关于“农业运输问题的一个新算法”的注记

针对运输表,提出第2类闭矩形和第2类对角运量调整以及第3类闭矩形和第3类对角运量调整的概念,从而得出求解变量有上界的运输问题的对角运量调整法,并给出了具体的实例。     

武汉市销地批发市场蔬菜价格与交易量短期波动分析

探究蔬菜价格与交易量的波动规律对调控蔬菜生产与流通具有重要的理论与现实意义.选取3个代表性的蔬菜品种的日交易价格和交易量面板数据为研究时象,分析了3个蔬菜品种的价格和交易量渡动的基本特征,并且采用"速度法"对其波动规律进行了系统地分析.结果表明,郊区蔬菜的供给正逐年减少,并在很大程度上影响了蔬菜价格和交易量的波动;外地蔬菜的交易量渡动频繁,无明显周期性规律,且波幅也不稳定;外菜和郊菜的交替上市保证了市场的稳定.针对具体研究结果,分别从农户和政府的角度提出了相应的建议.     

大叶芹染色体的核型分析

采用根尖压片法对大叶芹体细胞染色体计数，并对其核型进行了分析。结果表明：大叶芹的染色体数目为2n=22；核型公式为2n=2x=22=14sm＋8st，属于3B型。全组染色体总长92．80μm，长臂总长为66．83μm，核型不对称系数为72．02％。染色体总体积为264．40μm^3。     

透光抚育对长白山“栽针保阔”红松林群落结构和凋落物影响

[目的]为加快阔叶红松林恢复,完善"栽针保阔"恢复理论体系,并为阔叶红松林恢复实践提供科学依据。[方法]运用采伐试验方法,研究上层透光抚育(对照-栽针未采伐、轻度采伐-25%、中度采伐-50%、强度采伐-75%、皆伐-100%,采伐强度是指蓄积比例)对长白山中期(33年)"栽针保阔"红松林群落结构、群落蓄积量及凋落物的影响规律。[结果]①随着择伐强度增大,红松的重要值逐渐上升(0.364%~0.732%),红松在群落中的优势地位逐渐上升,而阔叶树种重要值却不断下降。②轻、中度择伐较对照凋落物量(6.11±0.42~7.45±0.79 t/hm2)显著提高了8.6%和13.7%(P0.05),强度择伐和皆伐降低1.2%和6.7%,但仅皆伐降低显著(P0.05);对于凋落物碳储量,中度择伐使其凋落物碳储量(2.13±0.39~2.82±0.37 t/hm2)较对照提高19.5%(P0.05),皆伐使其降低9.8%(P0.05)。③皆伐、强度择伐、中度择伐和轻度择伐蓄积量(221.2~260.6 m3/hm2)较对照群落分别提高了26.9%、19.5%、15.9%和7.7%,且均与对照之间存在显著差异(P0.05)。而对于红松蓄积量(36.6~184.4 m3/hm2),皆伐、强度择伐、中度择伐、轻度择伐依次较照样地提高了5.0、4.1、2.8、1.9倍,且均与对照有显著差异(P0.05)。[结论]从促进林分稳定性、维持凋落碳储量及提高森林的生态效益综合考虑,采伐强度应以中低度透光方式为宜。     

尾叶桉类树种二元立木材积模型的编制

采用151株建模样本,以山本式固定参数方程和可变参数方程建立了广东省尾叶桉类树种二元立木材积模型,模型自检及59株检验样木验证表明,固定参数模型和可变参数模型两精度符合要求,能满足生产需要,但后者具有更优的适用性能。     

安徽省饲料玉米贸易及其与畜牧业发展之间的关系

对安徽省饲料玉米的商贸情况及其与畜牧业发展之间的关系进行了调查。结果表明,安徽省2008年饲料行业的玉米需求量为114.157万t,全省养殖业的玉米需求量达683.737万t,其中通过贸易输入的玉米达397.14万t,通过养殖企业、饲料企业和个体输入的玉米占48.6%。玉米总量与安徽省肉类、奶类产量及牧业总值显著相关,而与禽蛋产量的相关性不显著;该省的玉米产量与肉蛋奶产量及牧业总值无明显的相关性,但通过贸易输入的玉米量与肉类、奶类产量及牧业总值显著相关。     

The volume effect of lidocaine on thoracic epidural anesthesia in conscious Beagle dogs

ObjectiveTo evaluate the volume effect of local anesthetic solution on thoracic epidural analgesia in dogs.Study designProspective, experimental trial.AnimalsFive healthy adult Beagle dogs weighing 9.7 ± 1.3 kg.MethodsA catheter was inserted into the seventh thoracic epidural space using a lumbosacral approach, and secured with suture under total intravenous (IV) anesthesia with propofol. Each dog was administered four volume treatments (0.05, 0.10, 0.15 and 0.20 mL kg⁻¹) of 2% lidocaine via the catheter at 12 hour intervals. In every treatment, dogs were re-anesthetized with propofol (6 mg kg⁻¹, IV) and isoflurane, and received iohexol at each volume to visualize the epidural distribution (ED) through computed tomography. Three hours after epidurography, when dogs had recovered from anesthesia, the appropriate volume of lidocaine was injected through the catheter, and sensory blockade (SB) in dermatomes was evaluated by pinching with a mosquito forceps. Results were presented as median (range), and the volume effect on ED and SB was analyzed with one-way Kruskal–Wallis anova.ResultsIn proportion to volumes (0.05, 0.10, 0.15 and 0.20 mL kg⁻¹), there were significant increases in the extent of ED from 7.4 (5.5–9.0) to 10.4 (8.0–12.0), 13.2 (12.5–13.0), and 15.2 (13.0–18.0) vertebrae, respectively, p < 0.001, and in SB from 2.7 (1.0–5.0) to 6.8 (4.5–10.5), 9.9 (6.5–13.0), and 13.1 (11.0–15.0) dermatomes, respectively, p < 0.001. Unilateral ED and SB were observed in all treatments with various grades, and this distribution was more frequent in the low volume treatments. In the high volume treatments, temporary complications including Horner's syndrome, ataxia, paraplegia, depression, stupor, and intermittent cough occurred often.Conclusions and clinical relevanceThe increase in volume of local anesthetic solution improved SB by resulting in more consistent bilateral dermatome blockade as well as an extended blockade. However, caution should be exerted, as higher volume injections of lidocaine caused side effects in all dogs.     

Eignung eines großen Flüssigkeits‐ und eines Luftpyknometers zur Bestimmung des Rohvolumens von Feststoffen unterschiedlicher Art und Größe

Suitability of a large liquid pycnometer and an air pycnometer to determine the raw volume of solids of different type and size The raw volume of materials, which contain constituents of relatively large size as well as of low density, can not be determined according to ISO 11508 without grinding. Therefore, this study should show if the analysis can be performed on original‐sized materials with a large liquid pycnometer (LP, volume of about 280 cm³) or a self‐made air pycnometer (AP). When materials of particle size up to 16 mm and/or of very different raw density were analyzed with the LP, the differences between parallel measurements were considerably greater than those of fine‐textured soils and than those expected from repeated filling of the LP with water. They are ascribed mainly to the inhomogeneity of the samples and less to measuring errors. Consequently, the LP used seems to be suitable for the determination of particles with constituent size of up to 3 cm. However, the volume determination of every sample has to be performed at least twice. If the results do not meet the required precision, more repetitious measurements have to be performed, or the sample amount has to be enlarged. The same determination with the AP led to comparable and plausible results only in the case of water and of materials with compact constituents of relatively great size mainly (sand and fine gravel), when the samples were oven‐dry, air‐dry, or fairly moist. The results of the other materials were comparable, when the same sample preparation was performed as with liquid pycnometry (heating‐up in water) and when they were covered by water in the measuring cell during measurement. The deviations from LP measurements were reduced, when measuring was performed by increasing air‐pressure conditions (100 hPa) instead of lowering (–300 hPa), but to an insufficient degree. The reason for erroneous results was attributed to the existence of adsorbed air on particle surfaces (dry materials) and the evaporation of water during the measuring step (moist samples), respectively.     

WTO与中国林业投资

中国加入WTO，将对林业投资产生较大的影响，既存在机遇，也面临挑战。外资的引进无疑也会发生一定的变化，同时也将进一步促进中国企业优势项目的再投资。     

Resistance,redistribution, and power in the Fair Trade banana initiative

The Fair Trade movement seeks to alter conventional trade relations through a system of social and environmental standards, certification, and labels designed to help shorten the social distance between consumers in the North and producers in the South. The strategy is based on working both in and against the same global capitalist market that it hopes to alter, raising questions about if and how Fair Trade initiatives exhibit counter-hegemonic potential to transform the conventional agro-food system. This paper considers the multiple levels at which Fair Trade alternatives operate to identify the different forms of social action that the movement engages with, and to clarify where the movements counter-hegemonic potentials are being realized. I suggest the Fair Trade movement is most successful in encouraging consumers and producers to commit acts of resistance and in supporting redistributive action that shifts resources from North to South. Up to now, however, Fair Trade alternatives appear to hold only a theoretical potential to provoke transformative change in the agro-food system. A reconceptualization of the Fair Trade model and how it is implemented could allow it to manifest more of its implicit, oppositional promise.Aimee Shreckis a sociologist and the Research Specialist for the California Faculty Association. Her previous work as a postdoctoral researcher with the University of California, Berkeley and the Sustainable Agriculture Research and Education Program focused on social justice, sustainable agriculture, and fair trade.