程序升温-气相色谱技术同时检测饲料中10种防腐剂

实验采用DB-5MS毛细管柱结合程序升温技术的气相色谱法在7 min内同时分离和检测了饲料中丙酸（PA）、山梨酸（SA）、苯甲酸（BA）、脱氢乙酸（DHA）、对羟基苯甲酸甲酯（MP）、对羟基苯甲酸乙酯（EP）、对羟基苯甲酸丙酯（PP）、对羟基苯甲酸丁酯（BP）、对羟基苯甲酸异丙酯（IPP）、对羟基苯甲酸异丁酯（IBP）等10种防腐剂。结果表明,10种添加剂的线性相关系数r≥0.9989,检测限为0.1～5μg/mL,样品平均回收率为81.5%～90.0%,相对标准偏差小于5.0%。     

江门市城区行道树碳储量

采用材积源-生物量法（Volume-Biomass Method）对江门市行道树的碳储量进行研究。计算了芒果Mangifera indica、高山榕Ficus altissima、美丽异木棉Chorisia speciosa、蒲葵Livistona chinensis、海南红豆Ormosia pinnata、尾叶桉Eucalyptus urophylla、乌墨Syzygium cumini和火焰树Spathodea campanulata等8种行道树的立木碳储量,进而估算江门市城区行道树的碳储量。结果表明：江门市主要行道树平均树高8.92±0.19 m,平均胸径23.18±0.49 cm,平均蓄积量0.22±0.01 m3,生物量为5166.69 t,碳储量为2546.75 t,单株碳储量乌墨最高。可见行道树具有重要的碳汇功能,对改善江门市的城市生态环境有积极的作用。     

Prediction of enteric methane production from dairy cows

Abstract

The main objective of this study was to elucidate the potential for prediction of enteric methane (CH₄) emissions from dairy cows by using predicted rumen plus hindgut digested (fermented nutrients) and total tract digested nutrients (by using NorFor) as input variables. Twenty-one experiments (78 dietary treatments) were collected. The data-set was used to develop prediction models and to test their and extant models ability to predict enteric CH₄ emissions. Models were compared based on mean squared prediction error and concordance correlation coefficient (CCC) analysis. Fermented nutrients did not predict enteric CH₄ emissions adequately (CCC < 0.420). Including total digested (td) nutrients in the model [CH₄ (MJ/d) = ?2.13 + 1.64 tdOM (kg/d) ?9.74 tdFat (kg/d) + 1.64 tdNDF (kg/d)] predicted enteric CH₄ emissions more precisely (CCC = 0.733), and showed an improvement in the prediction of enteric CH₄ emissions over the extant models tested.     

大涝坝凝析气藏注气驱相态模拟

指出了大涝坝高含凝析油凝析气藏衰竭式开发过程中,当地层压力下降至低于露点压力,地层出现反凝析现象,特别是近井地带压降漏斗的存在,析出的凝析油更多,严重污染了井筒周围的储层,造成渗流阻力增大,致使气井产能递减快。结合数值模拟研究表明:注气能有效降低凝析气藏反凝析油的析出,改善其开发效果,为注气提高采收率提供理论依据。     

Physiology and Regulation of Seasonal Nitrogen Cycling in Woody Plants

Summary

Seasonal nitrogen cycling in trees is a mechanism for conserving and reusing nitrogen that may contribute to nitrogen use efficiency. In this review the physiological and molecular regulation of seasonal nitrogen storage is examined. Research using the 32 kDa bark storage protein gene, bspA of poplar (Populus) as a model system has revealed important facets regulating gene expression and subsequent nitrogen storage. Recent progress has demonstrated that bspA expression is a photoperiod response mediated by phytochrome and secondary messengers including Ca²⁺ and protein phosphorylation are involved in signaling pathways. Furthermore, evidence indicates that photoperiod modulated expression likely involves metabolic signaling mediated by glutamine and sucrose. A model is proposed that integrates the various facets of poplar bspa expression.     

The Effect of Elevated Atmospheric CO2 Concentration on Two Populus Clones Grown in a FACE System

SUMMARY

Two poplar clones, hybrid Populus deltoides Bartr. Ex Marsh X Populus nigra L. (Populus xeuramericana), clone I-214, and Populus deltoides, clone Lux, were grown from hardwood cuttings for one growing season in either ambient (360 μmol mol^?1) or elevated (560 μmol mol^?1) [CO₂] in FACE-systemrings at Rapolano Terme (Siena, Italy). Both clones I-214 and Lux exhibited a higher aboveground bio-mass, photosynthesis at light saturation and instantaneous transpiration efficiency (ITE) in CO₂-enriched air. The elevated [CO₂]-induced responses of clone I-214 included increased investment in branch and leaf biomass, and enhanced stem volume. The elevated [CO₂]-induced responses of clone Lux included an increase in the number of branches (and foliage area). Indication of photosynthetic acclimation under elevated [CO₂] was found during the early morning, but only in clone I-214. Stomatal conductance decreased under elevated [CO₂] particularly in clone Lux. Clone differences in response to elevated [CO₂] should be taken in account when planning future poplar plantations in forecast warmer and drier Mediterranean sites.     

Effects of intensification of pastoral farming on greenhouse gas emissions in New Zealand

Abstract

AIMS: The aims of this cross-sectional study were to investigate the herd and cow-level prevalence of bovine digital dermatitis (BDD) in dairy farms in the northern Taranaki region of New Zealand, and to identify whether there was any spatial clustering of herds with the disease.

METHODS: A survey of 224 dairy farms in the northern Taranaki region of New Zealand was undertaken from September 2014 to February 2015. Following training in robust criteria to confirm BDD visually, a technician inspected the rear feet of every milking cow on the farms during milking. The identity of cows with lesions and the feet involved were recorded. The proportion of cows affected among the inspected population (cow-level prevalence), the proportion of a herd affected (farm-level prevalence), and proportion of farms with ≥1 cow with lesions, were calculated. A bivariate K function analysis was then used to assess whether farms with ≥1 cow with lesions were clustered, after accounting for the distribution of the farms involved in the study.

RESULTS: Bovine digital dermatitis lesions were observed on 143/224 (63.8 (95% CI=57.5–70.1)%) farms. Within-farm prevalence was 0% on 81 (36.2%) farms, between >0 and <3% on 120 (53.5%) farms, with a maximum prevalence of 12.7% on one farm. Overall, cow-level prevalence was 707/60,455 (1.2 (95% CI=0.9–3.0)%), and on affected farms was 707/41,116 (1.7 (95% CI=1.4–2.1)%). In affected cows, 268/707 (37.9%) had a lesion on left foot only, 262/707 (37.1%) on the right foot only and 177/707 (25.0%) on both feet. The K function analysis showed no evidence of clustering of farms with BDD.

CONCLUSIONS: Bovine digital dermatitis was widespread among the survey farms, but there was no evidence that there was any clustering of herds with BDD. The cow-level prevalence on affected farms was much lower than reported elsewhere.

CLINICAL RELEVANCE: Although the prevalence at the cow level was low, if these data are representative of other regions of New Zealand, BDD could easily become a major problem on dairy farms in New Zealand, as has been observed in other countries.     

Mucopolysaccharidosis type VI in a Miniature Poodle-type dog caused by a deletion in the arylsulphatase B gene

Abstract

AIM: To investigate and characterise an inborn error of metabolism in a dog with skeletal and ocular abnormalities.

METHODS: A 2.5-year-old small male Miniature Poodle-like dog was presented with gross joint laxity and bilateral corneal opacities. Clinical examination was augmented by routine haematology, serum chemistry, radiographs, pathology, enzymology and molecular genetic studies. Euthanasia was requested when the dog was 3 years of age because of progressively decreasing quality of life.

RESULTS: Radiology revealed generalised epiphyseal dysplasia, malformed vertebral bodies, luxation/subluxation of appendicular and lumbosacral joints with hypoplasia of the odontoid process and hyoid apparatus. These clinical and radiographic findings, together with a positive urinary Berry spot test for mucopolysaccharides, and metachromatic granules in leucocytes, were indicative of a mucopolysaccharidosis (MPS), a lysosomal storage disease. Histological lesions included vacuolation of stromal cells of the cornea, fibroblasts, chondrocytes, macrophages and renal cells. The brain was essentially normal except for moderate secondary Wallerian-type degeneration in motor and sensory tracts of the hind brain. Dermatan sulphate-uria was present and enzymology revealed negligible activity of N-acetylgalactosamine-4-sulphatase, also known as arylsulphatase B, in cultured fibroblasts and liver tissue. A novel homozygous 22 base pair (bp) deletion in exon 1 of this enzyme's gene was identified (c.103_124del), which caused aframe-shift and subsequent premature stop codon. The “Wisdom pure breed-mixed breed” test reported the dog as a cross between a Miniature and Toy Poodle.

CONCLUSIONS: The clinicopathological features are similar to those of MPS type VI as previously described in dogs, cats and other species, and this clinical diagnosis was confirmed by enzymology and molecular genetic studies. This is an autosomal recessively inherited lysosomal storage disease.

CLINICAL RELEVANCE: The prevalence of MPS VI in Miniature or Toy Poodles in New Zealand and elsewhere is currently unknown. Due to the congenital nature of the disorder, malformed pups may be subject to euthanasia without investigation and the potential genetic problem in the breed may not be fully recognised. The establishment of a molecular genetic test now permits screening for this mutation as a basis to an informed breeding policy.     

工业园区恶臭污染现状及来源分析

首先分析了苏州工业园区内恶臭污染现状,然后介绍了苏州工业园区内恶臭形成的几种原因。