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21.
Roaming mechanisms have recently been observed in several chemical reactions alongside trajectories that pass through a traditional transition state. Here, we demonstrate that the visible light-induced reaction NO(3) → NO + O(2) proceeds exclusively by roaming. High-level ab initio calculations predict specific NO Λ doublet propensities (orientations of the unpaired electron with respect to the molecular rotation plane) for this mechanism, which we discern experimentally by ion imaging. The data provide direct evidence for roaming pathways in two different electronic states, corresponding to both previously documented photolysis channels that produce NO + O(2). More broadly, the results raise intriguing questions about the overall prevalence of this unusual reaction mechanism.  相似文献   
22.
Reasons for performing study: In horses, aortic sinus of Valsalva aneurysms or tears in the aortic root are well‐recognised conditions in breeding stallions, often leading to sudden death. A more uncommon form of aortic rupture, located proximal to the ligamentum arteriosum has been reported in 3 Friesian horses. Objectives: The purpose of this study was to phenotypically characterise aortic rupture and aorto‐pulmonary fistulation in Friesian horses in terms of clinical and post mortem data based on 24 cases. Methods: Friesian horses that were diagnosed with aortic rupture and aorto‐pulmonary fistulation over a period of 13 years (1997–2010) at the Department of Equine Sciences of Utrecht University (n = 15) and Wolvega Equine Hospital (n = 9), were included in this study. Case history, results of clinical examination and gross post mortem findings were screened and analysed. Results: Some cases were found dead without prior symptoms, but in several cases signs such as recurrent colic, peripheral oedema and sustained tachycardia were present for several weeks prior to cardiac failure. Clinical examination during hospitalisation revealed increased rectal temperature, peripheral oedema and increased jugular pulse with a bounding arterial pulse. In the majority of horses an aortic rupture of the aortic arch near the ligamentum arteriosum, concurrent with a circumferential cuff of perivascular haemorrhage and aorto‐pulmonary fistulation, was found at post mortem examination. Conclusions: Aorto‐pulmonary fistulation in conjunction with aortic rupture is more common in Friesians than previously estimated. In some cases findings demonstrate a progressive pathology rather than acute cardiac failure and sudden death. An appropriate approach is necessary during post mortem examination of the heart in order not to overlook the diagnosis. Potential relevance: Equine practitioners should realise that in Friesian horses presented with a history of recurrent false colic, coughing, sustained tachycardia and/or peripheral oedema, aortic rupture and aorto‐pulmonary fistulation should be included in the differential diagnosis.  相似文献   
23.
AIM: To describe a disease of muscle in Charolais calves and confirm the putative diagnosis of inherited myophosphorylase deficiency.

METHODS: Variously stained paraffin sections of muscle prepared from affected calves were used to describe the lesions. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) test was developed and applied to affected calves, their sires, dams and other individuals.

RESULTS: The lesions were those of rhabdomyolysis of skeletal muscles and sub-sarcolemmal spaces in normal fibres. The PCR-RFLP test confirmed the expected mutation for phosphorylase deficiency of Charolais cattle in two affected calves. In addition, sires, dams and other closely-related individuals of four affected calves tested as heterozygous for the mutation. Other apparently unrelated animals also tested as heterozygous.

CONCLUSIONS: The diagnosis of myophosphorylase deficiency was confirmed. The PCR-RFLP test is suitable for use in controlling this recessively-inherited disorder as it can diagnose heterozygous individuals that are otherwise clinically normal.  相似文献   
24.
In 45 primiparous sows, we examined endocrine, ovarian and reproductive responses to split-weaning or five injections per day of 800 ng GnRH from 18 to 21 days of lactation. There was no effect of treatment on absolute or changes in sow weight or backfat depth during lactation. Average piglet growth rates were similar among treatments except that piglets suckling split-weaned sows grew faster (p < 0.05) during days 18–21. On day 18, mean plasma LH concentrations and LH pulse frequency remained relatively stable in conventionally weaned sows but increased (p < 0.01) in response to split-weaning and GnRH. Prior to weaning on day 21, mean plasma LH concentrations remained elevated in GnRH-treated sows but had returned to control levels in split weaned sows. There was no treatment effect on preweaning LH pulse frequency noted on day 21. Weaning was associated with an increase in plasma LH concentrations in all the treatment groups. Mean plasma IGF-I remained relatively constant in conventionally weaned and GnRH sows, decreased in response to split weaning on day 18 (p < 0.02), but were elevated (p < 0.03) in split wean sows on day 21. On the day after weaning, split wean sows had more (p < 0.04) ovarian follicles ≥3 mm than conventionally weaned sows, with GnRH sows being intermediate. The wean-to-oestrus interval was reduced in split-wean sows compared with those conventionally weaned (p < 0.01), with GnRH sows being intermediate. There was no effect of treatment on ovulation rates, numbers of embryos, or embryonic survival rates. These data indicate that split-weaning of litters results in a more rapid return to oestrus after weaning and that this effect is associated with a transient acute increase in circulating gonadotrophins and earlier resumption of ovarian follicular development.  相似文献   
25.
Global climate change has caused phenology change of vegetation.This is especially obvious in urban area.This paper reveals response mechanism of spring phenology of main gymnosperm in Harbin City proper to climate change based on relationship study between two typical phenophases(beginning of bud burst and beginning of leaf expansion) of Korean pine(Pinus koraiensis),Koyama spruce(Picea koraiensis Nakai),needle fir(Abies nephrolepis) and Pinus sylvestnis var.mongolica Litv.and the temperature of every ten ...  相似文献   
26.
Fire is an important ecological process in many western U.S. coniferous forests, yet high fuel loads, rural home construction and other factors have encouraged the suppression of most wildfires. Using mechanical thinning and prescribed burning, land managers often try to reduce fuels in strategic areas with the highest fuel loads. Riparian forests, however, are often designated as areas where only limited management action can take place within a fixed-width zone. These highly productive forests have developed heavy fuel loads capable of supporting stand-replacing crown fires that can alter wildlife habitat and ecosystem function, and contribute to stream channel erosion. Objectives of this study were to determine whether adjacent coniferous riparian and upland forests burned historically with different frequencies and seasonalities, and whether these relationships varied by forest, site, and stream characteristics. We measured dendrochronological fire records in adjacent riparian and upland areas across a variety of forest, site and stream conditions at 36 sites in three sampling areas in the northern Sierra Nevada.  相似文献   
27.
A 2‐year‐old, female Persian cat was presented with a history of distocia. In her first pregnancy, she had whelped four kittens and had eaten all of them right after parturition. She had mated again with the same tomcat. Well‐developed foetuses with weak foetal heart beats were observed in the ultrasonographic examination. En block ovariohysterectomy was performed. Three live and mature foetuses were obtained from the uterus; two of them were female foetuses and had no anatomical problem but the third one exhibiting multiple malformations was a male and diagnosed as ‘schistosoma reflexum’ (SR). The vertebral column deviated markedly to the right (scoliosis) at thoracolumbar region, and the middle lumbar and the sacral vertebrae were directed dorsocranially (lordosis). The entire small intestine, a part of large intestine, stomach, spleen and the right kidney were displayed out of the body, and it seemed that the listed internal organs were protruded from an abdominal cleft associated with the allantoic membrane. Liver, lungs and heart were hypoplastic. The large intestine was seen to have blind end (atresia recti), but anus was normal. Cerebrum and cerebellum were noticed as normal in sizes. Chromosome preparations from lymphocyte cultures of the foetus showed chromosomal aberrations including chromatid and chromosome breaks, exchange figures, non‐homologous pairing, whereas no abnormalities were detected in the chromosome preparations from mother’s cultures. This is probably the first case of SR in a cat, which was examined in detail from clinical, pathological, radiological and chromosomal angles.  相似文献   
28.
An experiment involving 560 crossbred pigs (28 replications of 4 to 6 pigs per pen) was conducted at 9 research stations to assess the effects of dietary concentrations of corn distillers dried grains with solubles (DDGS) on pig performance and belly firmness. Fortified corn-soybean meal diets containing 0, 15, 30, or 45% DDGS were fed in 3 phases from 33 to 121 kg of BW. A common source of DDGS containing 90.1% DM, 26.3% CP, 0.96% Lys, 0.18% Trp, 9.4% crude fat, 34.6% NDF, 0.03% Ca, and 0.86% P was used at each station. Diets were formulated to contain 0.83, 0.70, and 0.58% standardized ileal digestible (SID) Lys during the 3 phases with diets changed at 60 and 91 kg of BW, respectively. The DDGS replaced corn and soybean meal, and up to 0.172% Lys and 0.041% Trp were added to maintain constant SID concentrations of Lys and Trp in each phase. At each station, 2 pigs from each pen in 2 replications were killed and a midline backfat core was obtained for fatty acid analysis and iodine value. In most instances, there were differences among stations (P < 0.01), but the station × treatment interactions were few. Body weight gain was linearly reduced in pigs fed the greater amounts of DDGS (0 to 45%) during phase I (950, 964, 921, and 920 g/d; P < 0.01) and over the entire experimental period (944, 953, 924, and 915 g/d; P = 0.03), but ADFI (2.73, 2.76, 2.68, and 2.70 kg) and G:F (347, 347, 345, and 341 g/kg) were not affected (P = 0.15 and P = 0.33, respectively) during the entire test. Backfat depth was reduced (linear, P < 0.02) by increasing amounts of DDGS (22.5, 22.7, 21.4, and 21.6 mm), but LM area (47.4, 47.4, 46.1, and 45.4 cm(2)) was not affected (P = 0.16) by treatments. Estimated carcass fat-free lean was 51.9, 52.2, 52.4, and 52.1% for 0 to 45% DDGS, respectively (linear, P = 0.06). Flex measures obtained at 6 stations indicated less firm bellies as dietary DDGS increased (lateral flex: 11.9, 8.6, 8.4, and 6.6 cm; linear, P < 0.001; vertical flex: 26.1, 27.4, 28.2, and 28.7 cm; linear, P < 0.003). Saturated and monounsaturated fatty acid concentrations in subcutaneous fat decreased linearly (P < 0.001) and PUFA concentrations increased linearly (P < 0.001) with increasing DDGS in the diet. Iodine values in inner (61.1, 68.2, 74.7, and 82.2) and outer (67.9, 73.6, 79.6, and 85.8) backfat increased linearly (P < 0.001) as DDGS in the diet increased. In this study, feeding diets with 30 or 45% DDGS did not have major effects on growth performance, but resulted in softer bellies. Regression analysis indicated that iodine values increased 4.3 units for every 10 percentage unit inclusion of DDGS in the diet.  相似文献   
29.
Botanical features of "YX-1" reproductive organ and bearing rate by number of pollen granules in pollen sacs of Lycium chinensis was observed and researched through field investigation, smear preparation and paraffin sections. YX-1 of Lycium chinensis was determined as incomplete male sterility and further classified into complete sterile type, sterile type I and sterile type II. The fertility standard of male sterility of Lycium chinensis was preliminarily proposed to establish a basis for crossbreeding of male sterility of Lycium chinensis.  相似文献   
30.
基于RAGA的投影寻踪模型在土壤重金属污染评价中的应用   总被引:2,自引:0,他引:2  
将投影寻踪分类模型(PPC)应用于土壤环境质量综合评价中,利用基于实码的加速遗传算法(RAGA)来优化投影方向,将多维数据指标转换成低维子空间,通过寻求最优投影方向来计算投影函数值,从而根据投影值的大小进行土壤综合评价。并结合实例进行了应用,其结果合理,避免了权重确定的人为干扰,为土壤环境质量评价提供了一条新的方法和思路。  相似文献   
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