“绿色革命之父”诺曼·布劳格

布劳格是国际著名的小麦育种学家、诺贝尔和平奖得主,其培育的20多个小麦矮杆高产品种对世界粮食生产产生了积极影响。因其终生致力于以农业技术创新消除发展中国家的饥饿和贫困问题,他被国际社会誉为最杰出的反饥饿斗士、绿色革命之父。本文对布劳格的生平、育种科研和推广活动以及社会贡献进行系统介绍。     

An Empirical Analysis on the Relationship betweenExports and Economic Growth in China

1IntroductionThedebateontheroleofexportsintheeconomicgrowthofdevelopingcountrieshasshiftedaremarkablewayfromimportsubstitutiontowardsexport-ledgrowth(ELG)andincreasedopenness.Therehasbeenanumberofempiricalstudiesthathavedocumentedastrongandpositiverelationshipbetweenexportsandeconomicgrowth(see,forexample,Michaely,1977,Balassa,1985;Krueger,1990;Tyler,1981,ffem,1985;Chow,1987;Fosu,1990;KhanandSqib,1983;SinguptaandEspana,1994).Chinahasbeenpursuingeconoicreformandoper-doorpoliciessince1978,a…     

Breeding behaviour and mating success of Phyllomedusa rohdei (Anura,Hylidae) in south‐eastern Brazil

Observations on the courtship behaviour, mating behaviour and mating success of a leaf‐frog, Phyllomedusa rohdei, population were conducted in a temporary flooded site of the Atlantic Forest, south‐eastern Brazil. We did not find any influence of size and body weight on male mating success across three scales: seasonal, nightly chorus and local groups (males found within 1?m of a mated pair). In addition, no evidence was found that female Phyllomedusa rohdei exhibit overt mate choice. The formation of mated pairs in P. rohdei occurred because males moved toward the females, rather than reverse. The only variable that was significantly related to male mating success was the number of nights of participation in chorus activity. Besides calling tactics, males showed active searching behaviour. There was no evidence of size‐ and mass‐assortative mating, and a high percentage of fertilization at all size and mass ratios of males and females was observed. Clutches in this species are produced in the same manner found in others members of Phyllomedusa; a purse‐like nest is made over water by folding a leaf around the egg mass (embryos and fluid‐filled capsules). Finally, we supply a list of several studies that examined the relationship between size or mass ratios of males and females in amplexus and its influence on fertilization rate, and show that size‐assortative mating in anurans is inconsistent (present in some species but not in other).     

Microhabitat choice and differential use by anurans in forest streams in southeastern Brazil

The use of space by anuran amphibians during reproductive activities was studied at eight forest streams in the Reserva Particular do Patrimônio Natural Santuário do Caraça, southeastern Brazil. Identified microhabitats were classified into 18 types based on substrate and height above ground/water. A total of 440 individual anurans of 19 species was recorded in these microhabitat types. Electivity indices were calculated for the three most abundant species and indicated that specimens actively selected microhabitats. Species with broad niches (generalists) did not occur in more streams than species with narrow niches (specialists), and streams with higher species richness did not contain more specialists. Species showed high levels of overlap in microhabitat use, which were not related to the number of co‐occurring species. The distribution patterns observed in the studied anuran assemblages likely reflect specific reproductive preferences and colonization abilities rather than the result of competitive pressures.     

Breeding behaviour of the Omei tree frog Rhacophorus omeimontis (Anura: Rachophoridae) in a subtropical montane region

Breeding behaviour of the Omei tree frog, Rhacophorus omeimontis, was studied during the egg-laying period (mid-April to late June) in south-west China. The operational sex ratio of the breeding population was male-biased at 3.0?±?0.8 (mean?±?SD) on a nightly basis in Pond A and 4.3?±?1.1 in Pond B. Pairs with a male clasping a female occurred in ponds first; the amplectant pairs moved to a neighbouring plant and then released foam in leaves 14–370 cm above the pond's water surface. Immediately, other males came to join the pair, forming an amplexing group of 2 to 7 males (for all 45 breeding units observed). Among the males no direct physical competition for possession of the females was observed. Females produced foam which surrounded the subsequently-laid eggs. The whole process of oviposition lasted 45–65 minutes. After ovipositing, males left the female, the female folded and lined neighbouring leaves with more foam produced to surround the eggs further. This process took 15–45 minutes. The numbers of eggs in a clutch ranged from 457 to 837 and eggs were between 2.9 and 3.4 mm in diameter; those two measures were negatively correlated with each other. Eggs hatched after 12–17 days; the larval period lasted 63–78 days. Fertilization success was positively related to the number of males participating in matings.     

Habitat characterization and potential distribution of Tylototriton vietnamensis in northern Vietnam

The habitat preferences of the endemic Vietnam Crocodile Newt, Tylototriton vietnamensis were investigated on two scales: (1) at Yen Tu Nature Reserve, Bac Giang Province, Vietnam, while compiling information about pond occupancy and developing a qualitative comparison among breeding sites and (2) by developing a Species Distribution Model based on climate and land cover data identifying further suitable habitats in northern Vietnam. A factor analysis followed by a multiple linear regression showed 94% support for our occupancy ranking model. Our results suggest that T. vietnamensis preferentially inhabits small pools with long hydroperiod and pH above 4.3. Suitable areas for the species have higher incidence in northern regions, where undisturbed vegetation and temperature-related variables seem to make greater contributions. Additionally, these potentially suitable areas are strongly fragmented and only a few are under IUCN protection, increasing their vulnerability towards further degradation.     

Validating Policy‐Induced Economic Change Using Sequential General Equilibrium SAMs

We present a novel sequential approach that explores the capacity of Computable general equilibrium (CGE) models to track down policy‐induced economic changes and their ability to generate contrastable data. We use an empirical Social accounting matrix (SAM) of the region of Andalusia, in the south of Spain, to construct an initial CGE model. This model is then perturbed with a set of policy shocks related to EU Structural Funds invested into Andalusia. These shocks are accompanied by some parameter adjustments that pick up the main external changes not explained by the model. We generate a sequence of model‐produced virtual SAMs. We then compare the last virtual SAM in the sequence with a new available empirical SAM. This allows us to check relatedness, for the same year, between the model produced and the empirical SAMs. The results show a good fit to the empirical data, providing further support to the CGE modelling tool. Copyright © 2016 John Wiley & Sons, Ltd.     

关于Dirichlet L-函数的二次均值

利用经典的Kloostermann和估计与解析方法讨论了Dirichlet L-函数的一个二次加权均值,得出了一个有趣的均值分布定理.     

Characteristics of dry friction backward whirl-A self-excited oscillation in rotor-to-stator contact systems

In this paper, the response characteristics of dry friction backward whirl of a general rotor/stator model, which accounts for both the dynamics of the rotor and the stator as well as the friction and the deformation at the contact surfaces, are investigated. The existence boundaries and the whirl frequencies of the dry friction backward whirl are determined analytically. It is found that there are two or three existence boundaries of the dry friction backward whirl that usually form two existence regions, ...     

Larval development of the coronuloid barnacles Austrobalanus imperator (Darwin), Tetraclitella purpurascens (Wood) and Tesseropora rosea (Krauss) (Cirripedia,Tetraclitidae)

The presence of embryos in the mantle cavity of A. imperator, T. purpurascens and T. rosea was monitored over two years. Tesseropora rosea showed a clearly defined breeding season in summer and early autumn. Seasonal breeding in A. imperator and T. purpurascens was less well defined, a small number of gravid individuals being present during most of the year. Breeding increased during the late autumn and early winter in A. imperator and during winter, spring and early summer in T. purpurascens. The larval stages of A. imperator, T. purpurascens and T. rosea are described from larvae reared in the laboratory. Separation of the larval stages between these species depends on fine morphological detail. Distinctive larval features permit the separation of coronuloid larvae from those of the other balanomorph superfamilies, but coronuloid nauplii resemble balanoid nauplii more than chthamaloid nauplii.