical noxious stimuli and total amplitude reduction of brain wave activity. Differences in physiological responses between propofol and acepromazine/propofol were not significant. The dogs in the medetomidine/propofol group had a significantly higher blood pressure and longer duration of anaesthesia and recovery. Oxygen saturation was maintained above 90% by the administration of supplemental oxygen. The study demonstrated the comparative responses to a biologically equivalent depth of anaesthesia, as confirmed by brain wave analysis, using three different techniques using propofol.  相似文献   

Epigenetics and transgenerational inheritance in domesticated farm animals     

Amanda Feeney  Eric Nilsson  Michael K Skinner 《畜牧与生物技术杂志(英文版)》2014,5(1)

Epigenetics provides a molecular mechanism of inheritance that is not solely dependent on DNA sequence and that can account for non-Mendelian inheritance patterns. Epigenetic changes underlie many normal developmental processes, and can lead to disease development as well. While epigenetic effects have been studied in well-characterized rodent models, less research has been done using agriculturally important domestic animal species. This review will present the results of current epigenetic research using farm animal models (cattle, pigs, sheep and chickens). Much of the work has focused on the epigenetic effects that environmental exposures to toxicants, nutrients and infectious agents has on either the exposed animals themselves or on their direct offspring. Only one porcine study examined epigenetic transgenerational effects; namely the effect diet micronutrients fed to male pigs has on liver DNA methylation and muscle mass in grand-offspring (F2 generation). Healthy viable offspring are very important in the farm and husbandry industry and epigenetic differences can be associated with production traits. Therefore further epigenetic research into domestic animal health and how exposure to toxicants or nutritional changes affects future generations is imperative.  相似文献   

Normal color variations of the canine ocular fundus,a retrospective study in Swedish dogs     

Marie IKS Granar  Bo R Nilsson  Helene L Hamberg-Nystr?m 《Acta veterinaria Scandinavica》2011,53(1):13

Background

A retrospective study was made to demonstrate normal variations of the color and size of the tapetal area and color of the nontapetal area in the ocular fundus in dogs, correlating them to breed, age and coat color.

Methods

The study was based on protocols of five hundred and thirty-nine adult dogs describing eye examinations made during the years 1997-2001. The dogs were examined using an indirect ophthalmoscope in order to find heritable eye diseases. The following characteristics were recorded: breed; age; coat color; color and size of the tapetal area and color of the nontapetal area. Normal color variations in the fundus were studied and categorized with regard to breed, age and coat color. Chi-square analysis was used comparing distributions between factors. Differences between mean values were analysed with Student''s t-test or one-way-ANOVA. A logistic regression analysis was performed on the color of the tapetal area with the color of the coat and breed.

Results

Twenty breeds were represented. The mean age was 42.8 months. The most common colors of the tapetal area were yellow-green and orange, and the most common colors of the nontapetal area were dark brown and black. The analysis revealed that coat-color and breed concomitantly did not significantly influence tapetal color. Brown coated dogs often had a striped red and brown nontapetal area. The color of the tapetal area influenced the color of the nontapetal area. Smaller-sized breeds (such as Papillon) had a smaller tapetal area. A tapetal area was completely absent in 1.9%. The age did not influence the color of the tapetal area.

Conclusions

Color of the tapetal area was influenced by both coat color and breed, but neither of these was statistically more influential than the other. The color of the tapetal area influenced the color of the nontapetal area. The size of the tapetal area correlated to breed and to body size.  相似文献   

Sweden considers more oversight of research     

Rose J  Nilsson A 《Science (New York, N.Y.)》1999,283(5409):1829

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Quantification of chemical sulphur species in bulk soil and organic sulphur fractions by S K‐edge XANES spectroscopy     

K. Boye  G. Almkvist  S. I. Nilsson  J. Eriksen  I. Persson 《European Journal of Soil Science》2011,62(6):874-881

A new data treatment method for fitting spectra obtained by sulphur (S) K‐edge X‐ray absorption near‐edge structure (XANES) spectroscopy was used to quantify the chemical S speciation at three experimental sites with arable soils receiving the same long‐term field treatments. Two treatments, crop residue (CR) incorporation and farmyard manure (FYM) application, with equal applications of mineral nutrients were included in the study. In the new data treatment method, internally calibrated spectra of dilute solutions (30 mm ) of model compounds were used to fit the sample spectra. This greatly enhanced the reliability of quantitative determination of contributing S species in soil samples and soil extracts. The results indicated that long‐term FYM application shifted S species composition from highly oxidized towards intermediate oxidization in two of the soils, but in the third soil the opposite trend was observed. Sulphur XANES spectroscopy of acetylacetone extracts of physically protected and unprotected organic S in two of the soils revealed that physical protection was not related to S speciation; however, intermediate forms of oxidized S species appeared to accumulate in the residual S pool (not extractable by acetylacetone).  相似文献