Probabilities of marriage in two outer Hebridean islands, 1861-1990.

A study has been made of the probabilities of marriage of females and males aged 15-49 (either as a whole or in 5-year age groups) in two Outer Hebridean islands, Harris and Barra. The results were compared with ages of marriage and with the frequencies of permanent celibacy. The marriages took place between 1861 and 1990. Median ages of marriage rose to maxima in the 1930s and 1940s, then fell steeply, levelling out latterly. Permanent celibacy was consistently high among females, but rose from much lower levels in males to maxima in the 1970s and 1980s. It is concluded that in these populations age at marriage and the extent of permanent celibacy are largely independent of one another. In both islands the overall probabilities of females marrying fell until the 1920s, and then rose. The last decades showed stability (Barra) and a fall (Harris). Males showed only slight falls to about 1910; data were absent for between 1911 and 1960, but subsequently there was little rise in probability. These overall changes seemed to be associated with reciprocal variations in probabilities in the younger and older age groups. Declining overall probabilities were associated with declines in younger and increases in older age-group probabilities, and vice versa. Non-parametric correlations between median ages of marriage and probability of marriage were negative and generally significant for the 15-19 age group. Among the older age groups coefficients were generally positive. There was some evidence of an association between probability of marriage and sex ratio in any group of potential mates. The effect appeared more marked among 15- to 19-year-old females. Local factors which might explain at least part of the decline in nuptiality for the greater part of the period under study include the decline in the fishing industry and the 'land hunger' which existed until the late 1920s. This decline is interpreted as a 'Malthusian' response to economic and social conditions, but it coexisted with a 'neo-Malthusian' strategy, in the shape of declining marital fertility. The 'Malthusian' strategy seems to have been largely abandoned around the 1950s, but it may have reappeared during the 1980s.     

KEY WORD INDEX TO VOLUME 1-10, 1990-2000

31P NMR fnuclear magenetic resonancel………. ......……................….…1992;2:129.137‘~Ca2 accumulation.….……....…..1998;8:41.5097 KDa residual protein…….....…....1992;2:1-13 Agrobacterium tumefaciens.…….….…1990;1:1—10Acanthopanax brachypus...............1997;7:99.106AIlium sativt//D.…….....…….....1995;5:155.164A111tim cepa...............……...…1992:2:153,163Arabidopsis thallana...……....…..1996;6:125.136Arabidopsis……….……….…....1998;8:119.134aberrant di＆ren…     

Author index, vol. 190, 1990

Author index, vol. 190, 1990     

1990—2010年淮河流域人类活动净氮输入

1990—2010年,淮河流域粮食产量由6414×10⁴ t增长到10121×10⁴ t(增幅为58%),城市化率由13%增长到35%(涨幅为22%),流域社会经济发生了显著变化.从流域整体定量评估人类活动所带来的生态环境影响将为区域生态环境管理提供科学依据.本文估算淮河流域1990—2010年人类活动净氮输入(NANI)的空间分布及变化趋势.结果表明: 研究期间,淮河流域氮输入量呈现出增加趋势;1990—2001年流域内氮输入量快速增加,2001年后氮输入增加趋势减缓.1990年氮输入量为17232 kg N·km^-2·a^-1,2003年氮输入量最高,为28771 kg N·km^-2·a^-1,2010年回落为26415 kg N·km^-2·a^-1.从氮输入的组成上来看,化肥和大气氮沉降仍然是最主要的输入来源,其次为食品/饲料和生物固氮的输入.化肥和大气沉降输入占总氮输入的比例持续增加,由1990年的64%和16%分别增长至2010年的77%和19%.单纯以增施化肥来实现粮食增产、化石燃料大量燃烧来推动经济发展的观念,应切实转变到改善农业耕种技术、实现新能源的发展轨道上来,进而推动社会经济的可持续发展.