This paper investigates changes over time in the proportion of the male and female population aged 15 and over who are employed. It is especially aimed at studying the influence of changes in the age composition of the population on this indicator. The main findings are: (a) while the underlying trends for males and females are in the opposite direction, both male and female employment ratios fall in recession and rise in recoveries; (b) changes in the age composition of the population (ageing, per se) can explain only a very small amount of the changes in the aggregate employment ratio for both males and females over the period 1978–2001; (c) the falling aggregate male employment ratio is not primarily or even largely a result of movements out of employment by older workers, indeed, over half of the reduction in the aggregate employment ratio for males is due to falling employment ratios for prime working-age males. Policy implications are discussed in the concluding section.

This paper looks at the effects of changes in the age composition of the labour force on aggregate male and female unemployment rates. While it has been common to look at aggregate participation rate changes in terms of a weighted average over age groups this seems not to be the case for unemployment. We show in this paper that changes in the age composition of the labour force (driven mainly by changes in the age distribution of the population) has affected the aggregate unemployment rates in a systematic and, with hindsight, predictable manner. Amongst other things, we show that in the past decade or so, policy makers have benefited from a not inconsequential “free lunch” in that changes in the age composition of the labour force have been pulling the aggregate unemployment rates down below what it would otherwise be by around one percent of the labour force. We also show that this free lunch is now coming to an end.

This paper investigates two related matters. First, what proportion of the population is represented by the matched sample (i.e. by the gross flows data) in the Labour Force Survey, why is this proportion what it is and why does it vary over time? Second, given that around 20% of the population are not represented in the matched sample, how representative are labour market indices derived from the matched sample data and, if biases are present, what is the source and what are the implications of the bias?

This year marks the 200th anniversary of the birth of Karl Marx, the last of the classical political economists. This article aims to mark the occasion by drawing attention to some of his key works in economics and to present some of his ideas in a way that will make sense to readers not familiar with or very much interested in the complexities of the labour theory of value. I begin with a brief biography and a summary of his main works in economics. I then explore in some detail ideas related to the economic surplus, unpaid labour and exploitation, and attempt to tease out the implications of his analysis for the determination of the wage share. While I argue that Marx has not succeeded in providing adequate theoretical support for his prediction that the wage share will fall as capital accumulates, he has nonetheless provided a very interesting and insightful collection of ideas by which we may, even today, approach a wide range of issues relating to production and distribution.

Barrett’s oesophagus (BE) is the precursor of oesophageal adenocarcinoma, which has become the most common type of oesophageal cancer in many Western populations. Existing evidence on diet and risk of BE predominantly comes from case–control studies, which are subject to recall bias in measurement of diet. We aimed to investigate the potential effect of diet, including macronutrients, carotenoids, food groups, specific food items, beverages and dietary scores, on risk of BE in over 20 000 participants of the Melbourne Collaborative Cohort Study. Diet at baseline (1990–1994) was measured using a food frequency questionnaire. The outcome was BE diagnosed between baseline and follow-up (2007–2010). Logistic regression models were used to estimate OR and 95 % CI for diet in relation to risk of BE. Intakes of leafy vegetables and fruit were inversely associated with risk of BE (highest v. lowest quartile: OR = 0·59; CI: 0·38, 0·94; P-trend = 0·02 and OR = 0·58; CI: 0·37, 0·93; P-trend = 0·02 respectively), as were dietary fibre and carotenoids. Stronger associations were observed for food than the nutrients found in them. Positive associations were observed for discretionary food (OR = 1·54; CI: 0·97, 2·44; P-trend = 0·04) and total fat intake (OR per 10 g/d = 1·11; CI: 1·00, 1·23), the association for fat was less robust in sensitivity analyses. No association was observed for meat, protein, dairy products or diet scores. Diet is a potential modifiable risk factor for BE. Public health and clinical guidelines that incorporate dietary recommendations could contribute to reduction in risk of BE and, thereby, oesophageal adenocarcinoma.

Two vanadates, tangeïte and volborthite, new to Britain, their association with vanadiferous nodules, and their geological environment are described. A percentage composition graph for vanadium taken across a vanadiferous nodule, by scanning electron probe, is given.

To improve understanding of relationships between crop diversity, weed management practices, and weed population dynamics, we used data from a field experiment and matrix models to examine how contrasting crop rotations affect velvetleaf. We compared a 2-yr rotation system (corn–soybean) managed with conventional rates of herbicides with a 4-yr rotation (corn–soybean–triticale + alfalfa–alfalfa) that received 82% less herbicide. In November 2002, a pulse of velvetleaf seeds (500 seeds m−2) was added to 7- by 7-m areas within replicate plots of each crop phase–rotation system combination. Velvetleaf seed, seedling, and reproductive adult population densities, seed production, and seed losses to predators were measured during the next year. Velvetleaf seed production was greater in the 4-yr rotation than in the 2-yr rotation (460 vs. 16 seeds m−2). Averaged over 12 sampling periods from late May to mid-November 2003, loss of velvetleaf seeds to predators also was greater in the 4-yr rotation than in the 2-yr rotation (32 vs. 17% per 2 d). Modeling analyses indicated that velvetleaf density in the 4-yr rotation should decline if cumulative losses of seeds produced in the soybean phase exceeded 40%. Achieving such a level of predation appears possible, given the observed rates of velvetleaf seed predation. In addition, no tillage occurs in the 4-yr rotation for 26 mo after soybean harvest, thus favoring seed exposure on the soil surface to predators. Models that included estimates of seed predation indicated that to prevent increases in velvetleaf density, weed control efficacy in soybean must be ≥ 93% in the 2-yr rotation, but could drop to 86% in the 4-yr rotation. These results support the hypothesis that diverse rotations that exploit multiple stress and mortality factors, including weed seed predation, can contribute to effective weed suppression with less reliance on herbicides.

An extensive ancient archeologic site containing lithic artifacts and associated with mammoth remains was reported at Chinitna Bay, southern Alaska in 1943. The presence of such a site adjacent to the continental shelf at the base of the rugged Aleutian Range suggested that humans may have inhabited the inner shelf environment during the late Pleistocene at times of lowered sea level. Because of the site's potential significance, an interdisciplinary research team relocated and reinvestigated the area in 1978, but failed to find evidence of prehistoric human habitation. Geologic studies and radiocarbon dating indicate that the strata reported at the site are intertidal in origin, very late Holocene in age, and have undergone significant tectonic movement in the recent past. These observations indicate that the previously published observations of the Chinitna Bay site are probably invalid.

In 1980 a large proboscidean femur, probably Mammuthus sp., was found in situ in a bluff exposure at the mouth of the Tyone River in the northwestern part of the Copper River Basin, Alaska. The regional setting, stratigraphy, radiocarbon chronology, flora, and implications of the fossil locality, which represents the first documented occurrence of Pleistocene terrestrial mammalian fauna in southern Alaska, are described. Radiocarbon dates and stratigraphic relations at the site indicate that the sediments containing the fossil accumulated during the transition from interstadial to glacial conditions during terminal middle Wisconsin time. During this interval the immediate vicinity was unforested and large areas of south-central Alaska may have been available for faunal and possibly human habitation. This documented find, dated at 29,450 ± 610 14C yr B.P., extends the known range for Pleistocene mammals and possibly steppe-tundra conditions south-ward at least 150 km, and suggests that mountain passes through the Alaska Range to the north were ice free during the last part of the middle Wisconsin interstadial.