Crystalline structure of heat-treated Scots pine [<Emphasis Type="Italic">Pinus sylvestris</Emphasis> L.] and Uludağ fir [<Emphasis Type="Italic">Abies nordmanniana</Emphasis> (Stev.) subsp. <Emphasis Type="Italic">bornmuelleriana</Emphasis> (Mattf.)] wood     

Mehmet Akgül  Esat Gümüşkaya  Süleyman Korkut 《Wood Science and Technology》2007,41(3):281-289

The aim of this study was to determine changes in crystallinity and crystalline unit cell type of heat-treated Scots pine (Pinus sylvestris L.) and Uludağ fir (Abies nordmanniana stev. subsp. bornmuelleriana Mattf.) wood samples by means of FT-IR spectroscopic method. Heat treatment was applied on the test samples in an oven at three different temperatures (120, 150, and 180°C) and for two different periods of time (6 and 10 h) under atmospheric pressure. It was designated that crystallinity of both Scots pine and Uludağ fir wood samples increased during heat treatment depending on the duration. However, monoclinic structure in crystalline unit cells of Scots pine and Uludağ fir wood samples converted to triclinic structure when heat treated. It was estimated that monoclinic structure was dominant in the crystalline unit cell. It was established that the crystalline structure of Scots pine wood samples was more affected by heat treatment than that of Uludağ fir wood samples.  相似文献   

Sapstain fungi on <Emphasis Type="Italic">Pinus radiata</Emphasis> logs – from New Zealand Forest to export in Japan     

Joanne M.?Thwaites  Roberta L.?FarrellEmail author  Kunio?Hata  Peter?Carter  Marco?Lausberg 《Journal of Wood Science》2004,50(5):459-465

Supply of clear, unstained logs from an export country is important economically as well as in reducing the biosecurity risk to an importing country such as Japan. Although conditions found within the holds of ships containing logs are thought to be ideal for rapid colonization of sapstain fungi, no research has been conducted. Research-focussed log export trials were designed to determine the extent of sapstain colonisation at specific points in the processing of logs from harvesting to arrival at the export destination. Two trials were established, in the austral summer and winter, in which mature Pinus radiata logs were harvested in New Zealand and shipped to export ports in Japan. Data loggers placed above and below deck of the ships recorded microclimatic conditions. Nine species of sapstain fungi were isolated from logs during the summer trial; the most common species isolated were Ophiostoma floccosum, Ophiostoma querci, and Ophiostoma setosum. In contrast, ten sapstain species were detected during the winter trial, with Sphaeropsis sapinea, O. querci, O. floccosum, and O. setosum most commonly isolated. This research was the first successful attempt at measuring visual sapstain development and isolating sapstain fungi from the time of harvesting to arrival at an export destination.  相似文献   

Effect of temperature and compression on the mechanical behavior of steam-treated wood   总被引：2，自引：0，他引：2  

Petri P. KÄrenlampi  Pekka TynjÄlÄ  Pasi StrÖm 《Journal of Wood Science》2003,49(4):298-304

The mechanical behavior of steamed spruce wood changes dramatically with compression along the grain, the change being much more moderate perpendicular to the grain. The stiffness decrement due to increased temperature is greatest in the tangential material direction. The stiffness decrement due to compression is greatest along the grain. Compression to 80% compressive strain at 131°C inverts the order of the material directions regarding stiffness, the stiffness being the least along the grain. Plastic strain due to compression is greater at higher temperatures. The compression-induced decrement of stiffness along the grain is greater at higher temperatures, but the off-axis decrement of stiffness is less at higher temperatures.  相似文献   

Genetic diversity of Populus euphratica populations in northwestern China determined by RAPD DNA analysis   总被引：1，自引：0，他引：1  

Saito  Y.  Shiraishi  S.  Tanimoto  T.  Yin  L.  Watanabe  S.  Ide  Y. 《New Forests》2002,23(2):97-103

Five Populus euphratica Oliver populations in northwestern China were analyzed using RAPD DNA markers to determine genetic diversity among and within populations. One hundred-and-five polymorphic bands were observed, ranging in size from 250 bp to 1700 bp, using 10 primers. Only one population on the north side of the Tianshern Range had a unique band common to all individuals that was not found in individuals from populations in the Tarim River valley. Intra-population genetic diversity was high in two populations along the Tarim River and low in the other three populations. There was no significant correlation between genetic distances and geographic distances. The result of correspondence analysis shows that the individuals from the three populations with low genetic diversity are isolated from each other. The result of cluster analysis based on genetic distance shows that the population in the Tianshern Range is genetically distant from the other populations. These results suggest that the Tianshern Range population was genetically isolated from the other populations.  相似文献   

The impact of human activity on the biomass allocation of a medicinal herbaceous species in an agroforestry system of Southwest China     

J. Zhang  T. Shen  Y. L. Zhao  H. Jin  L. H. Wu  H. G. Liu  Y. Z. Wang 《Agroforestry Systems》2015,89(3):469-476

  相似文献   

Benefit–cost analysis of a white spruce clonal seed orchard in New Brunswick,Canada     

Y. Q. Wu  Y. H. Weng  C. Hennigar  M. S. Fullarton  V. Lantz 《New Forests》2015,46(1):141-156

  相似文献   

改善生猪宰前管理减少应激反应的措施     

谭雅  王远亮 《中国动物检疫》2015,32(10):70-71

本文针对生猪宰前在饲喂、驱赶、运输、装卸、致晕和待宰等环节影响猪肉品质的主要应激因素,基于相关研究报道,提出了宰前禁食、温柔驱赶、科学运输和装卸、选择CO2击晕和最佳待宰环境、宰前添加抗应激药物等改善宰前管理减少应激反应的措施,最终强调合理宰前管理和致晕方法对保证猪肉质量至关重要。  相似文献   

Reduced high intensity training distance had no effect on VLa4 but attenuated heart rate response in 2-3-year-old Standardbred horses     

Sara Ringmark  Arne Lindholm  Ulf Hedenstr?m  Michael Lindinger  Kristina Dahlborn  Clarence Kvart  Anna Jansson 《Acta veterinaria Scandinavica》2015,57(1)

Background

Training of Standardbred race horses aims to improve cardiovascular and metabolic functions but studies on the effects of different training strategies from breaking till racing are lacking. Sixteen horses with the goal to race as 3-year-olds were studied from breaking (1-year-olds) to December as 3-year-olds. Horses were allocated to either a control (C) or reduced (R) training program from 2 years of age. The aim was to evaluate the effect of reducing the distance of high intensity exercise by 30% with respect to velocity at lactate concentration 4 mmol/l (V_La4), blood lactate and cardiovascular response. All training sessions were documented and heart rate (HR) was recorded. A standardized exercise test of 1,600 m was performed 10 times and a V_La4 test was performed five times.

Results

C horses initially exercised for a longer time with a HR >180 beats per minute compared to R horses (P < 0.05) but after 6–9 months, time with HR >180 bpm decreased in C and were similar in the two groups (P > 0.05). Over the 2-year period, recovery HR after the 1,600 m-test decreased in both groups but was within 2 months lower in C than in R (P < 0.05). C horses also had lower resting HR as 3-year-olds (P < 0.01) than R horses. In C, post exercise hematocrit was higher than in R (P < 0.05). There was a tendency (P < 0.1) towards a larger aortic diameter in C as 3-year-olds (C: 1.75 ± 0.05, R: 1.70 ± 0.05 cm/100 kg BW). Left ventricle diameter and blood volume (in December as 2-year-olds) did not differ between groups. There were no differences between groups in post exercise blood lactate concentration or in V_La4. Both groups were equally successful in reaching the goal of participation in races.

Conclusions

Horses subjected to a reduced distance of high intensity training from the age of 2 showed an attenuated heart rate response, but were able to maintain the same V_La4 and race participation as horses subjected to longer training distances.  相似文献   

Factors affecting costs for on-farm control of salmonella in Swedish dairy herds     

Estelle C.C. ?gren  Jan Johansson  Jenny Fr?ssling  Helene Wahlstr?m  Ulf Emanuelson  Susanna Sternberg-Lewerin 《Acta veterinaria Scandinavica》2015,57(1)

Background

The Swedish control program for salmonella includes restrictions and on-farm control measures when salmonella is detected in a herd. Required control measures are subsidised by the government. This provides an opportunity to study costs for on-farm salmonella control. The aim of this study was to describe the costs for on-farm salmonella control in Swedish cattle herds and to investigate the effects of herd factors on these costs in dairy herds.

Results

During the 15 years studied there had been a total of 124 restriction periods in 118 cattle herds; 89 dairy herds, 28 specialised fattening herds and three suckler herds. The average costs per herd for on-farm salmonella control was 4.60 million SEK with a median of 1.06 million SEK corresponding to approximately 490 000 and 110 000 EUR. The range was 0.01 to 41 million SEK corresponding to 1080 EUR to 4.44 million EUR per farm. The costs cover measures required in herd-specific control plans, generally measures improving herd hygiene. A mixed linear model was used to investigate associations between herd factors and costs for on-farm salmonella control in dairy herds. Herd size and length of the restriction period were both significantly associated with costs for on-farm control of salmonella with larger herds and longer periods of restrictions leading to higher costs. Serotype detected and administrative changes in the Swedish Board of Agriculture aiming at reducing costs were not associated with costs for on-farm salmonella control.

Conclusions

On-farm control of salmonella in Swedish cattle herds incurred high costs but the costs also varied largely between herds. Larger herds and longer restriction periods increased the costs for on-farm control of salmonella in Swedish dairy herds. This causes concern for future costs for the Swedish salmonella control program as herd sizes are increasing.  相似文献   

Toxicokinetics of T‐2 toxin and its major metabolites in broiler chickens after intravenous and oral administration          下载免费PDF全文

Y. X. Sun  X. Yao  S. N. Shi  G. J. Zhang  L. X. Xu  Y. J. Liu  B. H. Fang 《Journal of veterinary pharmacology and therapeutics》2015,38(1):80-85

  相似文献