洪亮吉的诗歌“代降”论

洪亮吉认为诗歌创作观念与赋比兴传统发生偏离,诗歌创作每况愈下。由此,洪亮吉积极反驳性灵派的盲目追新,其诗歌“代降”论的形成基于对性灵派平俗诗风的不满,同时与乾嘉时期朴学的复古思潮及学者的经世致用思想有密切关系。洪亮吉诗歌“代降”论呼唤《诗经》确立的诗歌传统回归,有救弊时代诗坛的意义。

胡应麟“格以代降”说的诗学意义与文化意义

"格以代降"是胡应麟对古典诗学传统的提炼和总结,不能被简单地视为文学退化论,这是复古派诗论家对于诗的抒情范围越来越滥、"诗言志"的纯粹性不断受到冲击的诗歌发展历程的一种真实描绘和恳切批评,是对传统诗教精神的重新提倡。"格以代降"与中国古代诗歌的"兴寄"传统有关,"格"是一个整体性的诗学概念,既包括情志层面,也包括体式层面,在此语境中更偏重情志。诗格是创作者身份地位和社会阶层在文学艺术中的隐性显现。高格的标准由社会上层决定,传统士大夫所规定、认同和倡导的最高格,兼具了政治意义、文化意义和审美意义。"格以代降"这一命题的本质是主流诗学话语的掌控者或追随者对于自身的精神追求、权力地位和审美趣味的坚持和捍卫。

关于“格以代降”的考辩

胡应麟在《诗薮》中提出来的重要命题"格以代降"是一个极容易产生歧义的命题。学界往往认为该命题就是意味着"文学退化论"。那么"格以代降"是否就只有这一层意思呢?它是否还有其他的含义?这些都值得思考。从"格以代降"的字面意思以及提出此命题的时代背景等方面进行考辩,以求揭示该命题的实质和丰富的内涵。

自适应迭代降剂量技术在克罗恩病CT小肠造影中的临床应用

目的 评价自适应迭代降剂量（AIDR）技术在克罗恩病CT小肠造影中的应用.方法 回顾性分析2013年1-3月间中山大学附属第六医院收治并经炎性肠病多学科诊疗小组确诊为克罗恩病的26例患者的临床和影像资料,所有病例均采用AIDR技术行CT小肠造影检查.由两名诊断克罗恩病经验丰富的放射科医生分别阅片,计算每例患者所受电离辐射总量,并分析克罗恩病影像学特点.结果 26例患者辐射剂量为5.58～12.90（9.00±2.00） mSv,明显低于常规使用剂量（15 mSv）.克罗恩病CT小肠造影检查发现,26例患者中,1例患者处于静止期,另外25例共出现109处节段性肠壁增厚,合并系膜侧淋巴结肿大,同时出现异常强化现象.其中16例发现肠腔狭窄,12例肠壁呈分层样强化,14例出现“梳样征”;8例出现系膜侧脂肪密度增高,7例肠瘘,6例腹腔脓肿,3例肛瘘.结论 低剂量AIDR技术CT小肠造影技术不会损失图像质量,能够有效诊断克罗恩病并明显降低辐射剂量.

《诗薮》的诗歌发展观

"体以代变"、"格以代降"是胡应麟在其诗学专著《诗薮》中提出的诗学发展观,所谓"体以代变",是指中国诗歌的发展变化受时代的制约与影响,"格以代降",是指诗格"一代不如一代"。这是一种精辟的文学史观,虽然承认诗文以代而变的必然趋势,但同时又深深地打上了崇古卑今的烙印。

Research on degradation of 2, 4 dichlorophenol and pentachlorophenol in water by electron beam irradiation

Electron beam was successfully used for the degradation of 2,4-dichlorophenol (2,4-DCP) and pentachlorophenol (PCP) in water. The effects of radiation doses on substrate degradation and dechlorination of solutions with concentrations of 50 mg/L for both chlorophenols were investigated. The effects of initial concentration, pH and absence of oxygen on the degradation were also investigated. The concentrations of 2,4-DCP and PCP remaining in solution after irradiation were measured by high-performance liquid chromatograph (HPLC). The results showed that an increased radiation dose led to increased degradation of the chlorophenols and increased Cl- yields. In all cases, the rate of degradation was found to be higher than the corresponding inorganic chloride yield from the parent compound. Deoxygenation was also found to increase the rate of degradation of the chlorophenols in water while degradation under alkaline condition was lower than at low to neutral pH.

Dimension-down iterative algorithm for the mixed transportation network design problem

An optimal dimension-down iterative algorithm （DDIA） is proposed for solving a mixed （continuous/ discrete） transportation network design problem （MNDP）, which is generally expressed as a mathematical programming with equilibrium constraints （MPEC）. The upper level of the MNDP aims to optimize the network performance via both the expansion of existing links and the addition of new candidate links, whereas the lower level is a traditional Wardrop user equilibrium （UE） model. The idea of the proposed DDIA is to reduce the dimensions of the problem. A group of variables （discrete/continuous） are fixed to altemately optimize another group of variables （continuous/discrete）. Some continuous network design problems （CNDPs） and discrete network design problems （DNDPs） are solved repeatedly until the optimal solution is obtained. A numerical example is given to demonstrate the efficiency of the proposed algorithm.

Effects of Nitric Oxide on the Germination of Wheat Seeds and Its Reactive Oxygen Species Metabolisms Under Osmotic Stress

Effects of sodium nitroprusside (SNP), a nitric oxide (NO) donor, on the germination and metabolism of reactive oxygen species were surveyed in wheat (Triticum aestivum L.) seeds. Germination of wheat seeds and even the elongation of radicle and plumule were dramatically promoted by SNP treatments during the germination under osmotic stress. Meanwhile, activities of amylase and EP were enhanced, thus leading to the degradation of storage reserve in seeds. After osmotic stress was removed, higher viability of wheat seeds was also maintained. In addition, the activities of CAT, APX and the content of proline were increased by SNP treatment simultaneously, but activities of LOX were inhibited, and both of which were beneficial for improving the antioxidant capacity during the germination of wheat seeds under osmotic stress. It was also shown that the increase of the activity of amylase induced by SNP in embryoless half-seeds of wheat in the beginning period of germination (6 h) might be indirectly related to GA(3).

Advances in Molecular Mechanism of Microbiological Degradation of Salicylate

Salicylate is a type of pollutant widely and persistently existed in environ- ment. Microbiological degradation of salicylate as one kind of biological remediation methods has the advantages of low cost, good effect and no secondary pollution, and also attracts wide attention both at home and abroad. Currently, many salicy- late-degrading bacteria are isolated and screened, while the molecular mechanism of salicylate metabolism is also worth deep research. The research about molecular mechanism of microorganism degradation was overviewed, various degrading path- ways including catechol meta-cleavage pathway and gentisate pathway were intro- duced, and the latest progress in regulating genes of salicylate degradation was summarized.

Effect of Nitrogen on the Degradation of Cypermethrin and Its Metabolite 3-Phenoxybenzoic Acid in Soil

Increasing use of pyrethroid insecticides has resulted in concerns regarding potential effects on human health and ecosystems. Cypermethrin and its metabolite 3-phenoxybenzoic acid(PBA) have exerted adverse biological impacts on the environment;therefore,it is critically important to develop different methods to enhance their degradation. In this study,incubation experiments were conducted using samples of an Aquic Inceptisol supplied with nitrogen(N) in the form of NH4NO3 at different levels to investigate the effect of nitrogen on the degradation of cypermethrin and PBA in soil. The results indicated that appropriate N application can promote the degradation of cypermethrin and PBA in soil. The maximum degradation rates were 80.0% for cypermethrin after 14 days of incubation in the treatment with N at a rate of 122.1 kg ha-1 and 41.0% for PBA after 60 days of incubation in the treatment with N at a rate of 182.7 kg ha-1. The corresponding rates in the treatments without nitrogen were 62.7% for cypermethrin and 27.8% for PBA. However,oversupplying N significantly reduced degradation of these compounds. Enhancement of degradation could be explained by the stimulation of microbial activity after the addition of N. In particular,dehydrogenase activities in the soil generally increased with the addition of N,except in the soil where N was applied at the highest level. The lower degradation rate measured in the treatment with an oversupply of N may be attributed to the microbial metabolism shifts induced by high N.

An enhanced influence of sea surface temperature in the tropical northern Atlantic on the following winter ENSO since the early 1980s

Previous studies have revealed a connection between springtime sea surface temperature （SST） in the tropical northern Atlantic （TNA） and the succeeding wintertime El Nino-Southern Oscillation （ENSO）. The present analysis demonstrates that the linkage between springtime TNA SST and the following ENSO experiences an obvious interdecadal change around the early 1980s, with the connection being weak before but significant after. After the early 1980s, springtime positive TNA SST anomalies induce an anomalous cyclone over the northeastern subtropical Pacific and an anomalous Walker circulation with a descending branch over the tropical central-eastern Pacific. This leads to anomalous cold SST in the northeastern Pacific and an anomalous anticyclone over the western-central tropical Pacific, with anomalous easterlies to the equatorward side. As such, springtime TNA SST anomalies are followed by wintertime ENSO after the early 1980s. In contrast, before the early 1980s, anomalous cold SST in the northeastern Pacific and related anomalous easterlies over the western-central tropical Pacific are weak, corresponding to springtime positive TNA SST anomalies and resulting in a weak linkage between springtimeTNA SST and the succeeding wintertime ENSO. Further investigation implies that the change in the TNA SST-ENSO relationship is probably due to a change in springtime mean precipitation over the tropical Atlantic and South America.

Dechlorination of Chlorinated Aliphatic Compounds by Micro-scale Al-Zn-Mg/Fe Powders as Advanced Zero-valent Iron

Micro-scale Al-Zn-Mg/Fe composite powders (MAF) with high reactivity and good storage properties were prepared by reducing iron onto the surface of Al-Zn-Mg alloy powders. Experimental results show that MAF as advanced zero-valent iron are highly effective for degradation of chlorinated organic compounds. The efficiency of degradation for carbon tetrachloride and perchloroethylene is higher than 99% within a period of 2 h. The efficiency of degradation for trichloroethylene by MAF after storing for one month is equivalent to that by freshly prepared nano-size zero-valent iron particles.

Decreasing Trend in Summer Precipitation over the Western Sichuan Basin since the 1950s

Changing precipitation in the densely populated Sichuan basin may have a great impact on human life. This study analyzes the change in summer precipitation since 1951 over the western Sichuan basin, one of the regions of the heaviest rainfall in China, by using two datasets provided by the Chinese Meteorological Data Center. The results indicate that summer (from June to September) precipitation over the western Sichuan basin shows a significantly decreasing trend. The summer precipitation over this region has decreased by about 20% since the 1950s, with a rate of decrease of about 40 mm per decade.

Shift of the principal mode of Pan-Asian monsoon summer precipitation in terms of spatial pattern

This paper documents that the principal mode of Pan-Asian monsoon summer precipitation experienced a prominent interdecadal shift around 1992/1993 in terms of spatial pattern and major driving factors. During 1979-1992 （Period 1, P1）, Pan-Asian monsoon summer precipitation anomalies mainly display a meridional dipole pattern from north to south, whereas in the period 1993-2016 （Period 2, P2）, it shows a meridional tripole pattern instead. The summer precipitation in P1 is primarily associated with a combination of the developing phase （central-eastern Pacific type） and decaying phase （eastern Pacific type） of El Nino-Southem Oscillation （ENSO）; while in P2, it is mainly associated with the decaying phase of central-eastern-Pacific-type ENSO.

Advances in Biodegradation of Aflatoxins

Aflatoxins are secondary metabolites of fungi such as Aspergillus flavus and Aspergillus parasiticus. They are one of the contaminants most common in food and feed, with high toxicity and carcinogenicity. Aflatoxins usually enter animal body together with feed and then enter human body by food chain, thereby seriously threatening human health. In recent years, the degradation of aflatoxins has become a hot research topic. This study overviewed the characteristics and detoxification ways of aflatoxins, specifically for the advances in biodegradation and degradation products of aflatoxins.

Weaker connection between the Atlantic Multidecadal Oscillation and Indian summer rainfall since the mid-1990s

Previous studies have shown that the Atlantic Multidecadal Oscillation （AMO） can play an important role in modulating the variabilityoflndian summer monsoon rainfall （ISMR） over a 50-60-yr timescale. A significant positive correlation between the AMO and ISMR is found both in observations and models. However, instrumental records show that the relationship becomes non-significant or even of opposite sign after the mid-1990s, suggesting a weakening of the AMO-ISMR connection. The mechanism for the breakdown of the AMO-ISMR connection is investigated in the present work, and the results suggest that a substantial warming in the Indian-tropical western Pacific Ocean plays a role. The warming weakens the meridional gradient of tropospheric temperature between Eurasia and the indian Ocean, and reduces the meridional sea level pressure gradient between the Indian Subcontinent and Indian Ocean, weakening the Indian summer monsoon. Thus, warming in the Indian-tropical western Pacific Ocean seems responsible for the weakened connection between the AMO and ISM.

Interdecadal Variability of Spring Precipitation over South China and Its Associated Atmospheric Water Vapor Transport

The characteristics of spring precipitation and water vapor transport in South China were analyzed by using observational data and the National Centers for Environmental Prediction (NCEP) reanalysis data. The results show that, during the spring, each component of the water cycle (precipitation, wind field, specific humidity, water vapor transport, etc.) in South China exhibits a notable interdecadal variability. An abrupt increase in spring precipitation occurred in the early 1970s. During the dry period from 1958 to 1971, a water vapor flux divergence (positive divQ) existed in South China, which may have led to the deficiency in rainfall. However, during the wet period from 1973 to 1989, there was a remarkable water vapor flux convergence (negative divQ) in South China, which may have resulted in the higher rainfall. The interdecadal variability of water vapor transport is closely related to the interdecadal variability of wind fields, although the interdecadal variability of specific humidity also plays a role to some extent, and the interdecadal variability of the zonal water vapor transport contributes much more to the interdecadal variability of spring precipitation than the meridional water vapor transport.

The Relationship between the Interdecadal Variation of Summer Precipitation and Its Interannual Variability over the Middle and Lower Reaches of the Yangtze River Valley

The intensity of summer precipitation interannual variability is strongest over the middle and lower reaches of the Yangtze River Valley(MLYRV). The variability is larger than 1.5 mm d–1 and up to 35%–40% of the climatological mean summer precipitation. The relationship between the interdecadal change in the intensity of summer precipitation and its interannual variability over this area is investigated, by analyzing five gauged and re-constructed precipitation datasets. The relationship is found to be very weak over the MLYRV, with a correlation coefficient of only approximately 0.10. The Pacific Decadal Oscillation influences the western North Pacific subtropical high, which is responsible for the interdecadal change in summer precipitation over the MLYRV. However, the precipitation interannual variability is closely related to the ENSO events in the preceding winter due to its impact on the meridional displacement of the East Asian westerly jet. Different physical mechanisms cause different interdecadal variation in the intensity of summer precipitation and its interannual variability, and thus result in a poor relationship.

A tripole winter precipitation change pattern around the Tibetan Plateau in the late 1990s

Classical monsoon dynamics considers the winter/spring snow amount on the Tibetan Plateau(TP)as a major factor driving the East Asian summer monsoon(EASM)for its direct influence on the land-sea thermal contrast.Actually,the TP snow increased and decreased after the late 1970s and 1990s,respectively,accompanying the two major interdecadal changes in the EASM.Although studies have explored the possible mechanisms of the EASM interdecadal variations,and change in TP snow is considered as one of the major drivers,few studies have illustrated the underlying mechanisms of the interdecadal changes in the winter TP snow.This study reveals a tripole pattern of change,with decreased winter precipitation over the TP and an increase to its north and south after the late 1990s.Further analyses through numerical experiments demonstrate that the tropical Pacific SST changes in the late 1990s can robustly affect the winter TP precipitation through regulating the Walker and regional Hadley circulation.The cooling over the tropical central-eastern Pacific can enhance the Walker circulation cell over the Pacific and induce ascending motion anomalies over the Indo-Pacific region.These anomalies further drive descending motion anomalies over the TP and ascending motion anomalies to the north through regulating the regional Hadley circulation.Therefore,the positive-negative-positive winter precipitation anomalies around the TP are formed.This study improves the previously poor understanding of TP climate variation at interdecadal timescales.

Variability of Summer Monsoon Rainfall in India on Inter-Annual and Decadal Time Scales

Indian Summer Monsoon Rainfall （ISMR） exhibits a prominent inter-annual variability known as troposphere biennial oscillation.A season of deficient June to September monsoon rainfall in India is followed by warm sea surface temperature （SST） anomalies over the tropical Indian Ocean and cold SST anomalies over the westem Pacific Ocean.These anomalies persist until the following monsoon,which yields normal or excessive rainfall.Monsoon rainfall in India has shown decadal variability in the form of 30 year epochs of alternately occurring frequent and infrequent drought monsoons since 1841,when rainfall measurements began in India.Decadal oscillations of monsoon rainfall and the well known decadal oscillations in SSTs of the Atlantic and Pacific oceans have the same period of approximately 60 years and nearly the same temporal phase.In both of these variabilities,anomalies in monsoon heat source,such as deep convection,and middle latitude westerlies of the upper troposphere over south Asia have prominent roles.